Optimisation of In-Cylinder Flow for Fuel Stratification in a Three-Valve Twin-Spark-Plug SI Engine

Li, Yufeng; Zhao, Hua; Leach, Ben; Ma, Tom; Ladommatos, Nicos

doi:10.4271/2003-01-0635

Cited by 18 publications

(13 citation statements)

References 18 publications

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“…To reduce the loss of the actual highfrequency fluctuation in this procedure, a very small TSI jet atomizer was used to generate a fine mist of silicone oil droplets with a size of about 0.5-5 mm kernel size of 0.5 was used. It has been found in previous studies [14,19] used when compressed air at 3 bar was passed through a in the same measurement system [14,19] that serious bath of silicone oil. The particle mist was seeded into image distortion happened towards two sides of the the intake system.…”

Section: Piv Measurementmentioning

confidence: 89%

“…in SI engines using laser Doppler velocimetry (LDV) [8,[10][11][12], PTV [13] and particle image velocimetry 2.1 Optical engine and the PIV measurement plane (PIV) [12,[14][15][16][17][18][19] measurements and computational The engine used in the PIV experiment was a singlefluid dynamics (CFD) simulation [8,10,13]. Most cylinder Ricardo Hydra engine with an extended of these researches focus on the following basic piston and cylinder block.…”

Section: Methodsmentioning

confidence: 99%

“…The steady flow cylinder head respectively (Fig. 2) and two vertical planes parallel to each other and passing through the rig test results showed [19] that the modified cylinder head had a high tumble intensity factor of 2.6 and symmetric plane of the combustion chamber and the centre of one intake valve respectively (Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

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Characterization of an in-cylinder flow structure in a high-tumble spark ignition engine

Zhao

Leach

et al. 2004

International Journal of Engine Research

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A strong in-cylinder tumbling flow, which was produced by partially shrouding the lower periphery of the inlet valves, was measured in a three-valve twin-spark spark ignition (SI) engine using digital particle image velocimetry (PIV). Characteristics of the bulk flow, cyclic variation, frequency spectrum of velocity fluctuation, large- and small-scale fluctuation kinetic energy and integral length scale are analysed in detail. The possible effects of these flow characteristics on the charge stratification and subsequent ignition and combustion processes are also discussed. The results have shown that the strong tumble field was characterized by a very small velocity component in the direction of the tumble rotational axis until the late stage of the compression stroke. The cyclic variation of the bulk flow, though still present, was significantly reduced. Towards the end of the compression process, both low- and high-frequency velocity fluctuations were found to be high after the tumble had collapsed. The velocity fluctuation component along the cylinder axis was characterized by higher frequencies. An integral length scale was found in the range of 4–9 mm during the compression stroke.

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Section: Piv Measurementmentioning

confidence: 89%

Section: Methodsmentioning

confidence: 99%

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Characterization of an in-cylinder flow structure in a high-tumble spark ignition engine

Zhao

Leach

et al. 2004

International Journal of Engine Research

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“…The overall in-cylinder flow pattern is quantitatively studied using cross-tumble ratio (TRC), tumble ratio (TR) and swirl ratio (SR), which are generally expressed as follows 24,25 TRC=TR=SR =…”

Section: Analysis Of the Scavenging Process In The Two-stroke Poppet-mentioning

confidence: 99%

Influences of intake ports and pent-roof structures on the flow characteristics of a poppet-valved two-stroke gasoline engine

Zhao

2016

International Journal of Engine Research

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In order to minimize the short-circuiting of the intake charge in a poppet-valved two-stroke engine, a ''step structure'' on the intake side of the pent-roof was employed to shroud the bulk flow at the upper periphery of the intake valves at low valve lifts. Several intake-port geometries and pent-roof angles were evaluated on their charging and reversed tumble generating abilities using a steady flow test rig built in computational fluid dynamics, among which top-entry ports and relatively small pent-roof angle were selected. The scavenging processes of the two-stroke engine at high load and 3000 r/min condition with different intake valve seat heights were simulated and evaluated. The local flow patterns and composition distribution were also studied. The results show that lowering the intake valve seat height achieves higher delivery ratio and charging efficiency, but marginally better scavenging efficiency and slightly lower trapping efficiency. The scavenging process experiences a slow displacement period due to low flow momentum for the high valve seat cases and flow interaction at the exhaust exits for the low valve seat cases. Reversed tumble is the dominant flow pattern during the scavenging process. The lower the valve seat, the higher the tumble ratio in the early stage and at the end of the scavenging period. For all valve seat configurations, the least scavenged regions are located near the engine head wall and between the intake and the exhaust valves, while the regions rich in fresh charge are located along the major path of the reversed tumble. Low intake valve seat height is effective in increasing the overall in-cylinder air proportion. Further reducing it can result in higher fresh charge proportion below the exhaust valves and near the head wall.

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“…On the other hand, the microscopic methods can provide more details about the in-cylinder flow behavior. These methods include optical engines along with laser diagnostics such as laser Doppler anemometry (LDA) Shuliang et al (2000) and particle image velocimetry (PIV) Li et al (2003), Liu et al (2012), Begg et al (2009), Muller et al (2010, Wang et al (2011). Whilst, the other type of microscopic methods is the Computational Fluid Dynamics (CFD) simulation.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the In-Cylinder Tumble Motion inside GDI Cylinder at Different Planes under Steady-State Condition using Stereoscopic-PIV

El-Adawy

Heikal

Aziz

2019

JAFM

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This paper describes an experimental study aimed at the characterization of the steady-state tumble motion in the cylinder of an engine using stereoscopic particle image velocimetry (Stereo-PIV). More specifically, a pentroof four valves gasoline direct injection (GDI) engine head was mounted on a modified FEV steady-state flow rig for applying Stereo-PIV at different measurement vertical tumble planes at mid cylinder, mid injector and mid valve. The flow field was described by the distribution of the ensemble average flow patterns for 1000 pairs of images for every case, vorticity contours, turbulent kinetic energy and tumble ratio. The results revealed that the higher velocities acquired at the mid valve plane improved the turbulent kinetic energy and tumble ratio compared to the other planes. There was a good level of agreement between direct and indirect methods used for calculating the tumble ratio.

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Optimisation of In-Cylinder Flow for Fuel Stratification in a Three-Valve Twin-Spark-Plug SI Engine

Cited by 18 publications

References 18 publications

Characterization of an in-cylinder flow structure in a high-tumble spark ignition engine

Characterization of an in-cylinder flow structure in a high-tumble spark ignition engine

Influences of intake ports and pent-roof structures on the flow characteristics of a poppet-valved two-stroke gasoline engine

Experimental Investigation of the In-Cylinder Tumble Motion inside GDI Cylinder at Different Planes under Steady-State Condition using Stereoscopic-PIV

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