Numerical Prediction of Stratified Charge Distribution in a Gasoline Direct-Injection Engine - Parametric Studies

Joh, Miok; Huh, Kang Y.; Noh, Seok Hong; Choi, Kyu Hoon

doi:10.4271/1999-01-0178

Cited by 18 publications

(3 citation statements)

References 27 publications

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“…In this study, the stratified flame ignition (SFI) hybrid combustion was proposed to generate a stable flame kernel and hence control the heat release process of SI-CAI hybrid combustion by dual-injection strategy at stratified charge operations. The stratified flame kernel is formed around the spark plug by fuel stratification in the same way as a stratified charge DI gasoline engine through the appropriate direct injection strategy in combination with a suitable bowl piston [29][30][31][32][33]. The piston shape should be well designed to induce the direct injected fuel to the vicinity of spark plug.…”

Section: Introductionmentioning

confidence: 99%

Effect of piston shapes and fuel injection strategies on stoichiometric stratified flame ignition (SFI) hybrid combustion in a PFI/DI gasoline engine by numerical simulations

Wang

Zhao

Xie

2015

Energy Conversion and Management

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a b s t r a c tIn this research, the stratified flame ignition (SFI) hybrid combustion process was proposed to enhance the control of SI-CAI hybrid combustion and moderate the maximum pressure rise rate (PRR max ) by the combination of port fuel injection (PFI) and direct injection (DI). The effect of the stratified flame formed by different piston shapes, start of direct injection (SOI) timings and direct injection ratios (r DI ) on the stoichiometric SFI hybrid combustion and heat release process was studied using the three-dimensional computational fluid dynamics (3-D CFD) simulations. The spark ignited flame propagation near the spark plug and the auto-ignition heat release process of the diluted mixture were modelled in the framework of 3-Zones Extended Coherent Flame Model (ECFM3Z) by the extended coherent flame model and tabulated auto-ignition chemistry of a 4-component gasoline surrogate, respectively. The operating load of indicated mean effective pressure (IMEP) 3.6 bar was selected to represent a typical part-load operation. The sweep of the spark timing (ST) was performed for different pistons, SOI timings and direct injection ratios. The SFI hybrid combustion process with the same combustion phasing was investigated in details. The optimal stratified mixture pattern, characterized with the central rich mixture around spark plug and stratified lean mixture at the peripheral region, formed by the newly designed Piston A and B effectively lowers the PRR max with a slight deterioration of IMEP. The later SOI timing advances the crank angle of 50% total heat release (CA50) and significantly reduces the PRR max with a little deterioration of IMEP. As the direct injection ratio is increased, both the PRR max and IMEP decrease. During the SFI hybrid heat release process, spark timing is effective to control CA50, IMEP and PRR max regardless the piston shapes, SOI timings and direct injection ratios. However, the sensitivity of SFI hybrid combustion to the stratified mixture varies with the spark timing. The reduction of the PRR max caused by the stratified flame enables the advance of spark timing to achieve maximum IMEP.

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Section: Introductionmentioning

confidence: 99%

Effect of piston shapes and fuel injection strategies on stoichiometric stratified flame ignition (SFI) hybrid combustion in a PFI/DI gasoline engine by numerical simulations

Wang

Zhao

Xie

2015

Energy Conversion and Management

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“…Xu et al [21] applied CFD modeling method to optimize piston shapes to form the rich fuel cloud around the spark plug in a GDI engine. The numerical simulations performed by Joh et al [22] also demonstrated that piston shape had a strong influence on air-fuel interaction and the charge distribution around spark plug. The invention reported in [23] designed a combustion chamber including a bowl piston for a gasoline direct-injection controlled autoignition combustion engine.…”

Section: Hui Xie and Bang-quan Hementioning

confidence: 92%

Numerical Study of the Effect of Piston Shapes and Fuel Injection Strategies on In-Cylinder Conditions in a PFI/GDI Gasoline Engine

