Autogas is the common name for liquefied petroleum gas (LPG) when it is used as a fuel in internal combustion engines invehicles as well as in stationary applications such as generators. It is a mixture of propane and butane.
Autogas is widely used as a "green" fuel, as its use reduces CO2 exhaust emissions by around 15% compared to petrol. One litre of petrol produces 2.3 kg of CO2 when burnt, whereas the equivalent amount of autogas (1.33 litre due to lower density of autogas) produces only 1.5 * 1.33 = 2 kg of CO2 when burnt. It has an octane rating (MON/RON) that is between 90 and 110 and an energy content (higher heating value—HHV) that is between 25.5 megajoules per litre (for pure propane) and 28.7 megajoules per litre (for pure butane) depending upon the actual fuel composition.

Characteristics of LPG
LPG – Liquefied Petroleum Gas
Mixture of Propane & Butane (95/5)
Heavier than air
Ignition temperature of LPG is 450 0C

Benefits of LPG
Re-fuelling time in vehicle is similar to petrol
Vehicle conversion is significantly economical than CNG
20 kg LPG gives around 350 to 400 km run.

Why use LPG?
Unavailability of CNG and continuous increase in petrol & diesel prices invoke the need of cheaper alternative fuel.

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