Abstract: A system is described for improving performance of spark ignition, internal combustion engines using fuels such as liquified petroleum gas (LP-gas), which have conventionally been stored as a liquid and delivered to the engine as a vapor. This system stores such fuels as liquids (10) and delivers the fuel to the engine inlet air stream as a liquid. The absorption of heat by the vaporizing fuel lowers engine inlet air temperature, increasing its density and permitting more fuel to be burned in each cycle. Vaporizing heat in a pilot line (17) provides the cooling to the liquid fuel in the main fuel line (20) and provides fuel to maintain the engine idling. A member (27) slides within a fuel delivery chamber (25) for covering or uncovering a series of orifices (26) through which the liquid fuel passes into the inlet air stream of the engine.

Abstract: A system is described for improving performance of spark ignition, internal combustion engines using fuels such as liquified petroleum gas (LP-gas), which have conventionally been stored as a liquid and delivered to the engine as a vapor. This system stores such fuels as liquids (10) and delivers the fuel to the engine inlet air stream as a liquid. The absorption of heat by the vaporizing fuel lowers engine inlet air temperature, increasing its density and permitting more fuel to be burned in each cycle. Vaporizing heat in a pilot line (17) provides the cooling to the liquid fuel in the main fuel line (20) and provides fuel to maintain the engine idling. A member (27) slides within a fuel delivery chamber (25) for covering or uncovering a series of orifices (26) through which the liquid fuel passes into the inlet air stream of the engine.