This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Diagnostics of Engine Noise During Run-up Using HELS Based Nearfield Acoustical Holography
Technical Paper
2005-01-2505
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
This paper describes the diagnostics of noise sources and characteristics of a full-size gasoline engine during its run-up using Helmholtz Equation Least Squares (HELS) method based nearfield acoustical holography (NAH). The acoustic pressures are measured using an array of 56 microphones conformal to the contours of engine surfaces at very close range. Measurements are collected near the oil pan, front and intake sides. The data thus collected are taken as input to HELS program, and the acoustic pressure mappings on the oil pan, front and intake surfaces are calculated. These reconstructed acoustic quantities clearly demonstrate the “hot spots” of sound pressures generated by this gasoline engine during its run-up and under a constant speed condition. These acoustic pressure mappings together with order-tracking spectrograms allow for identification of the peak amplitudes of acoustic pressures on a targeted surface as a function of the frequency and engine rpm. This information enables one to correlate a particular drive train order at a specific frequency and rpm to the peak amplitude of the sound pressure at a specific location on the engine surface, e.g., an oil pan. The depth and breadth of clearly defined information obtained can be very helpful to identify noise sources and how they change with the engine speed.
Recommended Content
Authors
Citation
Abualfeilat, A., Chevalier, S., Tabbert, D., Moondra, M. et al., "Diagnostics of Engine Noise During Run-up Using HELS Based Nearfield Acoustical Holography," SAE Technical Paper 2005-01-2505, 2005, https://doi.org/10.4271/2005-01-2505.Also In
References
- Wang Z. Wu S. F. “Helmholtz equation-least-squares method for reconstructing the acoustic pressure field,” Journal of the Acoustical Society of America 102 2020 2032 1997
- Wu S. F. “On reconstruction of acoustic pressure fields using the Helmholtz equation least squares method,” Journal of the Acoustical Society of America 107 2511 2522 2000
- Wu S. F. “Hybrid nearfield acoustic holography,” Journal of the Acoustical Society of America 115 1 207 217 2004
- Schenck H. A. “Improved integral formulation for acoustic radiation problems,” Journal of the Acoustical Society of America 44 41 58 1968
- Williams E. G. Maynard J. D. “Holographic imaging without the wavelength resolution limit,” Physics Review Letters 45 554 557 1980
- Williams E. G. Maynard J. D. Skudrzky E. “Sound source reconstructions using a microphone array,” Journal of the Acoustical Society of America 68 340 344 1980
- Williams E. G. Dardy H. D. Fink R. G. “Neafield acoustical holography using an underwater automated scanner,” Journal of the Acoustical Society of America 78 789 798 1985
- Borgiotti G. V. Sarkissian A. Williams E. G. Schuetz L. “Conformal generalized near-field acoustic holography for axisymmetric geometries,” Journal of the Acoustical Society of America 88 199 209 1990
- Gardner B. K. Bernhard R. J. “A noise source identification technique using an inverse Helmholtz integral equation method,” ASME Journal of Vibration, Acoustics, Stress, and Reliability in Design 110 84 90 1988
- Kim G.- T. Lee B.- T. “3-D sound source reconstruction and field reproduction using the Helmholtz integral equation,” Journal of Sound and Vibration 136 245 261 1990
- Bai M. R. “Application of BEM (boundary element method)-based acoustic holography to radiation analysis of sound sources with arbitrarily shaped geometries,” Journal of the Acoustical Society of America 92 533 549 1992
- Isakov V. Wu S. F. “On theory and applications of the HELS method in inverse acoustics,” Inverse Problem 18 1147 1159 2002
- Rayess N. E. Wu S. F. “Experimental validations of the HELS method for reconstructing acoustic radiation from a complex vibrating structure,” Journal of the Acoustical Society of America 107 2955 2964 2000
- Wu S. F. Rayess N. Zhao X. “Visualization of acoustic radiation from a vibrating bowling ball,” Journal of the Acoustical Society of America 109 2771 2779 2001
- Wu S. F. Yu J. “Reconstructing interior acoustic pressure field via Helmholtz equation least-squares method,” Journal of Acoustical Society of America 104 2054 2060 1998
- Moondra M. Wu S. F. “Visualization of vehicle interior noise using HELS based NAH,” Noise Control Engineering Journal