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R. Lemaire - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Laser-Induced Fluorescence Spectra Obtained in Spray Flames of Diesel and Rapeseed Methyl Ester Using the Multiple-Excitation Wavelength Laser-Induced Incandescence Technique with IR, UV, and Visible Excitations
Combustion Science and Technology, 2015Co-Authors: Salma Bejaoui, R. Lemaire, Eric TherssenAbstract:Laser induced fluorescence (LIF) measurements have been performed in spray flames of diesel and Rapeseed Methyl Ester (RME) using laser excitations of 266 nm, 355 nm, and 532 nm. Ultraviolet (UV) measurements in cold sprays of both fuels have also been carried out and are reported in this article. The LIF spectra obtained when exciting the cold spray of diesel with 266-nm and 355-nm laser excitations have been correlated to the presence of petrogenic polycyclic aromatic hydrocarbons (PAHs), which are known to be present in petroleum-derived fuels. Low fluorescence signals have also been detected for such excitation wavelengths in the RME spray. These signals have been related to the presence of trace species derived from the vegetable oil used to obtain the studied biodiesel. LIF signals obtained in flame conditions have been originally derived using a spectrally resolved multiple-excitation wavelength technique coupling laser-induced incandescence and fluorescence (LII/LIF). Such a technique is well adap...
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Analysis of Laser-Induced Fluorescence Spectra Obtained in Spray Flames of Diesel and Rapeseed Methyl Ester Using the Multiple-Excitation Wavelength Laser-Induced Incandescence Technique with IR, UV, and Visible Excitations
Combustion Science and Technology, 2015Co-Authors: Salma Bejaoui, R. Lemaire, Eric TherssenAbstract:Laser induced fluorescence (LIF) measurements have been performed in spray flames of diesel and Rapeseed Methyl Ester (RME) using laser excitations of 266 nm, 355 nm, and 532 nm. Ultraviolet (UV) measurements in cold sprays of both fuels have also been carried out and are reported in this article. The LIF spectra obtained when exciting the cold spray of diesel with 266-nm and 355-nm laser excitations have been correlated to the presence of petrogenic polycyclic aromatic hydrocarbons (PAHs), which are known to be present in petroleum-derived fuels. Low fluorescence signals have also been detected for such excitation wavelengths in the RME spray. These signals have been related to the presence of trace species derived from the vegetable oil used to obtain the studied biodiesel. LIF signals obtained in flame conditions have been originally derived using a spectrally resolved multiple-excitation wavelength technique coupling laser-induced incandescence and fluorescence (LII/LIF). Such a technique is well adapted to isolate fluorescence emissions with a high signal/noise ratio in flame regions where soot and soot precursors coexist. A significant reduction of the LIF intensities has been observed for the three considered excitation wavelengths when using RME instead of diesel. The spectra obtained as a function of the height above the burner (HAB) with UV excitations are red-shifted in the diesel flame, while they exhibit the same spectral width in the RME one. This could be explained by the presence of other species in the RME flame, such as carbonyl compounds, that can interfere with the fluorescence of PAHs. LIF spectra at 532 nm present the same shape in both flames regardless of the HAB. Similar LIF spectra have also been obtained at specific positions in both flames with UV and visible excitations, which can be related to a similar distribution of PAHs. Thus, such a finding suggests that the heavy aromatic compounds that are related to the formation of nascent soot are similar despite the absence of petrogenic PAHs in RME.
