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Viewing 1 to 30 of 4498
2015-09-29
Technical Paper
2015-01-2814
Rakhesh Bharathan
Simultaneous reduction of NOx and PM from engine exhaust of a diesel engine is an interesting area of research due to the implementation of stringent emission regulations all over the world. Cost involved in expensive after treatment systems such as DPF and SCR necessitate minimization of engine out pollutants. With minimum engine out emission achieved through engine hardware and combustion parameter optimization, possibility of elimination or downsizing of the after treatment system can be explored. The paper presents the effect of fuel injection parameters and EGR rate on exhaust emission of a boosted diesel engine. Effects of parameters such as rail pressure, pilot-post injections, SOI, EGR rate and EGR temperature on a 4 cylinder two valve direct injection diesel engine is studied. Present study reveals the possibility of elimination of after treatment systems at BS IV level with optimization of engine hardware and combustion parameters.
2015-09-28 ...
  • September 28, 2015 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
  • April 15, 2016 (8:30 a.m. - 4:30 p.m.) - Detroit, Michigan
Training / Education Classroom Seminars
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.
2015-09-06
Technical Paper
2015-24-2475
Donghoon Kim, Choongsik Bae, Stephen Park
Three visualization methods, Schlieren, Shadowgraph, Mie-scattering, were applied to compare diesel and gasoline spray structures. Fuels were injected into the high pressure/high temperature chamber under the same in-cylinder pressure and temperature condition of low load in a GDCI (gasoline direct injection compression ignition) engine. Two injection pressures (20 and 40 MPa), two ambient pressures (4.2MPa and 1.7 MPa) and two ambient temperature (908 K and 677 K) were selected. Three images from different methods were overlapped to show liquid and vapor phases more clearly. Vapor development of two fuels were similar, but different liquid developments were shown. At the same injection pressure and ambient temperature, gasoline liquid propagated more shortly and disappeared rapidly than diesel liquid phase. At the low ambient temperature and pressure condition, gasoline and diesel sprays with higher injection pressure showed a longer liquid length due to higher spray momentum.
2015-09-06
Technical Paper
2015-24-2428
Ferdinando Taglialatela Scafati, Francesco Pirozzi, Salvatore Cannavacciuolo, Luigi Allocca, Alessandro Montanaro
Gasoline direct injection (GDI) combustion with un-throttled lean stratified operation allows to reduce engine toxic emissions and achieve significant benefits in terms of fuel consumption. However, use of gasoline stratified charges can lead to several problems, such as a high cycle-to-cycle variability and increased particle emissions. Use of multiple injection strategies allows to mitigate these problems, but it requires the injection of small fuel amounts forcing the traditional solenoid injectors to work in their “ballistic” region, where the correlation between coil energizing time and injected fuel amount becomes highly not linear. In the present work a closed-loop control system able to manage the delivery of small quantities of fuel has been introduced. The control system is based on a particular feature found on the coil voltage command signal during the de-energizing phase.
2015-09-06
Technical Paper
2015-24-2467
Alessandro Ferrari, Federica Paolicelli
Abstract A challenging task that is required to modern injection systems is represented by the enhanced control of the injected quantities, especially when small injections are considered, such as, pilot and main shots in the context of multiple injections. The propagation of the pressure waves triggered by the nozzle opening and closure events through the high-pressure hydraulic circuit can influence and alter the performance of the injection apparatus. For this reason, an investigation of the injection system fluid dynamics in the frequency domain has been proposed. A complete lumped parameter model of the high-pressure hydraulic circuit has been applied to perform a modal analysis. The visualization of the main vibration modes of the apparatus allows a detailed and deep comprehension of the system dynamics. Furthermore, the possible resonances, which are induced by the action of the external forcing terms, have been identified.
2015-09-06
Technical Paper
2015-24-2470
Daniel Pearce, Yannis Hardalupas, A.M.K.P Taylor
The measurement of the rate of fuel injection using a constant volume, fluid filled chamber and measuring the pressure change as a function of time due to the injected fluid (the so called “Zeuch” method) is an industry standard due to its simple theoretical underpinnings. Such a measurement device is useful to determine key timing and quantity parameters for injection system improvements to meet the evolving requirements of emissions, power and economy. This study aims to further the understanding of the nature of cavitation which could occur in the near nozzle region under these specific conditions of liquid into liquid injection using high pressure diesel injectors for heavy duty engines. The motivation for this work is to better understand the temporal signature of the pressure signals that arise in a typical injection cycle.
