Detection of Additives During a Direct Injection Wall Interaction

2021 ◽  
pp. 1-19
Author(s):  
Guillaume L. Pilla ◽  
Julien Sanson
Keyword(s):  
Direct Injection ◽  
Wall Interaction

Phenomenology of Smoke From Direct Injection Diesel Engine

2005 ◽  
Author(s):  
Y. V. Aghav ◽  
P. A. Lakshminarayanan ◽  
M. K. G. Babu ◽  
N. S. Nayak ◽  
A. D. Dani
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Operating Conditions ◽  
Turbulence Structure ◽  
One Dimensional ◽  
Direct Injection Diesel Engine ◽  
Wall Impingement ◽  
Di Diesel Engine ◽  
Dissipation Model ◽  
Wall Interaction

A phenomenological model for smoke prediction from a direct injection (DI) diesel engine is newly evolved from an eddy dissipation model of Dent [1]. The turbulence structure of fuel spray is developed by incorporating the wall impingement to explain smoke formed in free and wall portions. The spray wall interaction is unavoidable in case of modern DI diesel engines of bore less than 125 mm. The new model is one dimensional and based on the recent phenomenological description of spray combustion in direct injection diesel engine. Integration of net soot rate and no need to use empirical tuning constants are the important features, which distinguish the model from existing models. Smoke values are successfully predicted using this model for an engine with heavy-duty applications under widely varying operating conditions.

Analysis of the GDI Spray Dynamics Through Multidimensional Modeling and Flow Visualization in an Optically Accessible SI Engine

2014 ◽  
Author(s):  
Michela Costa ◽  
Ugo Sorge ◽  
Paolo Sementa ◽  
Alessandro Montanaro
Keyword(s):  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Si Engine ◽  
Engine Model ◽  
Working Cycle ◽  
3D Engine ◽  
Experimental Side ◽  
The Difference ◽  
Wall Interaction ◽  
Injection Strategies

Present work is aimed at studying into detail mixture formation and combustion in a gasoline direct injection (GDI) engine working under stoichiometric mixture conditions. The study is performed both numerically and experimentally. From the experimental side, the engine, optically accessible, is characterized by collecting, for various injection strategies, in-cylinder pressure cycles and digital images. From the numerical side, a 3D engine model is developed, that includes proper sub-models for the spray dynamics and the spray-wall interaction. This last phenomenon is studied into detail by resorting to a preliminary 3D simulation of the spray impingement realized in a proper experiment, where the engine injector is mounted at a certain distance from a cold or hot wall. An interesting comparison between numerical and experimental images of the in-cylinder spray dynamics is presented, that also allows individuating the difference in the wallfilm deposition under various injection strategies. This opens the way to understand the difference in the combustion development arising as injection is anticipated or retarded in the engine working cycle.

CFD and Optical Investigations of Fluid Dynamics and Mixture Formation in a DI-H2ICE

2010 ◽  
Author(s):  
Riccardo Scarcelli ◽  
Thomas Wallner ◽  
Hermann Obermair ◽  
Victor M. Salazar ◽  
Sebastian A. Kaiser
Keyword(s):  
Mole Fraction ◽  
Fuel Injection ◽  
Combustion Engine ◽  
Direct Injection ◽  
Three Dimensional ◽  
Symmetry Plane ◽  
Injection Velocity ◽  
Compression Stroke ◽  
Commercial Code ◽  
Wall Interaction

This paper reports the validation of a three-dimensional numerical simulation of the in-cylinder processes during gas-exchange, injection, and compression in a direct-injection, hydrogen-fueled internal combustion engine. Computational results from the commercial code Fluent are compared to experimental data acquired by laser-based measurements in a corresponding optically accessible engine. The simulation includes the intake-port geometry as well as the injection event with its supersonic hydrogen jet. The cylinder geometry is typical of passenger-car sized spark-ignited engines. Gaseous hydrogen is injected from a high-pressure injector with a single-hole nozzle. Numerically and experimentally determined flow fields in the vertical, central symmetry plane are compared for a series of crank angles during the compression stroke, with and without fuel injection. With hydrogen injection, the fuel mole-fraction in the same data plane is included in the comparison as well. The results show that the simulation predicts the flow field without injection reasonably well, with increasing numerical-experimental disagreement towards the end of the compression stroke. The injection event completely disrupts the intake-induced flow, and the simulation predicts the post-injection velocity fields much better than the flow without injection at the same crank-angles. The two-dimensional tumble ratio is evaluated to quantify the coherent barrel motion of the charge. Without fuel injection, the simulation significantly over-predicts tumble during most of the compression stroke, but with injection, the numerical and experimental tumble ratio track each other closely. The evolution of hydrogen mole-fraction during the compression stroke shows conflicting trends. Jet penetration and jet-wall interaction are well captured, while fuel dispersion appears under-predicted. Possible causes of this latter discrepancy are discussed.

