Glossary

AT-PZEV — The state of California's classification for Advanced Technology Partial Zero Emission Vehicle.

BAS — Belt-alternator-starter mild-hybrid system that uses an electric motor/generator, regenerative braking and sophisticated engine control to improve fuel economy.

Biomass — Renewable organic materials such as wood, grasses and crops that can be converted into fuel.

CNG — Compressed natural gas, a fossil fuel that’s one of the cleanest-burning alternative vehicle fuels.

CVT — Continuously variable transmission, an advanced transmission design that uses belts and pulleys to smoothly and efficiently provide infinitely variable drive ratios, rather than relying on pre-set gears.

Ethanol — An alcohol fuel that’s typically made by fermenting corn in a process similar to beer brewing, but that can also be made from other renewable sources like woody grasses and waste biomass like corn husks.

EV — Electric vehicle; battery-electric vehicle.

FAS — Flywheel-alternator-starter mild-hybrid system that uses a compact electric motor between an engine and transmission, replacing the conventional alternator and starter motor.

Flex-Fuel Vehicle — Also flexible-fuel vehicle; a vehicle that can run on E85 ethanol, or gasoline or a mixture of the two. An onboard sensor determines the fuel mix in real time and adjusts engine-management computer settings accordingly.

Full Hybrid — A sophisticated hybrid system that uses both electric and internal combustion power to drive the wheels.

HEV — Hybrid-electric vehicle that uses two power sources for propulsion, typically an internal combustion engine and one or more electric motors.

HSD — Hybrid Synergy Drive is Toyota's second-generation gasoline/electric hybrid powerplant hybrid system used in the 2004-2006 model year Prius hybrids.

Idle Stop — A system that shuts an engine off while a vehicle is stopped, then restarts it automatically as a driver depresses the accelerator pedal.

IMA — Integrated Motor Assist, Honda's hybrid system.

ISG — Integrated starter-generator, a mild-hybrid system that uses a single component to combine the functions of an electric starter motor and generator.

Lightweighting — Reducing a vehicle's curb weight through the use of aluminum, plastic and other lightweight components.

Methanol — An alcohol fuel that’s typically made from natural gas, although it can also be made from coal or biomass sources like wood.

Mild Hybrid — A simpler and less expensive hybrid system that achieves modest mpg improvement.

Near-Zero Evaporative Emissions Systems — Also called Zero Evaporative Emissions Systems, these are fuel systems that use special fuel lines, gaskets, fuel tank and other fuel-system components to prevent toxic emissions from evaporating from fuel onboard. Hybrid vehicles tend to have near-zero evaporative emissions systems.

NiMH — An acronym for "nickel metal hydride", which is a type of battery, often rechargeable, used in hybrid electric vehicles and a number of consumer electronics.

Regenerative Braking — A system that generates electricity to recharge batteries while a vehicle is coasting or braking.

Strong Hybrid — GM's designation for a full-hybrid system.

SULEV — The state of California's classification for Super Ultra Low Emission Vehicle. SUVLEV-rated vehicles run 90 percent cleaner than the average new vehicle today.

THS — Toyota Hybrid System, Toyota's first-generation hybrid powerplant used in 2000-2003 model year Prius hybrids.

VCM — Variable Cylinder Management, Honda’s fuel-saving technology used in its 2006 Civic Hybrid and Accord Hybrid models that idles some cylinders during times of low power demand.

ZEV — The state of California's classification for Zero Emission Vehicle.

Zero Evaporative Emissions Systems — See Near-Zero Evaporative Emissions Systems.