Air/fuel ratio control system for an internal combustion engine

摘要

An air/fuel ratio control system for an internal combustion engine includes an oxygen concentration sensor for sensing the oxygen concentration in the exhaust gas of the engine, and a correction value setting device which determines a correction value corresponding to an output signal of the oxygen concentration sensor obtained when the fuel cut operation of the engine has continued for more than a predetermined time period. The output signal of the oxygen concentration sensor is corrected by the correction value during the engine operation other than the fuel cut operation.