Monday 16 December 2019

'Contrary to what some people may expect, electric vehicles are not inherently silent... and that brings its own challenges'

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Stock photo: Getty
Stock photo: Getty
Eddie Cunningham

Eddie Cunningham

We hear about so many of the challenges facing us in the electric era that I, for one, often suffer from glazed-over eyes.

But one aspect I think is fascinating has been raised by World Car Awards president and colleague Gerry Malloy.

Here's a much-shortened version of what he recently had to say (let me know what you think): "…contrary to what some people may expect, electric vehicles (EVs) are not inherently silent.

"Replacing an internal combustion engine (ICE) with one or more electric motors does not so much eliminate overall vehicle noise as change it. Yes, the engine noise we've come to expect from ICE-powered automobiles is absent, but in that absence new sound sources arise that need to be addressed.

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"Electric motors themselves create their own noise, particularly at high frequencies, and electronic controllers emit their own sounds.

"In addition, eliminating typical combustion engine noise at lower frequencies can make other sounds, such as tyre and aerodynamic noise and that from air conditioning and other ancillary systems, even more apparent.

"It's a different set of challenges. There are thermal challenges as well. Not only is there potential for localised component overheating but, without the waste heat from an engine to use, the passenger cabin of an electric vehicle can be significantly more difficult to keep warm and comfortable than that of a vehicle powered by a combustion engine.

"Some other challenges aren't different from those of ICE-powered vehicles but are important for other reasons. Challenges such as weight, for example - both overall vehicle weight and that of its individual components.

"Reducing weight has long been a goal in vehicles powered by combustion engines to aid in decreasing fuel consumption and emissions.

"In electric vehicles, reduced weight still pays dividends in terms of lower energy consumption and thus increased driving range with a given battery.

"But there's a further multiplier effect.

"The heavier the vehicle, the more battery capacity it needs to achieve established range and performance goals.

"But batteries are heavy, compared with other vehicle components, so adding battery capacity tends to increase vehicle weight disproportionately.

"It's a vicious circle that means weight reduction is just as important in an EV as in an ICE vehicle - perhaps more so.

"Added to those challenges is that of environmental responsibility for a vehicle and its components throughout its life cycle, from manufacture to disposal.

"It's a tall order."

It should be pointed out that Mr Malloy's comments were made against the backdrop of long-time World Car Awards partner Autoneum's expertise in reducing noise throughout a car.

It claims its 'ultra-silent' textile material acts as an insulator to help lower sound that enters the passenger cabin as well as pass-by noise.

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