| 摘要 |
<P>PROBLEM TO BE SOLVED: To more accurately detect a temperature of an exhaust emission control catalyst by calculating a temperature of the exhaust emission control catalyst based on a rich air fuel ratio difference calculated by using an air fuel ratio of exhaust gas flowing out of the exhaust emission control catalyst. <P>SOLUTION: An internal combustion engine is equipped with the exhaust emission control catalyst 52 in an exhaust gas passage 50. The engine is provided with an upstream side exhaust air fuel ratio detection means 53 detecting an air fuel ratio of exhaust gas flowing into the exhaust emission control catalyst, and a downstream side exhaust air fuel ratio detection means 54 detecting an air fuel ratio of exhaust gas flowing out of the exhaust emission control catalyst. The air fuel ratio of the exhaust gas flowing out of the exhaust emission control catalyst is detected by detecting a component concentration in the exhaust gas flowing out of the exhaust emission control catalyst by the downstream side air fuel ratio detection means. When the air fuel ratio of the exhaust gas flowing into the exhaust emission control catalyst is richer than a theoretical air fuel ratio, a difference between the air fuel ratio of exhaust gas detected by the upstream side exhaust gas air fuel ratio detection means and the air fuel ratio of exhaust gas detected by the downstream side exhaust gas air fuel ratio detection means is calculated as the rich air fuel ratio difference. A temperature of the exhaust emission control catalyst is calculated based on the rich air fuel ratio difference. <P>COPYRIGHT: (C)2011,JPO&INPIT |
