Effect of Combustion Chamber Shape on In-Cylinder Flow and Air-Fuel Interaction in a Direct Injection Spark Ignition Engine - A CFD Analysis

Harshavardhan, Ballapu; Mallikarjuna, J M

doi:10.4271/2015-26-0179

Cited by 7 publications

(7 citation statements)

References 14 publications

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“…The atomization quality criterion used for the analysis of the results was, as previously mentioned, determined in experiments: the percentage distribution of the spray diameter ranges; the Sauter mean diameter, D [3,2] ; the spread of the droplet distribution calculated on the basis of the percentile diameters D v (10), D v (50), and D v (90); and the percentage of droplets with diameters falling within the diameter ranges (i.e., diameter classes) D [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] , D , D , and D [100-1000] (the numbers in indexes are diameter ranges in micrometers for a given diameter class). The classes were selected considering the ranges relevant to the course of the combustion process; typically, these are analyzed in the scientific literature.…”

Section: Methodsmentioning

confidence: 99%

“…A comparison of the time distributions of the fuel droplet diameters belonging to the assumed diameter classes D [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] , D , D Droplets with diameters greater than 40 µm are acceptable under certain combustion conditions. The presence of drops with diameters greater than 100 µm is the main cause of incomplete combustion and pollution of exhaust gases.…”

Section: Temporal Percentage Distribution Of Aerosol Fuel Droplet Dia...mentioning

confidence: 99%

“…This possibly applies to the homogeneous atomization of the fuel in the entire volume of the combustion chamber, proper fragmentation of the fuel dose fed into the cylinder, and even mixing of fuel and air in the entire combustible mixture. The listed characteristics of the combustible mixture are usually obtained by appropriately shaping the air intake duct (the spiral-shaped inlet and swirling blades) [1,2], the combustion chamber [3] (the shape of the piston crown and the shape of the surface of the cylinder head closing the combustion chamber) [4,5], the proper atomization of the fuel by the injector [6,7], additional devices and ignition delay [8], and fuel injection strategy [9].…”

Section: Introduction 1modification Of the Characteristics Of A Combu...mentioning

confidence: 99%

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The Effect of Internal Combustion Engine Nozzle Needle Profile on Fuel Atomization Quality

Klyus,

Szczepanek,

Kidacki

et al. 2024

Energies

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This article presents the results of research on the impact of changing the cross-section of an atomizer’s flow channel, which is caused by changing the flow geometry of the passive part of the needle on the drop diameter distribution of the fuel spray. A three-hole type H1LMK, 148/1 atomizer with hole diameters, dN, equal to 0.34 mm, is analyzed. A nozzle with a standard (i.e., unmodified) needle and three nozzles using needles with a modified profile in the flow part of the needle, marked by the code signatures 1L, 2L, and 3L, are tested. An increasing level of fuel turbulence characterizes the needles during the flow along their flow part due to the use of one (1L), two (2L), and three (3L) de Laval toroidal nozzles, respectively, obtained by mechanically shaping the outer surface of the flow part of the spray needle. The spray produced is tested using the Malvern Spraytec STP 500 device cooperating with the dedicated Malvern version 4.0. During the tests, measurements and an analysis of the spray droplet size distribution over the entire injection duration, equal to 7 ± 2 ms, are made for each nozzle. The experiment makes it possible to determine the effect of the nozzle needles’ profiles on the time distribution of the actual droplet diameters; the time distribution of the Sauter mean droplet diameters, D[3,2]; the percentile shares of the droplet diameters Dv (10), Dv (50), and Dv (90); the distribution span during the development of the spray stream; and the time distribution of the shares of the droplets with diameters belonging to selected diameter classes D[x1−x2] in the spray. The results of the measurements of the drop diameter distribution indicate that using atomizers with a modification to the flow channel allows for an increase in the share of droplets with smaller diameters compared to the standard atomizer.

