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REAL LIFE SAFETY ONE STAR IS ALL YOU NEED 2/2014

REAL LIFE SAFETY

One Star Is All You Need

ALL-ENCOMPASSING SAFETY CONCEPT INTELLIGENT DRIVE AND AUTONOMOUS DRIVING THE ROAD TO ACCIDENT FREE TRAFFIC Daimler Communications 70546 Stuttgart, Germany www.daimler.com – www.daimler.mobi Mercedes-Benz – A Daimler Brand

REAL LIFE SAFETY BASICS

CONTENTS PRE-SAFE®

42 RESTRAINT SYSTEMS 60

The integral concept of Mercedes-Benz safety development is to avoid accidents and to mitigate consequences. The company calls this Real Life Safety. This book gives insight into the broad range of safety innovations, test procedures and development tools of Mercedes-Benz – yesterday, today and tomorrow.

10 NETWORKED SENSOR SYSTEM 360° all-round vision

16 INTERVIEW Dr Michael Hafner, Head of driver assistance systems

18 DEVELOPMENT TOOLS State-of-the-art methodology

28 ACCIDENT RESEARCH Reality is the yardstick

34 BÉLA BARÉNYI The father of safety

36 EXPERIMENTAL SAFETY VEHICLES

44 BASIC FUNCTIONS Precautionary safety measures

48 NEW FUNCTIONS Focus on following traffic

50 INTERVIEW Prof Rodolfo Schöneburg, Michael Fehring, Karl-Heinz Baumann, the original brains behind PRE-SAFE®

56 DEMONSTRATOR

62 CHILD SEATS Small passengers, great need for protection

66 AIRBAGS Blow up

76 SEAT BELT Number one lifesaver

82 DID YOU KNOW Facts, figures and curiosities

Realistic impression

58 DID YOU KNOW Facts, figures and curiosities

Experience the future

40 DID YOU KNOW Facts, figures and curiosities

REAL LIFE SAFETY ASSISTANTS

86 ABS/ESP® Controlled vehicle dynamics

96 BAS PLUS Recognising danger, supporting the driver

100 LANE KEEPING AND BLIND SPOT On the right track

104 COLLISION PREVENTION ASSIST Prevention of rear-end collisions

106 TRAFFIC SIGN RECOGNITION Orientation in the traffic sign jungle

108 PARKING Automatic entry into parking spaces

110 DRIVING ACADEMY Driver training for every level

114 DID YOU KNOW Facts, figures and curiosities

84 DRIVER FITNESS

118 NIGHT VIEW ASSIST Better vision when driving at night

122 HEAD-UP DISPLAY Information in the driver’s field of vision

124 HEADLAMPS Intelligent Light Systems and lighting history

132 RESEARCH Customer Research Center

116

CONTENTS CRASH TESTING

150 TEST PROCEDURES Organised destruction

164 DUMMIES They suffer for us

170 POST-SAFE Rapid rescue

174 DID YOU KNOW Facts, figures and curiosities

148 OUTLOOK

176

178 CAR-TO-X COMMUNICATION Vehicles in a dialogue

182 AUTONOMOUS DRIVING The self-driving car

186 INTERVIEW Prof Ralf G. Herrtwich, Daimler advance development

188 DID YOU KNOW Facts, figures and curiosities

136 ATTENTION ASSIST Preventing fatigue

138 STOP&GO PILOT More comfort in tailbacks

142 MAGIC BODY CONTROL The world’s first suspension system with “eyes”

146 DID YOU KNOW Facts, figures and curiosities

6 EDITORIAL 190 KEY MILESTONES 195 IMPRINT

MERCEDES-BENZ INTELLIGENT DRIVE ONE STAR IS ALL YOU NEED

DEAR READERS,

afety has always been a core competence of Mercedes-Benz. This is witnessed by the numerous technical innovations with which we have continued to set standards in both Active and Passive Safety since the invention of the automobile in 1886. At the same time Daimler AG is meeting a higher responsibility. We see safety as a comprehensive system that serves all. Every car driver knows and uses the milestones achieved by this ongoing effort: from the rigid passenger cell (patented in 1951 and first introduced into series production in the Mercedes-Benz W 111 series in 1959) to ABS (introduced in the

Every drive in a Mercedes-Benz is “Intelligent Drive” in numerous situations on the road. An overview of the different systems: 1 COLLISION PREVENTION ASSIST (PLUS) 2 DISTRONIC PLUS with Steering Assist and Stop&Go Pilot 3 BAS PLUS with Cross-Traffic Assist 4 PRE-SAFE® Brake with Pedestrian Detection

W 116-series S-Class in 1978), the airbag (introduced in the W 126-series S-Class in 1981, initially for the driver) and the Electronic Stability Programme ESP® (presented in a C 140-series S-Class Coupé in 1995). ABS and ESP® today are the standard for all passenger cars registered in Europe. The innovative solutions in each of the brand’s new models show that for the future too, vehicle safety is one of the most important concerns for Mercedes-Benz engineers. And this applies right across all vehicle classes: examples include COLLISION PREVENTION ASSIST, which was introduced as standard with the new compact-class

generation in 2011, or the Stop&Go Pilot first offered in the S- and E-Class and now also available for the new C-Class. In 1966 our safety experts Béla Barényi and Hans Scherenberg formulated the distinction between Active and Passive Safety. Thanks to the integral safety concept of Mercedes-Benz, both areas now interlock seamlessly. Because in 2002 a new era in vehicle safety dawned in the MercedesBenz S-Class with PRE-SAFE® : for the first time technology was able to recognise an impending collision in advance, and prepare both vehicle and occupants for a possible impact. Since then,

active and passive safety technology has worked together in synergy. And more than ten years after the introduction of PRE-SAFE®, we are now going a step further: intelligent assistance systems analyse complex situations and use improved environmental sensor systems to recognise potentially dangerous traffic situations even more efficiently. This can prevent accidents, or considerably mitigate their possible consequences. We call the intelligent networking of sensors and systems for a new dimension in motoring “Mercedes-Benz Intelligent Drive”. With Intelligent Drive we are systematically following our path towards accident-free driving. Because for us at Mercedes-Benz, Intelligent Drive is also the entry-point into the era of autonomous driving. In addition, the intelligent networking of vehicles with each other, and with the infrastructure, has the potential to improve general traffic safety even further. Our intention with this magazine is to give you an overview of the safety philosophy at Mercedes-Benz – from the early basics to constantly improved development tools, and right up to trailblazing innovations in all safety-related areas. I wish you an enjoyable read.

5 PRE-SAFE® PLUS 6 PRE-SAFE®

Thomas Weber

7 Active Lane Keeping Assist 8 Active Blind Spot Assist 9 Adaptive Highbeam Assist Plus 10 Night View Assist Plus 11 Active Parking Assist with PARKTRONIC 12 360° Camera 13 Traffic Sign Assist 14 ATTENTION ASSIST 15 Intelligent Light System 16 LED Headlamps 17 Crosswind Assist 18 ESP®/ABS/BAS 19 4MATIC

Prof Dr Thomas Weber is a Member of the Board of Management of Daimler AG and responsible for Group Research and Mercedes-Benz Cars Development

Photo: Per-Gunnar Ostby/Getty Images

BASICS

INTELLIGENT DRIVE IS BASED ON SENSORS THAT MONITOR THE SURROUNDINGS, ADVANCED TOOLS TO SUPPORT DEVELOPMENT AND

ACCIDENT RESEARCH FOR ANALYSING ACTUAL EVENTS. MEANALL-ROUND VIEW The eyes of a CHAMELEON move independently of each other. This gives a field of vision of 342 degrees and a blind spot of just 18 degrees. These creatures can see sharply – and in colour – up to one kilometre away.

RESEARCH VEHICLES PROVIDE A GLIMPSE INTO THE

WHILE,

FUTURE. 9

BASICS SENSOR FUSION

THANKS TO TWO “CAMERA EYES”, THE NEW STEREO CAMERA HAS A THREE-DIMENSIONAL

NETWORKED SENSOR SYSTEM NETWOR

360° ALL-ROUN ALL-ROUND VISION RADAR, STEREO CAMERA AND ULTRASONIC SYSTEMS More sensors – more protection Multi Mode Radar 80 m range / opening angle 16° and 30 m range / opening angle 80°

VIEW OF THE AREA UP TO ABOUT 50 METRES IN FRONT OF THE VEHICLE AND, IN THE FORM OF “6D VISION”, CAN DETECT THE POSITION AND MOVEMENT OF OBJECTS. THE SYSTEM MONITORS THE SURROUNDINGS AHEAD OF THE VEHICLE OVER A RANGE OF UP TO 500 METRES. THIS DATA IS COMBINED WITH DATA FROM RADAR AND ULTRASONIC SENSORS.

Stereo Multi-Purpose Camera 500 m range, with 3D capability over a range of 50 m / opening angle 45°

Long Range Radar With Mid-Range Scan 200 m range / opening angle 18° 60 m range / opening angle 60°

Ultrasonic Sensors 1.2 m / 4.5 m range

Short Range Radar 0.2 m - 30 m range / opening angle 80°

Near / Far Infrared Camera 160 m range / opening angle 20°

BASICS SENSOR FUSION

Stereo camera: the car’s eyes are fitted as high as possible in the vicinity of the rear-view mirror

ighly sophisticated sensors and accordingly networked algorithms provide the foundation for innovative new

functions. As part of “sensor fusion”, DISTRONIC PLUS with Steering Assist, BAS PLUS and PRE-SAFE ® Brake all employ the same stereo camera and multi-stage radar sensors.

Mercedes-Benz is making a major leap forward with the introduction of the Stereo Multi-Purpose Camera (SMPC), or stereo camera for short. Just like the Multi-Purpose Camera

(MPC) fitted previously, it is positioned behind the windscreen in the vicinity of the rear-view mirror. It has an aperture angle of 45° and is capable of spatially detecting objects moving

crossways ahead and also pedestrians, and calculating their path. The camera’s two “eyes” provide it with a three-dimensional view of the area up to approx. 50 metres in front of the

EYES AND EARS Sensor system in detail

INTELLIGENT DRIVE Sensors enhance capabilities of assist systems US Ultrasonic Sensors

SR Short Range Radar

SS Steering Angle Sensor

LR Long Range Radar

RS Rain Sensor

MR Multi Mode Radar

US US

US MR

SC Stereo Multi-Purpose Camera C Camera

C C

SC US

US SR US

A wide range of sensors give the latest vehicles from Mercedes-Benz eyes and ears. In the S-Class, examples include: RADAR 2 x short-range radars at the front (30 m, 80°) 1 x long-range radar at the front (200 m, 18°) with medium-range detection (60 m, 60°) 2 x short-range radars on the sides at the rear (30 m, 80°) 1 x multi-mode radar at the rear (30 m, 80° and 80 m, 16°) STEREOCAMERA Stereo Multi-Purpose Camera (SMPC) located behind the windscreen in the vicinity of the rear-view mirror (range 500 m, incl. 3D capability for approx. 50 m, 45°) 12 ULTRASONIC SENSORS 4 each at the front/rear + 2 each on the left/right in the front and rear bumpers) 4 CAMERAS AS PART OF A 360° CAMERA SYSTEM 1 each at the front in the radiator grille/behind in the handle recess/bottom of the exterior mirror housings, vertical angle of approx. 130°, horizontal > 180°, resolution 1 MP (1280-800 pixels)

US US SR US LR US C US SR US US

“Mercedes-Benz Intelligent Drive”: the helpers in the background make common use of the sensors. Vehicles equipped with Night View Assist Plus additionally have a Short Range Infrared Camera in the windshield and a Long Range Infrared Camera in the front grille

Radar sensors: the transmitting and receiving modules for the various radar sensors are concealed in the bumpers and radiator grille

BASICS SENSOR FUSION

vehicle. This system is able to monitor the overall situation ahead over a range of up to 500 metres. In this way, the new camera supplies data that is processed further by various systems. Based on the location (3D) of a detected object, the stereo camera also provides additional information for active safety systems: it is possible to determine a direction of movement for

every single pixel on the horizontal, vertical and longitudinal axis. It is clear from this six-dimensional

CAMERA CAPTURES MOVEMENT OF OBJECTS IN SPACE (6D) recognition whether the object is moving and where to. When combined with object classification based on

common features, this stereo camera technique enhances confidence that full brake application by the vehicle is possible in the event that the driver fails to respond to an object’s presence. Thanks to such system accuracy, the stereo camera is able to calculate the location of impact for a potential collision and use the remaining time available as effectively as possible, in order to take

cial. Gaining a few hundred milliseconds for full brake application might make the difference between light and much more serious injuries. Intelligent algorithms evaluate this information in order to detect and carry out spatial classification of vehicles that are driving ahead, oncoming or crossing, as well as pedestrians and a variety of traffic signs and road markings within a large field of vision. Whereas the stereo camera’s lenses act as the car’s eyes, the radar sensors are its ears, so to speak, and provide additional data. The

precautions. In the process, the stereo camera provides support across the entire speed range. Because the stereo camera system may also determine potential evasive manoeuvres for the vehicle within its field of vision, it is even possible for a collision warning or automatic braking to be initiated sooner if no means of evasion is available. This can be benefi-

RADAR SENSORS ACT AS THE CAR’S EARS

Lab testing: hardware-in-the-loop test station for component testing

MAKING THE “SEEING” CAR A REALITY Eight years of development The first prototypes featuring technology to detect crossing traffic emerged back in 2005. This was followed by eight years of intensive development activities in the lab, on test sites and on the road. Series production commenced with the launches of the E-Class and S-Class in 2013. From March, the new assistance systems will become available in the executive segment for the first time, with the new C-Class. Michael Schumacher himself shared his wealth of experience by providing input on the final calibration drives.

system of radar sensors comprises two short-range radar sensors in the front bumper with a range of 30 m and a beam angle of 80°, which are complemented by a longrange radar (200 m, 18°) including medium-range detection (60 m, 60°). The data from the camera and radars is amalgamated in a control unit in order to provide the system-specific data for the various functions. An extensive system of additional sensors is able to keep an eye on the current driving state and the driver’s reactions. If the sensors detect a hazardous situation, they are able to feed the algorithms for all manner of assistance systems with data in order to provide just the right support for the specific situation. ■

2005 test drive: prototype for detecting crossing traffic in a Mercedes-Benz E-Class (model series 211) with stereo camera above the screen

BASICS INTERVIEW

ince the beginning of this year Dr Michael Hafner (43) heads the unit for the Development of Driver Assistance Systems and Active Safety. Holding a doctorate in engineering, his previous areas of activity included the associated field of brake control and suspension systems, control technology and neuronal networks.

The eyes of his cars: Dr Hafner and the stereoscopic camera, shown here for demonstration above the same item installed in the car

It was in 2013 that Mercedes-Benz achieved the last quantum leap in the field of assistance systems, thanks to improved sensors and sensor fusion. Only a few years ago, the idea that a car could have all-round vision would have been dismissed as utopian. Does this mean that assistance systems have reached their technical limits, or where do you still see potential for the future? Dr Hafner: It is quite right that the introduction of the stereo camera and fusion of the data from various sensors were decisive steps on which we spent a good eight years of development time – and which now give us a clear advantage over our competitors. Our task for the future is to refine the sensor signals and algorithms used by the assistance systems to support the driver. We also want to ensure that these systems are available on the broadest possible basis across all our model series.

DR MICHAEL HAFNER

“ONE STEP AHEAD” A CONVERSATION WITH THE HEAD OF DRIVER ASSISTANCE SYSTEMS

You have already done this successfully with the introduction of COLLISION PREVENTION ASSIST as standard in the B-Class three years ago. Dr Hafner: Yes, that was an important breakthrough. And with COLLISION

PREVENTION ASSIST PLUS we are taking another major step, as we can now initiate autonomous braking in certain situations if the driver fails to react to the warning when an accident threatens. We are also proud of the fact that it has been less than a year before the assistance systems from the S- and E-Class have also become available in the C-Class. Are there already accident statistics available that confirm the extra safety provided by the radar-based collision warning system COLLISION PREVENTION ASSIST in the A-, B- and CLA-Class? Dr Hafner: Since the introduction of autonomous emergency braking functions with DISTRONIC PLUS, we know that around one third fewer rear-end collisions have been recorded and that the impact severity was reduced in just under two thirds of cases. Incidentally, there are also fewer cases of vehicles equipped with this being impacted from the rear, as timely braking allows more reaction time for following traffic. The more numerous and complex assistance systems become, the less car drivers understand their functions and operating

principles in detail. Do we need more explanatory symbols, for example the coffee cup in the case of ATTENTION ASSIST? Dr Hafner: Not necessarily. Very good assistance systems normally work in the background, or support drivers unobtrusively without taking control. What is important is that the assistants provide support when they are needed. We show this with symbols or small graphics when they do, so that the driver is able to identify the assistance system that is intervening. Customers wishing to learn about their functions in more detail can do so by referring to the owner’s manual, which f.i. in the case of the S-Class is also available on-screen in digital form. And of course magazines such as this also help to explain the systems. With SIM-City, MercedesBenz has a dedicated test site for the testing of assistance systems. Does this sometimes lead to crashes, or are these completely prevented by tools such as the driving robot, the balloon car that simulates rear-end collisions or the radar-reflecting padding for lateral proximity? Dr Hafner: At MercedesBenz we not only attach the greatest importance to safety in our vehicles, but also

during their development. We really do use driving robots to perform dangerous manoeuvres, or we resort to our driving simulator, one of the most modern in the world. What part do suppliers play during the development of assistance systems? How can the advantage over competitors be sustained? Dr Hafner: Mercedes-Benz works together closely and confidentially with suppliers, especially where the hardware is concerned. However we keep the key knowhow with respect to data fusion, the functional aspects of our systems and their integration into the vehicle in-house. We are therefore confident that we can also remain at least one step ahead of our competitors in the future. Which assistance system do you appreciate and use most yourself? Dr Hafner: Personally I find the new DISTRONIC PLUS with Steering Assist to be a very convenient help, especially in tailbacks thanks to the Stop&Go Pilot. I also like the fact that the PRE-SAFE ® braking functions are always on standby in the background, although they will hopefully never be needed. ■

BASICS DEVELOPMENT TOOLS

STATE-OF-THE-ART METHODOLOGY

INNOVATIVE TOOLS AS CARL BENZ FORESAW IN 1925, “THE LOVE OF INVENTION NEVER CEASES”. THE COMPANY’S FOUNDER WOULD ALSO HAVE BEEN A FAN OF THE INNOVATIVE METHODS THAT MERCEDES-BENZ USES TODAY IN DEVELOPING SAFETY.

ercedes-Benz’s pioneering spirit of invention continues. In the year 2000, the brand harnessed much of its technological expertise at the Mercedes Technology

Center (MTC) in Sindelfingen, Germany. Research, development, design, planning, and production are closely integrated. “Interaction between the various areas couldn’t be more intensive or closer. This allows us to reduce development times

and significantly increase the maturity of our products,” explains Prof Dr Thomas Weber, member of the Board of Management of Daimler AG. Many of the approximately 10,000 designers are concerned with safety – tradi-

State of the art: the simulator in Sindelfingen has a 360° screen, a fast electric drive system and provides twelve metres of lateral or longitudinal movement

VIRTUAL ROAD TEST Simulator testing

A realistic driving experience: the simulator allows new assistance systems to be evaluated using ordinary drivers

Pioneering: the first of Mercedes-Benz’s simulators, photographed without projection dome (Berlin, 1985)

Realistically simulating highly dynamic manoeuvres such as changing lane is a particular challenge, along with conducting intensive research into driver and vehicle behaviour on the road. This is where the new driving simulator in Sindelfingen comes in, which has been in action since 2010. The simulator cell is a hexapod mounted on six rail-based moveable supports. Inside there is a complete car, as well as a 360° projection screen. The unit moves electrically at a maximum speed of ten metres per second (36 km/h) and up to twelve metres in a lateral direction so that it is even possible to simulate crossing two lanes.

BASICS DEVELOPMENT TOOLS

2003: in excess of two million elements supply an accurate portrayal of crash processes. Engineers are able to view every detail accurate to the millisecond and to adjust the design accordingly

tionally a key area of competence for the inventor of the automobile. For decades, Sindelfingen was also where Béla Barényi, the “father of passive safety in automobiles”, worked (see page 34). Ideas that the visionary

“ALWAYS EXPECT THE UNEXPECTED” OVER 40 YEARS AGO engineer outlined on paper at that time because of the vastly increased complexity today require elaborate test facilities and methods of calculation to advance them. It is not just many fundamental aspects of the safe automobile that were devel-

oped and brought to series production by MercedesBenz. Many methods and development tools can also be attributed to the company. As part of the process, Mercedes-Benz always focuses on the customer. From the early 1970s onwards, customers have been invited to the test track so that the car maker can observe how they handle the car: “We play a game: ‘Always expect the unexpected’. All people have to do is drive in a straight line at 60 km/h. And to respond. To children playing or unobservant pedestrians. Who suddenly shoot out across the road in the form of dummies. We are interested in what happens

1989: the E-Class W 124 with 25,000 finite elements

NON-DESTRUCTIVE CRASHING Detailed computer simulations

1994: by the time of the E-Class W 210, the computer could handle 75,000 elements

Crash tests are increasingly performed on computer. Starting in the mid-1980s with rough models, this approach now provides detailed insights into exactly what happens when a car deforms in an accident. The polygon mesh for the virtual vehicle structure is now comprised of more than two million tiny rectangles and triangles. Every year, more than 50,000 virtual crash tests are carried out, tying up one of the world’s biggest IT networks: it takes 5000 processors one day to complete the 320,000 million calculations that make up a virtual crash.

2008: simulation provides insights into everything that happens during a crash

BASICS DEVELOPMENT TOOLS

next. This is what we measure. Each driver is accompanied by a range of measuring equipment to record their reactions: do they steer or brake first? Do they floor the accelerator or wrench the vehicle away? We also measure how the vehicle responds to the driver and

THE VEHICLE MUST ASSIST EVEN AN ERRING DRIVER whether it tail-skids, slides or fishtails (not dangerous in the test environment). That is how we ascertain the way in which people consistently respond to certain situations when driving. We have to take this into account when designing our cars in order to compensate for human error. Our way of building

Transparent car: when projected, three-dimensional digital mock-ups allow engineers to analyse how all details and components interact

cars demands this.” This is how an advertisement described the process at the time. Since 1985 trials with test subjects have also been conducted indoors. That is when Mercedes-Benz opened the first driving simulator – developed in-house because, although flight simulators existed at that time, there were none for cars. The new driving simulator at the MTC in Sindelfingen has been operational since 2010. Its purpose remains the same. Normal car drivers are able to approach the physical limits of driving performance with absolutely no danger, providing engineers with invaluable findings on the acceptance and operation of new safety systems. At the same time, engineers are able to test the

Transparent bodies: on the virtual human computer model, biomechanical properties are simulated in detail to examine the loads that occur during the virtual crash test

VIRTUAL DUMMY Biomechanical human model Virtual human models provide a clearer picture of what happens to a vehicle’s occupants in an accident than crash test dummies. ““All the crucial biological features of humans – joints, muscles, tendons, ligaments, bones – can only be simulated in very rough terms with dummies,” explains Dr Hakan Ipek, a safety engineer. “Some “ seated positions, such as when a rear passenger is dozing and the belt does not pass over the pelvis in the correct manner, simply cannot be recreated with a dummy.”

BASICS DEVELOPMENT TOOLS

Contact with no adverse consequences: engineers at Mercedes-Benz use the soft crash target to test assistance systems

systems and components of future models at all phases of development. Another highly advanced test station at the MTC is the “ride simulator”. Programmed with vehicle data and road surfaces from real test tracks,

Repeated accuracy: if a vehicle drives a pre-planned course multiple times, the exact routes followed differ by less than two centimetres over all cycles

IT TOOK 30 YEARS TO THE VIRTUAL CRASH TEST

No driver: the route and manoeuvre are programmed in while robots perform steering, braking and accelerating operations

AUTO PILOT AT THE WHEEL Automatically driven test vehicles Mercedes-Benz was the first manufacturer to use auto pilots on closed test facilities to perform safety-critical manoeuvres, which could not be reproduced with precision by humans. “Automated driving” supports the development, testing and validation of assistance systems, as well as testing airbags for misfiring, for example. This makes it possible to carry out tests at critical limits safely and without endangering developers. The test vehicles are series production vehicles fitted with robots to operate the steering system, accelerator and brake.

the ride simulator allows engineers to “drive” a new Mercedes-Benz model on the test station at even very early stages of a project. Early testing also helps with conceiving the digital prototype. All the car’s components are segmented into a polygon mesh to create a virtual vehicle structure. This is comprised of more than two million tiny rectangles and triangles. As a result, much more precise and detailed deformation analysis is possible than in the 1980s when Daimler-Benz engineers started to work on the vision of virtual crash

BASICS DEVELOPMENT TOOLS

Soft landing for dummies: the current A-Class during a crash test

testing. At that time elements were substantially larger at 25 millimetres. Back then it took a good five days for the mainframe computer to perform the calculation for a crash test simulation. These days, there may be just a day between outputting and inputting extraordinarily complex data. Even the crash test dummy (see page 164) – a symbol of scientific crash testing for 50 years – is slowly approaching retirement. For around 15 years now, Mercedes-Benz has been applying virtual biomechanics. Virtual human models simulate the body’s internal structures. In the analytical model, the body consists of approximately 1400 different materials featuring varying biomechanical properties. For a full simulation, the model will one day consist of millions of finite elements. At present there are only about 100,000. Medical and forensic findings are being incorporated all the time to refine the model.

Roof-drop test: every Mercedes-Benz model must survive a roll-over simulation. This test is not a legal obligation

No matter how sophisticated methods of simulation and calculation become, tests involving real vehicles remain essential. Such testing includes the crash tests

DRIVING ROBOTS AS TEST DRIVERS IN SIM-CITY that Mercedes-Benz has been systematically carrying out for over 50 years, and which are described in more detail in this brochure from page 148 onwards. It may also refer to operational tests at Sim-City, a

special test facility in Sindelfingen for testing assistance systems. Here too, Mercedes-Benz engineers have done pioneering work: the company was the first manufacturer to deploy driving robots. They allow developers to reproduce manoeuvres without putting anyone in danger. Human judgement continues to be a critical factor, though, and real testing with real cars and real testers remains core to the development process. ■

ORGANISED DESTRUCTION Crash testing at Daimler since 1959

Rocket sled accident: the engine did not detach from the test vehicle

The first impact tests carried out by MercedesBenz as early as the late 1950s were spectacular: winches or hot-water rockets were used to propel the cars. Crash tests still form the basis of safety development at Mercedes-Benz. These days, however, vehicles are accelerated by means of a high-tech cable pulley system. Every year some 500 impact tests of this kind are carried out at the development centre in Sindelfingen. Altogether, new Mercedes-Benz passenger cars must pass almost four dozen different crash tests, many of which are not a legal obligation.

