Flexible Fuel Vehicles
Flexible fuel vehicles (FFVs) have an internal combustion engine and are capable of operating on gasoline and any blend of gasoline and ethanol up to E85 (or flex fuel). E85 is a gasoline-ethanol blend containing 51% to 83% ethanol, depending on geography and season. According to IHS Automotive, there are nearly 20 million FFVs on U.S. roads today. However, many flexible fuel vehicle owners don't realize their car is an FFV and that they have a choice of fuels.
Other than employing an ethanol-compatible fuel system and powertrain calibration, FFVs are similar to their conventional gasoline counterparts. While fuel economy (miles/gallon) is generally lower with increased levels of ethanol (due to the lower energy content in ethanol as compared to gasoline), many FFVs have improved acceleration performance with higher ethanol blends. For additional information on the fuel economy and performance of FFVs, see Effects of High-Octane Ethanol Blends on Four Legacy Flex-Fuel Vehicles, and a Turbocharged GDI Vehicle(PDF) and Fuel Economy and Emissions of a Vehicle Equipped with an Aftermarket Flexible-Fuel Conversion Kit.
For fleets that have to comply with federal acquisition regulations, flexible fuel vehicles are considered alternative fuel vehicles (AFVs) under the Energy Policy Act of 1992.