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| 2. |
- Csontos, Botond
(författare)
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Analysis of the Interaction between Soft Particles and Fuel Filter Media
- 2021
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- The transportation industry is currently in a transition toward the use of zero-emission vehicles;however, reaching it will take a considerable amount of time. In the meantime, a diesel powertrainwill remain the workhorse for most heavy-duty transportation. In order to reduce the engine’senvironmental impact, biofuels, such as biodiesel, are used as drop-in fuels or fuel blends. The useof drop-in fuels may create challenges for the fuel system since sticky deposits can precipitate andcause injector malfunctioning or premature fuel filter plugging. It has been concluded in the pastthat these deposits have been caused by soft particles. In this article, soft particles created throughthe degradation of biodiesel and their effect on filters are studied. The article aims to analyze fuelfilters and investigate the materials responsible for soft particle separation. The study includes threepre filters and three main filters that are commercially available truck filters. Different membranetypes and membranes with different pore sizes were tested in order to comprehend their potentialfor fuel filtration. The tests were conducted using a custom-built fuel filter rig, where pressure buildupwas measured online. The removal efficiency was assessed by gas chromatography-mass spectrometry(GC-MS) and inductively coupled plasma (ICP). The materials of the filters were examined byFourier-transform infrared spectroscopy (FTIR), scanning electron microscopy/energy-dispersiveX-ray spectroscopy (SEM/EDX), and thermogravimetric analysis (TGA). The analysis revealed novelresults from the interaction of soft particles and different filter media. The filters show similarperformance for the commercial fuel filters with respect to soft particle removal and pressure buildupand thus the tendency for fuel filter plugging, where the efficiency for total calcium ion removal wasaround 40% for pre-filters and 60% for main filters. The material analysis shows that the particlesare most likely removed mainly by the cellulose layer of the filter paper, and filters with glass fibershowed higher capacity. In addition, the membrane filters prove to show good potential for softparticle removal, with the highest removal of 72%; however, their use in practice needs to be furtherevaluated in actual fuel systems.
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| 3. |
- Du, Chengjun, 1985, et al.
(författare)
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Effects of Nozzle Geometry on the Characteristics of an Evaporating Diesel Spray
- 2016
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 9:3, s. 21-
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Tidskriftsartikel (refereegranskat)abstract
- The effects of nozzle geometry on diesel spray characteristics were studied in a spray chamber under evaporating conditions using three single-hole nozzles, one cylindrical and two convergent, designated N1 (outlet diameter 140 μm, k-factor 0), N2 (outlet diameter140 μm, k-factor 2) and N3 (outlet diameter 136 μm, k-factor 2). Spray experiments were performed with each nozzle at two constant gas densities (15 and 30 kg/m3) and an ambient temperature (673 K) at which evaporation occurs, with injection pressures ranging from 800 to 1600 bar. A light absorption and scattering method using visible and UV light was implemented, and shadow images of liquid and vapor phase fuel were recorded with high-speed video cameras. The cylindrical nozzle N1 yielded larger local vapor cone angles than the convergent nozzles N2 and N3 at both gas densities, and the difference became larger as the injection pressureincreased. The vapor phase penetration values for nozzle N1 and N3 were quite similar and always lower than those for N2. This is consistent with the impingement measurements, which showed that the momentum flux of nozzle N1 was only slightly greater than that of nozzle N3, while that of nozzle N2 was substantially greater. The vapor volume fractions measured along the spray’s center line were well explained by the one-dimensional transient diesel jet model, indicating that diesel spray vaporization is controlled by turbulent fuel-air mixing.
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| 4. |
- Du, Chengjun, 1985, et al.
(författare)
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The Influence of Ethanol Blending in Diesel fuel on the Spray and Spray Combustion Characteristics
- 2014
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 7(3):November 2014, s. 823-832
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Tidskriftsartikel (refereegranskat)abstract
- The influence of ethanol blending in Diesel fuel on the spray and spray combustion characteristics was investigated by performing experiments in an optically accessible high-pressure / high-temperature spray chamber under non-evaporating, evaporating and combusting conditions. Three fuels were investigated: (1) Diesel - a European Diesel based on the EN590 standard; (2) E10 - a blend of Diesel containing 10% ethanol and 2% emulsion additive; and (3) E20 - a blend of Diesel containing 20% ethanol and 2% emulsion additive. A constant gas density of 24.3 kg/m3 was maintained under non-evaporating (30 °C, 21.1 bar), evaporating (350 °C, 43.4 bar), low combustion temperature (550 °C, 57.3 bar) and high combustion temperature (600 °C, 60 bar) conditions. A single-hole injector with a nozzle diameter of 0.14 mm was used and injection pressure was held constant at 1350 bar. Various optical methods were used to characterize the non-combusting and combusting sprays.Despite the differences in the fuels' compositions, they did not differ significantly with respect to their liquid phase spray penetrations or cone angles under non-evaporating or evaporating conditions. However, under combusting conditions, reducing the ambient temperature increased the ignition delay and delayed the onset of soot formation for all fuels. Under equivalent combustion conditions, E10 and E20 had longer ignition and soot formation delays than Diesel. As the ethanol content of the fuel was increased from 0% to 20%, the lift-off length increased and the detectable soot luminescence decreased.