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Study of soot formation during the combustion of Diesel, Rapeseed Methyl Ester and their surrogates in turbulent spray flames
Fuel, 2013Co-Authors: R. Lemaire, S. Bejaoui, Eric TherssenAbstract:Abstract Effects induced by the use of Rapeseed Methyl Ester (RME) as additive or Diesel substitute on the soot formation process have been studied in turbulent spray flames. Investigations have been carried out by coupling Laser-Induced Incandescence and Fluorescence (LII/LIF) at 1064, 532 and 266 nm. LII and LIF profiles obtained with fuels containing various amounts of Ester (from 10 to 100 vol.%) showed that the addition of RME to a European low-sulphur Diesel or to a Diesel surrogate (a n-decane/1-Methylnaphthalene blend derived from the ‘IDEA’ fuel) induces significant reductions of the quantities of soot and soot precursors (including high-number ring aromatic species and light soot precursors). The study of different RME surrogates (n-decane, n-hexadecane, 1-octadecene and Methyl oleate) also revealed that the details of the oxidation of biodiesels could be mimicked only using large Methyl Esters as surrogates. N-alkanes and n-alkenes were found to be unable to reproduce the soot formation process occurring during the combustion of large fatty acid Methyl Esters (FAME) such as those contained in RME. The analysis of the correlation existing between the threshold soot index (TSI) and the peak soot volume fraction measured in flames of m-IDEA/RME blends containing up to 80% of Ester allowed the identification of the different effects involved in the soot reduction (i.e. the dilution and the Ester functional group effects). The estimation of their relative contribution has also been investigated. Finally, the LII fluence curves and time decays obtained at different heights above the burner in flames burning Diesel and a Diesel/RME mixture have been compared. By this way, it has been demonstrated that biodiesel soot are bigger than Diesel ones in the soot formation region. On the other hand, particles oxidize much faster when RME is added to Diesel.
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Examination of wavelength dependent soot optical properties of diesel and diesel/Rapeseed Methyl Ester mixture by extinction spectra analysis and LII measurements
Applied Physics B, 2011Co-Authors: R. Lemaire, E. Therssen, P. Desgroux, A. CoppalleAbstract:The refractive index of soot is an essential parameter for its optical diagnostics. It is necessary for quantitative interpretation of LII (Laser Induced Incandescence) signals, light scattering or extinction measurements as well as for emissivity calculations. The most cited values have been determined by intrusive methods or without taking into account the soot size distribution and its specific morphology. In the present study, soot generated by the combustion of diesel and diesel/Rapeseed Methyl Ester (RME) mixture (70% diesel and 30% RME) are extensively characterized by taking into account the morphology, the aggregate size distribution, the mass fraction and the spectral dispersion of light. The refractive index m for wavelengths λ between 300 and 1000 nm is determined for diesel and diEster fuels by both in-situ and ex-situ methods. The ex-situ method is based on the interpretation of extinction spectra by taking into account soot sizes and fractal morphology with the RDG-FA (Rayleigh–Debye–Gans for Fractal Aggregate) theory. The in-situ approach is based on the comparison of the LII signals obtained with two different excitation wavelengths. The absorption function E ( m ) and the scattering function F ( m ) are examined. This study reveals similar optical properties of soot particles generated by both studied fuels even at ambient and flame temperatures. The function E ( m ) is shown to reach a maximum for λ =250 nm and to tend toward a plateau-like behavior close to E ( m )=0.3 for higher wavelength (600< λ (nm)
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examination of wavelength dependent soot optical properties of diesel and diesel Rapeseed Methyl Ester mixture by extinction spectra analysis and lii measurements
Applied Physics B, 2011Co-Authors: J Yon, R. Lemaire, E. Therssen, P. Desgroux, A. Coppalle, Kuan Fang RenAbstract:The refractive index of soot is an essential parameter for its optical diagnostics. It is necessary for quantitative interpretation of LII (Laser Induced Incandescence) signals, light scattering or extinction measurements as well as for emissivity calculations. The most cited values have been determined by intrusive methods or without taking into account the soot size distribution and its specific morphology. In the present study, soot generated by the combustion of diesel and diesel/Rapeseed Methyl Ester (RME) mixture (70% diesel and 30% RME) are extensively characterized by taking into account the morphology, the aggregate size distribution, the mass fraction and the spectral dispersion of light. The refractive index m for wavelengths λ between 300 and 1000 nm is determined for diesel and diEster fuels by both in-situ and ex-situ methods. The ex-situ method is based on the interpretation of extinction spectra by taking into account soot sizes and fractal morphology with the RDG-FA (Rayleigh–Debye–Gans for Fractal Aggregate) theory. The in-situ approach is based on the comparison of the LII signals obtained with two different excitation wavelengths. The absorption function E(m) and the scattering function F(m) are examined. This study reveals similar optical properties of soot particles generated by both studied fuels even at ambient and flame temperatures. The function E(m) is shown to reach a maximum for λ=250 nm and to tend toward a plateau-like behavior close to E(m)=0.3 for higher wavelength (600<λ (nm)<1000). The function F(m) is found to be quite constant for 400<λ (nm)<1000 and equal to 0.31.
