The Experts below are selected from a list of 15723 Experts worldwide ranked by ideXlab platform
Theodosios Korakianitis - One of the best experts on this subject based on the ideXlab platform.
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effect of Pilot Fuel quantity and type on performance and emissions of natural gas and hydrogen based combustion in a compression ignition engine
International Journal of Hydrogen Energy, 2014Co-Authors: D. R. Emberson, R J Crookes, Shahid Imran, Balazs Ihracska, Dongsheng Wen, Theodosios KorakianitisAbstract:Natural gas and hydrogen have been extensively tested in dual Fuel mode in a compression ignition engine. Many studies conclude that the emissions, especially those oxides of nitrogen (NOx) are expected to form in the region around the Pilot spray where high temperatures exist and the equivalence ratio is close to stoichiometric. The effect of changing the Pilot Fuel quantity has not been widely reported. This study investigates the effect of changing Pilot Fuel quantity, and type and the effect of this change on various combustion (ignition delay, in-cylinder pressure and rate of energy release) and emission (specific NOx and hydrocarbons) parameters. Dual Fueling of natural gas and hydrogen exhibit an increased ignition delay compared to the ignition delay exhibited by the Pilot Fuel at similar operating conditions. For dual Fueling cases, the ignition delay is reduced as the quantity of Pilot Fuel is increased.
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Natural gas Fueled compression ignition engine performance and emissions maps with diesel and RME Pilot Fuels
Applied Thermal Engineering, 2014Co-Authors: Syahrul Imran, D. R. Emberson, D. S. Wen, Roy J. Crookes, Antonio Diez, Theodosios KorakianitisAbstract:When natural gas is port/manifold injected into a compression ignition engine, the mixture of air and the natural gas is compressed during the compression stroke of the engine. Due to the difference in the values of specific heat capacity ratio between air and natural gas, the temperature and pressure at the time of Pilot Fuel injection are different when compared to a case where only air is compressed. Also, the presence of natural gas affects the peak in-cylinder (adiabatic flame) temperature. This significantly affects the performance as well as emissions characteristics of natural gas based dual Fueling in CI engine. Natural gas has been extensively tested in a single cylinder compression ignition engine to obtain performance and emissions maps.Two Pilot Fuels, diesel and RME, have been used to Pilot natural gas combustion. The performance of the two liquid Fuels used as Pilots has also been assessed and compared. Tests were conducted at 48 different operating conditions (six different speeds and eight different power output conditions for each speed) for single Fueling cases. Both the diesel and RME based single Fueling cases were used as baselines to compare the natural gas based dual Fueling where data was collected at 36 operating conditions (six different speeds and six different power output conditions for each speed). Performance and emissions characteristics were mapped on speed vs brake power plots. The thermal efficiency values of the natural gas dual Fueling were lower when compared to the respective Pilot Fuel based single Fueling apart from the highest powers. The effect of engine speed on volumetric efficiency in case of the natural gas based dual Fueling was significantly different from what was observed with the single Fueling. Contours of specific NOX for diesel and RME based single Fueling differ significantly when these Fuels were used to Pilot natural gas combustion. For both of the single Fueling cases, maximum specific NOX were centered at the intersection of medium speeds and medium powers and they decrease in all directions from this region of maximum values. On the other hand, an opposite trend was observed with dual Fueling cases where minimum specific NOX were observed at the center of the map and they increase in all direction from this region of minimum NOX. RME Piloted specific NOX at the highest speeds were the only exception to this trend. Higher specific HC and lower specific CO2 emissions were observed in case of natural gas based dual Fueling. The emissions were measured in g/MJ of engine power.
