| 摘要 |
PROBLEM TO BE SOLVED: To diagnose the breakage of a sensor, even when the breakage of the sensor is minute. SOLUTION: In a case when the minute breakage is found on the sensor of an oxygen sensor 14, the exhaust existing outside of the sensor intrudes to the inside of the sensor when a pressure in an exhaust passage 6 is high, and an output signal of the oxygen sensor 14 is converted from a rich signal to a lean signal. When the conversion from the rich signal to the lean signal is found in accompany with the increase of the amount of sucked air as the parameter relating to the pressure in the exhaust passage 6, the probability that the conversion is caused by the breakage of the sensor, is high. That is, the breakage can be determined even when the breakage of the sensor is minute, on the basis of that a ratio of the number of times of conversion in accompany with the increase of the amount of sucked air, to the total number of times of conversion from the rich signal to the lean signal, is more than a specific value. COPYRIGHT: (C)2005,JPO&NCIPI
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