| 摘要 |
<P>PROBLEM TO BE SOLVED: To lead exhaust gas into an aftertreatment unit while maintaining proper dispersibility regardless of operational conditions of an engine, when leading the exhaust gas into the aftertreatment unit such as a selective reduction catalyst by inverting the exhaust gas. <P>SOLUTION: An exhaust emission control device includes a gas dispersion chamber 7C which envelops an entry-side end surface of the selective reduction catalyst 4 (aftertreatment unit) and which leads the exhaust gas 1 inward via an exhaust gas lead-in port 11 from a direction almost orthogonal to the axial direction of the selective reduction catalyst 4. A mixing pipe 7B (exhaust duct) for leading the exhaust gas 1 into the exhaust gas lead-in port 11 is elongated in the axial direction of the selective reduction catalyst 4, and connected to the exhaust gas lead-in port 11 by being bent back into a hook shape after being temporarily bent in a direction of getting away from the exhaust gas lead-in port 11 at a position immediately before the exhaust gas lead-in port 11. A void part 15 (air leading structure) is formed in the gas dispersion chamber 7C so that a flow of the exhaust gas 1 can be turned back in an arc shape toward the axial center of the selective reduction catalyst 4 in cooperation with an exhaust air guide portion 14. <P>COPYRIGHT: (C)2013,JPO&INPIT |
