Characteristics of Early Flame Development in a Direct-Injection Spark-Ignition CNG Engine Fitted with a Variable Swirl Control Valve

Aziz, Abdul; Anbese, Yohannes Tamirat; Hagos, Ftwi Yohaness; Heikal, Morgan; Firmansyah, Firmansyah

doi:10.3390/en10070964

Cited by 9 publications

(5 citation statements)

References 26 publications

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“…The maximum degree of wrinkles is observed in the early flames in the homogeneous charge combustion with an engine speed of 1500 rpm. The fact that the local fuel-air ratio of the mixture is richer or close to stoichiometric near the spark electrode region with a stratified charge, the degree of wrinkles tends to increase with an increase in engine speed [27].…”

Section: Analysis and Discussionmentioning

confidence: 99%

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Application of The Chain Code and Fourier Analysis Techniques for The Investigation of Wrinkles and Distortions on Early Flames

Aziz

Hagos

Anbese

et al. 2018

IJAME

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The study of flame commencement and growth in SI engine has attracted the attention of many researchers due to its strong dependence to the in-cylinder flow and its capability to influence flame propagation characteristics in SI engines. Optical visualisation has been one of the prominent techniques utilized in this study of the early flame properties. This work shows the application of Elliptic Fourier analysis (EFA) and image processing tools for the investigation of the early flame details from its shape features. An endoscopic ICCD camera was used to capture the flame images, at an interval of 2° CA starting from ignition onset for a period of 30° CAs (about 3 ms), from a CNG DI single cylinder SI engine operation in stratified and homogeneous charge conditions. The intake configuration was adjusted to acquire tumble or swirl induction, and engine speed was made to vary between 1500 and 2100 rpm. The sequences of collected images were processed to investigate wrinkles, distortion and growth rate of the early flame within the 3 ms combustion duration. Some tools of image processing, such as intensity enhancement, filtering, thresholding and boundary tracing, were applied. Once the flame boundary identified, it was chain coded, and elliptic Fourier function was utilised to characterise the contour. For this purpose, a computer programming code was proposed by the authors for automatic processing of the flame image data. The application of the elliptic Fourier analysis was found useful in the investigation of the early flame characteristics from its shape features; led to the portrayal of wrinkles and distortion levels quantitatively in a simpler way.

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Section: Analysis and Discussionmentioning

confidence: 99%

“…Eight-directional Freeman chain code and depiction of the typical boundary of an image expressed by the code 22212070006675455433[27].…”

mentioning

confidence: 99%

Application of The Chain Code and Fourier Analysis Techniques for The Investigation of Wrinkles and Distortions on Early Flames

Aziz

Hagos

Anbese

et al. 2018

IJAME

Self Cite

View full text Add to dashboard Cite

show abstract

“…Lean combustion strategy works under both homogeneous and stratified charge depending on the extent of leanness. When the overall air-fuel ratio is maintained extremely lean, near to the lower flammability limit, the probability of an ignited mixture having a sustained flame is small [203]. In such cases, the strategy is mainly modified to have a fuel-stratification mechanism, so that a variable air-fuel ratio occurs around the combustion chamber.…”

Section: Effect Of Lean Charge Strategymentioning

confidence: 99%

“…Among the engine hardware-based studies, intake and exhaust valve-lift optimization is believed to enhance the combustion characteristics, engine performance, and emissions of CNG-fueled engines. Optimization of the intake and exhaust valve lift contributes to the extent of turbulence on the engine mainly during the early flame-development stage, leading to a sustained flame and stable combustion [203,229]. Soid et al [230] numerically investigated the effect of different valve timings on the performance of a methane-fueled small engine.…”

Section: Effect Of Valve Lift and Valve Timingmentioning

confidence: 99%

Natural Gas Engine Technologies: Challenges and Energy Sustainability Issue

2018

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Energy sustainability and environmental issues pose greater challenges on different primary energy sectors as the global energy demand increases and it is projected to further increase with an upsurge in population. On the other hand, energy sources from conventional fossil-based fuels are depleting, forcing explorations in challenging and difficult locations. As a result, the use of alternative fuels received dramatic consideration to substitute these conventional fuels, of which natural gas took the significant share. However, the share of natural-gas vehicles in the current vehicle market is quite small, and it is estimated to be below 5%. This paper reviews the current resource scenarios including proven and potential reserves, current production, and consumption, along with the fueling infrastructure, distribution, and storage. It also provides summary of the development of fuel-injection technologies aimed to enhance the performance of gas engines. More attention was also given to natural-gas engines and their limitations. Parameters affecting the performance and combustion of compressed natural gas (CNG) in spark-ignition (SI) engines are thoroughly assessed, among which compression ratio and injection timing play major roles in the optimization of CNG-fueled engines. Furthermore, different technologies that help close the performance gap between conventional liquid-fuel and natural-gas engines and future directions of the research are presented.

