Language：Japanese   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.cattod.2022.06.012

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Fischer–Tropsch synthetic (FT) fuels are expected to be an ideal alternative for diesel fuel to achieve higher thermal efficiency and reduction in exhaust emissions because of their characteristics of being aromatic-free, sulfur-free, and high cetane number. In this study, the effects of chemical compositions and cetane number of FT fuels on diesel engine performance were investigated by using a commercial GTL (Gas-to-Liquids) diesel fuel synthesized by the FT method and blended paraffinic hydrocarbon fuels made to simulate FT fuels with different chemical compositions and cetane numbers. At first, a commercial diesel fuel (JIS No.2) and GTL were examined by varying the intake oxygen concentrations with cooled EGR. Compared with diesel fuel, GTL shows shorter premixed combustion, smaller heat release peak, and longer diffusion combustion duration at both high and medium conditions due to the higher cetane number. Further, by using the GTL, a limited improvement in thermal efficiency and exhaust emission reduction of NOx have been obtained, but no significant reduction in the smoke emissions is achieved, even though FT fuels have been considered smokeless due to their aromatic-free characteristics. Next, three types of paraffinic hydrocarbon fuels with cetane numbers of 78, 57, and 38 were blended as simulated FT fuels and were examined under the same experimental apparatus and operation conditions. For the low cetane number simulated FT fuel (cetane number 38 fuel), the results show that the ignition delay and premixing period are significantly longer at low intake oxygen concentration conditions, meaning that the premixing of low cetane number fuel is more sufficient than other fuels, especially under the high EGR rate conditions, resulting in fewer smoke emissions. Furthermore, with CN38 fuel, an excellent indicated thermal efficiency was obtained at the high load condition. To summarize the results, the low cetane number FT fuel shows a potential to achieve higher thermal efficiency and reduction in exhaust emissions on commercial diesel engines with EGR.

DOI： 10.3390/en15114047

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DOI： 10.1016/j.ijhydene.2022.03.286

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SAGE Publications  

Post fuel is injected to avoid plugging of diesel particulate filters (DPF). However, at advanced post fuel injection timings, the post fuel is partially oxidized in the cylinder under the high temperature conditions and the hydrocarbon supplied to DOC is not sufficient to regenerate the DPF. In this paper, partial oxidation phenomena at advanced post fuel injection timings were investigated with an engine and a high pressure-temperature optical constant volume chamber. In the engine experiments, the oxidation ratio of the post fuel was calculated from the exhaust gas composition. When the post fuel is injected at 30 CA ATDC, 83% of the post fuel is oxidized, however when the injection timing is 60 CA ATDC, the oxidation ratio of the post fuel becomes 2.2% and there is a 40.9% fuel loss mostly due to oil dilution. The reaction speed, in-cylinder temperature, and oxygen concentration (mol/m³) at the post fuel injection timing are related to the partial oxidation ratio of the post fuel. In the experiments with the constant volume chamber, the spray behaviors at the post fuel injections were observed. The ignition delay becomes longer with lower in-cylinder temperature and lower oxygen concentration, and the spray dilution of the post fuel during the ignition delays affects the heat release and the location where the partial oxidation in the chamber occurs. Based on the experimental data of engine speed, oxygen concentration, and in-cylinder temperature at the start of post fuel injection, an experimental formula for the post fuel oxidation ratio based on the Arrhenius equation was suggested by multiple regression analysis of the engine test data.

DOI： 10.1177/14680874221075104

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Marine Engineering  

DOI： 10.5988/jime.56.592

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE Publications  

Improvements of the thermal efficiency in twin shaped semi-premixed diesel combustion mode with premixed combustion in the primary stage and spray diffusive combustion in the secondary stage with multi-stage fuel injection were investigated with experiments and 3D-CFD analysis. For a better understanding of the advantages of this combustion mode, the results were compared with conventional diesel combustion modes, mainly consisting of diffusive combustion. The semi-premixed mode has a higher thermal efficiency than the conventional mode at both the low and medium load conditions examined here. The heat release in the semi-premixed mode is more concentrated at the top dead center, resulting in a significant reduction in the exhaust loss. The increase in the cooling loss is suppressed to a level similar to the conventional mode. In the conventional mode the rate of heat release becomes more rapid and the combustion noise increases with advances in the combustion phase as the premixed combustion with pilot and pre injections and the diffusive combustion with the main combustion occurs simultaneously. In the semi-premixed mode, the premixed combustion with pilot and primary injections and the diffusive combustion with the secondary injection occurs separately in different phases, maintaining a gentler heat release with advances in the combustion phase. The mechanism of the cooling loss suppression with the semi-premixed mode at low load was investigated with 3D-CFD. In the semi-premixed mode, there is a reduction in the gas flow and quantity of the combustion gas near the piston wall due to the suppression of spray penetration and splitting of the injection, resulting in a smaller heat flux.

DOI： 10.1177/14680874211026429

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.fuel.2020.118730

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE Publications  

Diesel particulate filters are used to capture the particulate matter in engine exhaust, and the post fuel is injected for a regular regeneration of the diesel particulate filter to avoid plugging of the diesel particulate filter with the particulate matter. The concept of the post fuel injection is as follows: the post fuel is injected in the expansion stroke, the vaporized fuel gas is oxidized by the diesel oxidation catalyst, here the high temperature gas oxidizes the particulate matter on the diesel particulate filter, and the diesel particulate filter is regenerated. However, the post fuel impinges and adheres on the cylinder wall due to the low temperature and pressure conditions in the expansion stroke in actual engine operation and this causes diesel engine lubricant oil dilution, the deterioration of fuel consumption characteristics in diesel engines, as well as ash plugging of the diesel particulate filter. In this article, the post fuel spray behavior and adhesion on oil-wet cylinder liners were investigated with a high pressure–temperature optical constant volume chamber instead of engine tests. The in-cylinder temperature and pressure at the 30, 60, and 90 °CA after top dead center, commonly employed in post fuel injection timings, were measured in engine operation. To create the post fuel injection conditions of diesel engines in the constant volume chamber, pre-mixed gas containing ethylene, oxygen, and nitrogen is introduced into the chamber and ignited by the spark plug. Then, fuel masses of 0.5, 1.0, and 1.5 mg per injection hole at the after top dead center settings were injected to a wall adhesion plate with a 5-μm thick oil film that simulates the surface of the cylinder liner and the post fuel impinges on and splashes oil away from the oil film on the cylinder wall. The quantities of splashed oil and adhering fuel on the wall adhesion plate were measured by a precision balance and a thermostatic chamber. With the early post injection, most of the injected fuel vaporizes without penetrating to the cylinder liner and gaseous diesel fuel is condensed on the cylinder wall; however, with the late post fuel injections, the strong penetration of liquid fuel reaches the cylinder wall, and much engine oil becomes splashed away. The droplet size of the fuel spray was measured by telescope ultra-high resolution image analysis with a digital single-lens reflex camera, and the fuel impingement phenomena on the cylinder wall are explained by the Weber number, calculated from velocity and diameter values, droplet density, and surface tension.

