| 摘要 |
PROBLEM TO BE SOLVED: To improve cooling efficiency for exhaust gas by a method wherein the length of a flow passage for cooling water is increased, in a cooling device for EGR to perform cooling of exhaust gas returned from an exhaust system to an intake system. SOLUTION: This device is arranged in an EGR piping 16 which takes out a part of exhaust gas from the exhaust passage 14 of an engine 11 and recirculates it to an intake passage 13, and the exhaust gas flowing through the EGR piping 16 is cooled by cooling water. In this case, an outer cylinder 21 is disposed in a manner to cover an inner cylinder 20 connected to the EGR piping 16 and cooling water is caused to flow through a space between the inner and outer cylinders 20 and 21. Further, a throttle part 22 to substantially increase the length of a flow passage for cooling water is arranged between the inner and outer cylinders 20 and 21. |
