Air-fuel ratio control device of an internal combustion engine

摘要

An air-fuel ratio control device of an internal combustion engine having a carburetor. An air bleed passage is connected to a fuel outflow passage of the carburetor, and an electromagnetic control valve is arranged in the air bleed passage. The control valve is controlled by the detecting signal of an oxygen concentration detector arranged in the exhaust passage so that the air-fuel ratio of a mixture fed into the cylinder of an engine becomes equal to the stoichiometric air-fuel ratio. When the vehicle is decelerated, the mean value of the potential level, which has been applied to the electromagnetic control valve before deceleration, is stored. When the throttle valve is opened during the deceleration and, then, the oxygen concentration detector detects that a rich air-fuel mixture is fed into the cylinder of the engine, the above-mentioned mean value is instantaneously applied to the electromagnetic control valve.