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| 5. |
- Hemdal, Stina, 1974, et al.
(författare)
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Stratified cold start sprays of gasoline-ethanol blends
- 2009
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 2:1, s. 683-696
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Tidskriftsartikel (refereegranskat)abstract
- Gasoline and gasoline-ethanol sprays from an outward-opening piezo-injector were studied in a constant volume/pressure chamber using high-speed imaging and phase doppler anemometry (PDA) under stratified cold start conditions corresponding to a vehicle ambient temperature of 243 K (-30 °C/-22 °F); in-cylinder air pressure of 5 bar, air temperature of 350 K (-30 °C/-22 °F) and fuel temperature of 243 K. The effects of varying in-cylinder pressure and temperature, fuel injection pressure and fuel temperature on the formation of gasoline, E75 and pure ethanol sprays were investigated. The results indicate that fuel composition affects spray behaviour, but less than expected. Furthermore, varying the temperature of the fuel or the air surrounding the spray also had minor effects. As expected, the fuel injection pressure was found to have the strongest influence on spray formation under stratified conditions.
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| 6. |
- Joelsson, Tobias, et al.
(författare)
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Large Eddy Simulation and Experiments of the Auto-Ignition Process of Lean Ethanol / Air Mixture in HCCI Engines
- 2008
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 1:1, s. 1110-1119
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Tidskriftsartikel (refereegranskat)abstract
- Recent experiments and numerical studies have showed that piston geometry has a significant effect on the homogeneous charge compression ignition (HCCI) process. There are two effects generated by the combustor geometry: the geometry affects the flow/turbulence in the cylinder; the geometry also affects the temperature stratification. The temperature stratification is more directly responsible for the observed alteration of the auto-ignition process. To clarify this issue further we present in this paper a study of two engines with the same geometry but difference ways of cooling. Measurement of the two engines~a metal engine and quartz piston engine, both with the same piston bowl geometry~is carried out. Large eddy simulation (LES) is used to simulate the flow, the temperature field and the auto-ignition process in the two engines. The fuel is ethanol with a relative air/fuel ratio of 3.3. It is found that lower temperature stratification is established in the metal engine under similar conditions as the optical quartz engine due to the more effective cooling of the piston in the metal engine configuration. The combustion phasing in the two engines is the same by controlling the intake temperature. Both measurements and LES show a more rapid auto-ignition in the metal engine than in the optical engine with the same piston geometry. This confirms the conclusion that large temperature stratification can decrease the pressure-rise-rate and thereby increase the load of HCCI engines. The dependence of temperature stratification on the wall temperature and intake temperature is systematically studied using LES.
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| 7. |
- Kaiadi, Mehrzad, et al.
(författare)
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Closed-Loop Combustion Control for a 6-Cylinder Port-Injected Natural-gas Engine
- 2009
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 1:1, s. 1232-1241
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Tidskriftsartikel (refereegranskat)abstract
- High EGR rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy-duty spark ignition engines. With stoichiometric conditions a three-way catalyst can be used which means that regulated emissions can be kept at very low levels. Obtaining reliable spark ignition is difficult however with high pressure and dilution. There will be a limit to the amount of EGR that can be tolerated for each operating point. Open-loop operation based on steady state maps is difficult since there is substantial dynamics both from the turbocharger and from the wall heat interaction. The proposed approach applies standard closed-loop lambda control for controlling the overall air/fuel ratio for a heavy-duty, 6-cylinder, port-injected natural gas engine. A closed-loop load control is also applied for keeping the load at a constant level when using EGR. Furthermore, cylinder pressure-based dilution limit control is applied on the EGR in order to keep the coefficient of variation at the desired level of 5%. This way confirms that the EGR ratio is kept at its maximum stable level all times. Pumping losses decrease due to the further opening of the throttle, thereby the gas exchange efficiency improves and since the regulator keeps track of the changes the engine all the time operates in a stable region. Our findings show that excellent steady-state performance can be achieved using closed-loop combustion control for keeping the EGR level at the highest level while the stability level is still good enough.
