General Motors Corp., the Detroit-based automaker often maligned for not sticking with electric cars in recent years, showed off a newfangled electric car early in 2007 that could have lots of us clamoring for electric transport.

The intriguing aspect of the Chevrolet Volt concept unveiled at the 2007 North American International Auto Show in Detroit isn't that it can be plugged into an outlet, charged and then operate on electric power pulled from a substantial, onboard battery.

It's that the Volt also carries an onboard "engine" that, unlike conventional cars, is not connected directly to the wheels of the car. It's there just to make electric power if the battery pack were to be depleted.

The lack of mileage range of pure plug-in vehicles has been the Achilles heel of electric cars and led to GM dropping its iconic EV1 electric car in 2003, as highlighted in Chris Paine's 2006 movie documentary that was noted by many environmentalists.

But with the newly envisioned Volt, a driver could have the best of both worlds.

If a commuter doesn't drive more than 40 miles round trip, he or she may have enough electric power from the battery and not need to tap the car's onboard engine. So he or she may forego stopping at the gas station for an extended period of time, said GM spokesman Scott Fosgard.

Yet, with this engine riding along in the Volt, a driver could be assured he or she won't get stranded somewhere on an extended trip because of a lack of electric power.

Best of all, the onboard engine could be anything from a small, turbocharged gasoline engine that also can burn ethanol to a diesel engine burning biodiesel or even a hydrogen fuel cell.

A New Take on a Hybrid
In a sense, the Volt is a concept—emphasis on concept at this point—that takes a different approach from today's gas-electric hybrid vehicles such as GM's Saturn Vue Green Line, Toyota's Prius and Ford's Escape Hybrid.

Current hybrids still rely primarily on gasoline engine power for propulsion. Electric power is only a supplement that kicks in now and then.

In contrast, the Volt relies primarily on electric power and supplements its electric power supply by creating electricity, when it has to, via the onboard engine.

Let me emphasize that in the Volt, there is no mechanical connection between the onboard engine and the wheels. Propulsion power comes from the battery pack at all times.

GM officials call this system E-Flex. While they caution that batteries need to be developed first that can handle the demands of the Volt, they're excited about the considerable conservation of oil and reduction in car emissions that E-Flex could generate.

Note that Toyota sells Priuses in Japan that can be plugged in and charged. But Toyota officials warn that rigging Priuses in the United States to be a plug-in hybrid can void the car's warranty.

The reason: Drivers in the United States tend to drive longer distances than those in urban Japan, and the Prius battery pack isn't built to be drawn down for these longer-distance trips.

In fact, one of the fascinating elements of Toyota's gas-electric hybrid vehicles that use the company's Hybrid Synergy Drive System is how much effort is put into keeping the battery pack in an optimal middle-range operating mode.

Toyota engineers discovered that the life of the battery pack is greatly improved if the battery isn't drawn all the way down. So as people drive, the hybrids' electronics manage the inter-workings of the hybrid battery and gasoline engine to keep the battery in the optimal range.

A Solution?
An exciting element of E-Flex is its adaptability to various transportation fuels.

It is, as Nick Zielinski, chief engineer at GM, put it, like "a plug-and-play electric motor" that can derive electricity from a number of fuel sources.

E-Flex also is surprisingly practical, given that half of U.S. households have daily mileage of less than 30 miles per day, and 78 percent of daily work commuters travel 40 miles or less per day, according to Tony Posawatz, vehicle line director at GM.

The Volt concept car could travel "40 miles as a pure electric vehicle based on simulations based on the (federal government) city driving cycle," he said.

Different From EV1
The Volt, with its E-Flex system, also is a far cry from the EV1, which became a cult car among some wealthy Southern Californians, including comedian Phyllis Diller.

If it goes into production—and that's still an "if"—the Volt could be charged in 6.5 hours using an everyday household circuit of 110 volts, GM said. A full charge for the EV1 took eight hours and a special, 220-volt circuit.

There also would be a quick charge feature on the Volt to provide a fast infusion of electric power when needed. The EV1 had no quick-charge feature.

The Volt's fuel tank—for gasoline, diesel, whatever—would hold about 12 gallons, GM said. Meantime, the EV1 had no onboard electric power supply beyond the battery pack, so there was no fuel tank.

The Volt is an accommodating, 4-door sedan with room for four or five passengers. The EV1 was a rather cramped, 2-door 2-seater.

Top speed in the Volt is expected to be at least 120 miles an hour. Top speed in the EV1 was 70 mph.

And most importantly, if the Volt comes together the way GM engineers plan, it could be able to travel 640 city miles—nearly double the mileage of many of today's gasoline-only vehicles—before needing a fill-up and a charge. In contrast, the top city mileage in the EV1 was between 60 and 90, GM said.

Battery Work Needed
How soon can the Volt get to dealerships? Right now, the car is not slated for production and is not priced. Batteries are the big stumbling block.

GM engineers say they're looking at advancements in lithium ion batteries that would fit the Volt's needs and might come in 2010 or 2012.

But they could come sooner.

Officials at GM, Ford Motor Co. and the Chrysler Group of DaimlerChrysler have already sent a letter to the Bush administration asking that it triple money for government-funded battery research.

There's also the issue of educating consumers. CNW Marketing Research Inc. of Bandon, Ore., found a focus group of car buyers likely wouldn't be able to grasp the technology in a traditional 30- or 60-second commercial.

Yet, once the Volt's technology was explained, it became the car's "most-liked feature" overall, CNW reported.

After the new technology, men also liked the Volt's muscular exterior styling, while women pointed to the environmentally friendliness of the car and the front-end design.

Ford Shows a Plug-In, Too
Ford, by the way, showed lawmakers its own concept version of a plug-in hybrid a few weeks after GM's Chevy Volt debuted.

Ford's futuristic plug-in hybrid is an Edge crossover that's designed to use a hydrogen-powered fuel cell to generate onboard electricity to power the vehicle when plug-in electricity isn't available.

But where the Volt could go for an estimated 600-plus miles using electricity stored in the battery pack and by generating ongoing electricity from its gas engine, the Ford Edge hybrid could travel some 225 miles. The mileage limitation stems from onboard hydrogen storage constraints.

Who knows? Maybe in a few years, we'll all be watching a new documentary entitled "The Return of the Electric Car."

Ann Job is a freelance automotive writer.

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