Patent ID: 7792630

Claim:
A control system for an internal combustion engine, for controlling an amount of fresh air to be supplied to a cylinder and an amount of fuel to be supplied to the cylinder to thereby control an air-fuel ratio of a mixture in the cylinder such that an air-fuel ratio mode is switched between a lean mode in which the air-fuel ratio is controlled to a lean side air-fuel ratio and a rich mode in which the air-fuel ratio is controlled to a rich side air-fuel ratio a richer than the lean side air-fuel ratio, comprising: fresh air amount-detecting means for detecting the amount of fresh air; lean-mode target fresh air amount-setting means for setting a target fresh air amount for the lean mode, which serves as a target of the fresh air amount in the lean mode; lean-mode fresh air amount controlling means for controlling the fresh air amount such that the fresh air amount becomes the set target fresh air amount for the lean mode, in the lean mode; rich-mode target fresh air amount-setting means for setting a target fresh air amount for the rich mode, which serves as a target of the fresh air amount in the rich mode; rich-mode fresh air amount controlling means for controlling the fresh air amount such that the fresh air amount becomes the set target fresh air amount for the rich mode, in the rich mode; operating condition-detecting means for detecting an operating condition of the engine; fuel injection timing-setting means for setting fuel injection timing of the fuel to be supplied to the cylinder according to the detected operating condition of the engine; and fuel injection timing-correcting means for correcting the fuel injection timing according to a difference between the target fresh air amount calculated immediately before switching of the air-fuel ratio mode, and the detected fresh air amount, upon switching of the air-fuel ratio mode.