GM: Aerodynamic design increases Volt's range

James B. Treece
Automotive News
August 14, 2008 - 11:37 am ET
UPDATED: 8/14/08 4:25 p.m. EDT



TRAVERSE CITY, Mich. -- The design team for General Motors' Volt plug-in hybrid car has added six to seven miles to the car's electricity-only range by improving the car's aerodynamics.

"Air does not like to go around sharp corners. It creates turbulence and drag," Bob Boniface, GM's director of design for the Chevrolet Volt and E-Flex studio, said today at the Management Briefing Seminars.

Boniface therefore made numerous changes to the original concept's design. The changes were conceived in order to support the Volt's goal of having a 40 mile range purely from the car's electric charge. More than 70 percent of U.S. commutes are less than 40 miles, GM says.

Boniface explained a number of those changes.

The concept originally had a blunt front end with a sharp crease on the corner. The production version now has a very rounded look.

The production car's grill texture is largely sealed up. The design now sends the air down the side of the car and not through the engine compartment.

A curving crease down the back corner of the concept has been smoothed. Both there and on the spoiler, Boniface said, "You want an aerodynamic 'trip' device so air leaves the car very quickly and cleanly." For the spoiler, GM added a 5 millimeter 'trip' device, he said.

The concept's sideview mirror started with a patch mount, where the structure holding the mirror sticks out horizontally from the door. For the production version, that was changed to a post mount. The mirror now sits on a post lifting from the vehicle's side.

The changes to the mirror and spoiler each cut drag by 5 counts, he said. "Why should you care, when you probably don't even know what a drag count is," he added.

For every 10 drag-counts reduction by the aerodynamic design, the design team added 0.55 miles of highway range on the vehicle's electric charge. In total, the team cut the concept's drag counts by 120, thereby adding six to seven miles to the car's range on the charge.

Those efforts are helping GM reach its target range of 40 miles on the electric charge for the Volt.

I'm impressed by the Volt. We're going to be in the market for our next car in 2011 or 2012 and so far the volt is the leading candidate....course, we'll see how they are once they actually hit the streets. I haven't owned a GM since the 70s, but I'm getting ready to head home to the General.

If they can price it at less than $40000 within a couple years after launch, it'll be a very successful car. Even if you have to pay $5k more than a comparable conventional car, the savings in gas would make up for that in 2-3 years. After that, you are saving money. And having maximum torque from 0 rpm up until around 7000rpm doesn't hurt either.

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Middle TN Z Club sponsored by Crawford Z Car Service

And what about the $5000.00 in batteries you'll be paying for with-in 5 years?

Aruba, have you checked out how long batteries are lasting in the existing electrics? Longer than 5 years on average.

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I'm concerned with all the rampant sex and nudity on TV but all I can do is sit at home shaking my fist.

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And what about the $5000.00 in batteries you'll be paying for with-in 5 years?

A customer just bought a complete set of replacement batteries for his Honda Insight for less then $1,000.

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John Coffey
[www.betamotorsports.com]

The Insight is using Nickel-Metal Hydride batteries. The Volt and other next-gen hybrids will be using Lithium Ion batteries, at a much higher cost. But they will likely last much longer than 5 years.

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-- I've had a few Zs --

NiMH batteries are quite expensive these days due to the price of nickel. Li batteries of equivalent capacity should be cheaper. The battery monitoring required may cost more, though. Net overall cost should be comparable, with the nod possibly going to Li.

40 miles is still not practical

It's 40 miles on 100% electricity and then the gas powered generator kicks on and you'll go another 500 or so miles at 50 mpg. How is that not practical?

I thought it was a diesel powered generator?

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I thought it was a diesel powered generator?

I know it runs on gas but also other various fuels. I'm not sure it would be possible for diesel to be one of those other fuels though.