To provide a combustion control system for a multi-cylinder internal combustion engine capable of sensing fluctuation in a combustion state among cylinders for effectively eliminating fluctuation in a combustion state.
A/F lean control is carried out for temporarily shifting an air-fuel ratio to a lean side prior to fuel cut movement accompanied by accelerator-off operation. If a misfire accompanied by the execution of the A/F lean control may occur, the correction of increasing the fuel injection amount of the cylinder to an accidental fire is performed after the termination of the fuel cut movement. If the misfire does not occur, the air-fuel ratio is shifted further to the lean side when succeeding A/F lean control is executed, and the operation is repeated until the misfire occurs in part of the cylinders. If misfires may occur in a plurality of cylinders, the air-fuel ratio is shifted slightly to a rich side when the succeeding A/F lean control is executed.
MUTO YOSHIE
Kunitomi Go
Ashikita Tomoharu
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