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A camshaft operating two valves. A camshaft is a shaft that contains a row of pointed cams in order to convert rotational motion to reciprocating motion.Camshafts are used in piston engines (to operate the intake and exhaust valves), [1] [2] mechanically controlled ignition systems and early electric motor speed controllers.
A desmodromic valve is a reciprocating engine poppet valve that is positively closed by a cam and leverage system, rather than by a more conventional spring. The valves in a typical four-stroke engine allow the air/fuel mixture into the cylinder at the beginning of the cycle and exhaust spent gases at the end of the cycle.
The cam can be seen as a device that converts rotational motion to reciprocating (or sometimes oscillating) motion. [clarification needed] [3] A common example is the camshaft of an automobile, which takes the rotary motion of the engine and converts it into the reciprocating motion necessary to operate the intake and exhaust valves of the cylinders.
In piston engines, the valves are grouped into 'inlet valves' which admit the entrance of fuel and air and 'outlet valves' which allow the exhaust gases to escape. Each valve opens once per cycle and the ones that are subject to extreme accelerations are held closed by springs that are typically opened by rods running on a camshaft rotating ...
Cutaway of a dual overhead camshaft engine 1969 AMC V8 overhead valve engine. The rocker cover has been removed, so the pushrods, rocker arms, valve springs, and valves are visible. A valvetrain is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. [1]
A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. [1] This enables the direct control of flow rate and the consequential control of process quantities such as pressure , temperature , and liquid level.
These valves allow the engine to inhale air (or an air/fuel mixture) and exhale the exhaust gasses. [2] The most common devices to transfer the drive are toothed rubber belts, metal timing chains or a set of gears. The teeth of the belt/chain/gears mesh with both the crankshaft and camshaft(s), thereby synchronising their motion.
Its movement is driven by the camshaft via a series of components. VVEL varies valve lift by the eccentric control shaft inside the rocker arm. By rotating the eccentric control shaft, the position of rocker arm is shifted, changing the swing angle of cam. The swing angle of cam determines the degree of valve lift. [7]