Cylinder head cooling structure for water-cooled multicylinder engine

A cylinder head cooling structure in a water-cooled multicylinder engine, comprising:

• a cylinder block;
• a cylinder head mounted on said cylinder block and cooperating with the cylinder block in forming at least two cylinders arrayed in first direction;
• a water jacket defined in said cylinder head between one side and other side of said cylinder head in a second direction normal to said first direction, said water jacket extending in said first direction above said cylinders;
• a plurality of partitions disposed in said water jacket and between said cylinders and extending in said second direction in said cylinder head;
• said water jacket having a plurality of water jacket compartments defined between said partitions and between outermost ones of said partitions and end walls of said cylinder head in said first direction, said water jacket compartments being positioned above said cylinders, respectively;
• exhaust and intake valves disposed in each of said water jacket compartments above each of said cylinders and in said one side and said other side, respectively, of said cylinder head;
• cooling water inlet ports defined in said cylinder head in communication with said water jacket compartments, respectively, and disposed near said exhaust valves, respectively, and a cooling water outlet port defined in said cylinder head in communication with said water jacket compartments and disposed near said intake valves;
• a plurality of plug insertion tubes disposed in said water jacket compartments above substantially central portions of said cylinders, respectively, and extending from a lower surface to an upper surface of said cylinder head;
• a plurality of walls projecting in said first direction from said partitions and end walls of said cylinder head toward said plug insertion tubes within said water jacket compartments, respectively;
• and
• each of said walls including a projecting portion near said lower surface of said cylinder head and having a relatively small width and a projecting portion near said upper surface of said cylinder head and having a relatively large width.

A cylinder head cooling structure in a water-cooled multicylinder engine, comprising:

• a cylinder block;
• a cylinder head mounted on said cylinder block and cooperating with the cylinder block in forming at least two cylinders;
• a water jacket defined in said cylinder head;
• a plurality of partitions disposed in said water jacket and between said cylinders;
• said water jacket having a plurality of water jacket compartments defined between said partitions and between outermost ones of said partitions and end walls of said cylinder head, said water jacket compartments being positioned above said cylinders, respectively;
• a plurality of plug insertion tubes disposed in said water jacket compartments above said cylinders, respectively, and extending from a lower surface to an upper surface of said cylinder head;
• cooling water inlet ports defined in said cylinder head in communication with said water jacket compartments, respectively, on one side of said plug insertion tubes, and a cooling water outlet port defined in said cylinder head in communication with said water jacket compartments on the other side of said plug insertion tubes;
• a plurality of walls projecting from said partitions and said end walls of said cylinder head toward said plug insertion tubes and defining cooling water passageways between said cooling water inlet ports and said cooling water discharge port;
• and
• said cooling water passageways having a substantially constant width from surfaces of an upper wall of said cylinders and said plug insertion tubes which are to be cooled, as viewed in a direction in which cooling water flows through the cooling water passageways.