Corkscrew: roll-over after driving over a special ramp

BASICS ACCIDENT RESEARCH

SYSTEMATIC ANALYSIS

REALITY IS THE YARDSTICK FOR 45 YEARS THE ACCIDENT RESEARCHERS AT MERCEDES-BENZ HAVE GATHERED INFORMATION ABOUT THE NATURE AND COURSE OF ACCIDENTS, THE DEFORMATION BEHAVIOUR OF BODY STRUCTURES AND THE CAUSES OF INJURIES. THEIR FINDINGS ARE INCORPORATED INTO THE DESIGN OF NEW MODELS, AND PROVIDE A BASIS FOR THE DEVELOPMENT OF REALISTIC TEST PROCEDURES AND STANDARDS.

ednesday, 29 January 1969 was a cold, grey winter’s day. At the Interior Ministry of the state of BadenWürttemberg, government officials and police commissioners came together with representatives from the then Daimler-Benz AG for a conference lasting several hours. On the agenda was

an extraordinary request by the automotive manufacturer: a request for police support during the reconstruction and analysis of traffic accidents involving Mercedes-Benz models. In this way the development engineers sought to obtain findings from real accidents and use them for the further improvement of occupant safety. DaimlerBenz had already gained

some initial experience in this field two years earlier, during a six-month pilot test: from January to June 1967, employees of the company worked together with police personnel to examine serious traffic accidents occurring in the Böblingen area and on the No. 8 motorway. During the conference at the ministry, the company sought to put this research project on a broader and

Like detectives, accident researchers like Roland Krajewski for example establish how well the occupants were protected by the airbags

80 to 100 times each year the accident researchers at Mercedes-Benz are called out to examine serious collisions

“IN ANY OTHER CAR I WOULD PROBABLY NOT BE ALIVE TODAY.” On 9 April 2008 PETER ITEN driving a Mercedes M-Class survived a mass pile-up involving 73 vehicles between Lausanne and Vevey

“THERE WAS VIRTUALLY NO DAMAGE IN THE INTERIOR.” On 20 August 2010 JANA BERGNER in her CLS-Class was overrun by a six-tonne tractor

BASICS ACCIDENT RESEARCH

-35 -20

above all permanent basis. It succeeded: the heads of the relevant police departments once again indicated their willingness to cooperate. An express letter informing other official bodies and requesting assistance was sent out immediately. On 29 April 1969 the accident research project received the official go-ahead. Once a number of details had been clarified, the Interior Ministry using case reference number III 5304/126 decreed that in future, the police stations would inform the car manufacturer by telephone when accidents occurred, and that the representatives of the company

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Lightly injured

-20 -10 0 Reduction of injury risk in percent Study period 2003-2007

Source: GIDAS

DETAILED ANALYSIS Modern assistance systems reduce the risk of injury.

SERIOUS ACCIDENTS WITHIN A RADIUS OF 200 KILOMETRES were able to view the accident files and were permitted to question the officers involved about the incident. The reason given: “The Interior Ministry supports the in-house research activities by Daimler-Benz AG, as they are of general importance for traffic safety.” Thanks to good cooperation with official bodies and police stations, the area covered by Mercedes-Benz accident research was increased several times over the following years. Today it extends from Baden-Baden to Ulm, from Mannheim to Freiburg and from Tauberbischofsheim to Freudenstadt – a radius of around 200 kilometres from Sindelfingen.

Severely injured and dead

In 2009 it was once again demonstrated that Mercedes-Benz drivers are safer on the road with modern assistance systems. This was the result of a study by Mercedes-Benz accident researchers based on GIDAS accident data and a replacement parts survey. Vehicles on the road both with and without a system were included. The results were clear: DISTRONIC PLUS with BAS PLUS and PRE-SAFE ® Brake reduces the risk of being seriously injured or killed in the impacting vehicle by 35 percent during a frontal collision.

Dozens of photos, sketches, measurements and data obtained at the scene help during the systematic reconstruction of a collision

Some 45 years of Mercedes-Benz accident research means 45 years of painstaking investigation and data collation. Nowadays the accident researchers are out and about around 80 to 100 times each year to subject serious collisions to their scientific gaze. Since the formation of the accident

research department, they have examined and reconstructed over 4,200 traffic accidents. The work of the researchers usually begins at the accident scene: How did the accident come about? In what positions were the vehicles after the impact? Are there tyre or skid

marks? How severely was the bodywork deformed? Were the airbag(s) and belt tensioner(s) deployed? Is there anything unusual in the interior of the MercedesBenz model involved in the accident? What injuries were sustained by the occupants? Which driver assistance systems would have helped to

“I AM CONVINCED THAT MERCEDES-BENZ SAVED MY LIFE.” On 10 June 2008 BERND VAN HUSEN suffered only bruises in his C-Class when colliding with a car travelling the wrong way on the A81

“IT’S VERY IMPRESSIVE WHEN YOU SEE THE MERCEDES-BENZ DRIVER GET OUT OF HIS VEHICLE BY HIMSELF AFTER A CRASH LIKE THAT.” DAVID HEINKELE, Böblingen fire service

BASICS ACCIDENT RESEARCH

prevent the accident or mitigate its severity? Question after question, the answers to which are electronically recorded using a tablet PC. Plus dozens of photos, laser scans, sketches and injury reports. When all the information is finally to hand, the collision is systematically reconstructed. The researchers are assisted in this by specialist software which converts the collected data and measurements into moving images. As part of the process, the computer compares for example the length of the tyre or skid marks at the

scene with the engineering and dynamic data of the Mercedes-Benz model involved in the accident, and reconstructs what happened

AROUND 80 PAGES OF ACCIDENT DATA AND MANY PHOTOS as it occurred. On the screen the specialists are then able to establish how the car moved before, during and after the impact. Finally the results are compared with data from other accidents, so that over time the engineers are able

to obtain a precise picture of typical injuries, and findings for the development of new, even more effective protective systems. With the help of a so-called prospective efficiency analysis, the accident researchers are also able to ascertain what the consequences of an accident would have been if a particular safety feature had been on board. Accident research is an important component of the safety philosophy “Real Life Safety” – namely taking the lead from real accidents, not only from laboratory tests alone. ■

Alle Informationen über den Crash werden gespeichert und später für die Computersimulation des Unfallhergangs genutzt

All the information about the crash is saved – in this case by the Head of Accident Analysis, Heiko Bürkle – and used later to reconstruct what happened

“THERE IS SOMETHING TO BE LEARNED FROM EVERY ACCIDENT.” Early investigations: even before systematic accident research took off, Mercedes-Benz engineers took a critical look at cars involved in accidents – here a Mercedes-Benz 300

UWE NAGEL, accident researcher at Mercedes-Benz for over 20 years

“THE MORE INFORMATION WE HAVE, THE BETTER WE CAN PUT THE PUZZLE TOGETHER.” DIRK OCKEL, Head of Accident Research at Mercedes-Benz

BASICS BÉLA BARÉNYI

An eye for detail: Barényi (centre) assesses a vehicle after a crash test. He was Head of Advance Development at Daimler-Benz until 1974

BÉLA BARÉNYI

THE FATHER OF SAFETY VISIONARY ENGINEER BÉLA BARÉNYI (1907-1997) WORKED FOR DAIMLER FROM 1939 TO 1974. HE INITIATED MORE THAN 2500 REGISTERED PATENTS, MANY OF THEM CONCERNED WITH THE PRINCIPLES OF AUTOMOTIVE SAFETY. HE INVENTED THE SAFETY ZONE PROTECTED BY CRUMPLE ZONES.

éla Barényi had groundbreaking ideas early on: during his studies in the 1920s, he worked on a concept for a modern automobile with a tubular backbone chassis and air-cooled, horizontally opposed engine – as subsequently realised by Porsche in the form of the Volkswa-

gen Beetle. From 1939 the engineer dedicated himself to improving passenger car bodies at Mercedes-Benz. This work resulted in a 1941 patent for an improved platform frame which, owing to its particular resistance against distortion, minimised “booming and shaking”. From his studies of motor vehicles based on a cellular design, Barényi developed

the concept of a stiff passenger cell with crumple zones. Daimler-Benz implemented the patent filed in 1951 for the first time on model series W 111 (“Fintail”) of 1959. Crumple zones deform in an accident and absorb the kinetic energy from the collision in a controlled way. At the same time, a sturdy occupant cell protects the vehicle occupants. Since

that time, this structure has become an established part of passenger vehicles worldwide. Barényi’s “safety steering shaft for motor vehicles” also caught on. This technology was patented in 1963 and premièred as a complete safety steering system in the W 123 series of 1976, the predecessor to the E-Class. ■

Lasting legacy: MercedesBenz design engineer Béla Barényi invented the safety body with rigid occupant cell and defined crumple zones. Patented in 1951, this was implemented in the 1959 Mercedes-Benz 220 SE

BASICS EXPERIMENTAL SAFETY VEHICLES

Inflatable metal structures, which give structural components greater stability within fractions of a second, are one of the highlights of the ESF 2009

ESF 2009

EXPERIENCE THE FUTURE THE ESF OF 2009 IS MERCEDES-BENZ’S FIRST EXPERIMENTAL SAFETY VEHICLE SINCE 1974. LIKE ITS HISTORIC PREDECESSORS, IT BRINGS TOGETHER PIONEERING INNOVATIONS IN THE FIELD OF VEHICLE SAFETY WITH INTUITIVE ACCESSIBILITY, MAKING PROGRESS COME ALIVE. SOME OF ITS INNOVATIVE FEATURES, SUCH AS THE BELTBAG, HAVE NOW ENTERED SERIES PRODUCTION AT MERCEDES-BENZ.

BASICS EXPERIMENTAL SAFETY VEHICLES

he experimental ESF 2009 safety vehicle revealed what Mercedes-Benz’s safety experts were researching and working on five years ago. In some respects they were looking many years into the future. Meanwhile, some innovative features have already entered series production: in 2013 the beltbag made its début in the new S-Class, with Interactive Vehicle Communication (see page 178) likewise launching that year. The next step in lighting technology follows this year in the shape of Active Multibeam LED headlights (see page 128). The ESF 2009 was developed and built entirely at the test vehicle workshops in Sindelfingen. This experimental safety vehicle based on the Mercedes S 400 HYBRID features more than a dozen safety innovations. The following five innovations are among the highlights of the ESF 2009:

PRE-SAFE ® structure: the inflatable metal structures save weight or increase the stability of structural components. When at rest, the metal section is in a folded state to save space. If its protective effect is required, a

OFTEN LOOKING MANY YEARS INTO THE FUTURE gas generator builds up an internal pressure of 10 to 20 bar within fractions of a second, causing the section to unfold for significantly more stability. Braking Bag: this auxiliary brake accommodated in the vehicle floor is a new type of component. If the sensors and control unit predict that an impact is certain, the “Braking Bag” is deployed just before the collision and supports the vehicle against the road surface with its friction coating. The vehicle’s brake dive increases the friction and helps to decelerate the vehicle before the impact occurs (see also page 73 of this magazine).

Interactive vehicle communication: the ESF 2009 is able to communicate directly with other vehicles, or via relay stations. Using ad-hoc networks and WLAN radio technology, it is able for example to receive and transmit warnings of bad weather or obstacles in the road. PRE-SAFE ® Pulse: this further development of PRESAFE ® is able to reduce the forces acting on the torsos of the occupants during a lateral collision by around one third. It does this by moving them towards the centre of the vehicle by up to 50 millimetres as a precautionary

MANY VISIONS HAVE BECOME SERIES REALITY measure by inflating air chambers in the seat cushions. A similar system is found in the latest S-Class: with PRE-SAFE ® Impulse, the driver and front passenger are pulled away from the direction of impact by their

seat belts at an early phase of the crash, before the resulting occupant deceleration sets in. Consequently the risk and severity of injuries in a frontal collision are reduced significantly. Spotlight lighting function: this partial LED main beam illuminates potential hazards. If the infrared camera of Night View Assist Plus detects pedestrians in the road, these can be briefly illuminated as if by a spotlight. This feature is now also a reality. Mercedes-Benz is continuing a long-standing tradition with the ESF 2009: safety experts in Stuttgart built more than 30 experimental vehicles for the ESV Safety Conferences held from 1971 to 1975 and subjected them to crash tests to satisfy the ever-visionary safety requirements of MercedesBenz. Four of these experimental safety vehicles were presented to the public, and many of the revolutionary ideas such as ABS or the airbag first entered series production at MercedesBenz. ■

Based on the /8, the ESF 5 (1971) was equipped with driver’s and front passenger’s airbag and, for rear passengers, two airbags in the backrests of the front seats

To protect pedestrians and cyclists the front and rear bumpers of the ESF 13 (1972) have foam side sections and the door handles are rounded

The ESF 22 (1971) had a front-end extension of 15 centimetres with hydraulic impact absorbers. Its equipment included four three-point belts, each with three force limiters and a belt tensioner

With ABS, driver’s airbag, belt tensioners and belt force limiters, the ESF 24 (1974) possessed modern restraint systems. Based on the S-Class (W 116)

BASICS FACTS, FIGURES AND CURIOSITIES

STEERING WHEELS

DID YOU KNOW? 300

KILOGRAMMES The more than 30 experimental safety vehicles (German abbreviation ESF) built by Mercedes-Benz between 1971 and 1974 satisfied the requirements of the US National Highway Traffic Safety Administration (image shows the ESF 21 following an offset impact). However, they had up to 300 kilograms of additional reinforcement on board and proved to be too heavy. A more realistic aim (reducing the impact speed against a rigid barrier from 80 to 65 km/h) and intensive further basic research were tangible outcomes of activities involving experimental safety vehicles.

250,000

EUROS

The first dummies designed specifically for safety tests were used in the USA in 1949 to test ejector seats in jet fighters, and were later adopted by the automotive industry too. However, the first crash test dummies intended specifically for automotive safety research did not appear until the late 1960s. Since that time, dummies have become more and more sophisticated. The latest dummies cost up to 250,000 euros.

From the 1930s onwards, inventor Béla Barényi was preoccupied by steering wheels and steering columns – the main cause of serious and fatal injuries among car drivers. He protected his findings with a series of patents. For a 1976 publication (“Wege zum ausgewogenen Alltagsauto von morgen” – Approaches to the well-balanced, everyday car of tomorrow), Barényi analysed 60 of the steering wheels available on the market and reached a harsh conclusion: “A good 90 percent of all steering wheels presently used in global car manufacturing are outright criminal instruments.” He goes on to say: “Appalling injuries arise from relatively harmless front-end collisions because the steering system can penetrate the vehicle interior… and measures known about for decades… have not been applied.”

1,500 SIMULATIONS

In the year 2000, the 203 model series was one of the first cars for which crash test simulations played a serious part in development. More than 1500 simulations were carried out. The successor unveiled in 2007 was the first series production car in the world to be developed using the trend-setting digital prototype (DPT) method. This made it possible for all simulation methods to be pooled for the first time, and thus to create a completely virtual car. As well as the high speed of development, the decisive advantage that computer simulation has over real crash tests lies not only in the fact that the vehicles are not destroyed; even more important than that is the ability which engineers have to detect and follow what actually happens in an impact in great detail.

4,200 ACCIDENTS

As early as 1969, Daimler started to systematically examine real accidents involving Mercedes-Benz passenger cars, with colleagues on the truck side following a year later. The researchers went out up to one hundred times a year to meticulously document and analyse accidents. This included looking at aerial photographs. The database now extends to more than 4200 road traffic accidents.

Photo: Herbert Spichtinger/Corbis

PRE-SAFE

IN 2002 MERCEDES-BENZ BEGAN A NEW ERA IN VEHICLE SAFETY WITH THE PREVENTIVE OCCUPANT PROTECTION SYSTEM

PRE-SAFE速. PRE-SAFE

速

ABLE TO ACTIVATE PREVENTIVE SAFETY MEASURES FOR CAR OCCUPANTS. THE AIM IS TO PREPARE THE CAR AND ITS OCCUPANTS FOR AN IMPENDING IMPACT, SO THAT IF IT OCCURS, THE SEAT BELTS AND AIRBAGS CAN FULFILL THEIR PROTECTIVE FUNCTION TO THE FULL. 42

NINE LIVES CATS are true survival experts: even if they fall from considerable heights, their visual sense and fine balance go into action instantly to make sure that they land on their paws

PRE-SAFE BASIC FUNCTIONS

PRECAUTIONARY SAFETY MEASURES

CAR WITH PROTECTIVE REFLEXES PRE-SAFE 速 ENTERED SERIES PRODUCTION AT MERCEDES-BENZ OVER TEN YEARS AGO. THE PROTECTIVE MEASURES OF THE FIRST GENERATION: WHEN THE CAR REGISTERS A CRITICAL DRIVING SITUATION WITH THE HELP OF THE ESP速 SENSORS, THE FRONT SEAT BELTS ARE TENSIONED AS A PRECAUTION, THE FRONT PASSENGER SEAT WITH MEMORY PACKAGE (OPTION) IS MOVED TO A MORE FAVOURABLE POSITION FOR AN IMPACT AND THE SLIDING SUNROOF IS AUTOMATICALLY CLOSED.

Arrows point to the basic functions of PRE-SAFE 速, in this case using a C-Class (W 204) of 2006 as an example: The front seat belts are tensioned as a precaution (red arrows), the side windows and sliding sunroof are closed (blue) and the electrically adjustable front passenger seat is brought into a more favourable position for a crash (orange).

PRE-SAFE BASIC FUNCTIONS

ver ten years after the world premiere of the preventive occupant protection system PRE-SAFE ® in the S-Class (W 220) in autumn 2002, PRE-SAFE ® is available in 16 model series throughout the model range of MercedesBenz Cars, from the A- to the S-Class, and can currently take preventive measures in up to 13 scenarios where accidents occur most. More than half of all MercedesBenz passenger cars delivered worldwide in 2013 were equipped with PRE-SAFE ® as standard. In the new S-Class, Mercedes-Benz has extended the PRE-SAFE ® system with new functions (see next double-page). There are no statistics to show how many lives

PRE-SAFE ® has helped to save in the meantime, or how many injuries it has helped to prevent or minimise. However, analyses carried out by Mercedes-Benz accident research have

AVAILABLE IN A TOTAL OF 16 MODELSERIES shown that more than twothirds of all traffic accidents are preceded by critical driving situations which enable conclusions to be drawn about risks or impending collisions. PRE-SAFE ® is therefore a significant element of the holistic safety concept by Mercedes-Benz known as “Real Life Safety”. Analyses performed during crash tests show just how important and effective

THE HISTORY of PRE-SAFE ®:

2002

Introduction in the S-Class (W 220); functions: preventive tensioning of the front seat belts, better positioning of the power-adjustable front passenger seat, automatic closing of the sliding sunroof (optional)

2005

combination with Brake Assist PLUS; extended functions: automatic closing of the side windows, inflation of side bolsters on multicontour front seats (optional)

2006

PRE-SAFE ® activation by additional assist systems with radar technology

2011

Debut in the compact class (B-Class W 246)

2013

Introduction of new functions in the S-Class: PRE-SAFE ® PLUS and PRE-SAFE ® Impulse (see next double-page), networking with stereo camera

anticipatory occupant protection can be. Take seat belt tensioning, for example: because the precautionary measures mean that the driver and front passenger are held in their seats in the best possible position, and so do not move forward as much prior to the impact as a result of emergency braking, the loads exerted are correspondingly reduced. These tests have shown that the head of a dummy is subjected to around 30 percent less stress, while MercedesBenz engineers have recorded a reduction of around 40 percent in the neck area. PRE-SAFE ® is able to activate preventive safety measures for car occupants. The aim is to prepare the car and its occupants for an impending impact, so that if it occurs, the seat belts and airbags can fulfill their protective function to the full. PRE-SAFE ® protective measures are reversible: if the accident is averted, the advance tensioning of the seat belts is reversed automatically and the occupants are able to reset the positions of the seats and the sliding sunroof. The anticipatory occupant protection system is then immediately ready for action again. PRE-SAFE ® is for example activated in the event of emergency or panic braking, severe oversteer or understeer, critical steering manoeuvres or activation of Brake Assist. Early detection of an accident is possible because PRE-SAFE ® is networked with the Brake Assist and ESP ® systems.

Two thirds of all accidents are preceded by critical driving situations, according to analyses by Mercedes-Benz accident researchers

Their sensors detect potential critical driving situations and send appropriate information to the electronic control units within milliseconds. When installed in combination with DISTRONIC

PLUS, PRE-SAFE ® also uses the information provided by the short-range radar sensors in the front bumper to tension the front seat belts at the very last moment before an unavoidable collision, thus reducing the forces

exerted on the driver and front passenger during a crash. This PRE-SAFE ® function is literally the “ultima ratio” of anticipatory occupant protection, since the impact occurs around 150 milliseconds later. ■

THE FOLLOWING ARE THE PREVENTIVE MEASURES INITIATED BY PRE-SAFE ® PRE-SAFE ® in situations with critical longitudinal dynamics

PRE-SAFE ® in situations with critical lateral dynamics**

The driver and front passenger seat belts are tensioned

The side windows are closed, leaving only a small gap

The fore-and-aft setting and height plus the cushion and backrest angle of the front passenger seat* are brought into a more favourable position for an accident

The sunroof* is closed, leaving only a small gap

The bolsters in the seat cushions and backrests of the multicontour front seats* are inflated *if fitted in the vehicle concerned **in addition to the emergency braking measures

PRE-SAFE NEW FUNCTIONS

FOCUS ON FOLLOWING TRAFFIC

CAR WITH ALL-ROUND VISION THE NEW PRE-SAFE ® FUNCTIONS CAN HELP TO PREVENT

PRE-SAFE ® IMPULSE Temporary decoupling of occupants PRE-SAFE ® Impulse: at an early phase of the crash, before the resulting deceleration sets in, the front occupants are pulled away from the direction of impact and deeper into their seats by their seat belts.

REAR-END COLLISIONS IN CITY TRAFFIC, DEFUSE DANGEROUS SITUATIONS CAUSED BY TRAFFIC BEHIND AND ENHANCE THE PROTECTION OFFERED BY THE SEAT BELTS.

RE-SAFE® PLUS extends the familiar occupant protection measures to include hazardous situations with following traffic. A radar sensor in the rear bumper monitors the traffic following behind the

indicates a wish to remain stationary (for example by keeping the brake pedal depressed, activating the HOLD function or engaging transmission position “P”), PRE-SAFE ® PLUS provides support if the collision danger persists by increasing the brake pressure. The

car. If an impending rearend collision is recognised, the driver of the vehicle following behind is warned by high-frequency (5 Hz) flashing of the rear hazard warning lamps (not for vehicles with country code USA/ Canada). When the car is at a standstill and the driver

PRE-SAFE ® PLUS Occupant protection in case of impending rear-end collisions If the danger of a collision persists, PRE-SAFE ® PLUS can support the driver by increasing the brake pressure. The vehicle’s brakes are “locked”, which also reduces the danger of secondary impacts

Activation of rear hazard warning lights at a higher frequency

Activation of PRE-SAFE ®

2 Rear collision is detected

The vehicle is kept firmly braked

vehicle’s brakes are “locked”. Immediately before impact, the PRE-SAFE ® anticipatory occupant protection measures, especially the reversible belt tensioners, are also deployed. Keeping the vehicle firmly braked when another vehicle hits it from behind greatly reduces the risks to the occupants, such as that of whiplash injuries. At the same time, it serves to protect other road users by restricting uncontrolled vehicle movements after the initial impact that could lead to secondary collisions, such as being shunted into a vehicle in front or colliding with pedestrians or other road users at junctions. Mercedes-Benz is extending the front seat belt’s protective function with the introduction of PRE-SAFE ® Impulse: at an early phase of the crash, before the result-

ing deceleration sets in, the front occupants are pulled away from the direction of impact and deeper into their seats by their seat belts. By the time the accident enters the phase when loads peak, the extra distance they are retracted by can be used

BRAKE LOCKING PREVENTS SECONDARY IMPACTS while dissipating energy in a controlled fashion thanks to additional force limiting in the belt buckle. Pre-acceleration and force limitation allow the occupants to be temporarily isolated from the effects of the crash. Consequently the risk and severity of injuries in a frontal collision are reduced significantly. With PRE-SAFE ® Impulse, the seat belt strap can be retracted by pyrotechnical means at all three belt an-

chorage points, both in the pelvis and chest area, and released again with controlled force at the buckle and in the shoulder area. The fundamental difference compared to conventional belt tensioners is that the force for retracting the belt strap is maintained more consistently for a much longer time. The deployment logic fires the seat belt system’s belt tensioners progressively depending on the seriousness of the accident. In this way, the tensioning force can be adapted as required. The PRE-SAFE ® Impulse system is integrated into the seat’s structure and supplements the pyrotechnical reel tensioner with a pyrotechnical buckle and anchor fitting tensioner including a central gas generator. ■

PRE-SAFE INTERVIEW Group portrait with dummies: Mercedes-Benz safety experts Prof Rodolfo Schöneburg, Michael Fehring and Karl-Heinz Baumann in the dummy laboratory

ercedes-Benz engineers Prof Rodolfo Schöneburg (54) and Karl-Heinz Baumann (62) were instrumental in the development of PRE-SAFE® from the initial idea through to its readiness for series production. Prof Schöneburg is head of the Safety, Durability and Corrosion Protection Center at Mercedes-Benz Cars. In addition to his honorary professorship at the Dresden University of Applied Sciences, Prof Schöneburg also holds various other distinctions, including the renowned “Pathfinder Award” from American safety association the “Automotive Safety Council” and the “Gold Diesel Ring” from the German Association of Automotive Journalists (VdM). Mr Baumann worked for Mercedes-Benz for 35 years. The many innovations developed under his direction include the automatically extending roll-over bar on the SL from the R 129 model series, the ellipsoid bulkhead concept on the SLK from the R 170 model series and the tridion safety cell on the smart. As Mr Baumann’s successor, Michael Fehring (48) heads the Passive Safety Concepts and Strategies department. Prior to this, he was f. i. project director for the ESF 2009 experimental safety vehicle, which incorporated numerous PRE-SAFE® innovations.

