Research On A Suv Interior Booming Noise Analysis And Control

As consumer's vehicle comfort requirements increase, the auto manufacturers are increasingly urgent to improve the NVH quality. Vehicle interior sound quality is a very important factor desided vehicle's performance. Car passenger booming noise is universal issue at present. Vehicle boom noise has great impact on human ear comfort. This study to acceleration boom noise developed of a JMC developed SUV. The boom noise is divided into structures and airborne. This paper study the transfer path of this boom including the inherent characteristics of the main systems,identify the root cause of boom, and then take corresponding optimization methord. This paper focus a structural boom noise, The result of this paper show important engineering value for further NVH attribut development of the physical prototype vehicle and its optimization.This paper study on Jiangling Motor SUV, Study the identification and control method for two different frequencie boom r. Through large number diagnostic tests work, expecially booming noise transfer path in-depth research. Based on theoretical deduction and experimental verification method, find thetuned mass damper and torsional damper design methods and engineering methods. The interior boom noise get greatly reduced and achieve the original set targets and also reach cunsumer acceptable level. In this paper pay attention to characteristics of the car boom noise test identification, roaring noise control methods. And also perform a more in-depth research on the understanding the relationship of powertrain, rear axle mode between boom . Provide a reference for domestic automobile manufacturers to solve similar problems . This article contend as follows:First, the interior noise subjective and objective assessment and analysis methord. In the identification process. We organized subjective assessment driving according to Ford standard .Using LMS Test.lab data acquisition and analysis system, identify the speed up process noise is around 1450 and 1750 rpm. And apply order analysis find the 2nd order accounts for the main contribution, find the problem frequency cfrequencies are around 47Hz and 58Hz . At the same time perform roof and the rear axle vibration test and found that vibration in good agreement with boom features, then check the boom noise is structureborne. This makes it easier to find the noise sourch and transfer path.Second, analysis the elastic element on the active side and the passive side of the vibration data in detail, by comparing the vibration amplitude and found that the passive side vibration amplification at some frequency.Third, test the BIW modal and body cavity modal, found the cab shows modal in 46Hz composed 55.5Hz . the body has complex modal alignment and partial mode at these frequecies. And find the poor modal separation may lead to serious interior boom noise.Fourth, expatiate the sources of engine torsional vibration, based on the torsional vibration test methods and principles, using a non-contact torsional vibration test systems, to finish torsional vibration test. The detail test location include clutch disc input and output side, shaft end (front end of rear axle). Test results show that the clutch disc and drive shaft rear end show torsional vibration peak between 1650-1850RPM, peak frequency is about 58Hz, Prove the frequecy is caused by driveline vibration, and this is useful to tell where to install the torsional damper.Fifth, expatiate operation shape deformation (ODS) test techniques in details, and apply the LMS software to carry out bridge, body, powertrain chassis system ODS test, test results show that these tested system has clear peak vibration around 1450 rpm and 1800 rpm peak frequency match well with the boom noise frequency. Carry out ODS test just for the rear axle, we get the rear axle modal shape at 1450 and 1750. the ODS animation modes provide a basis for later tuned mass damper installed. Based on the above study, conducted on a separate rear axle modal test analysis showed that 46.1 and 56.75 Hz has the modal frequency, thus obtained the booming noies's two possible sources and paths.Based on the above studies, establish tuned mass damper and study its principle of mathematical model. Summarize general design steps of tuned mass damper. Detailed discuss several key impact factor of tuned mass dampers, then trial out of the two types tuned mass dampers, that is vertical tuned mass damper and torsional vibration damper (TVD) They are used to solve frequency of 47Hz and 58Hz.Through the actual test,this is successful solution of the interior noise around 1450 and 1750 rpm.and this is what the study need to get.The previous shows that the TMD and the TVD manual parts show good performance to solve the boom noise. Study the engineering method of these two parts. The influence factor including location, rubber materials, fixed bolts and other factors.At the same time, discussof the TMD frequency control method during production, these can be used as wide range of guidance for other auto company.