Research On Vehicle Vibration Excited By Torsional Vibration Of The Powertrain

With the development of automobile towards lightweight and highspeed, the problem of torsional vibration of the powertrain has become increasingly prominent, which has become one of the main source of structural vibration and noise of automobile, and has attracted widespread concerned within the industry. Currently, a variety of mini-bus on the market has the problem of torsional vibration of the powertrain. Serious torsional vibration will not only adversely affect the life and safety of the powertrain components, but also bring the additional motivation to the body, and then affect the comfortable ride.This paper focuses on a FR mini-bus, using the method of simulation analysis and experimental research on combined, which has a systematic research on torsional vibration of the powertrain and vehicle vibration excited by torsional vibration, so as to solve the problem of booming which arises at low engine speeds, the main research contents are as follows:Firstly, vibration and noise test, the powertrain torsional vibration test, the transmission path test, body sheetmetal mode test have been carried out. The paper has used the coherent analysis method to carry on the correlation analysis of torsional vibration and noise. Test and analysis results show that the transfer path of powertrain torsional vibration is from the rear axle to rear suspension to the body, which has caused body sheetmetal resonance, and has resulted the low speed booming.Secondly, equivalent system of powertrain has been built, at the same time the free and forced torsional vibration has been calculated, which has verified the validity of the model. Based on this model, the vehicle AMESim model has been build up, of which can be considered vehicle longitudinal vibration. Comparing the longitudinal vibration acceleration of the AMESim simulation with the test, it is found that the two have the same change trend, which illustrates that longitudinal vibration model established is effective.Thirdly, based on vehicle vibration AMESim model, the paper has analyzed the influence law of the powertrain system parameters, the elastic damping shock absorber parameters and the dual mass flywheel parameters to the torsional vibration mode frequency, the final drive input forced torsional vibration response and vehicle longitudinal vibration acceleration response, providing reference for powertrain parameters optimization, selection of torsional vibration damper, and dual mass flywheel matching.Finally, from the view of control excitation, the paper has used two kinds of methods to solve the problem of the booming:one is to optimize the powertrain parameters, including the adjustment of the main reduction ratio, semishaft stiffness and the combination parameters; another is to install shock absorber device, including elastic damping torsional vibration damper (TVD) and dual mass flywheel (DMF). Simulation has forecasted the effectiveness of each scheme, and test has proved the control effect of each scheme.In summary, this paper has studied the mechanism of the booming by experiment, and has built the powertrain and vehicle model by using AMESim, has analyzed the influence law of the powertrain system parameters, torsional vibration damping device parameters to the torsional vibration and vehicle model, has proposed solutions to the booming problem. The above work can not only directly conduct the rectification of object vehicle, but also provide reference to analyze and solve the similar problems.