LPG Fuel Systems

Emission inspection requirements for Liquid Petroleum Gas (LPG) systems are very similar to CNG. LPG systems use compressed propane. The pressure required to keep propane in a liquid state is roughly 200 psi. Therefore, the fuel tanks used to contain the propane are less costly than fuel tanks used for CNG systems. The BTU output from propane is higher than CNG but not as high as gasoline. Fuel mileage and power output from an engine equipped with a propane system is much closer to that of gasoline. Because the fuel used by LPG and CNG systems is in a gaseous state even when the engine is cold, they have better drivability and lower emissions (as compared to gasoline) during cold driving conditions.