| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an EGR device capable of avoiding coking occurring in a heat exchange part of an EGR cooler caused by fuel addition in an engine side. <P>SOLUTION: A diesel engine 1 provided with a front stage oxidation catalyst 14 and a particulate filter 13 as exhaust emission control catalyst requiring fuel addition in a middle of an exhaust pipe 11 and performing fuel addition to an exhaust gas 9 by adding post injection at a time of fuel injection to each cylinder 8, is provided with an EGR line 15 returning part of the exhaust gas 9 drawn out from exhaust side to an intake side via an EGR cooler 16, a bypass line 21 returning part of the exhaust gas 9 drawn out from exhaust side to an intake side with bypassing the EGR cooler 16, an EGR oxidation catalyst 22 provided in the bypass line 21 to perform oxidation treatment of unburned fuel component in the exhaust gas 9, and a change over valve 23 as a flow passage change over means selecting one of the EGR line 15 and the bypass line 21 and suitably distributing the exhaust gas 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
