Characteristics of in-cylinder flow and mixture formation in a high-pressure spray-guided gasoline direct-injection optically accessible engine using PIV measurements and CFD

Kim, Dong Hwan; Shin, Jisoo; Son, Yousang; Park, Sungwook

doi:10.1016/j.enconman.2021.114819

Cited by 30 publications

(11 citation statements)

References 39 publications

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“…At an injection timing of BTDC 180°, the spray direction was more towards the cylinder liner as illustrated in Fig. 7 c. This was due to the upward in-cylinder flow at this injection timing 34 , which led unevaporated fuel droplets contact and stick on the cylinder liner creating wall film. As a result, the wall film at the cylinder liner was met with the combustion flame front, causing diffusion flame.…”

Section: Resultsmentioning

confidence: 91%

Effects of lubricant-fuel mixing on particle emissions in a single cylinder direct injection spark ignition engine

Seo

et al. 2022

Sci Rep

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Gasoline direct injection (GDI) engines emit less carbon dioxide (CO2) than port fuel injection (PFI) engines when fossil fuel conditions are the same. However, GDI engines emit more ultrafine particulate matter, which can have negative health effects, leading to particulate emission regulations. To satisfy these regulations, various studies have been done to reduce particulate matter, and several studies focused on lubricants. This study focuses on the influence of lubricant on the formation of particulate matter and its effect on particulate emissions in GDI engines. An instrumented, combustion and optical singe-cylinder GDI engine fueled by four different lubricant-gasoline blends was used with various injection conditions. Combustion experiments were used to determine combustion characteristics, and gaseous emissions indicated that the lubricant did not influence mixture homogeneity but had an impact on unburned fuels. Optical experiments showed that the lubricant did not influence spray but did influence wall film formation during the injection period, which is a major factor affecting particulate matter generation. Particulate emissions indicated that lubricant included in the wall film significantly affected PN emissions depending on injection conditions. Additionally, the wall film influenced by the lubricant affected the overall particle size and its distribution.

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Section: Resultsmentioning

confidence: 91%

Effects of lubricant-fuel mixing on particle emissions in a single cylinder direct injection spark ignition engine

Seo

et al. 2022

Sci Rep

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“…30 The tumble ratio was the ratio of the angular velocity of the tumble center to the angular velocity of the engine. These were calculated by the following equation 20,31 :…”

Section: Methodsmentioning

confidence: 99%

“…The simulation model was validated in a previous study on the aspects of in-cylinder flow and spray development. 31,37 The further validation results for various piston crown designs are presented in Figure 7. The velocity distribution of the simulation results had a higher level of velocity compared to the PIV experiment results (Figure 9).…”

Section: Computational Methodologymentioning

confidence: 99%

Effects of piston crown designs on in-cylinder flow and mixture formation in gasoline direct injection engine under the lean burn condition

Kim

Shin

Kim

et al. 2023

International Journal of Engine Research

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In this study, the effects of piston shapes on in-cylinder flow characteristics and mixture formation in the lean condition was analyzed using the PIV method and CFD (CONVERGE v2.4). The four-piston geometries were concave, flat, convex, and base pistons, and the pistons were mounted on a GDI engine with transparent quartz. To quantify in-cylinder flow characteristics, the mean velocity, tumble ratio, turbulent kinetic energy, and tumble center were calculated. In addition, to analyze the effects of the difference in piston shapes in detail, the velocity fraction was calculated by dividing the cylinder area into three. In-cylinder flow was compared for the case without injection and the case with injection. There were four timed injections at C.A. 420°, 480°, 540°, and 600°, and the mixture characteristics were investigated in the cases of 480° and 600° injection. In the intake process and early compression process, there was no significant difference in the quantitative values for the shape of the piston regardless of the presence or absence of injection. However, the effects of the piston crown designs increased in the later compression process. As a result, the highest turbulent kinetic energy was found using a flat piston with a relatively high tumble ratio and swirl ratio in the absence of injection. The mixture formation was similar for all piston crown designs when injected at the crank angle of 480°. However, when the crank angle of 600° was injected, a stagnant fuel area was formed using the base-type piston, so it was difficult to secure sufficient fuel near the center of the cylinder.

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“…Spray, as a medium consisting of a liquid phase dispersed in a gaseous environment, is a natural candidate for PIV diagnostics. It has been used to verify the function of new types of atomiser [13], or to monitor and describe the liquid breakup for different types of atomisers [14,15]. This method can be used to track the motion of liquid particles in sprays [16] as the well as velocity fields in the surrounding gas [18].…”

Section: Introductionmentioning

confidence: 99%

Multi-Exposure PIV Measurements of Velocity Fields in Sprays

2022

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This paper presents an approach to the use of the PIV method in the diagnosis of sprays generated by an effervescent atomiser. Due to the different density of the liquid phase depending on the distance from the nozzle, problems arise with the correct exposure of images for PIV analysis. The aim of the authors of this paper is to outline the possibility of solving this problem by composing a velocity field from partial measurements. To meet the objectives of the paper, in-house PIV equipment (hardware and software) was used rather than a commercial setup. This allowed for easier handling of the measured data and more sophisticated post-processing than offered by commercial products. It is clear from the results presented that, despite the fundamental differences in the optical properties of the spray particles, it is possible to obtain a velocity field from the discharge zone to the spray region with fine droplets. Moreover, it is possible to combine velocity measurements in the spray cone with measurements in the surrounding environment. Research background: Spray is an environment with an abundance of tracers for PIV analysis (droplets), but their density, size and shape vary dramatically with distance from the nozzle. The use of PIV can therefore be challenging due to the demands of this method for correct image exposure. Purpose of the article: Introduction of the application of the PIV method for environments with variable density and size of tracer particles Methods: PIV, image processing. Findings & Value added: By taking an appropriate approach to acquiring the source PIV images, it is possible to obtain information about the velocities throughout the spray cone as well as in the surrounding environment. The application of the proposed method requires a sufficiently large source data set (images) and sophisticated postprocessing. However, as a result, it is possible to obtain an overall view of the velocity field in the spray cone starting from the area behind the nozzle to the fine droplet region.

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Characteristics of in-cylinder flow and mixture formation in a high-pressure spray-guided gasoline direct-injection optically accessible engine using PIV measurements and CFD

Cited by 30 publications

References 39 publications

Effects of lubricant-fuel mixing on particle emissions in a single cylinder direct injection spark ignition engine

Effects of lubricant-fuel mixing on particle emissions in a single cylinder direct injection spark ignition engine

Effects of piston crown designs on in-cylinder flow and mixture formation in gasoline direct injection engine under the lean burn condition

Multi-Exposure PIV Measurements of Velocity Fields in Sprays

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