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Training / Education
2015-06-15
Liquid fuel atomization and spray formation is the heart of the majority of stationary and mobile power generation machines that we rely on. This seminar focuses on the process of liquid atomization and spray formation and how it relates to fuel injection systems and emission of pollutants in modern engines. The seminar begins with background coverage of terminology, the purposes of liquid atomization and spray formation, and different designs of atomizers and nozzles employed in various industries. The focus is then directed to gasoline and diesel fuel injections, injector designs, and performance requirements for optimum engine operation with lowest possible emission of harmful pollutants.
Event
2014-11-20
This session will focus on the unique requirements and challenges to optimize fuel delivery and combustion quality for small engine applications, due to wide ranging environmental conditions as well as fuel type and quality. It will include presentations related to fuel pumps, injectors and other components related to the delivery of the fuel from the tank to the engine as well as optimization of the combustion process, and will discuss systemic and component related issues.
Technical Paper
2014-11-11
Luigi Allocca, Alessandro Montanaro, Rita Di Gioia, Giovanni Bonandrini
In the next future, improvements of direct injection systems for spark-ignited engines are necessary for the potential reductions in fuel consumptions and exhaust emissions. The admission and spread of the fuel in the combustion chamber is strictly related to the injector design and performances, such as to the fuel and environmental pressure and temperature conditions. In this paper the spray characterization of a GDI injector under normal and flash-boiling injection conditions has been investigated. A customized sensing of the injector nose permitted the temperature control of the nozzle up to 90 °C while a remote-controlled thermostatic device allowed the fuel heating from ambient to 120 °C. An axially-disposed, 0.200 mm in diameter, single-hole injector has been used with l/d ratio equal to 1 and static flow@100 bar: 2.45 g/s, using iso-octane as mono-component fluid. A 1.0 ms duration single pulse strategy has been adopted at the injection pressure of 10 MPa. The spray evolved in a quiescent optically-accessible vessel pressurize at 0.05, 0.1 and 0.3 MPa at ambient temperature of the gas (N2).
Technical Paper
2014-11-11
John Walters, Francois Brun
Stringent emission legislation applied to small motorcycles and scooters forces gradually in the world, the replacement of Carburetor by Electronic Injection system. The integration of this new technology creates new constraints on the engine and also on the vehicle. This study will provide an overview of these constraints and also technical solutions to reduce the impact on engine and vehicle. A special focus will be done on the fuel system where the development of an advance technology will be discussed in detail. This technology marks a break with the standard automotive fuel system architecture in order to fulfill the specific requirement of scooters and small motorcycles: low size, low weight, low energy demand, simple to integrate. The discussion will disclose the advantages and drawback of different fuel system architecture, the detailed description of the technology selected to achieve the requirements, the modeling approach used for the calculation and fine tuning of the design and finally the performances achieved on bench and on vehicle in nominal and boundary conditions.
Training / Education
2014-11-07
The improved efficiencies of the modern diesel engine have led to its increased use within the mobility industry. The vast majority of these diesel engines employ a high-pressure common rail fuel injection system to increase the engine's fuel-saving potential, emissions reduction, and overall performance. This one-day seminar will begin with a review of the basic principles of diesel engines and fuel injection systems. Diesel and alternative fuels will be discussed, followed by current and emerging diesel engine applications. The majority of the day will be dedicated to the common rail system itself, beginning with a comprehensive overview of the complete system.
Event
2014-10-22
This session is devoted to experimental and computational work in the area of fuel injection systems and sprays. Topics include: spray characterization, cavitation, multi-phase jet modeling, CFD models for spray processes, wall films and impingement, hydraulic circuit analysis, and dissolved gas effects. Studies of both gasoline and diesel fuel sprays and fuel injection equipment are encouraged.
Event
2014-10-21
This session is devoted to experimental and computational work in the area of fuel injection systems and sprays. Topics include: spray characterization, cavitation, multi-phase jet modeling, CFD models for spray processes, wall films and impingement, hydraulic circuit analysis, and dissolved gas effects. Studies of both gasoline and diesel fuel sprays and fuel injection equipment are encouraged.