PROF RODOLFO SCHÖNEBURG, MICHAEL FEHRING, KARL-HEINZ BAUMANN

“USING VALUABLE TIME” A DISCUSSION WITH THE ORIGINAL BRAINS BEHIND PRE-SAFE®

Mr Baumann, is it true that your daughter had a biology book with a picture of a cat dropping to its feet? Or is it just a popular myth that this inspired you to evolve the idea of a car with reflexes – as the fundamental idea behind PRE-SAFE®? Baumann (laughs): Well, to be precise it was actually a Mickey Mouse comic book. I asked my daughter, who was eight at the time, how she would illus-

trate the fact that every living being reacts reflexively to sudden dangers. In response to which, she showed me her comic with a drawing of a cat. The comic still exists, by the way, and has even been exhibited on several occasions as part of Mercedes-Benz’s touring exhibition “Prepare to be safe”. How did you come up with the idea of also utilising the time prior to a crash

for safety measures - this being the radically new aspect of PRE-SAFE®? Schöneburg: As with so many Mercedes-Benz safety innovations, the decisive impulse that triggered the development of PRE-SAFE® was real-world crashes. These revealed that the symptoms of an impending accident are frequently manifested before the actual collision. This means that valuable time used to be lost when the protection systems were only activated once a collision had occurred.

PRE-SAFE INTERVIEW

PRE-SAFE® makes use of this time, from initial identification of a driving situation harbouring crash potential to an actual collision, in order to provide the occupants with preventive protection. In what sort of time dimensions are we talking here? Schöneburg: An accident occurs within around 100 milliseconds. If you drive into a wall at 50 km/h, for example, around 0.1 seconds elapse before the car comes to a standstill, i.e. within 100 milliseconds everything must be activated and the occupant must be contained by the seat belt and airbag. But when we use the pre-accident phase with PRE-SAFE® we have not just milliseconds of time, but seconds. This enables us to bring the backrests into an upright position and to tension the seat belts as well. PRE-SAFE® was introduced into series production in the S-Class back in the autumn of 2002. When did you begin the development process? Schöneburg: When I joined MercedesBenz in 1999, I took a look at the various safety departments. The PRESAFE® concept was presented to me for the first time by Mr Baumann and his staff. In the same year we established a PRE-SAFE® steering committee comprising staff from the two areas of Active Safety - that is, accident prevention - and Passive Safety. We held regular meetings to coordinate and push ahead with the development of the sensor systems and triggering algorithms while at the same time developing the actuators in the vehicle, in particular the reversible belt tensioners. Baumann: The really interesting aspect here was that the areas of Active and Passive Safety, which had been working relatively independently of one another for many years, came together to work on this innovation, with each area benefiting from the collaboration. Mercedes-Benz had once defined Active

and Passive Safety as separate areas, which was very important in specifying the respective tasks. It was equally logical for us to merge the twoin view of our integral safety strategy at a subsequent juncture. What were the biggest obstacles in developing PRE-SAFE® to production readiness? Schöneburg: First of all, I think the greatest achievement was the idea itself. For many years there was a mental block on the subject of pre-crash. The general view was that it needed to be one hundred percent certain that an accident would occur before features such as the airbags could be activated. The mental leap was the insight that absolute certainty that an accident will happen will probably never be attainable. That we need to work on the basis of the probability of an accident, and that we therefore need to concern ourselves with reversible systems, as there is always a possibility that it may be possible to avoid an impending accident. I believe that was the essential innovation! How were the PRE-SAFE® systems tested? Schöneburg: We carried out in-depth testing of PRE-SAFE® at test sites, in road traffic and in the simulator, of course. In order to optimise the system’s capacity to identify situations, during development of the second generation, when we combined PRE-SAFE® with the information from DISTRONIC PLUS, the new technology was installed together with additional measuring equipment in taxis, for example. In 2007 these vehicles covered over 400,000 kilometres in Stuttgart city traffic. Dense stop-and-go traffic, fast and frequent lane-changes plus varying road surfaces with potholes and manhole covers provided ideal condi-

tions for us to verify the algorithm. Because a kerb close by or radar reflections from tram rails must not lead to activation of the occupant protection systems, of course. In contrast to the seat belt, is it right to say that PRE-SAFE® had no problems gaining acceptance among drivers right from the outset? Fehring: Absolutely, indeed acceptance tests in the driving simulator and on the road have shown that the PRESAFE® systems actually enhance the passengers’ feeling of safety. This is attributable to the way in which they are firmly held in place in the vehicle in critical situations. Another finding was that the test persons reacted with greater alertness in the various dangerous situations when the belts tightened. Is it possible to put a figure on how many lives PRE-SAFE® has saved since it was introduced 12 years ago? Fehring: There are no statistics to show how many lives PRE-SAFE® has helped to save in the meantime, or how many injuries it has helped to prevent or minimise. However, analyses carried out by our accident research team have shown that more than two-thirds of all traffic accidents are preceded by critical driving situations which enable conclusions to be drawn about risks or impending collisions. Example crash tests conducted in the course of the development process additionally showed that PRESAFE® can reduce the risk of serious injury in frontal impact circumstances by up to a quarter. The PRE-SAFE® system in the new S-Class covers around a dozen accident scenarios. Are any further PRESAFE® innovations conceivable? Schöneburg: Inside and outside of the company, the wealth of safety features that we have in our series production vehicles today may have given rise to the impression that not a great deal

“Mercedes-Benz aims to remain the trend-setter in the field of safety.” KARL-HEINZ BAUMANN

more is to be expected here. This perception is wrong – we have a whole host of ideas aimed at further improving vehicle safety. Fehring: Take our ESF 2009 experimental safety vehicle, for example this featured various PRE-SAFE® innovations which we are currently developing to production standard. In concrete terms, what will the next PRE-SAFE® innovation be? Schöneburg: We are currently concentrating on reducing the strain on the upper torso in a side-on collision. Doesn’t that go by the name of PRESAFE® Pulse on the ESF 2009? Fehring: Exactly. We aim to reduce the strain on the upper torso by gently nudging the occupants towards the

centre of the vehicle as a preventive measure. This creates additional space for even more effective deployment of the side airbag. Occupant preconditioning as a whole appears to be a major topic in the area of PRE-SAFE®? Fehring: Yes. The PRE-SAFE® belt tensioner, for example, can prevent occupants from moving too far forward in emergency braking or their torso from swaying too far to the side in the event of skidding as a result of belt slack. Tests with Mercedes-Benz passenger cars show that the belt tensioner is able to reduce substantially such unintentional displacement of occupants. Schöneburg: Another component is automatic seat priming. Our accident

research specialists have established that a very strongly inclined backrest or a seat cushion in a flat position can impair passenger retention in an accident. This is often the case on the front passenger’s side. When the PRE-SAFE® sensors detect an impending collision, the seat cushion inclination is automatically increased on the front passenger’s side and the backrest is moved into a position enabling the airbag and seat belt to be deployed to maximum effect. To date, the PRE-SAFE® systems have been reversible. Is it at all conceivable that non-reversible PRE-SAFE® ideas such as the PRE-SAFE® Structure on the ESF 2009, that is, inflatable metal structures, might be introduced into series production?

PRE-SAFE INTERVIEW

“We still have plenty of ideas for further improving vehicle safety.”

“PRE-SAFE® systems actually enhance passengers’ subjective feeling of safety.”

PROF RODOLFO SCHÖNEBURG

Schöneburg: This is a difficult matter, because non-reversible systems only make sense when an accident can be forecast with 100 percent certainty. And sometimes it is still possible to prevent an accident in the final second. But we are working on it, and we see potential in the intelligent networking of sensors. The vision of accident-free driving has become established as a buzzword. It no doubt serves to spur on the safety experts at Mercedes-Benz to keep making cars safer step by step. But isn’t it true to say that as long as people are involved in road traffic, mistakes will always be made and accidents will happen? Schöneburg: The vision of accident-free driving has probably been around as long as the car itself has. And of course it provides an incentive to set ourselves ambitious targets. But if you look beyond the marketing ef-

forts, the vision of accident-free driving remains just that: a vision. Of course we continue to put every effort into further reducing the number of accidents as well as the severity of injuries incurred, using new safety technologies and our own company accident research, but there’s no point in promising the impossible. The simple fact is that people make mistakes – including and even especially when they’re behind the wheel of a car. Thanks to new, affordable camera and sensor technology and sensor fusion, assistance systems have undergone an innovation push in recent months. In the light of the CO2 debate and cost pressures, is it not possible that the onus might shift away from passive safety, according to the motto “Now that accidents can be avoided so effectively with assistants we can do

MICHAEL FEHRING

without structural reinforcements and restraint systems, saving weight and fuel in the process”? Schöneburg: No, I don’t fear any such “decontenting”. As Mr Fehring said, around two thirds of all traffic accidents are preceded by critical driving situations. Conversely, this means that a third of accidents are not foreseeable or arise so spontaneously that there is not sufficient time to avoid a collision. And it goes without saying that we must also cover these cases, with robust or energy-absorbing body structures and state-of-the-art restraint systems. We must not forget that traffic accidents will go on happening into the foreseeable future, as for the time being vehicles will continue to be operated by human beings and it will take a long time for driver assistance systems and automated driving to penetrate the market. That is why Mercedes-Benz will be adhering in future to its safety strategy aimed at ensuring compliance

with legal requirements, attaining top marks in ratings and continuing to reinforce the “Real Life Safety” concept. The high level of importance which Mercedes-Benz will continue to attach to passive safety in future is also demonstrated by the construction of the new crash building, which will go into operation in 2016 – three times as large as the old building and equipped with three crash lanes as opposed to the current single lane, to enable testing of all types of crash configurations. As with ABS or ESP®, other manufacturers have since followed safety pioneer Mercedes-Benz and developed preventive safety systems similar to PRE-SAFE®. Does that annoy you? Schöneburg: On the contrary. After all, this is ultimately to the benefit of all road users. Many safety innovations which were first introduced onto the

market by Mercedes-Benz are now also available from other automotive manufacturers. An aspect that is particularly important to me is that PRE-SAFE® is not reserved exclusively for the top models from Mercedes-Benz, but is currently available in a total of 16 series covering the entire model range, from the A- to the S-Class. Baumann: Mercedes-Benz aims to retain its trend-setting, trail-blazing role in the field of safety. If the other manufacturers choose to follow this trail, I see this as an affirmation of our pioneering work.

window bags everything worked just fine. All passengers were protected very well. Fehring: Sure, in a critical braking situation on the motorway with my family. A truck suddenly pulled out onto the overtaking lane and I had to reduce my speed briskly. The reversible belt tensioners did a great job containing my wife and myself. My children in the rear felt the forward displacement and the sudden stop more keenly in their seat belts, however. So there is certainly still potential for further improvements…

Have you ever found yourselves in a critical situation in which PRE-SAFE® saved you from graver consequences? Schöneburg: Yes indeed. I vividly remember an incident while on winter test drives in Sweden. The colleague at the wheel veered of the glazed-over road. PRE-SAFE® was activated, and from the seat belt tensioners to the

Mr Baumann, you have been in retirement since 2012. Do you still keep up with developments? Baumann: Absolutely. I am still in close contact with my Mercedes-Benz colleagues and continue to follow the topic of PRE-SAFE® and vehicle safety in general with great interest. ■

PRE-SAFE DEMONSTRATOR

REALISTIC IMPRESSION

TAKEN FOR A RIDE FORTUNATELY MOST DRIVERS NEVER FIND THEMSELVES IN A SITUATION WHERE THEY EXPERIENCE PRE-SAFE ®. THE PRE-SAFE ® DEMONSTRATOR CONVEYS A REALISTIC IMPRESSION OF HOW THIS ANTICIPATORY SAFETY SYSTEM WORKS.

he simulator uses a linear motor to accelerate the vehicle cabin to up to 16 km/h within a distance of four metres. This corresponds to twice the earth’s gravity acceleration, i.e. twice freefall speed. After around 1.2 seconds the cabin impacts the specially designed hydraulic shock absorbers. In the interim the

VARIOUS TRIP PROFILES CAN BE PROGRAMMED

real S-Class Saloon whose right-hand rear area including the seat were adopted. To keep the Demonstrator compact, the left side, the front of the passenger compartment, the engine compartment and the rear end from the C-pillar to the rear were removed. Specially designed plastic components close off the cabin at these points. The linear drive of the PRE-SAFE ® Demonstrator, which is similar to that of the Transrapid train system,

has a power consumption of 10 kW, is freely programmable and also works in the opposite direction. This enables various acceleration profiles, and also a rear-end collision, to be demonstrated. The cabin can also be rotated by 30 degrees around its vertical axis on its sledge to simulate an oblique impact. If the cabin is rotated by 90 degrees, the drive system can be programmed to produce to-and-fro motion that gives the impression of taking corners at high speed. ■

occupants experience the effects of the PRE-SAFE ® functions at first hand, e.g. belt pretensioning, PRESAFE ® PLUS and the restraining effect of the seat belts during the impact. They can also try out how the new belt buckle extender (see page 78) works. The moving mass of the Demonstrator is 500 kg. This includes the cabin, which was created from a

A trip in the rear of the new S-Class is simulated in the current PRE-SAFE ® Demonstrator. It enables the effects of this anticipatory safety system to be experienced at first hand

DEMO-TOUR around the world In 2009 the prototype construction department at MBtech Group GmbH developed and built the PRE-SAFE ® Demonstrator on behalf of Mercedes-Benz accident research. Originally it simulated PRE-SAFE ® functions on the front passenger side. In 2013 the cabin was reconfigured so that the preventive protection measures are experienced in the rear of the new S-Class. The Demonstrator weighs a total of around 2.5 tonnes, and is designed to be easily loaded onto a vehicle by fork-lift truck. The unit has hydraulically extendable rollers to allow precise placement at the destination. The Demonstrator is used around the world – for example, it has been in Australia as part of the “Safety” roadshow and in Canada for the trial driving presentation of the new S-Class. The cabin of the PRE-SAFE ® Demonstrator can be accelerated to up to 16 km/h by the linear motor

PRE-SAFE FACTS, FIGURES AND CURIOSITIES

DID YOU KNOW? 14

KILOMETRES

In order to optimise the recognition of situations, the new technology with the necessary measuring equipment was installed in taxis during the development phase when PRE-SAFE ® was enhanced with DISTRONIC PLUS. In 2007 these vehicles covered over 400,000 kilometres in Stuttgart city traffic. Dense stop-and-go traffic, fast and frequent lane-changes plus varying road surfaces with potholes and manhole covers provided ideal conditions for the developers to verify the algorithm.

3.5

KILOGRAMMES When the reversible belt tensioners are activated as a precaution by PRE-SAFE ®, the feeling for the driver and front passenger is as if a weight of approx. 14 kg has been hung from the belt strap. Incidentally, it is possible to ascertain how often the belt tensioners have been activated. This is because counters installed in the belt tensioners reveal how often the belt has been tensioned. Two to four precautionary tensionings per 10,000 kilometres are seen as normal. But if a car with this mileage has already recorded 300 or 400 tensioning processes, the Mercedes-Benz experts can be fairly sure that its owner has absolved at least one driver safety training course with it.

2010 For its preventive occupant protection system PRE-SAFE ® , Mercedes-Benz was one of the first automobile manufacturers to receive the “Euro NCAP Advanced” award introduced in 2010 to supplement the five-star rating scheme. Euro NCAP gives this accolade to systems that provide a “scientifically proven safety benefit” but are not yet included when calculating the ratings.

400,000

DEGREES

Occupants sitting upright are more efficiently restrained by the belt, and will meet the airbag at a better angle and time when it deploys. In the 2003 S-Class PRE-SAFE ® uses the electric actuator motors to reposition the front passenger seat. Fore-and-aft adjustment takes place at a speed of 22 millimetres per second, and the backrest angle is altered by 3.5 degrees per second.

120

MILLISECONDS

The powerful electric motor needs hardly longer than the blink of an eye to tension the belt. Forward displacement of the passenger can be reduced by up to 150 millimetres by the reversible belt tensioner (photo), which was used for PRE-SAFE ® for the first time.

SOFTLY.

OF INJURY TO VEHICLE OCCUPANTS. AGE-COM-

OCCUPANTS FROM BEING SUBJECTED TO EXCES-

CHILD SEATS IDEALLY PROTECT YOUNG PASSENGERS. AIRBAGS ARE ABLE

PATIBLE

TO ABSORB HEAD AND BODY IMPACT RELATIVELY

SIVE ACCELERATION RATES IN AN ACCIDENT, OR IN EXTREME CASES EVEN BEING THROWN FROM

Photo: Mitsuaki Iwago/Minden Pictures/Corbis

RESTRAINT AINT SYSTEMS

SEAT BELTS ARE ABLE TO PREVENT

RESTRAINT SYSTEMS HELP TO REDUCE THE RISK

THE VEHICLE.

MOBILE NURSERY BABY KANGAROOS are born early and finish their development in the safety of their mother’s pouch. Only at around six months will the young kangaroo venture out into the world, but immediately withdraw back into the pouch at the slightest sign of danger

RESTRAINT SYSTEMS CHILD SEATS

TAILOR-MADE SOLUTIONS

SMALL PASSENGERS, GREAT NEED FOR PROTECTION IN AN ACCIDENT, THE RISK OF INJURY TO IMPROPERLY SECURED CHILDREN IS SEVEN TIMES HIGHER THAN IF THEY ARE PROTECTED BY RESTRAINT SYSTEMS. THIS IS BECAUSE THE USUAL INERTIA-REEL SEAT BELT IS NOT IDEAL FOR CHILD PROTECTION IN A CAR. FOR ANATOMICAL REASONS, VERY YOUNG PASSENGERS REQUIRE TAILOR-MADE RESTRAINT SYSTEMS. CHILD SEATS NEED TO MEET VARYING REQUIREMENTS DEPENDING ON AGE GROUP, SIZE AND BODYWEIGHT.

RESTRAINT SYSTEMS CHILD SEATS

head of a newborn child accounts for around one quarter of its bodyweight, but only 18 percent for an adult. The bone structure is also different. The logical conclusion: children need restraint systems that are precisely tailored to their age group, size and weight. MercedesBenz offers an infant seat and removable child seat models for children of different sizes. The legal requirements for child seats applicable in Europe are laid down in ECE regulation no. 44. This

hildren are the most vulnerable road users – and not only when travelling by scooter, bicycle or on foot. Because kids who are not adequately secured as car passengers are in great danger if an accident occurs. Their risk of being seriously or fatally injured is seven times higher than for children who are protected by suitable restraint systems. In Germany in 2012, 10,356 children and adolescents aged under 15 years

divides the areas of application into groups (see table). In parallel with this, the first child seats following the new I-Size standard are expected to be available from 2014. One of the re-

quirements of this standard is side impact tests and tests with the more sensitive Q-dummies – both are already included in the stringent in-house requirements at Mercedes-Benz. ■

WHICH SEAT FOR WHOM? ECE group

Body weight

Age

Group 0

up to 10 kg

ca. 9 months

Group 0+

up to 13 kg

ca. 18 months

Group I

9 to 18 kg

ca. 8 months to 4 years

Group II

15 to 25 kg

ca. 3 to 7 years

Group III

22 to 36 kg

ca. 6 to 12 years

A SUITABLE SEAT FOR EVERY AGE GROUP were injured in passenger cars involved in accidents, and 34 killed, according to figures from the Federal Statistical Office. A study published by the technical inspection organisation Dekra in May 2013 came to a shocking conclusion: almost one in ten children in Germany are either unsecured or inadequately secured when in the car. For its study Dekra examined the restraint systems for adults and children in around 20,000 vehicles throughout Germany. The fact that an adult seat belt is not ideal for child protection is due to the peculiarities of a child’s anatomy. This is because adults and children not only differ in size and weight, but also in physiology and physical proportions. For example, the

CHILD SEAT RECOGNITION AND ISOFIX Preventing incorrect operation

To give the best protection to the vulnerable neck vertebrae of an infant, infant seats are installed against the direction of travel

If a child seat is mounted on the front passenger seat, the seat’s airbag must be deactivated. Many car manufacturers have systems using the ignition key for deactivation. There is a problem with this: manual reactivation of the front passenger airbag is often forgotten when removing the child seat, which can seriously endanger adults during an accident. Mercedes-Benz has considerably reduced the risk of such incorrect operation. Because since 1997, Mercedes-Benz models have been optionally or regularly equipped with automatic child seat recognition. An aerial integrated into the front passenger seat sends out signals. Individual child seat models in the Mercedes-Benz accessories range are equipped with transponders which recognise these signals and send back a response. The automatic child seat recognition system then deactivates the front passenger airbag. When the child seat is removed, the front passenger airbag is automatically reactivated. Even more flexibility is possible with the automatic child seat recognition of the new C-Class, which dispenses with a transponder and uses a weight-sensitive mat. This means that any child seat can be used. Installation errors with child seats are prevented by Isofix. This internationally standardised attachment system - which is standard equipment for the outer rear seats of all Mercedes-Benz passenger car models - also optimises protection thanks to a fixed connection between the child seat and the vehicle.

The sensor system for the front passenger airbag of the new C-Class is able to recognise any installed child seat. The airbag is then automatically deactivated, and reactivated when the child seat is removed

In addition to meeting legal requirements, Mercedes-Benz child seats must pass in-house tests such as a frontal impact at 64 km/h

RESTRAINT SYSTEMS AIRBAGS

The driver airbag deploys within a few milliseconds during a severe frontal impact

HARD IMPACT, SOFT LANDING

BLOW UP THE AIRBAG ENTERED SERIES PRODUCTION AT MERCEDES-BENZ OVER 30 YEARS AGO. SINCE THEN THIS RESTRAINT SYSTEM HAS UNDERGONE CONTINUOUS IMPROVEMENTS: NEW TYPES OF AIRBAG THAT ALSO PROTECT DURING SIDE IMPACTS, AS WELL AS ADAPTIVE SYSTEMS THAT RESPOND ACCORDING TO THE SEVERITY OF AN ACCIDENT, WERE INTRODUCED.

n March 1981 MercedesBenz was the worldâ&#x20AC;&#x2122;s first automobile manufacturer to present the airbag and belt tensioner to the public as restraint systems in a series production car. With the debut of the 126series S-Class, MercedesBenz began the gradual

introduction of the airbag as a Passive Safety feature into the entire passenger car range: by 1982 the airbag and belt tensioner were already available as an optional extra for all MercedesBenz passenger cars. By 1992 the driver airbag was standard equipment in all Mercedes-Benz models, the front passenger airbag fol-

lowed as a standard safety feature in 1994, and afterwards Mercedes-Benz realised numerous other applications for airbag technology. Research into the airbag began as early as 1966 at Mercedes-Benz, and practical trials began in 1967. This was a response by the company to the heavy increase in accident figures during

RESTRAINT SYSTEMS AIRBAGS

AIRBAG How the cushion works

the 1960s. Research into the new restraint system was given a further impetus by a plan in the USA to prescribe an automatic occupant protection system for every car from 1969 onwards. Airbags were seen as a very promising technology with which new legal requirements could be met. The principle of the airbag that protects the driver and passengers in an accident was already patented in the 1950s. The pioneers were above all the German Walter Linderer (patent no. DE 896312 of 6 October 1951) and the American John W. Hedrik (patent no. US 2649311 of 18 August 1953). For more than ten years the “inflatable container in a folded state, which automatically inflates in cases of danger” (Linderer’s description of his invention in the patent application) now became an object of research with the aim of achieving series production maturity. The work by Mercedes-Benz engineers and their colleagues employed by other automotive brands and suppliers in the 1960s was initially just funPatent: as early as 23 October 1971, the then Daimler-Benz AG patented the airbag – as an “impact protection device”. The mathematical calculations followed much later

damental research. This is because technology with which the idea from the 1950s could be realised in a passenger car did not exist. Especially the necessary sensors and gas generation continued to pose a serious challenge for the engineers. When American manufacturers began to deliver the first test car fleets with compressed air operated airbags, which were conceived as an alternative to the seat belt, these restraint systems sometimes led to serious in-

Airbag: folded tightly and lubricated against conglutination by talcum powder, the airbag made out of Nylon texture is stowed within the steering wheel boss. The talcum powder by the way is responsible for the ”smoke“ seen after an airbag is activated Gas generator: airbags use tablets made of sodium azide as propellant. After the ignition, they react to finally form nitrogen gas filling the airbag. Vent holes ensure a controlled deflation

THE MID-60S ALREADY SAW THE START OF AIRBAG TESTS juries and in a few cases even fatalities. For this reason the initially very urgent call for passenger cars to be equipped with airbags as standard in North America was postponed further and further. Meanwhile Mercedes-Benz in Stuttgart was working on an airbag technology that was different in many respects: the safety specialists at Mercedes-Benz put their faith in propellant charges

Initiator: a current pulse sent by the control unit activates the electric match which in turn ignites the propellant. The initially hot gas (approx. 1,350° C) is cooled by the expansion to about 150° C

Signal from the control unit: airbags are activated by a central Airbag control unit (ACU). the unit gets its information by various sensors in the vehicle. The most important criteria measured is deceleration

RESTRAINT SYSTEMS AIRBAGS

The driver airbag (volume approx. 64 litres) is equipped with a two-stage gas generator. Two performance stages can be activated depending on the detected vehicle deceleration rates, with a time delay between ignition of the first and second stages. to generate the gas, not gas stored under pressure. Neither was the airbag developed as a stand-alone restraint system, but always as a component working together with the seat belt. This is expressed by the abbreviation SRS (Supplemental Restraint System) used internationally for airbags. By 1970 MercedesBenz was able to report the following about its crash test findings in a letter to a

As a special feature, the front passenger airbag (volume approx. 112 litres) has a pyrotechnically activated adaptation stage in addition to the two-stage gas generator. The damping effect on the occupant during immersion into the airbag is stronger or weaker as required, depending on seating position and level of inflation.

The windowbag (volume approx. 40 litres) is inflated by a gas generator located in the roof area behind the B-pillar in the event of a crash. The windowbag case is more robust thanks to the use of a new weaving technique (X-Tether technology): this makes for more taut inflation over a longer period.

The beltbag is an inflatable seat-belt strap that is able to reduce the risk of injury to passengers in the rear in a head-on collision by lessening the strain placed on the ribcage (for details see page 79).

INTERACTION BETWEEN SEAT BELT AND AIRBAG German motoring magazine: “The effectiveness of the airbag system in conjunction with a lap belt and head-rest in both frontal and rear-end crashes can be described as good.” From 1967, practical experiments began using chemicals to generate the gas, similar to the solid fuels used to power rockets. In contrast to gas-filled cartridges, this form of propellant charge proved a reliable and fast gas generator. The resulting gas mixture consists mainly of nitrogen, and in fractions of a second inflates the airbag made from a specially woven fabric to form a soft cushion that catches passengers as they

THE AIRBAGS in the new S-Class

In the USA the kneebag for the driver is standard equipment. In a frontal collision it is able to reduce loads on the driver’s lower extremities, and is favourable for the overall body kinematics.

