| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve oil cooling efficiency and protection property around a fastening bolt hole.SOLUTION: A cylinder head structure includes an exhaust gas collection part 23b and a water jacket 30 formed inside a cylinder head, a plurality of fastening bolt holes 15, and an oil hole 18 formed passing through the bottom of a valve chest. The water jacket 30 has a main route 31 provided above cylinders, a port route 32 provided at least either above or below the exhaust gas collection part 23b, and a curved part 34 provided on the cooling water downstream side of a joint part 30c where the main route 31 and the port route 32 are joined on the other side. The oil hole 18 is provided on the further cooling water upstream side of the port route 32 than the fastening bolt hole 15r while neighboring the fastening bolt hole 15r located closest to the joint part 30c. The curved part 34 is provided extending from the cooling water downstream side of the joint part 30c toward the oil hole 18 while being curved around the fastening bolt hole 15r.</p> |