2015-09-06
Technical Paper
2015-24-2473
Alessandro Montanaro, Luigi Allocca, Giovanni Meccariello, Maurizio Lazzaro
Abstract In internal combustion engines, the direct injection at high pressures produces a strong impact of the fuel on the combustion chamber wall, especially in small-bore sizes used for passenger cars. This effect is relevant for the combustion process resulting in an increase of the pollutant emissions and in a reduction of the engine performances. This paper aims to report the effects of the injection pressure and wall temperature on the macroscopic behavior and atomization of the impinging sprays on the wall. The gasoline spray-wall interaction was characterized inside an optically accessible quiescent chamber using a novel make ready Z-shaped schlieren-Mie scattering set-up using a high-speed C-Mos camera as imaging system. The arrangement was capable to acquire alternatively the schlieren and Mie-scattering images in a quasi-simultaneous fashion using the same line-of-sight.
2015-09-06
Technical Paper
2015-24-2480
Lucio Postrioti, Maurizio Bosi, Andrea Cavicchi, Fakhry AbuZahra, Rita Di Gioia, Giovanni Bonandrini
Direct Injection technology for Spark Ignition engines is currently undergoing a significant development process in order to achieve its complete potential in terms of fuel conversion efficiency, while preserving the ability to achieve future, stringent emission limits. In this process, improving the fuel spray analysis capabilities is of primary importance. Among the available experimental techniques, the momentum flux measurement is one of the most interesting approaches as it allows a direct measurement of the spray-air mixing potential and hence it is currently considered an interesting complement to spray imaging and Phase Doppler Anemometry. The aim of the present paper is to investigate the fuel spray evolution when it undergoes flash boiling, a peculiar flow condition occurring when the ambient pressure in which the spray evolves is below the saturation pressure of the injected fluid.
2015-09-06
Technical Paper
2015-24-2477
Ezio Mancaruso, Renato Marialto, Luigi Sequino, Bianca Maria Vaglieco, Massimo Cardone
Abstract Blends of propane-diesel fuel can be used in direct injection diesel engines to improve the air-fuel mixing and the premixed combustion phase, and to reduce pollutant emissions. The potential benefits of usinf propane in diesel engines are both environmental and economic; furthermore, its use does not require changes to the compression ratio of conventional diesel engines. The present paper describes an experimental investigation of the injection process for different liquid preformed blends of propane-diesel fuel in an optically accessible Common Rail diesel engine. Slight modifications of the injection system were required in order to operate with a blend of propane-diesel fuel. Pure diesel fuel and two propane-diesel mixtures at different mass ratios were tested (20% and 40% in mass of propane named P20 and P40). First, injection in air at ambient temperature and atmospheric pressure were performed to verify the functionality of the modified Common Rail injection system.
2015-09-06
Technical Paper
2015-24-2395
Xavier Tauzia, Alain Maiboom, Guanqin Ma
In this paper, a new 1D combustion model is presented. It is expected to combine good predictive capacities with a contained CPU time, and could be used for engine design. It relies on a eulerian approach, based on Musculus 1D transient spray model. The latter has been extended to model vaporizing, reacting sprays. The general features of the model are first presented. Then various sub models (spray angle and dilatation, vaporization, thermodynamic properties) are detailed. Chemical kinetics are described with a global scheme to keep computational time low. The spray discretization (mesh) and angle model are first discussed through a sensitivity analysis. The model results are then compared to experiments from ECN data base (SANDIA) realized in constant volume bombs, for both inert and reacting cases. Some detailed analysis of model results are performed, including comparisons of vaporizing and non-vaporizing cases, as well as inert and reacting cases.
2015-09-06
Technical Paper
2015-24-2406
Gyujin Kim, Kyoungdoug Min
Abstract The flamelet model is a widely used combustion model that demonstrates a good prediction of non-premixed combustion. In this model, the chemical time scales are considered to be smaller compared to those of the turbulence, which allows the heat and mass transfer equation to be decoupled from the flow equation. However, the model's dependency on the mixture fraction limits the combustion analysis to a single injection. To overcome this limitation, a two dimensional flamelet model, which uses two mixture fraction variables, was introduced to represent the non-premixed combustion of multiple injections. However, the model's computational time drastically increased due to the expansion of the solution domain. Thus, a modified 2-D flamelet model was introduced to reduce the computational time of the two dimensional flamelet model.
