| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect a failure in exhaust gas sensor while discriminating it from a deterioration of a catalyst by using an element temperature control. <P>SOLUTION: In a device for detecting a failure in an exhaust gas sensor disposed on an exhaust gas tube, the output of the gas sensor is detected in a situation where the element of the sensor varies in temperature and is filtered. Further, the filtered output of the gas sensor is statistically processed by using a sequential square method. An output of the gas sensor obtained when the element is at a high temperature and an output of the gas sensor obtained when the element is at a low temperature are statistically processed and compared with each other, thereby detecting a failure in the gas sensor. The temperature of the element is controlled at a prescribed temperature by using a response designation type control. In this control, the element temperature is estimated based on the operating state of an internal combustion engine. <P>COPYRIGHT: (C)2004,JPO |
