The Valvetronic engine is the world's first engine without a throttle butterfly. Valvetronic allows the engine to run without a throttle butterfly, the cylinder charge being determined under part load as a function of the valve-opening period. The intake and outlet camshafts are driven by variable cam adjustment, BMW’s Vanos technology. A further advantage of this concept is that it allows worldwide use of the proven three-way catalyst for emissions management, thus meeting even the strictest emissions standards in the US.

Innovative technology was essential in order to reach the demanding objectives and functional requirements desired. However, at the same time, this concept demanded the utmost of the electronic control and management systems in the engine.

Concept:-

Taking nature as the role model: human beings also applythe Valvetronic principle.

A comparison with the human beingclearly explains how Valvetronic works: Whenever we are required to make agreat effort, we human beings breathe in a deep and long process ofventilation. Whenever we need less air, we do not throttle the supply of airby, say, closing our nose or our mouth, but simply breathe in a shorter,flatter process of ventilation. In a conventional combustion engine thethrottle butterfly is basically comparable to a human being keeping his nose ormouth at least partially closed. With its large valve lift (= deep, longventilation) and short valve lift (= flat, short process of ventilation),Valvetronic, on the other hand, is able to breathe in the same way as nature –always in line with current requirements, without any kind of throttling effectand therefore with maximum efficiency.

Note:- Similar topic on Valvetronic Engine is available here (It is not same)