Patent ID: 7757654
Filing Date: 2010-07-20
Classification: F02F

Abstract:
1. A cylinder head where exhaust ports of adjoining cylinders are gathered together at an exhaust merging portion inside a cylinder head, a partition wall separating the exhaust ports of these adjoining cylinders extends from between these adjoining cylinders to the exhaust merging portion, a head bolt insertion hole is formed inside the partition wall, and an oil passage is formed inside the partition wall between a front end of the partition wall facing the exhaust merging portion and the head bolt insertion hole, wherein a heat insulating layer is formed inside the partition wall between the front end of the partition wall and the oil passage, wherein the oil passage extends about the axis of the heat bolt insertion hole along the outer edges of the head bolt insertion hole boss at said partition wall front end side, and said heat insulating layer extends about the axis of the head bolt insertion hole along the outer edge of the oil passage of said partition wall front end side.