Event
2014-10-21
This session is devoted to experimental and computational work in the area of fuel injection systems and sprays. Topics include: spray characterization, cavitation, multi-phase jet modeling, CFD models for spray processes, wall films and impingement, hydraulic circuit analysis, and dissolved gas effects. Studies of both gasoline and diesel fuel sprays and fuel injection equipment are encouraged.
Event
2014-10-21
This session is devoted to experimental and computational work in the area of fuel injection systems and sprays. Topics include: spray characterization, cavitation, multi-phase jet modeling, CFD models for spray processes, wall films and impingement, hydraulic circuit analysis, and dissolved gas effects. Studies of both gasoline and diesel fuel sprays and fuel injection equipment are encouraged.
Event
2014-10-15
Technical Paper
2014-10-13
Mayank Mittal, Harold Schock
A single-cylinder gasoline direct-injection engine was used for fuel spray and combustion visualizations with optical access to the combustion chamber. Experiments were conducted to investigate the effect of fuel injection pressure on spray and combustion characteristics inside the engine cylinder. A multi-hole high-pressure production injector was used with fuel pressures of 5 and 10 MPa. A Mie scattering technique was used to image the liquid phase of the fuel dispersion. The obtained spray images were then used to study the macroscopic spray characteristics such as spray structure, spray tip penetration and spray angle. Combustion visualization tests were performed to evaluate the effect of fuel injection pressure on combustion characteristics. In-cylinder pressure signals were recorded for the combustion analyses and synchronized with the high-speed combustion imaging recording. Results showed that higher fuel injection pressure led to faster spray tip penetration and more spray area for better fuel-air mixing.
Technical Paper
2014-10-13
Zaira Aline Kuensch, Stephanie Schlatter, Karri Keskinen, Tuomo Hulkkonen, Martti Larmi, Konstantinos Boulouchos
Direct injection of natural gas in engines is considered a promising approach toward reducing engine out emissions and fuel consumption. As a consequence, new gas injection strategies have to be developed for easing direct injection of natural gas and its mixing processes with surrounding air. In this study, the behavior of a hollow cone gas jet generated by a piezoelectric injector was experimentally investigated by means of tracer-based planar laser-induced fluorescence (PLIF). Pressurized acetone-doped nitrogen was injected in a constant pressure and temperature measurement chamber with optical access. The jet was imaged at different timings after start of injection and its time evolution was analyzed as a function of injection pressure and needle lift. The acquired PLIF images provide quantitative information about temporal evolution of the transient gas jet in terms of penetration length and jet width, while they qualitatively describe spatial distribution in terms of local gas concentration, estimated average jet concentration and jet volume.
Technical Paper
2014-10-13
Romaeo Dallanegra, Rinaldo Caprotti
Internal Diesel Injector Deposits (IDIDs) have been known for some time. With the latest powertrains becoming ever more sophisticated and reliant on efficient fuel delivery, the necessity for a continued focus on limiting their formation remains. Initial studies probed both carbonaceous based/ashless polymeric and sodium salt based IDIDs. The reported occurrence of the latter variety of IDID has declined in recent years as a result of the removal of certain additives from the diesel distribution system. Conversely, ashless polymeric based deposits remain problematic and a regular occurrence in the field. The body of work presented in this contribution is an extension to that reported in SAE paper 2014-01-1401 which showed how a particular Fuel Borne Catalyst (FBC) additive has the ability to prevent the formation of ashless polymeric deposits formed from the reaction of Poly-Isobutylene Succinic Imides (PIBSI) with fatty acid and the ability for the same additive to also be neutral towards the formation of sodium salt based deposits.
Technical Paper
2014-10-13
Martin Krämer, Eberhard Kull, Markus Heldmann, Michael Wensing
Introduction Modern concepts of downsized DI gasoline engines set up high requirements on the injection system to meet the emission targets. The fundamental knowledge and understanding of spray propagation physics are essential for the development of nozzles and injection strategies, due to reduced displacements in combination with the continuing trend of elevated fuel pressures. The experimental results presented in this paper are carried out in a high pressure and high temperature injection chamber. Object of investigation is a GDI multihole injector, optically analyzed with imaging Shadowgraphy and Phase Doppler Anemometry (measurement planes at two distances from nozzle tip), for macro- and microscopic spray parameters. The results are used to discuss a phenomenological model of spray propagation and describe influence factors and possibilities to control penetration of gasoline sprays in a fuel pressure range up to 380bar. Results and Discussion The propagation behaviour of gasoline sprays can be divided in two parts.