DOI： 10.1177/1468087420914142

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Publishing type：Research paper (scientific journal)   Publisher：SAGE Publications  

Pre-mixed diesel combustion has the potential of offering high thermal efficiency with low emissions; however, this may result in loud combustion noise because of the high maximum rate of pressure rise. Combustion noise and thermal efficiency work in a trade-off relation, and it has not been possible to achieve high thermal efficiency with low combustion noise, so far. Our laboratory has worked on combustion noise simulations calculated from the heat release history, and it is now possible to calculate a heat release shape for high thermal efficiency with low combustion noise. In this article, the objective of the research is the reduction of combustion noise by multiple fuel injections with high indicated thermal efficiency for a wide range of engine speeds and loads. The engine employed in the simulations and experiments is a supercharged, single-cylinder direct-injection diesel engine, with a high-pressure common rail fuel injection system. The heat release is approximated by Wiebe functions, and the combustion noise and indicated thermal efficiency are calculated in simulations. The engine operational range was divided into 12 conditions, four engine speed conditions each at three engine load conditions, and the optimum heat release shape for low combustion noise with high indicated thermal efficiency was calculated by a genetic-based algorithm method. The parameters for the genetic-based algorithm simulation were the number of injections, each injection timing, the heating value in each heat release, and the combustion period of each injection. The optimum heat release shape is a delta triangle (Δ)-shaped heat release (the heat release increase in the expansion stroke) with a high degree of constant volume for all conditions; however, the optimum number of heat releases and the injection timing are different depending on the engine speed and load conditions. The simulated results were confirmed by engine tests.

DOI： 10.1177/1468087419866069

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Post fuel injection in the expansion stroke is used for diesel particulate filter regeneration; however, fuel spray impinges on the cylinder liner due to the low temperature and pressure conditions. Fuel adhesion and fuel flowing down across the cylinder liner, the so-called “wall-flow,” was observed by high-speed video images, and this adhesion is a cause of diesel engine lubricant oil dilution and the deterioration of fuel consumption in diesel engines. In this article, the fuel adhesion and the wall-flow of post diesel fuel injections were investigated with a high pressure-temperature constant volume optical chamber. The in-cylinder temperatures and pressures at 30, 60, and 90 °CA ATDCs, conditions commonly employed in post fuel injection timings, were measured by an actual engine, and similar conditions were created in the constant volume chamber by the combustion of a pre-mixed gas of ethylene, oxygen, and nitrogen. Fuel masses of 0.6, 1.1, and 1.7 mg per hole were injected at each ATDC setting. The weight of the adhered fuel on the wall and the fuel in the piston-cylinder crevice were measured by precision balance, and the liquid–vapor phases in the spray were observed by Mie scattering and shadowgraph methods. To measure the thickness of the adhered fuel on the cylinder wall, the laser-induced fluorescence method was employed. The results show that the fuel spray penetration and adhesion on the cylinder wall were different in the test conditions investigated here. With the early post injection, most of the injected fuel vaporizes without penetrating to the cylinder liner and gaseous diesel fuel is condensed on the cylinder wall. A thin and widely spread out fuel film is formed on the cylinder wall; however, no wall-flow could be confirmed by the high-speed video images. With late post fuel injections, the strong penetration of liquid fuel reaches the cylinder wall, and a thick and widely spread out fuel film was formed on the cylinder wall and the wall-flow phenomenon was observed here. However, the quantity of fuel involved in the wall-flow was smaller than that of the fuel adhering to the cylinder wall. The effects of in-cylinder pressure and temperature on the fuel adhesion on the cylinder wall were investigated. With the increase in pressure and temperature, the quantity of adhering fuel was reduced, suggesting that the boost pressure increase by turbo charging and a higher engine load is effective to reduce fuel adhesion. Furthermore, the effects of multiple post fuel injections on fuel adhesion to the cylinder wall were investigated, maintaining the total fuel injection amounts. With increases in the number of fuel injections, the total percentage of adhering post fuel on the cylinder wall was reduced. In the multiple fuel injections, it was observed that fuel motion takes place during the spray pass after the first and second fuel injections and that the penetration length of the second and third fuel sprays increases.

DOI： 10.1177/1468087419855200

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DOI： 10.1016/j.fuel.2018.10.042

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DOI： 10.4271/2019-01-0024

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

To investigate the effect of the fuel injection pressure on the cooling loss in a diesel engine, the present study evaluated the turbulent characteristics of diesel spray combustion in an optically-accessible compression and expansion machine. Images of the diesel spray flame were taken by a direct photography using a CMOS camera, and the flame velocity field was estimated from the pairs of the images with an image correlation method. The velocity was separated into the high and low frequency components by a frequency separation method, and the turbulent intensity was examined. The flame temperature was determined with a two-color method in the compression and expansion machine, and the heat balance was obtained in a diesel engine with a cylinder bore and a stroke identical with the compression and expansion machine. The correlation between the turbulent properties, the flame temperature and the cooling loss was investigated while changing the fuel injection pressure.

