| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for diagnosing abnormalities in a gas sensor, capable of accurately determining the abnormal state of the gas sensor that a leak is produced between connection terminals by the main cause, such as the production of steam, in a housing accommodating a detection element. <P>SOLUTION: An oxygen sensor 1 is connected to an abnormality diagnosis circuit 5, the oxygen sensor 1 is exposed to the atmosphere of a known concentration of oxygen. The current-carrying path on the power supply potential side of a heater 13 is connected to a battery via a switch 53. Furthermore, the current-carrying route on the reference potential side of the heater 13 is set to an open circuit state. Accordingly, if the current-carrying path on the power supply potential side of the heater 13 is connected, current will not flow to the heater 13; as a result, the sensor output value of the detection element 12, having a current-carrying route independent of that of the heater 13, is acquired; and if the sensor output value indicates a large value (large fluctuation is produced), the oxygen sensor 1 can be determined as being in an abnormal state. <P>COPYRIGHT: (C)2011,JPO&INPIT |