Eric Therssen - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Laser-Induced Fluorescence Spectra Obtained in Spray Flames of Diesel and Rapeseed Methyl Ester Using the Multiple-Excitation Wavelength Laser-Induced Incandescence Technique with IR, UV, and Visible Excitations
Combustion Science and Technology, 2015Co-Authors: Salma Bejaoui, R. Lemaire, Eric TherssenAbstract:Laser induced fluorescence (LIF) measurements have been performed in spray flames of diesel and Rapeseed Methyl Ester (RME) using laser excitations of 266 nm, 355 nm, and 532 nm. Ultraviolet (UV) measurements in cold sprays of both fuels have also been carried out and are reported in this article. The LIF spectra obtained when exciting the cold spray of diesel with 266-nm and 355-nm laser excitations have been correlated to the presence of petrogenic polycyclic aromatic hydrocarbons (PAHs), which are known to be present in petroleum-derived fuels. Low fluorescence signals have also been detected for such excitation wavelengths in the RME spray. These signals have been related to the presence of trace species derived from the vegetable oil used to obtain the studied biodiesel. LIF signals obtained in flame conditions have been originally derived using a spectrally resolved multiple-excitation wavelength technique coupling laser-induced incandescence and fluorescence (LII/LIF). Such a technique is well adap...
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Analysis of Laser-Induced Fluorescence Spectra Obtained in Spray Flames of Diesel and Rapeseed Methyl Ester Using the Multiple-Excitation Wavelength Laser-Induced Incandescence Technique with IR, UV, and Visible Excitations
Combustion Science and Technology, 2015Co-Authors: Salma Bejaoui, R. Lemaire, Eric TherssenAbstract:Laser induced fluorescence (LIF) measurements have been performed in spray flames of diesel and Rapeseed Methyl Ester (RME) using laser excitations of 266 nm, 355 nm, and 532 nm. Ultraviolet (UV) measurements in cold sprays of both fuels have also been carried out and are reported in this article. The LIF spectra obtained when exciting the cold spray of diesel with 266-nm and 355-nm laser excitations have been correlated to the presence of petrogenic polycyclic aromatic hydrocarbons (PAHs), which are known to be present in petroleum-derived fuels. Low fluorescence signals have also been detected for such excitation wavelengths in the RME spray. These signals have been related to the presence of trace species derived from the vegetable oil used to obtain the studied biodiesel. LIF signals obtained in flame conditions have been originally derived using a spectrally resolved multiple-excitation wavelength technique coupling laser-induced incandescence and fluorescence (LII/LIF). Such a technique is well adapted to isolate fluorescence emissions with a high signal/noise ratio in flame regions where soot and soot precursors coexist. A significant reduction of the LIF intensities has been observed for the three considered excitation wavelengths when using RME instead of diesel. The spectra obtained as a function of the height above the burner (HAB) with UV excitations are red-shifted in the diesel flame, while they exhibit the same spectral width in the RME one. This could be explained by the presence of other species in the RME flame, such as carbonyl compounds, that can interfere with the fluorescence of PAHs. LIF spectra at 532 nm present the same shape in both flames regardless of the HAB. Similar LIF spectra have also been obtained at specific positions in both flames with UV and visible excitations, which can be related to a similar distribution of PAHs. Thus, such a finding suggests that the heavy aromatic compounds that are related to the formation of nascent soot are similar despite the absence of petrogenic PAHs in RME.