DOI： 10.11351/jsaeronbun.50.242

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE Publications  

Thermal efficiency–related parameters in semi-premixed diesel combustion with a twin peak shaped heat release were experimentally investigated in a 0.55-L single-cylinder diesel engine. Here, the first heat release peak is realized with the premixed combustion at top dead center after the end of the first fuel injection with a sufficient ignition delay. The fuel injection quantity for the first combustion was maximized in a range to limit the rate of pressure rise below 0.6 MPa/°CA at 0.4 MPa IMEP, 0.8 MPa/°CA at 0.8 MPa IMEP, and 1.0 MPa/°CA at 1.3 MPa IMEP to ensure the large degree of constant volume heat release and to suppress smoke emissions. The second heat release peak is formed from the rate-controlled combustion with the second fuel injection immediately after the end of the first combustion. The influence of the intake oxygen concentration and the intake gas pressure on the thermal efficiency and the exhaust gas emissions was systematically examined at three load conditions (indicated mean effective pressure ≈0.4, 0.8, and 1.3 MPa). The results with two types of combustion chambers, a toroidal chamber expecting smaller cooling losses with weaker in-cylinder gas motion, and with a re-entrant chamber expecting better air utilization with stronger in-cylinder gas motion are compared. At the medium load, a significantly high indicated thermal efficiency exceeding 50% is established with a reduction in the intake oxygen concentration due to the smaller cooling loss. The indicated thermal efficiency improves with a decrease in the intake oxygen concentration as the reduction in the cooling loss is more significant than the increase in the exhaust loss. However, an excessive reduction in the intake oxygen concentration results in a deterioration in the indicated thermal efficiency due to a reduction in the combustion efficiency. At low load conditions, the indicated thermal efficiency is lower than at the medium load due to lower combustion efficiency and the improvement in the indicated thermal efficiency with reductions in the intake oxygen concentration is not significant as the combustion efficiency decreases with the decrease in the intake oxygen concentration. At the high load condition, the indicated thermal efficiency is lower due to a larger exhaust loss than at the low and medium load conditions and the indicated thermal efficiency decreases with the decrease in the intake oxygen concentration. With an increase in the intake gas pressure, the indicated thermal efficiency increases consistently mainly due to the reducing cooling loss. In comparison with the re-entrant combustion chamber, the indicated thermal efficiency with the toroidal combustion chamber is 1% higher due to a smaller cooling loss at the low load, almost comparable at the medium load and 1.2% lower at the high load due to the larger exhaust loss.

DOI： 10.1177/1468087418817967

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DOI： 10.1615/AtomizSpr.2018026468

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DOI： 10.1016/j.cattod.2018.06.023

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：自動車技術会  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：自動車技術会  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：自動車技術会  

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DOI： 10.1299/jmsesdm.2017.9.B201

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DOI： 10.1299/jmsesdm.2017.9.A311

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAE International  

Premixed diesel combustion is effective for high thermal efficiency and reductions of NOx and PM emissions, but a reduction of combustion noise is necessary for medium-high load engine operation. The control of the fuel injection has become more accurate because of the technical progress of the common rail fuel injection system, and the target heat release shape, calculated by computation, can be achieved by control of EGR, boosting, fuel injection timing, and injection quantity of multiple fuel injections. In this paper, the reduction of premixed diesel combustion noise maintaining high thermal efficiency has been investigated by the control of injection timings and heating values of multiple fuel injections. There are two aspects of the combustion noise reduction by multiple fuel injections. One is the reduction of the maximum rate of pressure rise in each combustion cycle, and the other is noise reduction effects by the noise cancelling spike (NCS) combustion. The research was conducted with both engine simulations and experiments. In combustion noise simulations, the heat release history of multiple injections was approximated by Wiebe functions and the simulated combustion noise was calculated from the fitted curve of the heat release and the coherence transfer function. The structural attenuation (SA) of the test engine was calculated from the power spectrum of the FFT analysis of the in-cylinder pressure wave data and the cross power spectrum of the sound pressure of the engine noise by the coherence method, then the combustion noise (CNL) can be calculated from the structural attenuation and cylinder pressure level (CPL) in the simulation, as shown in equation 4. The simulation results were confirmed by the engine tests. First, the combustion noise reduction by two stage fuel injection was investigated. The maximum rate of pressure rise changes depending on the combustion occurring separately in the compression and expansion strokes. One heat release was set at TDC and the second before or after the TDC. In the late two stage combustion as shown in Figure 12 (b), the combustion noise reduction was most effectively achieved when the heating value of Q2nd is higher than that of Q1st, however in the early two stage combustion in Figure 12 (a), the Q1st heat release occurs during the compression stroke and the combustion noise reduction by the early two stage NCS combustion is more effective than the combustion noise reduction by the late two stage NCS combustion. Three stage combustion simulations were also investigated at 0.6MPa IMEP and 2000 rpm. The optimum heat release shape for low combustion noise and high indicated thermal efficiency was calculated and the role of each part of the heat release in the three stage combustion is discussed. The simulation predicted 87.1 dBA of combustion noise and 50.3 % of indicated thermal efficiency. Finally, the effects of multiple fuel injections on the degree of constant volume and combustion noise are analyzed and discussed.

DOI： 10.4271/2017-01-0706

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To monitor emission-related components/systems and to evaluate the presence of malfunctioning or failures that can affect emissions, current diesel engine regulations require the use of on-board diagnostics (OBD). For diesel particulate filters (DPF), the pressure drop across the DPF is monitored by the OBD as the pressure drop is approximately linear related to the soot mass deposited in a filter. However, sudden acceleration may cause a sudden decrease in DPF pressure drop under cold start conditions. This appears to be caused by water that has condensed in the exhaust pipe, but no detailed mechanism for this decrease has been established. The present study developed an experimental apparatus that reproduces rapid increases of the exhaust gas flow under cold start conditions and enables independent control of the amount of water as well as the gas flow rate supplied to the DPF. The results show that the sudden decrease in the DPF pressure drop is caused by the water in the developed system used here. Observations of the soot cake layers in the DPF show that the decrease in the DPF pressure drop is caused by peeling-off and separation of the soot cake layer from the walls of the DPF. An increase in the water flow rate thins the soot cake layer and decreases the DPF pressure drop. Further, numerical simulation using a DPF model developed by a research group at Waseda University was also performed, and the calculated DPF pressure drop captures the changes obtained by the experiments well.

