| 摘要 |
<P>PROBLEM TO BE SOLVED: To promote decomposition reaction from a urea solution to ammonia, and as a result, to appropriately control emission of NOx. <P>SOLUTION: A DPF 12 and an SCR catalyst 13 are arranged in an exhaust pipe 11, and a urea solution addition valve 15 for supplying urea solution into the exhaust pipe 11 is provided between the DPF 12 and the SCR catalyst 13. A water addition valve 41 is provided between the urea solution addition valve 15 and the SCR catalyst 13 in the exhaust pipe 11, and water is supplied into the exhaust pipe 11 by the water addition valve 41. In such a case, urea decomposition reaction from urea solution to ammonia is promoted in the exhaust pipe 11 by the water supplied from the water addition valve 41, and NOx emission control performance in the SCR catalyst 13 can be thereby maintained. <P>COPYRIGHT: (C)2010,JPO&INPIT |
