| 摘要 |
PROBLEM TO BE SOLVED: To provide an EGR system which suppresses the occurrence of a partial boil of cooling water, and can reduce a drive loss of a water pump.SOLUTION: An EGR system 50 comprises a cooling water passage 80 which has: a high-pressure side cooling water passage 81 which makes cooling water W flow into a high-pressure side EGR cooler 63; a low-pressure side cooling water passage 83 which is arranged at an upstream side of the high-pressure side cooling water passage 81, and makes the cooling water W flow into a low-pressure side EGR cooler 73; a low-pressure side bypass passage 85 which bypasses the low-pressure side cooling water passage 83; and a first changeover valve V1 which switches a bypass so that the cooling water W is bypassed to a low-pressure side bypass passage 85 or not. The EGR system 50 comprises a water pump P which pressurizes the cooling water W passing through the cooling water passage 80, and an ECU 90 which controls the first changeover valve V1. The ECU 90 controls the first changeover valve V1 under a non-operation condition of the low-pressure side EGR system 70 so that at least a part of the cooling water W is bypassed to the low-pressure side bypass passage 85.SELECTED DRAWING: Figure 1 |
