Research On Torsional Vibration Of Transmission System Under Engine Excitation

The torsional vibration problem of the automobile transmission system has always been the concern of automobile manufacturers and research institutes all over the world.The torque fluctuation caused by the engine working is the main factor that causes the torsional vibration of the transmission system.The Dual Mass Flywheel(DMF)torsional vibration damper solves the torsional vibration of the transmission system to a great extent and has been widely applied abroad.Therefore,it is still important to further study the torsional vibration characteristics of a transmission system equipped with dual mass flywheels under engine excitation.In this paper,we aimed to a front-pilot small SUV model,studyed the transmission system torsional vibration characteristics.First of all,the three-dimensional structure model of the vehicle powertrain was established by simplifying the engine,DMF and rigid clutch,gearbox,semi-axle and so on.Secondly,based on the principle of equivalent conversion of transmission system,the torsional vibration of the transmission system with dual mass flywheel Dynamics model,the inherent characteristics of the transmission system were analyzed by modal analysis.Finally,based on multi-body dynamics analysis method,a rigid-flexible multi-body dynamic simulation model of automotive transmission system was established by co-simulation of ADAMS and ABAQUS software.The second-order main harmonic torque function of the engine was input,Under the conditions of the vibration performance of a theoretical calculation and analysis.Conducting vehicle road test to explore the main excitation source that causes torsional vibration of transmission system and the actual vibration reduction effect of double mass flywheel.The signals of flywheel end and transmission input end of the engine were calculated and analyzed in time domain,frequency domain and order analysis.The excitation signal of the engine was obtained.The main factors that caused the torsional vibration of the transmission system were the 2nd order engine Harmonic.The comparison between simulation and test showed that the difference between the second order harmonic of the engine and the second order harmonic of the engine input from the torsional vibration test was very small,which proved the correctness of the experimental method.The frequency of the second harmonic of the engine corresponded to a much higher frequency than the low-order natural frequency of the transmission system,and the system hardly generated resonance.The actual vibration damping effect of the dual mass flywheel was obtained by comparing the angular acceleration curves of different measuring points of the torsional vibration test,The vibration reduction amplitude of the dual mass flywheel obtained from the analysis and simulation was basically the same,and the correctness of the rigid-flexible coupling simulation model was verified.This method can be used to analyze the performance of the dual mass flywheel in order to reduce the vehicle development costs and shorten the development cycle.