Search results
Results from the WOW.Com Content Network
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.
With traditional fixed valve timing, an engine will have a period of "valve overlap" at the end of the exhaust stroke, when both the intake and exhaust valves are open. The intake valve is opened before the exhaust gases have completely left the cylinder, and their considerable velocity assists in drawing in the fresh charge.
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.
For twin-cam or DOHC engines, VCT was used on either the intake or exhaust camshaft. (Engines that have VCT on both camshafts are now designated as Ti-VCT.↓) The use of variable camshaft timing on the exhaust camshaft is for improved emissions, and vehicles with VCT on the exhaust camshaft do not require exhaust gas recirculation (EGR) as retarding the exhaust cam timing achieves the same ...
MIVEC achieves both goals. With MIVEC, the "cam swap" occurs automatically at a fixed engine speed. The Cam Switch operation is transparent to the driver, who is simply rewarded with a smooth flow of power. [8] Two distinct cam profiles are used to provide two engine modes: a low-speed mode, consisting of low-lift cam profiles; and a high-speed ...
The cams open (lift) the valves kind for a certain amount of time (duration) during each intake and exhaust cycle. The timing of the valve opening and closing, relative to the position of the crankshaft, is important. The camshaft is driven by the crankshaft through timing belts, gears or chains.
Camshafts; Connecting rods (rotating around the piston end as required by the varying horizontal offset between the piston and the crank throw) The imbalances can be caused by either the static mass of individual components or the cylinder layout of the engine, as detailed in the following sections.
VVT-i varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position. Adjustments in the overlap time between the exhaust valve closing and intake valve opening result in improved engine efficiency.