SENSOR ABNORMALITY DETECTION DEVICE AND VEHICLE EQUIPPED WITH SAME

摘要

PROBLEM TO BE SOLVED: To detect abnormality of a rear exhaust gas sensor arranged in a downstream of a catalytic converter with sufficient accuracy.

SOLUTION: An engine ECU 50 performs control alternately setting target air fuel ratio to a predetermined lean air fuel ratio until an output value of the rear exhaust gas sensor 36 indicates lean and to a predetermined rich air fuel ratio until an output value of the rear exhaust gas sensor 36 indicates rich. Oxygen occlusion quantity of an exhaust emission control catalyst 31 is calculated based on output value of the rear exhaust gas sensor 36. Oxygen consumption quantity of oxygen consumption composition included in the catalytic converter 30 is corrected based on temperature of the exhaust emission control catalyst 31. Oxygen occlusion quantity is corrected based on corrected oxygen consumption quantity and temperature of the exhaust emission control catalyst 31. It is determined whether oxygen occlusion quantity exceeds a predetermined value (value adding margin to the maximum oxygen occlusion quantity calculated beforehand) or not. If the value exceeds the predetermined value, abnormality of the rear exhaust gas sensor 36 is detected.

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