| 摘要 |
PROBLEM TO BE SOLVED: To provide technology for suppressing a trouble of increasing the pressure drop of a low pressure EGR device or lowering the performance while preventing the residence of unburnt fuel or condensed water in the low pressure EGR device in spite of an increase in the discharge amount of the unburnt fuel with the low pressure EGR device carrying out great-amount EGR or in the production amount of the condensed water in the low pressure EGR device. SOLUTION: This exhaust emission control system comprises a compressor 6 for supplying compressed intake air to an internal combustion engine 1, an EGR passage 15 for recirculating part of exhaust gas flowing in an exhaust passage 11 to an intake passage 3 on the upstream side of the compressor 6, and a bypass passage 19 for introducing part of the intake air compressed by the compressor 6 to the EGR passage 15 on the downstream side of an EGR cooler 16. In the operating condition of the internal combustion engine 1 when stopping EGR, the intake air introduced via the bypass passage 19 to the EGR passage 15 flows from the downstream side of the EGR passage 15 back to the upstream side. Thereby, unburnt fuel or condensed water is blown off and removed from the EGR passage 15. COPYRIGHT: (C)2007,JPO&INPIT
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