Cooling structure for internal combustion engine

摘要

A spacer fitted inside a water jacket of a cylinder block in an internal combustion engine is set so that a space formed between an inner peripheral surface of the spacer and an inner wall surface of the water jacket is smaller than a space formed between an outer peripheral surface of the spacer and an outer wall surface of the water jacket. Accordingly, even if a position of the spacer is shifted in a radial direction, the inner peripheral surface of the spacer comes into abutment on the inner wall surface of the water jacket at first. Thereby, the abutment of the outer peripheral surface of the spacer on the outer wall surface of the water jacket is prevented completely. Therefore, hitting sounds of pistons can be blocked by the space between the outer peripheral surface of the spacer and the outer wall surface of the water jacket.

主权项

1. A cooling structure for an internal combustion engine in which: a spacer is fitted inside a water jacket formed to surround a periphery of a cylinder bore of a cylinder block in the internal combustion engine; and a cooling condition of the cylinder bore is controlled by regulating a flow of cooling water in the water jacket by use of the spacer, wherein
a first space formed between an inner peripheral surface of the spacer and an inner wall surface of the water jacket is smaller than a second space formed between an outer peripheral surface of the spacer and an outer wall surface of the water jacket; and the inner peripheral surface of the spacer is provided with a plurality of protruding parts which protrude toward the inner wall surface of the water jacket that is opposed to the inner peripheral surface of the spacer and a third space between a tip end portion of each of the protruding parts and the inner wall surface of the water jacket is set smaller than said second space, wherein said protruding parts are positioned on an intake side and an exhaust side of the cylinder bore.