Overhead camshaft driving mechanism for V-type or horizontally-opposed i.c. engine

摘要

The V-type (fig.1) or horizontally-opposed (fig.4) engine 10 has a cylinder block 16 extending to each side of a crankshaft, a first cylinder head 28 on one side of the cylinder block and a second cylinder head 30 on the other side of the cylinder block. Each cylinder head 28, 30 includes at least one camshaft 32, 34 for opening and closing intake and exhaust valves respectively. A first chain or belt 40 transmits drive from the crankshaft 22 to the camshafts 32,34 of the first cylinder head and also drives an idler shaft 50. A second chain or belt 44 transmits drive from the idler shaft 50 to the camshafts 32,34 of the second cylinder head. The elongation of the first and second chains or belts 40, 44, eg due to wear, can be equalised, the length of the chain or belt can be shortened and the elongation thereof can be reduced. Further, the rotational angular deviation between the camshafts on both sides can be minimized.