Autogas is the common name for liquefied petroleum gas (LPG) when it is used as a fuel

Fuel

Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...

 in internal combustion engine

Internal combustion engine

The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

s in vehicles as well as in stationary applications

Stationary engine

A stationary engine is an engine whose framework does not move. It is normally used not to propel a vehicle but to drive a piece of immobile equipment such as a pump or power tool. They may be powered by steam; or oil-burning or internal combustion engines....

 such as generator

Generator

Generator may refer to:* Electrical generator* Engine-generator, an electrical generator, but with its own engine.* Generator , any of several closely related usages in mathematics.Computing:...

s. It is a mixture of propane

Propane

Propane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...

 and butane

Butane

Butane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or...

.

Autogas is widely used as a "green" fuel as it decreases exhaust emissions

Automobile emissions control

Vehicle emissions control is the study and practice of reducing the motor vehicle emissions -- emissions produced by motor vehicles, especially internal combustion engines....

. In particular, it reduces emissions by around 35% compared to petrol

Gasoline

Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

. One litre of petrol produces 2.3 kg of when burnt, whereas the equivalent amount of autogas produces only 1.5 kg of when burnt.