Studies on the Dynamic Characteristic of a Poppet Valve : 1st Report, Theoretical Analysis

This paper treats the self-excited lateral vibration of a poppet valve. It is shown that the static force proportional to displacement of a valve is strongly influenced by the pressure between a valve and its seat and that the dynamic force proportional to its velocity is effected by squeezing out fluid between a valve and its seat and also by the time rate of change of momentum of fluid. The effect of squeezing out fluid has a positive damping, while the time rate of change of momentum of fluid has a negative damping. Therefore, the self-excited lateral vibration of a valve occurs, when the latter damping becomes larger than the former.