| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration of running performance of an internal combustion engine or emission due to deviation in the control gain of an air-fuel ratio feedback correction from an optimal value. SOLUTION: If the control gain of an air-fuel ratio feedback correction deviates from a optimal value due to piece-to-piece difference of an engine 11, wherein the fuel is injected and supplied directly into a combustion chamber 16, the running performance is deteriorated based on increase of torque fluctuation following such a deviation, or the emission is deteriorated based on delay in the air-fuel ratio reaching to the ideal air-fuel ratio following the deviation. However, if the torque fluctuation is increased due to the deviation of the control gain from an optimal value, control gain is modified according to the degree of the torque fluctuation. As a result, deterioration in the running performance following the increase of the torque fluctuation is suppressed, so that deterioration of both running performance and emission can be made compatible.
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