Talk:Camless

From Wikipedia, the free encyclopedia

	It is requested that a photograph or photographs be included in this article to improve its quality.
	The Free Image Search Tool (FIST) may be able to locate suitable images on Flickr and other web sites.

[edit] Desmodromic not "camless".

Desmodromic systems are not "camless", I don't know what that's doing in here. TomRawlinson 15:07, 5 May 2007 (UTC)

Sliding friction between the surface of the cam and the cam follower which rides upon it is considerable. In addition to mechanical friction, considerable force is required to overcome the valve springs used to close the engine's valves. This can amount to an estimated 25% of an engine's total output at idle, reducing overall efficiency. A roller follower valvetrain has significantly less friction and allows for concave cam lobes. Two approaches have been tried to reclaim this "wasted" energy of the valve spring, but have proven difficult to implement:

I don't know where this info came from but it is very misleading. Considerable force is not required to overcome the springs. When a spring is compressed it is holding the energy used to compress it and will release that energy back to the valvetrain when it is uncompressed. This is why there is no negligible harm in using slightly heavier springs in a valvetrain than required. 25% seems very overexaggerated.LrngCrv (talk) 05:29, 11 January 2008 (UTC)

[edit] Camless engines already in production

MAN B&W Diesel are already producing engines which make use of electrohydraulic valve control rather than camshafts, rocker arms and pushrods.

http://www.mandiesel.com/files/news/filesof2810/p412-0503.pdf

The current article is so exclusively car-focused that I don't know how to slide this in. Anyone else care enough? --Joffeloff (talk) 00:10, 17 March 2008 (UTC)