Electric cars or hybrid cars running on fully electric mode can pose a risk to pedestrians as there could be some people, especially those with hearing impairments or the blind, who are not aware of an approaching vehicle because they are just so silent. In fact, there was a bill in the US recently to require a minimum level of sound for vehicles sold in the US.
As an engineering consulting company and component designer/supplier, Lotus is tackling this issue with its new “Safe and Sound” Hybrid demo car. Lotus used a Toyota Prius as a demonstrator vehicle and applied its new Sound Synthesis system to it. The new technology combines Active Road Noise Cancellation, Engine Order Cancellation and Sound Synthesis.
A road speed signal is obtained from the vehicle and a waterproof speaker is positioned near the radiator to emit a realistic sound based on the throttle and speed of the car, projected towards the front of the car. The sound was designed to be instantly recognisable by the human brain, allowing it taking into account pitch and frequency and process it to enable us to identify vehicle speed and distance. The synthesized sound automatically stops if the hybrid car’s combustion engine kicks in.
The sound can be configured to sound like various types of engines. For example, you could drive a fully electric Tesla Roadster and enjoy the lovely rumbling sound of a flat-6 or a V8. Look after the jump for a video of the new technology.