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:
“... the idea of a classless society is ... a disastrous mirage which cannot be maintained without tyranny of the few over the many. It is even more pernicious culturally than politically, not because the monolithic state forces the party line upon its intellectuals and artists, but because it has no social patterns to reflect.”
—Agnes E. Meyer (1887–1970)
“I am writing to resist the view that Europe and civilization are going to Hell. If I am being “crucified for an idea”Mthat is, the coherent idea around which my muddles accumulated—it is probably the idea that European culture ought to survive, that the best qualities of it ought to survive along with whatever cultures, in whatever universality. Against the propaganda of terror and the propaganda of luxury, have you a nice simple answer?”
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“We are all ill: but even a universal sickness implies an idea of health.”
—Lionel Trilling (1905–1975)