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Published: September 18, 2005
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Hidenori KOSEKI
Article type: Article
Session ID: 801
Published: September 18, 2005
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This paper describes flame stability limits of low calorific gas fuel combustion for two types of fuel flow to the combustion air, one is a parallel fuel injection and another is a cross fuel supply. The experimental results showed that the blow-off stoichiometric ratios for the former are higher than those for the latter, and that the logarithmic Damkohler numbers at blow-off limit exist on one line for each fuel gas injection pattern. It was also shown that the gradient of the line for the logarithmic Damkohler numbers at blow-off limit increased with an increase in the flame stability.
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Takamichi SAITO, Chengzhen Quan, Kenji AMAGAI, Masataka ARAI
Article type: Article
Session ID: 802
Published: September 18, 2005
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Size distributions of nano-PM in diffusion flame of diesel fuel were experimentally investigated using a scanning mobility particle sizer (SMPS). Effect of lubricating oil content on PM characteristics was discussed. Concentrations of dry soot, SOF and sulfate in nano-PM were measured by a PM analyzer. Furthermore, to investigate the mechanism of PM formation in a combustion process, the distributions of polycyclic aromatic hydrocarbons (PAHs) in the flame were measured by a laser induced fluorescence (LIF) method. Also, soot distributions were measured by a laser induced incandescence (LII) method. It was found that soot and PAHs concentrations increased with increasing the lubricating oil content.
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Kousaku YOTORIYAMA, Shunsuke AMANO, Hidetomo FUJIWARA, Tomohiko FURUHA ...
Article type: Article
Session ID: 803
Published: September 18, 2005
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A new low NOx combustor for kerosene-fueled micro-gasturbine was proposed, and the combustion characteristics of prototype combustor were investigated. In order to enhance the recirculation in a primary combustion zone, a swirler was set between the primary and secondary combustion zones. Combustion air was introduced through the swirler and forced to flow upward to the combustor bottom, from where the fuel spray was supplied through a nozzle. The fundamental combustion characteristics such as lean combustion limit, flame luminosity etc. showed that this prototype combustor had a high potential for lean combustion and wide flame holding. Further, temperature distributions in the primary zone were investigated. In this report, we will clarify the characteristics of the NOx emission, propose the low NOx combustion technology for liquid fuel, and provide useful engineering guidelines for the development of the gas turbine combustor.
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Toshinaga ISHII, Satoshi TANINAKA, Yogo TAKADA, Tomoyuki WAKISAKA
Article type: Article
Session ID: 804
Published: September 18, 2005
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Recently, various mobile devices are widespread. However, these devices consume a lot of electric power. From the problem of short duration of batteries, it is required to develop small-size and light-weight fuel cells as the electric power source for them. The authors had developed a small-size and light-weight passive-type polymer electrolyte fuel cell named "Power Tube". In this study, in order to improve its performance with hydrogen as fuel, the effects of the current collector material and the cell structure on its performance were investigated. Furthermore, the generation characteristics of the cell with bio-fuel were investigated.
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Masaaki OKUYAMA, Hisanori NAKAJIMA, Toshio TOMIMURA, Ryozo ECHIGO, Yas ...
Article type: Article
Session ID: 805
Published: September 18, 2005
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An experimental study has been carried out on the synthesis of carbon nanomaterials using rice bran in methane/air laminar, fuel-rich premixed flames under atmospheric pressure. By placing a pair of porous media in the upstream and downstream sides of the combustion space, excess enthalpy burning was applied to the methane/air mixture. Rice bran was uniformly scattered on a Ni porous medium that was placed in the combustion space. Effects of the equivalence ratio and the burning velocity on nanomaterials growth have been investigated. As a result, it was found that carbon nanotubes were synthesized in non-luminous region.
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Takuji KIYA, Kazushige KIKUTA, Takemi CHIKAHISA, Yukio HISHINUMA, Kazu ...
