Dependence of combustion dynamics in a gasoline engine upon the in-cylinder flow field, determined by high-speed PIV

2012 ◽  
Vol 53 (6) ◽  
pp. 1701-1712 ◽  
Author(s):  
M. Buschbeck ◽  
N. Bittner ◽  
T. Halfmann ◽  
S. Arndt
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Gasoline Engine ◽  
Combustion Dynamics ◽  
Cylinder Flow

scholarly journals Simultaneous In-Cylinder Flow Measurement and Flame Imaging in a Realistic Operating Engine Environment Using High-Speed PIV

2019 ◽  
Vol 9 (13) ◽  
pp. 2678 ◽  
Author(s):  
Atsushi Nishiyama ◽  
Minh Khoi Le ◽  
Takashi Furui ◽  
Yuji Ikeda
Keyword(s):  
Flow Field ◽  
Flame Front ◽  
Flame Propagation ◽  
High Speed ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Front Propagation ◽  
Growth Direction ◽  
Flame Imaging ◽  
Cylinder Flow

Among multiple factors that affect the quality of combustion, the intricate and complex interaction between in-cylinder flow/turbulent field and flame propagation is one of the most important. In this study, true simultaneous, crank-angle resolved imaging of the flame front propagation and the measurement of flow-field was achieved by the application of high-speed Particle Image Velocimetry (PIV). The technique was successfully implemented to avoid problems commonly associated with PIV in a combustion environment, such as interferences and reflections, avoided thanks to a number of adjustments and arrangements. All experiments were carried out inside a single-cylinder optical gasoline engine operated at 1200 rpm, using port fuel injection (PFI) with stoichiometric mixtures. It was found that the global vortex location of the tumble motion heavily influences the flame growth direction as well as the flame shape, mainly due to the tumble-induced flow across the ignition source. The flame propagation also influences the flow-field such that the pre-ignition flow can be maintained and the flow of unburned region surrounding the flame front will be enhanced.

Classifying IC Engine Swirl Fields by Complex Moments

2019 ◽  
Author(s):  
Kwee-Yan Teh ◽  
Penghui Ge ◽  
Fengnian Zhao ◽  
David L. S. Hung
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
High Speed ◽  
Flow Fields ◽  
Flow Patterns ◽  
Analysis Approach ◽  
Flow Mode ◽  
Mean Velocity ◽  
Ic Engine ◽  
Cylinder Flow

Abstract Engine in-cylinder flow varies from cycle to cycle, which contributes to variation of the mixing and combustion processes between fuel and air. Such flow field cyclic variability at the macroscopic scale is distinct from random fluctuations at the microscopic scale about the ensemble mean velocity field due to turbulence. At the extreme, the mean velocity field may bear no resemblance to any instantaneous flow field within the ensemble. Rather, these instantaneous fields may appear multimodal. Yet previous attempts to define and identify the flow modes were either qualitative (by visual inspection), or based on strict point-by-point velocity difference between two flow fields. The former approach is clearly subjective; the latter does not accommodate translational and rotational variations of in-cylinder flow patterns relative to a flow mode. Such spatial variations, in location and orientation, of the flow patterns can be quantified by the technique of complex moment normalization. The algebraic properties of complex moments are also intimately related to the geometric and physical properties of two-dimensional/two-component flow fields. In this paper, we take the normalized moments as flow field attributes for further cluster analysis. This analysis approach is demonstrated using a set of in-cylinder flow fields obtained by high-speed particle image velocimetry on a swirl plane of a research optical engine operating under low intake swirl setting. The resulting classification of the flow fields into several clusters (flow modes) are discussed, and the potential and limitations of the analysis approach are appraised.

Flow and Mixture Distribution in a High-Speed Five-Valve Direct Injected Gasoline Engine

2006 ◽  
Vol 7 (2) ◽  
pp. 143-166 ◽  
Author(s):  
N Kampanis ◽  
C Arcoumanis ◽  
S Kometani ◽  
R Kato ◽  
H Kinoshita
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Gasoline Engine ◽  
Flow Instability ◽  
Direct Injection ◽  
Mixture Distribution ◽  
Direct Injection Engines ◽  
Planar Laser ◽  
Performance And Emissions ◽  
Cylinder Flow

The in-cylinder flow, spray dynamics, air-spray interaction, and fuel vapour distribution have been characterized in a motorcycle five-valve gasoline engine in terms of their effect on performance and emissions. A five-valve single-cylinder optical engine was employed which operated at speeds up to 3000 r/min in the close spacing configuration, with an early induction injection strategy using a centrally mounted swirl pressure atomizer. Particle image velocimetry, spray imaging in a spray chamber and in the engine, and planar laser-induced fluorescence revealed the importance of a strong and ordered in-cylinder flow for the efficient distribution of the liquid fuel throughout the cylinder volume and its complete evaporation prior to combustion, especially in the relatively low speed regime investigated. Furthermore, in the absence of a large-scale vortex structure during compression, incomplete mixing may still occur, resulting in mixture inhomogeneities and flow instability. Consequently, in contrast to port fuel injected engines, where good mixing could be achieved at high revolution rates, even with an unstructured flow, in direct injection engines an ordered flow structure is a prerequisite for efficient combustion and low exhaust emissions.

scholarly journals He misfire degree and its effects on combustion and pollutant formation of subsequent cycles: A study on a high speed gasoline engine

2021 ◽  
pp. 292-292
Author(s):  
Yangyang Chen ◽  
Qifei Jian ◽  
Banglin Deng ◽  
Kaihong Hou
Keyword(s):  
Flow Field ◽  
Flame Propagation ◽  
High Speed ◽  
Gasoline Engine ◽  
Working Process ◽  
No Emission ◽  
Pollutant Formation ◽  
Combustion Phase ◽  
Lower Temperature ◽  
Final Amount