2015-09-06
Technical Paper
2015-24-2411
Carmelina Abagnale, Maria Cristina Cameretti, Umberto Ciaravola, Raffaele Tuccillo, Sabato Iannaccone
The dual-fuel (diesel/natural gas, NG) concept represents a solution to reduce emissions from diesel engines by using natural gas as an alternative fuel. As well known, the dual-fuel technology has the potential to offer significant improvements in the emissions of carbon dioxide from light-duty compression ignition engines. A further important requirement of the DF operation in automotive engines is a satisfactory response in a wide range of load levels. In particular, the part-load levels could present more challenging conditions for an efficient combustion development, due to the poor fuel/air ratio. Basing on the above assumptions, the authors discuss in this article the results of a combined numerical and experimental study on the effect of different injection timings on performance and pollutant fractions of a common rail diesel engine supplied with natural gas and diesel oil.
2015-09-06
Technical Paper
2015-24-2408
Nicola Giovannoni, Sebastiano Breda, Stefano Paltrinieri, Alessandro D'Adamo, Stefano Fontanesi, Francesco Pulvirenti
Abstract In spark-ignited direct-injected engines, the formation of fuel pools on the piston is one of the major promoters of unburnt hydrocarbons and soot: in order to comply with the increasingly stringent emission regulations (EU6 and forthcoming), it is therefore necessary to limit fuel deposit formation. The combined use of advanced experimental techniques and detailed 3D-CFD simulations can help to understand the mechanisms driving fuel pool formation. In the paper, a combined experimental and numerical characterization of pool formation in a GDI engine is carried out to investigate and understand the complex interplay of all the mentioned factors. In particular, a low-load low-rpm engine operation is investigated for different ignition phasing, and the impact of both fuel formulation and instantaneous piston temperature variations in the CFD analyses are evaluated.
2015-09-06
Technical Paper
2015-24-2398
Ivan Arsie, Roberto Di Cianni, Rocco Di Leo, Cesare Pianese, Matteo De Cesare
Abstract Nowadays the high competition reached by the automotive market forces Original Equipment Manufacturers (OEMs) towards innovative solutions. Strict emission standards and fuel economy targets make the work hard to be accomplished. Therefore modern engines feature complex architecture and embed new devices for Exhaust Gas Recirculation (EGR), turbocharging (e.g. multi-stage compressors), gas after-treatment (e.g. the Selective Catalyst Reduction (SCR)) and fuel injection (either high or low pressure). In this context the Engine Management System (EMS) plays a fundamental role to optimize engine operation. The paper deals with fuel spray and combustion simulation by a multi-zone phenomenological model aimed at the steady-state optimal tuning of the injection pattern.
2015-09-06
Technical Paper
2015-24-2413
Michela Costa, Francesco Catapano, Guido Marseglia, Ugo Sorge, Paolo Sementa, Bianca Maria Vaglieco
Abstract Gasoline direct injection (GDI) allows flexible operation of spark ignition engines for reduced fuel consumption and low pollutants emissions. The choice of the best combination of the different parameters that affect the energy conversion process and the environmental impact of a given engine may either resort to experimental characterizations or to computational fluid dynamics (CFD). Under this perspective, present work is aimed at discussing the assessment of a CFD-optimization (CFD-O) procedure for the highest performance of a GDI engine operated lean under both single and double injection strategies realized during compression. An experimental characterization of a 4-stroke 4-cylinder optically accessible engine, working stratified lean under single injection, is first carried out to collect a set of data necessary for the validation of a properly developed 3D engine model.
2015-09-06
Technical Paper
2015-24-2455
Slavey Tanov, Zhenkan Wang, Hua Wang, Mattias Richter, Bengt Johansson
Abstract Partially premixed combustion (PPC) is used to meet the increasing demands of emission legislation and to improve fuel efficiency. With gasoline fuels, PPC has the advantage of a longer premixed duration of the fuel/air mixture, which prevents soot formation. In addition, the overall combustion stability can be increased with a longer ignition delay, providing proper fuel injection strategies. In this work, the effects of multiple injections on the generation of in-cylinder turbulence at a single swirl ratio are investigated. High-speed particle image velocimetry (PIV) is conducted in an optical direct-injection (DI) engine to obtain the turbulence structure during fired conditions. Primary reference fuel (PRF) 70 (30% n-heptane and 70% iso-octane) is used as the PPC fuel. In order to maintain the in-cylinder flow as similarly as possible to the flow that would exist in a production engine, the quartz piston retains a realistic bowl geometry.
