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Viewing 1 to 30 of 16480
2017-09-04
Technical Paper
2017-24-0027
Nearchos Stylianidis, Ulugbek Azimov, Nobuyuki Kawahara, Eiji Tomita
A chemical kinetics and computational fluid-dynamics (CFD) analysis were performed to evaluate the combustion of syngas derived from biomass and coke-oven solid feedstock in a micro-pilot ignited supercharged dual-fuel engine under lean conditions. For this analysis, a new reduced syngas chemical kinetics mechanism was constructed and validated by comparing the ignition delay and laminar flame speed data with those obtained from experiments and other detail chemical kinetics analysis available in the literature. The reaction sensitivity analysis was conducted for ignition delay at elevated pressures in order to identify important chemical reactions that govern the combustion process. We found that HO2+OH=H2O+O2 and H2O2+H=H2+HO2 reactions showed very high sensitivity during high-pressure ignition delay times and had considerable uncertainty.
2017-09-04
Technical Paper
2017-24-0034
Michele Battistoni, Carlo N. Grimaldi, Valentino Cruccolini, Gabriele Discepoli, Matteo De Cesare
Water injection in highly boosted GDI engines has become an attractive area over the last few years as a way of increasing efficiency, enhancing performance and reducing emissions. The technology and its effects are not new, but current gasoline engine trends for passenger vehicles have several motivations for adopting this technology today. Water injection enables higher compression ratios, optimal spark timing and elimination of fuel enrichment at high load, and possibly replacement of EGR. Physically, water reduces charge temperature by evaporation, dilutes combustion, and varies the specific heat ratio of the working fluid, with complex effects. Several of these mutually intertwined aspects are investigated in this paper through CFD simulations, focusing on a turbo-charged GDI engine with port water injection. Different strategies for water injection timing, pressure and spray targeting are investigated.
2017-09-04
Technical Paper
2017-24-0060
Nicolo Cavina, Nahuel Rojo, Lorella Ceschini, Eleonora Balducci, Luca Poggio, Lucio Calogero, Ruggero Cevolani
The recent search for extremely efficient spark-ignition engines has implied a great increase of in-cylinder pressure and temperature levels, and knocking combustion mode has become one of the most relevant limiting factors. This paper reports the main results of a specific project carried out as part of a wider research activity, aimed at modelling and real-time controlling knock-induced damage on aluminium forged pistons. The paper shows how the main damage mechanisms (erosion, plastic deformation, surface roughness, hardness reduction) have been identified and isolated, and how the corresponding symptoms may be measured and quantified. The second part of the work then concentrates on understanding how knocking combustion characteristics affect the level of damage done, and which parameters are mainly responsible for piston failure.
2017-09-04
Technical Paper
2017-24-0026
Davide Paredi, Tommaso Lucchini, Gianluca D'Errico, Angelo Onorati, Stefano Golini, Nicola Rapetto
The scope of the work presented in this paper was to apply the latest open source CFD achievements to design a state of art, direct-injection (DI), heavy-duty, natural gas-fueled engine. Within this context, an initial steady-state analysis of the in-cylinder flow was performed by simulating three different intake ducts geometries, each one with seven different valve lift values, chosen according to an estabilished methodology proposed by AVL. The discharge coefficient (Cd) and the Tumble Ratio (TR) were calculated in each case, and an optimal intake ports geometry configuration was assessed in terms of a compromise between the desired intensity of tumble in the chamber and the satisfaction of an adequate value of Cd. Subsequently, full-cycle, cold-flow simulations were performed for three different engine operating points, in order to evaluate the in-cylinder development of TR and turbulent kinetic energy (TKE) under transient conditions.
2017-09-04
Technical Paper
2017-24-0039
Daniele Piazzullo, Michela Costa, Youngchul Ra, Vittorio ROCCO, Ankith Ullal
Bio-derived fuels are drawing more and more attention in the internal combustion engine (ICE) research field in recent years. Those interests in use of renewable biofuels in ICE applications derive from energy security issues and, more importantly, from environment pollutant emissions concerns. High fidelity numerical study of engine combustion requires advanced computational fluid dynamics (CFD) to be coupled with detailed chemical kinetic models. This task becomes extremely challenging if real fuels are taken into account, as they include a mixture of hundreds of different hydrocarbons, which prohibitively increases computational cost. Therefore, along with employing surrogate fuel models, reduction of detailed kinetic models for multidimensional engine applications is preferred. In the present work, a reduced mechanism was developed for primary reference fuel (PRF) using the directed relation graph (DRG) approach. The mechanism was generated from an existing detailed mechanism.
