| 摘要 |
An oxygen-sensor abnormality detecting device for detecting abnormalities in an Oz sensor for air-fuel ratio detection in an internal combustion engine. In exhaust passage 9, a converter 10 is installed which contains a three-way catalyst for removing three harmful components HC, CO, and NOx of automotive emission. In the catalytic converter 10, a catalyst temperature sensor 11 is installed which detects catalyst temperature of the converter. O2 sensors 12 and 13 are provided along the exhaust passage on the upstream side and the downstream side of the catalytic converter 10. For the O2 sensors 12 and 13, the heaters 12a and 13a are provided for promoting the activity of the O2 sensors 12 and 13. Control circuit 15 checks the catalyst temperature and compares output voltages of the Oz sensors with reference levels under an inactive temperature state of the catalytic converter. The control circuit detects abnormalities in the downstream sensor by comparing results of the comparison of the sensor output voltages. |
