Also see: Variable Valve Timing, VTEC, VVT-i, VANOS Variable valve timing, or VVT, is a generic term for an automobile piston engine technology. ... VTEC (standing for Variable valve Timing and lift Electronic Control) is a system developed by Honda Motor Co. ... VVT-i, or Variable Valve Timing with Intelligence, is an automobile variable valve timing technology developed by Toyota. ... VANOS (Variable Nockenwellen Steuerung) is an automobile variable valve timing technology developed by BMW in close collaboration with Continental Teves. ...

This BMW innovation is the first production Variable Valve Timing system to offer continuously variable timing (on both intake and exhaust camshafts) along with continuously variable intake valve lift, on the intake camshaft only. BMW AG (an abbreviation for Bayerische Motoren Werke AG, or in English, Bavarian Motor Works), is a German company and manufacturer of automobiles and motorcycles. ... Variable valve timing, or VVT, is a generic term for an automobile piston engine technology. ... The camshaft is an apparatus used in piston engines to operate poppet valves. ...

First introduced by BMW on the 316ti compact in 2001, Valvetronic has since been added to many of BMW's engines. The Valvetronic system is coupled with BMW's proven double-VANOS, to further enhance both power and efficiency accross the powerband. VANOS (Variable Nockenwellen Steuerung) is an automobile variable valve timing technology developed by BMW in close collaboration with Continental Teves. ...

Cylinder Head's with Valvetronic use an extra set of rocker arms, called intermediate arms, positioned between the valve stem and the camshaft. These intermediate arms are able to pivot on a central point, by means of an extra, electronicly actuated camshaft. This movement alone, without any movement of the intake camshaft, can open or close the intake valves. For the computer software/games company, see Valve Software A valve is a device that regulates the flow of fluids (either gases, fluidised solids, slurries or liquids) by opening, closing, or partially obstructing various passageways. ...

Because the intake valves now have the ability to move from fully closed to fully open positions, and everywhere in between, the primary means of engine load control is transferred from the throttle plate to the intake valvetrain. By eliminating the throttle plates "bottleneck" in the intake track, pumping losses are reduced and fuel economy is improved.

It is important to note however, that the throttle plate is not removed, but rather defaults to a fully open position once the engine is running. The throttle will partially close when the engine is first started, to created the initial vacuum needed for certain engine functions, such as emissions control. Once the engine reaches operating speed, a vacuum pump run of the passenger side exhaust camshaft (on the N62 V8 only) provides a vacuum source, much as a diesel engine would, and the throttle plate once again goes to the fully open position.

The throttle plate also doubles as an emergency backup, should the Valvetronic system fail. In this case, the engine would enter a "limp home" program engine speed would once again be controlled by the throttle plate.

BMW 3 Compact 4 Cylinder Engine BMW Compact Article at New Car Net