Criteria

Text:
Display:

Results

Viewing 61 to 90 of 110083
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
2017-24-0098
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
2017-24-0099
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
2017-24-0100
Panagiotis Kyrtatos, Antonio Zivolic, Clemens Brueckner, Konstantinos Boulouchos
Cycle-to-cycle variations in internal combustion engines are known to lead to limitations in engine load and efficiency, as well as increases in emissions. Cyclic variations are typically encountered in premixed, externally ignited engines as a result of the effect of turbulence on combustion, particularly during the early flame development. In compression ignition engines combustion is primarily spray-driven, and thus low cyclic variations are commonly expected. Recent research [1-3] has led to the identification of the source of cyclic variations of pressure, soot and NO emissions in direct injection common rail diesel engines, when employing a single block injection and operating under long ignition delay conditions. The variations in peak pressure arise from changes in the diffusion combustion rate, caused by randomly occurring in-cylinder pressure fluctuations.
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
2017-24-0102
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
2017-24-0103
Marlene Wentsch, Marco Chiodi, Michael Bargende
Main limiting factor in the application of 3D-CFD simulations within an engine development process is the very high time demand. The computing time of a 3D-CFD simulation is predominantly influenced by the number of cells within the computational mesh. An arbitrary cell coarsening, however, results in a distinct distortion of the simulation outcome. It is rather necessary to adapt the calculation models to the new mesh structure in order to ensure reliability and predictability of the 3D-CFD engine simulation. In the last decade, a fast response 3D-CFD tool was developed at FKFS in Stuttgart. It aims for a harmonized interaction between computational mesh, implemented calculation models and defined boundary conditions in order to enable fast running simulations for engine development tasks.
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
2017-24-0105
Stefania Falfari, Gian Marco Bianchi, Giulio Cazzoli, Claudio Forte PhD, Sergio Negro
The primary target of the internal combustion engines design is to lower the fuel consumption and to enhance the combustion process quality, in order to reduce the raw emission levels without performances penalty. In this scenario the direct injection system plays a key role for both diesel and gasoline engines. The spray dynamic behavior is crucial in defining the global and the local air index of the mixture, which in turns affects the combustion process development. At the same time the spray dynamic behavior is influenced by the cavitation process inside each single hole of the injector nozzle. The proper prediction of the cavitation development inside the injector nozzle holes is crucial in predicting the liquid jet emerging from them.
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.
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
2017-24-0108
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
2017-24-0109
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
2017-24-0111
Heechang Oh, JuHun Lee, Seungkook Han, Chansoo Park, Choongsik Bae, Jungho Lee, In Keun Seo, Sung Jae Kim
In this study, the effect of nozzle tip geometry on nozzle tip wetting and particulate emissions was investigated. Various design concepts of injector nozzle hole were newly developed for this study. Spray and emission characteristics of each concept were discussed with experimental results. The macroscopic spray visualization was carried out in a constant volume chamber to investigate general spray characteristics of each nozzle hole concept. The laser induced fluorescence technique was applied to evaluate fuel wetting characteristics on the nozzle tip. The vehicle test and emissions measurement in chassi dynamo were performed to investigate particulate emission characteristics for various injector nozzle designs. In addition, during a vehicle test, the in-cylinder combustion visualization with the optical fiber sensor (AVL VISIO VOLUME) was conducted to provide a comprehensive understanding of diffusion combustion and wetting behavior.
2017-09-04
Technical Paper
2017-24-0112
Guanyu Zheng
Urea injection is required in EU IV to EU VI applications as a mainstream technical direction. In heavy and some medium duty trucks, compressed air at 3-5 bar is available; therefore it can assist urea injection by mixing with urea liquid droplet and exhaust gases. The development of air assisted urea pump and injectors, seemly simpler than airless counterparts, poses multiple challenges. One challenge is to properly mix urea in the mixing chamber with the compressed air, leaving no residual deposits while achieving high mixing efficiency. Another is to maintain good spray quality for a given length of delivery pipe as the liquid phase and gas phase tends to coalesce as they propagate along the pipe flow direction. In addition, the urea pump and injector need to provide robust and reliable performance under stringent road conditions.
