Research On Transfer Path Of Passenger Car Road Noise Based On OTPA Method

When the vehicle is running on the road,various noises such as wind noise,road noise,and engine noise are coupled with each other through the structural path and the air path,and finally superimposed to form the interior noise.The research goal of this paper is to identify the main transmission path that affects the noise in the vehicle when the vehicle is driving at a medium speed based on the OTPA method,that is,the low-frequency structural road noise that is transmitted to the vehicle body through the suspension system from the uneven road surface,and provides a way for the study of road noise Comprehensive "test-calculation-analysis" effective method.In this paper,the vehicle interior noise of a test sample car when driving on the road is the research object.Based on the theoretical research of the OTPA method,the road surface,tires,and suspension are established by determining the main connection positions of the front and rear suspension systems of the sample car and the body.36multi-input single-output noise OTPA models of the vehicle body and the right ear of the driver;the vibration acceleration signals of the passive end of the input points of the36 paths and the sound pressure signal of the driver’s right ear under two conditions of uniform acceleration and uniform speed are collected respectively OA analysis is performed on the obtained uniform speed working condition data;based on the obtained uniform acceleration working condition data,the singular value in the output signal is fitted by singular value decomposition,principal component reduction,and least square method to calculate the equivalent of each path Transfer function(transfer rate),and the accuracy of the transfer rate calculation is verified by the benchmark.The accuracy of the road noise OTPA model established in this paper is verified by comparing the fitted value of the in-vehicle noise calculated based on the OTPA method with the actual measured value of the operating conditions;through the calculation and analysis of the contribution of each path,the noise contribution of the entire frequency band is obtained The path with larger amount is the Z direction of the left rear trailing arm and the X direction of the left front shock absorber;the path with the larger contribution of the noise in the car at the peak frequency of 217 Hz is the Z direction of the left front shock absorber and the Y direction of the left front shock absorber,and the vehicle The internal noise mainly comes from the vertical(Z-direction)excitation transmitted by the uneven road surface,rather than the horizontal(X,Y-direction)excitation;comprehensive analysis of the transmission rate and input excitation of the path that has a greater influence on the noise inside the car,accurate judgment Which of the two plays a leading role indicates a specific optimization direction for reducing the overall interior noise and weakening the peak interior noise.