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Viewing 91 to 120 of 43870
2017-09-04
Technical Paper
2017-24-0129
Vladimir Merzlikin, Svetlana Parshina, Victoria Garnova, Andrey Bystrov, Alexander Makarov, Sergey Khudyakov
The core of this paper is reduction of exhaust emission and increase of diesel efficiency due to application of microstructure ceramic semitransparent heat-insulating coatings (SHIC). The authors conducted experimental study of thermal state of internal-combustion engine piston head with a heat-insulating layer formed by plasma coating method. The paper presents physical and mathematical simulation of improved optical (transmittance, reflectance, absorption, scattering) and thermo radiative (emittance) characteristics determining optimal temperature profiles inside SHIC. The paper considers the effect of subsurface volumetric heating up and analyzes temperature maximum position inside subsurface of this coating. Decrease of SHIC surface temperature of the coated piston in comparison with temperature of traditional opaque heat-insulating coatings causes NOx emission reduction.
2017-09-04
Technical Paper
2017-24-0127
Lauretta Rubino, Dominic Thier, Torsten Schumann, Stefan Guettler, Gerald Russ
With the increasing number of engines utilizing direct fuel injection and the upcoming more stringent emission legislation, regulating not only particulate mass (PM) but particulate number (PN), emissions of Direct Injection Spark Ignition Engines (DISI) are becoming of increasing concern. Gasoline Particle Filters (GPF) represent a novel potential measure to reduce particle number emissions from DISI engines and are particularly effective in view of the tight particle number limits requirements at cold start and over RDE. Even if some learning from the development and application of particulate filters to diesel engines can be transferred to gasoline engines, the particulate consistence, the mass to number ratio and the temperature as well as the gas composition of gasoline engines are significant different to diesel engines. Therefore, there is the need to study the application of particulate filters to gasoline engines carefully.
2017-09-04
Technical Paper
2017-24-0126
Christian Zöllner, Dieter Brueggemann
The removal of particulate matter (PM) from diesel exhaust is necessary to protect the environment and human health. To meet the strict emission standards for diesel engines an additional exhaust aftertreatment system is essential. Diesel particulate filters (DPF) are established devices to remove emitted PM from diesel exhaust. But the deposition and the accumulation of soot in the DPF influences the filter back pressure and therefore the engine performance and the fuel consumption which is why a periodical regeneration through PM oxidation is necessary. The oxidation behavior should result in an effective regeneration mode that minimizes the fuel penalty and limits the temperature rise while maintaining a high regeneration efficiency. Excessive and fast regenerations have to be avoided as well as uncontrolled oxidations leading to damages of the filter and fuel penalty.
2017-09-04
Technical Paper
2017-24-0124
Michael Maurer, Peter Holler, Stefan Zarl, Thomas Fortner, Helmut Eichlseder
To fulfil the new European real driving emissions (RDE) legislation, the LNT operation strategy – especially for DeNOx events – has to be optimized to minimize NOx as well as CO and HC emissions. On one hand the DeNOx purges should be long enough to fully regenerate the lean NOx trap, on the other hand the purges should be as short as possible to reduce the fuel consumption penalty from rich mode. Fundamental experiments have been conducted on a synthetic-gas-test-bench, purposely designed to test LNT catalysts. This methodology allowed to remove NOx from the gasfeed after the lean storage phase. The actually reduced amount of NOx could be easily calculated from the NOx storage before a regeneration minus the NOx that was desorbed during the DeNOx event and afterwards thermally desorbed NOx. To show the effect of aging method on the regeneration characteristics, tests have been performed with a in a car endurance run aged LNT and a synthetic hydrothermally aged LNT.
2017-09-04
Technical Paper
2017-24-0125
Angelo Algieri, Pietropaolo Morrone, Jessica Settino, Teresa Castiglione, Sergio Bova
In the last years automotive researchers and manufacturers are focusing a large attention on the development and the optimisation of aftertreatment systems able to meet the ever more severe regulations on exhaust gas emissions. The scientific literature highlights that all the emission control systems require proper operating temperatures and an accurate flow control to guarantee reliable and effective processes. In particular, to assure the suitable thermal level for efficient treatments, the addition of supplemental fuel is often necessary, with a not negligible penalty on the global engine efficiency. To reduce this effect, innovative reversed flow converters have been proposed over the past few years. They are based on the cyclic inversion of the exhaust gas between the two system ends (active flow control). Conversely, unidirectional flow within the aftertreatment system represents the technical solution largely adopted in practice (passive flow control).