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
2017-24-0083
Hassan khatamnejad, Shahram Khalilarya, Samad Jafarmadar, Mostafa Mirsalim, Mufaddel Dahodwala
RCCI strategy gained popularity in automotive applications due to lower fuel consumption, less emissions formation and higher engine performance in compared with other diesel combustion strategies. This study presents results of an experimental and numerical investigation on RCCI combustion using natural gas as a low reactivity premixed fuel with advanced injection of diesel fuel as a high reactivity fuel in a CI engine. An advanced three dimensional CFD simulation coupled with chemical kinetic developed to examine the effects of diesel injection timing, diesel/natural gas ratio and diesel fuel included spray angle on combustion and emissions formation in various engine loads and speeds, in a heavy duty diesel engine.
2017-09-04
Technical Paper
2017-24-0082
Muhammad Umer Waqas, Nour Atef, Eshan Singh, Jean-Baptiste MASURIER, Mani Sarathy, Bengt Johansson
It is well established that the blending of ethanol with gasoline and primary reference fuels (PRFs) causes non-linear octane response. The chemical effect possibly responsible for the non-linear behavior remains to be understood. Previously, experiments were performed on Cooperative Fuel Research engine. Ethanol was added in volume percentage of 2-20% to five base fuels: three FACE (Fuels for Advanced Combustion Engines) gasolines, more specifically FACE I, J and A and their primary reference fuels (iso-octane/n-heptane). The engine was operated in HCCI mode for four different sets of speed and intake temperatures to obtain four HCCI numbers and their corresponding blending octane numbers. It was found that base fuel composition and octane number had an important role in the octane enhancement behavior of ethanol and methanol.
2017-09-04
Technical Paper
2017-24-0084
Giacomo Belgiorno, Nikolaos Dimitrakopoulos, Gabriele Di Blasio, Carlo Beatrice, Martin Tuner, Per Tunestal
In this paper, a parametric analysis on the main engine calibration parameters applied on gasoline Partially Premixed Combustion (PPC) is performed. Theoretically, the PPC concept permits to improve both the engine efficiencies and the NOx–soot trade-off simultaneously compared to the conventional diesel combustion. This work is based on the design of experiments (DoE), statistical approach, and investigates on the engine calibration parameters that might affect the efficiencies and the emissions of a gasoline PPC. The full factorial DoE analysis based on three levels and three factors (33 factorial design) is performed at three engine operating conditions of the Worldwide harmonized Light vehicles Test Cycles (WLTC). The pilot quantity (Qpil), the crank angle position when 50% of the total heat is released (CA50), and the exhaust gas recirculation (EGR) factors are considered. The goal is to identify an engine calibration with high efficiency and low emissions.
2017-09-04
Technical Paper
2017-24-0085
Jesus Benajes, Antonio Garcia, Javier Monsalve-Serrano, Vicente Boronat
This work investigates the particulates size distribution of reactivity controlled compression ignition combustion, a dual-fuel concept which combines port fuel injection of low reactive/gasoline-like fuels with direct injection of diesel fuel, when implemented in a medium-duty diesel engine. The particulates size distribution measurement was also carried out for conventional diesel combustion at six engine speeds, from 950 to 2200 rpm, and 25% engine load. For this purpose, a scanning mobility particle sizer was used to measure the particles size distribution from 5-250 nm. Both combustion strategies were conducted in a single-cylinder engine derived from a stock medium-duty multi-cylinder production engine with a compression ratio of 15.3. The combustion strategy proposed during the tests campaign was limited to accomplish mechanical as well as emissions constraints.
2017-09-04
Technical Paper
2017-24-0086
Yanzhao An, S vedharaj, R vallinayagam, Alaaeldin Dawood PhD, Jean-Baptiste MASURIER, Mohammad Izadi Najafabadi, Bart Somers, Junseok Chang, Bengt Johansson
Compared to conventional Compression Ignition (CI), both of Homogeneous Charge Compression Ignition (HCCI) and Partially Premixed Combustion (PPC) concepts have shown high efficiency with low soot emissions. However, soot measurements are rarely investigated and correlated with in-cylinder combustion in an optical diesel engine. The objective of this study is to investigate the effect of addition of toluene (aromatic) to primary reference fuel, PRF60, on combustion stratification and particulate emissions. Experiments are performed in an optical CI engine at a speed of 1200 rpm for TPRF0 (60% iso-octane + 40% n-heptane), TPRF20 (33.5% iso-octane + 46.5% n-heptane + 20% toluene) and TPRF40 (6% iso-octane + 54% n-heptane + 40% toluene). TPRF mixtures are prepared in such a way that the RON of all test blends are same (RON = 60) to account for the influence of aromatics in TPRF mixtures. The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar.
