| 摘要 |
PROBLEM TO BE SOLVED: To improve combustion stability by providing cooling water passages independently for a cylinder body and a cylinder head and communicating the cooling water passage for the cylinder head to the lower reaches side of the cooling water path for cylinder body. SOLUTION: Cooling water passages in an engine 12 are formed independently for a cylinder body 20 and a cylinder head 21. The cooling water passage for the cylinder body 20 is communicated with a PCV and the cylinder body 20 is cooled at first by the engine cooling water flowing from the PCV to an engine 12 side. The cooling water passage for the cylinder body 20 is so formed that the engine cooling water flowing from a cooling water inlet under the cylinder body flows upward while cooling respective cylinders. It is communicated with a cooling water passage for the cylinder head 21 via a thermostat 46 provided at the top of the cylinder body. The cooling water passage for the cylinder head 21 thus cools a suction port and an exhaust port by the engine cooling water flowing from the cooling water inlet in the top of the cylinder head. |