Article type: Article
Session ID: 806
Published: September 18, 2005
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The paper investigates major parameters controlling the film deposition rate and the step coverage in batch type LPCVD devices. Based on the basic equations on the film deposition rate and by the selection of major parameters in the equations, p/u_0 parameter was estimated as the controlling parameter for both film deposition rate and step coverage at constant temperature condition. The result of the experiment agreed to the prediction in first order accuracy. The result indicates that the film deposition rate increases as the increase of the p/u_0 parameter, but it deteriorates step coverage. This implies the improvement of both deposition rate and step coverage is not accomplished by controlling pressure and flow.
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Satoshi SUMIYA, Haruo SOEDA, Junji ONISHI, Yasuhiro MASUTANI, Hiroshi ...
Article type: Article
Session ID: 807
Published: September 18, 2005
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In this paper, the results of heating and cooling examination conducted in order to investigate the thermal characteristics of Composite Materials of Microencapsulated PCM (MEPCM) and Resin, Gum, were reported. In this study, the composite materials were made by being MEPCM mixed into polyurethane resin or silicon gum. The maximum rate of MEPCM in polyurethane resin was 30wt%, on the other hand, the one of MEPCM in silicone gum of which is low coefficient of viscosity was 50wt%.
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Takahiro Ohmura, Toshio Tomimura
Article type: Article
Session ID: 808
Published: September 18, 2005
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Concerning thermal insulation of alumina silica, an empirical equation, which relates the bulk density ρ, the absolute temperature T, and the thermal conductivity of the gas λ_a to the effective thermal conductivity λ, is proposed. The effective thermal conductivity has already been shown to be composed of conduction through the solid and the gas, and further thermal radiation thorough the insulation material. In our previous study, although we have proposed the empirical equation for alumina silica insulation, the accuracy of estimation was not good at the temperature below 600℃. In this study, a more accurate empirical equation is proposed by modifying the thermal conductivity of the gas. The newly proposed empirical equation is determined using thermal conductivities measured under vacuum conditions. The values predicted by using the proposed empirical equation are shown to agree well with the measured results.
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Masahiro KIHARA, Koji MIYAZAKI, Hiroshi TSUKAMOTO
Article type: Article
Session ID: 809
Published: September 18, 2005
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Thermal radiative properties of micro-structured materials assembled with micro spherical particles of silica were investigated. Silica particles with 1, 2, and 3μm diameter were used for sample preparation. The micro-structured materials were fabricated by using colloidal technique. Micro particles formed close-packed structures self-assembly in monolayer. The spectral reflectivity was measured with Fourier Transform-Infrared Spectroscopy (FT-IR). The measured spectrum of prepared samples was evaluated by the modified Bragg's law. The micro-structured material assembled with silica spherical micro particles was anticipated for control of thermal radiative properties.
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Masamichi KOHNO, Shinji KAWAUCHI, Yasuyuki TAKATA, Takashi INOUE, Yosh ...
Article type: Article
Session ID: 810
Published: September 18, 2005
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A laser micro drilling into austenitic stainless steel (t=1mm) was performed with Bessel pulsed laser beam (532nm, pulse width 10nsec, 10Hz). The beam energy is 7mJ/pulse and the range of irradiated pulses is between 400 and 1000. The diameter and depth of the drilled holes are analyzed by SEM observation of replica sample. The diameter and depth of the hole are around 12μm and 60〜70μm, respectively. The aspect ratio doesn't change in the range of our experimental conditions. This result suggested that the laser fluenece is dominant factor of aspect ratio of the drilled holes.
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Shin-ichiro ODA, Ken-ichiro TANOUE, Tatsuo Nisimura, Kouji TAKAHASHI
Article type: Article
Session ID: 811
Published: September 18, 2005
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Chemical vapor deposition (CVD) has widely been utilized for reforming cutting-tools on a surface. CVD is a method that metal- or metallic oxide- or semiconductor- thin film is deposited on a surface of a primary material through a chemical reaction in a gas phase. There are many reports for CVD on a flat plate. However, there are few reports that investigate CVD process around objects like cutting-tools because the process involves common CVD process and furthermore complex heat- and mass- transfer around the objects. In this report, CVD process around some columnar objects in cylindrical flow channel locally heated from side wall has been studied by using 2D numerical simulation.