Technical Paper
2014-10-13
Alessandro Ferrari, Pietro Pizzo, Federica Paolicelli
A numerical-experimental activity on the latest generation of solenoid Common Rail injectors with the pressure balanced pilot-valve has been carried out. This design solution has been recently introduced in the market in order to reduce fuel static leakages and improve both the efficiency and control of the solenoid CR technology. An experimental campaign has been performed at the hydraulic test rig to characterize the fuel leakages of the newly designed solenoid injector with respect to the injectors equipped with the standard pilot-valve layout and to the piezoelectric indirect-acting injectors that are claimed to feature reduced leakages. An accurate numerical model of the solenoid injector with the pressure balanced pilot-valve has been realized in order to better assess the cause and effect relationships between design changes and experimental performance. The one-dimensional model performance has been assessed by means of the comparison between numerical outcomes and experimental data, which refer to injected flow-rate and injector-inlet pressure time distributions and have been measured for single and multiple injection events.
Technical Paper
2014-10-13
Yuhan Huang, Sheng Huang, Peng Deng, Ronghua Huang, Guang Hong
Ethanol direct injection (EDI) is a new technology to make the use of ethanol fuel more effective and efficient in spark ignition engines. Fuel temperature is one of the key factors which determine the evaporation process of liquid fuel spray, and consequently influence the combustion and emission generation of the engine. To better understand the mixture formation process of the EDI spray and provide essential data for engine modelling, experiments were conducted on a constant volume combustion chamber in engine-like conditions. The high speed Shadowgraphy imaging technique was used to capture the ethanol spray behaviours. The experiments covered a wide range of fuel temperatures, ranging from 275K (non-evaporating) to 400K (flash-boiling). Particularly the transition of the ethanol spray from normal-evaporating to flash-boiling was investigated. The temporal Shadowgraphy spray images, spray tip penetration, angle and projected area were applied to evaluate the evaporation of EDI spray under different fuel temperature conditions.
Technical Paper
2014-10-13
Luca Marchitto, Simona Merola, Cinzia Tornatore, Gerardo Valentino
Alcohols are largely used in spark-ignition (SI) engines as alternative fuels to gasoline. Particularly, the use of n-butanol meets growing interest due to its properties that are similar to gasoline, if compared with other alcohols. This paper aims to make a comparative analysis on the atomization process of gasoline and n-butanol fuel injected by a multi-hole injector nozzle for spark ignition engines. Imaging and Phase Doppler Anemometry techniques were applied to investigate the behaviour of a spray emerging from a six-hole injector for spark ignition engine applications. Two different fuels were investigated: commercial gasoline and pure n-butanol. Fuels were injected at two pressures: namely at 5 and 10 MPa, in a test vessel at quiescent air conditions, ambient temperature and backpressure. Injection duration was set to deliver the same fuel mass for both fuels. Image sequences of the spray were collected by a high speed camera in order to characterize spatial-temporal evolution of the spray.
Technical Paper
2014-10-13
Alessandro Montanaro, Luigi Allocca, Ugo Sorge, Anqi Zhang, Michela Costa
Diesel sprays from an axial-disposed single-hole injector were studied under vaporizing conditions in a constant-volume combustion vessel. A hybrid Shadowgraph/Mie-scattering imaging setup was used to acquire the liquid and vapor phases of the fuel distribution in a near-simultaneous visualization mode by a high-speed camera (40,000 fps). Two geometries of the injector duct were used, identified with k-factors 0 and 1.5, having the exit-hole diameter of 0.1 mm and the ratio L/d =10. The studies were performed at 70, 120, and 180 MPa injection pressures, 25.37 kg/m3 ambient gas density, and the gas temperature in the vessel of 373/453 and 900 K for non-vaporizing and vaporizing conditions, respectively. The instantaneous positions of the front of the spray, extracted from the images and processed by an assessed software, defined the tip penetrations of the liquid and vapor phases at the various operating conditions. The FIRE-AVL provisional code was used to predict the jet behavior calibrating the sub-models with the experimental data.
