Measurement and Modeling on Wall Wetted Fuel Film Profile and Mixture Preparation in Intake Port of SI Engine

Senda, Jiro; Ohnishi, Masanori; Takahashi, Tomohiro; Fujimoto, Hajime; Utsunomiya, Atsushi; Wakatabe, Michio

doi:10.4271/1999-01-0798

Cited by 59 publications

(36 citation statements)

References 27 publications

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“…A sensitivity analysis to the threshold has been performed in the previous study [20] to obtain the accurate spray boundary. Unnecessary shapes obtained in the binary image are filtered using morphological tools.…”

Section: Image Processingmentioning

confidence: 99%

“…Film formation is one of the important properties as a result of spray-wall impingement. Senda et al [20] applied laser-induced fluorescence (LIF) to quantitatively measure the adhered fuel film on a flat glass under atmospheric pressure and room temperature. The adhered fuel measured by LIF showed almost 40% of the total injection quantity at 10 ms after the end of injection while the adhered fuel is relatively insensitive to injection duration.…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Study of Diesel Spray Impingement on a Flat Plate: Effects of Injection Conditions

Zhu

Zhao

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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Advanced injection strategies for internal combustion engines have been extensively studied although there still exists a significant fundamental knowledge gap on the mechanism for high-pressure spray interaction with the piston surface and chamber wall in the internal combustion engine. The current study focuses on providing qualitative and quantitative information on spray-wall impingement and its characteristics by expanding the range of operating parameters under engine-like conditions. Parameters considered in the experiment are ambient gas and fuel injection conditions. The test included the non-vaporizing spray at the different ambient density (14.8, 22.8 and 30 kg/m 3 ) and injection pressure (1200, 1500 and 1800 bar) with the isothermal condition (ambient, and plate temperatures of 423 K). The test was conducted in the constant-volume vessel with the 60-degree impinging spray angle relative to the plate. The free spray and impinged spray properties were qualitatively analysed based on Mie and schlieren images. The results showed that the lower ambient density and higher injection pressure tended to result in relatively higher impinged spray height. The expanding shape of the impinged spray on the wall showed the oval shape.Keywords free spray; impinged spray; wall-impinged expanding spray; flat plate Introduction Internal combustion engines (ICEs) have been the dominant power supply for automobiles since the 20 th century and will keep playing an important role in transportation sectors in the coming decades. Increasingly stringent fuel consumption and emission standards are driving automotive research. Advanced injection strategies such as increasing injection pressure, multiple injections, injection timing control, and many others can enhance fuel efficiency in the application of direct injection spark ignition (DISI) engines and direct injection (DI) diesel engines. The DISI and DI diesel engines are able to achieve such higher efficiencies by means of better spray atomization and air-fuel mixing. Besides injection parameters mentioned above, the spray-wall interaction plays a critical role in fuel spray dispersion and subsequent combustion event [1][2][3]. The fuels used in ICEs undergo the vaporization process and mix with air before combustion. However, the fuel spray may impinge on the engine surfaces before it is fully vaporized [4]. The non-vaporizing spray possibly impinges on the cylinder head or liner in DI engines and even on the inlet valves in port fuel injected (PFI) engines. The spray-wall impingement usually forms a liquid film on the wall, which is referred to wall-wetting phenomenon [5]. The fuel deposition on the wall may survive during the combustion phase, resulting in producing unburned hydrocarbon (HC) and particulate matter (PM) emissions [6][7][8]. Especially in cold operation (such as cold start and warm-up), the wall wetting in PFI engines becomes dominant mechanism for engine-out HC emissions [9][10][11][12][13]. When the spray droplets hit the wall, they may und...

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Section: Image Processingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Experimental Study of Diesel Spray Impingement on a Flat Plate: Effects of Injection Conditions

Zhu

Zhao

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

View full text Add to dashboard Cite

show abstract

“…They claimed that the sensitivity of the technique was in the order of 1µm, and the accuracy was estimated to be 10%. Senda et al (1999) measured the 2-D distribution of the fuel film thickness formed on a flat plate by using the LIF technique at an atmospheric pressure and room temperature condition. The fuel was isooctane mixed with biacetyl (6% by volume) as a dopant.…”

Section: -4-1 Laser-induced Fluorescence (Lif) Techniquementioning

confidence: 99%

Fuel Film Temperature and Thickness Measurements on the Piston Crown of a Direct-Injection Spark-Ignition Engine

