Valve spring
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The valve spring is in internal combustion engines , after the four-stroke working or valved two-stroke engines such as large and marine diesel engines, a spring, a valve stops for the intake of fuel-air mixture or for the outlet of combustion exhaust gas and residues in its seat; the valve spring closes the valve. The camshaft works against this spring , if necessary via rocker arms or the like, in order to open the respective valve at the right time; without cams, sniffer valves are opened. An alternative to the spring returning the valve is the complex desmodromic system ; the valve closing is also effected by a control cam.
Valve springs are usually one or two coil springs (concentric) with the valve stem ; and torsion bars have been used as valve springs, for example of the Honda-CB-450 motorcycle engine and in the two-cylinder piston engines of Panhard . Hairpin valve springs with a particularly low mass moment of inertia (on the Moto Guzzi motorcycle in the adjacent photo in an exposed, later often also in an encapsulated version) are a design of the leg spring ; Since the valve stems can also be kept shorter, higher speeds are possible. With the advent of better materials, they increasingly disappeared from racing around 1960. Well-known representatives of engines with hairpin valve springs include many English motorcycles from the 1930s, the NSU OSL 351 and 501 (also many modifications), BMW R 5, R 51 and R 66, the Climax V-8 racing engine from 1953 and the Maserati V-8 sports car engine from 1957.
Pneumatic valve springs are often used as spring elements in modern racing engines (for example in Formula 1 ).
literature
- Peter A. Wellers, Hermann Strobel, Erich Auch-Schwelk: Vehicle technology expertise. 5th edition, Holland + Josenhans Verlag, Stuttgart, 1997, ISBN 3-7782-3520-6
- Peter Gerigk, Detlev Bruhn, Dietmar Danner: Automotive engineering. 3rd edition, Westermann Schulbuchverlag GmbH, Braunschweig, 2000, ISBN 3-14-221500-X