Fuel control system for automobile engine

Abstract

An automobile fuel control system for an automobile internal combustion engine includes a composition sensor for detecting the concentration of oxygen contained in the exhaust gases emitted from the engine, a mixing ratio control including a compensator for compensating for variations of the mixing ratio of the combustible air-fuel mixture being supplied to the engine, a temperature detector for detecting the temperature of the engine and for generating a first signal indicative of a first predetermined engine temperature and for generating a second signal indicative of a second predetermined engine temperature higher than the first predetermined engine temperature, and an exhaust gas recirculating system including an electromagnetically operated valve for selectively establishing and interrupting the communication between the exhaust passage and the fuel intake passage. The valve is operable in response to the generation of the first signal to establish the communication between the exhaust and intake passages while the ratio control generates an output pulse to the compensator in response to the generation of the second signal to adjust the mixing ratio to a value substantially equal to the stoichiometric value required for a three-way catalytic converter to work at its maximum conversion efficiency.