2017-09-04
Technical Paper
2017-24-0087
Maxime Pochet, Ida Truedsson, Fabrice Foucher, Hervé Jeanmart, Francesco Contino
Ammonia and hydrogen can be produced from water, air and excess electricity using power-to-fuel and are therefore a promising step in the transition from fossil fuel energy to cleaner energy sources. Indeed, produced from excess renewable electricity these two fuels can provide mid- and long-term energy storage. An HCCI engine can be used to convert those two energy vectors to electricity and heat. The purpose of the study was to see the possible range of ammonia concentrations that could be used in a conventional 16:1 compression ratio HCCI engine. Due to the high ignition resistance of ammonia, hydrogen was used to promote and stabilize the combustion. Equivalence ratios of 0.2 to 0.3 were utilized to limit the pressure rise rate. Engine speed was kept constant at 1500 rpm at an intake pressure from 1 to 1.5 bar and with intake temperatures from 428 to 473 K.
2017-09-04
Technical Paper
2017-24-0089
S. vedharaj, R vallinayagam, Yanzhao An, Alaaeldin Dawood PhD, Mohammad Izadi Najafabadi, Bart Somers, Junseok Chang, Bengt Johansson
The literature study on PPC in optical engine reveals investigations on OH chemiluminescence and combustion stratification. So far, mostly PRF fuel is studied and it is worthwhile to examine the effect of fuel properties on PPC. Therefore, in this work, fuel having different octane rating and physical properties are selected and PPC is studied in an optical engine. The fuels considered in this study are diesel, heavy naphtha, light naphtha and their corresponding surrogates such as heptane, PRF50 and PRF65 respectively. Without EGR (Intake O2 = 21%), these fuels are tested at an engine speed of 1200 rpm, fuel injection pressure of 800 bar and pressure at TDC = 35 bar. SOI is changed from late to early fuel injection timings to study PPC and the shift in combustion regime from CI to PPC is explored for all fuels. An increased understanding on the effect of fuel octane number, physical properties and chemical composition on combustion and emission formation is obtained.
2017-09-04
Technical Paper
2017-24-0088
Gregory Roberts, Christine Mounaim Rousselle, Mark Musculus, Martin Wissink, Scott Curran, Ethan Eagle
Reactivity Controlled Compression Ignition (RCCI) is an approach to increase engine efficiency and lower engine-out emissions by using in-cylinder stratification of fuels of differing reactivity (i.e., autoignition characteristics) to control combustion phasing. RCCI is defined by an early, high-pressure, direct injection of a high-reactivity fuel into a premixture of low-reactivity fuel and air that yields a significant dwell before start of combustion. The degree of in-cylinder stratification of the two fuels can be altered by varying the injection timing of the high-reactivity fuel, causing transitions between various regimes of combustion. These progress as injection timing is retarded from highly-premixed autoignition to sequential autoignition driven by reactivity stratification (i.e., RCCI) to more diffusion-controlled, diesel-like combustion.
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
2017-24-0090
Robert E. Morgan, Morgan Heikal, Emily Pike-Wilson
Urban air quality remains a major concern, in particular NOx and particle emission from diesel powered vehicles. Electrification offers a medium to long term solution, but there remains a need to significantly reduce internal combustion engine emissions in the short and medium term and potentially in the long term for long range inter city transportation. Late injection low temperature combustion (LTC) has the potential to achieve ultra-low emissions levels in a compression ignition engine by increasing the lean pre-mixed burn fraction. However, significant quantities of diluent are normally required to achieve the required delay in ignition and pre-mixing. This results in high boost requirements and increased pumping work negating the benefit of the LTC combustion strategy and increasing fuel consumption. Test results from a single cylinder light duty research engine are presented using a novel ramped 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
2017-24-0095
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
2017-24-0092
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.
Viewing 61 to 90 of 110083