| abstract |
An object of the present invention is to suppress the flow of coolant in each water jacket of a cylinder head and a cylinder block when the engine is cold, thereby achieving early combustion stabilization. A water jacket 24 of a cylinder head 22 includes a jacket main body 24a around a combustion chamber, and an exhaust side jacket 24b that communicates with the jacket main body 24a and is provided on the side of the exhaust port opposite to the combustion chamber. In the water jacket 23 of the cylinder block 21, when the engine is cold, circulation means for suppressing the circulation of the cooling water through the jacket body 24a by circulating the cooling water between the water pump 51 and the exhaust side jacket 24b. A jacket spacer for suppressing cooling water from flowing into the jacket body 24a of the cylinder head 22 from the water jacket 23 by suppressing convection of the cooling water. [Selection] Figure 1 |