Technical Paper
2014-10-13
Yoshimitsu Kobashi, Yusuke Kimoto, Satoshi Kato
Ethanol is a promising alternative to fossil fuels because it can be produced from biomass resources that are renewable. Due to the amount of production, however, the use would be limited to blends with other conventional fuels. Ethanol-fuel blends are azeotropic and have unique vaporization characteristics different from blends composed of aliphatic hydrocarbons, so that the authors have developed a numerical droplet vaporization model which takes into account the vapor-liquid equilibrium of azeotrope and, additionally, higher latent heat of vaporization (LHV) of ethanol. In the present study, an experimental validation of the developed vaporization model was made through a comparison of single droplet vaporization tests. Ethanol-n-heptane blends in which n-heptane is assumed to be a representative component of gasoline were used for the comparison. The trend of calculated droplet vaporization rates were in good agreement with that of the experimental data, in terms of the change in the mixing fraction.
Technical Paper
2014-10-13
Hiroshi Kawanabe, Sho Tanaka, Shota Yamamoto, Hirokazu Kojima, Takuji Ishiyama
Single-excite and dual fluorescence PLIF was applied to a diesel spray of two-component fuel with different boiling points. The spray was formed by injecting fuel into a constant volume vessel under high-temperature and high-pressure conditions. The fluorescence emitted from the two tracers for fuel was optically separated to measure the concentration of each component. Mixture formation was investigated based on concentration distributions of each fuel-component. The fuel concentration was derived based on the change in fluorescence intensity due to temperature and the assumption of adiabatic mixing of fuel and surrounding fluid. The change in mixture distribution due to the difference of vaporization characteristics was investigated. The results show that the two components basically distribute similarly. Concentration of the high boiling component becomes slightly higher upstream base region in a spray.
Technical Paper
2014-10-13
Tianyou Wang, Xiangzan Meng, Xiaochao Song, Ming Jia
It has been recognized that density, viscosity, surface tension, and volatility of liquid fuel are of great importance on the atomization and vaporization characteristics of biodiesel spray. This paper presents a comprehensive physical property prediction of biodiesel fuel for spray modeling with most recently developed property prediction models. The temperature-dependent properties of a soy methyl ester (SME) biodiesel were well predicted by the updated prediction methods. Then, the physical properties of the SME biodiesel were added into the KIVA-3V fuel library. By using the well predicted fuel properties, the spray behaviors of SME were successfully simulated by the KIVA-3V code under late-cycle post-injection, conventional diesel injection, and early-injection engine-relevant conditions. The simulation results agree reasonably well with the available experimental liquid penetrations under conditions of various ambient densities and temperatures. The different properties between diesel and SME fuels have pronounced effect on their different spray behaviors under the late-cycle post-injection conditions.
Technical Paper
2014-10-13
Dehao Ju, Tingting Zhang, Jin Xiao, Zhen Huang
This study is to compare and qualify the macroscopic spray characteristics of dimethyl ether (DME) and diesel actuated through a plain-orifice atomizer. A moderate injection pressure of 6.0 MPa was operated to produce “stable” sprays vertically into atmosphere in this work. In order to quantitatively investigate the flash-boiling atomization, the sprays actuated under atmospheric conditions were directly imaged at a frame rate of 12,000 fps and analyzed by the multi-threshold algorithm. The spray images were acquired at various times after the start of actuation using a high-speed visualization system. The light intensity level of the image implies the local relative mass concentration of droplets in the spray. The transient continuous spray cone angles were measured at each case. Transient contour plots of DME spray images at various thresholds were analyzed and compared with turbulent round jets of diesel. The relative mass concentration distributions and continuous cone angles of the sprays during the start, development and end periods of the atomization were discussed for two different sprays.
