Abstract: An engine cooling structure includes a cylinder block including a block inner peripheral wall and a block outer peripheral wall that define a water jacket, and a spacer housed in the water jacket. The block outer peripheral wall includes a coolant inlet for introducing a coolant into the water jacket at one end in a cylinder row direction. The spacer includes a peripheral wall surrounding the block inner peripheral wall, and a dividing wall and a distribution wall provided on the peripheral wall. The dividing wall is provided along a circumferential direction of the peripheral wall and protrudes outward from the peripheral wall between a lower end and an upper end of the coolant inlet. The distribution wall includes an upper distribution wall extending upward from the dividing wall and a lower distribution wall extending downward from the dividing wall.

Abstract: An engine cooling structure includes a cylinder block including a block inner peripheral wall that defines a water jacket and a block outer peripheral wall, a spacer housed in the water jacket, and a cooler provided outside the engine body. The spacer includes: a peripheral wall surrounding the block inner peripheral wall; and a dividing wall protruding from the peripheral wall to divide the water jacket into an upper passage and lower passages below the upper passage. A coolant introduced from a coolant inlet into the upper passage passes through an inter-bore part of the block inner peripheral wall. The coolant in the lower passages is introduced into the cooler through a coolant exit.

Abstract: A head-side jacket through which coolant flows is formed in a cylinder head. A main circulation path and a sub circulation path through which coolant fed from a coolant pump respectively circulates are formed. The head-side jacket is separated into an exhaust-port side jacket formed around an exhaust port, and a combustion-chamber-side jacket closer to a combustion chamber than the exhaust-port-side jacket. A heat exchanger is not formed in the main circulation path including the combustion-chamber-side jacket, but is formed in the sub circulation path excluding the combustion-chamber-side jacket and including the exhaust-port-side jacket.

Abstract: An engine cooling structure includes a cylinder block including a block inner peripheral wall that defines a water jacket and a block outer peripheral wall, a spacer housed in the water jacket, and a cooler provided outside the engine body. The spacer includes: a peripheral wall surrounding the block inner peripheral wall; and a dividing wall protruding from the peripheral wall to divide the water jacket into an upper passage and lower passages below the upper passage. A coolant introduced from a coolant inlet into the upper passage passes through an inter-bore part of the block inner peripheral wall. The coolant in the lower passages is introduced into the cooler through a coolant exit.

Abstract: An engine cooling structure includes a cylinder block including a block inner peripheral wall and a block outer peripheral wall that define a water jacket, and a spacer housed in the water jacket. The block outer peripheral wall includes a coolant inlet for introducing a coolant into the water jacket at one end in a cylinder row direction. The spacer includes a peripheral wall surrounding the block inner peripheral wall, and a dividing wall and a distribution wall provided on the peripheral wall. The dividing wall is provided along a circumferential direction of the peripheral wall and protrudes outward from the peripheral wall between a lower end and an upper end of the coolant inlet. The distribution wall includes an upper distribution wall extending upward from the dividing wall and a lower distribution wall extending downward from the dividing wall.

Abstract: A head-side jacket through which coolant flows is formed in a cylinder head. A main circulation path and a sub circulation path through which coolant fed from a coolant pump respectively circulates are formed. The head-side jacket is separated into an exhaust-port side jacket formed around an exhaust port, and a combustion-chamber-side jacket closer to a combustion chamber than the exhaust-port-side jacket. A heat exchanger is not formed in the main circulation path including the combustion-chamber-side jacket, but is formed in the sub circulation path excluding the combustion-chamber-side jacket and including the exhaust-port-side jacket.

Abstract: A cooling structure includes a block-side water jacket formed in a cylinder block, a head-side water jacket formed in a cylinder head, an introducing portion which introduces a cooling liquid from an end of the cylinder block to the block-side water jacket, a discharging portion which discharges a cooling liquid from the other end of the cylinder block to the head-side water jacket, and a spacer member accommodated in the block-side water jacket, and including a peripheral wall which forms an exhaust-side passage and an intake-side passage between a cylinder bore wall and the peripheral wall. The spacer member includes a distribution adjustment mechanism which distributes a cooling liquid introduced to the block-side water jacket between the exhaust-side passage and the intake-side passage.

Abstract: A cooling structure includes a block-side water jacket formed in a cylinder block, a head-side water jacket formed in a cylinder head, an introducing portion which introduces a cooling liquid from an end of the cylinder block to the block-side water jacket, a discharging portion which discharges a cooling liquid from the other end of the cylinder block to the head-side water jacket, and a spacer member accommodated in the block-side water jacket, and including a peripheral wall which forms an exhaust-side passage and an intake-side passage between a cylinder bore wall and the peripheral wall. The spacer member includes a distribution adjustment mechanism which distributes a cooling liquid introduced to the block-side water jacket between the exhaust-side passage and the intake-side passage.