| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately estimate HC emission quantity without receiving influence of previous misfire of an engine. Ž<P>SOLUTION: Misfire level [parameter for evaluating degree of deterioration of a combustion state (for example, heat generation quantity maximum value or the like)] is calculated based on cylinder pressure detected by a cylinder pressure sensor 22 each combustion stroke of each cylinder of an engine 11, it is determined in each cylinder if previous misfire level deteriorates worse than a prescribed value. As a result, if the previous misfire level does not deteriorate worse than the prescribed value, present HC emission quantity is estimated based on present misfire level since HC quantity remaining in a cylinder is very little. If the previous misfire level deteriorates worse than the prescribed value, present HC emission quantity is estimated with both of remaining HC quantity according to the previous misfire level and unburned HC generation quantity according to the present misfire level taken into account by estimating present HC emission quantity based on the previous misfire level and the present misfire level since HC quantity remaining in the cylinder is relatively large. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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