DOI： 10.4271/2017-01-2372

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n-Tridecane is a low boiling point component of gas oil, and has been used as a single-component fuel for diesel spray and combustion experiments. However, no reduced chemical kinetic mechanisms for n-tridecane have been presented for three-dimensional modeling. A detailed mechanism developed by KUCRS (Knowledge-basing Utilities for Complex Reaction Systems), contains 1493 chemical species and 3641 reactions. Reaction paths during ignition process for n-tridecane in air computed using the detailed mechanism, were analyzed with the equivalence ratio of 0.75 and the initial temperatures of 650 K, 850 K, and 1100 K, which are located in the cool-flame dominant, negative-temperature coefficient, and blue-flame dominant regions, respectively. Based on knowledge derived from the reaction path analysis, a skeletal mechanism containing 49 species and 85 reactions, was developed and validated for representing ignition characteristics over a wide range of initial conditions computed using the detailed mechanism. The skeletal mechanism includes C3H7, C2H5, and CH3 as representative fragmental alkyl radicals, C7H14, C3H6, and C2H4 as representative alkenes, and C3H7CHO and CH2O as representative aldehydes. C3-series reactions beginning with O2 addition to C3H7, were expressed using parameters for C6-series reactions, which took similar reactions for larger alkyl radicals into consideration. Ignition delay times and low-temperature oxidation induction times with the initial temperatures between 600 K and 1200 K using the skeletal mechanism, and their dependences on pressure and equivalence ratio in lean and stoichiometric cases agree well with those using the detailed mechanism. However, the agreement becomes worse as equivalence ratio is increased in rich cases.

DOI： 10.4271/2016-01-2238

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Effects of chemical reaction characteristics of premixed fuel were experimentally studied in a dual fuel compression ignition engine using port injection (PI) of gasoline-like component and direct injection (DI) of diesel fuel. Octane number of port injection fuels, direct injection timing and injection amount ratio between PI and DI were swept to assess the interaction between chemical reaction and mixture distribution in a combustion chamber. Chemical kinetic study using multi-zone modeling was also performed in order to explain experimental results under quiescent condition.

DOI： 10.4271/2015-01-1789

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Fuel design approach has been proposed as the control technique of spray and combustion processes in diesel engine to improve thermal efficiency and reduce exhaust emissions. In order to kwow if this approach is capable of controlling spray flame structure and interaction between the flame and a combustion chamber wall, the present study investigated ignition and flame characteristics of dual-component fuels, while varying mixing fraction, fuel temperature and ambient conditions. Those characteristics were evaluated through chemiluminescence photography and luminous flame photography. OH radical images and visible luminous flame images were analyzed to reveal flame shape aspect ratio and its fractal dimension.

DOI： 10.4271/2015-01-1916

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The ignition delay times of n-C₇H₁₆/O₂/N₂ and i-C₈H₁₈/O₂/N₂ mixtures with different fuel, O₂, and N₂ concentrations were calculated using a detailed chemical kinetic model generated by KUCRS. Ignition delay times with high initial temperatures, where ignition process bypasses low-temperature oxidation, were analyzed. The dependence of ignition delay time on fuel concentration, O₂ concentration, heat capacity per unit fuel concentration, and third body concentration was distilled to establish a power law equation for ignition delay time using the scaling exponents for these parameters. For n-C₇H₁₆, the scaling exponents for fuel concentration, O₂ concentration, heat capacity, and third body concentration were 0.54, 0.29, – 0.38, and 0.08, respectively, and E/R was 14400 K. For i-C₈H₁₈, the scaling exponents for fuel concentration, O₂ concentration, heat capacity, and third body concentration were 0.40, 0.76, – 0.47, and 0.00, respectively, and E/R was 11900 K.

DOI： 10.11351/jsaeronbun.46.851

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

Oil derived from Jatropha is a potential alternative to fossil fuels for Diesel engines in Mozambique because it can be cheaper and more easily available than fatty acid methyl ester, though the physical properties, e.g. high viscosity, might be a problem. As an attempt to use Jatropha oil (JO) in Diesel engines, the present study mixed JO into kerosene. Engine tests as well as un-evaporating spray visualization were carried out. The results demonstrated that a single cylinder engine can be successfully operated with JO blended kerosene despite the fact that the ignition delay is slightly longer than diesel fuel. There were no significant changes of exhaust gas emissions. It is also clear that mixing JO into kerosene can contribute to the reductions of insoluble fraction and soluble organic fraction contained in particulate matter than mixing into diesel fuel.

DOI： 10.1299/transjsme.14-00527

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Jatropha biofuel is promising renewal oil to produce biodiesel fuel through transesterification method which is shown in many papers. The ideal diesel alternative fuel obtained considering Jatropha as materials is Fatty Acid Methyl Ester (FAME). It is more desirable than the viewpoint of economical efficiency and CO&lt
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/inf&gt
control to operate a diesel engine with Jatropha crude (JC) oil. It is the purpose of this research to examine a possibility of using advantageous JC oil direct use as diesel engine fuel, in consideration of the sustainable production of the Jatropha biofuel in Mozambique. The adaptability to the diesel engine of diesel oil and the mixed fuel of JC was examined. Jatropha crude oil contains phorbol ester (PEs) which is a promoter of cancer. Measurement of the concentration of PEs in an exhaust gas was performed using High Performance Liquid Chromatography (HPLC). Skip cycle operation was performed for diesel engine with an electronically-controlled fuel injection system, and it was checked that the PEs concentration in the exhaust gas in low load operation which imitated cold starting condition. As a result of conducting the experiment by the JC mixed fuel up to JC60 had little influence on indicated thermal efficiency and the exhaust gas components except PM, and it has checked the possibility of utilization. However, PM in an exhaust gas increased in proportion to the mixed ratio of JC. Also in the skip cycle which imitated cold starting, it checked that the PEs concentration in an exhaust gas was below a detection limit.

