Multibody System Dynamics Modelling and Characteristic Prediction for One Diesel´s Valve Train

In this paper, as the multibody system dynamics analysis of one dieselpsilas pushrod-type valve train is concerned, the algorithm of calculation campsilas profiles from the lift of roller tappet is presented according to the kinematics analysis firstly. Then the flexible body models of the pushrod, rocker arm and valves that are considered to have significant flexibility are built. Comparing the analysis results with the experiment data, the flexible effects of these parts on dynamics characteristics of the valve train are determined. Based on these researches, the multi-flexible-body system dynamics model of this valve train is established, and the kinematics and dynamics characteristics under the enginepsilas rated speed are calculated. Moreover, the mechanismpsilas characteristics as the enginepsilas speed improved are predicted. The results shown that light lift-off occurs when the campsilas speed gets up to 1600 r/min, and valve bounce occurs when the campsilas speed gets up to 1900 r/min.