GM Tweaks Production-Model Chevy Volt to Improve Aerodynamics
By Derek Stark WardsAuto.com, Aug 14, 2008 4:07 PM

TRAVERSE CITY, MI − General Motors Corp.’s Chevrolet division says it was successful in making the production version of the Volt extended-range concept car more aerodynamic in order to give consumers a longer driving range.

GM has set the Volt’s production timetable at late-2010 and the auto maker reportedly will finish the exterior design by mid-September. It also intends to field about 50 prototypes with production parts by the end of this year.

Bob Boniface, director of design, Chevrolet Volt and E-Flex Studio, unveils new details and photos of the production Volt at the Management Briefing Seminars here and says some of the major differences between the concept version and the one consumers will be able to buy include a sealed-up grille; an infotainment area in the center console with touch-sensitive screens; and a more rounded front end.

Boniface says the concept Volt’s front end has a very sharp crease. “And if you know anything about aerodynamics, air doesn’t like to go around sharp corners. It separates or becomes detached and creates turbulence. And turbulence creates drag.

“With the production Volt, you’ll notice the front corner is very rounded, and it sends the air down the side of the car.”

Production Chevrolet Volt’s rounded look contrasts with concept’s sharp lines.

Engineers also made changes to the production Volt’s side-view mirrors.

“Just by making this small change, we were able to reduce aerodynamic drag by five counts,” Boniface says.

Likewise, designers tweaked the production Volt’s spoiler, reducing drag by another five counts.

From concept to production vehicle, the auto maker has “taken over 120 counts of drag out,” Boniface says. “That’s six to seven miles (10-11 km) of extra driving range to the customer.

“Ten counts of aerodynamic drag reduction is equivalent to extending the vehicle’s range by over five-tenths of a mile (0.80 km),” he adds. “Just by tuning that mirror and tuning that spoiler, I was able to give the customer an extra half-mile of driving range.”

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The production Volt remains capable of traveling 40 miles (64 km) on pure electricity, Boniface says, and will have a small gasoline engine on board to recharge the battery if drivers go beyond that range. He notes more than 75% of all daily commutes in the U.S. are less than 40 miles.

“In early 2007, we decided to pursue the Volt concept as a production vehicle, and there were a lot of things to consider,” Boniface says.

A few of those included speed to market, validation of components and the necessity of the Volt as global vehicle.

“Each of these elements created turbulence of its own, and we had to design the vehicle from the inside out,” Boniface says. “The Volt is an important vehicle, not just for GM, but for the industry as a whole.”

dstark@wardsauto.com