| 摘要 |
PROBLEM TO BE SOLVED: To provide an irregularity detection device capable of determining irregularity of an internal combustion engine without an error. SOLUTION: Accumulation of oxygen occlusion quantity Cmax is performed (step 106) when output of an oxygen sensor is rich or lean. In a step 108, it is determined whether a condition where time during which state of high intake air quantity under which intake air quantity Ga is high continues is X sec or longer and reduction quantity of intake air quantity is Y g or more is satisfied or not. In this embodiment, temperature of a catalyst is regarded as high if high intake air quantity state continues X sec or longer. Also, irregularity determination is prohibited to prevent wrong determination if temperature of the catalyst is high and reduction quantity of intake air quantity is Y g or more. Consequently, simultaneous satisfaction of two conditions means necessity of prohibition of irregularity determination in this step, oxygen occlusion quantity is cleared and irregularity determination is prohibited in a step 114. COPYRIGHT: (C)2006,JPO&NCIPI
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