A New Numerical Method for Developing the Lumped Dynamic Model of Valve Train

The dynamics of valve train is influenced by stiffness, size, and mass distribution of its components and initial valve clearance and so on. All the factors should be taken into consideration correctly by dynamic model and described qualitatively and quantitatively through mathematical variables. This paper proposes a new simplified method for valve train components, namely, mode matching method (MMM) for camshaft, pushrod, rocker arm, valve, and valve spring. In this method, the amount of lumped masses for each flexible component is determined based on its natural frequencies and the considered frequency range. As a result, the dynamic model of each component is required to match its low order modes within the considered frequency range. The basis of this method is that the contributions of each component to valve train vibration are mainly in the low order modes. The numerical model of valve train is verified by an experiment conducted on a motor driven valve train system.