Split vapor/liquid fuel supply system for internal combustion engines

A split vapor/liquid fuel supply system is described for an internal combustion engine having: an intake manifold leading to at least one combustion chamber, a fuel tank holding a liquid hydrocarbon fuel supply, a carburetor connected to the fuel supply for feeding fuel to the engine, air supply means for supplying engine intake air to the carburetor for mixing with the fuel. The improvement comprises a partial fuel vaporizer connected intermediate of the fuel tank and the carburetor including a housing defining a lower liquid fuel chamber, an upper vapor expansion chamber and a heat transfer plate separating the chambers and having small diameter holes. Means for maintaining liquid hydrocarbon fuel are within the liquid fuel chamber at a level beneath the perforated heat transfer plate. Means permit ambient air to enter the liquid fuel chamber beneath the level of the liquid fuel for percolation. Means connect the vapor expansion chamber to the air supply means of the carburetor, upstream of the carburetor where light hydrocarbon fuel components in vapor form are created by vacuum pressure within the vapor expansion chamber causing air to enter the liquid fuel chamber and percolate through and to expand bubbles of air passing throughmore » the heat transfer plate bearing fuel in vapor form for mixing with the main intake air stream prior to its passage through the carburetor. This provides an increased time factor of air/fuel mixing with the result of less liquid fuel needed by the engine, an increase in the speed of the flame front within the combustion chamber, an increase in portions of the fuel burned during the power stroke of the engine and less fuel waste during the engine exhaust stroke.« less