Abstract: An internal combustion engine body includes a cylinder block including a plurality of cylinders, a first water jacket, and a second water jacket, and a cylinder head including an in-head water jacket. The in-head water jacket includes an intake-side flow passage. The cylinder block and the cylinder head are provided such that a flow rate of coolant that directly flows into the intake-side flow passage after flowing into the first water jacket is higher than a flow rate of coolant directly flows into any region other than the intake-side flow passage after flowing into the first water jacket.

Abstract: An internal combustion engine body includes a cylinder block including a plurality of cylinders, a first water jacket, and a second water jacket, and a cylinder head including an in-head water jacket. The in-head water jacket includes an intake-side flow passage. The cylinder block and the cylinder head are provided such that a flow rate of coolant that directly flows into the intake-side flow passage after flowing into the first water jacket is higher than a flow rate of coolant directly flows into any region other than the intake-side flow passage after flowing into the first water jacket.

Abstract: A cooling apparatus of an internal combustion engine according to the invention comprises a first passage formed in the cylinder block, through which the cooling medium flows for cooling between-bores portions, a second passage formed in the cylinder block, through which the cooling medium flows for cooling a bore-surrounding portion, and a cooling medium supplying mechanism for supplying the cooling medium to the first and second passages such that ability of the cooling medium for cooling the between-bore portions, is different from the ability of the cooling medium for cooling the bore-surrounding portion.