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Section: Methodsmentioning

confidence: 99%

Section: Temporal Percentage Distribution Of Aerosol Fuel Droplet Dia...mentioning

confidence: 99%

Section: Introduction 1modification Of the Characteristics Of A Combu...mentioning

confidence: 99%

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The Effect of Internal Combustion Engine Nozzle Needle Profile on Fuel Atomization Quality

Klyus,

Szczepanek,

Kidacki

et al. 2024

Energies

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“…The results indicated that turbulent kinetic energy, length scale as well as swirl and tumble ratios in case of flat piston were higher than that of other cases [10]. On the other hand, on the same research conditions, the results of B. Harshavardhan claimed that the flat piston was more proper for spark ignition engine and the air -fuel mixture was more flammable [11]. Pargaonkar et el.…”

Section: Introductionmentioning

confidence: 90%

Untitled

2023

JST: ETSD

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Gas flow behaviour is an extremely complicated question on internal combustion engine and plays a key role in air-fuel mixing performance. A proper mixture process significantly improves the combustion performance and thus enhances the engine efficiency. This study estimates the effect of different piston bowl depths on the flow field development inside the combustion chamber of a CNG engine using Ansys Fluent. The cold flow model was utilized without considering the combustion behaviour. The three-dimensional model was developed based on a single cylinder CNG converted engine. Four different bowl heights were applied while the compression ratio was maintained as the designed value of 10. The tumble and swirl as well as the turbulent flow pattern were investigated to consider the gas flow behaviour. The simulation results indicate that the tumble and swirl ratio increase with increasing of piston bowl depth. The case of bowl height 17 mm shows better flow behaviour and higher velocity for a good mixing performance as well as turbulence dissipation.

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“…On the other hand, the spray formation is largely guided by the shape of the piston top surface. Numerical simulations and research experiments have been applied to probe into the effects of the piston top contour on the flow structure and combustion features of GDI engines (Harshavardhan & Mallikarjuna, 2015a;Raj et al, 2013). Faure et al (1998) carried out research on the in-cylinder tumbling flow structure in a motored GDI engine using the techniques of particle image velocimetry (PIV) and laser Doppler anemometry (LDA).…”

Section: Introductionmentioning

confidence: 99%

Effect of the piston top contour on the tumble flow and combustion features of a GDI engine with a CMCV: a CFD study

Yin

Zhang

Sun

et al. 2016

Engineering Applications of Computational Fluid Mechanics

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In spite of much progress in the development of gasoline direct injection (GDI) engines, choosing an appropriate piston top contour to obtain desirable combustion efficiency is still an arduous process for engineers. This study investigates the combined effects of piston bowl geometry and a charge motion control valve (CMCV) on tumble flow and combustion features in GDI engines. Based on the model validation, the processes of intake, spray, mixture formation and combustion at different engine speeds are simulated and analyzed for different piston shapes for the two cases of opening and closing the CMCV. The results show that the bowl on the top of piston is beneficial for the formation and development of tumble flow. The flat top piston with the CMCV closed is able to achieve acceptable combustion pressure. However, with the increase of engine speed and load, the advantages of the flat top pistons gradually disappear; the dual offset bowl piston has a minimum tumble ratio and turbulence kinetic energy (TKE) at the end of the compression stroke because of the projection in the middle of the piston top surface which leads to a lower pressure rise rate and a reduced flame propagation speed at high load. The closed CMCV contributes to a faster evaporation rate and a more uniform mixture at lower speeds. It is not recommended for use at high speeds due to lower intake air mass and reduced combustion pressure. The research provides an effective way for engineers to choose an appropriate piston top contour combined with a CMCV to obtain desirable combustion efficiency. ARTICLE HISTORY

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Effect of Combustion Chamber Shape on In-Cylinder Flow and Air-Fuel Interaction in a Direct Injection Spark Ignition Engine - A CFD Analysis

Cited by 7 publications

References 14 publications

The Effect of Internal Combustion Engine Nozzle Needle Profile on Fuel Atomization Quality

The Effect of Internal Combustion Engine Nozzle Needle Profile on Fuel Atomization Quality

Untitled

Effect of the piston top contour on the tumble flow and combustion features of a GDI engine with a CMCV: a CFD study

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