| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent the occurrence of misfire or the like resulting from executing emission amount reduction control when an air-fuel ratio between-cylinders imbalance occurs. <P>SOLUTION: An "imbalance index value" representing a magnitude of a difference between individual cylinder air-fuel ratios (air-fuel ratio between-cylinders imbalance) is obtained based on an output value of an air-fuel ratio sensor arranged upstream a catalyst. When a magnitude of the air-fuel ratio between-cylinders imbalance represented by the imbalance index value is equal to or more than a first degree and less than a second degree larger than the first degree, execution of the emission amount reduction control is "limited", while when the magnitude is equal to or more than the second degree, the execution of the emission amount reduction control is "prohibited." The emission amount reduction control includes purge control, EGR control, AI amount increasing control, cold VVT control, catalyst warm-up retard angle control, SCV control, and the like. <P>COPYRIGHT: (C)2012,JPO&INPIT |