The thorax-pelvis sidebags for the driver and front passenger have a volume of 17 litres and are integrated into the front seat backrests.

If the S-Class is equipped with the Executive seat (reclining seat), the seat includes the innovative cushionbag as standard. The airbag is located under the seat cushion upholstery of the Executive seat, but on top of the plastic seat shell. In the seat’s reclining position it prevents the occupant from sliding under the belt in the event of an accident (so-called submarining). This is because it raises the front section of the seat cushion upholstery.

The sidebags in the rear with a volume of 12 litres are integrated into the bodyshell in the area of the rear interior side panels.

RESTRAINT SYSTEMS AIRBAGS

SLOWED DOWN Braking Bag

are flung forward by an impact. The key findings from the early tests were incorporated into patent no. DE 2152902 C 2, which the then Daimler-Benz AG filed on 23 October 1971. This patent application is a key document covering the entire airbag development process at Mercedes-Benz. This is because it already describes the operating principle of the new technology as it was to be realised in series production ten years later: Sensors register the particularly heavy deceleration that typically occurs

during impacts, and trigger the airbag mechanism. This fires a propellant charge (at the time using sodium azide, potassium nitrate and sand), which mainly turns into

MORE AND MORE AIRBAGS COMING INTO USE gaseous nitrogen plus a little water and oxygen when it explodes. As the series of tests soon showed, the airbag only really reaches its full performance potential in combination with the seat belt.

The Experimental Safety Vehicle ESF 2009 (see page 36 f.) demonstrates one spectacular example of how airbags might be used in the future: the “Braking Bag” concealed in the vehicle floor can become an auxiliary brake. If the sensors and control unit predict that an impact is certain, the “Braking Bag” is deployed just before the collision and supports the vehicle against the road surface with its friction coating. The brake dive of the vehicle increases the friction and has an additional braking effect up to the impact.

In 1992 the driver air bag, and in 1994 the front passenger airbag, became standard equipment in every Mercedes-Benz passenger car. Because the airbag modules were becoming increasingly smaller thanks to constant improvements by the engineers, they could also be placed in other locations in the vehicle to provide comprehensive protection even in lateral collisions: in 1993 Mercedes-Benz presented the sidebag as a design study, and in 1995 the sidebag was launched as an optional extra initially for the E-Class. From 1998 the

To make sure that airbags only deploy in an accident, and on no account by mistake, Mercedes-Benz intensively test them with so-called misuse tests. Here is an SLS AMG in a simulation of mounting a kerb

THE WINDOWBAG as a protective curtain In 1998 Mercedes-Benz was the first automobile manufacturer to introduce the windowbag. Both the front and rear occupants benefit from this large-area head protection, as this study by Mercedes-Benz accident research shows. An analysis of real accidents shows that the windowbag considerably reduces the severity of injuries: the proportion of severe injuries and fatalities in side collisions is reduced from 55 % to 25 %.

Comparison of injury severity at a side collision, belted passengers on impact side with and without window-bag Percent 100 Fatalities

Lightly Injured 60

Not Injured

40 20 0

Severely Injured

No windowbag

Windowbag activated

Source: DBCars, Dec. 2007

RESTRAINT SYSTEMS AIRBAGS

windowbag became standard equipment initially in the S-Class. In 2001 the head-thorax sidebag was introduced for the roadsters in the Mercedes-Benz SL-Class. Adaptive front airbags had their debut in the W 220-series S-Class (1998). In the new S-Class generation (2013) this restraint system configured according to accident severity is a major further development: the driver airbag is equipped with a two-stage gas generator. Two performance stages can be activated depending on the detected vehicle deceleration rates, with a time delay between ignition of

ADAPTIVE AIRBAGS RESPOND TO THE IMPACT SEVERITY the first and second stages. As a special feature in addition to the two-stage gas generator, the front passenger airbag has a pyrotechnically activated adaptation stage. The damping effect when the occupant is immersed in the airbag is stronger or weaker as required, depending on seating position and level of inflation. ■

YOUNG RESEARCHERS Traffic safety education Over 30 years have passed since the world premiere of the airbag at Mercedes-Benz. Meanwhile the number of airbags installed in vehicles has constantly increased, and the advances in sensor systems, gas generators and airbag covers have been immense. Yet nothing about the principle of the “Impact protection device for the occupants of a motor vehicle” (to quote the Daimler patent of 1971) itself has changed to this day. Head of crash testing Ferdinand Gaiser, who enjoys passing his passion for technology and his safety awareness on to children and adolescents, has developed a special “egg-protection system” that helps them to understand the principle of the airbag. At interactive technical shows or as part of school holiday programmes, he uses analogies in the structure of an egg and the human body to explain to young people how airbags and crash tests work. At the same time Gaiser is making a contribution to traffic safety education.

Principle: using analogies in the structure of an egg and the human body, Ferdinand Gaiser helps children to understand the workings of the airbag and crash tests

RESTRAINT SYSTEMS SEAT BELT

NUMBER ONE LIFESAVER

A BOND FOR LIFE TO THIS DAY THE SEAT BELT REMAINS ONE OF THE MOST IMPORTANT IN-CAR SAFETY SYSTEMS, AS IT REDUCES THE LOADS ACTING ON THE WEARER DURING AN ACCIDENT. BELT TENSIONERS AND BELT FORCE LIMITERS HAVE PERFECTED THIS PROTECTION.

ost people now use their seat belt: at present around 98 percent of all car occupants in Germany wear their

seat belt, as a survey by the Federal Office for Roads and Traffic (BASt) for 2012 shows. There are only minor differences between rates of use for drivers, front passengers and other pas-

sengers, or for different road categories, and these have remained almost constant compared to the previous year. An encouraging development, as passengers not

wearing a seat belt run a high risk of injury even at moderate inner-city road speeds: even during a frontal impact at 30 km/h, the acceleration forces acting on the occupants are so high

Self-testing by brave Daimler engineers: whether on the seat belt sledge …

… or in the vehicle, the belt is tested personally if there is no dummy available

A layer of foam material simulates a winter jacket in the belt tensioner test

Seat belt straps are manufactured from up to 300 interwoven threads. Each thread consists of over 100 extremely fine polyester filaments

RESTRAINT SYSTEMS SEAT BELT

INFLATED Beltbag in the rear Should the crash sensors detect a severe frontal impact, the airbag control unit triggers deployment and inflation of the beltbag. A gas generator then inflates the multi-layered belt strap with Velcro seams to nearly three times its normal width. By better distributing the forces acting on the rear seat occupant, the beltbag reduces the risk of injury in a frontal collision.

RAISED Belt buckle extender An electric motor automatically raises and retracts the belt buckle. This reduces any belt slack in the area of the pelvis and thorax, so that passengers are secured more firmly. Fastening the seat belt is also made easier. If PRE-SAFE ® is activated in critical driving situations, there is also reversible belt tensioning in the rear via the active belt buckle.

that they are unable to absorb the impact with their arms. And an occupant without a fastened seat belt who suffers a collision with a fixed object at 50 km/h is subject to a force that corresponds to jumping from a fourth-floor window and falling twelve metres. Rear seat passengers not wearing a seat belt can become projectiles in an accident, as they are flung forward at 30 to 50 times their weight. This means that a 70 kg adult on a rear seat who is not strapped in builds up a load of around three tonnes during an impact at

SERVED Belt feeders in the front

50 km/h – the weight of a young elephant. Seat belts fulfill two major functions: They prevent the occupants from being thrown from the car in an accident. They also help to

LIFE-SAVER FOR ONE MILLION PEOPLE protect passengers from excessive rates of acceleration, and can prevent body areas from impacting vehicle components. In 1985 the German Patent Office nominated the seat belt as one

of eight inventions that have brought most benefit to mankind in the last 100 years. Estimates suggest that seat belts have saved the lives of over one million people worldwide. Seat belt straps are manufactured from up to 300 interwoven threads. Each thread consists of over 100 extremely fine polyester filaments. These filaments have a thickness of 250 to 400 micrometres, and are therefore about twice as thick as a human hair. Around 30,000 metres of filament are used per metre of belt strap - resulting in an overall length

An active belt feeder (e.g. in the E-Class Coupé and Cabriolet) makes it easier to fasten the seat belt. As soon as the ignition key is turned to position 1 and the seat belt is not inserted in its buckle, an electric motor extends plastic sections out of the rear side panels and bring the belt into a convenient position. When the seat belt has been fastened, the feeder retracts again. The automatic belt feeders for the driver and front passenger can also be operated by a button in the centre console.

RESTRAINT SYSTEMS SEAT BELT

TO MAKE SURE THE BELT LETS GO WHEN IT SHOULD

of around 450 kilometres per vehicle. A thermofixing process after weaving ensures that the belt has certain predefined properties, such as maximum elongation. During thermofixing

SEVERAL HUNDRED ULTRA-THIN THREADS OF POLYESTER the belt straps are heated to over 200 degrees Celsius, then cooled down. The duration and tension are precisely specified. The seat belt, which remains the main occupant protection component in modern cars, is already over 110 years old: Gustave Désiré Lebeau was the first to register a patent for it in Paris on 11.05.1903. The Frenchman used crossed-over leather straps to secure the occupants of automobiles. Safety pioneer Mercedes-Benz first presented this new Passive Safety feature in 1957 - “Restraining belt as used in aviation” was the description given to the lap belt for the open-top Mercedes-Benz 300 SL (W 198 II) optionally available from 1958. In that same year Mercedes-Benz offered comparable seat belts for all passenger car models with individual front seats. Following the introduction of the seat belt as an optional extra, Mercedes-Benz continuously developed this restraint system further. The first versions were still lap

belts attached to the vehicle’s bodyshell, and they had to be individually adjusted to fit each passenger. While this was awkward, it provided better protection in an accident than having no belt at all. The customers who became convinced about the new system included the West German Chancellor, Konrad Adenauer. He had a lap belt installed in the rear of his Mercedes-Benz 300. By the end of the 1960s the three-point seat belt had prevailed as the final form for passenger cars, combining a lap belt with a shoulder belt. When a retraction reel was added, it became the inertia-reel seat belt. In 1973 Mercedes-Benz included this form of seat belt as standard equipment for all front seats. In 1979 the installation of three-point inertia-reel seat belts for the rear seats also became standard.

INERTIA-REEL BELT STANDARD SINCE 1973 AT MERCEDES-BENZ Even in the 1970s, the accident researchers at Mercedes-Benz were aware that during a severe frontal impact, the seat belt cannot always prevent the head and body from impacting the steering wheel and dashboard. The reasons for the limited protective effect were looseness (“belt slack”), stretching and the time delay of the inertia-reel device (“film-roll effect”).

In 1981 (standard from 1984), Mercedes-Benz engineers prevented the inherent free travel of the belt with the belt tensioner, which rolls up and tightens the belt within milliseconds in a crash. In 1995 MercedesBenz presented the integrated belt force limiter. This limits the force exerted on the occupant by the belt during severe impacts (for details of belt tensioner and

INTEGRAL SAFETY CONCEPT WITH AIRBAG AND PRE-SAFE® belt force limiter see opposite page). Unlike in the case of many other manufacturers, the belts in the rear of a Mercede s-Benz likewise feature belt tensioners and belt force limiters. The protective action of the seat belt was finally perfected with the airbag (from 1981), and the innovative, preventive safety system PRE-SAFE ® (2002): When the PRE-SAFE ® sensors recognise the danger of an accident, the system uses electric motors to pre-tension the belt tensioners and build up the maximum protective effect of the seat belt (see page 44/45). In 2013 Mercedes-Benz enhanced the safety system for passengers in the rear even further with the belt buckle extender and the beltbag in the new S-Class. ■

This inertia reel combines a belt tensioner with a belt force limiter. At Mercedes-Benz this version is used in the rear, and in some cases the inertia-reels in the front additionally have reversible PRE-SAFE® functions.Operating principle: There are steel balls inside the bent tube. When the belt tensioner is triggered, a pyrotechnical charge is activated. The steel balls transfer their kinetic energy to a gear wheel mounted on the shaft of the seat belt retractor. Accordingly the belt is retracted by up to 15 centimetres and is taut against the occupant’s body. To avoid dangerous peak loads, the belt force limiter comes into operation. Once a certain force has been reached, the shaft inside the belt retractor is twisted on the torsion principle. This causes a controlled release of the belt strap.

Belt strap

Pyrotechnical charge

Steel balls

Shaft

Seat belt retractor

RESTRAINT SYSTEMS FACTS, FIGURES AND CURIOSITIES

DID YOU KNOW? 15

BIRDS

1976 Men feared for their freedom, women for their busts: Although it became mandatory to wear a seat belt in West Germany on 1 January 1976, the seat belt was the subject of passionate debate in the mid/late 1970s. Horror stories did the rounds about cars on fire or submerged under water, from which occupants wearing seat belts were unable to escape. In December 1975 the news magazine “Spiegel” even devoted its cover story with the title “Strapped to the car” to these various fears. Only the fine imposed for non-use in 1984 convinced the skeptics and greatly increased the rate of use.

SECTION Photo: enens - Fotolia.com

An animal experiment like this would be unthinkable nowadays, but in the early phase of airbag development the Mercedes-Benz researchers had recourse to unusual methods: to find out what effects the gas emissions have after activation of the airbag, the technicians deposited a cage containing 15 canaries in a test vehicle. The airbag was then triggered. The birds survived the experience completely unruffled. Incidentally, the engineers tested the effect of the bang on themselves, under the supervision of an ENT specialist.

In Germany the trade supervisory authorities prescribe that every car workshop handling airbags and belt tensioners must nominate a trained specialist who is responsible. According to Section 34, clause 2 of the explosives law, this person must be in possession of a certificate of competence. This requires attendance at a usually 1-day seminar where specialist knowledge on pyrotechnical systems is imparted.

AUTO

BILLION EURO

When rear-end collisions occur, whiplash injuries can be caused by rapid, alternating fore-and-aft movements of the head and overstressing of the cervical vertebrae. According to estimates by the EU Commission, this leads to annual costs amounting to around eight billion euros. Mercedes-Benz reduces this injury risk with appropriately designed head restraints. The basic requirement for this is best possible adjustment of the distance from the back of the occupant’s head. This is quite simple in the case of the A-Class, for example: the head restraint can simply be pulled forward until it engages. There are different engagement positions. If the head restraint is to be adjusted to the rear, the release button must be kept depressed while the restraint is pushed rearwards. When the head restraint has reached the desired adjustment, the button can be released and the restraint snaps into position.

2000 In 1981 the Mercedes-Benz “Auto 2000” research vehicle defined the status of safety technology. Its innovations included integral seats for the driver and front passenger, where all the belt attachments were mounted directly on the seat, and an integrated child restraint system.

ASSISTANTS

STABLE DYNAMICS POLAR BEARS can reach a weight of up to 800 kg and move at over 40 km/h. But they keep a grip on things even where the going is slippery: the soles of their feet have a dense covering of hair, making it harder to slip over on the ice. All four paws are armed with five non-retractable claws.

THE BASIS FOR MANY

ASSISTANCE SYSTEMS

ARE THE HANDLING SAFETY SYSTEMS ABS AND ESP®. NUMER-

BAS, LANE KEEPING AND BLIND SPOT ASSIST NOWADAYS

MAKE DRIVING SAFER AND MORE COMFORTABLE. THESE ALSO INCLUDE

COLLISION PREVENTION

ASSIST AND THE RECOGNITION OF TRAFFIC SIGNS. 84

Photo: Winfried Schäfer/imagebroker/Corbis

OUS OTHER HELPERS SUCH AS

ASSISTANTS ABS/ESP

CONTROLLED VEHICLE DYNAMICS

THE CAR ASSISTS THE DRIVER OUTSTANDING DRIVING SKILLS WERE REQUIRED TO KEEP THE VEHICLE ON COURSE IN EXTREME CONDITIONS. UNTIL MERCEDES-BENZ INTRODUCED FIRST ABS AND THEN ESP速. NOWADAYS BOTH ARE LEGAL REQUIREMENTS, AND DRIVING IS SAFER IN MANY RESPECTS.

Extreme trials in Namibia: with six driving modes, the suspension of the M-Class is ready for any situation. One example is Offroad ABS. It optimises the braking characteristics, especially on loose substrates

ASSISTANTS ABS/ESP

t all started with wheels that locked when braking. The problem was this: the vehicle cannot be steered if the wheels are locked, as they transfer lateral forces to the road less effectively than rotating wheels. As early as the second half of the 1950s, Daimler examined the use of anti-lock braking systems familiar from aviation in its vehicles, however these proved unsatisfactory. In 1963 the company began to develop in-house components for an electronic/ hydraulic control system capable of higher performance. In 1966 the Teldix company, which was later

taken over by Bosch, became a development partner. By the end of 1970 the goal seemed to have been substantially reached: Daimler issued invitations to a “press demonstration” on 9 December, and the Executive Board member for development, Hans Scherenberg, explained the current status.

DRIVING STRAIGHT AHEAD ON A BEND IS VERY DANGEROUS “During panic braking, strong drivers in particular apply a higher level of brake pressure, which causes one or more wheels to lock. If the vehicle is virtually unladen or the road surface is slipHard going: rapidly changing road surfaces with varying levels of grip are an extreme challenge for the control quality of ABS

Premiere: from 1978 the S-Class was kept on course by ABS

In the past: without ABS the driver had a tough job

Safe avoiding action: vans were also included in ABS development work at an early stage

ANTI-LOCK BRAKING SYSTEM Braking without skidding When tyres start smoking, cars start skidding: what can still be seen in Formula 1 today was the norm for every regular production car 35 years ago. Hard braking brings the wheels to an abrupt stop, the braking distance increases and the vehicle can no longer be steered. This only changed in 1978: The 116-series S-Class was the first automobile worldwide that could be ordered with fully electronic ABS. Since 2004 all new cars in Europe have been equipped with this technology. When the wheels lock up: ABS was also tested with the /8 as the precursor to the E-Class. This bestseller never enjoyed the benefit of ABS, however

ASSISTANTS ABS/ESP

pery, however, very little pedal pressure is needed before locking occurs, and steerability and handling stability are lost. Metering the pedal pressure during emergency braking there-

ABS DEVELOPMENT TO PRODUCTION MATURITY TOOK 15 YEARS fore requires awareness, experience and self-control on the part of the driver, however this is often lacking. Acting purely on instinct, many drivers apply the brakes with full force in such situations, rather than metering the braking action

in accordance with the circumstances.” Scherenberg described the consequences: “If the front wheels lock while the rear wheels are turning normally, the vehicle travels straight ahead whatever the current steering angle… On a straight road this behaviour is relatively favourable…, but as we know, driving straight ahead on a bend is very dangerous. If the rear wheels lock, however, …the vehicle can easily break away at the rear axle because locked wheels lose their lateral stability.” In his presentation, Scherenberg mentioned a period of two years before the intro-

Full range of choices: the AMG DRIVE UNIT in the SLS AMG enables the suspension control systems to be set up according to the driver’s wishes and for the intended purpose, right up to Race Control set-up for the racetrack

duction of the Anti-Block System (A-B-S). In fact ABS, developed together with Bosch and now in its 2nd generation, only reached production maturity eight years later. It had its world premiere in the S-Class in 1978. In 1974 the changeover from analogue to digital electronics began. It was only the invention of integrated circuits that made it possible to build small, robust computers that were capable of converting the data from the wheel sensors into e.g. acceleration data in minimum time, and of consistently and reliably actuating the valves controlling the brake pressure. Moreover, no more me-

TORQUE VECTORING BRAKE Specific braking action for dynamic cornering

BASIC FUNCTION ESP ® In case of understeer

In case of oversteer With ESP ESP® assists the steering reaction of the driver by applying the brakes at the rear inside wheel ®

Without ESP ® The car does not turn enough and leaves the road

More safety at the cornering limits: if the ESP® sensors register a tendency to understeer, the stability programme initiates specific braking intervention at the inside rear

wheel. This causes a slight yawing motion around the vehicle’s vertical axis. The effect: the vehicle steers into the bend precisely and with no loss of power

Vehicle’s center of gravity

Intended course

without ESP ®

Without ESP ® The car turns more sharply than intended and possibly spins. The driver needs to countersteer.

with ESP ®

With ESP ® ESP® assists the driver by applying the brakes at the outside front wheel

ESP ® brake application

Torque about the vehicle’s vertical axis, created by brake application 91

ASSISTANTS ABS/ESP

chanical rotating mass sensors were used, as the wheel acceleration and rpm were now calculated purely electronically from the rpm sensor signals. During the development work it soon became clear that not only the wheel acceleration but also the wheel slip must be taken into the equation: to this day, this combination is the basis for all dynamic control systems.

ONLY DIGITAL ELECTRONICS MADE ABS POSSIBLE AT ALL A control unit processes the sensor signals, the hydraulic unit instantly and precisely regulates the brake pressure at each wheel. In 1984 all Mercedes-Benz passenger cars were given ABS as standard, and ten years after its introduction no less than one million Mercedes-Benz cars with ABS were on the roads worldwide. As a voluntary obligation by the European automobile industry, all passenger cars have been equipped with ABS as standard since 1 July 2004. Mercedes-Benz also took on the pioneering role in the commercial vehicle sector. ABS for compressed air brakes, a joint development with WABCO, already became available in 1981. Since 1986 the brand’s large touring coaches have been equipped with ABS as standard, and since 1991 also its truck models. The next step was acceleration skid control (ASR),

1969 test: it soon became clear that both wheel acceleration and slip must be registered by sensors

Bus at the physical limits: today ESP® also ensures greater safety in the Citaro

WHEN AN ELK BLOCKS THE ROAD All’s well that ends well

ESP® enters series production: In 1995 Mercedes-Benz demonstrated on snow…

which became available in the S-Class (W 126) models with V8 engines from 1985. When the wheel sensors detect that drive wheels are spinning, the engine torque is reduced and/or the spinning wheel is slowed down by the wheel brake (ETS). This was followed by the automatic locking differential (ASD) and automatically activated 4MATIC all-wheel drive, both of which ap-

peared in the great innovation year of 1985. Additional sensors that recognise the driver’s direc-

NEW SENSORS RECOGNISE THAT THE CAR IS SKIDDING tional intentions (steering angle sensor) and whether the car is sliding sideways (lateral acceleration sensor),

…how much easier the S 600 Coupé could be controlled with ESP®

or is in the process of rotating around its own vertical axis (yaw rate sensor), provided the basis for the electronic stability programme ESP® (see diagram on page 91 for operating principle). An engineer’s dream and a further, major step towards reducing accident figures had become reality: for the first time, the technology effectively supported drivers in situations where they

After ABS and acceleration skid control ASR, Mercedes-Benz went a stage further in 1995 and introduced ESP® in the luxury S 600 Coupé. From then on, the electronic stability programme held a protective hand over drivers at the physical limits. These were exceeded by a Swedish car tester, who caused the new compact A-Class to capsize during an abrupt evasive manoeuvre (“Elk test”). What at first seemed a humiliation for MercedesBenz became a triumph: in 1997 the company systematically made ESP® standard equipment – first for the A-Class, then for all its models. All the other manufacturers had to follow suit: following a directive by the European parliament and the Council dated 13 July 2009, it has been mandatory to equip all passenger cars newly registered in the EU with ESP® as standard since November 2011.

Trendsetter rather than laughing-stock: the A-Class was given ESP® as standard from 1998

ASSISTANTS ABS/ESP

were on the verge of losing control. In 1995 ESP® was first introduced as standard in the S-Class. “If all cars were equipped with the stability programme, more than 20,000 of these serious accidents with over 27,000 accident victims could be prevented in Germany,” said Prof Dr Thomas Weber, the Daimler Board of Management member for research and technology, and head of development for Mercedes Car Group. “Alongside the seat belt, airbag and ABS, ESP® is easily the most important

Staying safe throughout winter: control of the Mercedes-Benz all-wheel drive system 4MATIC is also based on the ESP® sensors. The 4x4 family from Mercedes-Benz currently comprises over 60 models.

safety system in modern passenger cars.” His wish was to come true: ESP® has been mandatory for new cars in Europe since November 2011. In 1996 Brake Assist (BAS) followed as a standard feature for all MercedesBenz passenger cars. During emergency braking, this ensures that the most effective brake pressure is built up immediately, irrespective of the driver’s pressure on the brake pedal. You will read more about Brake Assist PLUS (BAS PLUS) in the next chapter. ■

Free choice: with six driving modes, the ON&OFFROAD package in the ML and GL optimises vehicle dynamics and safety

ACTIVE CURVE SYSTEM The M-Class serenely copes with any terrain ACTIVE CURVE SYSTEM Less roll

Driving straight ahead: Comfort is improved, as the rotary actuators decouple the two halves of the front and rear anti-roll bars in this situation, meaning that the anti-roll bars are “open” and do not react to a stimulus on just one side, such as bumps or potholes.

Cornering: Improved ride comfort and vehicle dynamics, as the torsional moments and angles of the stabilisers are actively influenced. Moreover, the torsional moment of the stabilisers also remains constant with one-sided stimuli, for example when crossing a pothole on the outside of the bend. The different control at the front and rear axles variably distributes the body roll.

Off-road: On extreme terrain at low speeds, the actuators decouple the two transverse stabilisers at the front and rear axles. This allows a higher degree of axle articulation, and therefore ground adhesion.

The active roll stabilisation ACTIVE CURVE SYSTEM can be combined with both the AIRMATIC air suspension system with adaptive damping system (ADS) and with the ON&OFFROAD package. The system operates on the front and rear axle with active anti-roll bars, and controls these automatically depending on the lateral acceleration, the road speed and the position of the ADS Comfort/Sport switch. Compensating the body roll angle when cornering increases both agility and driving pleasure.

