Research On Interior Noise In Middle And High Frequency And Optimal Sound Package Design Of Electric Battery MPV

Noise and vibration performance is the key factor in the evaluation of vehicle quality,and interior noise problem have great influence in riding comfort and safety of drivers and passengers.The interior noise level of electric vehicle is usually lower than that of traditional vehicle.However,middle and high frequency noise problem of motor in car is extremely noteworthy.The paper focuses on a battery electric multi-purpose vehicle,aiming at reducing interior middle and high frequency noise and vehicle weight,and do some researches on optimal sound package design and component improvement.The main researches of the article are as the followed:(1)According to the fundamentals of Statistical Energy Analysis Method(SEA),structure subsystems and acoustic cavity subsystems were divided and built,and these subsystems were linked.Then the physical properties of these subsystems were defined,and the basic analyzed parameters were calculated.(2)For verifying accuracy of the SEA mode,vehicle noise tests were carried out in semi-anechoic room.The tests including Power Based Noise Reduction(PBNR)test and test on exterior and interior sound pressure level of the BEV on driving condition.(3)Sound package was added in the vehicle SEA mode.PBNR and interior Sound Pressure Level(SPL)was calculated using the SEA mode.By comparing the simulated results and experimental results,the accuracy of the SEA mode was verified.After the SEA mode was verified,motor noise was used as incentive,interior noise was predicted.(4)The SEA mode was used to analyze transfer path of the motor noise,and the main paths and its energy contribution ratio were presented.By doing transfer path analysis,the weakness subsystems were acquired.(5)The critical factor impacting on sound insulation property of plate and acoustical property of material combination were studied.Optimal researches are as followed:heavy sound insulation material EVA was replaced as light sound absorption material TCF;acoustic package of floor was multi-objective optimized;window glasses were orthogonal designed;acoustic package of motor shell was optimized,the optimum shape and material of sound package were confirmed.After analysis and optimization,sound pressure level of driver head was decreased significantly,and the weight of vehicle was reduced.The goal of noise reduction and light weight was realized.The researches have reference significance on sound package optimization of BEV.