Spray/wall interaction models for multidimensional engine simulation

2000 ◽  
Vol 1 (1) ◽  
pp. 127-146 ◽  
Author(s):  
Z Han ◽  
Z Xu ◽  
N Trigui
Keyword(s):  
Experimental Data ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Direct Injection ◽  
Jet Impingement ◽  
Spark Ignition ◽  
Linear Instability ◽  
Threshold Function ◽  
Wall Interaction ◽  
New Formulation

Models were developed to describe the spray wall impingement processes that take place in internal combustion engines. In this report focus is placed on the model formulation and experiment assessment of the spray/wall interaction submodels. It is identified that the Leidenfrost phenomenon is very unlikely to occur in a spark ignition (SI) engine including stratified-charge operation in a direct injection spark ignition (DISI) engine. A more comprehensive splashing/deposition threshold function is proposed to include the effects of surface roughness and pre-existing liquid film. Based on the wave phenomena observed on the surface of the liquid crown formed during drop impingement, a new splash breakup model is developed using linear instability analysis. The predicted drop size agrees well with available single-drop impingement experimental data. A new formulation for the post-impingement droplet velocity is also given which uses statistical sampling and jet impingement theory. The proposed models were assessed by comparing computations with two sets of experimental sprays impinging on a flat plate with the use of a pintle nozzle injector for port fuel injection (PFI) engines. The computed spray shape, normal and tangential penetration and droplet size show good agreement with experimental data.

Influence of Spray-Wall Interaction and Fuel Films on Cold Starting in Direct Injection Diesel Engines

1998 ◽  
Author(s):  
Donald W. Stanton ◽  
Andreas M. Lippert ◽  
Rolf D. Reitz ◽  
Christopher Rutland
Keyword(s):  
Diesel Engines ◽  
Direct Injection ◽  
Cold Starting ◽  
Wall Interaction

Validating the Phenomenological Smoke Model at Different Operating Conditions of DI Diesel Engines

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Y. V. Aghav ◽  
P. A. Lakshminarayanan ◽  
M. K. G. Babu ◽  
Azeem Uddin ◽  
A. D. Dani
Keyword(s):  
Diesel Engines ◽  
Direct Injection ◽  
Operating Conditions ◽  
Low Velocity ◽  
Engine Operation ◽  
Wide Range ◽  
Wall Impingement ◽  
Nozzle Hole ◽  
Wall Interaction ◽  
Geometrical Consideration

A new phenomenological model that was published in Aghav et al. (2005, “Phenomenology of Smoke From Direct Injection Diesel Engines,” Proceedings of ICEF2005, ASME Paper No. 1350) encompasses the spray and the wall interaction by a simple geometrical consideration. The current study extends this earlier work with investigations made on 16 different engines from six-engine families of widely varying features, applied to off-highway as well as on-road duty. A dimensionless factor was introduced to take care of the nozzle hole manufactured by hydroerosion, as well as the conical shape of the nozzle hole (k factor) in the case of valve-closed-orifice type of nozzles. The smoke emitted from the wall spray formed after wall impingement is the major contributor to the total smoke at higher loads. As the fuel spray impinges upon the walls of the combustion chamber, its velocity decreases. This low-velocity jet contributes to the higher rate of the smoke production. Therefore, the combustion bowl geometry along with injection parameters play a significant role in the smoke emissions. The new model is one dimensional and based on the recent phenomenological description of spray combustion in a direct injection diesel engine. The satisfactory comparison of the predicted and observed smoke over the wide range of engine operation demonstrated applicability of the model in simulation study of combustion occurring in direct injection (DI) diesel engines.

scholarly journals The effect of piston bowl temperature on diesel exhaust emissions

2005 ◽  
Vol 219 (3) ◽  
pp. 371-388 ◽  
Author(s):  
N Ladommatos ◽  
Z Xiao ◽  
H Zhao
Keyword(s):  
High Speed ◽  
Fuel Injection ◽  
Spray Deposition ◽  
Direct Injection ◽  
Exhaust Emissions ◽  
Oxides Of Nitrogen ◽  
Smoke Emission ◽  
Piston Bowl ◽  
Hydrocarbon Emission ◽  
Wall Interaction

In modern, high-speed, direct injection diesel engines for passenger vehicles, there is extensive impingement of the fuel sprays on to the piston bowl walls. Recent trends towards smaller engine sizes, equipped with high-pressure common-rail fuel injection systems, have tended to increase the spray/piston wall interaction. This paper describes tests carried out in a high-speed direct injection automotive diesel engine, during which the temperature of the piston was increased in a controlled manner between 189 and 227 °C while being continuously monitored. The aim of the work was to quantify the effects of piston temperature on pollutant exhaust emissions. The results show a significant reduction in unburned hydrocarbon emission, a significant increase in smoke emission, and no significant change in the emission of oxides of nitrogen. The increase in smoke emission cannot be ascribed to changes in the engine volumetric efficiency or air-fuel ratio. The paper demonstrates that fuel spray deposition on the piston surface was in the form of a thin film that did not experience bulk boiling. A number of suggestions are put forward to help explain the observed changes in exhaust emissions with increasing piston temperature.

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

1978 ◽  
Vol 36 (2) ◽  
pp. 650-651
Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo
Keyword(s):  
Direct Injection ◽  
Skin Pigmentation ◽  
Freeze Fracture ◽  
Pigment Granule ◽  
Time Lapse ◽  
Ultrastructural Level ◽  
Lanthanum Tracer ◽  
A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

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