Effects of Injector Parameters on Mixture Formation for Multi-Hole Nozzles in A Spray-Guided Gasoline DI Engine

Skogsberg, Mikael; Dahlander, Petter; Lindgren, Ronny; Denbratt, Ingemar

doi:10.4271/2005-01-0097

Cited by 43 publications

(17 citation statements)

References 4 publications

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“…These show typical characteristics of high-pressure spray dynamics, with plumes 1 and 6 exhibiting the so-called 'fishbone' structure as a result of distribution of the smaller slow-moving droplets to the outside of the plume; this results from airentrainment caused by high shear forces at the air-spray interface which set up recirculation zones that become wider with increasing distance from the nozzle. Similar observations have been also reported in other recent publications [9][10][11]. The spray development in Figure 8 was captured for an injection timing of 80° CA ATDC with the engine now motoring at 1500 RPM under part load (0.5 bar intake pressure) and demonstrates the effect of the intake flow through the valves.…”

Section: Spray Formation and Flow Effectssupporting

confidence: 70%

Spray Development, Flow Interactions and Wall Impingement in a Direct-Injection Spark-Ignition Engine

Serras-Pereira¹,

Aleiferis²,

Richardson³

et al. 2007

SAE Technical Paper Series

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Levels of liquid fuel impingement on in-cylinder surfaces in direct injection spark ignition engines have typically been higher than those in port-fuel injection engines due to in-cylinder injection and higher injection pressures. The result is typically an increase in the levels of un-burned hydrocarbons and smoke emissions which reduce the potential fuel economy benefits associated with direct injection engines. Although different injection strategies can be used to reduce these effects to some extent, full optimisation of the injection system and combustion process is only possible through improved understanding of spray development that can be obtained from optical engine investigations under realistic operating conditions. To this extent, the spray formation from a centrally mounted multihole injector was studied in a single-cylinder optical directinjection spark-ignition engine under part-load conditions (0.5 bar intake plenum pressure) at 1500 RPM. A highspeed camera and laser illumination were used to obtain Mie-scattering images of the spray development on different in-cylinder planes for a series of consecutive engine cycles. The engine temperature was varied to reflect cold-start (20 °C) and fully warm (90 °C) engine conditions. A multicomponent fuel (commercial gasoline) and a singlecomponent fuel (iso-octane) were both tested and compared to investigate the effects of fuel properties on spray formation and wall impingement. An experimental arrangement was also developed to detect in-cylinder liquid fuel impingement using heat flux sensors installed on the cylinder liner. Two different injection strategies were tested; a typical single-injection strategy in the intake stroke to promote homogeneous mixture formation, as well as a triple-injection strategy around the same timing to assess the viability of using multiple-injection strategies to reduce wall impingement and improve mixture preparation. A sweep of different locations around the cylinder bore revealed the locations of highest fuel impingement levels which did not correspond directly to the nominal spray plume trajectories as a result of spray-flow interactions. These results were analysed in conjunction with the observed effects from the parallel imaging investigation.

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Section: Spray Formation and Flow Effectssupporting

confidence: 70%

Spray Development, Flow Interactions and Wall Impingement in a Direct-Injection Spark-Ignition Engine

Serras-Pereira¹,

Aleiferis²,

Richardson³

et al. 2007

SAE Technical Paper Series

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show abstract

“…The different levels of drag and rates of transport of droplets away from the leading edge are both dictated by local conditions and fluid properties and, are thus believed to be the main mechanisms governing the observed differences in spray development for each of the tested fuels. Similar mechanisms for spray breakup from multi-hole atomizers using standard fuels such as gasoline have been reported in [19][20][21].…”

Section: ° Mirrormentioning

confidence: 83%

Characteristics of Ethanol, Butanol, Iso-Octane and Gasoline Sprays and Combustion from a Multi-Hole Injector in a DISI Engine

Serras-Pereira

Aleiferis

Richardson³

et al. 2008

SAE Int. J. Fuels Lubr.