Technical Paper
2014-10-13
Markus Behringer, Pavlos Aleiferis, Dave OudeNijeweme, Paul Freeland
One of the latest advancements in injector technology is laser drilling of the nozzle holes. In this context, the spray formation and atomisation characteristics of gasoline, ethanol and 1-butanol were investigated for a 7-hole spark eroded injector and its ‘direct replacement’ Laser-drilled injector using optical techniques. In the first step of the optical investigation, high-speed spray imaging was performed in a quiescent injection chamber with global illumination using diffused Laser light. The images were statistically analyzed to obtain spray penetration, spray tip velocity and spray ‘cone’ angles. Furthermore, droplet sizing was undertaken using Phase Doppler Anemometry (PDA). A single spray plume was isolated for this analysis and measurements were obtained across the plume at a fixed distance from the nozzle exit. The droplet measurements were grouped into bins and maps were created showing droplet sizes and velocities against time and position during and post injection. All tests were performed at 120 bar fuel pressure, two injection chamber ‘back’ pressures (0.5 bar and 1 bar) and two injector temperatures (20 °C and 80 °C), to examine effects relevant to typical engine operating conditions with early intake stroke injection strategies, including fuel flash boiling.
Technical Paper
2014-10-13
Ogheneruona E. Diemuodeke, Ilai Sher
The theory of liquid jet instabilities has been developed under several assumptions, which include the assumption that the jets breakup processes are quasi-steady and isothermal. Accelerated liquid fuels are normally injected into an elevated combustion-chamber temperature to maintain a desirable homogeneous combustible mixture – liquid vapour and air. The accelerated jet breakup may be induced by cavitations, turbulent, hydrodynamic and aerodynamic forces interaction and variation in fluid properties. The absolute majority of studies have been devoted to the extensive study on some of the effects that cause jet instability and breakup, while others are still at their infant study. In particular, relatively few researchers have studied the combined effects of jet acceleration and non-isothermal condition on jet instability and breakup, despite its practical relevance in liquid fuel spray and combustion. Specifically, liquid fuel jets are highly transient under pulsed injection technique, which has been demonstrated to maintain better fuel economy and emissions reduction.
Technical Paper
2014-10-13
Tianyou Wang, Xiangzan Meng, Xiaochao Song, Ming Jia
Spray behaviors of pure biodiesel and its blend with conventional diesel have been substantially studied in the last decade. However, the studies on the spray behaviors of pure fatty acid methyl esters (FAMEs) are scarce. The primary components of most biodiesel fuels are methyl palmitate (C16:0), methyl stearate (C18:0), methyl oleate (C18:1), methyl linoleate (C18:2) and methyl linolenate (C18:3), and methyl laurate (C12:0) is also the dominant component of some biodiesels. In this study, the spray behaviors of the aforementioned six FAMEs in biodiesel fuels under engine-relevant conditions were numerically studied using the KIVA-3V code. The physical properties needed for spray modeling were predicted with most recently developed property prediction models and added into the fuel library of KIVA-3V. The transient behaviors of liquid penetrations and vaporization characteristics of these FAMEs were numerically studied under various engine-relevant conditions. Results showed that the esters of 18-carbon-atom acids have much longer liquid lengths than those of C16:0 and C12:0 with relatively shorter carbon chain length.
Technical Paper
2014-10-13
Daliang Jing, Hongming Xu, Shi-jin Shuai, Zhi Wang, Yanfei Li
Fuel spray atomization process is known to play a key role in affecting mixture formation, combustion efficiency and soot emissions in direct injection engines. The fuel spray CFD modeling technology can be an effective means to study and predict spray characteristics such as penetration, droplet size and droplet velocity, and as a consequence, to drastically reduce experimental work during the engine development process. For this reason, an accurate numerical simulation of the spray evolution process is imperative. Different approaches and various models based on aerodynamically induced breakup mechanism have been implemented to simulate spray atomization process in earlier studies, and the effects of turbulence and cavitation from the injector nozzle is recently being concerned increasingly by engine researchers. In this study, an enhanced turbulence and cavitation induced primary breakup model combining aerodynamic breakup mechanism is developed and applied into the Kiva 3V code. The proposed model improves the primary breakup accuracy by optimizing the turbulence induced breakup process, controlling the transition process of the primary and secondary breakups and employing a new child droplet size function and a new parent droplet size reduction rate.
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