Engine noise source breakdown - Theory, simulation and results

1981 ◽  
Author(s):  
B. TESTER ◽  
M. FISHER
Keyword(s):  
Noise Source ◽  
Engine Noise

Acoustic Double Holography Method and its Application to Engine Noise Research

1997 ◽  
Author(s):  
Milsuo Nakano ◽  
Masao Nagamatsu ◽  
Kohei Suzuki ◽  
Takuya Yoshimura
Keyword(s):  
Noise Source ◽  
Near Field ◽  
Wave Length ◽  
Pressure Data ◽  
Acoustic Holography ◽  
Engine Noise ◽  
Simplified Approach ◽  
Noise Shielding ◽  
Full Load Operation ◽  
Control Work

Abstract The acoustic holography (AH) method with single measuring plane has been well known as the conventional method and can be implemented by far field measurement with simple instruments. However, the noise source resolution of the AH is not sufficient. In order to improve the resolution in the noise source identification, several kinds of the acoustic holography methods have been so far proposed. For example, the near field acoustic holography (NAH) can provide high and accurate resolution of the holography by the nearfield measurement. However, the nearfield measurement within one wave length is sometimes impossible in the actual circumstances. The Acoustic Double Holography (A D H) proposed in this paper is a simplified approach with higher resolution of the noise source locations than that of the conventional AH methods. The ADH method basically uses dual measuring planes and does not require nearfield measurement. The sound pressure data detected on the rear plane are transformed into the virtual pressure data on the front plane taking into account of the distance between the plane and the object. Comparing the virtual pressure data with the actual data measured on the front plane, resolution on holography can be improved significantly. Computer simulation and an experiment with two loud speakers were executed in order to confirm the fundamental feature of the proposed method. Several advantages on the method with respect to resolution over the conventional AH method were discussed. Furthermore, the ADH measurement was carried out on running engine under the full load operation. Through these results, the highly noise radiating areas on the engine surface were detected and reduced with noise shielding material. The overall engine noise level was reduced by 1.5dBA as the first stage in this noise control work.

The Identification of Engine Noise Source Based on Simulink Blind Sources Separation

2011 ◽  
Vol 328-330 ◽  
pp. 2134-2139
Author(s):  
Jun Wen Gao ◽  
Yan Ming Quan ◽  
Yong Man Lin
Keyword(s):  
Noise Source ◽  
Experimental Testing ◽  
Blind Separation ◽  
Engine Noise ◽  
Noise Sources ◽  
New Approach ◽  
Testing Platform ◽  
Simulink Model ◽  
Separation Theory ◽  
Surface Noise

AC algorithm of blind sources has been applied to the identification of engine noise sources. However, the testing platform based on the blind separation theory is difficult to actualize some experiments and obtain data in the real environment, or to obtain these requires high cost. Therefore, this paper proposes a new approach to construct an experimental testing platform-Sinmulink Model so as to identify engine surface noise sources. This model is applied to the test of the experimental data. These experiments demonstrate that Simulink model is efficient to identify engine noise source and the testing data accord with that made by the former platform. It is obvious that Simulink model, to some degree, can be used to replace engine surface noise sources testing platform.

Paper 8: The Diesel Engine as a Source of Commercial Vehicle Noise

1969 ◽  
Vol 184 (16) ◽  
pp. 63-72 ◽  
Author(s):  
P. E. Waters ◽  
N. Lalor ◽  
T. Priede
Keyword(s):  
Diesel Engine ◽  
Empirical Formula ◽  
Engine Speed ◽  
Commercial Vehicle ◽  
Noise Source ◽  
The Other ◽  
Commercial Vehicles ◽  
Engine Noise ◽  
Vehicle Noise ◽  
Road Speed

The drive-past noise of diesel-engined commercial vehicles is controlled by engine speed rather than road speed. The principal noise source related to the power unit is the noise radiated by the engine structure, which has a level of 85–91 dBA during the ISO test. The combined intensity of all the other such sources is, at the most, equal to the noise radiated by the structure. It has been found that the parameters controlling engine noise are the bore, speed, and combustion systems. This has led to an empirical formula which predicts engine noise to within ±2 dBA.

scholarly journals Diesel Engine Noise Source Visualization with Wideband Acoustical Holography

2017 ◽  
Author(s):  
Tongyang Shi ◽  
Yangfan Liu ◽  
J Stuart Bolton ◽  
Frank Eberhardt ◽  
Warner Frazer
Keyword(s):  
Diesel Engine ◽  
Noise Source ◽  
Engine Noise ◽  
Acoustical Holography
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