DOI： 10.4271/2014-01-2770

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Ethanol is a promising alternative to fossil fuels because it can be made from biomass resources that are renewable. In the most cases, however, ethanol is blended with conventional fuels because of the limited amount of production. Ethanol-fuel blends are typically azeotropic and have a unique characteristic in vapor pressure and phase equilibrium, which is different from that of blends composed of simple aliphatic hydrocarbons. The current studies by the authors have developed a numerical vaporization model for ethanol-gasoline blends, which takes into account vapor-liquid equilibrium of azeotrope and high latent heat of vaporization of ethanol, in order to update the authors' multicomponent fuel spray model and to investigate effects of blending ethanol on droplet vaporization processes. In this paper, the developed vaporization model was validated through a comparison with experimentally-observed vaporization rate for single droplets of ethanol-n-heptane blends. The predicted results were in a good agreement with experimental data. The results also showed that the latent heat of vaporization of ethanol plays an important role in a droplet vaporization rate while the increase of the vapor pressure due to mixing ethanol has less effect and that consideration of the phase equilibrium composition is required to correctly predict the temporal change of the composition in a vaporizing droplet. Finally, the developed vaporization model was incorporated into authors' multicomponent fuel spray model. The effects of liquid-vapor equilibrium of ethanol-n-heptane blends and the latent heat of vaporization of ethanol were evaluated for vaporizing fuel spray.

DOI： 10.4271/2014-01-2733

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DOI： 10.11351/jsaeronbun.45.185

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The objective of this study is to understand the effect of cavitation inside the injection nozzle on spray atomization for various nozzle geometries and injection conditions. In this paper, it was focused on the influence of impulsive acceleration derived from cavitation phenomenon on liquid jet ejected from test nozzle, which was magnified 25 times based on actual nozzle size and made of acrylic for internal flow visualization. The result from this study represents that the energy spectrum of impulsive acceleration with low frequency becomes large with increase in injection pressure, and it has relationship with surface fluctuation frequency of liquid jet ejected from nozzle exit. On the other hand, it looks no distinguished difference in cavitation length and width of liquid jet with increase in dissolved air concentration in test liquid under the same injection pressure condition, whereas the energy spectrum peak appears at different frequency range among each injection or dissolved air concentration. Therefore, it concludes that the impulsive acceleration energy by cavitation bubble collapse inside the nozzle hole has less effect on width of liquid jet. © 2013 The Japan Society of Mechanical Engineers.

DOI： 10.1299/kikaib.79.2160

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Ethanol is a promising alternative to fossil fuels because it can be produced from biomass resources that are renewable. Due to the amount of production, however, the usage would be limited to blends with other conventional fuels. Ethanol-fuel blends are azeotropic and have unique vaporization characteristics different from blends composed of aliphatic hydrocarbons, so that the present study developed a numerical scheme which takes into account the vapor-liquid equilibrium of azeotrope in order to update the author's original version of the multi-component fuel CFD model and to evaluate the effect of mixing ethanol into gasoline on the evaporation process. The numerical simulation was implemented for evaporating sprays of ethanol-n-heptane blends, which are injected through a single hole nozzle. In addition to the vapor-liquid equilibrium, the effect of the latent heat of vaporization was investigated. The result clearly shows the effect of azeotropic phenomenon on the evaporation process while indicating that the latent heat of vaporization plays more significant role on the evaporation for the case of higher mixing fraction of ethanol. Copyright © 2013 SAE International and Copyright © 2013 KSAE.

DOI： 10.4271/2013-01-2552

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BEGELL HOUSE INC  

In this study, the ignition characteristics and vaporization characteristics of a dual-component mixed fuel composed of low boiling temperature (LBT) fuels were investigated experimentally in terms of fuel composition and mass fraction (Y-LBT) using a constant volume combustion vessel. For this purpose, two groups of mixed fuels were tested: The first group was a mixture of the high boiling temperature (HBT) fuel nC13 as the base fuel and various LBT fuels with similar BTs ranging from 350 to 380 K but with different ignition temperatures (ITs), and second group was a mixture of HBT fuel and various LBT fuels with ITs similar to the IT of nC13 but different BTs. The results indicate that although the type and mass fraction of the LBT fuels in the dual-component mixed fuels were varied, small changes in density did not produce changes in the spray behavior of the fuels, which is described by the spray tip penetration under the no-combustion condition. The ignition delay times for nearly all of the mixed fuels were the same as the delay time of pure nC(13) below Y-LBT = 0.5; however, the ignition delay times rapidly increased with the characteristics of the boiling curve diagrams of the mixed fuels.

DOI： 10.1615/AtomizSpr.2013007513

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Ignition, combustion and emissions characteristics of dual-component fuel spray were examined for ranges of injection timing and intake-air oxygen concentration. Fuels used were binary mixtures of gasoline-like component i-octane (cetane number 12, boiling point 372 K) and diesel fuel-like component n-tridecane (cetane number 88, boiling point 510 K). Mass fraction of i-octane was also changed as the experimental variable. The experimental study was carried out in a single cylinder compression ignition engine equipped with a common-rail injection system and an exhaust gas recirculation system. The results demonstrated that the increase of the i-octane mass fraction with optimizations of injection timing and intake oxygen concentration reduced pressure rise rate and soot and NOx emissions without deterioration of indicated thermal efficiency. Numerical investigation into the pressure rise rate reduction mechanism was also performed by use of a multi-component fuel model developed by the authors. The calculated result showed that the pressure rise rate was reduced due to the difference in the vapor concentrations between two components which have difference reactivity. © 2012 SAE Japan.

DOI： 10.4271/2012-32-0031

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DOI： 10.11351/jsaeronbun.43.875

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DOI： 10.11351/jsaeronbun.43.123

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Dual fuel operation using different reactive fuels have been examined. The present study conducted experiments in a single cylinder compression ignition engine. N-heptane (octane No.=0) and i-octane (octane No.= 100) were injected through two different injectors set at intake port and cylinder head, respectively. By comparing a case (A) in which n-heptane was directly injected into premixed charge of i-octane with a case (B) in which n-heptane was premixed and i-octane was injected into the n-heptane mixture, and by widely changing injection quantity ratio and direct injection timing, the effects of mixture concentration and combustion phasing on emissions and engine performance including thermal efficiency and maximum pressure rise rate were investigated. © 2012 The Japan Society of Mechanical Engineers.

