| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve a PM purification rate and a NOx purification rate per catalyst unit volume while suppressing increase in pressure loss, in an emission control device with catalyst of straight flow structure disposed on the upstream side of exhaust gas of a continuously regenerating DPF. <P>SOLUTION: Each of an upstream catalyst 1 and a downstream catalyst 2 include noble metal and NOx occluding material. A ratio of volume v<SB>2</SB>of the upstream catalyst 2 to a volume v<SB>1</SB>of the downstream catalyst 1 is 1/3 to 2/3, and a ratio of v<SB>1</SB>+v<SB>2</SB>to displacement V of an internal combustion engine is 0.8 to 2.5. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
