TW360745B - Water cooling structure for two cycle engine with exhaust control valve - Google Patents

Abstract

To provide a water jacket which can cool a bearing part of an exhaust open/close valve efficiently while keeping inside an exhaust cylinder at a high temperature, in a two cycle engine equipped with the exhaust switch valve in an exhaust cylinder. An exhaust cylinder 3 is provided integrally with a cylinder block 1 and a bearing part for supporting an exhaust open/close valve 9 is projected by provided in both end parts of the exhaust cylinder 3 and a bearing cooling part 10 is provided in the bearing part. A C-shaped bearing water jacket 13 is provided on one the of bearing parts 7 and a water passage 11 from a divided flow part 4a of a cylinder block water jacket 4 is communicated with its lower end. A C-shape bearing water jacket and a water passage are provided on the other bearing and upper ends of both bearing water jackets are communicated by a communicating path 15. Cooling water goes out of a converging point through the divided flow part 4a, the bearing water jacket 13 and the communicating path 15. 16 represents an inner ring hole and projected part of a sand core for the bearing cooling part 10 passes the hole and supported at outside.