ASSISTANTS BAS PLUS

NEW ASSISTANCE SYSTEMS

RECOGNISING DANGER, SUPPORTING THE DRIVER PREVENTING ACCIDENTS AND MINIMISING THEIR CONSEQUENCES: MERCEDES-BENZ SYSTEMATICALLY PURSUES THIS STRATEGY WITH NUMEROUS NEW ASSISTANCE SYSTEMS. COMFORT AND SAFETY ARE ENHANCED AT THE SAME TIME. THE PRINCIPLE HERE IS: AS MATURE AS THE SYSTEMS ARE – THE DRIVER ALWAYS RETAINS CONTROL, ALSO FOR LEGAL REASONS. THE DRIVER SHOULD BE SUPPORTED, NOT SIDELINED.

ercedes-Benz drivers first received assistance with emergency braking in 1996, from Brake Assist BAS: Full braking performance is available as soon as the brake pedal is operated. Over several development stages, BAS became Brake Assist PLUS (BAS PLUS). This automatically calculates the brake pressure necessary to prevent a crash. However, no more brake pressure than necessary is applied, so

that traffic following behind also has space for braking. By the interaction of all its components, this adaptive pre-control of the braking system based on anticipatory sensors is a further innovation optimising vehicle deceleration in hazardous situations. BAS PLUS also goes into action if PRE-SAFE® Brake is on board. A visual and acoustic warning is given if the danger of a collision is recognised. If the driver reacts and operates the brake pedal, BAS PLUS takes

over and provides the optimum brake pressure. If the driver fails to respond to the visual and acoustic warning, PRE-SAFE® Brake first initiates partial braking. If a collision is recognised as unavoidable, there is emergency braking to mitigate the consequences. The current development stage of Brake Assist BAS PLUS from Mercedes-Benz, which has initially been presented in the S- and E-Class, and is available in the new C-Class, is now not only able to support the driver in con-

Emergency: automatic emergency braking and activation of the PRE-SAFE® systems can mitigate the consequences of accidents

RECOGNITION OF CROSSING TRAFFIC Help in dire emergencies The latest generation of sensors (long and short-range radar, stereo multifunction camera) is also able to recognise crossing traffic and oncoming traffic. Objects recognised include e.g. trucks, cars, motorcycles and bicycles. If critical situations involving crossing traffic are detected, BAS PLUS makes the necessary brake pressure available as soon as the driver brakes. In addition, PRE-SAFE® functions such as the belt tensioners are activated. Accident black-spot: accidents at junctions will often be avoidable in future, thanks to recognition of crossing traffic

ASSISTANTS BAS PLUS

voy traffic by preventing or mitigating the consequences of rear-end collisions. Thanks to the new Cross-Traffic Assist function, critical situations involving crossing traffic can also be defused. City centre junctions are major accident blackspots. The collisions here can mostly be put down to driver distraction or misjudgement. Whereas humans often react too slowly, assistance systems are immune to that brief moment of shock. If this anticipatory system detects a hazardous situation of this type, it prompts the driver to start emergency braking by activating

visual and acoustic warnings. If the driver presses the brake pedal too tentatively, BAS PLUS will step in by automatically boosting brake pressure for effective emergency braking, even applying the brakes at full

CROSS-TRAFFIC ASSIST IS A NEW FEATURE power if necessary. Applying just the right amount of braking power for the situation at hand maximises the available braking distance for traffic behind. The CrossTraffic Assist function is operative at speeds up to I also brake for cars: the 3rd generation of ABA 3, the emergency braking assistant for trucks, is able to recognise stationary obstacles and brake autonomously

BAS PLUS AND PRE-SAFE® BRAKE Electronic crumple zone

Visual and acoustic warning

BAS PLUS: boosts inadequate braking by the driver as appropriate to the given situation

Brake Assist PLUS (BAS PLUS) calculates the brake pressure necessary to prevent a rear-end collision. Additional protection is provided by the innovative PRE-SAFE® Brake from Mercedes-Benz: when an imminent rear-end collision is detected, it prompts the driver to act by means of visual and acoustic signals. If the driver fails to act, autonomous partial braking gives a further warning and the vehicle speed is reduced. If there is still no driver response, the system is able to initiate emergency braking before the now unavoida-

PRE-SAFE ® Brake: autonomous braking when the driver fails to respond

Detection of pedestrians in the area in front of the vehicle

ble impact, thereby greatly lessening its severity. The latest generation is not only able to recognise vehicles ahead, but also pedestrians. The system makes use of information from the radar system and stereo camera. PRE-SAFE® Brake with pedestrian detection and city braking function is active at speeds up to 72 km/h and is able to prevent accidents with pedestrians as well as with stationary vehicles up to a speed of more than 50 km/h.

approx. 72 km/h. BAS PLUS is able to aid the driver in linear situations at any speed. Brake Assist BAS PLUS with Cross-Traffic Assist is potentially able to either prevent or lessen the severity of around 27 percent of all

ASSISTANTS ALSO FOR TRUCKS AND BUSES accidents at road junctions resulting in injury. In Germany this corresponds to around 20,000 accidents per year. As an automobile manufacturer who has always also

played a decisive role in the commercial vehicle sector, Mercedes-Benz makes innovations available across all vehicle classes: Anti-lock braking system, acceleration skid control, disc brakes allround, electronically controlled braking system, high-pressure braking system, Brake Assist, Lane Assistant, roll control, distance control – the list of safety technologies that celebrated their world premiere in trucks and buses from Mercedes-Benz is a long one. One of the development highlights is the revolutionary Active Brake Assist (ABA). Introduced in 2006 in the Mercedes-Benz Actros

heavy truck, it has since proved highly successful in practice. In 2012 the new Mercedes-Benz Actros, and also its distribution-oriented

ABA 3 MEETS THE REGULATIONS FOR 2018 brother, the Antos, became even safer. The third generation of the unrivalled Active Brake Assist 3 now also initiates autonomous emergency braking when stationary obstacles are recognised. This means that the Actros is not only able to mitigate the effects of rear-end colli-

sions as before, but is also able to prevent them – a further milestone in safety developments for trucks. It also means that already today, these Mercedes-Benz trucks meet the legal requirements of the regulation “AEBS Advanced Emergency Braking System” only coming into force from 2018. The radar technology used for Active Brake Assist 3 operates reliably in all weather and light conditions, and is active throughout a trucks speed range, from fast walking speed up to motorway speeds using the speed limiter at 89 km/h. ■

ASSISTANTS LANE KEEPING AND BLIND SPOT Road marking

LANE KEEPING AND BLIND SPOT ASSIST

ON THE RIGHT TRACK STRAYING INTO ONCOMING TRAFFIC OR OFF THE ROAD,

Course correction: braking intervention by ESP® prevents the vehicle from leaving its lane unintentionally

CUTTING-IN ON AN OVERTAKING VEHICLE – ACTIVE ASSISTANCE SYSTEMS CAN PREVENT THESE DANGEROUS MANOEUVRES.

et’s admit it: we have all done this at some time. A moment of inattention, fiddling with the radio or mobile phone – and already the car has moved dangerously close

to the edge of the road. With the help of Lane Keeping Assist the driver is warned by steering wheel vibrations when this happens. When the multifunction camera recognises that the vehicle is leaving its lane unintentionally, a small electric

motor makes the steering wheel vibrate. The latest further development is Active Lane Keeping Assist. This is now also able to intervene should the driver inadvertently cross a broken line when the neighbouring lane is not clear,

MPC

Multi-Purpose Camera

Optical Lane Detection

Vibration element for haptic warning of driver Vehicle

Active Lane Keeping Assist: when the camera recognises that the vehicle is straying from its lane, it is brought back on course by ESP® -controlled braking intervention

Lane Keeping Assist: when the camera recognises that the vehicle is straying from its lane, the steering wheel vibrates to warn the driver

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ASSISTANTS LANE KEEPING AND BLIND SPOT

Support for professionals: Blind Spot Assist is even more important where there is no rear window, which is why the new Sprinter has it

BLIND SPOT ASSIST Safe lane-changes Blind Spot Assist developed by Mercedes-Benz uses radar technology to monitor the areas immediately next to and behind the vehicle. If the system registers another vehicle in the exterior mirror’s blind spot, this is shown by a red warning triangle lighting up in the relevant mirror. If the indicators are operated despite the visual warning, an acoustic warning is sounded as well. Active Blind Spot Assist not only warns of danger, but can help to prevent accidents by means of targeted braking intervention.

Warning triangle: information before the other road user appears in the mirror

meaning that a lane-change could result in the risk of a collision. The system can determine if this is the case using the information from the stereo camera and the radar system. The latter has been supplemented by a sensor at the rear, which works in unison with the other sensors in the front and rear bumpers. Active Lane Keeping Assist is not only capable of

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recognising critical situations such as overtaking vehicles, vehicles to be overtaken and parallel traffic, it

lane is not clear, not only does it cause the steering wheel to vibrate in pulses as a tactile warning for the

WARNING STAGE ONE: RED TRIANGLE IN THE EXTERIOR MIRROR can also respond effectively to oncoming traffic. If the system detects that the vehicle is crossing the lane markings when the adjacent

driver, it guides the vehicle back into lane by applying a corrective braking force on one side via ESP®, now also when the vehicle crosses

broken lines. It thereby complements Active Blind Spot Assist, and for the first time also enables collisions with oncoming traffic, which can often have far-reaching consequences, to be avoided. Active Lane Keeping Assist is active at speeds between 60 and 200 km/h. If driver activity in the form of active steering, braking or acceleration is detected, for

All-round vision: Blind Spot Assist not only monitors the overtaking lane, but all adjacent lanes

example, or when the indicators are switched on, both the warning and the corrective brake actuation are suppressed. Using the instrument cluster the system can be set for two levels – Standard or Adaptive. Blind Spot Assist keeps an eye on traffic behind: this radar-based system warns the driver before a lane-change if it detects an-

other vehicle in the blind spot of the exterior mirrors. A red triangle appears in the relevant exterior mirror. If

Active Blind Spot Assist can do even more: It intervenes if the driver ignores the warnings and the vehicle

WARNING STAGE THREE: COURSE CORRECTION BY ESP® the indicators are operated despite the warning, the red triangle in the instrument cluster flashes and a warning is sounded.

in the adjacent lane gets dangerously close. Braking intervention at the wheels on the opposite side of the vehicle generates a yawing

motion that counteracts the collision course. The driver is able to cancel the coursecorrecting braking intervention by countersteering with a steering angle larger than five degrees, or by operating the accelerator with a change of more than ten percent. ■

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ASSISTANTS CPA

Greyhound and hare: the developers use the Balloon Car to simulate moving traffic ahead. If the braking distance is inadequate during the tests, the damage is kept within reason

COLLISION PREVENTION ASSIST

COLLISION PREVENTION ASSIST Functioning sequence

PREVENTION OF FRONT IMPACTS

Distance warning – activated if the driver critically approaches a vehicle in front Visual and acoustic warning !

Adaptive Brake Assist – activated if the driver brakes in a critical situation Visual and acoustic warning

COLLISION PREVENTION ASSIST (CPA) IS ON BOARD AS STANDARD, FROM THE

Braking force calculated to the situation is applied and PRE-SAFE® activated

A-CLASS TO THE S-CLASS. THE SYSTEM WARNS THE DRIVER WHEN THERE IS A RISK OF COLLISION. CPA PLUS IS EVEN ABLE TO BRAKE SEMI-AUTONOMOUSLY.

COLLISION PREVENTION ASSIST System details

he radar-based COLLISION PREVENTION ASSIST (CPA) provides the possibly distracted driver with visual and acoustic warnings of identified obstacles and prepares Brake Assist for precision braking. This braking is initiated as soon as the driver firmly

presses the brake pedal. When an impending danger of collision is identified, COLLISION PREVENTION ASSIST calculates the precise braking force ideally needed to avoid an accident and makes the best possible use of any distance remaining. Unlike city braking sys-

tems, CPA not only assists in urban areas but from 7 to 250 km/h. In combination with DISTRONIC PLUS, COLLISION PREVENTION ASSIST PLUS has an additional function. When a danger of collision persists and the driver fails to respond, the system is able to carry out autonomous braking at speeds

of up to 200 km/h, thereby reducing the severity of collisions with slower or stopping vehicles. Depending on the vehicle model, the system also brakes when stationary vehicles are detected up to a speed of 50 km/h, and can prevent front-end collisions up to 30 km/h. ■

COLLISION PREVENTION ASSIST1 Distance warning

• 7 – 250 km/h (moving and stopping objects) • 7 – 72 km/h (still-standing objects)

Collision Warning

• 7 – 250 km/h (moving and stopping objects) • 7 – 72 km/h (standing objects)

Adaptive Brake Assist

• 7 – 250 km/h (moving and stopping, but not still-standing objects)

• 7 – 250 km/h (moving and stopping • 7 – 30 km/h (still-standing objects)

Autonomous partial braking

• 7 – 250 km/h (moving and stopping • 7 – 30 km/h (still-standing objects) • deceleration by brakes up to 6 m/s • avoidance of collisions up to ca. 20 km/h difference in speed

1 2

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COLLISION PREVENTION ASSIST PLUS2

Until 2013 in A- and B-Class: Protection against typical rear end collisions in dangerous traffic situations at speeds above 30 km/h In combination with DISTRONIC PLUS

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ASSISTANTS TRAFFIC SIGN RECOGNITION

Warning of no-entry signs: if Traffic Sign Assist detects a no-entry sign, it shows a clear message in the instrument cluster and sounds a warning

TRAFFIC SIGN ASSIST

ORIENTATION IN THE TRAFFIC SIGN JUNGLE THERE IS AN INCREASINGLY DENSE FOREST OF TRAFFIC SIGNS. TRAFFIC SIGN ASSIST IS DESIGNED TO RELIEVE THE DRIVER’S WORKLOAD. IT CAN DO MORE AND MORE, BUT ITS JOB IS MORE COMPLEX THAN ONE MIGHT THINK BECAUSE TRAFFIC SIGN DESIGNERS HAVE LIVELY IMAGINATIONS.

raffic sign designers are creative people. This certainly makes traffic signs entertaining, but in times of international mobility it also leads to confusion. In 1968, at the Vienna Convention, this caused e.g. the German-speaking countries to agree on a standardisation of the most important traffic signs. At

PICTOGRAMS ARE HARDLY USED IN THE USA the time the old HALT sign was replaced by the international stop symbol. Most European countries and many other nations have meanwhile signed up to this convention. Only in this way is automatic traffic sign recog-

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nition possible. The basis of this standardisation is the use of pictograms that are as easy as possible to understand. This also facilitates recognition and understanding by road users unfamiliar with the local language. Apart from standardised signs, many countries continue to use their own, special signs - for example the famous elk warning signs in Sweden. And major tourist countries such as Spain have not formally acceded to the agreement. Unfamiliar signs can also often be found on eastern European roads. Mainly in the USA, road signs give instructions or information not as pictograms, but in written form - a practically insurmountable hurdle for automatic recognition systems. In clearly control-fixated Germany there are 648 official traffic signs with 1800 variations. As helpful as traffic signs can be in many

cases - less would often be more: this is because the absorption ability of road users is limited, and the forest of signs on the roads is too much for drivers to process. The European record is probably held by Rethelstrasse in

GERMANY: 648 OFFICIAL TRAFFIC SIGNS Düsseldorf, which has 32 signs on a stretch of 50 metres. Even a driver passing them at only 30 km/h has precisely six seconds in which to register all of them. This 0.18 seconds per sign is probably just a tad too short even for those among us who have lightning-fast reactions and the presence of mind of a goalkeeper in the national football team. ■

TRAFFIC SIGN ASSIST Now also identifies no-overtaking and no-entry signs

Camera

Traffic Sign Assist now also identifies no-overtaking zones and can warn of no-entry signs. As before, the camera on the inside of the windscreen registers signposted speed limits, including those on gantries or where there are roadworks. The data are compared with signs stored in the system’s memory, and reconciled with information from the navigation system. The result

can be shown both in the instrument cluster and in the map display. If the camera detects no speed limit signs, the legally prescribed speed limits are shown on the basis of navigation data. No-overtaking signs and their cancellation are also registered, and a visual and acoustic warning is given when no-entry signs are recognised.

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ASSISTANTS PARKING

PARKING ASSIST

AUTOMATIC ENTRY INTO PARKING SPACES CARS ARE TENDING TO GET LARGER, BUT NOT SO PARKING SPACES. YET CAMERAS AND PARKING ASSISTANCE SYSTEMS ARE MAKING PARKING EASIER.

hat, you still park the car yourself? Current MercedesBenz models like the S-Class have their own parking valet on board with them. At speeds below 30 km/h, ultrasonic sensors in the side bumper sections survey the nearside of the road for suita-

ble parallel and end-on parking spaces. If the offside indicators are operated, the system searches on that side of the road. Once a suitable parking space has been found, the parking procedure is as described on the right. With the 360° camera the driver also has a view of the vehicle’s surroundings on the central display. ■

ACTIVE PARKING ASSIST WITH PARKTRONIC Automatic parking and exiting from parallel and end-on parking spaces After activation by the driver, Active Parking Assist recognises parking spaces on the left or right side of the road as required. It allows automatic parking with active steering and brake control in both parallel and end-on spaces. On instruction by the system, the driver needs to select the relevant transmission position

and set the vehicle in motion by accelerating or releasing the brakes. What is more, the system is now also able to manoeuvre out of parallel parking spaces again all by itself with automatic steering and brake control, assuming the vehicle was parked there automatically beforehand.

All-round view: with the 360° camera the surroundings are shown in the display from various perspectives - from the complete panorama with bird’s-eye view to detailed views. Where exits are narrow, crossing traffic in the blind spot is revealed

Development of parking assistance: The tailfins on the saloon models introduced in 1959 still give them their popular name. In fact they were intended as a guide to the driver when reversing the vehicle. In 1991 the large W 140-series S-Class featured extending guide rods; from May 1995 these were replaced by PARKTRONIC with ultrasonic sensors. Even more precision was available from the infrared and radar sensors that measured the distance from 2005, with displays in the dashboard and headlining, the latter visible in the rear-view mirror (photos clockwise)

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ASSISTANTS DRIVING ACADEMY

DRIVER TRAINING FOR EVERY LEVEL

EXPERT AT THE WHEEL The high art of drifting: during the driving events on snow, car drivers practice driving at the limits on frozen lakes. Fun is guaranteed

THE AIM OF THE DRIVING ACADEMY IS TO PERFECT THE INDIVIDUAL STYLE OF DRIVING WHILE HAVING PLENTY OF FUN. THE INTERACTIVE PROGRAMME ROADSENSE FOR YOUNG PEOPLE TRAVELLING AS PASSENGERS IS AN UNUSUAL ONE.

cy patches, emergency braking or sudden evasive action on slippery roads – in critical winter situations it is important to keep a cool head and control the vehicle with confidence. The winter training courses offered by Mercedes-Benz Driving Events or the AMG Driving Academy are specifically aimed at this, and instill intuitive, confident reactions at the wheel. With the reassuring feeling of being in the hands of experienced instructors, the participants practice in the breathtaking winter landscapes of Austria or Sweden, using vehicles provided from the Mercedes-Benz model range to explore their personal limits. In the summer too, numerous training courses are

held regularly on the circuits of traffic safety centres and racetracks – for beginners or professionals, and also for off-road fans. Mercedes-Benz Driving Events Chief Instructor Wolfgang Müller: “Confident and safe vehicle handling is

FUN AND PRECISION ARE THE AIMS OF THE DRIVER TRAINING our goal. And the drivers also experience the additional support they receive from the driver assistance systems. This means that not only are our vehicles safer and safer, but also our drivers thanks to the driver training.” AMG Driving Academy Chief Instructor Reinhold Renger adds: “Apart from the enjoyment of sporty

driving, precision is our aim. This also includes efficiency: maximum engine speeds and smoking tyres by no means guarantee the fastest lap times. These can usually be achieved with considerably less fuel consumption – which has surprised many a participant.” With its unusual RoadSense programme, the Mercedes-Benz Driving Academy closes the wide gap in the traffic education of young people that falls between elementary school and obtaining a driving licence. In this programme, 13 to 15 year-old adolescents are shown new and unfamilar perspectives covering their own behaviour as passengers. Under the guidance of specially trained driving instructors and on enclosed circuits, the adolescents realistically experience typical

Mudbath: special training courses for off-road enthusiasts

Water games: dealing with aquaplaning is also practiced

Instructors: Wolfgang Müller, Chief Instructor for MB Driving Events (in the car), and Reinhold Renger, Chief Instructor at the AMG Driving Academy

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ASSISTANTS DRIVING ACADEMY

conflict situations close at hand in their role as passengers. The aim is to minimise the risks to adolescents in road traffic. The programme takes a unique educational approach, and actively involves each of the students. As passengers the young

13 TO 15 YEAR-OLDS ARE BRIEFLY ALLOWED BEHIND THE WHEEL people experience how much potential conflict can arise in a car for young occupants in particular. They learn how important it is to keep themselves and their feelings under control in road traffic. On the practice circuit they are also briefly allowed behind the wheel under supervision. Thanks to its practical nature, this form of traffic education is not only fun, but also leaves a lasting impression.

Since June 2010, 21,000 young people in Germany alone have taken part at ten Mercedes-Benz locations in eight federal states - more than 780 8th and 9th grade school classes from more than 400 different schools. If Great Britain and the Netherlands are included, where the programme is also available, the number is no less than 30,000 students. With its RoadSense programme the MercedesBenz brand is now a subject of conversation on many school playgrounds, and is impressively managing to put the focus of young people onto safety. ■ Blind faith? The students learn that good passengers intervene if the driver behaves irresponsibly

Class excursion: in Germany alone, more than 21,000 adolescents have already taken part in RoadSense, experienced the conflict situations that passengers typically encounter in road traffic and learned to take a responsible view of them

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Drink and drive? Using “alcohol spectacles”, students experience how spirits may affect reactions; all learnings are journalised

Discussion: before and after the exercises, there is a discussion on how passengers can contribute to traffic safety

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ASSISTANTS FACTS, FIGURES AND CURIOSITIES

33:67

DID YOU KNOW?

2,217.60

were driven during standard operation. When required the electronic control system automatically switched to all-wheel drive, with torque distribution (33:67 favouring the rear axle) and synchronisation by a planetary gear system. If necessary, the rear axle and centre differential were locked in two further stages.

GERMAN MARKS

From 1978 ABS became available as an optional extra for the W 116-series S-Class, the extra cost being DM 2,217.60. Since 1984 ABS has been standard equipment for Mercedes-Benz passenger cars. Ten years after its first introduction, one million Mercedes-Benz cars with ABS were already on the roads of the world.

6.8

1981

LITRES DISPLACEMENT

The “Dernburg Car” of 1907 was the world’s first all-wheel drive car with internal combustion engine, built by DaimlerMotoren-Gesellschaft. From 1908 the vehicle was in operation in German South-West Africa, present-day Namibia. The 35 hp four-cylinder engine with a displacement of 6.8 litres sent its power to the four wheels via a sophisticated mechanical system: A shaft connected it to the precisely centrally installed transmission, providing four forward gears and one reverse gear. From there, propeller shafts transferred the rotary movement to the differentials at the front and rear axles, which in turn distributed it to the wheels via bevelled gears.

Mercedes-Benz also took on the pioneering role in the commercial vehicle sector. ABS for compressed air brakes, a joint development with WABCO, already became available in 1981. Since 1986 the brand’s large touring coaches have been equipped with ABS as standard, and since 1991 also its truck models. Before approval for series production, the anti-lock braking system for trucks and buses was subjected to more than 60 million test kilometres – ABS must be reliable under all circumstances. The markings on the tyres make the effect more easily visible.

100 MILLION KILOMETRES

Before the anti-lock braking system ABS jointly developed by Daimler-Benz and Bosch was mature enough for series production in 1978, MercedesBenz conducted a major trial with 100 test vehicles covering over 35 million kilometres. Only then was the company satisfied with the reliability of the rpm sensors at the two front wheels and at the drive pinion of the rear axle, the electronic control unit and the hydraulic unit.

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As dynamic control systems, the automatic locking differential (ASD), acceleration skid control (ASR) and automatically engaged 4MATIC all-wheel drive celebrated their premiere in the Mercedes-Benz 124 series (1984 to 1997). In the sophisticated all-wheel drive system of the 124 series, the rear wheels

PERCENT

A customer purchasing a Mercedes-Benz with a trailer coupling automatically receives the trailer stabilisation system Trailer Stability Assist TSA as well. The same applies to vans such as the Sprinter. TSA is an additional function of the Electronic Stability Programme ESP®, and ensures more safety when towing a trailer. TSA rapidly and reliably recognises the onset of feared sinusoidal oscillations, and effectively dispels them. To this end it uses the ESP® sensors, and initiates alternating, targeted braking intervention at individual wheels to stabilise the combination.

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DRIVER FITNESS TURNING NIGHT INTO DAY Photo: Martin Harvey/Corbis

OWLS are nocturnal animals with outstanding eyesight and

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hearing. Their large, forward-facing eyes enable them to see objects and prey spatially so that speed and distance can be assessed. The eyes themselves do not move in their sockets – instead owls are able to swivel their heads by up to 270°, which greatly increases their field of vision. Many owl species also have a facial hood that directs sounds towards their ears.

DRIVER-FITNESS SAFETY HAS BEEN A KEY VALUE AT MERCEDES-BENZ FOR SEVERAL DECADES. NIGHT VIEW ASSIST, INTELLIGENT LIGHT SYSTEMS AND THE HEAD-UP DISPLAY ENSURE EXCELLENT VISIBILITY. STOP&GO PILOT, ATTENTION ASSIST AND INNOVATIVE

SUSPENSION SYSTEMS ARE ALSO AMONG RESULTS OF DRIVER-FITNESS RESEARCH.

THE

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DRIVER FITNESS INFRARED Extending the field of vision: Infrared light is invisible to the human eye. It can therefore be used for dazzle-free road illumination at night. An infrared camera then makes the image visible

NIGHT VIEW ASSIST

BETTER VISION WHEN DRIVING AT NIGHT UNBELIEVABLE REALLY – THE CAR SEES MORE THAN ITS DRIVER. TO DO THIS THE NIGHT VIEW ASSIST SYSTEMS FROM MERCEDES-BENZ USE INFRARED LIGHT AND INFRARED CAMERAS. NIGHT VIEW ASSIST HAD ITS WORLD DEBUT IN THE S-CLASS IN 2005.

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DRIVER FITNESS INFRARED

n the latest generation of this assistance system, an additional (longrange) infrared sensor in the radiator grille is added to the well-proven Mercedes-Benz night vision technology. This enables pedestrians to be detected at a distance of up to 160 metres, and animals such as deer, horses or cows at up to 100 metres. Two separate light sources in the headlamps illuminate the road ahead of the vehicle with invisible infrared light. A (short-range) infrared camera behind the windscreen near the rear-view mirror is able to generate

a brilliant greyscale image in the instrument cluster display. As a third-generation night vision system, the new Night View Assist Plus issues a warning in particularly relevant situations

NIGHT VIEW ASSIST PLUS SEES ANIMALS AND PEDESTRIANS (darkness, unlit roads at speeds exceeding 60 km/h) by automatically switching from the speedometer to a brilliant night view image in the instrument cluster display. Pedestrians or animals detected ahead are highlighted in red in this image. In such situations the spotlight function is additionally used to repeatedly

flash pedestrians in the warning zone by means of a special module in the front headlamps. This attracts the driverâ&#x20AC;&#x2122;s attention to the danger, and the person at the road edge is warned at the same time. Animals are intentionally not flashed, as their reaction to light impulses is unpredictable. Pedestrian and animal detection, and the corresponding highlighting, are now also available in urban areas during darkness (illuminated roads, speed less than 60 km/h) if the greyscale image is activated permanently. â&#x2013;

Visibility with night view assist

Visibility with low-beam headlamps

Display in instrument cluster

Pop-up-function

NIGHT VIEW ASSIST PLUS Spotlight function For the first time, the new Night View Assist Plus is capable of detecting not just pedestrians in potentially hazardous positions in front of the vehicle, but animals too. This third-generation night vision system automatically switches the instrument cluster display from the speedometer to a crystal-clear night view image to alert the driver in unlit areas. Any pedestrians or animals detected ahead are highlighted in red in this image, and pedestrians are briefly flashed by a spotlight.

