| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem in an exhaust emission control device using HC adsorbent that HC which is discharged after starting cannot be sufficiently purified because HC desorption is started from the HC absorbent before a three-way catalyst reaches an activation temperature after cold starting of an engine. <P>SOLUTION: The three-way catalyst (carrier) 33 and an HC trap catalyst (carrier 21) are adjacently arranged so that the former is located on the upstream side and the latter on the downstream side, and a slit 22 is formed on the carrier of the HC trap catalyst so as to cross its cell. Since the slit has the effect of interrupting the heat transfer in the carrier around it, the heat transfer to the downstream side from the slit is suppressed, and the temperature rise and HC desorption timing are delayed as the whole catalytic carrier. Since the temperature of the catalytic metal is raised during it to increase the transfer ratio, the processing efficiency in the desorption of HC is improved, and the transfer efficiency of the three-way catalyst on the upstream side is also improved. <P>COPYRIGHT: (C)2004,JPO |
