| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device of a diesel engine for efficiently controlling NOx with a small amount of HC over a wide range of temperature in the diesel engine in which a NOx-control catalyst for selective catalytic reduction is used. <P>SOLUTION: The NOx-control catalyst (40) for selective catalytic reduction is composed of a low-temperature type NOx-control catalyst (42) and an intermediate-temperature type NOx-control catalyst (41). In the low-temperature type NOx-control catalyst (42), a noble metal is applied, which has a high oxidative performance at around a 1st prescribed temperature, and a peak reductive performance on the side of lower temperature than the 1st prescribed temperature. In the intermediate-temperature type NOx-control catalyst (41), another noble metal is applied, which has a high oxidative performance at around a 2nd prescribed temperature higher than the 1st prescribed temperature, and a peak reductive performance on the lower-temperature side than the 2nd prescribed temperature, and on a higher temperature side than the 1st prescribed temperature. The catalyst (41) is arranged in series upstream of the catalyst (42). <P>COPYRIGHT: (C)2005,JPO&NCIPI |
