camshaftdriven

Camshaft-driven describes a mechanism in which a camshaft provides the primary motion that operates other components, most commonly the valves in an internal combustion engine. As the camshaft rotates, its lobes contact followers, pushrods, rocker arms, or directly act on valve lifters to time the opening and closing of intake and exhaust valves in synchronization with piston position. The result is controlled air–fuel intake and exhaust gas expulsion throughout the engine cycle.

In automotive engines, camshaft configurations vary by location and arrangement. Overhead camshaft (OHC) designs place the camshaft(s) in the cylinder head, with single overhead cam (SOHC) or dual overhead cam (DOHC) layouts commonly used to optimize valve control and valve count. In in-block or overhead-valve (OHV) designs, the camshaft resides in the engine block and actuates valves via pushrods and rocker arms. Both approaches are camshaft-driven, differing mainly in camshaft placement and valve-train topology.

Drive methods for camshafts can include timing belts, timing chains, or gears that connect the camshaft to the crankshaft or another drive source. Belt and chain drives require periodic maintenance or replacement, while gear-driven camshafts emphasize robustness at the expense of noise and cost. Accurate cam timing is essential for engine performance, fuel efficiency, and emissions.

Modern engines often employ variable valve timing (VVT) with camshaft phasing, allowing the relative timing of cam lobes to be adjusted in response to operating conditions. Outside automotive use, camshaft-driven mechanisms also appear in pumps, indexing devices, and other machinery where precise controlled motion is needed.