On the solving method of the indirect source characteristics identification model for an engine exhaust system based on error estimation
LIU Haitao1,2 LIAN Xiaomin 2 LIU Linya 1
1. School of Railway Tracks and Transportation, East China Jiaotong University, Nanchang Jiangxi 330013, China;
2. State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
Abstract:Linear time-invariant hypothetical model solved in the frequency domain for the determination of engine source characteristics, may still play a practical role in the engine exhaust system design. However, the existing methods for solving the model remain that error is large, the results are sensitive to input error, and the process of identifying and solving are complicated and other issues. In order to improve the accuracy of engine source characteristics identification, error estimation method was established for the indirect identification model, namely source strength level dispersion estimation and source impedance deviation estimation. The equation from the over-determined nonlinear equations in the identification model was pairwise combined, which were directly solved by analytic geometry method. Multiple source characteristic parameter solutions were obtained, and then the optimal solution was selected by the source impedance deviation estimation. According to analysis and calculation, the error value of the source characteristic parameters acquired by the method above, is significantly lower than the traditional four load method. Finally, the three-dimensional coupled simulation of acoustic and flow method was used to verify the results of source characteristic identification. The sound pressure level of far-field response point predicted by simulation agrees well with the experimental results, which indicates that the optimal source characteristic parameters selection method based on error estimation can obtain more accurate source identification results, and can efficiently reduce the identification error and complexity.
刘海涛1,2,连小珉2,刘林芽1. 基于误差估计的发动机排气声源特性间接识别模型求解方法研究[J]. 振动与冲击, 2016, 35(16): 91-98.
LIU Haitao1,2 LIAN Xiaomin 2 LIU Linya 1 . On the solving method of the indirect source characteristics identification model for an engine exhaust system based on error estimation. JOURNAL OF VIBRATION AND SHOCK, 2016, 35(16): 91-98.
[1] DOKUMACI E. Prediction of source characteristics of engine exhaust manifolds[J]. Journal of Sound and Vibration, 2005, 280(3-5): 925-942.
[2] 刘海涛,郑四发,康钟绪,等.基于四负载方法的汽车发动机排气源特性研究[J].振动工程学报,2011,24(5):573-577.
LIU Hai-tao, ZHENG Si-fa, KANG Zhong-xu, LIAN Xiao-min. Acoustical source characteristics of vehicle exhuast system based on the four-load method[J]. Journal of Vibration Engineering, 2011, 24(5):573-577.
[3] BODEN H. The multiple load method for measuring the source characteristics of time-variant sources[J]. Journal of Sound and Vibration, 1991, 148(3): 437-453.
[4] RAMMAL H, BODEN H. Modified multi-load method for nonlinear source characterisation[J]. Journal of Sound and Vibration, 2007, 299(4-5): 1094-1113.
[5] MACIAN V, TORREGROSA A J, BROATCH A. A view on the internal consistency of linear source identification for I.C engine exhaust noise prediction[J]. Mathematical and Computer Modelling, 2013, 57(7-8): 1867-1875.
[6] GALAITISIS G A, BENDER K E. Measurement of the acoustic impedance of an internal combustion engine[J]. Journal of the Acoustical Society of America, 1975, 58(1): S8.
[7] PARSAD G M, CROCKER J M. Acoustical source characteriztion studies on a multi-cylinder engine exhaust system[J]. Journal of Sound and Vibration, 1983, 90(4): 490-497.
[8] ROSS F D, CROCKER J M. Measurement of the acoustic internal source impedance of an internal combustion engine[J]. Journal of the Acoutical Society of America, 1983, 74(1): 18-27.
[9] DOIGE G A, ALVES S H. Experimental characterization of noise source for duct acoustics[J]. Journal of Vibration and Acoustics, 1989, 111(1): 108-114.
[10] ALVES H S. Characterization of noise sources in ducts[D]. [S.l.]: Canada: The University of Calgary, 1986.
[11] PRASAD G M. A Four load method for evaluation of acoustic source impedance in a duct[J]. Journal of Sound and Vibration, 1987, 114(2): 347-356.
[12] BODEN H. On multi-load methods for determination of the source data of acoustic one-port sources[J]. Journal of Sound and Vibration, 1995, 180(5): 725-743.
[13] JANG H S, IH G J. Refined multiload method for measuring acoustical source characteristics of an intake or exhaust system[J]. Journal of the Acoustical Society of America, 2000, 107(6): 3217-3225.
[14] SRIDHARA S B, CROCKER J M. Error analysis for the four-load method used to measure the source impedance inducts[J]. The Journal of the Acoustical Society of America, 1992, 92(5): 2924-2931.
[15] MUNJAL L M. Acoustic of ducts and mufflers 2th edition[M]. New York: John Wiley, 2014.
[16] RIENSTRA W S. A small strouhal number analysis for acoustic wave-jet flow-pipe interaction[J]. Journal of Sound and Vibration, 1983, 86(4): 539-556.
[17] TIIKOJA H, LAVRENTJEV J, RAMMAL H. Experimental investigations of sound reflection from hot and subsonic flow duct termination[J]. Journal of Sound and Vibration, 2014, 333(3): 788-800.
[18] R.M. Munt, Acoustic transmission properties of a jetpipe with subsonic jet flow: I. the cold jet reflection coefficient[J]. Journal of Sound and Vibration, 1990, 142(3): 413–436.
[19] 徐航手,季振林,康钟绪. 抗性消声器传递损失预测的三维时域计算方法[J]. 振动与冲击,2010, 29(4): 107-110.
XU Hang-shou, JI Zhen-lin, KANG Zhong-xu. Three-dimensional time-domain computational approach for predicting transmission loss of reactive silencers [J]. Journal of vibration and shock, 2010, 29(4): 107-110.