Elementary Cam Lift Curve Synthesis

Abstract

This chapter describes the derivation and piece-wise integration of the first half of an analytically simple valve acceleration curve. Two simultaneous algebraic equations are obtained. The first equates an expression for the velocity on the nose of the cam to zero, and the second the sum of the increments of valve lift to the maximum specified lift. The two unknowns are the maximum positive acceleration, which is on the flank of the cam and the maximum negative acceleration, which is on the nose of the cam. The two equations can then be solved for these two unknown quantities. This example has been chosen for analytical simplicity, to demonstrate the method, but such an acceleration curve would not result is a good cam design with smooth valve acceleration, and should not be used in practice. A superior and useable, but analytically more complex acceleration curve is considered in the next chapter.