Abstract: A cylinder head includes a water jacket. The water jacket includes multiple coolant spaces between combustion chambers adjacent. The multiple coolant spaces include a high-pressure space having relatively high internal pressures and a low-pressure space having relatively low internal pressures. The high-pressure space and the low-pressure space are alternately arranged with each other. The water jacket includes a first lateral passage passing through the low-pressure space and extending in the lateral direction of the cylinder head, and a communication passage passing between an intake valve hole and an exhaust valve hole, and allowing the high-pressure space and the low-pressure space to communicate with each other. A coolant outlet is connected to the first lateral passage. The coolant inlet is connected to the communication passage or the high-pressure space.

Abstract: A cylinder head includes a water jacket. The water jacket includes multiple coolant spaces between combustion chambers adjacent. The multiple coolant spaces include a high-pressure space having relatively high internal pressures and a low-pressure space having relatively low internal pressures. The high-pressure space and the low-pressure space are alternately arranged with each other. The water jacket includes a first lateral passage passing through the low-pressure space and extending in the lateral direction of the cylinder head, and a communication passage passing between an intake valve hole and an exhaust valve hole, and allowing the high-pressure space and the low-pressure space to communicate with each other. A coolant outlet is connected to the first lateral passage. The coolant inlet is connected to the communication passage or the high-pressure space.