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Study of soot formation during the combustion of Diesel, Rapeseed Methyl Ester and their surrogates in turbulent spray flames
Fuel, 2013Co-Authors: R. Lemaire, S. Bejaoui, Eric TherssenAbstract:Abstract Effects induced by the use of Rapeseed Methyl Ester (RME) as additive or Diesel substitute on the soot formation process have been studied in turbulent spray flames. Investigations have been carried out by coupling Laser-Induced Incandescence and Fluorescence (LII/LIF) at 1064, 532 and 266 nm. LII and LIF profiles obtained with fuels containing various amounts of Ester (from 10 to 100 vol.%) showed that the addition of RME to a European low-sulphur Diesel or to a Diesel surrogate (a n-decane/1-Methylnaphthalene blend derived from the ‘IDEA’ fuel) induces significant reductions of the quantities of soot and soot precursors (including high-number ring aromatic species and light soot precursors). The study of different RME surrogates (n-decane, n-hexadecane, 1-octadecene and Methyl oleate) also revealed that the details of the oxidation of biodiesels could be mimicked only using large Methyl Esters as surrogates. N-alkanes and n-alkenes were found to be unable to reproduce the soot formation process occurring during the combustion of large fatty acid Methyl Esters (FAME) such as those contained in RME. The analysis of the correlation existing between the threshold soot index (TSI) and the peak soot volume fraction measured in flames of m-IDEA/RME blends containing up to 80% of Ester allowed the identification of the different effects involved in the soot reduction (i.e. the dilution and the Ester functional group effects). The estimation of their relative contribution has also been investigated. Finally, the LII fluence curves and time decays obtained at different heights above the burner in flames burning Diesel and a Diesel/RME mixture have been compared. By this way, it has been demonstrated that biodiesel soot are bigger than Diesel ones in the soot formation region. On the other hand, particles oxidize much faster when RME is added to Diesel.
A Tsolakis - One of the best experts on this subject based on the ideXlab platform.
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characteristics of lpg diesel dual fuelled engine operated with Rapeseed Methyl Ester and gas to liquid diesel fuels
Energy, 2012Co-Authors: Hendry S Tira, A Tsolakis, Jose Martin Herreros, Miroslaw L. WyszynskiAbstract:A Liquefied Petroleum Gas (LPG)-diesel dual fuelled combustion experimental study was carried out to understand the impact of the properties of the direct injection diesel fuels, such as Rapeseed Methyl Ester (RME) and gas-to-liquid (GTL), on combustion characteristics, engine performance and emissions. The experimental results showed that up to 60% of liquid fuel replacement by LPG was reached while keeping engine combustion variability within the acceptable range and obtaining clear benefits in the soot-NOx trade-off. However, the amount of LPG was limited by adverse effects in engine thermal efficiency, HC and CO emissions. LPG–RME showed a good alternative to LPG-diesel dual fuelling, as better engine combustion variability, HC, CO and soot behaviour was obtained when compared to the other liquid fuels, mainly due to its fuel oxygen content. On the other hand, NOx emissions were the highest, but these can be balanced by the application of EGR. LPG–GTL dual fuelling resulted in the highest NOx emissions benefit over a wide range of engine operating conditions. The high cetane number and the absence of aromatic of GTL are the main parameters for the more favourable soot-NOx trade-off compared to LPG–ULSD (ultra low sulphur diesel) dual fuelling.
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Corrosion effects of RME in blends with ULSD on aluminium and copper
Fuel Processing Technology, 2012Co-Authors: Shahrouz Norouzi, Farshad Eslami, Miroslaw L. Wyszynski, A TsolakisAbstract:Abstract The present study concerns corrosion of aluminium and copper in ultra low sulphur diesel fuel and its blends with Rapeseed Methyl Ester. Tests were carried out at wide ranging contents of Rapeseed Methyl Ester (0%, 50%, 75% and 100%) at 80 °C for 600 h. At the end of the immersion test a comparison was performed by weight loss corrosion rate measurement and by analysis of damages of metal surfaces. Analysis of fuels was performed by using total acid number measurement and by gas chromatography–mass spectrometry to investigate the acid concentration and change of fuel composition respectively. Damages afflicted on metal surfaces were examined by scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDS). Results showed that increasing the biodiesel content enhanced the corrosiveness of blend to both metals; this was confirmed by analyses of fuel properties and damage on metal surfaces exposed to fuels. Also it was found that copper was more vulnerable to attack compared with aluminium for all blends.
