TO THE EDITOR:
"Tenneco's goal: Let those EVs rumble!" (Aug. 6) is misleading about the differences between electric vehicles and electrified vehicles, which include EVs, plug-in hybrids and hybrids.
The 2020 requirement is for a sound to be made when any electrified vehicle is traveling under 19 mph. PHEVs and hybrids are usually operating under battery power only at speeds this slow, so the internal combustion engine isn't making its normal noises to warn pedestrians and bikes that there's a car approaching a crosswalk, say.
It's not clear in the article that EVs don't have mufflers or exhaust systems or tailpipes. PHEVs and hybrids do, but a full EV does not. So the common solutions mentioned, "varying the size of the muffler, or with electronic valves that adjust back pressure," don't apply to EVs, nor would Tenneco's prototype that uses a speaker alongside the tailpipe. I'm sure these are meant to apply to PHEVs and hybrids, but the lead-in paragraph about the regulation mentions only EVs.
Thanks as always for continuing to cover emerging automotive technologies.
KRISTEN HALL-GEISLER, Founder, Carsplaining, Portland, Ore.Carsplaining is a website that seeks to help people understand advances in automotive technology.