| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control system that improves purification performance while suppressing increase in cost. <P>SOLUTION: The exhaust emission control device 50 is provided with: a pre-stage three way catalyst 62 and a post-stage three way catalyst 72 which are provided in the exhaust path 30 of an internal combustion engine 10; a control part 40 for controlling the air/fuel ratio; and an injector 15. The post-stage three way catalyst 72 is formed by laminating a first post-stage catalyst layer 74 containing at least rhodium and a second post-stage catalyst layer 75 containing at least palladium and an alkali metal more than that in the first post-stage catalyst layer 74 on a post-stage support 73. The control part 40 controls the mass of the fuel injected from the injector 15 so that the air/fuel ratio is in a high performance range A, when the temperature of the post-stage three way catalyst 72 is an active temperature. <P>COPYRIGHT: (C)2012,JPO&INPIT |