2017-09-04
Technical Paper
2017-24-0108
Alessandro Montanaro, Marianna Migliaccio, Luigi Allocca, Carlo Beatrice, Valentina Fraioli, Roberto Ianniello
The combustion efficiency in modern diesel engines strictly depends on the quality of the air-fuel mixing and, in turn, the quality of spray atomization process. The air-fuel mixing is strongly influenced by the injection pressure, the geometry of the nozzle and the hydraulic characteristics of the injector. In this context, outward-opening piezoelectric injectors are gaining popularity as a high efficient device because of its precise control of the fuel injected. In the present paper, a new concept of open nozzle spray was investigated being a possible application for diesel engines. The study concerns an experimental and numerical characterization of a spray generated through a prototype high-pressure hollow-cone nozzle (HCN).
2017-09-04
Technical Paper
2017-24-0107
Alessandro Montanaro, Luigi Allocca, Vittorio Rocco, Michela Costa, Daniele Piazzullo
Enhancement of i.c. engine performances in terms of fuel economy and environment and human health preservation is an increasing key factor of the research in recent times. Mainly, that is due to the more and more stringent European and worldwide regulations tending to limit pollutant emissions to carbon monoxide, unburned hydrocarbons, nitrogen oxide, and particulate matter. Development of direct injection strategy (DI) in spark ignition (SI) engines partially fulfilled these tasks, as they run at higher compression ratios, with respect to port fuel injection (PFI), and operating with different injection strategies, so a greatest control over the air-to-fuel ratio is achieved. However, today the engines’ complexity and the number of sub-systems have increased, so the traditional techniques used for their optimization are often inadequate for the required challenges of high power output and low environmental impact.
2017-09-04
Technical Paper
2017-24-0109
Nic Van Vuuren, Lucio Postrioti, Gabriele Brizi, Federico Picchiotti
ABSTRACT: Selective Catalytic Reduction (SCR) diesel exhaust aftertreatment systems are virtually indispensable to meet NOx emissions limits worldwide. These systems generate the NH3 reductant by injecting aqueous urea solution (AUS-32/AdBlue®/DEF) into the exhaust for the SCR NOx reduction reactions. Understanding the AUS-32 injector spray performance is critical to proper optimization of the SCR system. Specifically, better knowledge is required of urea sprays under operating conditions including those where fluid temperatures exceed the atmospheric fluid boiling point. Results were previously presented from imaging of an AUS-32 injector spray which showed substantial structural differences in the spray between room temperature fluid conditions, and conditions where the fluid temperature approached and exceeded 104º C and “flash boiling” of the fluid was initiated.
2017-09-04
Technical Paper
2017-24-0110
Lucio Postrioti, Giulio Caponeri, Giacomo Buitoni
In the current automotive scenario, Direct Gasoline Injection technology is quickly spreading in several markets due to its higher potential for the fulfillment of stringent CO2 emission regulations. The stringent efficiency targets achievement is enabled by engine downsizing and by stratified-charge combustion strategy implementation; both these technologies are based on direct injection technology. Consequently, the fuel injector represents one of the key components for present and next SI engines. Along with appropriate spray characteristics in terms of sizing and jets shape and penetration in the combustion chamber, an accurate instantaneous injection rate control is required particularly to actuate complex multi-event injector actuation strategies.
2017-09-04
Technical Paper
2017-24-0113
Ezio Mancaruso, Luigi Sequino, Bianca Maria Vaglieco, Maria Cristina Cameretti
The management of multiple injections in compression ignition (CI) engines is one of the most common way to increase engine performance by avoiding hardware modifications and after-treatment systems. Great attention is given to the profile of the injection rate since it controls the fuel delivery in the cylinder. The Injection Rate Shaping (IRS) isa new developed technique that aims to manage the quantity of injected fuel during the injection process via a proper definition of the injection timing (injection duration and dwell time). In particular, it consists in closer and centered injection events and in a split main injection with a very small dwell time. From the experimental point of view, the performance of an IRS strategy has been studied in an optical CI engine. In particular, liquid and vapor phases of the injected fuel have been acquired via visible and infrared imaging, respectively. Injection parameters, like penetration and cone angle have been determined and analyzed.
