What are the differences between single overhead camshaft and double overhead camshaft?
1 Answers
Single overhead camshaft is arranged with one camshaft in a cylinder head, while double overhead camshaft is arranged with two camshafts in a cylinder head. The detailed introduction is as follows: Single overhead camshaft: Before the emergence of double overhead camshaft, single overhead camshaft was simply called OHC, as there was no distinction between single and double. The camshaft of a single overhead camshaft is located at the top of the cylinder, above the valves. The opening and closing of the valves are controlled by the shims between the crankshaft journals and the valve stems, or by rocker arms. The valve configuration of a single overhead camshaft engine usually has 2 to 3 valves per cylinder. There are also single overhead camshaft engines with 4 valves, but the rocker arms and camshaft journals become very complex. Double overhead camshaft: The camshaft is located on the cylinder head. In this structure, the camshaft directly drives the rocker arms, eliminating the need for tappets and pushrods, which greatly reduces the reciprocating mass. Therefore, it is suitable for high-speed engines. However, the timing transmission mechanism is complex, and it causes certain difficulties in disassembling and assembling the cylinder head. The double overhead camshaft means that the intake and exhaust valves are controlled by separate shafts.
