On the prediction of impact noise, part VIII: Diesel engine noise

doi:10.1016/S0022-460X(85)80101-2

Journal of Sound and Vibration

Volume 102, Issue 1, 8 September 1985, Pages 21-56

https://doi.org/10.1016/S0022-460X(85)80101-2 Get rights and content

The noise energy radiated from a diesel engine due to combustion and piston slap excitation is investigated by considering single impacts. From the results obtained, possible methods of noise control are studied, and the expected results due to changes in the liner mounting to the engine frame, and the bearings of the camshaft for an injected engine, are compared to the measured noise levels. This proves to be very successful and radical modifications in the engine for noise control can be investigated in this way prior to full development of the prototype engine.

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There are more references available in the full text version of this article.

Cited by (14)

Coupling effect of shaft torsional vibration and advanced injection angle on medium-speed diesel engine block vibration
2023, Engineering Failure Analysis
Engine body vibration is an important safety concern for diesel engines as it can lead to severe engine damages and even catastrophic failures. Traditional methods for excitation computation assume that the rotational speed and the cylinder pressure remain stable under each working cycle, which makes it impossible to precisely predict vibration peaks at certain frequencies. But in practice, the existence of shafting torsional vibration will lead to the fluctuation of rotational speed and cylinder pressure. To predict engine block vibration more accurately, this paper proposes a novel method considering the instantaneous variations in rotational speed and cylinder pressure. It is implemented by two steps. Firstly, an innovative model considering the coupling effect between shaft torsional vibration and advanced injection angle is proposed, it particularly explains how the cylinder pressure and instantaneous rotational speed vary due to the coupling effects. Secondly, the excitation forces that cause block vibration are analyzed and their computational formulas are improved. This method also considers the offset of excitation loading position caused by torsional vibration. The coupling model is experimentally verified and the excitations are loaded into a finite element model of the diesel engine for vibration response prediction. The results reveal that the coupled model can predict vibration peaks at sideband frequencies and thus makes the frequency spectrum much richer than that of the traditional method. Furthermore, it shows that the acceleration results obtained by the coupled model have better prediction accuracy than those obtained from traditional methods, with the deviation percentage reducing from 6.31% and 8.41% to 0.64% and 0.32% in the X and Z direction. It indicates that the coupled model is more reliable in predicting the vibration response of the engine block. Finally, the effect of advanced injection angle on engine block vibration is investigated and the optimal value of the advanced injection angle is determined to be 29 CA, which makes the engine block vibration reduced by 3.60%, 2.72%, and 3.16% in the X, Y, and Z direction comparing to the original advanced injection angle. Overall, this study presents an improved approach for predicting engine block vibrations and offers valuable insights for the design of shafting structures and fuel injection parameters in marine diesel engines.
Engine noise characterisation with Wigner-Ville time-frequency analysis
1993, Mechanical Systems and Signal Processing
Reduction in the sound emitted by engines requires accurate identification of the excitation and propagation mechanisms inside the engine. Time-frequency analysis of vibration signals picked up on the outside and inside of an engine cylinder enables us to link every event observed in the time-frequency plane to one excitation source. It is then possible to measure the energy of each event and to quantify the part of each excitation mechanism in the vibration energy which is emitted towards the outside of the engine.
On the prediction of impact noise, X: The design and testing of a quietened drop hammer
1986, Journal of Sound and Vibration
Part V in this series showed that the technique of predicting overall noise levels (L_eq per event) from vibration levels in a drop hammer produces surprisingly accurate results, allowing a good estimate of the contribution of each component to the overall noise. An exact one-third scale replica of an existing drop hammer was built for experimental purposes. On this particular drop hammer acceleration noise and ringing noise were both shown to be significant in terms of energy, unlike most other impact-related machinery noise, where ringing noise dominates. The work reported in this paper concerns a second model drop hammer which has replaced the first, incorporating maximized damping and isolation to reduce ringing noise. Predicted noise energy levels have been compared with measured noise energy levels at each stage of development, and the agreement between the two is consistently good. Reductions in noise of 6 dB(A L_eq) have been obtained without modifying the basic tup design. Ringing noise becomes insignificant with maximum isolation and damping, this being confirmed by vibration measurements. The magnitude and spectral shape of the energy is very similar to acceleration noise theoretically derived by using tup volume and die-to-die contact times. The noise from the anvil becomes negligible when a close sand-filled aluminium surround is fitted. Further reductions of noise have been achieved by softening the die-to-die blows and thus reducing the acceleration noise from the tup. This has been done with damping plungers on either side of the dies, and the noise levels in L_eq per blow have been reduced a further 15 dB(A). This is presented as a logical progression in our noise reduction programme rather than as a real solution to a practical problem, and as such is an advancement in our knowledge of drop hammer noise.
Modification of impact sound by adjusting the excitation input for comfortable design of punch press machine sound
2015, Noise Control Engineering Journal
Calculation analysis of vibration signal characteristic parameter of diesel engine block structure
2015, Neiranji Gongcheng/Chinese Internal Combustion Engine Engineering
Signal Patterns of Piston Slap of a Four-Cylinder Diesel Engine
2015, Lecture Notes in Mechanical Engineering

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^†: This work was performed while the author was at the Institute of Sound and Vibration Research, University of Southampton.

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On the prediction of impact noise, part VIII: Diesel engine noise

Journal of Sound and Vibration

Journal of Sound and Vibration

Journal of Sound and Vibration

Journal of Sound and Vibration

Source identification on a diesel engine using acoustic intensity measurements

Noise Control Engineering

An engineering approach to diesel truck noise reduction

Society of Automotive Engineers Paper No. 730713

Reduction of noise emissions from diesel engine surfaces

Society of Automotive Engineers Paper No. 720135