Oil storage structure for engine, engine incorporating same, and vehicle incorporating same

An internal combustion engine, comprising

• a crankshaft;
• a transmission shaft operatively connected with said crankshaft;
• a crankcase rotatably supporting said crankshaft and said transmission shaft therein;
• the crankcase being vertically split into an upper crankcase and a lower crankcase;
• a clutch mechanism comprising a clutch arranged on an end portion of the transmission shaft;
• a crankcase cover joined to the crankcase;
• a partition wall extending along an outer circumference of the clutch mechanism, as viewed in an direction of the transmission shaft;
• wherein the partition wall splits a space between the lower crankcase and the crankcase cover into a pair of chambers including a clutch mechanism chamber and an oil storage chamber;
• wherein said oil storage chamber is separate from said clutch mechanism chamber;
• an upper edge portion of the partition wall is at least partially disposed along a case-split surface such that the oil storage chamber is formed only by said lower crankcase and the crankcase cover.

A vehicle comprising a two-cylinder internal combustion engine, said engine comprising

• a crankshaft;
• a transmission shaft operatively connected with said crankshaft;
• a crankcase rotatably supporting said crankshaft and said transmission shaft therein;
• said crankcase comprising an upper crankcase and a lower crankcase;
• a clutch mechanism comprising a clutch arranged on an end portion of the transmission shaft;
• a crankcase cover joined to the crankcase;
• a partition wall extending along an outer circumference of the clutch mechanism, as viewed in an direction of the transmission shaft,
• wherein the partition wall splits a space between the lower crankcase and the crankcase cover into a pair of chambers including a clutch mechanism chamber and an oil storage chamber;
• wherein said oil storage chamber is separate from said clutch mechanism chamber, and is formed only by said lower crankcase, the crankcase cover and the partition wall.