Valvetronic

The Valvetronic system is a variable valve timing system to offer continuously variable timing (on both intake and exhaust camshafts) along with continuously variable intake valve lift, from ~0 to 10 mm, on the intake camshaft only. Valvetronic-equipped engines are unique in that they rely on the amount of valve lift to throttle the engine rather than a butterfly valve in the intake tract. In other words, in normal driving, the "gas pedal" controls the Valvetronic hardware rather than the throttle plate.

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 across the engine speed range. Valvetronic will not be coupled to BMW's N53, "High Precision Injection" (gasoline direct injection) technology due to lack of room in the cylinder head, or the N54B30 bi-turbo engine. Cylinder heads with Valvetronic use an extra set of rocker arms, called intermediate arms (lift scaler), positioned between the valve stem and the camshaft. These intermediate arms are able to pivot on a central point, by means of an extra, electronically actuated camshaft. This movement alone, without any movement of the intake camshaft, can open or close the intake valves.

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 plate's "bottleneck" in the intake track, pumping losses are reduced, fuel economy and responsiveness are 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 create the initial vacuum needed for certain engine functions, such as emissions control. Once the engine reaches operating speed, a vacuum pump run off the passenger side exhaust camshaft (on the N62 V8, exhaust cam on the N52/K) 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, and engine speed would once again be controlled by the throttle plate.

Valvetronic has so far been limited to BMW's mass-market engines, with no high-performance M-series car using the technology, which continue to utilise multiple throttle-bodied designs instead.


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Valvetronic — ist eine Bezeichnung des Automobil Herstellers BMW für eine Technik zur Ergänzung der Ventilsteuerung in Ottomotoren. Bei Valvetronic wird die Einlassmenge nicht wie üblich über eine Drosselklappe geregelt, sondern über einen variablen Ventilhub …   Deutsch Wikipedia

  • Continuous variable valve timing — offers a unique ability to have independent control of the intake and exhaust valves in an internal combustion engine. For any engine load criteria, the timing of intake and exhaust can be independently programmed [1]. The main variations of… …   Wikipedia

  • Drosselklappe — Drosselklappe, ca. 30 % geöffnet Um bei Ottomotoren die geforderte Abgabeleistung zu regulieren, wird die zugeführte Luft und Treibstoffmenge reguliert. Die Luftmenge wird dazu durch eine Drosselklappe im Saugrohr gesteuert. Inhaltsverzeichnis …   Deutsch Wikipedia

  • Drosselklappenpotentiometer — Drosselklappe, ca. 30 % geöffnet Um bei Ottomotoren die geforderte Abgabeleistung zu regulieren, wird die zugeführte Luft und Treibstoffmenge reguliert. Die Luftmenge wird dazu durch eine Drosselklappe im Saugrohr gesteuert. Inhaltsverzeichnis …   Deutsch Wikipedia

  • Variable valve timing — Variable valve timing, or VVT, is a generic term for an automobile piston engine technology. VVT allows the lift or duration or timing (some or all) of the intake or exhaust valves (or both) to be changed while the engine is in operation. Two… …   Wikipedia

  • Engine of the Year — Der International Engine of the Year Award ist ein jährlich stattfindender Wettbewerb, bei dem eine Reihe von Autojournalisten aus aller Welt die besten Motoren in verschiedenen Kategorien prämieren. Er wird von Großbritanniens größten… …   Deutsch Wikipedia

  • BMW X1 — X1 Hersteller: BMW Produktionszeitraum: seit 2009 …   Deutsch Wikipedia

  • BMW E90 — BMW BMW 3er Limousine (2005–2008) E90/E91/E92/E93 Hersteller: BMW Verkaufsbezeichnung …   Deutsch Wikipedia

  • BMW E91 — BMW BMW E90 (2005–2008) E90/E91/E92/E93 Hersteller: BMW Verkaufsbezeichnung: BMW 3er Produktionszeitraum …   Deutsch Wikipedia

  • BMW E92 — BMW BMW E90 (2005–2008) E90/E91/E92/E93 Hersteller: BMW Verkaufsbezeichnung: BMW 3er Produktionszeitraum …   Deutsch Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.