Patent ID: 8381697

Claim:
An internal combustion engine comprising: a crankcase composed of a pair of cases, said cases being coupled to each other at mating surfaces orthogonal to an axis of a crankshaft; an oil sump chamber located below said crankshaft and formed at a lower part of said crankcase in the manner of ranging across said mating surfaces; an engine hanger boss provided in said crankcase and disposed adjacent to said oil sump chamber; and an oil pump for sucking oil from said oil sump chamber; wherein said crankcase is provided therein with an oil suction passage for making said oil pump and an end part of a bottom wall of said oil sump chamber communicate with each other, passes between said oil sump chamber and said hanger boss, and has a lowest part located below said bottom wall of said oil sump chamber, wherein said oil sump chamber includes: a first oil sump chamber and a second oil sump chamber, and an oil introduction port opening in a vertical direction providing for the oil from the first oil sump chamber to flow downwardly through the oil introduction port, and into the second oil sump chamber.