| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of eliminating sulfur poisoning while inhibiting thermal deterioration of an exhaust emission control catalyst, of discharging NOx stored in NOx storage reduction catalyst, and of improving NOx conversion by selective reduction catalyst using ammonia formed during reduction. <P>SOLUTION: The exhaust emission control device includes an SOx trap catalyst that can capture SOx contained in exhaust gas and that is disposed in an exhaust passage upstream of an NOx storage reduction catalyst. The exhaust emission control device further includes a selective reduction catalyst that selectively reduces NOx using ammonia, is disposed downstream of the NOx storage reduction catalyst. The exhaust emission control device executes secondary exhaust emission control action inhibiting storage of SOx to the NOx storage reduction catalyst by the SOx trap catalyst, discharging NOx stored in the NOx storage reduction catalyst by temporarily operating an engine at rich air-fuel ratio, and reducing NOx by the selective reduction catalyst with using ammonia formed during reduction. <P>COPYRIGHT: (C)2009,JPO&INPIT |
