A cylinder block assembly may include a cylinder block, a cylinder body disposed in the cylinder block, with a plurality of cylinder bores formed in the cylinder body, a fluid jacket, which is formed between an inner circumferential surface of the cylinder block and an outer circumferential surface of the cylinder body, and through which coolant flows, and a block insert disposed in the water jacket and configured to guide a flow of coolant, wherein the cylinder block may include a second block coolant outlet, which is formed at a second side in a surface of an exhaust side of the cylinder block, and through which the coolant in the water jacket is discharged, and wherein the exhaust side may include a side at which combustion gas is exhausted out of the cylinder body.

A cylinder block for an internal combustion engine includes a metal section and a resin section. The metal section includes: a cylinder liner; head bolt female screw portions that are screwed onto male screw portions of head bolts that fasten the cylinder block and a cylinder head; crank cap bolt female screw portions that are screwed onto male screw portions of crank cap bolts that fasten the cylinder block and crank caps and columnar portions that connect the head bolt female screw portions; and the crank cap bolt female screw portions. The cylinder liner and the columnar portions are integrated with each other.

A cylinder block for an internal combustion engine includes a metal section and a resin section. The metal section includes: a cylinder liner; head bolt female screw portions that are screwed onto male screw portions of head bolts that fasten the cylinder block and a cylinder head; crank cap bolt female screw portions that are screwed onto male screw portions of crank cap bolts that fasten the cylinder block and crank caps and columnar portions that connect the head bolt female screw portions; and the crank cap bolt female screw portions. The cylinder liner and the columnar portions are integrated with each other.

A water jacket spacer is provided that ensures that a cylinder bore wall has a uniform temperature. When a contact member that comes in contact with the all surface of a groove-like coolant passage is provided to either or both of the inner wall side and the outer wall side of the water jacket spacer along the longitudinal direction of the water jacket spacer to divide the groove-like coolant passage into an upper part and a lower part, it is possible to separately control the flow rate of the coolant that flows through the upper passage of the groove-like coolant passage, and the flow rate of the coolant that flows through the lower passage of the groove-like coolant passage, and separately adjust the degree of cooling with respect to the upper part and the lower part of the cylinder bore wall.

A water jacket spacer is provided that ensures that a cylinder bore wall has a uniform temperature. When a contact member that comes in contact with the all surface of a groove-like coolant passage is provided to either or both of the inner wall side and the outer wall side of the water jacket spacer along the longitudinal direction of the water jacket spacer to divide the groove-like coolant passage into an upper part and a lower part, it is possible to separately control the flow rate of the coolant that flows through the upper passage of the groove-like coolant passage, and the flow rate of the coolant that flows through the lower passage of the groove-like coolant passage, and separately adjust the degree of cooling with respect to the upper part and the lower part of the cylinder bore wall.

There is provided a novel regulating member that ensures easy manufacturing and does not adversely affect cooling water and environment. A spacer 6 is inserted from an opening 30 of a cooling water flow passage 3 into the cooling water flow passage 3 to be disposed. The cooling water flow passage 3 is disposed in a cylinder block 1 in an internal combustion engine. The spacer 6 includes a supporting member 7 with rigidity formed into a shape configured to be disposed in the cooling water flow passage 3 and a regulating portion 8 supported by the supporting member 7. The regulating portion 8 regulates a flow of cooling water. The regulating portion 8 includes a cellulose-based sponge 81. The cellulose-based sponge 81 is restorable from a compressed state through a contact with the cooling water w.

There is provided a novel regulating member that ensures easy manufacturing and does not adversely affect cooling water and environment. A spacer 6 is inserted from an opening 30 of a cooling water flow passage 3 into the cooling water flow passage 3 to be disposed. The cooling water flow passage 3 is disposed in a cylinder block 1 in an internal combustion engine. The spacer 6 includes a supporting member 7 with rigidity formed into a shape configured to be disposed in the cooling water flow passage 3 and a regulating portion 8 supported by the supporting member 7. The regulating portion 8 regulates a flow of cooling water. The regulating portion 8 includes a cellulose-based sponge 81. The cellulose-based sponge 81 is restorable from a compressed state through a contact with the cooling water w.

A water jacket coolant passage division member includes: a partition member that has a planar shape that conforms to a groove-like coolant passage provided to a cylinder block that is provided to an internal combustion engine; an inner-side rubber member that is provided to an inner side of the partition member, and comes in contact with a cylinder bore-side wall surface of the groove-like coolant passage; and an outer-side rubber member that is provided to an outer side of the partition member, and comes in contact with an outer wall surface of the groove-like coolant passage. An internal combustion engine in which a cylinder bore wall has a uniform temperature can be provided by utilizing the water jacket coolant passage division member.

A water jacket coolant passage division member includes: a partition member that has a planar shape that conforms to a groove-like coolant passage provided to a cylinder block that is provided to an internal combustion engine; an inner-side rubber member that is provided to an inner side of the partition member, and comes in contact with a cylinder bore-side wall surface of the groove-like coolant passage; and an outer-side rubber member that is provided to an outer side of the partition member, and comes in contact with an outer wall surface of the groove-like coolant passage. An internal combustion engine in which a cylinder bore wall has a uniform temperature can be provided by utilizing the water jacket coolant passage division member.

An engine cooler capable of suppressing a piston slap sound is provided. The engine cooler includes a cylinder block including a cylinder barrel and a water jacket, and a spacer stored in the water jacket, the water jacket surrounds the cylinder barrel, and the spacer encloses the cylinder barrel. Given that a width direction of the cylinder block is a lateral direction, a pressed member is pressed between the cylinder barrel and the spacer on lateral sides of the cylinder barrel, and a lower end of the pressed member is disposed above a lower end of each of right and left skirts of a piston located at a top dead center.