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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, Roy 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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natural gas Fueled spark ignition si and compression ignition ci engine performance and emissions
Progress in Energy and Combustion Science, 2011Co-Authors: Theodosios Korakianitis, A.m. Namasivayam, Roy J. CrookesAbstract:Abstract Natural gas is a fossil Fuel that has been used and investigated extensively for use in spark-ignition (SI) and compression-ignition (CI) engines. Compared with conventional gasoline engines, SI engines using natural gas can run at higher compression ratios, thus producing higher thermal efficiencies but also increased nitrogen oxide (NO x ) emissions, while producing lower emissions of carbon dioxide (CO 2 ), unburned hydrocarbons (HC) and carbon monoxide (CO). These engines also produce relatively less power than gasoline-Fueled engines because of the convergence of one or more of three factors: a reduction in volumetric efficiency due to natural-gas injection in the intake manifold; the lower stoichiometric Fuel/air ratio of natural gas compared to gasoline; and the lower equivalence ratio at which these engines may be run in order to reduce NO x emissions. High NO x emissions, especially at high loads, reduce with exhaust gas recirculation (EGR). However, EGR rates above a maximum value result in misfire and erratic engine operation. Hydrogen gas addition increases this EGR threshold significantly. In addition, hydrogen increases the flame speed of the natural gas–hydrogen mixture. Power levels can be increased with supercharging or turbocharging and intercooling. Natural gas is used to power CI engines via the dual-Fuel mode, where a high-cetane Fuel is injected along with the natural gas in order to provide a source of ignition for the charge. Thermal efficiency levels compared with normal diesel-Fueled CI-engine operation are generally maintained with dual-Fuel operation, and smoke levels are reduced significantly. At the same time, lower NO x and CO 2 emissions, as well as higher HC and CO emissions compared with normal CI-engine operation at low and intermediate loads are recorded. These trends are caused by the low charge temperature and increased ignition delay, resulting in low combustion temperatures. Another factor is insufficient penetration and distribution of the Pilot Fuel in the charge, resulting in a lack of ignition centers. EGR admission at low and intermediate loads increases combustion temperatures, lowering unburned HC and CO emissions. Larger Pilot Fuel quantities at these load levels and hydrogen gas addition can also help increase combustion efficiency. Power output is lower at certain conditions than diesel-Fueled engines, for reasons similar to those affecting power output of SI engines. In both cases the power output can be maintained with direct injection. Overall, natural gas can be used in both engine types; however further refinement and optimization of engines and Fuel-injection systems is needed.
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hydrogen dual Fuelling of compression ignition engines with emulsified biodiesel as Pilot Fuel
International Journal of Hydrogen Energy, 2010Co-Authors: Theodosios Korakianitis, A.m. Namasivayam, R J CrookesAbstract:Dual-Fuel compression ignition (CI) engine operation with hydrogen is a promising method of using hydrogen gas in CI engines via high-cetane Pilot Fuel ignition. However, hydrogen dual-Fuel operation with neat Pilot Fuels typically produce: high NOx emissions; and high combustion chamber pressure rise rates (leading to increased “Diesel knock” tendencies). While water-in-Fuel emulsions have been used during normal CI engine operation to cool the charge and slow combustion rates in an effort to reduce NOx emissions, these water-in-Fuel emulsions have not been tested as Pilot Fuels during hydrogen dual-Fuel combustion. In this work two water-in-biodiesel emulsions are tested as Pilot Fuels during hydrogen dual-Fuel operation. Hydrogen dual-Fuel operation generally produces at best comparable thermal efficiencies compared with normal CI engine operation, while the emulsified biodiesel Pilot Fuels generally increase thermal efficiencies when compared with the neat biodiesel Pilot Fuel during dual-Fuel operation. There is also a clear reduction in NOx emissions with emulsified Pilot Fuel use compared with the neat Pilot Fuel. The thermal efficiency increase is more apparent at higher engine speeds, while the NOx reduction is more apparent at lower speeds. This is due to two conflicting effects (exclusive to emulsified Pilot Fuel) that occur in tandem. The first is the cooling effect of water vapourisation on the charge, while the second is the microexplosion phenomenon which enhances Fuel-air mixing. The NOx emission reduction is due to the emulsified Pilot Fuel lowering pressure rise rates compared with the neat Pilot Fuel, while the efficiency increase is due to a more homogeneous charge resulting from the violent microexplosion of the emulsified Pilot Fuel. Smoke, CO, HC and CO2 emissions remain comparable to neat Pilot Fuel tests. Overall, emulsified Pilot Fuels can reduce NOx emissions and increase thermal efficiencies, however not at the same instance and under different operating conditions. The general trends of reduced power output, reduced CO2 and increased water vapour emission during hydrogen dual-Fuel operation (with neat Pilot Fuels) are also maintained.
Mohand Tazerout - One of the best experts on this subject based on the ideXlab platform.