2017-09-04
Technical Paper
2017-24-0059
Massimo FERRERA
The 2020+ CO2 and noxious emission limits will impose drastic technological choices. Even though in 2030 65% of road transportation vehicles will be still powered by an Internal Combustion Engine, a progressive increase of hybrids and battery electric vehicles will be confirmed. In parallel, the use of Low-Carbon Alternative Fuels, such as Natural Gas/Biomethane, will play a fundamental role in accelerating the process of de-carbonisation of the transportation sector supporting the virtuous Circular Economy. Since the nineties FCA invested in Compressed Natural Gas (CNG) powered vehicles becoming Market leader with one of the largest related product portfolios in Europe. A progressive improvement of this technology has been always pursued but, facing the next decades, a further improvement of the current CNG powertrain technology is mandatory to achieve even higher efficiency and remove residual gaps versus conventional fuels.
2017-09-04
Technical Paper
2017-24-0077
Matteo Pelucchi, Mattia Bissoli, Cristina Rizzo, Yingjia Zhang PhD, Kieran Somers PhD, Alessio Frassoldati, Henry Curran, Tiziano Faravelli
Pursuing a sustainable energy scenario for transportation requires the blending of renewable oxygenated fuels such as alcohols into commercial hydrocarbon fuels. From a chemical kinetic perspective, this requires the accurate description of both hydrocarbon reference fuels (n-heptane, iso-octane, toluene, etc.) and oxygenated fuels chemistry. A recent systematic investigation of linear C2–C5 alcohols ignition in a rapid compression machine at p = 10–30 bar and T = 650–900 K has extended the scarcity of fundamental data at such conditions allowing for a revision low temperature chemistry for alcohol fuels in the POLIMI mechanism. Heavier alcohols such as n-butanol and n-pentanol present ignition characteristic of interest for application in HCCI engines, due to the presence of the hydroxyl moiety reducing their low temperature reactivity compared to the parent linear alkanes (i.e. higher octane number).
2017-09-04
Technical Paper
2017-24-0080
Ross Ryskamp, Gregory Thompson, Daniel Carder, John Nuszkowski
Reactivity controlled compression ignition (RCCI) is a form of dual-fuel combustion that exploits the reactivity difference between two fuels to control combustion phasing. This combustion approach limits the formation of oxides of nitrogen (NOX) and soot while retaining high thermal efficiency. The research presented herein was performed to determine the influences that high reactivity (diesel) fuel properties have on RCCI combustion characteristics, exhaust emissions, fuel efficiency, and the operable load range. A 4-cylinder, 1.9 liter, light-duty CI engine was converted to run on diesel fuel (high reactivity fuel) and compressed natural gas (CNG) (low reactivity fuel). The engine was operated at 2100 revolutions per minute (RPM), and at two different loads, 3.6 bar brake mean effective pressure (BMEP) and 6 bar BMEP.
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
2017-24-0086
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
2017-24-0085
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
2017-24-0091
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
2017-24-0089
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
2017-24-0092
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
2017-24-0093
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
2017-24-0055
Enrico Corti, Claudio Forte, Gian Marco Bianchi, Lorenzo Zoffoli
The performance optimization of modern Spark Ignition engines is limited by knock occurrence: heavily downsized engines often are forced to work in the Knock-Limited Spark Advance (KLSA) range. Knock control systems monitor the combustion process, allowing to achieve a proper compromise between performance and reliability. Combustion monitoring is usually carried out by means of accelerometers or ion sensing systems, but recently the use of cylinder pressure sensors is also becoming established, especially for motorsport applications. The cylinder pressure signal is often available in a calibration environment, where SA feedback control is used to avoid damages to the engine during automatic calibration.
2017-09-04
Technical Paper
2017-24-0065
Dr. Helmut Ruhland, Thomas Lorenz, Jens Dunstheimer, Albert Breuer, Maziar Khosravi
An integral part of combustion system development for previous NA gasoline engines was the optimization of charge motion towards the best compromise in terms of full load performance, part load stability, emissions and, last but not least, fuel economy. This situation might have changed with the introduction of GTDI engines. While it is generally accepted that an increased charge motion level improves the mixture preparation of a direct injection gasoline engine, the tradeoff in terms of performance seems to become less dominant as the boosting systems of modern engines are typically sound enough to compensate the flow losses generated by the more restrictive ports. Certainly the increased boost level does not come for free. Increased charge motion generates higher pumping- and wall heat losses. Hence it is questionable and engine dependent, whether more charge motion is always better.
2017-09-04
Technical Paper
2017-24-0069
Hyunwook Park, Jugon Shin, Choongsik Bae
Spray and combustion characteristics of diesel fuel were investigated in order to get a better understanding of the evaporation and combustion behavior under simulated cold-start conditions of a diesel engine. The experiment was conducted in a constant volume combustion chamber and the target ambient conditions were selected as the engine cranking. Mie scattering and shadowgraph techniques were conducted to visualize the liquid and vapor phase of the fuel under non-combustion condition (O2 concentration=0%). In-chamber pressure and direct flame visualization were acquired for spray combustion condition (O2 concentration=21%). The fuel was injected with an injection pressure of 30MPa, which is a typical value during cranking period. The liquid penetration of the fuel was increased at 573K of ambient temperature compared to that at 663K due to the poor evaporation characteristic and the increased fuel viscosity from the lower fuel temperature.
