| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an air/fuel ratio control device for an internal combustion engine capable of improving the exhaust gas purifying efficiency of an exhaust gas purifying catalyst by estimating the exhaust amount of a specified component in exhaust gas flowing out of the exhaust gas purifying catalyst (or a representative value representing the condition of exhaust gas) and controlling an air/fuel ratio in accordance with the estimated value. Ž<P>SOLUTION: The air/fuel ratio control device estimates, on the basis of an exhaust air/fuel ratio of exhaust gas flowing into the exhaust purifying catalyst 19 disposed in an exhaust passage 7 of an engine 1, at least one estimation value related to a component increased in the discharge amount during a rich air/fuel ratio, and at least one estimation value related to a component increased in the discharge amount during a lean air/fuel ratio, being at least one representative value indicating the discharge amount of at least one specific component contained in exhaust gas flowing out of the exhaust gas purifying catalyst 19 or a state of the exhaust gas that is flowing out, sets a target state for each estimation value, and controls the air/fuel ratio so that each estimation value reaches its target state. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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