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knock characterization and development of a new knock indicator for dual Fuel engines
Energy, 2017Co-Authors: Mohand Said Lounici, M A Benbellil, Khaled Loubar, D C Niculescu, Mohand TazeroutAbstract:Abstract Dual-Fuel mode is a promising technique for natural gas utilization in internal combustion engines. However, for high loads operation, the engine risks to go through a hazardous knocking regime. Knock phenomenon is an abnormal combustion that can cause some disagreeable effects in engines where it occurs. It can even induce brutal irreparable engine damage under severe knocking conditions. The present paper aims first to highlight and characterize knock in dual-Fuel engines Fueled with natural gas as main Fuel and diesel as Pilot Fuel. Description of this phenomenon is investigated in this type of engines. Knock behavior in dual-Fuel engine is compared to spark ignition engine case. Cyclical variability of this phenomenon is studied. A new knock indicator, based on in-cylinder pressure analysis, is proposed in order to identify and evaluate knock in dual-Fuel engines. In addition, knock effects on heat release, cylinder wall temperature and engine performance and emissions are examined. New techniques to delay knock appearance in this type of engines are investigated. It is found that the increase in Pilot Fuel quantity is an effective technique to delay knock onset in NG dual-Fuel engines.
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hydrogen supplemented natural gas effect on a di diesel engine operating under dual Fuel mode with a biodiesel Pilot Fuel
International Journal of Hydrogen Energy, 2017Co-Authors: L. Tarabet, Mohand Said Lounici, Khaled Loubar, K. Khiari, Rekia Bouguessa, Mohand TazeroutAbstract:Abstract In order to slow down the continuing environmental deterioration, regulations for pollutant emissions limitations are increasingly rigorous. The development of new alternative Fuels for internal combustion engines is a very interesting solution not only to overcome the pollution problem but also because of the petroleum shortage. In this context, the present work investigates the improvement of a DI diesel engine operating at constant speed (1500 rpm) and under dual Fuel mode with eucalyptus biodiesel and natural gas (NG) enriched by various H2 quantities (15, 25 and 30 by v%). The eucalyptus biodiesel quantity injected into the engine cylinder is kept constant, to supply around 10% of the engine nominal power, for all examined engine loads. The engine load is further increased using only the gaseous Fuel (NG+H2), which is introduced with the intake air. The effect of H2/NG blending ratio on the combustion parameters, performance and pollutant emissions of the engine is investigated and compared with those of pure NG case. An important benefit in terms of brake specific Fuel consumption, reaching a decrease of 4–10% with the 25% H2 blend compared to the pure NG case, is achieved. Concerning the pollutant emissions, NG enrichment with H2 is an efficient solution to enhance the combustion process and hence reduce carbon monoxide, unburned hydrocarbon and soot emissions at high loads where they are important for pure NG. However for the nitrogen oxide emissions, NG blending with H2 is attractive only at low and medium loads where their levels are lower than pure NG.
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Experimental investigation of the equivalence ratio influence on combustion, performance and exhaust emissions of a dual Fuel diesel engine operating on synthetic biogas Fuel
Energy Conversion and Management, 2017Co-Authors: F.z. Aklouche, Khaled Loubar, A. Bentebbiche, Sary Awad, Mohand TazeroutAbstract:In this work, an experimental investigation was conducted to analyze dual Fuel (DF) engine operation using synthetic biogas Fuel under high load at constant percentage energy substitution rate (PES). The performance, ignition delay, and other combustion characteristics of engines operating in dual Fuel mode (biogas/diesel), are compared to the conventional mode. The synthetic biogas, composed of 60% methane and 40% carbon dioxide, is the primary Fuel which is blended with the air in the engine inlet manifold, whereas the Pilot Fuel is diesel. The equivalence ratio (Fuel-air) (ϕ) was varied by changing air flow rate while the energy introduced into the engine remained constant for all the examined cases. Combustion analysis showed that with increasing ϕ, the ignition delay tends to become longer and the peak of heat release rate was increased. Furthermore, as ϕ increased from 0.35 to 0.7, HC and CO emissions were reduced by 77% and 58% respectively. The NOx emissions decreased at 60% PES by 24% while the BTE was improved by 13%.
