The Chevrolet Volt is a plug-in hybrid electric vehicle manufactured by the Chevrolet division of General Motors. The Volt has been on sale in the U.S. market since mid-December 2010, and displaced the Toyota Prius as the most fuel-efficient car sold in the United States.
According to General Motors the Volt can travel 25 to 50 miles (40 to 80 km) solely on electrical power supplied by a 16 kW·h (10.4 kW·h usable) lithium-ion battery; The EPA found in tests using varying driving conditions and climate controls, the all-electric range averaged 35 miles (56 km), with an energy consumption of 36 kWh per 100 miles (810 kJ/km), and the total range (using battery power first then electricity generated by the on-board gasoline-power generator) is 379 miles (610 km). EPA rated the Volt's combined city/highway fuel economy at 93 miles per gallon gasoline equivalent in all-electric mode, and at 37 mpg-US (6.4 L/100 km; 44 mpg-imp) in gasoline-only mode, for an overall fuel economy rating of 60 mpg-US (3.9 L/100 km; 72 mpg-imp) combined.
The Volt's lithium-ion battery pack can be charged by plugging the car into a 120-240VAC residential electrical outlet. No external charging station is required. After the Volt battery is depleted, it switches to extended range mode, when a small 4-cylinder internal combustion engine burns premium gasoline to power a 55 kW (74 hp) generator supplying the electrical power to extend the Volt's range. In addition, while in extended range mode and travelling at highway speeds, the engine can engage mechanically via a clutch to combine with the electric motors for propulsion. The electrical power from the generator is sent primarily to the electric motor, with the excess going to the batteries, depending on the state of charge (SoC) of the battery pack and the power demanded at the wheels.