| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of efficiently eliminating the clogging with PM when a recovery control is to be done, which is for recovering the performance of an exhaust gas purifying catalyst such as an NSR catalyst 21, and of precluding an increase of the exhaust pressure loss in an internal combustion engine or a drop of the reliability.SOLUTION: An exhaust emission control device is configured to use a fact that a recovery control (for example, S-poisoning recovery control) of an exhaust gas purifying catalyst causes the catalyst floor temperature to rise owing to the air-fuel ratio turning lean and conduction of a post-injection. When a determination is made that the deposit amount of PM on the front end face of the catalyst has risen beyond a prescribed level, an angle advance is made in the post-injection so that at least a portion of the fuel is combusted in a cylinder. Thus, the temperature of the exhaust gas flowing to the catalyst is increased further, and the PM deposited on the front end face is removed upon oxidation (front end face recovery processing). |