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Recent pressures on vehicle manufacturers to reduce their average fleet levels of CO 2 emissions have resulted in an increased drive to improve fuel economy and enable use of fuels developed from renewable sources that can achieve a net reduction in the CO 2 output of each vehicle. The most popular choice for spark-ignition engines has been the blending of ethanol with gasoline, where the ethanol is derived either from agricultural or cellulosic sources such as sugar cane, corn or decomposed plant matter. However, other fuels, such as butanol, have also arisen as potential candidates due to their similarities to gasoline, e.g. higher energy density than ethanol. To extract the maximum benefits from these new fuels through optimized engine design and calibration, an understanding of the behaviour of these fuels in modern engines is necessary. In particular, the use of direct injection spark-ignition technology requires spray formation and combustion characteristics to be quantified in order to improve both injector design and operating strategies. To this end an optical investigation of spray development and combustion was undertaken in a single-cylinder direct-injection spark-ignition engine with a centrally mounted multi-hole injector. Specifically, crank-angle resolved imaging studies were performed and batches of images from 100 consecutive cycles were acquired with synchronised in-cylinder pressure logging. The engine was motored and fired at 1500 RPM stoichiometrically under part load (0.5 bar intake pressure), with injection timing set early in the intake stroke to promote homogeneous mixture formation. The effects were investigated at engine coolant temperatures of 20 °C and 90 °C using gasoline, iso-octane, ethanol and butanol. Projected spray areas as seen through the piston crown were calculated to reveal information about the atomization and evaporation processes for each fuel. Additionally, flame areas and centroids were calculated to analyse the combustion process relative to measured in-cylinder pressure histories.

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“…7. In general, air entrainment in the spray plumes can be divided in to two regimes; (1) in the region closer to the nozzle exit air is drawn in and (2) the air and vapor mixture is pushed downstream towards the spray tip (Prosperi, Helie et Bazile 2007) and (Skogsberg, et al 2005). Both of these two regimes can be observed here as towards the nozzle exit vapor is being drawn inwards in first phase and forced downwards towards the spray tip as shown in Fig.…”

Section: Axial Gas Velocitymentioning

confidence: 99%

“…One such investigation is carried out by (Seibel, et al 2003) using for gasoline direct injection annular orifice spray. Another experimental study regarding multihole GDI injector highlights the fact that vapour accumulates inside the spray cone (Skogsberg, et al 2005). However it fails to illustrate the reason of vapour accumulation and its effects on the behaviour of the GDI spray.…”

Section: Introductionmentioning

confidence: 99%

Air Entrainment in High Pressure Multihole Gasoline Direct Injection Sprays

Khan¹,

Hélie²,

Gorokhovski³

et al. 2017

JAFM

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Experimental and numerical investigation of multihole gasoline direct injection (GDI) sprays at high injection pressure and temperature are performed. The primary objective of this study is to analyse the role of gas entrainment and spray plume interactions on the global spray parameters like spray tip penetration, spray angles and atomization. Three-hole 90° spray cone angle and six-hole 60° spray cone angle injectors are used for current work to examine the effect of the geometry of the injector on the spray interactions. The numerical results from Reynolds Average Navier Stokes (RANS) simulations show a reasonable comparison to experiments. The simulations provide further insight to the gas entrainment process highlights the fact that a stagnation plane is formed inside the spray cone which basically governs the semi collapse of spray that in turn affects the spray direction and cone angle.

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Effects of Injector Parameters on Mixture Formation for Multi-Hole Nozzles in A Spray-Guided Gasoline DI Engine

Cited by 43 publications

References 4 publications

Spray Development, Flow Interactions and Wall Impingement in a Direct-Injection Spark-Ignition Engine

Spray Development, Flow Interactions and Wall Impingement in a Direct-Injection Spark-Ignition Engine

Characteristics of Ethanol, Butanol, Iso-Octane and Gasoline Sprays and Combustion from a Multi-Hole Injector in a DISI Engine

Air Entrainment in High Pressure Multihole Gasoline Direct Injection Sprays

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