| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To improve accuracy for detecting failure of a secondary air introduction mechanism introducing secondary air in an exhaust passage for the purpose of activating a catalyst quickly. <P>SOLUTION: A fuel injection volume calculated and supplied on the basis of various operation parameters of an internal combustion engine 10 is reduced for correcting an air-fuel ratio immediately after the secondary air is stopped by a secondary air introduction mechanism 30.When a result detected by an A/F sensor 24 is leaner than a predetermined value, an introducing condition is still kept though the secondary air from the secondary air introduction mechanism 30 is made in a stop condition, so that the secondary air introduction mechanism 30 is judged as fail. Failure of the secondary air introduction mechanism 30 is judged using an A/F sensor value from the A/F sensor 24, so as to improve accuracy for detecting failures. <P>COPYRIGHT: (C)2004,JPO</p> |
