Dynamic Simulation and AnalysisUsing ADAMS on a New Double-Rocker Variable Timing and Lift Valve Mechanism

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This study aims at dynamic simulation and analysis on a new double-rocker variable timing and lift valve mechanism conducted by using ADAMS, which is to optimize the preloaded value of the return spring for the adjustable rocker arm as well as the values of stiffness coefficient for the return springs on the first and second rocker arm according to how they affect the dynamic displacement of the rocker arms and the instantaneous valve lift. The optimal combinations of the selected design parameters for both the conventional and proposed new valve system are obtained by analyzing the simulation data using Taguchi method. The corresponding instantaneous power consumption and torque are further calculated for comparing and evaluating their performance and efficiency. The proposed system is intended to modify the conventional single rocker arm into a set of two rocker arms, called the first and second rocker arms respectively. The first rocker arm consists of a fixed rocker arm and an adjustable rocker arm. The latter is held by the adjusting slots engaging with the adjusting lugs on the control shaft, and thereby can be followed by the axial moment of the control shaft. The results show that the Taguchi method can quickly and effectively perform the sensitivity analysis of performance on the selected major design parameters. The calculated optimal combinations of the design parameters can be a valuable reference for the future development of this proposed new valve system.