WASHINGTON – Before kicking off Job One at the Detroit-Hamtramck assembly plant in November, General Motors Co. will build more than 300 pre-production Chevrolet Volt extended-range electric vehicles for testing by engineers, consumers and media.

Currently, GM is “deep in the development stage,” testing and validating the Volt’s software, a spokesman says.

Included in that software is an algorithm ensuring the internal-combustion engine starts up every 60 days or so to prevent gasoline in the vehicle’s tank from excessive aging.

The engine would engage only when the car is being driven, not when it is parked in a garage being charged. The 4-cyl. will run for about 10 minutes in this mode, enough time to perform some diagnostic checks on the vehicle.

Trent Warnke, a GM development engineer, says the auto maker also will recommend low-mileage consumers fill their gas tanks only half way to minimize potential for spoilage.

In addition, the Volt's fuel system is pressurized, and there will be zero evaporation. “It's like shrink-wrapping your food,” Warnke says. “It keeps the fuel from aging.”

At the recent auto show here, GM rented a parking lot at RFK Stadium to provide test drives to government officials, members of Congress and the media in one of the 80 pre-production Volts the automaker virtually hand-built at its Tech Center in Warren, MI.

In a drive of nearly four miles (6.4 km), the experience is transparent – there’s no difference from piloting a conventional car or production hybrid. The Volt handles nimbly through a modest slalom course and stops nicely. The car’s 1.4L engine did not engage during the test drive.

The Volt’s electric motor generates 90 kW (121 hp) of peak power in normal operation and 110 kW (147 hp) in sport mode. GM says that there will be additional drive modes for the car once production begins.

The Volt bristles with computers and advanced electronics connected by 1.7 miles (2.8 km) of wiring.

GM engineers and other drivers have racked up more than 500,000 test miles (805,000 km) so far over a broad range of driving environments, including up and down Pikes Peak, CO.

Warnke tells Ward’s he, personally, has driven a Volt at more than 100 mph (161 km/h) on the test track in both pure electric mode and with the IC engine-generator engaged, although the production car will be electronically limited to 100 mph. Driving between 45-50 mph (72-80 km/h) optimizes battery range, he says.

GM contends most Volt buyers should complete all their daily driving exclusively within the battery’s range of 40 miles (64 km), without requiring the 1.4L engine generator to kick on and keep the battery charged.

There are more than 200 lithium-ion cells in the Volt's battery pack, which will be assembled at the auto maker’s new facility in Brownstown Twp., MI. LG Chem Ltd. makes the cells in South Korea. The battery pack has 150 unique parts numbers, and 142 of them are GM parts.

Warnke says 20,000 miles (32,000 km) of the Volt test driving is actually like 100,000 miles (161,000 km) of conventional driving by consumers. That's because the engineers push the pre-production cars attempting to find potential defects or glitches. However, he declines to specify any problems discovered in the shakedown.

One of the pre-production cars has accumulated more than 66,000 test miles (106,000 km). GM has conducted more than 20 crash tests so far.

The Volt initially will be introduced in California, Michigan and here in the nation’s capital.

Beginning in May, Hamtramck will build 100 additional pre-production Volts for further testing. Later, the plant will assemble at least 150 more evaluation units.

After Job 1 in November, GM plans to ramp up production slowly through the early part of 2011.

After initial sales in the three U.S. markets, the Volt will be offered in Canada, Europe and China. Sales in China may begin in the summer of 2011.