Abstract
The nonlinear characteristic of coil spring component is mainly influenced by the frequency of the applied load. Most studies of the dynamic system including this component ignore this effect and show a relatively large difference between experimental and theoretical results. From this reason, the spring component in the automobile valve trainsystem should be studied with the frequency respect as well as the magnitude respect of the applied load. The dynamic characteristics of valve train system which includes the valve spring component is very important for the optimization of automotive power train design with both aspects of noise-reduction and performance. Cam profile is another major factor causing the nonlinear behavior to whole valve train system because it is very related to the frequency of applied load.
In this study, we have analyzed the characteristics of valve train system including both the nonlinear characteristics of valve spring and the shape of cam profile. In order to find out the valve spring behavior, we develop the test rig of valve train system and numerical computing software. By the investigation of the experimental results, it is found that valve spring is greatly effected by the magnitude of preload. In the numerical study, it is found that the nonlinear dynamic characteristics of spring such as surging phenomena is very related to cam profile and the frequency of the applied load. By comparing the results between experimental and numerical results we find good coincidence of tendency between the results with the respects of the nonlinear behaviors of valve spring.