LPG – Liquefied Petroleum Gas – Autogas

Posted by Krzysztof Lis on July 1, 2008

Liquefied Petroleum Gas, abbreviated as LPG, is an internal combustion engine fuel, a mixture of propane and butane. It is an alternative to gasoline / petrol, in some countries it is very popular. In Poland, where I live, it’s very popular because it’s price is less than half of gasoline price! Because of that the cost of autogas (common name for LPG) conversion is returned pretty quick.

LPG can’t be considered as a real petroleum alternative. Why? In most cases it’s derived from the crude oil. Only in some cases it is manufactured in natural gas mines.

It is important to know that most new cars can use autogas with no trouble at all, as they’re prepared for this fuel by manufacturers.

LPG / autogas conversion

Most of the cars fitted with autogas conversion have spark ignition engines. You start the engine on gasoline, let it heat up a little, and then switch to LPG. You use it during the entire journey. The conversion consists of:

• filler,
• tank,
• converter (vaporiser – using warm cooling water helps the gas to vaporise, as it is stored in the liquefied phase),
• injectors,
• hoses, controller and stuff like that.

This subject will be covered in more details in one of my future posts here.

LPG in diesels

You can use LPG in diesel engines, but under certain conditions.

LPG won’t ignite on the compression itself, as it has very high octane rating. You need to install spark ignition system to the diesel engine or leave small amounts of diesel fuel injected into the combustion chamber. The diesel ignites soon after it’s injected and ignites the autogas/air mixture.