| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To simplify a control configuration and appropriate responsiveness and exhaust emission. <P>SOLUTION: An upstream side catalyst 15 and a downstream side catalyst 16 are arranged in the exhaust pipe 13 of an engine 10. First, second, and third air-fuel ratio sensors 21-23 are disposed on the upstream side of the upstream side catalyst 15, between the upstream side catalyst 15 and the downstream side catalyst 16, and on the downstream side of the downstream side catalyst 16, respectively. An engine ECU 30 so performs F/B control that an actual air-fuel ratio matches a target air-fuel ratio according to the output value of a first air-fuel ratio sensor 21. A sub F/B parameter corresponding to the internal air-fuel ratio of the downstream side catalyst 16 is calculated according to the output value of each of the second and third air-fuel ratio sensors 22, 23. A control parameter in the F/B control is corrected by using the sub F/B parameter. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