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Investigation of the Deactivation of a NOx-Reducing Hydrocarbon-Selective Catalytic Reduction (HC-SCR) Catalyst by Thermogravimetric Analysis: Effect of the Fuel and Prototype Catalyst
Energy & Fuels, 2010Co-Authors: José Rodríguez-fernández, A Tsolakis, M. Ahmadinejad, S. SitsheboAbstract:Diesel engines, fuels, and aftertreatment systems have to be optimized together to meet the targets imposed in the engine and vehicle emissions regulations, especially for particulate matter (PM) and nitrogen oxides (NOx). Hydrocarbon-selective catalytic reduction (HC-SCR) over Ag/Al2O3 catalysts is an attractive, cost-effective choice for reducing NOx, especially in the presence of hydrogen, which can be produced on-board in a fuel reformer. However, at low temperatures, the Ag/Al2O3-SCR catalyst activity decays rapidly, indicating a time period of activity loss. In this work, the catalyst deactivation process has been studied using a thermogravimetric analyzer (TGA). The effect of the space velocity, hydrogen addition, and the engine exhaust from the engine operation on gas-to-liquid (GTL), Rapeseed Methyl Ester (RME), and ultra-low sulfur diesel (ULSD) fuels at different operating modes was investigated. In addition, the presence of a prototype oxidation catalyst located in-between the engine out and t...
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application of exhaust gas fuel reforming in diesel and homogeneous charge compression ignition hcci engines fuelled with biofuels
Energy, 2008Co-Authors: A Tsolakis, A MegaritisAbstract:This paper documents the application of exhaust gas fuel reforming of two alternative fuels, biodiesel and bioethanol, in internal combustion engines. The exhaust gas fuel reforming process is a method of on-board production of hydrogen-rich gas by catalytic reaction of fuel and engine exhaust gas. The benefits of exhaust gas fuel reforming have been demonstrated by adding simulated reformed gas to a diesel engine fuelled by a mixture of 50% ultra low sulphur diesel (ULSD) and 50% Rapeseed Methyl Ester (RME) as well as to a homogeneous charge compression ignition (HCCI) engine fuelled by bioethanol. In the case of the biodiesel fuelled engine, a reduction of NOx emissions was achieved without considerable smoke increase. In the case of the bioethanol fuelled HCCI engine, the engine tolerance to exhaust gas recirculation (EGR) was extended and hence the typically high pressure rise rates of HCCI engines, associated with intense combustion noise, were reduced.
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engine performance and emissions of a diesel engine operating on diesel rme Rapeseed Methyl Ester blends with egr exhaust gas recirculation
Energy, 2007Co-Authors: A Tsolakis, A Megaritis, Miroslaw L. Wyszynski, K. TheinnoiAbstract:The effects of biodiesel (Rapeseed Methyl Ester, RME) and different diesel/RME blends on the diesel engine NOx emissions, smoke, fuel consumption, engine efficiency, cylinder pressure and net heat release rate are analysed and presented. The combustion of RME as pure fuel or blended with diesel in an unmodified engine results in advanced combustion, reduced ignition delay and increased heat release rate in the initial uncontrolled premixed combustion phase. The increased in-cylinder pressure and temperature lead to increased NOx emissions while the more advanced combustion assists in the reduction of smoke compared to pure diesel combustion. The lower calorific value of RME results in increased fuel consumption but the engine thermal efficiency is not affected significantly. When similar percentages (% by volume) of exhaust gas recirculation (EGR) are used in the cases of diesel and RME, NOx emissions are reduced to similar values, but the smoke emissions are significantly lower in the case of RME. The retardation of the injection timing in the case of pure RME and 50/50 (by volume) blend with diesel results in further reduction of NOx at a cost of small increases of smoke and fuel consumption.
