| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control system with excellent HC purifying efficiency, especially upon starting of an engine. <P>SOLUTION: The exhaust emission control system is composed to have at least two exhaust emission control catalysts having an HC adsorption function and being supported by an integrated structure-type carrier positioned in series on an exhaust emission flow passage. While the HC adsorption purifying catalyst positioned upstream of the exhaust emission flow passage includes at least platinum as a purifying component, the HC adsorption purifying catalyst positioned downstream includes noble metals such as platinum, palladium, and rhodium. An amount of platinum included in the upstream HC adsorption purifying catalyst is larger than that included in the downstream HC adsorption purifying catalyst. <P>COPYRIGHT: (C)2004,JPO |