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Akira SAITO, Masashi MURAKAMI, Tetsuya SUMIDA, Sotoji ODAKE
Article type: Article
Session ID: 812
Published: September 18, 2005
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The fluid flow and heat transfer of the natural convection in a horizontal water layer, with heated from below and cooled from above, using water as the working fluid, were investigated experimentally. An experiment was performed for the Rayleigh number (Ra) in the range of 10^8 up to 10^<11>. The average Nusselt number was in good agreement with Globe's result. The thermal convection field in the horizontal water layer was visualized by fluorescent styrene particles and liquid crystal particles. The two-dimensional convection field was deformed to a complex structure with increasing Ra. At Ra>10^9, the three-dimensional vortex, which is new flow patterns appeared in high Rayleigh number region, was observed.
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Hiroyoshi KOIZUMI, Shinichi HANDO, Kotaro SUZUKI
Article type: Article
Session ID: 813
Published: September 18, 2005
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The aim of this basic study is to reveal the temporal and spatial heat transfer performance around an isothermally heated sphere placed in a uniform, downwardly directed flow using a micro-foil heat flow sensor, whose response time is about 0.02s. Experiments were carried out using air with a Grashof number of 3.3×10^5 and with Reynolds numbers up to 2200. Three flow patterns appeared; a chaotic flow, a steady 2-D separated flow and an unsteady 3-D separated flow. And it is also clarified that the appearance of these flow patterns and the time-averaged heat transfer performance are strongly influenced by the blockage effect. Furthermore, the wake structure of the sphere was revealed by using a hot wire anemometer and flow visualization.
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Kazuhiro ITOH, Koji SAKAMOTO, Keisuke UEOKA, Hiroshige KUMAMARU, Yutak ...
Article type: Article
Session ID: 814
Published: September 18, 2005
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Density profile in a thin thermal boundary layer arising near a rapid-heated surface was measured by using an optical technique. A 2-mm diameter stainless tube in a room temperature air environment was employed as a test section. The developed switch circuit attained a constant power density of 0.4MW/m^2 after micro-risetime (8.6-μs). The local variation of density was estimated from the displacement of fringes generated by transmitting the object wave of Mach-Zehnder interferometer through thermal boundary layer. The experimental result indicates fair agreement with the unsteady thermal conductivity equation immediately after heating. However, the discrepancy responsible for the occurrence of convection was observed with increase in heating time.
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Yasuo KOIZUMI, Hiroyasu OHTAKE, Takato SATO
Article type: Article
Session ID: 815
Published: September 18, 2005
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Pool boiling heat transfer experiments were performed by using the well-controlled/defined heat transfer surface for water. Uni-size and -shape artificial cavities were created on the mirror-finished silicon plate by utilizing the MEMS technology. Experimental results agreed well with what were predicted by the traditional boiling theory. It was confirmed experimentally that the bubble growth on the cavity and the departure were affected by neighboring cavities. The short and the long period between the departure to the successive departure alternately iterated. It suggested that the bubble departure affected by the preceding bubble and the departure not affected iterated alternately.
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Hiroyasu OHTAKE, Yasuo KOIZUMI, Ken NEMOTO
Article type: Article
Session ID: 816
Published: September 18, 2005
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Local high-heat-flux cooling by high-velocity thin-film evaporation was examined experimentally for cooling of Micro-Processor-Unit. Steady state experiments were conducted using a copper thin-film and rectangular sub-millimeter-channels. The height of the test channel was 0.5mm; the size of the heater was 2×2mm^2. The liquid velocity was about 4m/s; the liquid subcooling was 20K. Experimental results showed that the heat flux during experiment with the heating surface at exit of the test section was higher than that with the heater in the test channel. When the heater was located at the exit of the test channel, it was suppressed that a coalesced bubble extended over the whole area of the heater. Thus, the maximum heat flux (critical heat flux) was 3×10^6W/m^2 for the experiment with the heating surface at the exit of the test channel in a range of present experiments.
