| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fault detecting device which can accurately detect the fault of an air-fuel ratio sensor which is provided in an exhaust system of an internal combustion engine and in which the amplitude of an output signal is linearly changed in response to an oxygen concentration of an exhaust gas. <P>SOLUTION: The electronic controller 30 of the fault detecting device detects the fault of the air-fuel ratio sensor 10 provided in the exhaust tube 22 of the internal combustion engine 20. The air-fuel ratio sensor 10 linearly changes in the amplitude of the output signal in response to the oxygen concentration of the exhaust gas. The controller 30 compares a detected air-fuel ratio calculated based on the output signal of the air-fuel ratio sensor 10 with a target air-fuel ratio set based on an engine operating state, and detects the fault of the air-fuel ratio sensor 10 based on its compared result. The controller 30 monitors the change of the target air-fuel ratio, and inhibits the detection of the fault from the time when the presence of the fault is judged to the time when a predetermined time is elapsed. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
