| 摘要 |
<P>PROBLEM TO BE SOLVED: To effectively purify PM by a filter catalyst 4 with the usage of NO<SB>2</SB>supplied from NO<SB>x</SB>storage reduction catalyst 3 arranged on an upstream side; and to improve a purification rate of NO<SB>x</SB>during transient traveling. <P>SOLUTION: An upstream side catalyst layer 60 including at least one of Pt and Pd and formed on the upstream side, and a downstream side catalyst layer 70 including at least Rh and formed on the downstream side of the upstream side catalyst layer 60 are formed in the filter catalyst 4. Exhaust gas is sufficiently heated by heat of reaction by the upstream side catalyst layer 60, and thereby, the NO<SB>x</SB>are effectively reduced and purified to N<SB>2</SB>by Rh having high reductive activity in the downstream side catalyst layer 70. <P>COPYRIGHT: (C)2008,JPO&INPIT |
