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It has an electric motor and a conventional engine, and it can't yet be classified as a zero-emissions vehicle but whatever you do, don't call the Chevrolet Volt a hybrid.
It's an electric vehicle, says Johan Willens, the global director of advanced propulsion and environmental communications for General Motors. The electric motor drives the wheels at all times.
GM is asking the US Environmental Protection Agency to classify the Volt as a zero emissions electric vehicle for regulatory purposes.
If that's granted, the Volt could get a US Government rating of more than 2.8 litres/100km (100mpg) and would be the first mass-produced vehicle to get such a designation.
Normally, a vehicle is run on an EPA test loop to provide data for calculating fuel economy.
But for electrics, which have no emissions, the US government uses an Energy Department mathematical formula to translate energy use into an equivalent of miles per gallon. The Volt has a 16Kw lithium-ion battery pack that gives the Volt a range of around 65km, sufficient for most everyday use.
But what's different is the Volt's small petrol engine. Unlike the Toyota Prius, for example, the engine isn't coupled to the drivetrain but acts as a generator, recharging the battery when it's out of juice. That way Volt owners won't be stranded if they travel for more than 65km. We call it a range extender, says Willens. GM calls the concept E-REV extended-range electric vehicle and it'll play a major role in the company's environmental plans in the future.
The Volt was shown at Paris in production-ready form and it has changed since the original concept was unveiled at the Detroit Show last year. It is now much more rounded. Willens says the changes are needed to optimise aerodynamic efficiency, which adds precious kilometres to the range.
Volt will go on sale in the US at the end of 2010, but Europe is likely to receive other models using the E-REV concept, possibly a version of the next-generation Zafira people-mover. It will use the same platform as the Volt, but its practicality is more likely to appeal to European tastes than the Volt's four-door saloon. The system can drop in to other cars in the GM range, says Willens. What's more, the petrol generator could be replaced by fuel cells in the future, when the technology becomes available at the right price.
What has enabled GM to make an E-REV is the advance in battery with lithium-ion technology. Willens says the concept is not a new one.
"We were working on a similar four-door car under the EV-1 project in the 1990s, but it wasn't possible because of the battery technology."
He says most users won't travel for more than 65km a day, which could mean the generator is rarely used. This has created other issues, such as oil pooling in the generator, though Willens says GM has solutions for this.