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Ryotaro SUZUKI, Kazunori SHINOHARA, Hiroharu KATO
Article type: Article
Session ID: 817
Published: September 18, 2005
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The effect of droplet diameter on mist cooling was examined. Using three type of nozzle, we generated three kinds of mist were 174μm, 107μm, and 34μm, respectively. The air and water flow rates were kept constant (Q_a=20l/min and Q_w=0.02l/min.) during the experiment. The air, water, mist flow were impinged vertically on the heated surface up to 600K. It was found that smaller droplets were more effective to cool down the heated surface. The effect of surface roughness was also examined.
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Nobuhiro HIMENO, Izuru OKADA
Article type: Article
Session ID: 818
Published: September 18, 2005
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An experimental study was performed on the optimum finned plate of absorption heat transfer for enhancement of steam absorption by using a downward facing plate. The heat transfer coefficient was measured for steam absorption into a LiBr aqueous solution film falling over a downward facing plate, in the case of the groove width of the finned plate being 1mm, 2mm, 3mm, 5mm, 7mm and 10mm. When the groove width is narrow, increasing viscosity effect in the groove deteriorates free convection in the liquid film; when the groove width is wide, the liquid film does not fall down uniformly over the plate. Thus the finned plate of 5mm wide groove showed the highest heat transfer coefficient in the present experiment.
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Tetsuya HIGUCHI, Yoshiyuki YAMAGUCHI
Article type: Article
Session ID: 819
Published: September 18, 2005
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Two analytic models for a water-type Stirling engine were newly developed. One is the constant temperature model, assuming the constant temperatures of working fluid, and the other is the heat transfer model, considering with the heat transfer between the heat sources and the work fluid. The constant temperature model is a conventional model for analyses of a Stirling engine. However, in an actual Stirling engine the temperatures of working fluid are not perfectly fixed, and there is few literature on a water-type Stirling engine. Therefore, these analytic models were newly developed. Using these two analytic models, influences of the resonance pipe length and the heat transfer coefficient over the performance of the engine were investigated numerically, and the tendencies in optimum values of these parameters were shown.
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Yoshiro FURUISHI, Noriyoshi DOUHARA, Syuuji NISHIDA
Article type: Article
Session ID: 820
Published: September 18, 2005
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The present study investigates a thermoacoustic Stirling cycle cooler that uses pressure fluctuation caused by thermoacoustic self-excited vibration for compression. Unlike a mechanical compressor, the thermoacoustic compressor which uses pressure fluctuation does not have a crank mechanism or a piston cylinder, and therefore requires no sealing. This is expected to remarkably improve the reliability and service life of coolers. In this system, the stack plays an important role in the thermoacoustic phenomenon. In this paper the influence of the stack material on thermoacoustic phenomenon was reported.
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Shun NIIJIMA, Kenichi SHIMIZU, Kota SHINDO, Keisuke HAMADA, Kazunori Y ...
Article type: Article
Session ID: 3101
Published: September 18, 2005
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The HCCI is a promising combustion process for simultaneously obtaining low NOx and PM emissions and high thermal efficiency. With the engine technology currently available, however, the HCCI operating region is limited and compression ignition timing is difficult to control. One side, DME has attracted interest as a potential alternative fuel for compression ignition engines. This fuel has a negative temperature coefficient region in which the ignition delay is not shortened even if the compression-induced temperature rises. DME has characteristics which is producing multi-stage heat release through both low and high temperature combustion. Based on the experimental data, this paper discusses the effect of the methane mixture on combustion in a DME fueled HCCI Engine.
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Takashi WATANABE, Yasuhiro MATSUNAGA, Takayoshi MIURA, [in Japanese], ...