Park¹,

Ghandhi²

2005

SAE Technical Paper Series

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The fuel film thickness and temperature on the piston crown of a direct-injection spark-ignition (DISI) engine were measured using a fiber-based laser induced fluorescence (LIF) method. The engine investigated employed a wall-guided swirl-type system using a high-pressure swirl injector impinging onto the piston crown. The fuel used was isooctane with a small amount of a fluorescent liquid dopant. The measured fluorescence intensity was transformed to the fuel film thickness by way of the equations based on photophysics and the fiber optic properties. However, the fluorescence of the fuel mixture showed a strong dependency on the fuel temperature and this information was needed in the fuel film thickness calculation. The fuel film temperature, which may differ from the piston surface temperature, was measured by using a fiber-based fluorescence thermometry method.Engine tests were performed for motored and fired conditions under the late injection stratified mode. The results of the fuel film temperature measurement showed that the mean fuel film temperature follows the piston surface temperature and the convection heat transfer from the compressed hot air directly affected the mean fuel film temperature during the compression and expansion stroke. The fuel film thickness measurement results showed that the boiling point of the liquid dopant should be much higher than that of the main fuel to ii meet the co-evaporation condition. The fuel film persisted during the expansion stroke and started to evaporate actively from the exhaust valve opening crank angle for both motored and fired conditions. The fuel film thickness from the fuel injection to just before the occurrence of pool fires was the same level for motored and fired engine conditions although the piston temperature was higher for the fired condition. The spark ignition and the main flame before the pool fires do not affect the fuel film thickness. The duration and thickness of the fuel film was strongly affected by the boiling point of the fuel. The fuel film evaporates quicker for a fuel having a lower boiling point.

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“…High injection pressures increase the collision velocity, which makes the droplets smaller and improves atomization after the impact [13]. The experimental analysis of surface jet impact has been accompanied in recent years, by the development of models oriented to study both the macroscopic behavior of the jet-wall impact and the simulation of the microscopic interaction of isolated droplets [10], [12], [14]. However, there is a large number of processes that are not sufficiently known to achieve certain accurate numerical predictions, such as evaporation of the fuel film [14].…”

Section: Introductionmentioning

confidence: 99%

“…The distance from the tip of the nozzle to the surface affects the spray-wall interaction [10], since the impact conditions depend on the spray momentum and the energy exchange between the jet and the surrounding air until it hits the wall. Also, the orientation of the jet, or angle of incidence with respect to the wall also modifies the interaction mechanisms, as it changes the balance of forces during impact [11], [12]. High injection pressures increase the collision velocity, which makes the droplets smaller and improves atomization after the impact [13].…”

Section: Introductionmentioning

confidence: 99%

Spray/wall interaction analysis on an ECN single-hole injector at diesel-like conditions through Schlieren visualization.

Payri

Peraza

Bazyn

2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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To continuously improve CFD models which simulate spray evolution, breakup and evaporation mechanisms, it is helpful to validate them with results obtained by experimental research. In the present study, a mono-orifice target nozzle from Engine Combustion Network, referred to as Spray D, was investigated at conditions of spray-wall interaction, which actually is a real situation in internal combustion engines that is not frequently analyzed by visualization. A Photron SA-X2 high-speed camera was employed to record the vapor phase development of the spray in an inert atmosphere using a Schlieren imaging single-pass setup. The experiments show that the spreading of the spray along the wall has a behavior fairly similar to penetration at free-jet situations, especially regarding to its susceptibility to the operating conditions and its proportionality to the square root of time once the spray reaches a steady regime interacting with the wall. Furthermore, the spray film thickness was measured at three distances from the spray-wall impact point during the injection event, thereby characterizing that parameter both spatially and temporally. The tests were carried out in a constant pressure-flow facility able to reproduce pressure and temperature conditions, similar to those seen into a diesel engine. In order to observe the behavior of the spray colliding with a wall within this test rig, a system capable to being fitted into it and to holding a fused quartz wall at different injector tip-wall distances and impingement angle configurations, was designed and employed. IntroductionAt present, the study of the spray-wall interactions into the field of transportation systems is increasingly relevant in a world aimed at reducing the displacement per cylinder of the internal combustion engines. This phenomenon plays a fundamental role in the mixing and evaporation of fuel , the impact of spray with a wall is a subject of difficult analysis both theoretically and experimentally due to the highly transient nature of the spray and the high spatio-temporal variability of the event. Because of this, its effects on the engine performance are not entirely known. On the one hand, the incidence and accumulation of fuel in the cylinder walls can lead to the formation of a fuel film that worsens combustion, promotes the emission of carbon monoxide and unburned hydrocarbons and involves energy losses given the increase of heat transfer [7]. On the other hand, the impact of the spray with a surface tends to improve the mixing of the fuel in the air due to both the impact and the subsequent expansion of the front of the jet. The complexity of the jet-wall impact phenomenon has to be added to the overall complexity of the injection-combustion processes, which, although they have been extensively studied in 'free jet' conditions [7]-[9] remain an active area of research.

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Measurement and Modeling on Wall Wetted Fuel Film Profile and Mixture Preparation in Intake Port of SI Engine

Cited by 59 publications

References 27 publications

An Experimental Study of Diesel Spray Impingement on a Flat Plate: Effects of Injection Conditions

An Experimental Study of Diesel Spray Impingement on a Flat Plate: Effects of Injection Conditions

Fuel Film Temperature and Thickness Measurements on the Piston Crown of a Direct-Injection Spark-Ignition Engine

Spray/wall interaction analysis on an ECN single-hole injector at diesel-like conditions through Schlieren visualization.

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