Theodosios Korakianitis - One of the best experts on this subject based on the ideXlab platform.
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Experimentally tested performance and emissions advantages of using natural-gas and hydrogen fuel mixture with diesel and Rapeseed Methyl Ester as pilot fuels
Applied Energy, 2018Co-Authors: S. Imran, Theodosios Korakianitis, Rabia Shaukat, Muhammad Farooq, Sridhar S. Condoor, S. JayaramAbstract:Abstract Higher unburned hydrocarbon emissions are attributed to the relatively low temperature combustion of natural gas in compression ignition engines whereas the combustion of hydrogen in compression ignition environment results in higher NOX. These emissions characteristics are explained on the basis of different physio-chemical properties of the two gaseous fuel: higher Cp value in case of natural gas and higher diffusion coefficient, wider flammability limits and shorter quenching gaps for hydrogen are held responsible for these trends. This study assesses the potential of hydrogen being used in combination with natural gas with diesel and Rapeseed Methyl Ester (RME) as pilot fuels. This type of fueling can be referred as ‘triple fueling of the compression ignition engines’ and has the potential to achieve a better trade-off between the higher NOX associated with hydrogen and higher hydrocarbon emissions associated with natural gas based dual fueling of compression ignition engines. The present study has investigated the potential of the triple fueling of the compression ignition engines so far the attainment of a better trade-off between NOX and hydrocarbon emissions are concerned. Comparing the specific NOX and hydrocarbon emissions in different cases reveals that a significant drop in specific hydrocarbon emissions can be achieved at the cost of a small increment in specific NOX. At both speeds (1000 rev/min and 1500 rev/min), the reduction in hydrocarbon emissions is more prominent at relatively lower loads, which can be a potential solution of reducing specific hydrocarbon emissions at lower loads in diesel engine operations. The stoichiometric equation for the triple fueling (Diesel or RME piloted mixture of natural gas and hydrogen) is also presented.
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Performance and specific emissions contours throughout the operating range of hydrogen-fueled compression ignition engine with diesel and RME pilot fuels
Alexandria Engineering Journal, 2015Co-Authors: Shahid Imran, David R. Emberson, Amjad Hussain, Hassan Ali, Balazs Ihracska, Theodosios KorakianitisAbstract:This paper presents the performance and emissions contours of a hydrogen dual fueled compression ignition (CI) engine with two pilot fuels (diesel and Rapeseed Methyl Ester), and com- pares the performance and emissions iso-contours of diesel and Rapeseed Methyl Ester (RME) single fueling with diesel and RME piloted hydrogen dual fueling throughout the engines operating speed and power range. The collected data have been used to produce iso-contours of thermal efficiency, volumetric efficiency, specific oxides of nitrogen (NOX), specific hydrocarbons (HC) and specific carbon dioxide (CO2) on a power-speed plane. The performance and emission maps are experimen- tally investigated, compared, and critically discussed. Apart from medium loads at lower and med- ium speeds with diesel piloted hydrogen combustion, dual fueling produced lower thermal efficiency everywhere across the map. For diesel and RME single fueling the maximum specific NOX emis- sions are centered at the mid speed, mid power region. Hydrogen dual fueling produced higher specific NOX with both pilot fuels as compared to their respective single fueling operations. The range, location and trends of specific NOX varied significantly when compared to single fueling
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diesel and Rapeseed Methyl Ester rme pilot fuels for hydrogen and natural gas dual fuel combustion in compression ignition engines
Fuel, 2011Co-Authors: Theodosios Korakianitis, A.m. Namasivayam, R.j. CrookesAbstract:This paper presents experimental results of Rapeseed Methyl Ester (RME) and diesel fuel used separately as pilot fuels for dual-fuel compression–ignition (CI) engine operation with hydrogen gas and natural gas (the two gaseous fuels are tested separately). During hydrogen dual-fuel operation with both pilot fuels, thermal efficiencies are generally maintained. Hydrogen dual-fuel CI engine operation with both pilot fuels increases NOx emissions, while smoke, unburnt HC and CO levels remain relatively unchanged compared with normal CI engine operation. During hydrogen dual-fuel operation with both pilot fuels, high flame propagation speeds in addition to slightly increased ignition delay result in higher pressure-rise rates, increased emissions of NOx and peak pressure values compared with normal CI engine operation. During natural gas dual-fuel operation with both pilot fuels, comparatively higher unburnt HC and CO emissions