The oil road null cylinder block for cylinder head cooling of

摘要

PROBLEM TO BE SOLVED: To reduce the unevenness of cooling of a cylinder block by reducing a difference in the temperature of oil between the supply side and the discharge side of the cylinder block in an oil path for cooling the cylinder head of a multicylinder engine in which a supply oil path and a discharge oil path connected from the cylinder block to the ignition plug oil jacket of the cylinder head are formed.;SOLUTION: A bypass oil path which does not extend through the ignition plug oil jacket is provided to the cylinder block. The bypass oil path is formed of a groove formed in the upper surface of the cylinder block and the lower surface of the cylinder head which closes the upper part. The engine is an air-cooled type having air-cooling fins on the cylinder block. The supply oil path is disposed forward of a cylinder in a vehicle advancing direction, and the discharge oil path is disposed rearward of the cylinder.;COPYRIGHT: (C)2010,JPO&INPIT