| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method and a device for diagnosing an abnormal condition of a gas sensor with high precision. <P>SOLUTION: During operation of a gas concentration measurement device 1, an internal resistance Rpvs of a sensor main body 10a is periodically measured. When a measured Rpvs is lowered below a threshold 2, it is determined that an abnormal short circuit occurs. When a time change of Rpvs is greater than a threshold 1, occurrence of a short circuit or a break is determined. When the measured Rpvs is higher than a threshold 3 and the time change from the previously measured Rpvs is higher than a threshold 4, it is determined that a heater 10 is in an abnormal condition and diagnosis is carried out for determining whether an abnormal condition occurs in the gas concentration measurement device 1 or not. <P>COPYRIGHT: (C)2007,JPO&INPIT |