Article type: Article
Session ID: 3102
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The Homogeneous Charge Compression Ignition (HCCI) engine has attracted considerable interest in recent years as a new combustion concept for internal combustion engines. The HCCI engine has three major advantages: low fuel consumption, low carbon dioxide (CO_2) emissions and low nitrogen oxide (NOx) emissions. However, the HCCI combustion process has four issues: ignition timing delay, slower combustion reaction speed (maximum heat release rate), difficulty in expanding stable operation to the high load region and avoidance of knocking. In this study, we used a primary reference fuel (40 RON) as the test fuel and tried to overcome these issues by applying internal and external exhaust gas recirculation (EGR). We varied the internal and external EGR rates and examined their respective influence on HCCI combustion.
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Seiya ENDO, Hayato MATSUNAGA, Koji YOSHIDA, Hideo SYOJI
Article type: Article
Session ID: 3103
Published: September 18, 2005
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This paper presents the results of experiments conducted with a 2-cycle engine that was the world's first such engine to comply with the emissions regulations applied to small off-road engines by the U.S. state of California in 2000. This engine is fitted with a scavenging passage that runs around the crankcase before the scavenging port. The port where air is separately inhaled is installed in this engine. The fuel blowing through is prevented by guiding and pushing the burned gas out by the air that enters from this port. The influence that causes it for the state of combustion and an exhaust gas emission is examined by changing the quantity of air for stratified scavenging device.
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Ken HASHIMOTO, Masahide MIMURA, Masataka ARAI, Tomohiko FURUHATA
Article type: Article
Session ID: 3104
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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Fundamental characteristics of six-stroke diesel engine was investigated experimentally. This engine has six processes per one cycle, i.e. intake, 1st.compression, 1st.combustion, 2nd.compression, 2nd.combustion and exhaust. By applying the direct EGR in the second combustion process, NO concentration could be reduced. However, much soot was exhausted compared with the conventional engine. To improve the fuel mixing at the second combustion process, a sub-combustion chamber, which could induce the strong combustion gas flow, was set in the engine. As the result, the NO concentration reduced drastically and soot reduced a little. Also from the measurement of PM size distribution, the particle diameter of PM generated from six-stroke engine was over 200nm, which could be trapped easily by using a diesel particulate filter.
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Takaki ITAYA, Daisuke KADOWAKI, Koji YOSHIDA, Hideo SHOJI
Article type: Article
Session ID: 3105
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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A knocking is the big factor which prevents improvement in an internal combustion engine's thermal efficiency. With the aim of understanding knocking better, light emission spectroscopy was applied in this study to examine preflame reactions that can be observed prior to autoignition. Light emission intensity was measured at wavelengths of 306.4nm (characteristic spectrum of OH), 395.2nm (HCHO). Phenomena corresponding to the passage of cool flames and blue flames and behavior indicative of a negative temperature coefficient region were observed in relation to variation of the combustion chamber inner wall temperature, ignition timing and engine speed.
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Takuro MITA, Kiyotaka SYOJI, Zhili CHEN, Mitsuru KONNO
Article type: Article
Session ID: 3106
Published: September 18, 2005
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The purpose of the study of energy accumulated type variable valve timing (EAVVT) system is to develop new valve driving technologies and provide a variable valve system for combustion control of homogenous charging compression ignition (HCCI) engines. The conceptions and principles of the system were described in this report. The test results of a prototype system indicated that the system ensures stable valve opening/closing and low energy consumption. The maximum speed seems depend upon the strength of actuator spring.
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Masanori Atarashi, Yoichi Sugihara, Mitsuru Konno, Yohji Okada, Zhili ...
Article type: Article
Session ID: 3107
Published: September 18, 2005
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Energy accumulated type variable valve timing (EAVVT) system; a new type of hydraulic valve timing system has been developed. In our study, EAVVT system was applied to a single cylinder diesel engine as a control device for homogeneous charge compression ignition (HCCI) combustion. Also, advantages of this system in HCCI combustion control were analized by numerical calculation with an elementary chemical reaction model. As a result, ignition timing was continuously controled by changing intake valve close timing.
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Yutaka MURATA, Daisuke KAWANO, Jin KUSAKA, Yasuhiro DAISHO, Hisakazu S ...
