GLOSSARY

General Motors’ name for their proprietary automobile variable displacement technology. Active Fuel Management allows a V8 engine to "shut down" half of the cylinders under light-load conditions to improve fuel efficiency.

Any materials or substances that can be used as fuel outside of conventional fuels. Popular alternative fuels include biodiesel, bioalcohol (methanol, ethanol, and butanol), chemically stored electricity (batteries and fuel cells), hydrogen, non-fossil methane, non-fossil natural gas, vegetable oil and other biomass sources.

A measurement of how much fuel is required to produce a specific amount of engine power.

Conventional materials or substances that can be used as fuel. Conventional fuels include fossil fuels (i.e. petroleum, coal, propane, and natural gas) and nuclear materials (i.e.Uranium).

Technology that reduces engine fuel consumption and emissions by closing the intake and exhaust valves for a particular cylinder and releases trapped exhaust gases from the combustion chamber. The compression and decompression of trapped gases allows the engine to operate more efficiently.

The process of injecting highly pressurized gasoline directly into the combustion chamber of each cylinder for improved engine efficiency.

Vehicles that are powered by an electric motor which use rechargeable battery packs instead of conventional fuels.

An agency of the U.S. federal government that is responsible for the protection of human health and the environment through legislation.

Vehicles that are powered by gasoline or a blend of up to 85% ethanol (E85).

The distance traveled per unit of fuel used. Fuel economy is most commonly measured by miles per gallon (MPG).

EPA mileage (MPG) assigned to new vehicles.

Energy efficiency or total output of a particular vehicle model. Energy efficiency is a ratio of range units per a unit amount of input fuel (gasoline, diesel, etc.).

Ratio of the total miles traveled per the number of gallons of gasoline burned.

Vehicles that are powered by two distinct sources. A common hybrid vehicle is the hybrid electric vehicle (HEV), which is powered by both an internal combustion engine and one or more electric motors.

Miles per gallon

Total miles a vehicle can cover on just one tank of gas.

Air compressor that increases engine power by forcing the induction of an internal combustion engine.

Gas compressors that increase engine power by compressing the density of air that enters the engine.

Automobile technology that allows the lift, duration or timing of the intake and exhaust valves to change while the engine is in operation. VVT alters cam timing, which results in greater engine efficiency and power. (For more information visit http://www.fueleconomy.gov/feg/tech_engine_more.shtml).