2015-09-06
Technical Paper
2015-24-2453
K Abdul Rahman, A Ramesh
In this experimental work the effect of double injection of diesel in a biogas-diesel partially premixed charge compression ignition (BDPPCCI) engine was studied. Biogas was inducted along with air while diesel was injected through a common rail system using an open electronic control unit. Experiments were done at a fixed brake mean effective pressure of 2 bar and an intake charge temperature of 40°C. The effect of start of injection (SOI) of first and second injection pulses and also the biogas energy share (BGES) were evaluated. Experiments were also done in the BDPPCCI mode with diesel being injected in a single pulse and in the biogas-diesel dual fuel (BDDF) mode for comparison. The thermal efficiency in the BDPPCCI mode was better with double injection of diesel as compared to single pulse injection due to better combustion phasing. Improved charge homogeneity and reduced wall wetting of diesel lowered the smoke emission levels with split injection.
2015-09-06
Technical Paper
2015-24-2454
Zhenkan Wang, Slavey Tanov, Hua Wang, Mattias Richter, Bengt Johansson, Marcus Alden
It has been proven that partially premixed combustion (PPC) has the capability of high combustion efficiency with low soot and NOx emissions, which meet the requirements of increasingly restricted emission regulations. In order to obtain more homogenous combustion and longer ignition delay in PPC, different fuel injection strategies were employed which could affect the fuel air mixing and control the combustion. In the present work, a light duty optical diesel engine was used to conduct high speed particle image velocimetry (PIV) for single, double and triple injections with different timings. A quartz piston and a cylinder liner were installed in the Bowditch configuration to enable optical access. The geometry of the quartz piston crown is based on the standard diesel combustion chamber design for this commercial passenger car engine, including a re-entrant bowl shape.
2015-09-06
Technical Paper
2015-24-2471
Federico Pellegrino, Alessio Dulbecco, Denis Veynante
Abstract This paper presents a phenomenological quasi-dimensional model of the processes that lead to charge preparation in a Direct-Injection Spark-Ignition (DI-SI) engine, focusing on the physics of atomization and drop evaporation, spray development and the mutual interaction between these phenomena. Atomization and drop evaporation are addressed by means of constant-diameter drop parcels, which provide a discrete drop-size distribution. A discrete Probability Density Function (PDF) approach to fuel/air mixing is proposed, based on constant-mixture-fraction classes that interact with each other and with the drop parcels. The model has been developed in the LMS Imagine.Lab Amesim™ system simulation platform for multi-physical modeling and integrated in a generic SI combustion chamber submodel, CFM1D [15], of the IFP-Engine library.
2015-09-06
Technical Paper
2015-24-2459
Francesco Catapano, Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco
Abstract The use of direct injection (DI) engines allows a more precise control of the air-fuel ratio, an improvement of fuel economy, and a reduction of exhaust emissions thanks to the ultra-lean combustion due to the charge stratification. These effects can be partially obtained also with an optimized Air Direct Injection that permits to increase the turbulence at low speed and load increasing the combustion stability especially in lean condition. In this paper, a gasoline PFI (named G-PFI), gasoline PFI-methane DI dual fuel (named G-MDF) lean combustion were analyzed. The G-MDF configuration was also compared with a gasoline PFI - air DI (named G-A) configuration in order to distinguish the chemical effect of methane from the direct injection physical effect. The tests were carried out in a small displacement PFI/DI SI engine. The experimental investigation was carried out in a transparent small single-cylinder, spark ignition four-stroke engine.
