Transfer path analysis and control of vehicle structure-borne noise induced by the powertrain

Abstract

Because of the higher requirements for vehicle comfort and people's increasing ecological consciousness, research on the interior noise in a vehicle has received wide concern, among which structure-borne noise is hard to diagnose and control. To solve the problem, the transfer path analysis method of powertrain structure-borne noise has been systematically analysed. By introduction of the powertrain source-path-receiver model, this method enables us to estimate and study the vibro-acoustic transfer functions and their operational forces. Since structure-borne noise is composed of multiple paths, the aim of this paper is to discuss different synthesis methods for this noise. On the basis of previous discussion, the transfer path analysis test of a certain vehicle is carried out, and the transfer function and operational data at idle and second-gear wide-open throttle are obtained. The test data are processed and an acoustic contribution analysis of the target is performed using LMS software. The results of analysis show that the right-hand side mount represents the main contribution path. Then the match principle of the bracket dynamic stiffness of the powertrain isolation system is proposed. On the basis of the transfer path analysis results and the above principle, the bracket on the body side of the right-hand side mount is improved by combination of the experimental transfer path analysis and the finite element method. The test results show that the A-weighted sound pressure level of the interior noise at idle and second-gear wide-open throttle are reduced by 2.9 dB(A) and 4 dB(A) respectively after improvement. Also there is no obvious booming noise at second-gear wide-open throttle. It is expected that this paper can help automotive noise, vibration and harshness engineers to perform trouble shooting and sound design.

The effect of the folding rear-seat aperture in the acoustic response of a sedan car

“…The pressure distribution is scaled in the 40-100 dB interval, where the black full circle indicates the location of the microphone. These plots show the acoustic responses of the cavity subjected to the operational forces calculated using equation (20).…”

“…The operational forces are calculated experimentally, using the matrix inversion method. 20 A coupled vibro-acoustic model is constructed by imposing a Neumann-type boundary condition. The coupled vibro-acoustic problem is solved using the modally reduced Eulerian displacement–pressure formulation.…”

Low-noise structure optimization of a heavy commercial vehicle cab based on approximation model

“…6 In addition, this band is mainly caused by engine idle speed and road roughness, However, conventional reduction measures of sound absorption have less effect under this frequency band. 7 Low-noise structure design within this frequency band has attracted considerable attention. In general, lownoise structure optimization can reduce the vibration amplitudes and velocities of panels and consequently improve acoustic comfort.…”

“…6 In addition, this band is mainly caused by engine idle speed and road roughness, However, conventional reduction measures of sound absorption have less effect under this frequency band. 7…”

Improved vehicle interior structure-borne noise induced by the powertrain using parallel dry friction damper

“…For the analysis, several multichannel measurements, containing synchronous data for structure-and air-borne sound, in different operating conditions were performed. 1 The transfer functions calculated from an engine run-up measurement were used to analyze the contributions of the main sound sources over the dominant transfer paths to the vehicle interior noise. 2 In addition, the excitation from the main source was altered while all other aspects of source and structure were kept the same.…”