COOLING SYSTEM FOR MULTI-CYLINDER ENGINE

摘要

In a cooling system for a multi-cylinder engine, a main gallery is provided around a plurality of cylinder bores upstream of a block-side coolant jacket and an upstream coolant gallery is provided between the block-side coolant jacket and the main coolant gallery around the cylinder bores. The coolant galleries communicate with each other through constricted communication passages provided around the cylinder bore, and the upstream coolant gallery further communicates with an upstream end of the block-side coolant jacket. The cooling system further includes a block-side flange-surrounding coolant gallery in the cylinder block surrounding the outer periphery of the outward flange of each cylinder liner, and a plurality of dispensing passages connecting the block-side coolant jacket and the flangesurrounding coolant gallery. A jacket sidewall is disposed in the cylinder head inside at least one of the outside wall thereof located on opposite sides of the crank-shaft axis to define a head-side coolant jacket. Thereby heated portions of the cylinder block and outward flanges of the cylinder liners are uniformly and efficiently cooled. In addition, the headside coolant jacket is provided only in a relatively narrow section required to be cooled, to enable a high flow speed of the coolant flowing in the head-side coolant jacket.