2017-09-04
Technical Paper
2017-24-0115
Martin Pechout, Jan Czerwinski, Martin Güdel, Michal Vojtisek-Lom
In this study, the combustion of butanol, neat and mixed with gasoline, was investigated on a 0.6 liter two-cylinder spark ignition engine with fully adjustable fuel injection and spark timing, coupled with an eddy current dynamometer. Two isomers of butanol, n-butanol and iso-butanol, were examined. Butanol can be produced from non-food renewable resources and is one of the fuels exploited in the search of energy security and independence and of replacement of fossil fuels. Compared to the traditionally used ethanol, butanol does not exhibit hygroscopic behaviour, is chemically less aggressive and has higher energy density. On other hand, different laminar burning velocity and higher boiling temperature of butanol, compared to gasoline, requires some countermeasures to keep the engine operation reliable and efficient.
2017-09-04
Technical Paper
2017-24-0116
Ekarong Sukjit, Pansa Liplap, Somkiat Maithomklang, Weerachai Arjharn
In this study, two oxygenated fuels consisting of butanol and diethyl ether (DEE), both possess same number of carbon, hydrogen and oxygen atom but difference functional group, were blended with the waste plastic pyrolysis oil to use in a 4-cylinder direct injection diesel engine without any engine modification. In addition, the effect of castor oil addition to such fuel blends was also investigated. Four tested fuels with same oxygen content were prepared for engine test, comprising DEE16 (84% waste plastic oil blended with 16% DEE), BU16 (84% waste plastic oil blended with 16% butanol), DEE11.5BIO5 (83.5% waste plastic oil blended with 11.5% DEE and 5% castor oil) and BU11.5BIO5 (83.5% waste plastic oil blended with 11.5% butanol and 5% castor oil). The results found that the DEE addition to waste plastic oil increased more emissions than the butanol addition at low engine operating condition.
2017-09-04
Technical Paper
2017-24-0117
Fabio Scala, Enzo Galloni, Gustavo Fontana
In this paper, the behavior of a downsized spark-ignition engine firing with alcohol/gasoline blends has been analyzed. In particular, different butanol-gasoline and ethanol-gasoline blends have been examined. All the alcohol fuels here considered are derived from biomasses. In the paper, a numerical approach has been followed. A one dimensional model has been tuned in order to simulate the engine operation when it is fueled by alcohol/gasoline mixtures. Numerous operating points, characterized by two different engine speeds and several low-medium load values, have been analyzed. The objective of the numerical analysis is determining the optimum spark advance for different alcohol percentages in the mixtures at the different engine operating points. Once the best spark timing has been selected, the differences, in terms of both indicated torque and efficiency, arising in the different kinds of fueling have been evaluated.
2017-09-04
Journal Article
2017-24-0118
Marius Zubel, Stefan Pischinger, Benedikt Heuser
Within the cluster of excellence “Tailor-Made Fuels from Biomass” at the RWTH Aachen University, two novel biogenic fuels, namely 1-octanol and its isomer dibutyl ether (DBE), were identified and extensively analyzed in respect of their suitability for Diesel engine combustion. Both biofuels feature very different properties, especially regarding their ignitability. In previous works of the research cluster, promising synthesis routes with excellent yields for both fuels were found, using lignocellulosic biomass as source material. Both fuels were investigated as pure components in optical and thermodynamic single cylinder engines. For 1-octanol at lower part load, almost no soot emission could be measured, while with DBE the soot emissions were only about a quarter of that with conventional Diesel fuel. At high part load, the soot reduction of 1-octanol was more than 50% and for DBE more than 80 % respectively.
2017-09-04
Technical Paper
2017-24-0119
Jos Feijen, Gerard Klink, Ed Jong, Andreas Schmid, Niels Deen, Michael Boot
Second generation biomass is an attractive renewable feedstock for transport fuels. Its sulfur content is generally negligible and the carbon cycle is reduced from millions to tens of years. One hitherto non-valorized feedstock are so-called humins, a residual product formed in the conversion of sugars to platform chemicals, such as hydroxymethylfurfural and methoxymethylfurfural, intermediates in the production of FDCA, a building block used to produce the polyethylene furanoate (PEF) bottle by Avantium. The focus of this study is to investigate the spray combustion behavior of humins as a renewable alternative for heavy fuel oil (HFO) under large two-stroke engine-like conditions in an optically accessible constant volume chamber.