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“…Natural Gas (NG) is considered as an appropriate alternative for internal combustion engines due to its cleaner combustion, relative lower cost and rich reserves [1,2]. It is generally applied in the form of mono-or dual-fuel engines, such as spark ignition natural gas engines, natural gas/diesel engines and CNG-H 2 engines [3][4][5]. For spark ignition (SI) natural gas engines, the further thermal efficiency improvement is constrained by a knocking phenomenon that commonly occurs in gas-fueled SI engines [6].…”

Section: Introductionmentioning

confidence: 99%

A Two-Zone Combustion Model for Knocking Prediction of Marine Natural Gas SI Engines

2018

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The further thermal efficiency improvement of marine natural gas engine is constrained by a knocking phenomenon that commonly occurs in gas-fueled spark-ignited engines. It plays an important role to investigate how the knocking occurs and how to predict it based on the engine simulation model. In this paper, a two-zone model is developed to provide the prediction of knocking performance and NO emission, which is verified by engine test bed data from a transformed marine natural gas spark ignition (SI) engine. Cylindrical division theory is used to describe the shape of the two zones to decrease the computational cost, as well as a basic mechanism for NO concentration calculation. In order to solve the volume balance, three boundary parameters are introduced to determine the initial condition and mass flow between the two zones. Furthermore, boundary parameters' variation and knocking factor (compression ratio and advanced ignition angle) will be discussed under different working conditions. Result shows that the two-zone model has sufficient accuracy in predicting engine performance, NO emission and knocking performance. Both the increasing compression ratio and advanced ignition angle have a promoting effect on knocking probability, knocking timing and knocking intensity. The knocking phenomenon can be avoided in the targeted natural gas SI engine by constraining the compression ratio smaller than 14 and advanced ignition angle later than 30 • before top dead center (BTDC).Energies 2018, 11, 561 2 of 23 Two broad categories of experimental based methods are used to detect the knocking phenomenon in a certain natural gas engine: the former one is based on direct measurement, like an intensified charge coupled detector (ICCD) camera and Laser-induced Fluorescence (LIF) imaging [8,9]; other methods [10,11] are based on indirect measurement such as in-cylinder pressure analysis, cylinder block vibration, exhaust gas temperature, etc. On the other hand, simulation models enable engineers to explore the details comprehensively during the design period in order to determine the best case, saving research time and development cost. In general, numerical simulation of the natural gas engine working process is classified as follows: the mean value model, zero-dimensional model, quasi-dimensional model and multi-dimensional model [12]. The mean value model is not primarily intended for engine development, but it is efficient for integrated system research, thus it is usually based on a large amount of engine test data and has scarcely no ability to predict [13,14]. For knocking prediction simulation models, the main objective is to characterize the end-gas temperature, which has a direct effect on knocking occurring. It is difficult for the zero-dimensional model to achieve this goal since the in-cylinder temperature and species concentrations are assumed to be uniform throughout the cylinder [15]. The multi-dimensional simulation model (or Computational Fluid Dynamics model, CFD) provides most details of in-cylinder para...

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Characteristics of Early Flame Development in a Direct-Injection Spark-Ignition CNG Engine Fitted with a Variable Swirl Control Valve

Cited by 9 publications

References 26 publications

Application of The Chain Code and Fourier Analysis Techniques for The Investigation of Wrinkles and Distortions on Early Flames

Application of The Chain Code and Fourier Analysis Techniques for The Investigation of Wrinkles and Distortions on Early Flames

Natural Gas Engine Technologies: Challenges and Energy Sustainability Issue

A Two-Zone Combustion Model for Knocking Prediction of Marine Natural Gas SI Engines

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