| 摘要 |
PROBLEM TO BE SOLVED: To provide an air/fuel ratio control device for an internal combustion engine having further excellent exhaust emission control characteristics by effectively utilizing the oxygen storing operation of an exhaust emission control catalyst. SOLUTION: The air/fuel control device for the internal combustion engine comprises oxygen storing amount estimating means 18 for estimating the oxygen storing amount of the exhaust emission control catalyst 19 disposed in an exhaust passage 7 in the internal combustion engine 1 in accordance with the history of a oxygen storing/releasing amount, downstream exhaust air/fuel ratio detecting means 26 disposed downstream from the exhaust emission control catalyst 19, maximum oxygen storing amount estimating means 18 for estimating the maximum oxygen storing amount in accordance with an estimated value for the oxygen storing amount in case of the detected exhaust air/fuel ratio being a preset air/fuel ratio, and air/fuel ratio target value setting means 18 for setting a target value for a controlled air/fuel ratio in accordance with the estimated maximum oxygen storing amount estimated value. The oxygen storing amount estimating means 18 estimates the oxygen storing amount in accordance with the amount of a fuel to be supplied into a cylinder, predicted by a fuel behavior model considering the fuel deposited on the inner face of an inlet passage 4. |