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DRIVER FITNESS HEAD-UP DISPLAY

INFORMATION IN THE DRIVER’S FIELD OF VISION

HEAD UP THE DRIVER RECEIVES TWO FORMS OF INFORMATION AT A GLANCE THANKS TO THE HEAD-UP DISPLAY. THIS IS BEING INTRODUCED WITH THE NEW C-CLASS, AND WILL SOON BECOME A FEATURE OF OTHER MODELS.

tarting with the new C-Class, MercedesBenz is introducing a new level of information for the driver. The head-up display supplements the information in the central display. As in a jet fighter, it projects important information directly into the driver’s field of vision on the windscreen, ensuring that there is less distraction from the road ahead. Neither do the driver’s eyes need to adapt between long and short-

VIRTUAL IMAGE SEEMS TO FLOAT AHEAD OF THE CAR range vision. The system provides information on speed, speed limits, navigation instructions and messages from driver assistance systems. The technology is based on mirror optics and a fullcolour display module with a resolution of 480 x 240 pixels which is driven by high-powered LEDs. They project the virtual image, which measures around 21 x 7 centimetres, into the driver’s field of vision where

it appears to float around two metres away above the bonnet. This means that the driver sees both the mirror image from the generating unit and the real world in front of the windscreen. The resolution of more than 60 pixels per degree of viewing angle ensures a crystal-clear image.

LIGHT DENSITY IS EVEN SUFFICIENT FOR PROJECTION AT NIGHT A light sensor located near the top edge of the roof automatically adjusts the brightness of the head-up display to the exterior lighting conditions. Light densities of 10,000 cd/m² plus can be achieved on sunny days. Since the contrast ratio is better than 1000:1, the system produces a high-quality display even in the dark. The light density provides detailed information about the location and direction of a light beam emitted by a lighting source. It is the photometric measure of what the human eye perceives as the brightness of a surface. The light density describes the brightness of extended, flat light sources. The SI unit

for light density is candelas per square metre (cd/m²). The driver can adjust the height of the virtual image so that it can be easily viewed. On vehicles with a seat memory function this feature stores the individual setting. A range of display content can also be enabled or disabled, and the brightness of the display adjusted individually.

DISPLAY IS INDIVIDUALLY ADJUSTABLE The special head-up windscreen with its wedgeshaped laminated foil eliminates double images produced by reflections on the outer and inner boundary surfaces of the windscreen. It superimposes the secondary image, which is produced on the outer surface, onto the primary image. This offset depends on the particular angle and has been optimised for a driver in a normal seated position. ■

Double information: in addition to the normal view of the road, the driver has a virtual image showing vehicle information projected onto the windscreen in the direct field of vision. The blurred actual image is due to photo technology

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DRIVER FITNESS HEADLAMPS

INTELLIGENT LIGHT SYSTEMS

LET THERE BE LIGHT

s the worldâ&#x20AC;&#x2122;s oldest and best known automotive brand, Mercedes-Benz has always stood for innovations that are designed to benefit customers. LEDs (light-emitting diodes) today represent the state of the art in vehicle

MILESTONES IN MERCEDES-BENZ LIGHTING TECHNOLOGY headlamps. Here is a brief chronology of the most important milestones in MercedesBenz light technology over the past 20 years: 1991: Premiere of xenon headlamps with gas discharge lamps in the Mercedes F 100 research vehicle 1995: Xenon headlamps with dynamic headlamp range control in the E-Class 1999: Premiere of bi-xenon technology in the CL-Class 2003: World premiere of the active light function in the E-Class 2004: World premiere of bi-xenon headlamps with active light function and cornering light function in the CLS-Class 2005: Premiere of Active Night View Assist in the S-Class 2006: World premiere of the Intelligent Light System in the E-Class

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ALL-LED HEADLAMPS Breakthrough with the CLS

LIGHT-EMITTING DIODES (LEDS) HAVE BEEN BOUND TO BECOME THE NORM AS A LIGHT SOURCE FOR HEADLAMPS SINCE THE CLS USED THEM IN THE INTELLIGENT LIGHT SYSTEM FOR THE FIRST TIME. AND THE NEW S-CLASS IS THE VERY FIRST AUTOMOBILE TO DISPENSE ENTIRELY WITH LIGHT BULBS.

Indicator 13 LEDs

Dipped beam - base light 8 LEDs

2010 saw a breakthrough in LED technology. With the launch of the CLS, Mercedes-Benz became the first automotive manufacturer to offer a series-production model featuring dynamic all-LED headlamps incorporating all the adaptive light functions of xenon systems. The lighting specialists at Mercedes-Benz have also for the first time been able to combine this LED technology with the already innovative Adaptive Highbeam Assist, which has resulted in a completely new level of safety at night.

Side light 22 LEDs

Cornering light 2 LEDs

NightView 10 LEDs

Dipped beam-spot 8 LEDs

Main beam 8 LEDs

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DRIVER FITNESS HEADLAMPS

INTELLIGENT LIGHT SYSTEM – CORNERING LIGHTS More safety on junctions 2009: World premiere of the Intelligent Light System with Adaptive Highbeam Assist in the E-Class 2009: Premiere of Active Night View Assist Plus in the S- and E-Class 2010: World premiere of LED High Performance headlamps incorporating all

the light functions of the Intelligent Light System in the CLS-Class 2010: New xenon burner with 20 percent higher colour temperature, and thus even closer to daylight, in the S- and E-Class 2011: World premiere of the spotlight function in conjunction with Active Night

View Assist Plus in the CL-Class 2013: New E-Class fitted as standard with energy-efficient LED low-beam headlamps (34 watts/vehicle) 2013: New S-Class becomes the first car to be equipped exclusively with LED technology as standard

The cornering light is automatically activated if the driver operates the indicators or turns the steering wheel at a speed below 40 km/h. The headlamps then illuminate the side area ahead of the vehicle to a range of around 30 metres at an angle of up to 65 degrees.

ADAPTIVE HIGHBEAM ASSIST PLUS Permanent high beam Adaptive Highbeam Assist excludes recognised road users from the cone of light. If the camera-based system registers either oncoming traffic or vehicles ahead, it will adapt the light distribution according to the traffic situation when high beam is switched on.

INTELLIGENT LIGHT SYSTEM – MOTORWAY MODE Up to 60 percent longer visibility Motorway mode is automatically activated from a speed of 90 km/h. The range of the Motorway mode beams is around 120 metres; in the centre of the light cone, the driver is able to see around 50 metres further than with conventional low beam.

INTELLIGENT LIGHT SYSTEM – EXTENDED FOGLIGHT Less backglare ADAPTIVE HIGHBEAM ASSIST More light improves visibility and comfort at night

The foglamps are active below 70 km/h as soon as the rear foglight is switched on. The headlamp on the driver’s side is pivoted outwards by eight degrees, while the light beam is lowered. This exposes the driver to less backglare.

Conventional systems merely switch between low and high beam. Highbeam Assist presented in 2008 works adaptively, however, and regulates the light distribution of the xenon headlamps as the traffic situation permits. The range of the low-beam headlamps can therefore be increased from around 65 to up to 300 metres - without dazzling other drivers. When the system detects oncoming traffic or cars ahead, it dips the headlamps and continuously adapts the beam range to the distance. 126

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DRIVER FITNESS HEADLAMPS

ACTIVE MULTIBEAM LED The next generation of headlamps Active Multibeam LED takes the situation-based control of the vehicle’s headlamps into a new dimension. Previously, individual functions such as the active light function or anti-dazzle main beam have been controlled mechanically. In the next headlamp generation each LED can be switched on individually, thereby allowing precisely targeted areas to be illuminated. The headlamps are able to adjust their light pattern extremely quickly and unobtrusively – and this can even occur individually for the left and right headlamps respectively. Control units calculate the ideal light pattern 100 times per second.

INTELLIGENT LIGHT SYSTEM – ACTIVE LIGHT FUNCTION Up to 25 metres more visibility on bends

INTELLIGENT LIGHT SYSTEM – COUNTRY MODE Better illumination of the offside road verge

Depending on the steering angle, yaw rate and road speed, the high and low-beam headlamps pivot sideways by up to 15 degrees to considerably improve road illumination.

Country mode replaces low-beam headlamps, and illuminates the road verge on the driver’s side more brightly and widely. This enables the driver to react more rapidly in the dark when other road users cross the vehicle’s path.

The light from LED headlamps is closest to daylight. This means that LED light is in keeping with normal human perception patterns. The closer its colour is to natural daylight, the less artificial light strains the eyes. With a colour temperature of 5500 kelvin, LED light is closer to daylight (6500 K) than xenon light (4200 K).

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The Active Multibeam LED headlamp will see the introduction of roundabout mode as an additional ILS function, and the active light function will be further improved by the use of camera data. Roundabout mode is based on navigation data, and switches on the two cornering lights 70 metres before reaching a roundabout. This gives the driver the best possible road edge illumination when entering, leaving and driving on the roundabout. Pedestrians, cyclists and obstacles can therefore be recognised more easily. In the active light function, information from the camera is used in addition to the steering angle sensor for lane recognition. This enables the light to follow the traffic lane even before the steering wheel is moved. The result is longer-range road illumination when entering and exiting bends.

LEDs are significantly more energy-efficient than regular bulb sets and, depending on the area of application, consume around 75 percent less power. With a higher light output than conventional illumination systems, an energy-saving LED low-beam headlamp, for example, consumes just

34 watts and is therefore much more efficient than a halogen (110 to 120 watts) or xenon light (80 to 84 watts; figures are per vehicle in each case). This means that it is possible to save up to 0.05 litres of fuel per 100 kilometres, or 2.1 grams of CO2 per kilometre, compared to a vehicle with halogen headlamps.

LEDs last considerably longer than regular bulb sets. At 10,000 hours, the average life of an LED is around five times longer than that of a xenon bulb. Since the spring of 2013, the new E-Class has been setting standards in terms of light features: as standard it boasts both low-beam head-

lamps and daytime running lamps which make use of LED technology. In the highly efficient low-beam mode, the two headlamps together have a total power consumption of just 34 watts. All-LED High Performance headlamps are available as an option for the first time in

this class. The new S-Class is the first automobile in the world to be equipped only with LED headlamps, and dispense entirely with conventional light bulbs: almost 500 LEDs are now responsible for illuminating the road, the vehicle, the interior and the luggage compartment. ■

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DRIVER FITNESS HEADLAMP HISTORY Lit up: the old Benz sparkles in the powerful LED headlamps of the S-Class

GOODBYE TO THE LIGHTBULB

BYE-BYE EDISON AROUND 100 YEARS AFTER THE INTRODUCTION OF ELECTRIC LIGHTS FOR AUTOMOBILES, MERCEDES-BENZ IS SENDING OUT A NEW SIGNAL: THE NEW S-CLASS IS THE FIRST CAR IN THE WORLD TO DISPENSE COMPLETELY WITH INCANDESCENT BULBS. THE BENZ 24/40 HP OF 1908 WAS ONE OF THE LAST COMPANY MODELS NOT TO HAVE ELECTRIC LIGHT.

T 1999 CL-Class Bi-Xenonheadlamps 2010 CLS-Class First fully dynamic LED headlamp

1995 E-Class Xenon headlamps 1971 350 SL Halogen headlamps (H4) 1968 300 SEL 6.3 Double Halogen headlamps (H3) 1934 500 K Bilux bulbs 1915 Benz 18 / 45 PS Electric dipping low beam headlamps 1901 Mercedes Simplex Acetylene lamps 1886 Daimler Motorwagen Candle lamps

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2009 E-Class Intelligent Light System with Adaptive High Beam Assist 2006 E-Class Intelligent Light System 2004 CLS-Class Bi-Xenon-headlamps with Active Curve Light and Cornering Light 2003 E-Class Bi-Xenon headlamps with Active Curve Light

2013 E-Class First fully dynamic LED headlamp with Adaptive High Beam Assist Plus

THE EVOLUTION OF LIGHT From the carbide lamp to the all-LED headlamp The inventor of the automobile has also always been a pioneer in the development of lighting. For almost 100 years, incandescent bulbs on the Edison principle were the principal lighting source for automobiles.

he long operating life and a colour temperature similar to natural daylight have long been clear advocates for LED technology. And now Daimler engineers have accomplished a major leap in energy efficiency with the S-Class: power consumption has been reduced by 75 percent compared to conventional headlamps. A breakthrough into the future of lighting, and a farewell to Thomas Alva Edison’s incandescent bulb technology. A hundred years ago, the introduction of electric lighting was a major innovation. Until then carbide lamps provided illumination, but were not entirely uncomplicated. In the stately Landaulet version of the Benz 24/40 HP delivered from Mannheim to Argentina in 1908, which remained in use there until 1966, the gas generator was located in a wooden box on the left-hand runningboard. Water was added to generate acetylene gas from the calcium carbide, and copper tubing fed this to the headlamps which were ignit-

ed by the chauffeur. The light from the flame was projected forward by reflectors. Afterwards, incandescent bulbs on the Edison principle became the principal lighting source for automobiles for 100 years. A thing of the past: in the new S-Class almost 500 LEDs provide the lighting for the road, the vehicle, the interior and the boot. They require less energy by far for the same light output. The new, energy-saving LED low-beam headlamps require only 34 watts, and are therefore much more efficient than halogen light (120 watts) or xenonlight (84 watts, figures are per vehicle). New, powerful single-chip LEDs and a newly developed projection module in the headlamp, where light rays are diverted, reflected and projected outwards, make a significant contribution to the increased efficiency. ■

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DRIVER FITNESS RESEARCH

CUSTOMER RESEARCH CENTER (CRC)

FOCUS ON DRIVERFITNESS DRIVER-FITNESS SAFETY IS A MAJOR COMPONENT OF THE MERCEDES-BENZ CORE BRAND VALUE “COMFORT”. THE CUSTOMER RESEARCH CENTER SCIENTIFICALLY EXAMINES WAYS OF MINIMISING STRESSES FOR CAR

Trials: driving simulators have been available since 1985. They combine driving tests with a laboratory situation

DRIVERS. THIS RESEARCH ALSO INCLUDES NOISE AND VISIBILITY TESTS IN THE WIND TUNNEL.

omfort is also conducive to safety. Studies by the Customer Research Center (CRC) at Mercedes-Benz show that certain comfort attributes have a direct influence on driver performance and well-being during and after a journey. Research into driverfitness safety has been a key task of the CRC for over 15 years. Highly reputed international scientists are regularly invited to the company to document the current status of research into

e.g. acoustic comfort, vibration comfort and climatic comfort, and to analyse the effects on human mental and physical performance.

TAILBACKS ARE A MAJOR STRESS FACTOR

The typical approach taken by the CRC studies on performance-enhancing comfort is initially to register the customer-related influencing factors. Findings on the subject of “long-distance journeys” are obtained by means of detailed custom-

Wired up: the stresses are registered by physiological measurements

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TESTS WITH VOLUNTEERS Taking the measure of car drivers For more than 15 years the Customer Research Center at Mercedes-Benz has examined the stresses acting on car drivers. To this end tests are conducted in the driving simulator and on the roads, under real conditions and with specially prepared vehicles. Typical measurements carried out on volunteers e.g. include the following data: 1 Pupil test before and after the journey 2 Tension in the neck muscles 3 Online survey during the journey 4 Heart rate 5 Tension in the arm muscles 6 Electrical skin conductivity at foot level

Monitored: fitness is measured during a real test drive

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DRIVER FITNESS RESEARCH

Visibility comfort: fluorescent liquids make soiling clearly visible in the important areas. The channeling of dirty water is optimised

er surveys in e.g. Germany and the USA. One of the main findings is that uncertainty about events during a journey, e.g. traffic tailbacks, is a significant stress factor. The second phase involves extensive practical driving tests to systematically examine the influencing factors for their relevance to performance-enhancing comfort. For example using three externally identical E-Class test cars which noticeably but by no means dramatically differ in their

Working with the wind: smoke trails make the wind visible

PREVENTION OF SOILING Keeping things clean Having the best possible visibility in all conditions makes a contribution to Active Safety. In the wind tunnel the aerodynamic specialists optimise components with the help of a fluorescent liquid which makes the soiling clearly visible. The aim is to direct water away so that the side windows and exterior mirror lenses remain clean. This is influenced by the geometry of the A-pillar with its integral components and the geometry of the exterior mirrors and window frames, or trim strips in the case of frameless doors.

FROWNING AS AN INDICATOR OF DISSATISFACTION vibration and noise comfort, and which have different driver seats. 36 MercedesBenz customers with long-distance driving experience were sent on a 410-kilometre long circular route covering motorways and country roads in each of the cars, and this route was completed three times. The fitness of the test subjects during and after the journey was assessed using a number of indicators. During the journey, the heart rate was monitored together with muscular tension in the neck area and the frequency of frowning as an indicator of dissatisfaction. The con-

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centration of the hormone cortisol in the saliva gave an indication of stress levels. Directly after the journeys the test subjects were subjected to performance and alertness tests to assess their level of fitness. They were also asked to complete questionnaires and assess their level of fatigue, for example. Indirect indicators also taken into account included the average driving speeds and especially the

length of the breaks taken by the drivers. Dr Götz Renner summarises the conclusions from the research as a “recipe

A RECIPE FOR PERFORMANCEENHANCING VEHICLES for performance-enhancing vehicles”: “Build a quiet vehicle, especially avoiding the low frequencies, add a

good (driver’s) seat and firstclass climate control. Plan and schedule routes and rest breaks while avoiding tailbacks, entertain the driver, create the fundamental conditions for relaxation and assist them with functions such as the ENERGIZING massage function so that they can cope with stress and fatigue. This vehicle will then have a fit and alert driver – even after the journey.” ■

Acoustic comfort: the task of the aeroacoustic specialists in the wind tunnel is to minimise the frequency and intensity of obtrusive noises

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DRIVER FITNESS DROWSINESS

ATTENTION ASSIST

PREVENTING FATIGUE

Indicator: an angle sensor in the steering wheel registers changes in behaviour

ATTENTION ASSIST Measuring fatigue The key indicator of increasing drowsiness is a change in steering behaviour. ATTENTION ASSIST measures this with a high-resolution steering wheel angle sensor. During tests with over 670 male and female car drivers over the development period, Mercedes-Benz scientists found that overtired drivers have difficulty in keeping the vehicle precisely in its lane. They make small steering errors which are often corrected quickly and in a characteristic manner. 70 further indicators are also evaluated.

IN GERMANY DROWSINESS IS THE CAUSE OF ONE QUARTER OF ALL MOTORWAY ACCIDENTS. IN 2009 MERCEDES-BENZ PRESENTED ATTENTION ASSIST, WHICH IS ABLE TO DETECT SIGNS OF DROWSINESS USING A LARGE NUMBER OF PARAMETERS.

Warning: the central display recommends a break, and also tells the driver where

Monitored: the test subjects were carefully monitored during the development of ATTENTION ASSIST. Today the system gives a timely warning of dangerous microsleep

TTENTION ASSIST developed by Mercedes-Benz registers over 70 parameters which are evaluated for drowsiness detection. This continuous monitoring is necessary to register the transition from wakefulness to drowsiness, and to warn the driver in good time. Based on this wealth of data, ATTENTION ASSIST

calculates an individual driver profile during the first few minutes of every trip. This profile is then compared with the current sen-

ment cluster: “ATTENTION ASSIST. Break!” In 2013, it was systematically developed further, and the latest version has the

A CLEAR WARNING WHEN DROWSINESS SETS IN: TAKE A BREAK! sor data and the prevailing driving situation by the car’s electronic control unit. If the system detects drowsiness, it emits an audible warning signal and flashes up an unequivocal message on the display in the instru-

ability to detect drowsiness and inattentiveness across a far greater speed range from 60-200 km/h. Furthermore, the system’s sensitivity can be adjusted, for example

for drivers who already feel tired when they take the wheel. A new menu in the instrument cluster display also makes the system more tangible and transparent for the driver by visualising the current ATTENTION ASSIST level and the driving time since the last break. If the usual ATTENTION ASSIST warning recommending the driver to take a break is emitted, nearby service areas can be indicated in the navigation system. ■ Premiere: in 2009 the E-Class was the world’s first automobile to feature a drowsiness warning system as standard

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DRIVER FITNESS STOP&GO PILOT

MORE COMFORT IN TAILBACKS

THE CAR BRAKES, ACCELERATES AND STEERS

ar owners have wanted this for a long time: a car that relieves the driver of stress when tailbacks slow things down and individual mobility loses its sparkle. The development of Stop&Go Pilot began in 1998 with the active cruise control system DISTRONIC - using radar, the S-Class maintained the set speed or the distance from the vehicle ahead. DISTRONIC PLUS went one better by being able to brake to a standstill. Following tailback traffic has now been perfected with Steer Assist. The radar-based basic function has now been extended by Steer Assist with Stop&Go Pilot, which assists the driver with lateral guidance of the vehicle. The sys-

STEER ASSIST KEEPS THE CAR ON TRACK

RELIEVING THE STRESS OF STOP & GO TRAFFIC: DISTRONIC PLUS WITH STEERING ASSIST AND STOP&GO PILOT TAKES THE BURDEN OFF THE DRIVER WHEN IT COMES TO LANE GUIDANCE, AND IS ALSO ABLE TO FOLLOW VEHICLES IN TAILBACKS SEMI-AUTONOMOUSLY.

tem helps the driver to keep the vehicle in the middle of its lane by generating a steering torque when driving in a straight line or even on slight bends. The stereo camera recognises lane markings as well as vehicles driving ahead together with their spatial positioning, and relays this information to the electric steering assistance system. By generating the appropriate steering torque, the system can enhance ride comfort in the speed range up to

200 km/h and greatly assist the driver in many traffic situations. At speeds up to 60 km/h, the Stop&Go Pilot ‘intelligently’ decides whether to use the vehicle in front or the road markings as a means of orientation, enabling semi-autonomous tailback tracking even when there are no clear lane markings visible. The system fuses the data gleaned from the stereo camera and the radar sensors, calculates any reactions required, and then regulates the vehicle’s linear speed as requirements dictate by controlling engine power, transmission and brakes, as well as actuating the electric steering for lateral vehicle guidance. DISTRONIC PLUS with Steering Assist can be activated as before with a stalk on the steering column in a speed range from 0-200 km/h, now also with the vehicle standing still and no vehicle moving ahead of it. Any speed between 30 km/h and 200 km/h can be selected as the desired cruising speed. The driver starts off in this case by pulling the DISTRONIC PLUS stalk or tapping the accelerator. A green steering wheel symbol appears in the instrument cluster to indicate when Steering Assist is operating while DISTRONIC PLUS is activated. Meanwhile, linear controlling actions (cruise control function) continue to be visualised in the speed display by means of circular segments and the speedometer needle.

The system’s design is so refined that the sensors can detect whether the driver’s hands are on the steering wheel. If the system recognises that the driver has taken his/her hands off the steering wheel while the car is moving, depending on the situation, the detected surroundings and the speed, a visual warning is first is-

THE DRIVER’S HAND MUST REMAIN ON THE STEERING WHEEL sued in the instrument cluster; then a warning signal sounds and Steer Assist is deactivated. This is additionally indicated by changing the steering wheel symbol from green to white. The linear control action remains unaffected by this and continues to be available. This means that the system has an intelligent hands-off detection feature that brings the driver’s hands back to the wheel when necessary. The use of DISTRONIC PLUS makes life easier for drivers in tailbacks – at low speeds they can even drive handsfree, without compromising safety. Thus Mercedes-Benz offers relaxed driving mainly over long distances and on motorways, especially during otherwise tiring and annoying (slow) tailback driving. The performance capabilities of the basic DISTRONIC PLUS function have been increased once again. Now the

Preset speed: DISTRONIC PLUS accelerates up to 200 km/h and brakes, even to standstill in stop & go traffic

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system is able to brake at a rate of up to 5 m/s² without any intervention from the driver. If the “S” transmission mode button is pressed, the rate of acceleration increases too. Vehicle acceleration is also far more dynamic if the driver signals a wish to overtake by switching on the indicators, assuming the adjacent lane is clear. By combining the radar and camera data, DISTRONIC PLUS is now also able to detect both vehicles cutting in and vehicles ahead, and

vehicles ahead of them, in one’s own lane and in adjacent lanes, and take any necessary action promptly. This can prevent, for example,

DISTRONIC PLUS PROTECTS AGAINST INSIDE PASSING illegal overtaking on the inside lane on motorways and similar multi-lane highways by adapting the speed to that of vehicles in the outside lanes (at speeds above 85 km/h), especially when

a tailback begins to dissolve and in streams of traffic. At lower speeds, permissible overtaking on the inside lane with a maximum speed differential of 20 km/h is possible. It goes without saying that drivers can always override DISTRONIC PLUS with Steer Assist. For instance if they signal with their indicators that they wish to change lanes, the lateral assistance remains passive for as long as it takes to change lanes. ■

Virtual reality: the tailback driving assistant still seemed Utopian in the F800 Style research vehicle (2010), but now it is a reality

DISTRONIC PLUS WITH STEER ASSIST Comfort in tailbacks Steer Assist extends the radar-based basic function of DISTRONIC PLUS. The system helps the driver to keep the vehicle in the middle of its lane by generating a steering torque when driving in a straight line or even on slight bends. The stereo camera detects road markings and a vehicle in front and then forwards this information to the electric power steering. This enables the Mercedes to follow the vehicle ahead in a tailback, even if no clear lane markings are visible.

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Early trials: approaching the vision of accident-free driving. Active cruise control undergoing trials as part of the Prometheus research project (1986)

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THE WORLD’S FIRST SUSPENSION SYSTEM WITH “EYES”

FLYING CARPET WITH THE HELP OF A STEREO CAMERA, MAGIC BODY CONTROL WITH ROAD SURFACE SCAN RECOGNISES UNDULATIONS AND BENDS IN ADVANCE, THE SUSPENSION VARIABLY ADJUSTS ITSELF TO NON-LEVEL STRETCHES AND WITH THE NEW CURVE INCLINATION FUNCTION THE CAR ELEGANTLY LEANS INTO THE BEND.

ercedes-Benz has always sought the ultimate ride comfort with its innovative suspension systems. In 1961 air suspension had its debut in the 300 SE, and from 1964 its comfort also impressed in the model 600. To this day AIRMATIC guarantees outstanding suspension comfort – not only in the S- and E-Class, but for the first time now also in the new-generation C-Class. Active Body Control (ABC) comes even closer to the ideal of a flying carpet this active suspension system first became available in 1998. Apart from its springing and damping function, this electrohydraulic suspension system based on steel springs allows pitching and rolling movements of the vehicle to be compensated.

