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. After the completion of the warm-up of an engine, the opening area of the control valve is maintained within a fixed range. Before the completion of the warm-up of an engine, the opening degree of the control valve becomes larger than the above-mentioned fixed range.