engineering
noise management solutions
SAFETY – INVOLVEMENT - ENVIRONMENT Hybrid and electric vehicles present a safety concern at low speed as they often cannot be heard and recognised, particularly by high risk groups such as the elderly, children, cyclists and particularly the blind and their guide dogs. Several countries are currently reviewing legislation to state that these vehicles must emit a recognisable sound above a minimum noise level to help improve pedestrian safety. HALOsonic’s External Sound Synthesis (ESS) for electric and hybrid vehicles generates an externally recognisable vehicle sound focused in the direction of travel, which is a potentially life-saving technology. The driving experience in any car is greatly enhanced when the engine sound provides the driver with audible feedback relaying rate of acceleration and speed. This sense of involvement is lost in hybrid and electric vehicles as under battery power there is no recognisable “engine” sound. HALOsonic’s Internal Sound Synthesis (ISS) creates a link to the sensory connection that traditional internal combustion engine (ICE) cars provide, enhancing the driving experience and awareness by creating speed and throttle dependent sounds audible through the in-car entertainment system. The energy conscious car of tomorrow will be lighter and will increasingly feature new powertrain technologies, such as hybrids, cylinder de-activation, stop/start etc, many of which degrade cabin sound quality. HALOsonic’s Engine Order Cancellation (EOC) and Road Noise Cancellation (RNC) solves this problem by acoustically cancelling the unwanted sound with opposing frequencies, creating a quiet zone for each occupant without the additional weight of NVH materials.
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KEY FEATURES OF HALOSONIC
BENEFITS OF HALOSONIC
Lotus Engineering has over twenty years experience in active noise control and has patents covering four key technologies.
Active noise control technologies provide a range of benefits to pedestrians, the driver and the environment.
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Road Noise Cancellation (RNC)
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Engine Order Cancellation (EOC)
HALOsonic actively monitors and controls refinement levels in the cabin, minimising undesirable noises
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Internal Sound Synthesis (ISS)
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External Sound Synthesis (ESS)
HALOsonic improves pedestrian safety in electric and hybrid vehicles
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HALOsonic provides NVH solutions without the added weight of traditional techniques
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HALOsonic enhances the driving experience and feedback for Hybrid and electric vehicles
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HALOsonic ISS and ESS can be customised to provide a unique vehicle sound supporting the “Brand DNA”
IS-3/04-12
harman.com lotuscars.com/engineering
engineering
Throttle position sensor Accelerometers Engine speed signal Control module/amplifier Error microphones Audio system External speaker system
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SOUND SYNTHESIS (ISS and ESS)
Engine Order Cancellation (EOC)
Road Noise Cancellation (RNC)
ISS provides ‘soundscaping’ in the cabin, allowing the driver to select their favourite internal combustion engine sound. This sound can be independent from the exterior noise levels, hence avoiding maximum drive by legislation requirements.
The noise produced by combustion engines and exhaust systems is substantial. Traditional methods for reducing the transfer of this noise to the cabin have involved using large amounts of NVH material.
Multi link suspensions create multiple noise paths into the cabin. Suspension bush isolation is being reduced to improve vehicle dynamics leading to high levels of low frequency road noise, which is further increased by the trend for wider, low profile tyres.
The system delivers audible feedback to drivers even when the engine is almost silent. ESS utilises an external speaker system to apply a specified electronic sound to improve pedestrian safety. A synthetic engine ‘idle’ sound is also produced when the vehicle is switched on and the handbrake is released.
HALOsonic EOC technology uses microphones in the cabin which identify the frequencies of noise created. These are relayed to the processor which generates cancelling frequencies played back through the audio system, reducing the noise heard by the occupants without requiring the addition of NVH materials, reducing both weight and emissions.
RNC uses a series of accelerometers on the chassis to identify the frequencies of noise created; these are relayed back to a processor which generates a broadband frequency cancelling output through the vehicles audio system. Adaptive feedback control from microphones in the cabin further enhances system performance.
ISS and ESS can be embedded within a HARMAN audio system or integrated within the existing vehicle entertainment system. ESS requires only an additional speaker at the front of the vehicles and an optional speaker at the rear for improved reversing warning. RNC and EOC can be integrated into the vehicles existing audio system, requiring only the addition of between four and eight microphones for EOC and four to eight accelerometers for RNC strategically positioned close to the suspension.
LIGHTWEIGHT ARCHITECTURES - EFFICIENT PERFORMANCE - ELECTRICAL AND ELECTRONIC INTEGRATION - DRIVING DYNAMICS
United Kingdom
USA
China
HARMAN
Potash Lane Hethel, Norwich NR14 8EZ
1254 N. Main Street Ann Arbor MI 48104
7th Floor, New Jinqiao Tower No.28 New Jinqiao Road, Pudong, Shanghai. PR CHINA 201206
Becker-Goering-Str. 16 76307 Karlsbad Germany
Phone: +44 (0)1953 608423 eng-uk@lotuscars.com
Phone: +1 734 995 2544 eng-usa@lotuscars.com
Phone: + 86 (21)5030 9990 eng-china@lotuscars.com
Phone: +49 7248 71 1272 Nicole.Mehr@harman.com