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As the vehicle is kept horizontal by the hydraulic system, ABC models need no conventional stabilisers, which is unique in automobile engineering. In the new S-Class, Mercedes-Benz makes use of the fast reaction time of an ABC suspension in combination with the innovative ROAD SURFACE SCAN func-

ABC SUSPENSION REACTS ALMOST INSTANTLY tion. This is able to recognise undulations in advance, and the suspension responds predictively. The result is unprecedented ride comfort. The “eyes” for the ROAD SURFACE SCAN function are provided by a stereo camera fitted behind the

windscreen, which scans the road up to 15 metres ahead of the vehicle and delivers a precise image of the road contours. Based on the camera pictures and driving status information, the control unit constantly calculates the best control strategy for overcoming unevenness such as prolonged bumps. This means that in advance, and for each individual wheel, the vehicle is able to select stiffer or softer damper settings and use the active hydraulics to vary the load at each wheel. The suspension is adapted to the relevant situation within fractions of a second, enabling body movements to be considerably reduced. As ROAD SURFACE SCAN is camera-based, it works in the daytime, in good visibility, with suitable surface structures and at speeds up to 130 km/h.

Brain centre: the information is processed and the control unit gives precise instructions to the wheel suspension

Undulation: when undulations are recognised the suspension adjusts itself in advance – body movements are prevented

Magic eye: the stereo camera scans the road surface ahead to a distance of up to 15 metres and reports undulations

Suspension strut: each wheel has an individually adaptable spring/damper unit. The spring pretension is hydraulically adjusted in fractions of a second

ROAD SURFACE SCAN The suspension reads the road ahead The new S-Class is the first car in the world able to recognise road surface undulations in advance. Once ROAD SURFACE SCAN has detected such undulations with the help of the stereo camera, the suspension system MAGIC BODY CONTROL adjusts the damping at each individual wheel in advance for a softer or harder setting and uses the active hydraulics to increase or lessen the load on the wheel. The result is unprecedented ride comfort. As ROAD SURFACE SCAN is camera-based, it works in the daytime, in good visibility, with suitable surface structures and at speeds up to 130 km/h.

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In the Active Body Control system from MercedesBenz, the four spring struts are equipped with hydraulic cylinders (plungers) to adjust the force in each spring strut individually. This means that the system can almost completely compensate for lifting, rolling and pitching of the body. The control unit receives information on the current driving situation from various acceleration sensors and then compares these data with those from the pressure sensors in the spring struts

and the level sensors on the control arms. The system then computes the control signals for the servo-hydraulic valves at the front and rear axle to ensure precisely metered oil flows.

CROSS-WINDS ARE ALSO COMPENSATED Once oil flows into the plunger cylinders, this modifies the tracing point of the steel springs integrated into the spring struts, generating

the necessary force to counteract the body movements. Thanks to a constantly available hydraulic pressure of up to 200 bar, ABC is able to stabilise the body within fractions of a second. Cross-wind stabilisation is a further function of Active Body Control. When the control detects a strong gust of wind, the wheel load distribution is changed in fractions of a second. This creates a yawing motion of the vehicle which considerably reduces the effect of the cross-wind.

The curve inclination function in the new S-Class Coupé is another world first for series production automobiles. The vehicle leans into bends in a similar way to motorcyclists or skiers. The lateral acceleration acting on the occupants is reduced as when passing through a high-bank curve, and they sit more firmly in their seats. Especially on country roads, the new curve inclination function means more driving pleasure and comfort. The aim is not to achieve higher cornering

speeds, but a new driving experience: the S-Class Coupé glides elegantly through bends.

THE CAR LEANS INTO THE BEND LIKE A SKIER Depending on the bend to be negotiated, the curve inclination function modifies the base points of the relevant suspension struts. This means that in fractions of a second, the vehicle continuously leans into the bend to

an angle of up to 2.5 degrees – depending on the bend radius and road speed. This innovative system recognises bends with the help of the stereo camera behind the windscreen, which registers the curve in the road surface up to 15 metres ahead, and using an additional lateral acceleration sensor. The curve inclination function can be selected using the ABC switch, and is active in a speed range of 30 to 180 km/h. ■

Suspension comfort: coping serenely with road surface defects has always been a strength of saloons from Mercedes-Benz

CURVE INCLINATION FUNCTION More fun on bends The ABC system (Active Body Control) independently regulates the oil-flow to the suspension struts at each wheel. The base point of the spring is adjusted. This influences the movement of the vehicle body. The new curve inclination function actively responds to bends recognised by the camera and a special lateral acceleration sensor: the body leans into bends at an angle of up to 2.5 degrees, depending on the bend radius and speed. The result is a completely new driving experience, with a reduction of lateral force for the occupants.

Gliding through bends: the vehicle leans elegantly into the bend, the occupants enjoy a surprisingly new cornering experience

Wheel actuator: each suspension strut is individually adjustable by the hydraulics – the base point of the spring is modified Safely on track in cross-winds: modifying the wheel load distribution counteracts the gust of wind – the vehicle remains on course

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DID YOU KNOW?

LEDS

Consideration for other road users: with so-called multi-level functionality, Mercedes-Benz has achieved another world first in the tail lights of the new S-Class. The 35 LEDs per light cluster (brake lights and indicators) are operated with varying light intensity, depending on the driving situation and ambient lighting (day/night). If the Mercedes-Benz driver presses the brake pedal while stopped at traffic lights at night, for instance, the brightness of the brake lights will be automatically dimmed to avoid dazzling anyone behind.

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Only 20 percent of car journeys are at night, but they account for 40 percent of fatal accidents - one of the shocking findings by Mercedes-Benz accident research. According to a study by the German Federal Agency for Road Affairs (BASt), five times as many pedestrians are killed on country roads at night as during the day.

SENSORS

In April 2010 two Mercedes-Benz trucks set off for a historic comparative test drive: the Actros and LP 1620 were separated by 50 years. The aim was to measure driver stress. Each driver wore an EEC cap with 16 sensors. These were used to register brain impulses and measure response. The result was that the slower processing of impulses in the LP 1620 amounted to up to 400 milliseconds compared to the Actros. However, if this value is applied to the sequence “signal-preception-reaction” or e.g. “seeing brake lights, consciously perceiving them and taking braking action oneself”, it means that in a truck travelling at 80 km/h braking action is taken nine metres later.

PERCENT

Insurers have recognised that assistance systems help to prevent accidents or mitigate their consequences. This also pays off financially for Mercedes-Benz drivers: customers ordering the Driving Assistance package Plus (with the functions DISTRONIC PLUS with Steer Assist and Stop&Go Pilot, Active Blind Spot Assist and BAS PLUS with Cross Traffic Assist) can save 15 percent on their insurance premium.

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ACTUATOR MOTORS

QUESTIONS

In the mid-1960s the subject of automobile safety became a matter of public concern in view of increasing accident figures. Mercedes-Benz responded with advertisements, asking: “Would you rather have a safe car and no dreams than a dream car without safety?” Item 4 is particularly interesting: driver-fitness safety was already in the book of specifications for Mercedes engineers at that time.

As standard, the front seats of the new S-Class are electrically adjustable for travel, height, inclination and seat cushion depth. With full specifications, up to nine seat adjustment motors bring each of the front seats and EASY ADJUST luxury head restraints into the ergonomically right position. Plus there are six seat ventilation motors. In the rear there can be up to twelve motors per seat. All in all, therefore, up to 54 actuator motors take care of the seating comfort of occupants in an S-Class, while two further motors move the steering wheel to the desired position. The seats are adjusted with the help of a design icon: since 1981 the switch has been in the form of a miniature seat.

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WAS ALSO TAKEN INTO ACCOUNT FROM AN EARLY STAGE. ANALYSING REAL ACCIDENTS LED TO THE

OFFSET CRASHS. ANOTHER SYSTEMATIC POINT OF FOCUS ARE CAR VERSUS CAR ACCIDENTS.

STANDARDISATION OF

IMPACT AT 50 KM/H BISON fighting and each weighing up to 900 kg are reminiscent of the forces involved in a crash test. Nature neglected to provide a crumple zone

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CRASHES. FROM THE START, NOT JUST COLLISIONS WITH A SOLID BARRIER HAVE BEEN A POINT OF FOCUS, BUT SAFETY IN THE EVENT OF A SIDE IMPACT ATICLY TESTING CARS IN

Foto: Donald M. Jones/Minden Pictures/Corbis

FOR 55 YEARS MERCEDES-BENZ HAS BEEN SYSTEM-

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500 CRASH TESTS EVERY YEAR

ORGANISED DESTRUCTION WHAT HAPPENS IF AN ACCIDENT CANNOT BE AVOIDED? SINCE THE 1950s MERCEDES-BENZ HAS CONDUCTED A SOPHISTICATED SERIES OF TESTS INTO THE CRASH PERFORMANCE OF ITS CARS, FAR EXCEEDING THE TESTING REQUIRED BY LAW.

Small versus large: lightweight, compact cars are at a disadvantage in the event of an accident if they collide with a considerably heavier car. Mercedes-Benz designs the bodywork structure of large vehicles to absorb part of the impact energy of the other vehicle thus improving the situation for the small vehicle

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he first impact tests carried out by Mercedes-Benz as early as the late 1950s were spectacular: winches or hot-water rockets were used to propel the cars. For the roll-over test, the technicians built a corkscrew ramp and, for lack of dummies, the

engineers took part in some tests themselves. Crash tests still form the basis of safety developments at Mercedes-Benz. These days, however, vehicles are accelerated by means of a high-tech cable pulley system. Every year some 500 impact tests of this kind are carried out at the development centre in Sindelfingen.

Altogether, new MercedesBenz cars must currently pass almost four dozen different crash tests. This is because, as part of an integrated approach to “Real Life Safety”, MercedesBenz not only performs crash tests in collision configurations prescribed by rating tests and for international registration – crash

Side impact with deformable barrier: standardised re-creation of a cross-traffic accident. The camera on the bonnet documents what happens

Front impact against deformable barrier: standardised re-creation of a rear-end collision at high speed

REAL LIFE SAFETY Unusual crash tests As part of an integrated approach to “Real Life Safety”, Mercedes-Benz not only performs crash tests in collision configurations prescribed by rating tests and for international registration – traditionally the test programme has also included MercedesBenz test set-ups derived from in-house accident research. At the world’s biggest commercial vehicle manufacturer, these obviously extend to collisions with trucks as well as overturns involving roadsters and cabriolets. At frequent intervals this resulted in test configurations being adopted subsequently in legislation. E-Class versus Actros: when the big saloon becomes the smaller party

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A “pagoda” overturns: the SL is tipped over with some force

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1962: the “Fintail”, the first car with safety body, hits a bus at 86 km/h

BEYOND BARRIERS Crashing car versus car

1968: old versus new S-Class. Early on, side impact protection becomes a further focus of development 2004: the smart fortwo’s tridion safety cell demonstrated its protective effect in a crash test against an E-Class

tests are also derived from in-house accident research by Mercedes-Benz. Requirements here often go far beyond those stipulated by legalisation. At times these have set the standard across the automotive industry: in 1979, for example, the offset crash was introduced inhouse as a test method that closely approximates reality. Engineer Wolfgang Schwede from the testing department: “Analysis of types of frontal collision occurring on the road shows that (with righthand traffic) collisions offset to the left occur most frequently at 50 percent, whereas the collision test

prescribed by law occurs only 25 percent of the time.” A frontal impact with a contact ratio of 40 percent places enormous stress on the occupant cell. To transfer the forces, engineers devel-

MERCEDES-BENZ PIONEERED THE OFFSET CRASH oped the concept of three load paths: the longitudinal forces resulting from the impact are transferred to the sidewall, tunnel and floor. These days, the offset crash is an established legal requirement worldwide.

Until the methodology and collision configurations could be defined, this work was trial and error. Within Europe, crash testing in the 1950s represented an entirely new field. Engineers at Daimler-Benz closely watched developments in the United States as crash tests became established there as a new research and development tool. Visits to American universities and automotive manufacturers gave experts from Stuttgart useful ideas for their own component experiments and crash tests. They learned to tackle safety issues head-on. Why? Because the engineers were

Mercedes-Benz started crash testing as early as 1959. In the decades that followed standardised tests were designed against barriers. These became established worldwide and found their way into law. Right from the start, accident experts in Sindelfingen were also interested in what happens during real accidents. By the early 1960s, cars were already being crashed into each other or buses in order to reconstruct the reality of such accidents. Here too it took some time for criteria to be defined based on findings from research into real accidents which would then influence crash test parameters.

1988: 190 (W 201) versus 200 (W 124). The real side impact shows the development advances which have been made

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convinced that the sharp rise in the number of accident victims was not inevitable. It was up to them to make cars safer. However, for a long time they did not have nearly enough knowledge. Compared with evaluating a car damaged in an accident, the major benefit of a crash test lies in the ability to record every detail of the actual collision in sequence. The analysis equipment for this was developed in the years prior to 1959. It included acceleration sensors in dummies and

in the test vehicle itself, as well as high-speed films so that the images needed to analyse the collision could be slowed right down.

TESTING THEN CALLED FOR IMPROVISATION Originally the spectacular vehicle tests were conducted outside. The necessary tools to carry them out were relatively simple from today’s perspective. Improvisation was the order of the day. A

table would be used as a camera stand or the roof of the measurement bus would serve as an observation platform. Filming the course of a collision using high-speed cameras is particularly difficult with variable amounts of cloud. For example, the aperture could be set for sun and the rocket would be ready to go but a small cloud in front of the sun could persistently cast a shadow over the test site. Given the rising number of crash tests and high demand for the results of such

1989: the offset crash was an important step. Here a 300 SL (R 129) undergoes testing. Thanks to the inspection pit, the process can also be filmed from below

1968: once the methodology was in place, the researchers wanted to know how early models behave – this is a 170 S from 1951

THE EVOLUTION OF BARRIERS Acid test: the offset crash Originally, tests were conducted with full contact against a solid barrier. This was later stipulated by legislation, too. Mercedes-Benz accident research, however, showed that offset collisions were twice as common. From 1979, therefore, internal tests were carried out with a contact ratio of 40 percent. In terms of occupant cell stability, this is a tough challenge: a collision at 55 km/h stands for a crash with oncoming traffic. Today a modified offset crash is an established requirement, worldwide. 1987: Coupé C 124 versus a skewed barrier (30° angle), a legal requirement in the USA

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experiments, it was clear by the late 1960s that capacity and resources at the old test track in Sindelfingen were too restrictive. A new accident test centre was built in Sindelfingen between 1971 and 1973. The safety researchers initially installed what is known as a Bendix sled for the purposes of accident simulation. To achieve the same accelera-

tion as in a real accident, this sled is not slowed down. Instead it is accelerated, meaning that the direction of movement is reversed. In 1972 work began on building a new crash facility. This would make it possible to examine frontal and side collisions, as well as overturns. High-speed cameras now recorded the whole crash under very bright lights and

Ready to ruin: an SLK is prepared for crash testing in 2010. A winch accelerates it into the obstacle

CHANGES TO PROPULSION From rocket to linear motor Initially cars were accelerated using a cable winch. Engineers borrowed the towing technology from glider pilots at Stuttgartâ&#x20AC;&#x2122;s technical university. From 1962 onwards, a hot-water rocket provided propulsion on the test track, which was by now built of concrete. The rail-mounted rocket accelerated the test vehicle to the desired speed and was then slowed down. Over in the new crash hall, 1973 saw the introduction of a linear motor to propel the test vehicle down a 65-metre test track with the force of 53,000 newtons. The unit accelerated cars to the target speed along the first half of the track, regulated the speed to the desired level along the remaining section and decoupled in time before the collision occurred. From 1998 onwards, the modernised test centre switched back to using a sophisticated cable pulley system for acceleration purposes. This made it possible to accelerate two vehicles simultaneously for the car versus car tests.

Track extension: the crash track was 100 metres long for the 600 model

NEW CONSTRUCTION

SAFETY CENTRE Work on the new vehicle safety technology centre started in July 2013. Following investment worth hundreds of millions of euros, the new building in Sindelfingen is scheduled for completion in mid-2016 and will be 273 metres long, 172 metres wide and up to 23 metres high. With floor space totalling 55,000 square metres, the vehicle safety technology centre will have a test hall covering 8,100 square metres. On rails: the track-guided rocket has been used to accelerate test vehicles since 1962. When decoupled, the test vehicle rolls into the obstacle, unpowered

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Indoor testing: from 1973 crash tests were conducted inside a hall. The new aspect: an electric system of propulsion

Plan: how the new safety centre in Sindelfingen will look in 2016

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from various different vantage points. While the human eye can process only 16 images per second, this high-tech equipment can handle some 1000 images per second. Because the cameras are, of course, digital there is no more waiting for the film to be developed. A crash test takes just milliseconds, whereas evalu-

ating the data takes several days. What got broken underneath the metal of a virtually unscathed (outwardly at least) preproduction model? And why? What was the load on the dummies? Twice a day, the “accident detectives” are fed new information. “In addition to around 500 crash tests carried out each year, more

than 50,000 computer simulations are generated,” explains Head of Crash Testing Ferdinand Gaiser. Although realistic simulation saves on iterative loops, it can by no means replace conventional testing – of that the engineer is certain: “As a bridge between simulation and reality, the crash test will not be superseded any time soon.”

Rocket truck: the hot-water rocket brought even this heavily laden truck up to speed for crash barrier tests

Breaking through the crash barrier: it was not planned for this “Fintail” to burst through the boundary during crash barrier testing

PLANK TEST Staying on the road At the Sindelfingen vehicle testing site, numerous tests were conducted for the German Federal Ministry of Transport from 1962 to 1968 to test and specify the crash barriers which are still in use today. Alternatives were tried out, such as steel cables tensioned between posts, but these were not able to withstand colliding trucks. For the crash barriers, it soon became apparent that firm anchoring was needed to withstand impact forces. As can clearly be seen from the photograph above, photographic documentation of crash tests still depended greatly on the photographer’s ability to react. It is also interesting to note the number of construction cranes in the background working to extend the Sindelfingen body plant. Testing materials: side crash in 1970 against the plastic body of the C111 research vehicle

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DATA ANALYSIS Recording on tape When the new crash facility opened in 1974, modern electronics also found their way into safety development. Until that time, analogue data was transferred to the crash vehicles via trailing cables. Due to the increasing number of measuring points, these were getting thicker and more unwieldy all the time. The new frequency-division multiple access system featuring integral data storage remedied this situation by relaying four to ten times the amount of data per cable. It was also now possible to save the measured data on tape prior to systematic analysis.

Bogie: twice a day, a crash test takes place. Head of Crash Testing Ferdinand Gaiser analyses the results

“No one experiences as many accidents as us,” says Gaiser who has worked for Mercedes-Benz since 1991. The cars are not always new: for example, out of interest, some years ago Gaiser and his colleagues crashed a vehicle from the world’s first model series to be fitted with airbags (W 126). An official car of former Chancellor of Germany Helmut Kohl,

a V 140 model S-Class, also breathed its last breath in the crash test hall in Sindelfingen. Increased safety will continue to be a key developmental goal at Daimler into the future. For that reason, the company is investing hundreds of millions of euros in a new vehicle safety technology centre due for completion in 2016. Construction in Sindelfingen

commenced in July 2013. As well as concentrating on passive safety, special attention will be paid here to the requirements posed by new alternative drive system concepts and vehicle technology. Further research and development work will also be conducted here into the potential of PRE-SAFE® and assistance systems in the pre-accident and crash phase. ■

Control room: using state-of-the-art technology, from 1974 data was recorded onto magnetic tape for subsequent evaluation

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MOCK-UP HUMANS

THEY SUFFER FOR US TEST DUMMIES MODELLED ON THE HUMAN BODY PROVIDE INSIGHTS INTO THE STRESSES AND STRAINS WHICH APPLY IN AN ACCIDENT. AS SUCH, CRASH-TEST DUMMIES SYMBOLISE ACCIDENT RESEARCH PER SE.

he great advantage of a crash test as opposed to analysing cars which have been involved in accidents lies in the possibility of tracing the actual course of the collision in full detail. The necessary analysis technique was developed in the 1960s. It involves dummies which represent the human body. The initial dummies to be employed had been developed for tests in the aviation industry. They already incorporated load cells to record acceleration values. The first dummy created specifically for the automobile industry

was the VIP 50 model from Alderson Research Laboratories. The Daimler engineers called their first dummy “Oskar” and kept it in use for almost 30 years. The front passenger seat was

DUMMY OSKAR SPENT 30 YEARS IN RIGOROUS SERVICE initially occupied by sandbags and shop window dummies - which failed to yield much in the way of findings. The dummies’ dimensions and the employed measuring methods quickly diversified and abandoned the standard set by the VIP model, howDummies with keen senses: Sensors inside the dummy record over 30 different items of data and save them on a data recorder. Sensors and data memory are checked during preparations for a crash test. After the crash, the data are read out and undergo further processing

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ever: the 1960s saw the emergence of dummies which had proportions corresponding to the average for men, women and children and which were fitted with flexible joints. The measuring accuracy for certain test set-ups also underwent continual improvement – in addition to passenger dummies, a test dummy was also introduced for re-creating accidents involving pedestrians. Dummies were additionally developed to enable particularly accurate assessments of specific accident scenarios. Today’s industry standard is defined by dummies of the Hybrid III family, which was developed by General Motors

in 1976. These constructions consisting of metal, plastic and foam are fitted with numerous measuring probes and cost up to 150,000 euros. Hybrid III is also subject to ongoing development and

ACCELEROMETERS AND FORCE SENSORS PROVIDE INSIGHTS can be fitted today with a whole range of sensors in the head, neck, chest, spine, pelvis and legs. Accelerometers and force sensors are the most commonly used fittings. Other standard items are angle gauges for the knee and angular velocity sensors for the head.

Family get-together: Different dummies are used for different tests. Many still transfer their data by cable

DUMMY DEN Where the dummies live The original Hybrid III dummy, which was presented in 1976 as the “50 percent man”, has since acquired an entire family of dummies in many different variants covering different sizes and weights. As the 50 percent man (H III 50%) it measures 175 cm in height and weighs 78 kg, representing the average male car driver. Its big brother (H III 95%) is 188 cm in height and weighs 101 kg. H III 5% represents a short woman (152 cm / 54 kg). There are also three Hybrid III child dummies representing children with a body weight of 16.2 kg (for three year-olds), 23.4 kg (for six year-olds) and 35.2 kg (for ten year-olds). Not fit for purpose: The originally employed shop window dummies failed to make the grade

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The primary advantage of the Hybrid III is its widespread use. As a standardised test object, its parts can be exchanged between different dummies and defec-

STANDARDISED REPLACEMENTS FOR A LONG LIFE tive parts can be replaced on an individual basis. As such, a dummy has more lives than any cat and stays in use over many years. Dummies nevertheless remain essentially very rudimentary, even in their more sophisticated variants. “Joints, muscles, tendons,

ligaments, bones – all the essential biological features of human beings, can only be modelled on a very basic level with dummies,” explains Daimler expert Dr Hakan Ipek. An alternative is THUMS (Total Human Model for Safety) – the model of a virtual human being (see page 23). In the light of this state of affairs, Oskar and his colleagues are likely to be put out to grass one day. They will certainly have earned their retirement – countless people owe their health and their lives to the tests carried out with the dummies’ help. ■

Calibration: As their name suggests, side impact dummies (SID) are used to measure side collisions. Their special sensors also must be calibrated, as shown here with the calibration pendulum

GETTING INTO SHAPE Preparing the dummies In order to obtain reliable test results, the dummies have to be calibrated each time before use. The head of Hybrid III is dropped from a height of 40 cm in an apparatus, for example, in order to set the instruments accordingly. The head is then bolted onto the shoulders and after brief acceleration followed by abrupt braking the flexibility of the neck is checked. The shoulders and head are then connected to the torso which has been subjected to impact from a pendulum in a test apparatus in order to check the flexibility of the thorax.

Pedestrians: Tests aimed at improving protection for pedestrians first got underway back in the 1970s

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CRASH POST-SAFE

OVERVIEW: POST-SAFE functions of the S-Class Activation of the hazard warning lamps to secure the scene, warn following traffic and protect the occupants from a secondary accident Activation of interior lighting to help passengers and emergency services at night The central locking system is unlocked for easier access by the emergency services Closed side windows are lowered to allow venting of smoke from activated airbag systems and give the occupants a clear view (orientation/avoiding panic) The electrically adjustable steering column is raised to facilitate rescue or egress by the occupants The belt buckles on the rear seats are extended and illuminated, allowing easier access to the buckle and thereby facilitating rescue or egress by the occupants Mercedes-Benz emergency call system activated to notify emergency services of the location and emergency situation and initiate rescue Automatic engine cut-off to prevent hazards and to stop the vehicle moving unintentionally High-voltage power supply switched off on hybrid vehicles to cut the voltage to the vehicle during rescue

Digital rescue card: Mercedes-Benz is equipping new models with a QR code. Using a smartphone or tablet, this allows the emergency services to access a rescue card for the specific model. This card contains all the information needed to rescue casualties quickly

Swift access to all vehicle data relevant for rescue via a QR code on the fuel filler flap and on the opposite B-pillar

MERCEDES-BENZ EMERGENCY CALL SYSTEM Help at the scene, fast

FOLLOWING AN ACCIDENT

RAPID RESCUE MERCEDES-BENZ’S SAFETY CONCEPT COMPRISES A HOST OF FUNCTIONS TO FACILITATE CASUALTY RESCUE. THE VEHICLE QR CODE IS JUST ONE. THIS GIVES THE EMERGENCY SERVICES SWIFT ACCESS TO ALL RELEVANT VEHICLE DATA. MERCEDES-BENZ ALSO PROVIDES PRACTICAL TRAINING FOR FIRE SERVICES.

