Apparatus and method for fueling an internal combustion engine

Claim 1

In combination with an internal combustion engine fueled by gasoline as the sole source of fuel for the engine, and having a fuel intake system for the engine, a carburetor coupled to the fuel intake system and an emission control system for removing hydrocarbon and carbon monoxide from engine exhaust, first means for separating low boiling gasoline components from higher boiling gasoline components of the gasoline and mixing said low boiling components with air in a controlled manner to provide a gaseous fuel having a predetermined air to fuel ratio which is about stoichiometric or leaner, said first means including means for holding gasoline and providing a vapor space above the gasoline, a fuel line in communication with the fuel intake system of the internal combustion engine and said vapor space, the demand for the flow of fuel through said fuel line varying with changing operating conditions of the engine, and means for introducing air into the gasoline and forming in the vapor space a gaseous mixture of air and low boiling gasoline components; said introducing means including an air port in communication with the fuel line and atmosphere, a fuel port in communication with the fuel line and the vapor space, said ports each having means which vary the size of port openings including a first element for adjusting the ratio of the opening areas in accordance with said predetermined air-fuel ratio and a second element for closing said ports until a predetermined negative pressure substantially greater than the pressure of the head of gasoline in the container means has been established in the fuel line, so that air will bubble through the gasoline in the container means, said second element exposing said ports when said predetermined negative pressure has been achieved; second means for bypassing the carburetor during startup of the engine and fueling the engine directly through the fuel intake system with said gaseous fuel, and third means operable when the emission control system has reached a predetermined elevated temperature for discontinuing operation of the second means and switching fueling of the engine over to the control of the carburetor.