Research On Vibration And Noise Experiment And Performance Optimization Of The Pure Electric Bus

Comfort is an important indicator of vehicle performance.Improvement of vehicle comfort can significantly improve the passenger experience and it is of great significance to expand the market.The pollution of the environment caused by traditional vehicles is very serious.New energy vehicles can significantly improve the environment.The development of pure electric vehicles is still in its infancy and there are many deficiencies,among which the NVH problem is more significant.Therefore,studying the NVH problem of pure electric vehicles has important theoretical research value and practical significance.The research work of the paper is as follows:(1)Based on the NI-PXI vibration and noise test platform for a pure electric vehicle,a vehicle vibration and noise signal acquisition system was set up,and subsequent analysis of the collected test data was performed.One-third octave analysis of noise,vibration analysis of nonlinear components,and order analysis under accelerated conditions were used to process the data.The vehicle NVH quality was objectively evaluated and optimization recommendations were made.(2)Applying the transfer path method,the vehicle is studied from the perspective of "excitation source-transmission path-target point".The hammer was used to obtain the transfer function.Excitation force is calculated reversely.LMS.test.lab software is used to calculates the contribution of each path to the vibration of the target point.Analysis of sensitive sections of the main contribution path is conducted to clarify the source of the problem.The results show that the motor powertrain mounting system is an important factor causing the vibration in the vehicle.(3)In order to solve the problem of the general vibration isolation effect of pure electric passenger cars,the optimization design work of the motor powertrain mounting system was carried out.A six-degree-of-freedom rigid body model for powertrain was established.Under the initial settings,the vibration response analysis is performed to obtain the natural frequency,the modal decoupling ratio,and the dynamic reaction force response.The minimum value of anti-torque around the rotation direction of the motor is the optimization goal.The design parameters of the mount system are optimized using Isight and Matlab simulation.Compare the vehicle dynamic response results before and after parameter optimization.The results show that the vibration isolation effect of the optimized rear suspension system is significantly higher than that before optimization.For the study of the vibration and noise problems of a pure electric bus,this article provides new ideas for solving practical engineering problems.At the same time,it has important reference value and guiding significance for the follow-up research on NVH performance of pure electric vehicles.