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
2017-24-0096
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
2017-24-0098
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
2017-24-0114
Michel Cuijpers, Michael Golombok, Hylke Van Avendonk, Michael Boot
Recently imposed sulfur caps on shipping fuels in so-called sulfur emission control areas (SECA) are forcing shipping companies to sail on more or less automotive grade diesel in lieu of the considerably less expensive but sulfur-laden heavy fuel oil (HFO). This development is an opportunity for a bio-based substitute, given that most biomass is sulfur free by default. Cracking biomass to an HFO substitute will require both lower capital and operational expenditures - currently less viscous automotive grade fuels are the targeted product. Lower production costs should translate directly into higher profits for biorefineries. We demonstrate the principle of producing a bio-based low sulfur HFO (LSHFO) by cracking lignin - a residual phenolic polymer from cellulosic bioethanol production – with a novel subcritical solvolysis reaction in a mixture of water and ethylene glycol monobutyl ether or EGBE.
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
2017-24-0152
Mirko Baratta, Daniela Misul, Jiajie Xu, Alois Fuerhapter, Rene Heindl, Cesare Peletto, Jean Preuhs, Patrick Salemi
The present paper is the outcome of the research activity carried out by Centro Ricerche Fiat, Politecnico di Torino, Delphi and AVL within the Gason research project of the EC (H2020 program). The overall goal of the research project is to develop CNG-only SI engines which are able to comply with post-EuroVI emission regulations and 2020+ CO2 emission targets, with reference to the new homologation cycle and real driving conditions. The work presented in this paper aimed at developing a small displacement turbocharged engine, which combines the advanced VVA MultiAir system for the air metering with the direct injection of natural gas. The activity focused on the development and fluid-dynamic characterization of the gaseous-fuel injector. Moreover, the combined use of CFD analysis and optical-access PLIF experimental techniques allowed the design of the combustion chamber to be optimized from the mixture formation point of view.
2017-09-04
Technical Paper
2017-24-0143
Sathaporn Chuepeng, Kampanart Theinnoi, Manida Tongroon
The combustion in reactivity controlled compression ignition (RCCI) mode of diesel engine have been gained more attention as one among other strategies to increase operating range for premixed combustion and to improve fuel economy. A low reactivity fuel such as high octane number fuel, alcohol blends for example, is early fumigated (or injected) and premixed with air prior to induction to the combustion chamber. Later on adjacent to the end of the compression stroke, the diesel fuel as a high reactivity fuel is directly injected into the homogeneous pre-mixture and ignited. This can also promote lower nitrogen oxides and particulate matter emissions. The main aim of this work is to characterize the combustion phenomena and particulate matter in nano-size from the RCCI engine using neat hydrous ethanol as the low reactivity fuel.
2017-09-04
Technical Paper
2017-24-0081
Luigi De Simio, Michele Gambino, Sabato Iannaccone
In recent years the use of alternative fuels for internal combustion engines has had a strong push coming from both technical and economic-environmental aspects. Among these, gaseous fuels such as liquefied petroleum gas and natural gas have occupied a segment no longer negligible in the automotive industry, thanks to their adaptability, anti-knock capacity, lower toxicity of pollutants, reduced CO2 emissions and cost effectiveness. On the other hand, diesel engines still represent the reference category among the internal combustion engines in terms of consumptions. The possibility offered by the dual fuel (DF) systems, to combine the efficiency and performance of a diesel engine with the advantages offered by the gaseous fuels, has been long investigated. However the simple replacement of diesel fuel with natural gas does not allow to optimize the performance of the engine due to the high THC emissions particularly at lower loads.
2017-09-04
Technical Paper
2017-24-0169
Robert E. Morgan, Neville Jackson, Andrew Atkins, Guangyu dong, Morgan Heikal, Christopher lenartowicz
Electrification of long haul freight applications offers a number of major challenges mainly the cost and weight of on-board energy storage. Efforts to reduce the cost and complexity of electrification will continue, but there will remain a long term need for a clean and efficient chemically fuelled thermal powertrain. Best in class Otto and Diesel cycles engines are now approaching the practical limits of efficiency, requiring new approaches to deliver future improvements. Harnessing waste heat through a bottoming cycle delivers limited benefit due to the narrow temperature range at which heat is recovered and rejected. Integration of heat recovery directly to the main power cycle, via a ‘split engine cycle’ offers a novel approach to achieving significant improvements in efficiency. In the split engine cycle, compression and combustion strokes are performed in separate chambers.
Viewing 1 to 30 of 16480