DOI： 10.1299/kikaib.78.939

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The objective of this study is to understand the effect of cavitation inside the injection nozzle on spray atomization for various nozzle geometries and injection conditions. In this paper, pressure measurement and observation of flow pattern including cavitation inside the nozzle hole were carried out for various injection conditions and saturated vapor pressure of test fuel using by transparent nozzle which was made of acrylic and magnified 25 times. As results of these experiments, with increase in saturated vapor pressure of test fuel under the same injection pressure, cavitation develops toward the downstream of the injection nozzle hole similar to the conditions of high injection pressure with the same test fuel. The strong relationship between pressure distribution and cavitation region inside the nozzle was obtained for both experimental parameters. In addition, there was not much difference in patterns of pressure distribution and liquid jet between both experimental parameters under the same cavitation number. It is concluded that the cavitation region, pressure distribution inside the nozzle and width of liquid jet are able to be arranged by use of cavitation number. © 2012 The Japan Society of Mechanical Engineers.

DOI： 10.1299/kikaib.78.1759

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Auto-ignition and combustion processes of dual-component fuel spray were numerically studied. A source code of SUPERTRAPP (developed by NIST), which is capable of predicting thermodynamic and transportation properties of pure fluids and fluid mixtures containing up to 20 components, was incorporated into KIVA3V to provide physical fuel properties and vapor-liquid equilibrium calculations. Low temperature oxidation reaction, which is of importance in ignition process of hydrocarbon fuels, as well as negative temperature coefficient behavior was taken into account using the multistep kinetics ignition prediction based on Shell model, while a global single-step mechanism was employed to account for high temperature oxidation reaction. Computational results with the present multi-component fuel model were validated by comparing with experimental data of spray combustion obtained in a constant volume vessel. The results showed a good agreement in terms of spray tip penetration, liquid length, ignition delay and so on, for several kinds of dual-component fuels. Additional investigation into a combustion control methodology using dual-component fuel, which aims to mitigate combustion rate of premixed charge, was performed. Consequently, the feasibility of this approach was confirmed. © 2011 SAE International.

DOI： 10.4271/2011-24-0001

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In this study, it is purpose to make clear the effect of cavitation phenomenon on the spray atomization. In this report, the cavitation phenomenon inside the nozzle hole was visualized and the pressure measurements along the wall of the nozzle hole were carried out by use of 25-times enlarged acrylic nozzle. For the representatives of regular gasoline, single and two-component fuels were used as a test fuel. In addition, various cavitating flow patterns same as experimental conditions were simulated by use of Barotropic model incorporated in commercial code of Star-CD scheme, and compared with experimental results. © Copyright 2011 Society of Automotive Engineers of Japan, Inc. and SAE International.

DOI： 10.4271/2011-01-2062

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Methyl butanoate (MB) and methyl decanoate (MD) are surrogates for biodiesel fuels. According to computational results with their detailed reaction mechanisms, MB and MD indicate shorter ignition delays than long alkanes such as n-heptane and n-dodecane do at an initial temperature over 1000 K. The high ignitability of these methyl esters was computationally analyzed by means of contribution matrices proposed by some of the authors. Due to the high acidity of an α-H atom in a carbonyl compound, hydroperoxy radicals are generated out of the equilibrium between forward and backward reactions of O2 addition to methyl ester radicals by the internal transfer of an α-H atom in the initial stage of an ignition process. Some of the hydroperoxy methyl ester radicals can generate OH to activate initial reactions. MB has an efficient CH3O formation path via CH3 generated by the β-scission of an MB radical which has a radical site on the α-C atom to the carbonyl group. MB has also other CH3O formation paths via some of fragmental oxygenated radicals. Therefore, the CH3O concentration is remarkably high in a thermal ignition preparation phase. The rich CH3O decomposes into CH2O and H, and then H combines with O2 into HO2. This exothermic reaction, H + O 2 + M = HO2 + M, plays a key role in promoting initial heat release. MD has efficient paths for initial heat release starting from the O2 addition to some of fragmental methyl ester radicals and ending in the OH formation via the internal transfer of an α-H atom. These paths considerably contribute not only to promoting initial heat release but also to generating OH in the initial stage of an ignition process. In conclusion, these mechanisms for the high ignitability are caused by a common local structure of methyl ester molecules, a carbonyl group in the molecule. © Copyright 2011 Society of Automotive Engineers of Japan, Inc. and SAE International.

DOI： 10.4271/2011-01-1926

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A dual fuel operation with different reactivity fuels has the possibility of optimizing performance and emissions in premixed charge compression ignition engines by controlling the spatial concentration and distribution of both fuels. In the present study, n-heptane and i-octane were independently injected through two different injectors. In-cylinder pressure analysis and emissions measurement were performed in a compression ignition engine. Injection timings, fuel quantity ratio between the injections were changed for the two cases, in which one fuel was injected using a port fuel injection system while the other was directly injected into the cylinder, in order to drastically vary mixture distributions and ignition timings. In addition, an optical diagnostic was performed in a rapid compression and expansion machine to develop an understanding of the ignition processes of the two mixtures. The experimental results show that not only the mixedness of the more reactive fuel n-heptane but also that of the less reactive fuel i-octane have significant impacts on the ignition timings, burn rates and emissions. As a first step to establish an optimum method of controlling burn rate, engine performance and emissions formation processes, the present study developed an understanding of the effects of the mixture distributions and ignition timings of two fuels on emissions and thermal efficiency. © Copyright 2011 Society of Automotive Engineers of Japan, Inc. and SAE International.

