| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress the occurrence or the like of an accidental fire resulting from the execution of emission-amount reduction control at the occurrence of imbalance between air/fuel-ratio cylinders. <P>SOLUTION: An "imbalance index value" indicating the magnitude of a difference between per-cylinder air/fuel ratios (imbalance between air/fuel ratio cylinders) is acquired on the basis of an output value of an air/fuel ratio sensor which is arranged upstream of a catalyst. When the magnitude of the imbalance between the air/fuel ration cylinders indicated by the imbalance index value is not smaller than a first level and smaller than a second level which is larger than the first level, the execution of the emission-amount reduction control is "limited", and when the magnitude is not smaller than the second level, the execution of the emission-amount reduction control is "prohibited". As the emission-amount reduction control, there are listed purge control, EGR control, AI increasing control, cold VVT control, catalyst warmer retardancy control, SCV control or the like. <P>COPYRIGHT: (C)2012,JPO&INPIT |
