Analysis And Optimization Of Road Noise Problem Of A New Energy Vehicle

Most of the new energy vehicles are driven by motor at present,which lack of the engine masking.So tire/road noise,wind noise and high frequency noise inside the car become prominent and are easier to reduce the ride comfort of the vehicle,which has been a research priority for the auto industry.Vibration and noise caused by r oad roughness excitation belong to the low frequency noise and are mainly distributed in the range of 30-300 Hz.The low frequency noise is annoying,anxious and uncomfortable.Therefore,studying the mechanism of low frequency road noise and making effective noise reduction measures are able to improve the user’s sensory experience and enhance the core competitiveness of the products.This paper uses the method of combining the finite element simulation analysis and experiments to study the road noise based on an electric vehicle.First,establish the finite element models of the BIW,Trimmed Body and the full vehicle.Then,compare and analyze the simulation results with the experiment results to control simulation and experimental error within 5%,leading a good foundation for the analysis of the road noise.According t o the test of the road noise,extract the centripetal acceleration and use the Spindle Load method to calculate the Spindle Force.Finally,input the Spindle Force into the CAE model to calculate the road noise.The comparison of the road noise simulation results and test data shows that,the two curves overall trend is consistent and some differences in several peaks are related to the nonlinear parameters of the vehicle model.According to the curve peak,TPA is performed to find the greatest contribution at the peak point.After the optimization scheme is designed,the flexural modal of anti-away bar increases 22.3Hz and its weight reduces 0.8kg.It is obvious that the optimization scheme of the rear suspension Anti-away bar can improve the NVH performance and meetthe lightweight performance requirements.The test results show that,the modal of the anti-away bar is very close to the simulation results.The error is only 2.5% and the accuracy of the simulation model can be verified.What’s more,real vehicle validation results indicate that the anti-away bar area of the peak decreases 11.1dB(A),which achieves the expected effect and meets the requirement of evaluation.In consideration of the peak caused by 200-220 Hz tire acoustic modes,adopt the tire with good comprehensive performance provided by supplier.The test results declare that 200 Hz tire cavity resonance sound reduces about 4dB(A).In conclusion,the road noise simulation results can be used to guide the design,and identify and resolve the problems before the engineering design data is frozen.It provides theoretical basis for interior noise diagnosis,shortens the development cycle and reduces costs for vehicle companies.Due to the limitations of existing technology,the simulation and the experiment methods should be used together to achieve better results when solving practical problems.