Misfire has attracted lots of researcher?s attention as a common engine fault, but most researchers focus on misfire diagnosis. For motorcycle engines, misfire is more worth to investigate because of the more extensive operation windows. The misfire degree is detected by experiment and its effect mechanism on subsequent cycles is investigated through simulation. Its effect is analyzed through two aspects: 1) misfire cycle leaves about 10.8% fuels that participate in next cycle working process, leading to richer fuel/air mixture. But 13.8 % lower of in-cylinder peak pressure than normal scenario is observed. Then interaction between flame propagation and flow field is discussed. The effect of misfire on flow field intensity is small, but it changes flow field structure largely. This change evolves persistently during subsequent processes, superimposing the lower temperature brought by misfire of last cycle, resulting in slower flame propagation and thus lower thermal efficiency for misfire scenario. This impact can last 3-4 subsequent cycles until gradually fades away; 2) for pollutants formations, the NO emission is lower for misfire scenario due to the lower in-cylinder temperature, but HC emission is higher. Although higher CO is produced during main combustion phase for misfire scenario, it converts to CO2 more largely during post flame stage, resulting in almost the same final amount relative to normal scenario.

Characterization of flow field and combustion dynamics in a novel pressurized side-wall quenching burner using high-speed PIV/OH-PLIF measurements

2022 ◽  
Vol 94 ◽  
pp. 108921
Author(s):  
Pascal Johe ◽  
Florian Zentgraf ◽  
Max Greifenstein ◽  
Matthias Steinhausen ◽  
Christian Hasse ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Side Wall ◽  
Combustion Dynamics

scholarly journals The Relationship between In-Cylinder Flow-Field near Spark Plug Areas, the Spark Behavior, and the Combustion Performance inside an Optical S.I. Engine

2019 ◽  
Vol 9 (8) ◽  
pp. 1545 ◽  
Author(s):  
Atsushi Nishiyama ◽  
Minh Khoi Le ◽  
Takashi Furui ◽  
Yuji Ikeda
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Entire Area ◽  
Combustion Performance ◽  
Simultaneous Imaging ◽  
Spark Plug ◽  
Combustion Duration ◽  
Image Velocimetry ◽  
Flame Development ◽  
Cylinder Flow

The stringent regulations that were placed on gasoline vehicles demand significant improvement of the powertrain unit, not only to become cleaner but also more efficient. Therefore, there is a strong need to understand the complex in-cylinder processes that will have a direct effect on the combustion quality. This study applied multiple high-speed optical imaging to investigate the interaction between the in-cylinder flow, the spark, the flame, and combustion performance. These individual elements have been studied closely in the literature but the combined effect is not well understood. Simultaneous imaging of in-cylinder flow and flame tomography using high-speed Particle Image Velocimetry (PIV), as well as simultaneous high-speed spark imaging, were applied to port-injected optical gasoline imaging. The captured images were processed using in-house MATLAB algorithms and the deduced data shows a trend that higher in-cylinder flow velocity near the spark will increase the stretch distance of the spark and decrease the ignition delay. However, these do not have much effect on the combustion duration, and it is the flow-field in the entire area surrounding the flame development that will influence how fast the combustion and flame growth will occur.

Subgrid-scale backscatter in reacting and inert supersonic hydrogen–air turbulent mixing layers

2014 ◽  
Vol 743 ◽  
pp. 554-584 ◽  
Author(s):  
J. O’Brien ◽  
J. Urzay ◽  
M. Ihme ◽  
P. Moin ◽  
A. Saghafian
Keyword(s):  
Mach Number ◽  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Mixing ◽  
High Speed ◽  
Large Scale ◽  
Eddy Viscosity ◽  
Mixing Layers ◽  
Subgrid Scale ◽  
Combustion Dynamics

AbstractThis study addresses the dynamics of backscatter of kinetic energy in the context of large-eddy simulations (LES) of high-speed turbulent reacting flows. A priori analyses of direct numerical simulations (DNS) of reacting and inert supersonic, time-developing, hydrogen–air turbulent mixing layers with complex chemistry and multicomponent diffusion are conducted here in order to examine the effects of compressibility and combustion on subgrid-scale (SGS) backscatter of kinetic energy. The main characteristics of the aerothermochemical field in the mixing layer are outlined. A selfsimilar period is identified in which some of the turbulent quantities grow in a quasi-linear manner. A differential filter is applied to the DNS flow field to extract filtered quantities of relevance for the large-scale kinetic-energy budget. Spatiotemporal analyses of the flow-field statistics in the selfsimilar regime are performed, which reveal the presence of considerable amounts of SGS backscatter. The dilatation field becomes spatially intermittent as a result of the high-speed compressibility effect. In addition, the large-scale pressure-dilatation work is observed to be an essential mechanism for the local conversion of thermal and kinetic energies. A joint probability density function (PDF) of SGS dissipation and large-scale pressure-dilatation work is provided, which shows that backscatter occurs primarily in regions undergoing volumetric expansion; this implies the existence of an underlying physical mechanism that enhances the reverse energy cascade. Furthermore, effects of SGS backscatter on the Boussinesq eddy viscosity are studied, and a regime diagram demonstrating the relationship between the different energy-conversion modes and the sign of the eddy viscosity is provided along with a detailed budget of the volume fraction in each mode. A joint PDF of SGS dissipation and SGS dynamic-pressure dilatation work is calculated, which shows that high-speed compressibility effects lead to a decorrelation between SGS backscatter and negative eddy viscosities, which increases for increasingly large values of the SGS Mach number and filter width. Finally, it is found that the combustion dynamics have a marginal impact on the backscatter and flow-dilatation distributions, which are mainly dominated by the high-Mach-number effects.

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