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| 8. |
- Kaiadi, Mehrzad, et al.
(författare)
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How hythane with 25% Hydrogen can affect the Combustion in a 6-Cylinder Natural-Gas Engine
- 2010
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 3:2, s. 47-59
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Tidskriftsartikel (refereegranskat)abstract
- Using alternative fuels like Natural Gas (NG) has shown good potentials on heavy duty engines. Heavy duty NG engines can be operated either lean or stoichiometric diluted with EGR. Extending Dilution limit has been identified as a beneficial strategy for increasing efficiency and decreasing emissions. However dilution limit is limited in these types of engines because of the lower burnings rate of NG. One way to extend the dilution limit of a NG engine is to run the engine on Hythane (natural gas + some percentage hydrogen). Previously effects of Hythane with 10% hydrogen by volume in a stoichiometric heavy duty NG engine were studied and no significant changes in terms of efficiency and emissions were observed. This paper presents results from measurements made on a heavy duty 6-cylinder NG engine. The engine is operated with NG and Hythane with 25% hydrogen by volume and the effects of these fuels on the engine performance are studied. Different experiments were designed and performed to investigate the parameters like knocking margin, dilution limit, lean limit, different efficiencies, emissions and maximum load of the engine. The experiments were performed successfully and the results showed modest improvement in lean, and dilution limit. Slightly changes in emissions and knocking margins are also observed.
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| 9. |
- Kaiadi, Mehrzad, et al.
(författare)
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Using Hythane as a Fuel in a 6-Cylinder Stoichiometric Natural-gas Engine
- 2009
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 2:1, s. 932-939
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Tidskriftsartikel (refereegranskat)abstract
- Combination of right EGR rates with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark-ignited natural gas engines. With stoichiometric conditions a three way catalyst can be used which means that regulated emissions can be kept at very low levels. However dilution limit is limited in these types of engines because of the lower burnings rate of natural gas with higher EGR rates. One way to extend the dilution limit of a natural gas engine is to run the engine with Hythane (natural gas+ some percentage hydrogen). Previously benefits of hydrogen addition to a Lean Burn natural-gas fueled engine was investigated [1] however a complete study for stoichiometric operation was not performed.This paper presents measurements made on a heavy duty 6-cylinder natural gas engine. Three different experiments were designed and tested to investigate first of all if the engine encounters too severe knocking problems, second how and why, Hythane affect the running and finally how lean limit and dilution limit will be improved. The experiments were performed successfully and the results showed no significant differences between natural gas and Hythane in terms of efficiency and emissions when engine operates stoichiometric.
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| 10. |
- Kösters, Anne, 1983, et al.
(författare)
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A Numerical Study of the Effect of EGR on Flame Lift-off in n-Heptane Sprays Using a Novel PaSR Model Implemented in OpenFOAM
- 2012
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 5:2, s. 604-610
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Tidskriftsartikel (refereegranskat)abstract
- The effect of exhaust gas recirculation (EGR) on flame lift-off in non-stationary n-heptane sprays was studied under Diesel engine-like conditions using numerical simulation involving complex chemistry and a novel partially stirred reactor (PaSR) model of subgrid turbulence-chemistry interaction. The flame-stabilization mechanism is a result of complex physical and chemical interactions and cannot be described by a simplified theory. To leading order it is determined by the chemical reaction time at the leading edge, the turbulent diffusivity, and the flow velocity; so that there exists a balance between the local convection velocity and the triple-flame propagation speed. In this study of ignition and flame formation and stabilization processes, the VSB2 stochastic blob-and-bubble spray model was used in combination with the volume reactor fraction model (VRFM) implemented in OpenFOAM. The reacting volume fraction in the VRFM was determined by solving for mixture fraction, progress variable, and their variances in order to estimate the non-uniformities of the fluid cell; rather than simply taking the ratio of the mixing and chemistry time-scales. The chemistry is described by a reduced n-heptane mechanism with 36 species involved in 81 reactions. The simulated lift-off trends are compared to available experimental data from the Engine Combustion Network, Sandia National Laboratories [1].
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