| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an exhaust emission control system for an engine having a diesel particulate filter(DPF) with which generation of white smoke is prevented when starting or gunning after engine idling. SOLUTION: An exhaust passage 4 of an engine 1 is branched off in branched passages 21, 22 by way of a switch valve 23. These branched passages 21, 22 are provided with diesel particulate filters (DPFs) 25, 26 having heating means 25h, 26h and filters 25f, 26f for trapping particulate. They are also provided with idling detection means for determining whether or not the engine operation is in an idling state, and a controller 3 for controlling the heating means 25h, 26h and switching the switch valve 23. Every time the idling state continues for more than a predetermined judging time Tc1, the switch valve 23 is switched to change between the DPFs 25 and 26 to pass the exhaust gas G. Then, the DPF 25 or 26 in which flow of the exhaust gas G is interrupted is heated by the corresponding heating means 25h or 26h.</p> |
