CYLINDER BLOCK AND INTERNAL COMBUSTION ENGINE

摘要

A cylinder block produced by casting has a cylinder bore wall portion, a water jacket groove provided in the outer periphery of the cylinder bore wall portion, and a water jacket outer wall portion delimiting the cylinder bore wall portion and the water jacket groove. The water jacket groove has a shallow groove portion whereof the groove depth becomes shallower with increasing proximity to the end of the cylinder bore wall portion. If "down" is defined as the direction of increasing depth into the groove, the portion of the cylinder bore wall portion where the shallow groove portion is located has a second outer wall surface facing the water jacket groove and a third outer wall surface that is downward of the groove bottom of the shallow groove portion and constitutes the outer wall surface of the cylinder block. The third outer wall surface facing the cylinder bore is recessed.