Auxiliary fuel feed and timing control system for internal combustion

Abstract

An auxiliary fuel system for an internal combustion engine which supplements the primary fuel means for delivering fuel through a carburetor passage to said engine. The auxiliary fuel system is comprised of first and second fuel valves placed in parallel which introduce extra fuel into the intake passage of the carburetor at heavy load conditions. The first fuel valve is of the diaphragm operated type and opens and closes as a function of the pressure in a first vacuum chamber being alternatively connected to either a vacuum source at the intake passage of the carburetor or to the atmosphere. A series of electromagnetic selector valves and check valves determine the pressure conditions within said vacuum chamber. The second fuel valve is also of the diaphragm operated type, but the diaphragm is actuated by a mechanical linkage system interconnected to the throttle valve. As in the first fuel valve, movement of the dash pot diaphragm is a function of the pressure in the dash pot vacuum chamber which communicates with either the carburetor intake passage or to the atmosphere. A spark advance system is functionally interconnected to said auxiliary fuel feed control system. An electrical switching system controls the operation of both the auxiliary fuel system and the ignition timing control system so that addition of fuel during sudden non-steady state accelerations from medium speeds is delayed, and the air-fuel mixture is maintained leaner than the stoichiometric ratio. Harmful components exhausted into the atmosphere are thus minimized.