| 摘要 |
PROBLEM TO BE SOLVED: To improve the recovery properties of a catalyst from S poisoning of a catalyst, in an exhaust emission control device provided in the exhaust passage of an engine with a lean NOx catalyst to absorb NOx and a sulfur content when oxygen concentration in exhaust gas is high and discharge NOx when oxygen concentration is decreased. SOLUTION: In this device, at least one kind selected from K, Sr, Mg, and La and Ba are employed as an element of which the NOx adsorbent of a catalyst 25 consists. Recovery from S poisoning is executed in a way that when it is decided by a sulfur absorption deciding means (a) that a content is excessively absorbed in an NOx absorbent, oxygen concentration in exhaust gas is decreased by a sulfur desorption means (b) and the temperature of the NOx absorbent is increased. |
