Idea
The common valve spring system is satisfactory for traditional mass-produced engines that do not rev highly and are of a design that requires low maintenance. At the period of initial desmodromic development, valve springs were a major limitation on engine performance because they would break from metal fatigue. Vacuum melt processes developed in the 1950s helped remove impurities in the steel used to make valve springs, although after sustained operation above 8000 RPM often springs would still fail. The desmodromic system was devised to remedy this problem. Furthermore, as maximum RPM increases, higher spring force is required to return the valve, leading to increased cam drag and higher wear on the parts at all speeds, problems addressed by the desmodromic mechanism.
Read more about this topic: Desmodromic Valve
Famous quotes containing the word idea:
“It is very iniquitous to make me pay my debts—you have no idea of the pain it gives one.”
—George Gordon Noel Byron (1788–1824)
“The image cannot be dispossessed of a primordial freshness, which idea can never claim. An idea is derivative and tamed. The image is in the natural or wild state, and it has to be discovered there, not put there, obeying its own law and none of ours. We think we can lay hold of image and take it captive, but the docile captive is not the real image but only the idea, which is the image with its character beaten out of it.”
—John Crowe Ransom (1888–1974)
“The idea of the sacred is quite simply one of the most conservative notions in any culture, because it seeks to turn other ideas—uncertainty, progress, change—into crimes.”
—Salman Rushdie (b. 1947)