| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an air-fuel ratio control device capable of determining the maximum occlusion quantity of oxygen while avoiding the deterioration of emission. <P>SOLUTION: In determining the maximum occlusion quantity of a first catalyst 53 provided in an exhaust pipe 52, this air-fuel ratio control device sets a target air-fuel ratio upstream of the first catalyst 53 at a prescribed lean air-fuel ratio (or rich air-fuel ratio) when a downstream side air-fuel ratio sensor 67 is inverted from lean to rich (or from rich to lean), determines a feedback correcting quantity to set a detected air-fuel ratio of an upstream side air-fuel ratio sensor 66 to be the target air-fuel ratio, determines a feedforward quantity to set an air-fuel ratio of gas supplied to an internal combustion engine to be lean (or rich), and corrects the feedforward quantity by the feedback correcting quantity to decide a final fuel injection quantity. As a result, even when there is a feedback control delay in the air-fuel ratio, the air-fuel ratio upstream of the first catalyst 53 can be speedily controlled to the target air-fuel ratio. <P>COPYRIGHT: (C)2004,JPO</p> |