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In combination with COMAND Online, the brand’s new models are equipped with the Mercedes-Benz emergency call system. If COMAND Online is connected to a mobile phone, the emergency services can be rapidly and automatically alerted in the event of a serious accident. After the airbags or the pyrotechnical belt tensioners are triggered, the vehicle’s exact GPS position and vehicle identification number (VIN) are sent by SMS to a special emergency centre, with positional data also being transmitted using the DTMF method (dual-tone multi-frequency) at the same time. On receiving the call, the emergency centre establishes voice contact with the vehicle occupants in a matter of seconds. 171

CRASH POST-SAFE

ercedes-Benz coaches the emergency services: in practical training sessions, fire services are able to learn and apply various rescue options relating to the latest models from Mercedes-Benz and smart. Under the guidance of experienced, specially trained Daimler employees, the fire services practise the correct handling of vehicles that have been involved in an accident.

Attention is paid to detailed aspects: where should spreaders or expanders be positioned? Where are the sections of bodywork located which are made of ultra-high performance steel grades to optimise passive safety, but which may make it more difficult to cut through the vehicle body? Where are the gas generators for the side airbag or windowbag? If possible, these should not be damaged during a rescue operation. Andreas Wilhelm, a member of the Baden-

Baden fire service, describes the importance of these training sessions: “Daimler offers us unparalleled practical training. It is particularly important to familiarise ourselves with handling the most modern vehicles under rescue conditions. Normally we have to conduct such exercises using old, scrap cars which are technologically outdated and enable only limited preparation for call-outs.” ■

Photo: picture alliance / dpa

Destruction for a good cause: The exercises cover the most effective places to position spreaders and expanders

Leadership: The official Formula One Safety Car is driven by Bernd Mayländer

SAFETY CAR Increased safety in Formula One When it comes to safety in motorsport, Mercedes-Benz is out in front: for the 18th year in a row, in 2013 performance brand AMG has supplied the official Formula One Safety Car and the official Formula One Medical Car. The stewards always deploy the SLS AMG GT and the C 63 AMG Estate if bad weather or unusual occurrences pose a threat to race safety. The job of these cars is to guide the Formula One field safely around the course until the hazardous situation is averted. Firefighter drill: during practical training exercises, the emergency services are able to practise how best to get into the cab of a truck which has been involved in an accident

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16.472

CRASH FACTS, FIGURES AND CURIOSITIES

KILOMETRES In the first few years, test vehicles were not guided along the track but instead just their steering was fixed. As a result, some test vehicles missed the barrier or corkscrew ramp and instead landed in the stream next to the test track. Unlike this car, which is going nowhere, the Schwippe flows for another 16.472 kilometres until it joins the Würm river.

DID YOU KNOW? 4

1979

CANS

What actually happens when an airbag is deployed? Brave engineers found out the answer to this question by taking part in many tests themselves while the passenger airbag was developed in the late 1970s. Cameras mounted on the side arms recorded what happened in minute detail.

Before the Bendix simulator was operational, in the 1960s accident researchers used a spring-loaded test sled to provide acceleration for component tests. This helped them to optimise steering systems and seat belts, for example. Large gherkin cans from the works canteen were used to create a crumple zone. Taking the cue from these cans, the inventor of the cost-saving crashboxes was nicknamed “Canned Maier”.

DEGREES

Now and again you need to know how competitor vehicles are performing, too. Here a Beetle waits to take its final journey. The hot-water rocket used for propulsion is fitted onto a single-axle trailer and consists of a pressure tank, a quick-opening valve and a rocket nozzle. To produce thrust, prior to the experiment the vessel is filled about three quarters full with water and heated until the water reaches a temperature of around 260 degrees Celsius. When the valve is opened, the resulting excess pressure propels the vehicle and rocket and accelerates the entire unit to more than 100 km/h.

TONNES

In the early years, a concrete block weighted down with old pressing tools acted as a mobile barrier for collisions. This 30-tonne, heavy monster was cleverly fixed in place by letting the air out of the tyres.

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260

2,400

YEARS

Test sleds or catapults have been used for component testing since the early 1960s. In 1972 Daimler installed a Bendix accident simulator into the new safety centre in Sindelfingen in order to test restraint systems, steering systems, seats, instrument panels and roof racks. Cameras are installed on the side arms. The catapult was invented in Greece in 400 BC (from the Ancient Greek “katapelteˉs”, “kata” meaning “downwards” plus “pallein” meaning “to hurl”).

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OUTLOOK XXXXXXXXXXX

OUTLOOK OUTL

SWARM INTELLIGENCE

THE FUTURE HAS ALREADY BEGUN:

An estimated 50 billion MIGRATORY BIRDS fly back and forth between their breeding grounds and winter quarters each year. In these flocks, each bird takes its lead from its neighbour and adopts the same speed and direction. Formation flying protects against predators and saves energy.

CAR-TO-X

COMMUNICATION PLAYS AN IMPORTANT ROLE WHEN IT COMES TO THE VISION OF ACCI-

INTELLIGENT DRIVE RESEARCH VEHICLE SHOWS THAT IN PRINCIPLE, AUTONOMOUS DRIVING IS ALREADY POSSIBLE TODAY EVEN IN INTER-CITY AND URBAN TRAFFIC. 176

Photo: Lu/Viewstock/Corbis

DENT-FREE DRIVING. AND THE MERCEDES-BENZ S 500

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OUTLOOK CAR-TO-X COMMUNICATION

CAR-TO-X COMMUNICATION

VEHICLES IN A DIALOGUE INTELLIGENT NETWORKING OF CARS WITH EACH OTHER AND WITH THE INFRASTRUCTURE CAN HELP TO PREVENT ACCIDENTS AND TAILBACKS. BEGINNING IN 2013, MERCEDES-BENZ BRINGS RADIO-BASED CAR-TO-X TECHNOLOGY ONTO THE ROADS. AS AN INITIAL STEP THE DRIVE KIT PLUS IS USED WHICH, IN COMBINATION WITH A SMARTPHONE AND THE DIGITAL DRIVESTYLE APP DEVELOPED BY MERCEDES-BENZ, TURNS THE VEHICLE INTO A SIMULTANEOUS TRANSMITTER AND RECEIVER OF INFORMATION.

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OUTLOOK CAR-TO-X COMMUNICATION

very driver has experienced potentially dangerous situations like this: accidents and tailbacks are often only reported on the radio after a delay of several minutes. This is where Car-to-Car communication can help: because vehicles networked with each other can exchange information very rapidly to warn drivers. By integrating Car-to-X communication into the Drive Kit Plus and the Digital DriveStyle App, Mercedes-Benz offers

the new technology on a universal basis in almost all Mercedes-Benz passenger cars since the end of 2013. If a vehicle is reported to have broken down in the driver’s vicinity, a warning is given and the location of the danger is marked on the map. Moreover, every vehicle equipped with Car-to-X technology can also send hazard warnings to other road users. Mercedes-Benz passenger cars are able to recognise many of these events automatically by virtue of seamless integration of the Car-to-X system into the vehicle systems. A manual reporting option has been developed for hazards that are not or not

yet detectable automatically. At the touch of a button, e.g. vehicles travelling the wrong way or shed loads can be reported to the MercedesBenz Cloud. A warning message to all vehicles fitted with Car-to-X technology which are in the vicinity is sent. As a next step Car-to-X technology will also contribute to more efficient mobility, as e.g. highly accurate traffic situation information is used to improve traffic flows by controlling traffic light systems to suit. ■

Time saving: with the use of Car-to-X technology, information about potential hazards to road traffic, e.g. a vehicle travelling the wrong way, is rapidly and precisely relayed to other road users affected

TRAFFIC LIGHT, THIS IS CAR, over and out

Drivers do their share: accidents and breakdowns can be reported manually so that other road users are warned

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Attention, emergency vehicle coming from the right: warnings like this are possible if police and emergency vehicles are equipped with Car-to-X technology

One of the world’s largest field trials recently demonstrated that Car-to-X communication is mature enough for day-to-day motoring: during the research projekt simTD (Safe Intelligent Mobility – Trial in Deutschland/ Germany) under the aegis of Daimler AG, a total of 120 cars and three motorcyles were on the roads in the Rhine-Main region between August 2012 and June 2013. All the vehicles were equipped with the same technology. All in all more than 1,650,000 kilometres were covered during this field trial – on the A5 motorway, on federal highways B3 and B455, and in the inner-city area of Frankfurt. The vehicles and infrastructure were networked with the help of so-called “ITS Roadside Stations”. The stations were in contact with the local traffic control systems, but could also receive signals from the test vehicles and send signals to them. The simTD project is a joint project between German automobile manu-

facturers, automotive suppliers, communication companies, research institutes and the public sector. Daimler is also researching and developing C2X communication in the USA. At the location in Palo Alto, California, for example, vehicles have likewise been equipped with C2X systems and put through trials. Apart from its involvement in the simTD research project and the research in the USA, Daimler’s strong commitment to C2X communication is shown by many years of participation in other projects in this field. For example, the company was the initiator of basic research projects such as NoW (Network on Wheels) and Fleetnet, whose results have been incorporated into the present C2X activities and their standardisation. Daimler is also a founding member of the CAR 2 CAR Communication Consortium (C2C CC), and is driving the Europe-wide harmonisation of this technology forward in the DRIVE C2X project.

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OUTLOOK AUTONOMOUS DRIVING

IN AUGUST 2013, WITH ITS S 500 INTELLIGENT DRIVE RESEARCH VEHICLE, MERCEDES-BENZ

AUTOPILOT

THE SELF-DRIVING CAR

BECAME THE FIRST MOTOR MANUFACTURER TO DEMONSTRATE THE FEASIBILITY OF AUTONOMOUS DRIVING ON BOTH INTERURBAN AND URBAN ROUTES. THE ROUTE IN QUESTION, COVERING THE 100 KILOMETRES OR SO FROM MANNHEIM TO PFORZHEIM, RETRACED THAT TAKEN BY BERTHA BENZ WHEN SHE BOLDLY SET OFF ON THE VERY FIRST LONG-DISTANCE DRIVE.

he main advantages of autonomous driving are plain to see: it allows motorists to reach their destination quickly, safely and in a more relaxed frame of mind. Above all on routine journeys, in traffic jams, on crowded motorways with speed restrictions and at accident blackspots, an autono-

Zebra-crossing: a major challenge in urban traffic

FASTER AND MORE RELAXED ARRIVAL mous vehicle is capable of assisting the driver and taking over tedious routine tasks. Partially automated driving is already available to drivers of new MercedesBenz E- and S-Class models: The new DISTRONIC PLUS with Steer Assist and Stop&Go Pilot is capable of steer-

Overtaking and cutting in: complex interurban traffic

FOLLOWING THE TRACES of Bertha Benz The research vehicle was equipped with a further development of near-series sensor systems. For example, the developers taught this technology platform to know where it is, what it sees and how it should respond of its own accord: with the aid of its highly automated “Route Pilot”, the vehicle was able to negotiate its own way through dense urban and rural traffic.

Hands off the wheel: in an emergency the test drivers would have been able to intervene at any time. The red button is used to stop the autopilot

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OUTLOOK AUTONOMOUS DRIVING

TRAFFIC-LIGHT RECOGNITION Green light ing the vehicle mainly autonomously through traffic jams (see page 140). The next step is highly automated driving where the driver no longer needs to monitor the vehicle continuously. In August 2013, with the S 500 INTELLIGENT DRIVE research vehicle, Mercedes-Benz demonstrated that this is already possi-

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ble today, beyond closed-off test routes and comparatively clear situations. In the heavy traffic of the 21st century the self-driving S-Class had to deal autonomously with a number of highly complex situations â&#x20AC;&#x201C; traffic lights, roundabouts, pedestrians, cyclists and trams. It should be noted that this pioneering achievement was

not realised with the use of extremely expensive, special technology, but with nearseries technology. It is already available in similar form in the new C-, E- and S-Class. The project thus marks a milestone along the way that leads from the self-propelled (automobile) to the self-driving (autonomous) vehicle. â&#x2013;

The exact positions of all traffic-lights on the test route are stored in the map material. A colour camera behind the windscreen recognises the status of the relevant traffic-light. If the traffic-light is amber or red, the vehicle brakes autonomously and only resumes its journey autonomously once the light changes to green

AUTONOMOUS AT JUNCTIONS S 500 INTELLIGENT DRIVE observes right-of-way rules

AUTONOMOUS NEGOTIATION OF ROUNDABOUTS Aware of other cars

The maps created for autonomous driving list all junctions and traffic signs in effect there. When the car approaches such a location, it uses its radar sensors and cameras to examine the surroundings. Approaching vehicles are recognised, and the right-of-way rules are obeyed as the car autonomously responds to the traffic situation

The vehicle recognises a roundabout by the map data. The surroundings are checked with the help of the radar sensors. The car stops if another car on the roundabout is approaching and there is insufficient space to join the flow. Otherwise the roundabout is crossed autonomously

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OUTLOOK INTERVIEW

RALF G. HERRTWICH

“AUTONOMOUS DRIVING IS COMING” AN INTERVIEW WITH THE HEAD OF DRIVER ASSISTANCE AND SUSPENSION SYSTEMS AT DAIMLER ADVANCE DEVELOPMENT

Many people still need to get used to the idea that cars are able to drive around autonomously. Do we actually need cars that drive autonomously? Herrtwich: This is unavoidable if we really want to make the vision of accident-free driving a reality. Systems we have already introduced in our cars

quite clearly show that autonomous braking when an impending accident is detected provides an evident safety benefit. Also, the driver is relieved of stress in situations where driving becomes tedious. The Stop&Go Pilot in the S-Class is the best example of this.

Do you find that customers accept today’s assistance systems? Or do you have to battle with scepticism? Herrtwich: At first there was scepticism, no doubt about it. And incidentally it was no different when ABS and ESP® were introduced. But as the technical performance of these assistance systems improves, driver confidence in them is gradually increasing and they

rof Ralf G. Herrtwich (51) has worked at Daimler AG Group Research since 1998. Holding a diploma in Information Technology, he began his career at the Technical University of Berlin and at UC Berkeley. This was followed by management positions with IBM and several telecommunications companies. After ten years as Head of Advance Development for Infotainment and Telematics, he is currently responsible for Driver Assistance and Suspension Systems, and in this function for future safety and comfort innovations at Mercedes-Benz. Since 2009 Herrtwich has also been an Honorary Professor for Vehicle Information Technology at the Technical University of Berlin.

are more and more interested in the subject. Driver assistance systems have now become a very important competitive factor. But we still have a long way to go, do we not, from assisting drivers in stopand-go traffic to the completely autonomous driving that you demonstrated on the Bertha-Benz route in August 2013? Herrtwich: This is a long journey which we are undertaking in stages. Our specific vision for the next step is autonomous driving on motorways, and we think this can be realised early in the next decade. In principle we already have the sensor systems for this on board, in the form of the stereo camera and radar sensors. It is now a matter of intensive trials, so that we can be sure that the signal processing also delivers the right results at higher speeds.

And what about autonomous driving off the motorway? Herrtwich: That is a far more complex matter. In this case we need much more information about the car’s surroundings. Oncoming traffic, pedestrians, cyclists and children playing; traffic lights, junctions and roundabouts, etc., can only be negotiated if the vehicle precisely knows the route it is to cover autonomously. That is also how we prepared for the Bertha Benz drive – the S-Class learned the route intensively beforehand. To give you an idea of the time perspective before cars can drive anywhere autonomously: I think this will still take a good 20 years. Of course there are legal questions to be resolved as well as technical issues. Herrtwich: Quite right. Autonomous driving is still a grey area today, as practically all traffic regulations worldwide stipulate that a driver must have control over the vehicle. One could ar-

gue that this is in fact the case with autonomous driving: at least in our vehicles, the computer can after all be switched off by the driver at any time. But without doubt this is a different form of control than we are accustomed to. In order to stay on the safe side with respect to current legislation, we measure the driver’s steering impulses when the Stop&Go Pilot is in operation – if the driver’s hands are not on the wheel, the system is switched off after a short time. Naturally we do not expect things to remain like this in the mid-term, however: legislation is always adapted in line with technical progress, and that will be the case here too. We would not be working in the field of autonomous driving if we had no solutions in mind for these and other technical and legal questions. ■

A route learned by heart: the driver did not need to intervene during the demonstration drive from Mannheim to Pforzheim

Following the trail of Bertha Benz: Ralf Herrtwich was responsible for the autonomous drive undertaken in the S 500 INTELLIGENT DRIVE

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OUTLOOK FACTS, FIGURES AND CURIOSITIES

DID YOU KNOW? 25

1968 As yet the Vienna Convention on Road Traffic of 1968 forbids driverless vehicles. Clause 5 of the Convention reads: “Every driver must have control of his vehicle at all times or be able to lead his animals”. In addition every vehicle on the road must have a driver. Experts expect the Convention to be revised fairly soon.

PERCENT

Well over 95 percent of all day-to-day journeys are on routes which a vehicle has already covered before. Like a human, a vehicle equipped with a corresponding sensor system should therefore be able to learn a route by heart. At the “driveU” innovation centre founded by Daimler and the University of Ulm in 2012, scientists are therefore also researching into how such background knowledge stored by the vehicle might be used.

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MILLION EUROS

In the Villa Ladenburg project, the Daimler and Benz Trust supports the scientific analysis of social effects arising from autonomous driving. The Trust supports scientists intensively concerned with the subject of autonomous driving to the tune of around € 1.5 million. At the end of the two-year support period, these specialists will submit a white paper with a comprehensive overview of autonomous driving.

YEARS AGO

The research project EUREKAPROMETHEUS initiated by Daimler-Benz in 1986 was an early milestone. The test vehicles made newspaper headlines in 1994, when they covered around 1,000 kilometres mainly autonomously on a multi-lane motorway in the greater Paris area, and in 1995 when they drove from Munich to Copenhagen.

1.5

300

GIGABYTES

To enable the developers to reconstruct the decisions made by the autonomous S 500 INTELLIGENT DRIVE research vehicle in individual driving situations, the car recorded all its sensor data. Images from the stereo camera alone generated 300 gigabytes of data every hour.

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TEST SUBJECTS

Just as when the automobile was originally invented, it will first be necessary to build up confidence in the technical capabilities of the systems. This is borne out by a recent study carried out by the Customer Research Centre at Mercedes-Benz involving around 100 test persons aged between 18 and 60. The initial scepticism of the study participants was almost entirely dispelled following an autonomous drive in the driving simulator. Even among those participants who were negatively disposed to begin with, there was a significant increase in acceptance after the drive in the simulator.

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TRAFFIC-LIGHTS

125 years after the first long-distance automobile journey by Bertha Benz and her sons, Mercedes-Benz developers with the S 500 INTELLIGENT DRIVE research vehicle covered the route from Mannheim to Pforzheim autonomously. There were a total of 155 traffic-lights and 18 roundabouts on the roughly 100 km route.

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RECALL HERITAGE

1900 Wilhelm Maybach develops the Mercedes 35 HP THE KEY MILESTONES

PACEMAKER FOR SAFETY MERCEDES-BENZ IS THE PIONEER OF AUTOMOBILE SAFETY. NO OTHER AUTOMOTIVE BRAND RESEARCHES AS INTENSIVELY IN THIS FIELD, AND HAS BROUGHT AS MANY KEY INNOVATIONS TO MARKET. SINCE THE INVENTION OF THE AUTOMOBILE IN 1886, MERCEDES-BENZ AND ITS BRAND PREDECESSORS HAVE MASSIVELY INFLUENCED THE DEVELOPMENT OF ACTIVE AND PASSIVE SAFETY, AND REPEATEDLY REDEFINED THE STANDARDS.

Around 50 years of passenger car safety development: from the world’s first car with a crumple zone (model 220) to the C-Class (W 204)

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as a vehicle with exemplary handling stability. Contributing features are the long wheelbase, the low centre of gravity, the engine bolted to the frame and the wide track.

1921 The Mercedes 28/95 HP gets front wheel

brakes. The other car models of DMG (Daimler Motoren Gesellschaft) and Benz & Cie. follow in 1923/24.

1931 The Mercedes-Benz 170 (W 15) is the first

series production car with a hydraulic braking system and independent suspension using swing axles at the front and rear.

1941 Patent no. 742 977 dated 23 February 1941

is granted for the platform frame developed by Béla Barényi.

1945 In this and subsequent years Béla Barényi

develops the vehicle studies “Concadoro” and

“Terracruiser”. Both studies are among the most important stepping-stones towards the safety bodyshell of cellular construction.

1949 Patent no. 827 905 dated 23 April 1949 is granted for the conical pin door lock.

1952 Patent no. 854 157 dated 28 February 1952 is

granted for the safety bodyshell with a rigid passenger cell and crumple zones. In 1959 it is employed in the Mercedes-Benz W 111 series.

1954 The W 180-series Mercedes-Benz 220a is given

a single-joint swing axle with a low pivot point.

1958 Patent no. 1 089 664 dated 2 July 1958 is

granted for the wedge-pin door lock. In 1959 it is introduced as standard in the “Fintail” (W 111) models.

1959 Systematic accident research using crash tests and dummies commences.

Exemplary roadholding thanks to highly sophisticated suspension geometry: Mercedes 35 HP from 1900

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RECALL HERITAGE

1959 The Mercedes-Benz W 111 series (“Fintail”)

is the first to feature a safety bodyshell, an interior designed to prevent secondary injuries and wedge-pin door locks.

1961 Disc brakes and dual-circuit braking systems are gradually introduced into the passenger car range.

1966 Hans Scherenberg and Béla Barényi formulate

the distinction between active and passive safety that remains valid until the introduction of PRE-SAFE®.

1967 The safety steering system with a telescopic steering column and impact absorber is introduced into the entire Mercedes-Benz passenger car range.

1971 An extensive package of active and passive

safety features has its debut in the 107-series Mercedes-Benz SL: collision-protected fuel tank above the rear axle, heavily padded dashboard, deformable or recessed switches and controls,

four-spoke safety steering wheel with an impact-absorbing boss and a wide bolster plate, newly developed air deflectors on the A-pillars and large rear lights with a ribbed surface profile to substantially prevent soiling.

1976 The “Safety steering shaft for automobiles”

patented by Béla Barényi in 1963, with a steering column in the form of a corrugated tube, has its debut in the Mercedes-Benz W 123 series.

1978 The second-generation anti-lock braking system ABS celebrates its debut in the W 116-series S-Class. Mercedes-Benz had already presented a first version not yet up to series production maturity in 1970. From 1980 ABS is standard equipment in all model series.

1979 The W 126-series Mercedes-Benz S-Class

is the first car constructed to cope with an asymmetrical frontal collision employing a forked front member structure.

1981 The world’s first driver airbag is introduced

in the S-Class. Mercedes-Benz has conducted research into this supplementary restraint system since 1968. From 1982 the driver airbag becomes available for all models, followed by the front passenger airbag in 1987 and the sidebag in 1995.

1982 The multi-link independent rear suspension is

introduced in the Mercedes-Benz 190 (W 201).

1989 The new SL Roadster (R 129) sees the debut

for a seat-integrated belt system and a rollover bar that automatically extends when a rollover threatens.

1995 Rain sensor and xenon headlamps are intro-

duced in the 210-series Mercedes-Benz E-Class.

1995 The Electronic Stability Programme ESP

1997 The sandwich floor of the W 168-series

A-Class allows the engine to slide beneath the passenger cell during a frontal collision.

1998 The windowbag has its premiere as an optional extra for the Mercedes-Benz S-Class.

1999 The proximity control system DISTRONIC has its debut.

1999 The active suspension system ABC (Active

Body Control) enters series production in the C 215-series CL-Class.

1999 Bi-xenon headlamps become standard equipment in the 215-series CL-Class.

2001 Head-thorax sidebags are introduced in the SL-Class Roadsters from Mercedes-Benz.

is introduced as standard in the 140-series S-Class Coupé.

1996 Mercedes-Benz introduces Brake Assist BAS

2002 The preventive occupant protection system

PRE-SAFE® is introduced in the Mercedes-Benz S-Class, gradually followed by the other model series.

into series production as a world first.

First trials of the airbag: the development of the airbag by Mercedes-Benz began as early as 1968. Pictured here is a crash test in 1969

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Shorter braking distance, improved directional stability: ABS tests in the 1970s with an S-Class (W 116)

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RECALL HERITAGE

2003 The active light function with bi-xenon headlamps is introduced (211-series E-Class).

2005 The integral safety concept of Mercedes-Benz combines the different active and passive safety systems.

2005 Mercedes-Benz presents various safety systems in the 221-series S-Class, for example DISTRONIC PLUS, Brake Assist BAS PLUS and Night View Assist.

2006 The Intelligent Light System ensures

optimum light distribution on the road surface, depending on the driving situation (in the 211-series E-Class).

2006 PRE-SAFE Brake celebrates its premiere as ®

an optional extra for the 216-series CL-Class.

2007 Blind Spot Assist has its debut as an optional extra in the S-Class and CL-Class.

2009 The drowsiness detection system

ATTENTION ASSIST has its debut in the 212-series Mercedes-Benz E-Class.

face-lifted 221-series Mercedes-Benz S-Class. In addition Torque Vectoring Brake enters series production.

2010 World premiere of Active Blind Spot and

Active Lane Keeping Assist in the CL-Class (C 216) and S-Class (W 221).

2011 The radar-based assistance system

COLLISION PREVENTION ASSIST is introduced as standard in the B-Class.

2013 New assistance systems with considerably

extended functions (DISTRONIC PLUS with Steering Assist and Stop&Go Pilot, Brake Assist BAS PLUS with Cross-Traffic Assist, Active Lane Keeping Assist, Adaptive Highbeam Assist Plus, Night View Assist Plus, ATTENTION ASSIST) are introduced in the S-Class. New PRE-SAFE® functions (PRE-SAFE® Brake, PRE-SAFE® PLUS, PRE-SAFE® Impulse), improve protection in the rear (belt buckle extender with PRE-SAFE®, beltbag).

2013 Mercedes-Benz brings Car-to-X communication onto the roads.

2009 Crosswind Assist has its debut as an additional 2014 The QR code sticker allowing the emergency function of Active Body Control (ABC) in the

services direct access to the vehicle-specific rescue card also becomes available for retrofitting in older Mercedes-Benz models. ■

IMPRINT

Publisher Daimler AG Global Communications Mercedes-Benz Cars D-70546 Stuttgart www.media.daimler.com Concept and Realisation die Presse-Partner GmbH Alexandra Knaupp, Jochen Kruse D-69488 Birkenau Design PW.GRAFIK Peter Wurz D-72669 Unterensingen Editorial support Jochen Haab, Dr. Hakan Ipek, Dirk Liefeith (all Mercedes-Benz Technology Center, Sindelfingen), Norbert Giesen, Jens Schäfer, Stefan Schuster, Ralf Stadelmaier Photography If not noted otherwise at the picture: Markus Bolsinger and Daimler Archives Printer C. Maurer Druck und Verlag GmbH & Co. KG D-73312 Geislingen

COLLISION PREVENTION ASSIST as standard in the compact class: Mercedes-Benz B-Class (2011)

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