| 摘要 |
PROBLEM TO BE SOLVED: To prevent dew condensation in an EGR cooler so as to improve durability by providing an EGR pipe with an EGR cooler and an EGR valve, connecting an intake branch pipe connected to an intake pipe downstream from a supercharger to the upstream of the EGR cooler, thereby supplying diluted EGR gas to the intake side. SOLUTION: An EGR pipe 4, which has one end connected to an exhaust pipe 2 and the other end connected to an intake pipe 3a upstream from a compressor 12b of a supercharger 12, is provided with an EGR cooler 6 and an EGR valve 8. An intake branch pipe 5, one end of which is connected to an intake pipe 3b downstream from the compressor 12b of the supercharger 12, is connected to the upstream side of the EGR cooler 6. The intake branch pipe 5 is provided with a first throttle valve 9 and a second throttle valve 10 is provided on the EGR pipe 4a upstream from the connecting part 7 of the intake branch pipe 5. By adjusting the valve opening of the above valves, backflow of EGR gas in the EGR pipe 4 and inflow of EGR gas into the intake branch pipe 5 are prevented, and at the same time, intake air is mixed in EGR gas to be diluted. |
