| 摘要 |
PROBLEM TO BE SOLVED: To retain the normal operation of an EGR system for a long period of time by eliminating SOF and soot stuck and deposited in the EGR system. SOLUTION: A traveling distance or fuel consumption is integrated and amounts of SOF and soot stuck to an EGR system 88 are estimated. In the case of judgment that a predetermined amount of SOF is stuck to the EGR device a combustion heater 17 is operated after an engine 1 is stopped, and combustion gas exhausted from the combustion heater 17 is led to flow in the order of a three way valve 97, a branch pipe 95, an intake manifold 21, an EGR passage 90, an EGR valve 92, an exhaust manifold 37 and an exhaust pipe 42. SOF stuck to the EGR system 88 can be burnt and soot can be eliminated by flowing high temperature combustion gas of the combustion heater 17 to the EGR system 88.
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