| 摘要 |
<P>PROBLEM TO BE SOLVED: To avoid discharge of NOx in the atmosphere, even if the NOx conversion rate of a reduction catalyst decreases, when regenerating a filter for burning and removing an exhaust particulate collected by the filter, when arranging a particulate filter and an NOx reduction catalyst in this order from the upstream side in an exhaust passage. <P>SOLUTION: In the exhaust passage 3 of an engine 1, an SCR catalyst 15 for reducing NOx in exhaust gas by receiving supply of urea by a urea water injection nozzle 13, is arranged on the downstream side of the particulate filter 12 for collecting the exhaust particulate in the exhaust gas. When regenerating the filter 12, a supply quantity of the urea by the urea water injection nozzle 13 is increased more than when the filter is not regenerated. <P>COPYRIGHT: (C)2009,JPO&INPIT |
