GM defends EV status of Volt after criticism

General Motors Co GM.UL on Tuesday defended the ,upcoming Chevy Volt against criticism that details of its design released this week make it more like a traditional hybrid than the pure electric concept the automaker has been promoting for the past four years.

The Volt has been the centerpiece of GM's effort to reinvent its line-up since it was announced in 2007.

The controversy over its billing comes at a crucial time for the top U.S. automaker as it readies to begin selling the Volt next month and to launch an IPO to reduce the U.S. government's ownership stake.

GM said it waited until now to disclose the details of how the Volt's gasoline engine interacts with its two electric motors to extend the car's range because it did not want rivals to copy its technology.

The debate about whether the Volt should be classified as an all-electric vehicle has little practical significance for most consumers. The highly anticipated vehicle will be produced in limited numbers initially and a waiting list of green car enthusiasts almost guarantees that the Volt will be sold out.

GM expects to begin limited sales of the Volt in November and has offered it for test drives to the media in the past week along with a briefing on the details of its engineering.

Some auto critics suggested the Volt had more in common with the hybrid Toyota Motor Corp (7203.T) Prius than GM had let on. The "Inside Line" on Edmunds.com bannered a headline, "GM lied: Chevy Volt is not a true EV."

But GM product chief Tom Stephens defended the automaker's description of the Volt as an extended-range electric car, a distinction that sets it apart from the market-leading Prius.

"I think we have from day one been extremely accurate in the way we describe the vehicle," Stephens told reporters.

GM: KEY PATENT GRANTED IN SEPTEMBER

Stephens said GM just received a patent in September on key technology covering the interaction of the gasoline engine with its electric drive system.

The automaker says the Volt's range in electric mode is 25 miles to 50 miles, with the low end possible under very cold or hot conditions.

When the Volt's 400-pound battery is depleted, the 1.4 liter gasoline engine provides power to help drive the wheels at highway speeds, GM said.

But the engine cannot propel the car without engaging the electric motors, Stephens said.

GM expects the U.S. Environmental Protection Agency to provide a fuel efficiency rating soon for the Volt.

Stephens said those ratings would likely include a range under fully-electric driving conditions, a miles-per-gallon when the vehicle's battery is depleted and estimates for its mileage under a range of charging scenarios.

Coming out of bankruptcy in August 2009, GM had touted an efficiency rating of up to 230 miles per gallon for the Volt using a provisional testing method supplied by regulators.

The Volt has been priced at $41,000 before federal and state tax incentives. It is expected to compete with the Nissan Motor Co (7201.T) Leaf and the Ford Motor Co (F.N) battery-powered Focus to be introduced in late 2011 as well as a rechargeable version of the Prius due in 2012.

GM said on Tuesday the automaker and Michigan utilities DTE Energy (DTE.N) and Consumers Energy have pledged to install more than 5,300 charging stations in the state to speed the adoption of the Volt.

The automaker plans to have nearly 350 charging stations for employees at its Michigan facilities and more than 1,500 Chevrolet dealers who will sell or service the Volt, GM said.

Another 4,400 electric-car charging stations for consumers will be made available through a program funded by the U.S. Department of Energy.