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experimental investigation of di diesel engine operating with eucalyptus biodiesel natural gas under dual Fuel mode
Fuel, 2014Co-Authors: L. Tarabet, Mohand Said Lounici, Khaled Loubar, K. Khiari, T. Belmrabet, Mohand TazeroutAbstract:With the gradual depletion of petroleum and environmental degradation, intensive research activity has been addressed to the utilization of alternative Fuels in internal combustion engines. In the present work, an experimental investigation is carried out to study the effect of eucalyptus biodiesel and natural gas under dual Fuel combustion mode on the performance and the exhaust emissions of a single cylinder DI diesel engine. The natural gas (NG) is inducted with the intake air through the inlet manifold. The liquid Pilot Fuel (eucalyptus biodiesel or diesel Fuel) is injected into the combustion chamber to cover approximately 10% of the maximum power output. Then, keeping constant the Pilot Fuel flow rate, the power output is further increased using only natural gas. The combustion characteristics (cylinder pressure, ignition delay and heat release rate), performance and exhaust emissions of the dual Fuel mode (NG–diesel Fuel and NG–biodiesel) are compared with those of conventional diesel engine mode at various load conditions. The combustion analysis has shown that biodiesel as Pilot Fuel exhibits similar pressure–time history, with highest peak, as diesel Fuel in conventional and dual Fuel modes. The performance and pollutant emission results show that, compared to diesel Fuel in dual Fuel mode, the use of eucalyptus biodiesel as Pilot Fuel reduces the high emission levels of unburned hydrocarbon (HC), carbon monoxide (CO) and carbon dioxide (CO2) particularly at high engine loads. However this is accompanied by an increase in the brake specific Fuel consumption (BSFC) and the nitrogen oxide (NOx) emissions, which can be explained by the lower calorific value and the oxygen presence in the molecule of the eucalyptus biodiesel, respectively.
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Towards improvement of natural gas-diesel dual Fuel mode: An experimental investigation on performance and exhaust emissions
Energy, 2014Co-Authors: Mohand Said Lounici, Khaled Loubar, L. Tarabet, Mourad Balistrou, Dan-catalin Niculescu, Mohand TazeroutAbstract:Abstract The use of natural gas in compression ignition engines as supplement to liquid diesel in a dual Fuel combustion mode is a promising technique. In this study, the effect of \DF\ (dual Fuel) operating mode on combustion characteristics, engine performances and pollutants emissions of an existing diesel engine using natural gas as primary Fuel and neat diesel as Pilot Fuel, has been examined. At moderate and relatively high loads, the results show very interesting behavior of dual Fuel operating mode in comparison to conventional diesel, both for engine performance and emissions. It showed a simultaneous reduction of soot and \NOx\ species over a large engine operating area. Moreover, it showed the possibility to obtain lower \BSFC\ (brake specific Fuel consumption) than conventional diesel engine. However, this mode presents some deficits at low loads, especially concerning unburned hydrocarbons and carbon monoxide emissions. Understanding those deficiencies is a key of such engines improvement. Some suggestions for new measures towards \DF\ mode improvement are deduced.
Gilles Bruneaux - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of Pilot Fuel combustion in dual Fuel engines part 1 thermodynamic analysis of combustion phenomena
Fuel, 2019Co-Authors: Aleš Srna, Kai Herrmann, Konstantinos Boulouchos, Beat Von Rotz, Gilles BruneauxAbstract:Abstract The Pilot-Fuel auto-ignition and combustion in compressed methane/air mixtures are investigated. Experiments were performed in an optically accessible rapid compression-expansion machine featuring quiescent charge conditions and a single-hole coaxial diesel injector mounted on the cylinder periphery. It enabled thermodynamic analysis of the Pilot-Fuel combustion without these phenomena being masked by the rapid premixed-flame propagation like in the engine test rigs with turbulent charge. The aim of this study is to elucidate the first-order influences of charge and Pilot-Fuel parameters on the ignition delay and transition into the premixed flame propagation. For this purpose, a comprehensive measurement matrix including variations of the premixed Fuel equivalence ratio, charge temperature, and oxygen content as well as the variation of Pilot injection duration is tested. The heat release rate (HRR) metrics describing the Pilot-Fuel combustion duration, peak HRR, and cumulative HRR during the Pilot-Fuel combustion are derived. Correlations of the HRR metrics to the ignition delay, Pilot-Fuel mixing state at ignition and the volume of the Pilot-Fuel jet are investigated. Methane is found to increase the ignition delay and prolong the Pilot-Fuel combustion duration. This effect is amplified for Pilot-injection strategies with leaner Pilot-Fuel mixtures at ignition or in the case of reduced charge oxygen content. Despite the reduced Pilot-Fuel reactivity the co-combustion of entrained methane leads to higher peak-HRR, except in the reduced charge oxygen cases, where the excessively reduced mixture reactivity with the introduction of methane leads even to a reduced peak-HRR. The phenomenology of the dual-Fuel combustion process is described in Part 1, whereas Part 2 of this work aims at improving the understanding of the underlying processes by application of advanced optical diagnostic methods.