Wang¹,

Zhao²,

Xie³

et al. 2014

SAE Int. J. Engines

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INTRODUCTIONControlled Auto-ignition (CAI) combustion has been shown to effectively reduce the NOx emissions and increase fuel efficiency [1] and it has been subject to extensive studies in the past few decades. However, the lack of direct control on the auto-ignition process and relatively narrow operation range inhibit the practical application of this low temperature high efficient combustion mode [2]. In order to enhance the control of auto-ignition and extend the operation range of CAI combustion, spark ignition (SI) was used to assist CAI combustion. In this case, the early flame propagation induced by spark discharge could effectively control the later autoignition [3,4]. In addition, this hybrid combustion mode could be used to bridge pure SI mode and CAI mode during mode transition when applying to the full load operations in the practical engine [2,5,6,7,8]. However, the recent study on the SI-CAI hybrid combustion indicated the existence of significant cycle-to-cycle variation (CCV) during mode transition [8, 9, 10, 11].In the SI-CAI hybrid combustion, the flame propagation is mainly controlled by the transport of heat and active species in the flame front and distorted by the in-cylinder turbulence [12]. The variation of the early flame propagation would in turn affect the later auto-ignition process [13]. The premise of controlling and stabling SI-CAI hybrid combustion is to effectively manage the early flame propagation process. The local fuel/air equivalence ratio around the spark plug significantly affects the spark kernel formation and flame propagation process in spark ignition engine. Persson et al. [14] used high speed fuel Planar Laser-Induced Fluorescence (PLIF) to study the effect of fuel stratification on spark assisted compression ignition (SACI) with ethanol as fuel. They found the lower fuel concentration in the vicinity of the spark plug decreased the flame expansion speed with the overall lean mixture (lambda 1.4). Middleton et al. [15] investigated the propagation of premixed laminar reaction fronts with different fuel/air equivalence ratios using transient one-dimensional flame simulations and indicated the increased flame burning velocity with the isooctane/air equivalence ratio increasing from 0.1 to 1.0. The experimental Numerical Study of the Effect of Piston Shapes and Fuel Injection Strategies on In-Cylinder Conditions in a PFI/GDI Gasoline EngineXinyan Wang and Hua Zhao Tianjin Univ., Brunel Univ.Hui Xie and Bang-Quan He Tianjin Univ.ABSTRACT SI-CAI hybrid combustion, also known as spark-assisted compression ignition (SACI), is a promising concept to extend the operating range of CAI (Controlled Auto-Ignition) and achieve the smooth transition between spark ignition (SI) and CAI in the gasoline engine. In order to stabilize the hybrid combustion process, the port fuel injection (PFI) combined with gasoline direct injection (GDI) strategy is proposed in this study to form the in-cylinder fuel stratification to enhance the early flame propagation process and control the auto-...

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“…They also found that in-cylinder fluid motion was affected by the fuel injection. Milok et al [25], performed numerical analysis on four-stroke four-valve GDI (gasoline direct injection) engine using two piston shapes at two engine speeds. They observed that piston shape had a strong influence on air-fuel interaction at the later stage of fuel injection and lower engine speed was better for getting a stratified mixture as sufficient time was available for evaporation of fuel.…”

Section: Introductionmentioning

confidence: 99%

Effect of piston shape on in-cylinder flows and air–fuel interaction in a direct injection spark ignition engine – A CFD analysis

Harshavardhan

Mallikarjuna

2015

Energy

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Numerical Prediction of Stratified Charge Distribution in a Gasoline Direct-Injection Engine - Parametric Studies

Cited by 18 publications

References 27 publications

Effect of piston shapes and fuel injection strategies on stoichiometric stratified flame ignition (SFI) hybrid combustion in a PFI/DI gasoline engine by numerical simulations

Effect of piston shapes and fuel injection strategies on stoichiometric stratified flame ignition (SFI) hybrid combustion in a PFI/DI gasoline engine by numerical simulations

Numerical Study of the Effect of Piston Shapes and Fuel Injection Strategies on In-Cylinder Conditions in a PFI/GDI Gasoline Engine

Effect of piston shape on in-cylinder flows and air–fuel interaction in a direct injection spark ignition engine – A CFD analysis

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