GROWN HOME

The Kenworth K220 supersedes the K200 which has been around for more than 12 years. This new model takes some big steps to achieve the next level in the evolution in PACCAR’s cabover. The K220 model commenced production in April 2023 and is expected to remain Kenworth’s cabover offering until at least the end of the current decade.

The most significant exterior change is the cab’s roof design which improves aerodynamic efficiency by a claimed four per cent. In most circumstances, where average speeds are high enough to benefit from a more slippery shape, that will translate to a fuel efficiency improvement of around two per cent. The vista windows of the K200 have been deleted for the K220 which contributes to improved sleeper cab insulation and a more easily maintained cabin temperature by the new climatecontrolled HVAC system which is similar to the one developed for the Kenworth T610. The lower positioning of the dash vents delivers an ideal amount of temperature-controlled airflow into the cab without blowing it directly into the driver’s face. The weather is reasonably mild for this trip from Melbourne to Adelaide and we don’t get to experience the HVAC’s performance under extreme conditions, so we just set the dial at 22 degrees and enjoy the comfort.

The K220 is available in 1.7m day cab, a 2.3m aerodynamic roof sleeper, a 2.3m flat roof sleeper and 2.8m aerodynamic roof sleeper versions. Our truck for this trip is the 2.3m aerodyne and we have hooked to a B-double set of Collins Adelaide’s refrigerated trailers loaded with chilled and frozen goods destined for Woolworth’s South Australian stores, with the combination grossing just over 58 tonnes. Since their launch in 1971, the Kenworth K-Series have traditionally been considered “drivers’ trucks” and this heritage still carries over into the K220. The ISRI air suspended seat has increased fore and aft adjustments and the pedals are relocated to a more forward position to provide additional leg room.

An essential element of the K220’s engineering brief was the integration of the multiplex electrical architecture which is essential for the communications of the sophisticated electronic systems required to support safety features such as Autonomous Emergency Braking which is a key function of the Bendix Fusion system. Autonomous Emergency Braking is available as an option until 2025 when it will become a standard feature as per Federal legislation.

The K220 provided for this test exercise is a pre-production unit and is fresh from having its Bendix Fusion system electronics upgraded and recalibrated to the latest Version 2.9 and has an extensive list of safety acronyms such as ABS, ESP, EBS and lane departure warning. The Active Cruise Control not only makes driving easier but adds another level of confidence when sharing the highway with other traffic; and is capable of bringing the truck to a complete standstill in an emergency situation by using the engine and service brakes without any input from the driver. The new 8-inch Audio Visual Navigation (AVN) unit provides an easy access display with intuitive controls for truck navigation, the audio system, and smartphone mirroring. The AVN can be integrated with up to six external cameras giving drivers full visibility of what is happening around the truck. To further help drivers remain focused on the road, the AVN is integrated with the steering wheel controls and the driver’s phone can be stored safely on either the induction charging pad, or in one of the convenient storage pockets in the new dash. Kenworth has long employed good quality switch gear and in the K220 the various toggle switches are arrayed in a logical sequence from the factory, but thanks to the multiplex wiring their functions can be quickly customised as each switch has its own

IP address and retains its function even when relocated to another socket on the dash. Much of the interior is in common with the wide conventional T610 model which is destined to receive the K220’s digital dash. The main instrument panel is a 15-inch high-definition electronic screen, with analogue gauges for air pressure and driveline temperatures located on a panel positioned to the left of the driver which manages to maintain a level of heritage appearance in combination with the latest high-tech approach to delivering information. The main instrument panel displays early intervention warnings for the driver. At the start of each shift the K220 will perform a comprehensive Systems Check and with it also provide an end of shift detailed trip and vehicle summary including statistics such as average fuel economy, idle time, and cruise control usage as well as any potential mechanical issues. The K220 essentially monitors itself and can deliver immediate warnings should anything amiss be detected.

The screen can be configured to deliver a variety of displays ranging from rudimentary speedo and tacho images to quite intensely detailed informational readouts. There is also a function which provides coaching advice to the driver to maximise performance and efficiency. The digital display is able to be customised and is readily controlled by buttons on the new generation SmartWheel which, with its attendant stalk controls, provides fingertip control of an expanded range of vehicle functions and settings. The K220 comes with the propriety PACCAR Connect telematics system which manages driver and truck performance as well as its global location in order to get the best results.

Other controls include the “duckbill” trailer brake lever that we utilise to perform the essential tug test prior to pulling out of the Collins depot in Melbourne. This electronic control can also be used in place of the hill start assistance which can be turned off if desired.

The long taper leaf front springs, in combination with the Airglide rear suspension, produce a smooth ride even on the very rough sections of the highway as we approach the SA border. A cab suspension system is currently being developed which will offer even further improved ride characteristics. Motive power comes courtesy of a Euro VI Cummins X15 rated at 565hp and providing 1850 lb/ft of torque. This ‘performance’ version of the red 15-litre engine has long legs and the interaction between the engine and the Endurant transmission is impressive. Backing up the Cummins is Eaton’s latest Endurant XD Pro 18-speed automated transmission which is 100kgs lighter than the Eaton UltraShift it replaces and has the advantage of being designed as an AMT from its conception rather than an enhanced manual-based gearbox. The engine/transmission interaction is seamless due to the sophisticated integration of those major components with input from various sensors fitted to the truck.

As we approach the end of this trip, we still have to negotiate the almost infamous Adelaide Hills descent, which is reputedly the longest and steepest main highway descent in the country and includes the Heysen tunnels. Being very conservative, we switch to manual mode by touching the button on the end of the right hand side wand and toggle down to 10th gear. As we begin the descent, we are able to hold speed at 28-35 km/h by simply swapping between the first and second stage of the Jacobs brake. We could have done it in a higher gear and maintained a speed closer to the 60 km/h truck limit, but discretion is the best part of valour. At no point did we consider it necessary to apply the third stage of the Jake or even consider touching the brake pedal. The third stage is activated by pulling the wand back against its spring detent which triggers a transmission downshift to deliver even more compression braking, but without the risk of over-revving the engine. If necessary the retardation could have been further increased by manually flicking on the engine fan. At the conclusion of the downhill journey the engine temperature is just above 80 degrees with no heat soak affecting the refrigeration unit on the front trailer as might be the case from a transmission retarder.

The K220 is a uniquely Australian product and reflects the engineering and manufacturing abilities available in this country.