Ventilzugs

Ventilzug (plural Ventilzüge) is a term used in German mechanical engineering to describe the part of a valve actuation system that transmits motion from a driving element to the valve itself. The function of the Ventilzug is to convert rotational or oscillatory motion, produced by a cam, eccentric, or similar drive, into the linear opening and closing movement of a valve. It forms a key element of the broader valve train (Ventiltrieb) found in various machines and engines.

In internal combustion engines, the Ventilzug is part of the valve train and may include components such as pushrods, rocker arms, tappets, and interfaces with the valve stems and springs. Its primary roles are to ensure correct valve timing, lift, and duration in relation to piston position and cycle. Different engine layouts use different arrangements: in some designs the camshaft directly actuates the valve via tappets or rocker arms, while in others pushrods transmit the motion to overhead or side-mounted valves. Modern engines may employ hydraulic lash adjustment and variable valve timing within the broader valve train, which can affect the function and design of the Ventilzug.

In steam engineering, a related concept appears in valve gear systems that actuate steam admission and exhaust through piston or slide valves. Here, linkages and rods transmit motion from cranks or eccentric cams to the valve, and the resulting motion controls the timing and duration of steam flow. Notable historical valve gear types include Stephenson and Walschaerts, which are described in German sources as forms of Ventilsteuerung or Ventilzug mechanisms.

Overall, the Ventilzug denotes the linkage portion of valve actuation responsible for translating drive motion into valve movement, with variations across automotive, aviation, and locomotive technology.