Patent ID: 8347845

Claim:
An engine, comprising: a crankcase; a crankshaft extending between front and rear walls of the crankcase; and an engine oil filter system wherein the engine oil filter system includes, an oil filter adapted to filter lubricating oil supplied to the engine from an oil pump, and a filter-attachment base joined to one side surface of the engine at a base-attachment surface thereof, wherein the engine comprises a bearing wall which forms a part of the crankcase but is a separate component from a main part of the crankcase, the bearing wall forming the rear end wall of the crankcase and being located rearwardly of the main part of the crankcase, wherein the oil filter is attached to the filter-attachment base at a filter-attachment surface thereof, wherein the base-attachment surface for joining the filter-attachment base is formed in the bearing wall, wherein the filter-attachment surface is substantially at right angles to the base-attachment surface and faces the front side of the engine, wherein the engine oil filer system further comprises, an oil cooler formed integrally with the filter-attachment base, the oil cooler being adapted to cool down the lubricating oil transferred between the engine and the oil filter, and wherein the oil cooler includes, a cooler tower formed integrally with the filter-arrangement base so as to protrude from one side of the filter-attachment base in a direction different from that in which the oil filter extends, a bent oil passage provided inside the cooler tower so that the oil transferred between the engine and the oil filter passes through the bent oil passage, and a large number of radiator fins provided in a protruding manner on an outer periphery of the cooler tower, and wherein the engine comprises a cooling fan fixed to one end portion of the crankshaft, the end portion protruding out from the front wall of the crankcase, and wherein the radiator fins are oriented in parallel with a direction in which the cooling air sent with pressure from the cooling fan flows.