OIL PATH STRUCTURE FOR AIR OIL COOLED INTERNAL COMBUSTION ENGINE

摘要

An oil path (68A) for lubrication is provided in the cylinder head (13) of an air oil cooled internal combustion engine and a head side oil path (7) for cooling is branched from the path (68A). The cylinder block (12) is provided with an oil return path (9) for conducting oil which flows from the oil path (7) for cooling to the crankcase (10). The oil path (7) is provided with a communication section (72) for feeding oil which is caused to flow to the peripheries of an ignition plug (55) and an exhaust port (16) to the mating surface (70) between the cylinder head and the cylinder block. The oil return path (9) is provided in the cylinder block (12) so as to be separated from the communication section (72). A cylinder side oil path (92) for causing oil to flow from the communication section (72) to the oil return path (9) is provided in the cylinder block (12). The configuration simplifies the structure of the oil path (7) and prevents cooling oil temperature from increasing.