Friday, December 21, 2007

Chevrolet Volt concept

Chevrolet Volt, a concept from GM showcasing its latest "E-Flex" technology. This features electric motors to propel the vehicle, with an internal combustion engine to provide recharging, as well as provision for ordinary plug-in charging. The Volt has a 3 cylinder turbocharged 1-litre powerplant to provide the recharging capability. This engine has a fuel tank of 54.5 litres capacity and is also able to run off E85 ethanol. The system can be adapted to suit various markets, and diesel, petrol, hydrogen and ethanol are mentioned as examples of the fuels that could be used by the recharger motor. Actual propulsion for the Volt is via a 160 bhp (120 kW) electric motor which provides a respectable 8 second sprint time to 60 mph, and a top speed of around 190 km/h (120 mph). The range is claimed to be 640 miles, including on-the-go recharging from the petrol engine, and a mere 40 miles without. The lithium-ion batteries can be recharged in about 6.5 hours using the plugin charger. The body is an attractive 4 seater with 4 doors and a lift-up tailgate. It is a small car overall, with a length of just 4318 mm, a width of 1791 mm and height of 1336 mm. The wheels are very large, at 21 inches, but are narrow to reduce rolling resistance. 195/55 R 21 tyres are fitted.

This general layout is considered a plug-in series hybrid design since mechanical power initially drives the generator, which in turn charges the battery pack. Power is then drained from the batteries to run the electrical motors which move the vehicle. The internal combustion engine does not have any mechanical linkage to the wheels (unlike current vehicles such as the Toyota Prius), and can run at a constant speed for optimal efficiency.
GM plans to keep the lithium-ion battery in a state-of-charge (SOC) range of between 30% and 80%, with the on-board generator starting to recharge the battery at the 30% level.GM has decided on a new descriptive terminology distinct from calling it a hybrid. They are calling the Volt an E-REV, for "extended-range electric vehicle".General Motors said it will have the Volt on the market in 2010. To help spur battery research, GM selected two companies to provide advanced lithium-ion batteries: Compact Power and Continental Automotive Systems. However, on August 9, 2007 GM selected A123Systems to provide batteries. Clearly, battery technology will have a large impact in determining the success of the car.

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