| 摘要 |
PROBLEM TO BE SOLVED: To improve the follow-up property to an air-fuel ratio fluctuation in a residual cylinder group caused by dispersions in an air flow meter and a fuel injection valve under a forced synchronous control. SOLUTION: When this air-fuel ratio control device is provided with a means 38 independently feedback-controlling the air-fuel ratios of respective cylinder groups 32 and 33, and a means 39 forcibly synchronously controlling the phases of the air-fuel ratio fluctuations in the multiple cylinder groups 32 and 33 in satisfying prescribed conditions, the control means 39 is provided with a proportional component forced adding means 44 forcibly adding an ordinary-time proportional component in the same direction of the residual cylinder group 33 at the additional timing of the proportional component in a specific cylinder group 32; a means 45 adding an integral component based on the air-fuel ratio of an exhaust passage of the residual cylinder group 33 in a timing except for this timing; and a means 46 enlarging the proportional component to be added at a next proportional component forced adding timing than the ordinary time, when the air-fuel ratio of the residual cylinder group 33 is in a lean state and the control center of the air-fuel ratio correction amount is determined to be increased.
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