METHOD FOR CONTROLLING FAILURE DETECTION ERROR OF OXYGEN SENSOR, CAPABLE OF IMPROVING THE RELIABILITY BY WARNING THE GAP BETWEEN THE FRONT AND REAR OXYGEN SENSORS AND PREVENTING WRONG DECISION OF FAILURE OF THE OXYGEN SENSOR

摘要

PURPOSE: A control method of failure detection errors of an oxygen sensor is provided to reduce waste of time, and to improve the reliability by warning the gap between the front and rear oxygen sensors and preventing wrong decision of failure of the oxygen sensor. CONSTITUTION: An engine control unit controls the air fuel ratio by receiving engine rpm, the suction air amount, the throttle valve opening degree and signals from front and rear oxygen sensors in starting an engine, monitors the front oxygen sensor, and decides failure(S100,S110,S120). The engine control unit decides failure by monitoring the rear oxygen sensor(S130,S140). The fuel injection control signal is output by varying the desired air fuel ratio according to travel condition(S150). The failure of the rear oxygen sensor is detected, and the error of failure detection is decided(S160). The fuel amount feedback control is forbidden, and the engine check warning lamp control signal is output to a warning unit(S170,S180). The engine control unit deletes the failure code of the rear oxygen sensor in error of failure detection and returns to the main routine(S190).