CYLINDER BLOCK FOR INTERNAL COMBUSTION ENGINE

PURPOSE: To reduce the deformation of a cylinder liner, and to prevent the seizure of a piston by forming a rib, which connects the cylinder liner part and a side wall part, so that it is arranged in the height direction upper than a central part of the length of the cylinder liner and that it is arranged in the circumferential direction at the intermediate part of a head bolt. CONSTITUTION: A cylinder block C of an internal combustion engine is integrally formed with a cylinder liner 5 so as to form the semi-open deck structure. A rib 7 for connecting the cylinder liner part and the side wall part is formed so that it is arranged in the height direction upper than the central part of the length direction of the cylinder linear 5 and that is arranged in the circumferential direction at the intermediate part of a head bolt hole 4. As a result, when a cylinder head is placed and a head bolt is screwed with the head bolt hole 4 for fastening, the bolt fastening force for pulling upward is applied to the part of to head bolt hole 4, and as the reaction force thereof, the gasket surface pressure is generated as a load for pushing the cylinder block downward. The part of the cylinder block 5 is deformed, but the deformation thereof is reduced by the rib 7.