Article type: Article
Session ID: 3108
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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A variable valve timing (VVT) mechanism was applied to control premixed diesel ignition and combustion at higher load for low emissions and high thermal efficiency in a light duty diesel engine. By means of late intake valve closing, compressed gas temperature near the top dead center could be lowered, thereby increasing ignition delay to enhance fuel-air mixing. The variability of effective compression ratio has a significant potential tor controlling ignition timing of premixed charge. The VVT mechanism combined with EGR and a supercharging system could simultaneously reduce NOx, smoke and maximum combustion pressure of premixed diesel combustion at higher exhaust gas temperature.
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Katsuya SAIJYO, Kazuie NISHIWAKI
Article type: Article
Session ID: 3109
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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A PCCI combustion was simulated by the Large Eddy Simulation in conjunction with a 5-step global reaction model for hydrocarbon fuels. The PCCI combustion processes were calculated by changing engine speed and initial mean flow patterns. It is suggested that the PCCI combustion does not respond to the engine speed, and that the combustion duration can be controlled by setting tumble motion as the initial mean flow.
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Katsushige YABUKI, Shigeharu KOBORI
Article type: Article
Session ID: 3110
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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Explosion limits of DME-Air and DME-O_2 premixture is investigated experimentally using a rapid compression-expansion machine. Combustion experiments are carried out at the constant surrounding pressure with changing the compressed gas temperature at TDC. Then, representative temperature is the temperature at the center of combustion chamber measured by a thin Pt resistance wire thermometer having a diameter of 15μm. The experimental result show that explosion limits are not depended on both of equivalence ratio and compression pressure, and only depended on temperature above a pressure of 1MPa. Also, it shows that autoignition temperature of DME-Air premixture is 560K above a pressure of 1MPa.
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Toshiaki KITAGAWA, Kousaku TSUNEYOSHI
Article type: Article
Session ID: 3112
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The effects of pressure on outwardly propagating turbulent flames were studied for methane-air mixtures at the equivalence ratios from 0.8 to 1.3 and the initial pressures from 0.10 to 0.50MPa. Turbulence intensity, u' was set to 0.80 and 1.59m/s. The ratios of the turbulent burning velocities to unstretched laminar ones, u_<tn>/u_l increased as the mixture pressure increased. u_<tn>/u_l was affected by the increases in both the turbulence Reynolds number, Re and relative turbulence intensity, u'/u_l due to the mixture pressure increase. And u_<tn>/u_l increased with the decrease in the Markstein number if u'/u_l or the turbulence Reynolds number was constant. The quenching of flame kernel by the turbulence occurred for rich mixture although it did not occur for lean and stoichiometric mixtures at the same Karlovitz number, Ka. It was found to occur when the Markstein Number, Ma was large.
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Takuji ISHIYAMA, Hiroshi KAWANABE, Masahiro SHIOJI, Atsushi KOMADA, At ...
Article type: Article
Session ID: 3113
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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Optimization of fuel-air mixture strength and distribution is necessary to obtain wider operating range of natural-gas-fueled PCCI engines. From this point of view, three methods of fuel-air mixture preparation: premixed charging, direct injection and intake port injection, were compared in terms of performance, emissions and available load range. Intake port injection with variable timing offers higher engine output than premixed charging at a fixed intake charge temperature. However, the available range of fuelling rate is limited when high EGR rates or high swirl ratios are employed. Cooling effect of injected fuel should be controlled for stabilizing combustion at lean conditions.
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Hitoshi SAKURAI, Keisuke KATAHARA, Yuji YAHAGI
Article type: Article
Session ID: 3114
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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Local structures of unequal turbulent flames formed in an opposite flow have been studied experimentally for fundamental studies of the stratified combustion. Three different gas conditions, non-reacting flow, ultra lean and lean premixed reacting flow, are impinged on each other and triple boundaries which are upper and lower boundaries (UB and LB) and impinging surface (IS) are formed in the control volume. The visualized triple boundaries are taken by a laser tomography technique with a high speed camera. Time series movement, probability density function, auto correlation and cross correlation are discussed. UB, LB and IS characteristics are strongly influenced by reactive flow conditions.
