Parametric Research Of Dual-Mass-Flywheel And Driveline Torsional Vibration Analysis

In the context of the increasing requirements for automobile NVH and economy performance by consumers and national standards,Dual-Mass-Flywheel(DMF),a solution to powertrain optimization,shows sufficient application advantages.However,up to now,there have been many technical barriers to DMF matching based on powertrain vibration attenuation,and the majority of the existing researches are based on the research method of Clutch-Torsional-Damper(CTD).Based on the DMFdriveline of a light bus,the system's torsional vibration is analyzed and the DMF kinetic parameters and torsional vibration reduction effect are investigated under different conditions.The followings are the main research contents of the paper.(1)Based on the existing researches,CTD design methods and DMF design experiences of the cooperative firm,the preliminary design and selections of DMF rotary inertia distribution,torsional stiffness and hysteretic torque are carried out for the light bus.(2)The equivalent transformation and parameter calculation of DMF powertrain components are carried out,and the driveline analysis models under start-up-idling condition and WOT condition are established.By taking idling condition as an example,the natural characteristics of DMF driveline are calculated and analyzed by Matlab,verifying that DMF can effectively reduce the second-order natural frequency of the driveline system and avert the idling resonance.However,it's proved that the driveline system is about to be resonated inevitably during the start-up process.(3)The control models of starter and engine excitation are established by SimulationX.Based on the analysis models,the torsional vibration simulation models of DMF driveline under start-up-idling condition and WOT condition are constructed,and the forced response simulations are carried out.The torsional vibration test of the real vehicle driveline under the corresponding research conditions are designed and conducted.The reponse characteristics and attenuation effect of DMF under start-up,idling and WOT conditions are analyzed based on the simulation and test results.The relative errors between the simulated and experimental evaluation parameters are within 7.5%,verifying the exactness of the models.(4)On the basis of the forced response simulation models of DMF driveline under start-up-idling condition and WOT condition,the influences of DMF rotary inertial distribution,torsional stiffness and damping on attenuation effect are investigated and analyzed,and the evaluation indexes of DMF vibration attenuation effect under different conditions are proposed.Based on the torsional vibration reduction effect under the whole research conditions,the requirements for DMF matching and design are put forward.This paper distinguishes the input excitation of DMF driveline under start-up and driving conditions.The evaluation indexes of DMF vibration reduction effect under different working conditions are put forward,which are applicable to the analysis of simulation and test results for driveline torsional vibration.The DMF matching principle is improved by revealing the requirements for DMF design under start-up condition,providing some guidences and references for DMF product design and matching.