2015-09-06
Technical Paper
2015-24-2468
Kar Mun Pang, Hiew Mun Poon, Hoon Kiat Ng, Suyin Gan, Jesper Schramm
Abstract This work concerns the modelling of soot formation process in diesel spray combustion under engine-like conditions. The key aim is to investigate the soot formation characteristics at different ambient temperatures. Prior to simulating the diesel combustion, numerical models including a revised multi-step soot model is validated by comparing to the experimental data of n-dodecane fuel in which the associated chemistry is better understood. In the diesel spray simulations, a single component n-heptane mechanism and the multi-component Diesel Oil Surrogate (DOS) model are adopted. A newly developed C16-based model which comprises skeletal mechanisms of n-hexadecane, heptamethylnonane, cyclohexane and toluene is also implemented. Comparisons of the results show that the simulated liftoff lengths are reasonably well-matched to the experimental measurement, where the relative differences are retained to below 18%.
2015-09-06
Journal Article
2015-24-2464
Daniele Farrace, Ronny Panier, Martin Schmitt, Konstantinos Boulouchos, Yuri M. Wright
Large Eddy Simulations (LES) provide instantaneous values indispensable to conduct statistical studies of relevant fluctuating quantities for diesel sprays. However, numerous realizations are generally necessary for LES to derive statistically averaged quantities necessary for validation of the numerical framework by means of measurements and for conducting sensitivity studies, leading to extremely high computational efforts. In this context, the aim of this work is to explore and validate alternatives to the simulation of 20-50 single realizations at considerably lower computational costs, by taking advantage of the axisymmetric geometry and the Quasi-Steady-State (QSS) condition of the near nozzle flow at a certain time after start-of-injection (SOI).
2015-09-06
Journal Article
2015-24-2426
Roberto Finesso, Ezio Spessa, Mattia Venditti, Yixin Yang
Abstract New methodologies have been developed to optimize EGR rate and injection timing in diesel engines, with the aim of minimizing fuel consumption (FC) and NOx engine-out emissions. The approach entails the application of a recently developed control-oriented engine model, which includes the simulation of the heat release rate, of the in-cylinder pressure and brake torque, as well as of the NOx emission levels. The engine model was coupled with a C-class vehicle model, in order to derive the engine speed and torque demand for several driving cycles, including the NEDC, FTP, AUDC, ARDC and AMDC. The optimization process was based on the minimization of a target function, which takes into account FC and NOx emission levels. The selected control variables of the problem are the injection timing of the main pulse and the position of the EGR valve, which have been considered as the most influential engine parameters on both fuel consumption and NOx emissions.
2015-09-06
Journal Article
2015-24-2442
Guillaume Lequien, Zheming Li, Oivind Andersson, Mattias Richter
Abstract The influence of jet-flow and jet-jet interactions on the lift-off length of diesel jets are investigated in an optically accessible heavy-duty diesel engine. High-speed OH chemiluminescence imaging technique is employed to capture the transient evolution of the lift-off length up to its stabilization. The engine is operated at 1200 rpm and at a constant load of 5 bar IMEP. Decreasing the inter-jet spacing shortens the liftoff length of the jet. A strong interaction is also observed between the bulk in-cylinder gas temperature and the inter-jet spacing. The in-cylinder swirl level only has a limited influence on the final lift-off length position. Increasing the inter-jet spacing is found to reduce the magnitude of the cycle-to-cycle variations of the lift-off length.
2015-09-06
Technical Paper
2015-24-2466
Tim Lackmann, Alan R. Kerstein, Michael Oevermann
To further improve engines in terms of both efficiency and emissions many new combustion concepts are currently being investigated. Examples include homogeneous charge compression ignition (HCCI), stratified charge compression ignition (SCCI), lean stratified premixed combustion, and high levels of exhaust gas recirculation (EGR) in diesel engines. All of these combustion concepts have in common that the typical combustion temperatures are lower than in traditional spark ignition or diesel engines. To further improve and develop combustion concepts for clean and highly efficient engines, it is necessary to develop new computational tools that can be used to describe and optimize processes in non-standard conditions, such as low temperature combustion. Thus, in the presented study a recently developed model (RILEM: Representative Interactive Linear Eddy Model) for modeling non-premixed combustion, regime-independently, was used to simulate a spray combustion process.
