| 摘要 |
PROBLEM TO BE SOLVED: To clean a heat exchanger of an EGR cooler.SOLUTION: An EGR cooler 344 includes: a heat exchanger 344A through which an EGR gas passes; a casing 344B including the heat exchanger; and a first bypass passage 344C and a second bypass passage 344D which bypass the heat exchanger 344A. First butterfly valves 344E for opening and closing openings and first actuators 344F are arranged at both ends of the first bypass passage 344C and the second bypass passage 344D. Furthermore, second butterfly valves 344G for opening and closing internal passages of the casing 344B and second actuators 344H are arranged between both the ends of the first bypass passage 344C and both the ends of the second bypass passage 344D. Then, by making the EGR gas pass through the first bypass passage 344C, the heat exchanger 344A and the second bypass passage 344D, the heat exchanger 344A is back-washed by the EGR gas, and cleaned. |