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Effect of methane on Pilot-Fuel auto-ignition in dual-Fuel engines
Proceedings of the Combustion Institute, 2019Co-Authors: Aleš Srna, Michele Bolla, Yuri Wright, Kai Herrmann, Sushant Pandurangi, Rolf Bombach, Konstantinos Boulouchos, Gilles BruneauxAbstract:The ignition behavior of n-dodecane micro-Pilot spray in a lean-premixed methane/air charge was investigated in an optically accessible Rapid Compression-Expansion Machine at dual-Fuel engine-like pressure/temperature conditions. The Pilot Fuel was admitted using a coaxial single-hole 100 µm injector mounted on the cylinder periphery. Optical diagnostics include combined high-speed CH2O-PLIF (10 kHz) and Schlieren (80 kHz) imaging for detection of the first-stage ignition, and simultaneous high-speed OH* chemiluminescence (40 kHz) imaging for high-temperature ignition. The aim of this study is to enhance the fundamental understanding of the interaction of methane with the auto-ignition process of short Pilot-Fuel injections. Addition of methane into the air charge considerably prolongs ignition delay of the Pilot spray with an increasing effect at lower temperatures and with higher methane/air equivalence ratios. The temporal separation of the first CH2O detection and high-temperature ignition was found almost constant regardless of methane content. This was interpreted as methane mostly deferring the cool-flame reactivity. In order to understand the underlying mechanisms of this interaction, experimental investigations were complemented with 1D-flamelet simulations using detailed chemistry, confirming the chemical influence of methane deferring the reactivity in the Pilot-Fuel lean mixtures. This shifts the onset of first-stage reactivity towards the Fuel-richer conditions. Consequently, the onset of the turbulent cool-flame is delayed, leading to an overall increased high-temperature ignition delay. Overall, the study reveals a complex interplay between entrainment, low T and high T chemistry and micro-mixing for dual-Fuel auto-ignition processes for which the governing processes were identified
Xiangyu Meng - One of the best experts on this subject based on the ideXlab platform.
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comparative study of Pilot Fuel property and intake air boost on combustion and performance in the cng dual Fuel engine
Fuel, 2019Co-Authors: Xiangyu Meng, Yihui Zhou, Hua Tian, Jiangping Tian, Wuqiang LongAbstract:Abstract As the Pilot Fuel property and equivalence ratio of the mixture exhibit significant effect on the combustion and emission characteristics in the dual-Fuel operation mode with compressed natural gas (CNG), in this work, bio-Fuel of n-butanol as the additive in diesel in conjunction with boost air intake pressure (Pin) was studied at indicated mean effective pressure (IMEP) of 10 bar. Various n-butanol blending ratios in the Pilot Fuel of B0 (pure diesel as the Pilot Fuel), B10 (90% diesel/10% n-butanol by volume basis as the Pilot Fuel), B20 and B30 were compared at Pin from 1.1 to 1.5 bar under two CNG substitution rates of 50% (CNG50) and 70% (CNG70). The experimental results revealed that for the increasing n-butanol content and decreasing Pin, the ignition delay is prolonged, and combustion duration becomes shorter. While CA50 is advanced with diesel/n-butanol as the Pilot Fuel at relatively higher Pin, e.g. 1.4 and 1.5 bar. Compared to CNG70, CNG50 can enhanced the indicated thermal efficiency (ITE), but also inducing higher maximum pressure rising rate (MPRR). Adding n-butanol can further improve ITE at 50% CNG relatively to pure diesel. For the emission characteristics, the THC and CO emissions can be reduced by adding n-butanol in the Pilot Fuel due to more homogeneous distribution of Pilot Fuel. However, much higher n-butanol content, such as B20 and B30, could lead to higher NOx emission. In addition, it is interesting to find that B10CNG50 can improve ITE, NOx, THC and CO simultaneously compared to B0CNG50 at relatively higher Pin.
