FFVs

FFV stands for flex-fuel vehicle, a type of automobile designed to run on more than one fuel option, most commonly gasoline or ethanol blends up to 85% ethanol (E85).

Operation: The engine management system adjusts the air–fuel mixture and ignition timing based on ethanol content. A fuel composition sensor or spectral reading, along with adaptive fuel trims, enables use of varying ethanol percentages. Components in the fuel system and seals are ethanol-compatible.

History and adoption: FFVs became widely offered in North America in the late 1990s and early 2000s, with manufacturers such as Ford and General Motors leading the market. In Brazil, flex-fuel vehicles have been common since the late 1990s, exploiting abundant sugarcane ethanol; many Brazilian vehicles can operate on any blend from pure gasoline to pure ethanol.

Performance and economy: Ethanol has a lower energy density than gasoline, so mpg can be lower on high-ethanol blends, though torque may increase in some engines. Fuel economy and emissions depend on blend and driving, and in places with cheap E85 FFVs may reduce fuel costs. Ethanol fuel availability varies by region, affecting practical use.

Limitations and considerations: Ethanol can be more corrosive to certain materials, so manufacturers use ethanol-resistant components. Cold-starting may be affected in very cold climates, and performance may differ by blend. Not all fueling stations offer high-ethanol blends.