are recorded compared with normal CI engine operation at low and intermediate engine loads which are due to lower combustion efficiencies and correspond to lower thermal efficiencies. This could be due to the pilot fuel failing to ignite the natural gas–air charge on a significant scale. During dual-fuel operation with both gaseous fuels, an increased overall hydrogen–carbon ratio lowers CO2 emissions compared with normal engine operation. Power output (in terms of brake mean effective pressure, BMEP) as well as maximum engine speed achieved are also limited. This results from a reduced gaseous fuel induction capability in the intake manifold, in addition to engine stability issues (i.e. abnormal combustion). During all engine operating modes, diesel pilot fuel and RME pilot fuel performed closely in terms of exhaust emissions. Overall, CI engines can operate in the dual-fuel mode reasonably successfully with minimal modifications. However, increased NOx emissions (with hydrogen use) and incomplete combustion at low and intermediate loads (with natural gas use) are concerns; while port gaseous fuel induction limits power output at high speeds.
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Assessment of combustion in natural gas dual-fuelled compression ignition engines with diMethyl ether and Rapeseed Methyl Ester pilot ignition
International Journal of Engine Research, 2009Co-Authors: A.m. Namasivayam, R.j. Crookes, Theodosios Korakianitis, John OlsenAbstract:Compression-ignition engines are known to be more efficient than similar-sized spark-ignition engines because of the higher compression ratios and leaner combustion. The emissions of soot and nitrogen oxides remain the main hurdle in the complete exploitation of these engines. Dual-fuelling is one means favoured for solving the emission problem, in which high-octane fuels are used as the main fuel which is ignited by a smaller pilot injection of diesel or another high-cetane fuel. These dual-fuel engines produceless particulate matter and nitrogen oxides than spark-ignition engines, while retaining the desired compression-ignition engine efficiency. In thepresent investigation, tests were conducted using a variety of renewable and non-renewable fuels for pilot injection. The pilot fuels employed wereconventional diesel, Rapeseed Methyl Ester (known as biodiesel), and diMethyl ether, while natural gas was used as the main fuel. Biogas, or landfill gas, would be the renewable alternative. Pressure versus crank angle traces were obtained, together with their first and second derivatives. These were analysed to determine the crank angle at which ignition began. Diagrams that show the rate of reaction were also plotted for the same purpose. Here, the start of ignition is determined by the trace suddenly changingslope and rising above zero. Using these methods, the ignition delay was determined for different operating conditions and comparisons drawn for different pilot fuels. The characteristic shapes of rate-of-reaction curves were analysed highlighting differences in the combustion processes occurring in single- and dual-fuel diesel engine operation. Emissions data for different operating conditions were also obtained and analysed, showing a tendency for lower emissions of smoke and oxides of nitrogen but increased carbon monoxide and unburnt hydrocarbons to be produced in dual-fuelling. Carbon dioxide was also reduced
Bianca Maria Vaglieco - One of the best experts on this subject based on the ideXlab platform.
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Analysis of combustion phenomena and pollutant formation in a small compression ignition engine fuelled with blended and pure Rapeseed Methyl Ester
Energy, 2016Co-Authors: Agnese Magno, Ezio Mancaruso, Bianca Maria VagliecoAbstract:This paper deals with an investigation on the combustion process and pollutant formation of a small diesel engine fuelled with blended and pure biodiesel. The engine is a three-cylinder, 1028 cc, equipped with a common rail injection system. Endoscope based optical setup was used to observe in the cylinder without significant interference to the combustion process. Combustion images were post-processed by two-colour pyrometry method to evaluate the flame temperature and the in-cylinder soot concentration. Optical data were correlated to the nitrogen oxides and the particulate matter emissions measured at exhaust. Experiments were carried out at different operating conditions. It was found out that without EGR (exhaust gas recirculation), blended and pure RME (Rapeseed Methyl Ester) were characterized by higher flame temperature and also by higher NOx emissions. In presence of EGR, lower flame temperature was detected for biodiesel; in this case higher NOx emissions were measured with biodiesel but the difference with NOx emissions from diesel fuel were reduced. Moreover, blended and pure biodiesel combustion was characterized by lower in-cylinder soot formation and also lower PM (particulate matters) at exhaust.