2017-09-04
Technical Paper
2017-24-0121
Ivan Arsie, Giuseppe Cialeo, Federica D'Aniello, Cesare Pianese, Matteo De Cesare, Luigi Paiano
The demand for high NOx conversion efficiency and low tailpipe ammonia slip for urea-based selective catalytic reduction (SCR) systems has substantially increased in the past decade, as NOx emission legislations for Diesel engines are becoming more stringent than ever before. Model-based control strategies are fundamental to meet the dual objective of maximizing NOx reduction and minimizing NH3 slip in urea-SCR catalysts. In this paper, a control oriented model of a Cu-zeolite urea-selective catalytic reduction (SCR) system for automotive diesel engines is presented. The model is derived from a quasi-dimensional four-state model of the urea-SCR plant. In order to make it suitable for the real-time urea-SCR management, a reduced order one-state model has been developed, with the aim of capturing the essential behavior of the system with a low computational demand. The model estimates the relevant species (i.e. NO, NO2 and NH3) independently.
2017-09-04
Technical Paper
2017-24-0123
Christopher Eck, Futoshi Nakano
Small commercial vehicles (SCV) with Diesel engines require efficient exhaust aftertreatment systems to reduce the emissions while keeping the fuel consumption and total operating cost as low as possible. To meet current emission legislations in all cases, a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) and some NOx treatment device (e.g. a lean NOx trap or selective catalytic reduction, SCR) are required. Creating a cost-effective SCV also requires to keep the cost for the aftertreatment system as low as possible because the contribution to total vehicle cost is high. By using more sophisticated and more robust operating strategies and control algorithms, the hardware cost can be reduced. To keep the calibration effort at a low level, it is necessary to apply only algorithms which have a time-efficient calibration procedure. This paper will focus on the active regeneration of the DPF.
2017-09-04
Technical Paper
2017-24-0092
Francesco Catapano, Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco
Fuel depletion as well as the growing concerns on environmental issues prompt to the use of more environmental friendly fuels. The natural gas (CNG) is considered one of the most promising alternative fuel for engine applications because of the lower emissions. Nevertheless, recent studies highlighted the presence of ultrafine particle emissions at the exhaust of CNG engines. The present study aims to investigate the effect of CNG on particle formation and emissions when it was direct injected and when it was dual fueled with gasoline. The study was carried out on a transparent small displacement single cylinder SI engine. The engine was fueled with CNG and gasoline, both simultaneously and not. In particular, CNG and gasoline were direct injected in the combustion chamber. For dual fuel configuration, instead, the CNG was direct injected and the gasoline port fuel injected. In-cylinder 2D images of flame evolution were detected. The flame front propagation was calculated.
2017-09-04
Technical Paper
2017-24-0091
Hyun Woo Won, Alexandre Bouet, Joseph KERMANI, Florence Duffour
Reduce the CO2 footprint, limit the pollutant emissions and rebalance the ongoing shift demand toward middle-distillate fuels are major concerns for vehicle manufacturers and oil refiners. In this context, gasoline-like fuels have been recently identified as good candidate. Strait run naphtha, a refinery stream directly derived from the atmospheric crude oil distillation process, allows to reduce both NOx and particulate emissions when used in compression-ignition engines. CO2 benefits are also expected thanks to its higher H/C ratio and energy content compared to diesel. In previous studies, wide ranges of Cetane Number naphtha fuels have been evaluated and CN 35 naphtha fuel has been selected. The assessment and the choice of the required engine hardware adapted to this fuel, such as the compression ratio, bowl pattern, nozzle design and air-path technology have been performed on a light-duty single cylinder compression-ignition engine.
2017-09-04
Technical Paper
2017-24-0094
Guoqing XU, Yuri Martin Wright, Panagiotis Kyrtatos, Konstantinos Bardis, Michele Schiliro, Konstantinos Boulouchos
Ignition and combustion processes inside pre-chamber spark plugs employed in stationary gas engines exhibit considerably longer durations compared to conventional, open chamber ‘’G-type’’ capacitive discharge ignition systems. The strength and timing of the turbulent flame jets subsequently issuing into the main chamber strongly depend on the pre-chamber combustion process and, thus, high sensitivity with respect to the specific engine operating conditions it experienced. This poses considerable difficulties in optimizing engine operational conditions as well as controlling engine performance. This paper investigates the influence of engine operating conditions on the pre-chamber combustion event using both experimental and numerical methods. A miniaturized piezo-electric pressure transducer was designed and placed inside the engine cylinder head to record the pre-chamber inner volume pressure, in addition to conventional pressure indication inside the main chamber.
