| 摘要 |
PROBLEM TO BE SOLVED: To suppress the recovery of an occlusion reduction NOx catalyst from sulfur poisoning beyond necessity.SOLUTION: An internal combustion engine exhaust emission control device comprises: a NOx catalyst occluding NOx; and a control unit implementing a sulfur poisoning recovery control if an amount of a sulfur component occluded in the NOx catalyst is not smaller than a predetermined value that is a value relating to a demanded occluded amount of the sulfur component and a predetermined sulfur poisoning recovery condition is satisfied, and the control unit finishes the sulfur poisoning recovery control if the amount of the sulfur component occluded in the NOx catalyst is not greater than a threshold that is a value not greater than the predetermined amount after starting the sulfur poisoning recovery control, the threshold being set greater in the sulfur poisoning recovery control at a present time if the quantity of the sulfur component occluded in the NOx catalyst is smaller at the time of starting the sulfur poisoning recovery control.SELECTED DRAWING: Figure 6 |