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experimental study of using additive in the Pilot Fuel on the performance and emission trade offs in the diesel cng methane emulated dual Fuel combustion mode
Applied Thermal Engineering, 2019Co-Authors: Xiangyu Meng, Wuqiang Long, Yihui Zhou, Hua Tian, Jiangping Tian, Chia-fon LeeAbstract:Abstract In this work, diesel-n-butanol blends as the Pilot Fuel were studied to explore the possibility of improving the performance and emissions in the dual-Fuel combustion mode with CNG, and the trade-offs among NOx, THC and CO were also discussed. The Pilot Fuels including B0 (pure diesel), B10 (90% diesel/10% n-butanol) and B20 (80% diesel/20% n-butanol) were compared under two engine loads. The experiments were conducted by sweeping a wide Pilot Fuel start of injection (SOI) timings at two CNG substitution rates for each load. For 5 bar indicated mean effective pressure (IMEP), B10CNG40 (at the 40% CNG substitution rate) reveals the highest indicated thermal efficiency (ITE) and lowest THC emissions. While it results in slightly higher NOx emission. B20CNG70 can significantly reduce the NOx emission due to better homogeneity and higher evaporation latent heat of n-butanol. The obvious trade-offs between NOx and THC, NOx and CO can be observed at the retarded Pilot Fuel SOI timings. For 7.5 bar IMEP, B10CNG60 and B20CNG60 can improve ITE and lower the THC emissions, while maintaining the equivalent level of NOx emission relative to the cases at the 80% CNG substitution rate. Adding n-butanol leads to the trade-off between THC and CO emissions.
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experimental study of using additive in the Pilot Fuel on the performance and emission trade offs in the diesel cng methane emulated dual Fuel combustion mode
Applied Thermal Engineering, 2019Co-Authors: Xiangyu Meng, Wuqiang Long, Yihui Zhou, Hua Tian, Mingshu Bi, Jiangping TianAbstract:Abstract In this work, diesel-n-butanol blends as the Pilot Fuel were studied to explore the possibility of improving the performance and emissions in the dual-Fuel combustion mode with CNG, and the trade-offs among NOx, THC and CO were also discussed. The Pilot Fuels including B0 (pure diesel), B10 (90% diesel/10% n-butanol) and B20 (80% diesel/20% n-butanol) were compared under two engine loads. The experiments were conducted by sweeping a wide Pilot Fuel start of injection (SOI) timings at two CNG substitution rates for each load. For 5 bar indicated mean effective pressure (IMEP), B10CNG40 (at the 40% CNG substitution rate) reveals the highest indicated thermal efficiency (ITE) and lowest THC emissions. While it results in slightly higher NOx emission. B20CNG70 can significantly reduce the NOx emission due to better homogeneity and higher evaporation latent heat of n-butanol. The obvious trade-offs between NOx and THC, NOx and CO can be observed at the retarded Pilot Fuel SOI timings. For 7.5 bar IMEP, B10CNG60 and B20CNG60 can improve ITE and lower the THC emissions, while maintaining the equivalent level of NOx emission relative to the cases at the 80% CNG substitution rate. Adding n-butanol leads to the trade-off between THC and CO emissions.
Jiangping Tian - One of the best experts on this subject based on the ideXlab platform.