DOI： 10.4271/2011-01-1768

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The objective of this study is to explore the relation among mixture distribution condition, chemical character of fuel, combustion processes, and emissions characteristics with premixed charge compression ignition (PCCI) operation. The present experiment employs two fuel injectors which are capable of port injection and direct one. The former was used to supply a highly-homogeneous mixture and the latter with late injection timing was employed to control the mixture heterogeneity. Thus, these sets of injection equipments are capable of setting a wide variety of mixture heterogeneity. Furthermore, two primary reference fuels were used in order to know the influences of chemical character. The experiments were conducted in order to clarify the combustion and emissions characteristics through engine tests. Optical diagnostic was also performed to gain additional insight into the combustion processes for a wide variety of mixture distribution. The results using the port injection showed that the steepness of the combustion was affected by the local equivalence ratio rather than the overall one. The double injection using both injection equipments demonstrated that the ignition source was the mixture formed by the direct injection and there was the optimum mass fraction of direct injection to reduce the maximum pressure rise rate in the case of combination of lower octane number fuel and lower compression ratio. In contrast, the different tendency was observed for the combination of higher octane number fuel and higher compression ratio. Copyright © 2009 SAE International.

DOI： 10.4271/2009-01-0498

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

It has been well-known that mixture distribution condition affects much on combustion and emissions characteristics of premixed charge compression ignition (PCCI). In response, the authors have developed a novel control technique of fuel spray characteristics utilizing flash boiling of mixed fuels in order to achieve operation range expansion and emissions reduction in the PCCI engine. To develop the effective use of them, the present study explores the relation between the mixture distribution condition, and combustion and emissions characteristics. The experiments were conducted using a single cylinder compression ignition engine and an optically accessible one, equipped with port and direct injection systems which are capable of setting a wide variety of mixture distribution condition. The results developed an understanding of the effect of the rich and lean mixture on the combustion processes and emissions. In addition, those for two primary reference fuels were compared in order to know the influences of fuel chemical character.

DOI： 10.1299/kikaib.75.759_2329

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PROFESSIONAL ENGINEERING PUBLISHING LTD  

A novel approach to reduce diesel engine emissions at relatively low injection pressures is proposed. This approach is based on the use of a mixed fuel where an additive or a low boiling point fuel such as CO(2), gas fuel, or gasoline is mixed with a higher boiling point fuel such as diesel gas oil. When producing such a fuel, the vapour-liquid equilibrium in the two-phase region where the liquid and vapour phases of both components coexist is taken into account. In designing a mixed fuel, the authors intend to control both the physical process in the spray such as fuel evaporation and vapour air mixing and the chemical processes including spontaneous ignition and with reactions with regard to NO(x), particulate matter (PM), and hydrocarbon (HC) formation. In this study flash boiling of mixed fuel is particularly focused on enhancing the mixing process in the spray because it has the potential to achieve fast evaporation and relatively lean and homogeneous mixtures. Experiments were carried out using two types of mixed fuel, both of which can generate flash boiling during injection events. In an experiment using a rapid compression machine (RCM) and an optical engine, mixed fuels consisting of liquefied CO(2) as an additive and n-tridecane representing gas oil were employed with the aim of simultaneously reducting soot and NO(x) emissions. The high-speed images acquired for sprays reacting in the RCM and the engine clearly showed a significant reduction of soot formation in the spray. Reductions of soot and NO(x) emissions as well as the fuel consumption were also confirmed by emission measurements and a combustion analysis respectively. In other experiments, different types of mixed fuel consisting of gas or gasoline and gas oil were tested to see the effects on both the evaporation and ignition processes. The result of an engine experiment showed marked reductions of soot and HC emissions and fuel consumption.

DOI： 10.1243/14680874JER02007

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DOI： 10.4271/2007-01-0624

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DOI： 10.1299/kikaib.73.1121

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A single cylinder engine has been run with direct-injection premixed charge compression ignition (PCCI) operation. The operation is fueled with primary reference fuels for a wide variety of injection timing and equivalence ratio to investigate the effect of charge stratification and octane rating on PCCI combustion. The test results showed that although the change of the injection timing can gain the high combustion efficiency for a wide range of equivalence ratio, the combustion phasing where the high combustion efficiency is accomplished is not varied only by changing the injection timings. Therefore, the only change of injection timings does not improve the thermal efficiency which is influenced by the combustion phasing. On the other hand, at the fixed compression ratio, inlet air temperature and so on, the octane rating is useful in altering the combustion phasing. The experiments in which the octane rating was changed demonstrated that for the lean air-fuel mixture which produces low NOx emission without EGR, the combustion phasing must be advanced to gain the better combustion efficiency at low load. By contrast, higher equivalence ratio allows the combustion phasing to be retarded with keeping high combustion efficiency. Copyright © 2007 SAE International.

DOI： 10.4271/2007-01-0053

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DOI： 10.1299/kikaib.72.2984

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DOI： 10.1299/kikaib.72.3113

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DOI： 10.1299/kikaib.72.1371

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The authors have explored the potential of fuel to control spray and its combustion processes in a diesel engine. Fuel has some potential for low emission and high thermal efficiency because its volatility and ignitability are one of the ultimate performing factors of the engines. In present study, the ignition process of mixed fuel spray was investigated in a constant volume combustion vessel and in a rapid compression and expansion machine, The ignition delay based on the diagram of rate of the heat release, the imaging of natural flame emissions and the numerical simulation were carried out to clarify the effect of the physical and chemical properties of mixed fuel on ignition characteristics. Copyright © 2006 SAE International.

DOI： 10.4271/2006-01-3383

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

A new primary breakup model of fuel spray with multi-component is proposed by considering the turbulent energy induced by the cavitation bubble. The model proposed here deals with bubble behavior inside nozzle, namely, the process of the growth, the shrinkage and the collapse processes are taken into account by applying Rayleigh-Plesset equation. The resultant energy contributes to the enhancement of initial perturbations on the spray surface and the perturbations grow under the action of aerodynamic force. The model proposed is implemented into KIVA-3V code in order to validate the effect of energy generated by the cavitation on the primary breakup of the discharging jet.