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Evaluation of RME (Rapeseed Methyl Ester) and mineral diesel fuels behaviour in quiescent vessel and EURO 5 engine.
Energy, 2014Co-Authors: Luigi Allocca, Ezio Mancaruso, Luigi Sequino, Alessandro Montanaro, Bianca Maria VagliecoAbstract:Alternative diesel fuels for internal combustion engines have grown significantly in interest in the last decade. This is due to the potential benefits in pollutant emissions and particulate matter reduction. Nevertheless at possible increase in nitrogen oxide (NOx), and almost certainly increase of fuel consumption have been observed.
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GTL (Gas To Liquid) and RME (Rapeseed Methyl Ester) combustion analysis in a transparent CI (compression ignition) engine by means of IR (infrared) digital imaging
Energy, 2013Co-Authors: Ezio Mancaruso, Luigi Sequino, Bianca Maria VagliecoAbstract:In the present paper, (infrared) IR measurements were performed in order to study the behaviour of biofuels combustion in a transparent Euro 5 diesel engine operating in premixed mode. (Commercial diesel fuel) REF, (Gas To Liquid) GTL and (Rapeseed Methyl Ester) RME biofuels have been used. An elongated single-cylinder transparent engine equipped with the multi-cylinder head of commercial passenger car and (common rail) CR injection system was used. A sapphire window was set in the bottom of the combustion chamber, and a sapphire ring was placed in the upper part of the cylinder. Measurements were carried out through both accesses by means of high-speed infrared digital imaging system. IR camera was able to detect the emitted light in the wavelength range 1.5–5 μm. Infrared imaging allowed acquiring larger amount of information than UV (ultraviolet) and visible cameras. In particular the IR camera was used for the characterization of injection and combustion process. Analysing the IR images, it was possible to identify clearly the seven jets of vaporized fuel that react with air in the bowl. During the late combustion phase, the IR image showed a good capability to follow the hot burned gas both in the bowl and above the piston. The IR camera has shown high sensibility permitting to follow carefully the soot oxidation process within the cylinder. The GTL shows an advance of about 8° crank angles in the evolution of combustion process with respect to the RME. On the contrary a longer chemical activity has been detected for the latter biofuel. Finally, the IR camera was revealed very useful tool to characterize the combustion process for long time allowing high quality of the results. Images of the reactions that happen in the combustion chamber and above the piston head were clearly acquired even if the optical windows were obscured by the soot produced from the previous combustion cycles.
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An experimental comparison of n-Heptane, RME and diesel fuel on combustion characteristics in a compression ignition engine
Fuel Processing Technology, 2013Co-Authors: Ezio Mancaruso, Bianca Maria VagliecoAbstract:Abstract A two dimensional visualization of premixed combustion process was performed in a common rail (CR) Euro 5 optically accessible compression ignition engine. The effect of fuel properties on injection and combustion phenomena was evaluated by using commercial diesel fuel, as reference, Rapeseed Methyl Ester (RME), and a paraffinic fuel, such as n-Heptane. The choice of monocomponent fuels, free of aromatic, allowed the analysis of the contribution to soot formation with respect to European diesel fuel. Evaluation of the soot volumetric fraction was made for all the fuels. The first soot occurs at the same location for the analyzed fuels but at different times. n-Heptane was the fuel which gave the lowest soot production in accordance with its better physical and chemical characteristics. The total amount of soot formed during the combustion of RME resulted to be intermediate between n-Heptane and diesel fuel.