According to research conducted by Renault, potential EV buyers have certain expectations for electric cars.  Specifically, when questioned about noise survey respondents stated that they expect, "silence, peace of mind and comfortable riding, a windy sound quality, a fluid driving experience like a skipper enjoying a sailboat."  It may seem like a valid and reasonable goal to make EVs operate as silently as possible, but a problem lies ahead.

When you eliminate engine noise and exhaust noise from a vehicle, all of the other noises become ever more apparent.  From relays within a vehicle, to electrical buzzing, to wind noise, and suspension creaks, these noises could become irritating with the lack of engine and exhaust noise to drown out the sound.

Additionally, noise emitted from the electric powertrain could be difficult to subdue.  Noises emanating from the battery cooling system, electric drive motors, and other electrical components can not be hidden with engine strain or exhaust drone.

How do you solve the potential problem?  There are two methods under consideration.  Method number one is to add an artificial exhaust or engine tone.  Some believe that this will detract from the silent driving experience.  The other method requires extensive use of sound deadening material and a constant focus or quelling noises.  This approach is costly and complicated, but may just be what the consumers want.

Which approach is taken will likely be dependent on the manufacturer.  Whereas one method is cheap and easy but produces a non-silent EV, the other method is complex and costly yet maintains the silence that many expect of EVs.

Source:  Wards Auto (login required)