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Deutsch-Chinesische Enzyklopädie, 德汉百科
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可变气门升程系统,奥迪的AVS可变气门升程系统在设计理念上与本田的i-VTEC有着异曲同工之妙,只是在实施手段上略有不同。这套系统为每个进气门设计了两组不同角度的凸轮,同时在凸轮轴上安装有螺旋沟槽套筒。螺旋沟槽套筒由电磁驱动器加以控制,用以切换两组不同的凸轮,从而改变进气门的升程。
Das Audi valvelift system, eine der großen Innovationen der Marke mit den Vier Ringen, schaltet den Hub der Ventile in zwei Stufen um, je nach Last und Drehzahl. Damit steigert es das Drehmoment und reduziert zugleich den Verbrauch.
Das AVS-System steht in zwei Varianten bereit. Bei den V6-Motoren, bei denen es zum Einsatz kommt, wirkt es auf die Einlassventile; es steuert in weiten Bereichen die Menge an Ansaugluft. Die Drosselklappe kann auch bei Teillast weit geöffnet bleiben – die Drosselverluste sinken, der Motor atmet frei, der Wirkungsgrad steigt.
Beim 2.0 TFSI der jüngsten Generation variiert das AVS den Hub der Auslassventile. Es verringert die Spülverluste im Brennraum und sorgt für eine optimale Anströmung des Turboladers mit Abgas. Die einfache, kompakte und leichte Bauweise des Systems mit den so genannten Nockenstücken – elektromagnetisch verschiebbaren Hülsen auf der Nockenwelle – ist in beiden Fällen gleich.