Acoustic Vehicle Alerting System (AVAS) for Electric Cars

Reproducing realistic engine sounds in real time

An electric car manufacturer wanted to develop an AVAS device for electric vehicles. According to obligatory regulations, the solution had to simulate engine noises.

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

Electric vehicles produce less noise than those with traditional combustion engines. This can be dangerous for pedestrians as they may not hear cars approaching. To remedy this issue, EU Regulation No. 2017/1576 obligates all manufacturers to equip their electric vehicles with AVAS.

The client asked Softeq to help them develop an AVAS device that imitates engine noises. The scope of work spanned electronics design, enclosure design, and firmware development. We were also tasked with testing and debugging the solution.

Solution

Acoustic-Vehicle-Alerting-System-(AVAS)-for-Electric-Cars

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.

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Result

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.