Vehicle internal combustion engine

摘要

A vehicle internal combustion engine wherein the vertical height of a crankcase is made short in addition to making short the anteroposterior (front to back) length of the crankcase. A vehicle internal combustion engine is configured such that a crankshaft, a main shaft, a counter shaft and an output shaft are arranged in parallel in a crankcase with the main shaft being disposed to the rear of the crankshaft and the counter shaft is disposed to the rear of the main shaft. The output shaft is disposed below and forward of the counter shaft.

主权项

1. An internal combustion engine for a vehicle, comprising:
a crankshaft; a main shaft; a counter shaft; an output shaft; and a shift drum adapted to switch a combination of gears on the main shaft and the counter shaft, wherein the internal combustion engine is a V-type internal combustion engine having cylinders arranged in a V-shape, the crankcase of the internal combustion engine includes vertically halved upper and lower case members, and the shift drum is disposed in the upper case member in a position that is under a rear cylinder bank, above the counter shaft and the main shaft, forward with respect to the counter shaft, and rearward with respect to the main shaft, said crankshaft, main shaft, counter shaft and output shaft is arranged in parallel in a crankcase, and when the engine is viewed from a direction parallel to axes of the crankshaft, the main shaft, the counter shaft, and the output shaft, the main shaft is seen to be disposed in a rearward direction of the vehicle with respect to the crankshaft, the counter shaft is seen to be disposed in the rearward direction of the vehicle with respect to the main shaft, and the output shaft is seen to be disposed below and in a forward direction of the vehicle with respect to the counter shaft, and further comprising: an oil pump; a drive shaft of the oil pump located in a position under the rear cylinder bank and forward with respect to each of the main shaft and the output shaft; and a drive chain for transmitting power from the main shaft on a horizontal mating surface to the drive shaft of the oil pump.