Acoustic Vehicle Alerting System (AVAS) for Electric Cars

Reproducing realistic engine sounds in real time

  • Automotive CAN bus
  • Automotive Ethernet
  • C
  • CAD models
Solution

Acoustic vehicle alerting system

Industry

Automotive

Engagement model

T&M (time and materials)

Methodology Scrum
Team
  • Hardware Developers
  • Firmware Developer
  • Project Manager
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Customer

Case Highlights

Softeq provided the following services: electronics design, enclosure design, firmware development, as well as debugging and testing

  • Engine sound simulation in sync with engine operation
  • Automotive ISO 26262 ASIL-D hardware
  • Audio playback in three vehicle zones
  • Sound transmission from internal memory or external sources
  • Suitable for both cars and trucks
  • Waterproof IP67 enclosure

Problem

Vehicles operating in all-electric mode produce less noise than those with traditional combustion engines. This can be dangerous for pedestrians as they may not hear cars approaching, idling nearby, or driving off. To remedy this issue, EU Regulation No. 2017/1576 obligates all manufacturers to equip their electric vehicles with an Acoustic Vehicle Alerting System (AVAS). 

The client addressed Softeq to help them develop an AVAS device that imitates engine noises.

Solution

AVAS Device Composition

The device consists of a small control unit, flash memory, and CAN / Automotive Ethernet transceivers.

The solution is capable of reproducing realistic engine sounds in real time as the car moves, accelerates, decelerates, starts, and stops. The system supports audio playback in three vehicle zones through external loudspeakers. Compliant to the ISO 7637-2 standard, the device has a wide 7 V to 32 V operating input voltage range along with a surge protection scheme, and is therefore suitable for both cars and trucks.

Device Control and Audio Playback

Controlled via the CAN interface, the device features two sound transmission options.

The device is controlled via the CAN interface. Supported commands:

  • Waking up from sleep mode
  • Start playing the required sound
  • Stop playing the sound
  • Transmission of service information

Depending on speed, driving direction, acceleration, braking load, etc., the suitable sound will be transmitted from the multimedia unit via Automotive Ethernet or loaded from the internal memory.

To ensure that the sound will be played in sync with engine operation, we provided the solution with the possibility of mixing and cycling audio as well as playing sounds with a delay.

Results

Acoustic Warning System for Pedestrians

Softeq has completed the development of the device. The resulting solution is a flexible system that plays sounds from internal memory or external sources. The device will be integrated in the customer’s vehicle to enhance security on the road.


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