Structure of a cylinder assembly for an internal combustion engine

Abstract

A structure of a cylinder assembly of an internal combustion engine has a coolant circulating system for cooling the cylinder assembly while the engine is driving. The cylinder assembly generally comprises a cylinder block formed therein a plurality of engine cylinder in line, and a cylinder head sealingly mounted on the cylinder block. The coolant circulating system comprises a coolant chamber formed within the cylinder block so that it surrounds substantial part of each engine cylinder, a return passage formed in the cylinder head. The coolant chamber communicates with the return passage through a plurality of vertical passages. Adjacent the top of the vertical passage, there is provided with a projecting portion inwardly projecting thereto. A sloped passage is formed within a partition disposed between each of adjacent engine cylinder. The upper end of the sloped passage is opened at the projecting portion at right angle to the planar surface of the projecting portion. By forming the projecting portion within the vertical passage and forming the sloped passage extending therefrom at right angle, it makes easy to form the sloped passage within the partition. Further, by forming the sloped passage as the manner mentioned above, the cylinder assembly is easily prevented from leakage of coolant and/or air/fuel mixture discharged to the engine cylinder.