| 摘要 |
PROBLEM TO BE SOLVED: To reduce a thermal effect on an EGR valve 31 and to easily optimize the shape of a water jacket 16. SOLUTION: A gas cooler housing 12 is mounted on the front end surface of a cylinder head body, and the water jacket is constituted between the housing and the jacket. An EGR gas passage 18 is formed in the inner part thereof, and the EGR valve 31 is installed to a valve housing chamber 22 in the middle. An EGR gas inlet 20 at one end is directly connected to the EGR gas passage of an exhaust manifold, and an EGR gas outlet 21 at the other end is directly connected to the EGR gas passage of an intake manifold. The EGR gas passage 18 and the valve housing chamber 22 are surrounded by the water jacket within the gas cooler housing 12, and comprise a rib-like heat sink so as to increase a contact area with cooling water carried in through a cooling water inlet 41. Thus, the EGR gas can be surely cooled to avoid the temperature rise of a drive motor part 35. |
