Dry-sump lubrication type four-stroke cycle engine

摘要

A dry-sump lubrication type four-stroke cycle engine having a crankcase provided with a crankshaft chamber in its front part and a transmission chamber in its rear part, a generator chamber on one side of the crankcase in an axial direction of the crankshaft, and a clutch chamber on the other side of the crankcase. The crankshaft chamber and the transmission chamber are separated by a partition wall of a predetermined height to form an oil reservoir chamber in a lower part of the transmission chamber. An auxiliary oil reservoir chamber is formed in a lower part of the clutch chamber. A suction chamber is formed under a crankshaft chamber bottom wall defining a bottom of the crankshaft chamber so as to communicate with a suction port of a scavenging pump of the engine. The suction chamber opens into the crankshaft chamber through a first suction hole formed in the crankshaft chamber bottom wall and opens into the generator chamber through a second suction hole formed in a wall defining the bottom of the generator chamber. The scavenging pump pumps up oil directly from the suction chamber and discharges oil into the oil reservoir chamber.