[SportsJunky]

http://en.wikipedia.org/wiki/Chevrolet_Volt

For trips less than about 40 miles (64 km) per recharge cycle, the Volt will not use any on-board gasoline. Assigning a fuel consumption value which only refers to on-board fuel might not be appropriate.[61] Once the Volt's battery has discharged to its lower limit set-point, the Volt's range-extending gasoline engine is expected to get from approximately 50 mpg-US (4.7 L/100 km; 60 mpg-imp) to as much as 150 mpg-US (1.6 L/100 km; 180 mpg-imp) depending on its run-time duty cycles. Once the battery has been recharged to an upper limit set-point (by the gasoline engine driven, 53 kW on-board generator), the internal combustion engine will again shut off. The variables that contribute to the specific duty cycle of the internal combustion engine will need to be factored in to the Volt's final fuel economy rating as determined by the EPA.[62] On August 11, 2009, GM released their estimated EPA urban cycle (aka city) fuel economy rating for the Volt of 230 mpg-US (1.0 L/100 km; 280 mpg-imp).[63][64]