2017-09-04
Technical Paper
2017-24-0096
Laura Sophie Baumgartner, Stephan Karmann, Fabian Backes, Andreas Stadler, Georg Wachtmeister
Due to its molecular structure, methane provides several advantages as fuel for internal combustion engines. First, owing to the single carbon atom per molecule, a formation of particular matter becomes drastically more unlikely and second the carbon to hydrogen ratio of methane reduces the amount of carbon dioxide by 20 % at the same energy output. To cope with nitrogen oxide emissions a high level of excess air is beneficial, which on the other hand deteriorates the flammability and combustion duration of the mixture. One approach to meet these challenges and ensure a stable combustion process are fuel scavenged prechambers. The flow and combustion processes within these prechambers are highly influenced by the position, orientation, number and overall cross-sectional area of the orifices connecting the prechamber and the main combustion chamber.
2017-09-04
Technical Paper
2017-24-0093
Lorenzo Bartolucci, Stefano Cordiner, Vincenzo Mulone, Vittorio Rocco
The use of natural gas in internal combustion engines (ICEs) improves thermal efficiency and reduces exhaust emissions at lean mixture operating conditions. However, as the mixture is leaned out beyond the Lean Misfire Limit (LML), several technical problems are more likely to occur. The flame propagation speed gradually decreases, leading to a slower heat release, thus increasing the occurrence of misfiring and incomplete cycles. This gives in turn a steep increase of CO and UHC emissions, and of cycle-by-cycle variations. In order to limit the above-mentioned problems, several solutions have been proposed so far. Among them, the stratification or the partial stratification of the charge has been demonstrated to successfully extend the lean limit if compared with traditional lean burn engines. This result has been accomplished through the formation of a richer mixture in the vicinity of the spark plug location, improving the stability of the combustion and ignition processes.
2017-09-04
Technical Paper
2017-24-0098
Christophe Barro, Curdin Nani, Richard Hutter, Konstantinos Boulouchos
The operation of dual fuel engines, operated with natural gas as main fuel, offers the potential of substantial savings in CO2. Nevertheless, the operating map area where low pollutant emissions are produced is very narrow. Especially at low load, the raw exhaust gas contains high concentrations of unburned methane and, with high pilot fuel portions due to ignition limitations, also soot. The analysis of the combustion in those conditions in particular is not trivial, since multiple combustion modes are present concurrently. The present work focuses on the evaluation of the individual combustion modes of a dual fuel engine, operated with natural gas as main and diesel as pilot fuel, using a combustion model. The combustion has been split in two partwise concurrent combustion phases: the auto-ignition phase and the premixed flame propagation phase.
2017-09-04
Technical Paper
2017-24-0095
Zbynek Syrovatka, Michal Takats, Jiri Vavra
A low temperature combustion of extremely diluted charge enables to approach the limit thermal efficiency of a spark ignited combustion engine. Homogeneous mixture combustion with high air excess ratio, typically beyond the flammability limit of a conventional spark ignition system, enables to reduce NOx emissions in raw exhaust gas. On the other hand, the extremely lean mixture leads to a lower burning velocity, poor combustion stability, leading to high unburned hydrocarbons emissions. The paper presents an ongoing research and development activities on the scavenged pre-chamber ignition system for an automotive natural gas fueled engine. The experimental work have been performed in engine laboratory at steady state conditions on a gas engine with 102 mm bore and 120 mm stroke, converted to a single cylinder engine. The in-house designed scavenged pre-chamber is equipped with a miniature pressure sensor for detailed combustion diagnostics.
2017-09-04
Technical Paper
2017-24-0097
Epaminondas Mastorakos, Patton Allison PhD, Andrea Giusti PhD, Pedro De Oliveira, Sotiris Benekos, Yuri M. Wright, Christos Frouzakis PhD, Konstantinos Boulouchos
A combined modelling and experimental investigation of the turbulent jet ignition system has been undertaken in a specially-designed flow rig (constant-pressure chamber) with the aim to identify the key physical processes occurring in this promising technology for natural gas engines. Performing this research at atmospheric pressures allows optical access that is difficult to achieve in a realistic engine environment. Various aspects such as: the nature of the fluid escaping the pre-chamber (i.e. unburnt, partially-burnt, fully-burnt); the probability of ignition of the mixture in the main chamber; the effects of geometrical parameters such as nozzle diameter and shape and chamber length; and the effect of flow in the main chamber and of mixture strength in both chambers, are systematically studied. Diagnostics include schlieren and OH* and CH* chemiluminescence imaging, and OH and CH2O planar laser-induced fluorescence.