DOI： 10.1299/jsmemecjo.2006.3.0_329

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In this study, authors aim to convert heavy fuel or solid fuel into lighter liquid fuel with high quality and, authors propose fuel reformulation through sonochemistry and fuel design approach. Concept of Fuel design approach is to control fuel properties by mixing fuel. Its origin is Chemical-Thermodynamics and, heavy fuel converts into lighter fuel by it. The origin of sonochemistry is acoustic cavitation: creation, growth, implosive collapse of gas bubble by irradiation of high intensity ultrasonic. The sonochemical effect on organic liquid causes cleavage of C-C bond by hot spot conditions (more than 5000[K] and 100[MPa]) that are generated in collapse. In this paper, sonochemical reaction of mixing fuel was analyzed for ultrasonic of 20[kHz] and its result shows interaction of each components by fuel design approach with sonochemistry approach.

DOI： 10.1299/jsmemecjo.2006.7.0_229

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In the present study, we have proposed a novel fuel design concept in order to achieve low emissions and combustion control in diesel engine systems. According to the fuel design concept proposed in this work, the characteristics of vaporization during mixture formation process as well as of combustion can be reasonably improved due to the formation of two-phase region. Although some potential exits in this approach because spray and combustion phenomena are initiated by fuel, few studies similar to this research have been conducted. In this paper, the ignition characteristics of mixed fuel were investigated through a constant volume vessel and analysis of results shows the physical and chemical effect of each component consisted in mixed fuel on ignition processes.

DOI： 10.1299/jsmemecjo.2005.3.0_69

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We have proposed a conceptual research with fuel approach to develop understanding for potential use of fuels in terms of further improvement of thermal efficiency and exhaust emissions because they provide the significant effect on diesel engine performance. As a result, we could conclude that mixing of high volatile fuel into low volatile fuel has a possibility to control the spray and combustion processes. However, for instance, high volatility component has low ignitability, which leads to longer ignition delay, with regard to straight-chain alkane. Thus, understanding the ignition behavior of mixed fuel consisting of high and low ignitability fuels is of particular importance as ignition delay dominates the combustion process related to exhaust emissions and thermal efficiency. In this paper, an ignition experiment was conducted to investigate the ignition characteristics of mixed fuel. The experiment includes the measurement of pressure waveform and CH chemiluminescence, which indicates the onset of heat release, in order to discuss about ignition processes of mixed fuel. The results provided conclusions that the ignition of mixed fuel was initiated by high ignitability fuel and affected by volatility of high ignitability fuel.

DOI： 10.1299/jsmemecjo.2004.3.0_73

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The mixed fuel composed of two kinds of fuel oil whose boiling temperature is different each other forms the fine spray with minute droplets when its condition crosses over the two-phase region. It is expected that the fuel with low volatility dominates the ignition delay and that with high volatility does the generation of particulate matter. The experiments were carried out in a rapid compression and expansion machine and in an actual high-speed small sized diesel engine by use of this kind of fuel. The experimental results prove this expectation. Copyright © 2004 SAE International.

DOI： 10.4271/2004-01-1845

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

Original KIVA code cannot take account for the spray and combustion processes of multicomponent fuels. Therefore, it is necessary to produce the sub-models for multicomponent fuel using KIVA code. In this study, the modeling of detailed physical properties and evaporation process for multicomponent fuel was conducted. In addition, the effects of fuel composition in multicomponent fuel on vapor distribution, spray tip penetration, vapor mass and evaporation rate, and sauter mean diameter were numerically investigated by using KIVA 3V code with this multicomponent fuel spray model. From the numerical results, the spray characteristics of multicomponent fuel varied with a change in mixing fraction in multicomponent fuel. Especially, the evaporation of multicomponent fuel was not necessarily improved, even if much amount of high volatility fuel was mixed in the multicomponent fuel.

DOI： 10.1299/kikaib.70.2213

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In this study, the novel fuel design concept has been proposed in order to realize the low emission and combustion control in engine systems. In this fuel design concept, the mixed fuels with a high volatility fuel (gasoline or gaseous fuel components) and a low volatility fuel (gas oil or fuel oil components) are used in order to improve the spray characteristics by flash boiling. In our previous papers on this study, the fundamental characteristics of spray and its combustion of mixed fuel were reported. In this paper, heat release and exhaust emission (smoke, NOx and THC) characteristics of single cylinder diesel engine operated with the mixed fuels were investigated under each load. The exhaust performance of diesel engine could be improved using mixed fuel, because fuel properties and spray characteristics were controlled by changing mixing fraction of the mixed fuel. Moreover, in this exhaust gas concentration measurement, initial fuel temperature was employed for experimental parameter in order to control flash boiling process in mixed fuel spray, for flash boiling can be easily occurred by increasing initial fuel temperature. As a preliminary investigation of the flash boiling effect, the spray experiment for mixed fuel was conducted using constant volume vessel. As a result, it was confirmed that flash boiling had the potential of drastic reduction of smoke emission since flash boiling improved the atomization and vaporization of mixed fuel spray with rapid fuel-air mixing. Copyright © 2003 SAE International.

DOI： 10.4271/2003-01-1038

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Fuel design for internal combustion engines has been proposed in our study. In this concept, the multicomponent fuel with high and low volatility fuels are used in order to control the spray and combustion processes in internal combustion engine. Therefore, it is necessary to understand the spray and combustion characteristics of the multicomponent fuels in detail. In the present study, the modeling of multicomponent spray vaporization was conducted using KIVA3V code. The physical fuel properties of multicomponent fuel were estimated using the source code of NIST Mixture Property Database. Peng-Robinson equation of state and fugacity calculation were applied to the estimation of liquid-vapor equilibrium in order to take account for non-ideal vaporization process. Two-zone model in which fuel droplet was divided into droplet surface and inner core was introduced in order to simply consider the temperature distribution in fuel droplet. Furthermore, droplet diameter after breakup was optimized by changing the parameters in original TAB model, because original TAB model underestimated a droplet diameter. The effects of fuel composition and initial fuel temperature on spray tip penetration, liquid droplet and vapor distribution, vapor mass and evaporation rate were investigated by using the multicomponent fuel spray model composed of these above sub models. From the numerical results, it was confirmed that the spray characteristics of multicomponent fuel drastically varied with a change in mixing fraction in multicomponent fuel and initial fuel temperature. Copyright © 2003 Society of Automotive Engineers, Inc.

DOI： 10.4271/2003-01-1838

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Event date： 2021.9.5 - 2021.9.8

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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