2015-09-06
Journal Article
2015-24-2472
Nikolaos Papadopoulos, Pavlos Aleiferis
The design of a Diesel injector is a key factor in achieving higher engine efficiency. The injector's fuel atomisation characteristics are also critical for minimising toxic emissions such as unburnt Hydrocarbons (HC). However, when developing injection systems, the small dimensions of the nozzle render optical experimental investigations very challenging under realistic engine conditions. Therefore, Computational Fluid Dynamics (CFD) can be used instead. For the present work, transient, Volume Of Fluid (VOF), multiphase simulations of the flow inside and immediately downstream of a real-size multi-hole nozzle were performed, during and after the injection event with a small air chamber coupled to the injector downstream of the nozzle exit. A Reynolds Averaged Navier-Stokes (RANS) approach was used to account for turbulence. Grid dependency studies were performed with 200k-1.5M cells.
2015-09-06
Technical Paper
2015-24-2499
Fabio Berni, Sebastiano Breda, Alessandro D'Adamo, Stefano Fontanesi, Giuseppe Cantore
Abstract A new generation of highly downsized SI engines with specific power output around or above 150 HP/liter is emerging in the sport car market sector. Technologies such as high-boosting, direct injection and downsizing are adopted to increase power density and reduce fuel consumption. To counterbalance the increased risks of pre-ignition, knock or mega-knock, currently made turbocharged SI engines usually operate with high fuel enrichments and delayed (sometimes negative) spark advances. The former is responsible for high fuel consumption levels, while the latter induce an even lower A/F ratio (below 11), to limit the turbine inlet temperature, with huge negative effects on BSFC. A possible solution to increase knock resistance is investigated in the paper by means of 3D-CFD analyses: water/methanol emulsion is port-fuel injected to replace mixture enrichment while preserving, if not improving, indicated mean effective pressure and knock safety margins.
2015-09-06
Technical Paper
2015-24-2476
Christian Pötsch, Laura Sophie Baumgartner, Daniel Koch, Felix Bernhard, Bastian Beyfuss, Georg Wachtmeister, Donatus Wichelhaus
Alongside with the severe restrictions according to technical regulations of the corresponding racing series (air and/or fuel mass flow), the optimization of the mixture formation in SI-race engines is one of the most demanding challenges with respect to engine performance. Bearing in mind its impact on the ignition behavior and the following combustion, the physical processes during mixture formation play a vital role not only in respect of the engine's efficiency, fuel consumption, and exhaust gas emissions but also on engine performance. Furthermore, abnormal combustion phenomena such as engine knock may be enhanced by insufficient mixture formation. This can presumably be explained by the strong influence of the spatial distribution of the air/fuel-ratio on the inflammability of the mixture as well as the local velocity of the turbulent flame front.
2015-09-06
Technical Paper
2015-24-2478
Johannes Palmer, Mogan Ramesh, Valeri Kirsch, Manuel Reddemann, Reinhold Kneer
Abstract Targeted fuel blending is a known method to improve the performance of an automotive engine. Two candidates for a biofuel blend are the linear C8H18O isomers 1-octanol and di-n-butyl ether (DNBE). Both fuels feature an increased amount of oxygen that reduces soot emissions. However, physical properties of both fuels differ significantly and thus, a different type of spray mixing and combustion is expected: The low reactivity of 1-octanol causes a long ignition delay enabling a better mixture homogenization, but also causes HC and CO emissions. DNBE in contrary is highly volatile, has a short ignition time and thus can act as an ignition booster for 1-octanol without losing positive effects concerning emissions. In this work a spray study is performed for blends of 1-octanol and DNBE. Measurements are conducted under diesel-like engine conditions with an 8-hole piezo injector. High-speed Schlieren and Mie scattering techniques are used for spray visualizations.
2015-09-06
Journal Article
2015-24-2502
Yujun Liao, Panayotis Dimopoulos Eggenschwiler, Alexander Spiteri, Lorenzo Nocivelli, Gianluca Montenegro, Konstantinos Boulouchos
The injection process of urea-water solution (AdBlue) determines initial conditions for reactions and catalysis and is fundamentally responsible for optimal operation of selective catalytic reduction (SCR) systems. The spray characteristics of four, commercially available, injectors (one air-assisted and three pressure-driven with different nozzle-hole configurations) are investigated with non-intrusive measuring techniques. Injection occurred in the crossflow of a channel blowing preheated air in an exhaust duct similar configuration. The effect of several gas temperatures and flows on the spray propagation and entrainment has been extensively studied by shadow imaging. Shadow images, in addition, show that the spray of the pressure-driven injectors is only marginally affected by the gas crossflow. In contrast, the air assisted spray is strongly deflected by the gas, the effect increasing with increasing gas flow.
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