The absence of noise associated with electric vehicles is considered a relief for many traffic participants. But at the same time, cars gliding along in almost perfect silence represent a potential source of danger. Audi, like many other OEMs, now is trying to find the ideal sound for the e-cars.
It sounds like a paradox: One of the most striking features of e-cars, the absence of the robust sound generated by the exhaust pipe of a six-cylinder sports car or the knocking of a diesel engine creates a potential hazard for pedestrians. E-cars driving at speeds up to 25 km/h are typically not generating any noise at all, only at higher speeds the tyre noise is increasing, and at highway speed, in terms of noise there is no significant difference between electrical vehicles and conventional ones.
The absence of noise creates headaches to traffic safety experts. Used to the acoustic warning generated by conventional vehicles, pedestrians could fail to perceive the approach of electric cars and thus inadvertently cross the way of the e-car with imaginable consequences, they warn. Associations for the Blind all over the world already have demanded to give e-cars their own specific sound in order to warn visually impaired or blind persons. In the USA and Japan, legislative activities are already under way.
Like other OEMs, Audi engineers are alarmed by this potential hazard. The company has set up a research program to determine the best sound for its future e-cars. "As long as an electric vehicle drives in the speed range between 0 and 25 km/h we talk about 'quiet cars'", explained Ralf Kunkel who oversees the acoustic vehicle design for Audi. The engineers will equip future e-cars with some kind electronic sound generator. The problem for the acoustic designers is how an e-car should sound.
The challenge for the OEMs is not only to generate just a kind of noise that signals that a car is approaching: Audi engineer Kunkel regards the task of assigning a specific sound to the e-cars as a chance to create an acoustic brand label. "Of course it is natural to follow the model of the familiar combustion engine," explains Christian Schueler, head of brand development and Corporate Identity at Audi. "On the other hand, we intend to highlight the perception that electric or hybrid electric vehicles are innovative products and we want to make our brand audible also in the age of electromobility."
Now the engineers are mulling their options. Sounds similar to spaceships in science-fiction movies have been considered but have already fallen through, Audi admits. While currently no concrete solution is taking shape, the engineers already know that the electric Audi has to sound "innovatively". An idea could be the sound associated to the Audi RSQ in the movie "I, Robot", EE Times Europe Automotive learned.