Cycle-To-Cycle variations of Combustion Noise in Diesel

Schmillen, Karl; Wolschendorf, Joachim

doi:10.4271/890129

Cited by 11 publications

(9 citation statements)

References 6 publications

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“…The high in-cylinder pressure of the diesel engine for autoignition caused this increased level of the combustion sound [26,27]. The basic spectrum envelope of the frequency response between combustion and acoustic pressure remains the same for most diesel engines [4,25]. The combustion sound level is proportional to the engine speed in the fixed injection strategy and idle state.…”

Section: Spectral Characteristics Of Engine Soundsmentioning

confidence: 99%

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Artificial Engine Sound Synthesis Method for Modification of the Acoustic Characteristics of Electric Vehicles

Min

Park

2018

Shock and Vibration

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Sound radiation from electric motor-driven vehicles is negligibly small compared to sound radiation from internal combustion engine automobiles. When running on a local road, an artificial sound is required as a warning signal for the safety of pedestrians. In this study, an engine sound was synthesized by combining artificial mechanical and combustion sounds. The mechanical sounds were made by summing harmonic components representing sounds from rotating engine cranks. The harmonic components, including not only magnitude but also phase due to frequency, were obtained by the numerical integration method. The combustion noise was simulated by random sounds with similar spectral characteristics to the measured value and its amplitude was synchronized by the rotating speed. Important parameters essential for the synthesized sound to be evaluated as radiation from actual engines were proposed. This approach enabled playing of sounds for arbitrary engines. The synthesized engine sounds were evaluated for recognizability of vehicle approach and sound impression through auditory experiments.

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Section: Spectral Characteristics Of Engine Soundsmentioning

confidence: 99%

“…Subjective evaluations of various engine sounds were performed in previous studies [2][3][4][5]. Amman and Das [6] proposed deterministic and stochastic components and used synchronous discrete Fourier transform and suboptimal multipulse excitation approaches to generate realistic engine sounds.…”

Section: Introductionmentioning

confidence: 99%

Artificial Engine Sound Synthesis Method for Modification of the Acoustic Characteristics of Electric Vehicles

Min

Park

2018

Shock and Vibration

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“…A variety of studies [22,7] established the origin of CCV in random fluctuations of a wide range of parameters that can alter the combustion process. The modification of the local conditions of the charge [23], the energy transferred to the fluid during the ignition event (in SI engines), the interaction of the flame kernel with the glow-plug electrodes, and also with the combustion chamber walls, are just a few examples in which the turbulence plays an important role.…”

Section: Cyclic Dispersion In Combustionmentioning

confidence: 99%

“…This behaviour is characterized by a non-repeatability of instantaneous cylinder pressure, commonly refereed to as cycle-to-cycle variation or cyclic combustion variability (CCV), caused principally by the cyclic, turbulent and unsteady character of flow and combustion [6]. It unavoidably appears over the whole operation range, indirectly affecting important engine outputs such as performance and acoustics [7,8]. Thus, a proper understanding of the unsteady features of combustion is essential for both identifying the main sources of CCV and minimizing its undesired effects [9,10].…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Cyclical Dispersion in Compression-Ignited Versus Spark-Ignited Engines and Its Significance for Combustion Noise Numerical Modeling

Broatch

López

García-Tíscar

et al. 2018

Journal of Engineering for Gas Turbines and Power

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As noise pollution remains one of the biggest hurdles posed by thermal engines, increasing efforts are made to alleviate the generation of combustion noise from the early design stage of the chamber. Since the complexity of both modern chamber geometries and the combustion process itself precludes robust analytic solutions, and since the resonant, highly three-dimensional pressure field is difficult to be measured experimentally, focus is put on the numerical modeling of the process. However, in order to optimize the resources devoted to this simulation, an informed decision must be made on which formulations are followed. In this work, the experimental cyclic dispersion of the in-cylinder pressure is analyzed in two typical compression-ignited (CI) and spark-ignited (SI) engines. Acoustic signatures and pressure rise rates (PRRs) are derived from these data, showing how while the preponderance of flame front propagation and dependency of previous cycle in SI engine noise usually calls for multicycle, more complex turbulence modeling such as large Eddy simulation (LES), simpler unsteady Reynolds-averaged Navier-Stokes (URANS) formulations can accurately characterize the more consistent pressure spectra of CI thermal engines, which feature sudden autoignition as the main noise source.

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“…Since the combustion phenomenon in each cylinder is approximately periodic [15], it is possible to extract, thanks to the crankshaft turn signal, the pressure evolution of each cycle from the total signal of each cylinder in order to study them separately afterwards. In this way, each one of the approximately 100 cycles recorded for each cylinder at a given engine operating condition is decomposed, in order to obtain more precise information about the incylinder pressure evolution that might allow for a more reliable processing of this signal [6].…”

Section: In-cylinder Pressure Decomposition Techniquementioning

confidence: 99%

New methodology for in-cylinder pressure analysis in direct injection diesel engines—application to combustion noise

Payri

Broatch

Tormos

et al. 2005

Meas. Sci. Technol.

109

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The objective of this paper is to present a new methodology for the analysis of in-cylinder pressure in direct injection (DI) diesel engines. Indeed, for some applications, the traditional study of total pressure is shown to be insufficient and the proposed technique is intended to be an alternative and more efficient tool, since it may provide a better understanding of the physical mechanisms. The main idea is to decompose the in-cylinder pressure evolution according to three phenomena taking place during diesel engine operation: pseudo-motored, combustion and resonance excitation. In order to validate this new method, it is applied to combustion noise analysis. Actually, the combustion process in DI diesel engines may be considered as an important source of noise, and the traditional approach is mainly based on the interpretation of objective overall spectral levels of both in-cylinder pressure and radiated noise, obtained from Fourier analysis. However, this approach has been shown unable to describe all the relevant aspects of the problem, whereas the results obtained from the proposed decomposition technique exhibit a fair qualitative correlation between in-cylinder pressure and combustion noise issues. Further development of this approach could provide a useful tool for the development of optimal injection strategies fulfilling not only performance considerations but also sound quality requirements for combustion noise in DI diesel engines.

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Cycle-To-Cycle variations of Combustion Noise in Diesel

Cited by 11 publications

References 6 publications

Artificial Engine Sound Synthesis Method for Modification of the Acoustic Characteristics of Electric Vehicles

Artificial Engine Sound Synthesis Method for Modification of the Acoustic Characteristics of Electric Vehicles

Experimental Analysis of Cyclical Dispersion in Compression-Ignited Versus Spark-Ignited Engines and Its Significance for Combustion Noise Numerical Modeling

New methodology for in-cylinder pressure analysis in direct injection diesel engines—application to combustion noise

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