| 摘要 |
PROBLEM TO BE SOLVED: To continue air-fuel ratio control without causing problems including degradation of drivability and emission, torque shock and the like when a target air fuel ratio is significantly changed or immediately after open loop control is shifted to feedback control. SOLUTION: A CPU 31 in an ECU 30 sets the target air fuel ratio, performs compensation according to lean or rich grade of the target set and feedback-controls actual air fuel ratio of exhaustion gas exhausted from an engine 1 for the target air fuel ratio. For example, in the case of shifting from theoretical air fuel ratio feedback control to lean feedback control, when significant change of the target air fuel ratio is judged, the CPU 31 temporarily stops the feedback control and restarts the feed back control at the time that the deviation between actual air fuel ratio and the target air fuel ratio becomes equal to a predetermined value or less. COPYRIGHT: (C)2004,JPO
|