2017-09-04
Technical Paper
2017-24-0099
Francesco Catapano, Paolo Sementa, Bianca Maria Vaglieco
Gasoline direct injection (GDI) allows knock tendency reduction in spark-ignition engines mainly due to the cooling effect of the in-cylinder fuel evaporation. However, the charge formation and thus the injection timing and strategies deeply affect the flame propagation and consequently the knock occurrence probability and intensity. Present work investigates the tendency to knock of a GDI engine at 1500 rpm full load under different injection strategies, single and double injections, obtained delivering the same amount of gasoline in two equal parts, the first during intake, the second during compression stroke. In these conditions, conventional and non-conventional measurements are performed on a 4-stroke, 4-cylinder, turbocharged GDI engine endowed of optical accesses to the combustion chamber.
2017-09-04
Technical Paper
2017-24-0102
Balasubramanian N, Jayabalan Sethuraman, Titus Iwaszkiewicz
In this paper, two different concepts of fuel-pumping methods using solenoid, for gasoline injection in engines, are discussed. The fuel pump is integrated within injector and thus makes the fueling system, simple, compact and less expensive. This integrated gasoline pump injector (GPI) is aimed at catering to the upcoming stringent emission norms, as it enables the usage of closed-loop fuel correction with the help of an electronic control unit (ECU), based on the exhaust lambda feedback. A solenoid and spring arrangement is used in this injector design, where the fuel gets pressurized in a pumping chamber, and the pressurized fuel is then injected through orifices to produce spray in the intake port. Two concepts are used for pressurizing the fuel. First concept uses a spring to pump the fuel and a solenoid to retract the plunger. Second concept uses solenoid to pump the fuel and spring to retract the plunger.
2017-09-04
Technical Paper
2017-24-0104
Daniel M. Nsikane, Kenan Mustafa, Andrew Ward, Robert Morgan, David Mason, Morgan Heikal
The Direct Numerical Simulation (DNS) approach to solving the fundamental transport equations down to the smallest scales of motion is favourable should the requirement be a truly predictive solution of fluid dynamic problems, but the simulation run times are unacceptable for most practical industrial applications. Despite the steadily increasing computational capabilities, Reynolds Averaged Navier-Stokes (RANS) based frameworks remain the only commercially viable option. The sub models within RANS simplify the description of key physical phenomena and include several numerical constants. These so-called “tuning constants” introduce multivariable dependencies that are almost impossible to untangle with local sensitivity studies. This paper addresses the prevailing difficulties in setting up an adequate Diesel spray simulation which arise from the mentioned multi-variable interactions of these “tuning constants”, by applying a statistical approach named Design of Experiments (DoE).
2017-09-04
Technical Paper
2017-24-0101
Pedro Marti-Aldaravi, Kaushik Saha, Jaime Gimeno, Sibendu Som
Actual combustion strategies in internal combustion engines rely on fast and accurate injection systems to be successful. One of the injector designs that has shown good performance over the past years is the direct-acting piezoelectric. This system allows precise control of the injector needle position and so the injected mass flow rate. Therefore, understanding how nozzle flow characteristics change as function of needle dynamics helps to choose the best lift law in terms of delivered fuel for a determined combustion strategy. Computational Fluid Dynamics is a useful tool for this task. In this work, nozzle flow of a prototype direct-acting piezoelectric has been simulated by using CONVERGE v2.3.10. Unsteady Reynolds-Averaged Navier-Stokes approach is used to take into account the turbulence. Simulations are able to properly capture the relationship between instantaneous partial needle lifts and the corresponding rate of injection.
2017-09-04
Technical Paper
2017-24-0106
Alessandro Montanaro, Luigi Allocca, Amedeo Amoresano, Giuseppe Langella
The reference parameters of sprays for i.c. engine are of macro-geometric type, like penetration, cone angle, or fluid dynamic one (velocity, particle size). In this work, the spray is assimilated to a dynamic system and defined through the time value of dynamic variables. The spray behavior is represented in a “phase diagram” that describes its operating points. The development of this methodology is carried out using experimental data of the spray evolution captured by a fast image acquisition system. An 8-hole ECN injector spraying iso-octane was chosen as a case study. It was characterized through the time variation of the cone angles, taken as dynamic discriminating variables of its behavior. Images were captured at high sampling rate and processed according to the theory of “ergodic” systems. Cone angles, derived from images and processed by neural networks algorithms, are represented in the “phase diagram” in order to detect stable behavior and not.
Viewing 91 to 120 of 43870