Abstract: A self-regulating, fast-response fuel vaporizer is disclosed which is cape of promoting increased efficiency of combustion of the fuel supplied to a spark ignition engine throughout the entire working range of the engine. The vaporizer comprises an inlet conduit through which fuel-air mixture is admissible to the engine, the mixture being directly heated within the conduit by an exhaust conduit which intersects with the inlet conduit. Use is made in the design of the respective heat transfer surfaces, of an inherent effect that flow pulsations have upon heat transference between a gas flowing in a tube and the walls of that tube, to provide a selected inverse relationship between heat transfer coefficient and engine speed whereby automatic regulation may be achieved of the heat supplied to the fuel-air mixture for all engine speeds.

Abstract: A liquid fuel vaporizing device for an internal combustion engine wherein a heat pipe containing a heat transfer fluid having a boiling point up to 400.degree. C is disposed so that the heat transfer fluid transfers heat from a heat-receiving zone to a heat-discharging zone. The liquid fuel is vaporized in the heat receiving zone after being mixed with the main stream of air.

Abstract: A liquid fuel vaporizing device for an internal combustion engine wherein a heat pipe containing a heat transfer fluid having a boiling point up to 400.degree.C is disposed so that the heat transfer fluid transfers heat from a heat-receiving zone to a heat discharging zone which heat discharging zone is disposed to vaporize a mixture of said liquid fuel in the main portion or all of the combustion air.