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comparative study of Pilot Fuel property and intake air boost on combustion and performance in the cng dual Fuel engine
Fuel, 2019Co-Authors: Xiangyu Meng, Yihui Zhou, Hua Tian, Jiangping Tian, Wuqiang LongAbstract:Abstract As the Pilot Fuel property and equivalence ratio of the mixture exhibit significant effect on the combustion and emission characteristics in the dual-Fuel operation mode with compressed natural gas (CNG), in this work, bio-Fuel of n-butanol as the additive in diesel in conjunction with boost air intake pressure (Pin) was studied at indicated mean effective pressure (IMEP) of 10 bar. Various n-butanol blending ratios in the Pilot Fuel of B0 (pure diesel as the Pilot Fuel), B10 (90% diesel/10% n-butanol by volume basis as the Pilot Fuel), B20 and B30 were compared at Pin from 1.1 to 1.5 bar under two CNG substitution rates of 50% (CNG50) and 70% (CNG70). The experimental results revealed that for the increasing n-butanol content and decreasing Pin, the ignition delay is prolonged, and combustion duration becomes shorter. While CA50 is advanced with diesel/n-butanol as the Pilot Fuel at relatively higher Pin, e.g. 1.4 and 1.5 bar. Compared to CNG70, CNG50 can enhanced the indicated thermal efficiency (ITE), but also inducing higher maximum pressure rising rate (MPRR). Adding n-butanol can further improve ITE at 50% CNG relatively to pure diesel. For the emission characteristics, the THC and CO emissions can be reduced by adding n-butanol in the Pilot Fuel due to more homogeneous distribution of Pilot Fuel. However, much higher n-butanol content, such as B20 and B30, could lead to higher NOx emission. In addition, it is interesting to find that B10CNG50 can improve ITE, NOx, THC and CO simultaneously compared to B0CNG50 at relatively higher Pin.
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experimental study of using additive in the Pilot Fuel on the performance and emission trade offs in the diesel cng methane emulated dual Fuel combustion mode
Applied Thermal Engineering, 2019Co-Authors: Xiangyu Meng, Wuqiang Long, Yihui Zhou, Hua Tian, Jiangping Tian, Chia-fon LeeAbstract:Abstract In this work, diesel-n-butanol blends as the Pilot Fuel were studied to explore the possibility of improving the performance and emissions in the dual-Fuel combustion mode with CNG, and the trade-offs among NOx, THC and CO were also discussed. The Pilot Fuels including B0 (pure diesel), B10 (90% diesel/10% n-butanol) and B20 (80% diesel/20% n-butanol) were compared under two engine loads. The experiments were conducted by sweeping a wide Pilot Fuel start of injection (SOI) timings at two CNG substitution rates for each load. For 5 bar indicated mean effective pressure (IMEP), B10CNG40 (at the 40% CNG substitution rate) reveals the highest indicated thermal efficiency (ITE) and lowest THC emissions. While it results in slightly higher NOx emission. B20CNG70 can significantly reduce the NOx emission due to better homogeneity and higher evaporation latent heat of n-butanol. The obvious trade-offs between NOx and THC, NOx and CO can be observed at the retarded Pilot Fuel SOI timings. For 7.5 bar IMEP, B10CNG60 and B20CNG60 can improve ITE and lower the THC emissions, while maintaining the equivalent level of NOx emission relative to the cases at the 80% CNG substitution rate. Adding n-butanol leads to the trade-off between THC and CO emissions.
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experimental study of using additive in the Pilot Fuel on the performance and emission trade offs in the diesel cng methane emulated dual Fuel combustion mode
Applied Thermal Engineering, 2019Co-Authors: Xiangyu Meng, Wuqiang Long, Yihui Zhou, Hua Tian, Mingshu Bi, Jiangping TianAbstract:Abstract In this work, diesel-n-butanol blends as the Pilot Fuel were studied to explore the possibility of improving the performance and emissions in the dual-Fuel combustion mode with CNG, and the trade-offs among NOx, THC and CO were also discussed. The Pilot Fuels including B0 (pure diesel), B10 (90% diesel/10% n-butanol) and B20 (80% diesel/20% n-butanol) were compared under two engine loads. The experiments were conducted by sweeping a wide Pilot Fuel start of injection (SOI) timings at two CNG substitution rates for each load. For 5 bar indicated mean effective pressure (IMEP), B10CNG40 (at the 40% CNG substitution rate) reveals the highest indicated thermal efficiency (ITE) and lowest THC emissions. While it results in slightly higher NOx emission. B20CNG70 can significantly reduce the NOx emission due to better homogeneity and higher evaporation latent heat of n-butanol. The obvious trade-offs between NOx and THC, NOx and CO can be observed at the retarded Pilot Fuel SOI timings. For 7.5 bar IMEP, B10CNG60 and B20CNG60 can improve ITE and lower the THC emissions, while maintaining the equivalent level of NOx emission relative to the cases at the 80% CNG substitution rate. Adding n-butanol leads to the trade-off between THC and CO emissions.