Valve Timing

In a piston engine, the valve timing is the precise timing of the opening and closing of the valves.

In four-stroke cycle engines and some two-stroke cycle engines, the valve timing is controlled by the camshaft. It can be varied by modifying the camshaft, or it can be varied during engine operation by the relatively new technology of variable valve timing. It is also affected by the adjustment of the valve mechanism, and particularly by the tappet clearance. However, this variation is normally unwanted.

Many two-stroke cycle and all wankel engines do not have a camshaft or valves, and the port timing can only be varied by machining the ports, and/or modifying the piston skirt (two stroke applications). Some supercharged two-stroke diesel engines do however have a cylinder head and camshaft similar to a four-stroke cycle engine.

In a steam engine, the control of the valve timing is an important part of the operation of the engine.

Other articles related to "valve timing, valve, valves, timing":

Continuous Variable Valve Timing - Drawbacks
... produce a cost effective means of controlling the valve timing under the conditions internal to an engine ... Every second, the crankshaft rotates 25 times, so the valve timing events have to occur at precise times to offer performance benefits ... Electromagnetic valve actuators offer the greatest control of precise valve timing, but are not cost effective for production vehicles at this time ...
Variable Valve Timing - History - Aircraft
... radial engine of the early 1920s incorporated variable valve timing gear, mainly to vary the inlet valve timing in connection with higher compression ... The Lycoming R-7755 engine had a Variable Valve Timing system consisting of two cams that can be selected by the pilot ...
Variable Valve Event And Lift
... Nissan Variable Valve Event and Lift (commonly abbreviated as "VVEL") is an automobile variable valve timing technology developed by Nissan ... VVEL variable valve timing is now also used in the VK50VE V8 engine from the Infiniti FX50 ... A rocker arm and two types of links open the intake-valves by transferring the rotational movement of a drive shaft with an eccentric cam to the output cam ...
... MIVEC (Mitsubishi Innovative Valve timing Electronic Control system) is the brand name of a variable valve timing (VVT) engine technology developed by Mitsubishi Motors ... MIVEC, as with other similar systems, varies the timing of the intake and exhaust camshafts which increases the power and torque output over a broad engine speed range while also being able to help spool a. 1992 in their 4G92 powerplant, a 1,597 cc naturally aspirated DOHC 16 valve straight-4 ...

Famous quotes containing the word timing:

    A great man always considers the timing before he acts.
    Chinese proverb.