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Daisei NAGAOKA, Satoshi KETADANI, Norimasa IIDA
Article type: Article
Session ID: 3115
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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Inhomogeneity of DME and air concentration affects the spatial structure of the HCCI combustion flame and characteristics of HCCI combustion. But, the effect has not been confirmed in the case using other fuels. In this study, DME and n-Butane were used as the test fuel. HCCI combustion characteristics and luminescence characteristics of high temperature reactions were investigated with the Rapid Compression Machine (RCM) using two dimensional chemiluminescence measurement to understand the relationship between combustion and chemiluminescence.
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Akihiro YAMAGUCHI, Yoshimitsu WADA, Yuji NISHIMURA, Jiro SENDA, Hajime ...
Article type: Article
Session ID: 3116
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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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.
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Tie LI, Shingo KIDO, Hideyuki OGAWA
Article type: Article
Session ID: 3117
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The dependence of ultra-high EGR and low oxygen diesel combustion on fuel properties was investigated with a single cylinder 1.0 L DI diesel engine. Decreasing cetane number in fuels significantly reduces the smoke emission due to an extension in the ignition delay and the subsequent improvement in mixture formation. Smokeless combustion, ultra-low NO_x, and efficient operation range for EGR and for IMEP are remarkably extended when decreasing the cetane number. Changes in fuel distillation temperature do not result in significant differences in the smoke emission and thermal efficiency at ultra-high EGR operation, and smokeless operation is established even with higher distillation temperature fuels when the cetane number is 40.
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Koji OSHIMA, Masakane YOSHIDA, Isamu CHIYODA, Koji IMOTO
Article type: Article
Session ID: 3118
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The deterioration of combustion and exhaust gas emissions by low cetane index fuel is being reported. Therefore this research investigated the effect of low cetane index fuel on engine performance, exhaust gas emissions, combustion characteristics and their reasons. In addition, this research sought for the improvement of combustion and exhaust gas emissions by the reduced hole diameter of injection nozzle, fuel injection timing retard and the high compression ratio with reduced cavity diameter in a piston. As a result, we could improve the trade-offs between NOx and specific fuel consumption by the above-mentioned nozzle and piston under low cetane index fuel.
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Kensuke TAKAHASHI, Hideyuki OGAWA, Yorihiro FUKUZAWA
Article type: Article
Session ID: 3119
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The effect of after-injection on exhaust gas emissions from a DI diesel engine with a common rail fuel injection system was experimentally investigated for several operating conditions varying the fuel quantities and timings of the after-injection, the EGR rates, and engine loads. Over the whole of the operating range, some reduction in smoke emissions with after-injection can be achieved without increases in other exhaust gases or reductions in thermal efficiency. The optimum quantity of after-injection for smoke reduction is 20% of total fuel supply, and the optimum timing is set just after the main injection as near as possible. The after-injection reduces smoke emissions over a wide EGR range while smoke emissions at extremely high EGR increase slightly.
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Tetsuo OHMURA, Masato IKEMOTO, Norimasa IIDA
Article type: Article
Session ID: 3120
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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For the development of a Homogeneous Charge Compression Ignition (HCCI) engine with high thermal efficiency running on DME, a control system that solves the challenges of the HCCI engine such as controlling ignition timing, the avoidance of knocking, maintaining combustion efficiency by changing the mixture fractions of the stoichiometric premixure, internal EGR gas, and external EGR gas was structured. In this paper, the influence of the mixture fraction of these three gases on HCCI combustion was investigated. As a result, by controlling the mixture fraction of EGR gas according to the changes in the amount of the stoichimetric premixture, the possibility of load control for HCCI engines with the ability to avoid knocking while maintaining a high thermal efficiency was shown.
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Yoshimitsu HARADA, Yasutaka KITAMURA, Sung-Sub KEE, Takuji ISHIYAMA, M ...
Article type: Article
Session ID: 3121
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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DI-PCCI combustion under constant volume condition was analyzed by using an ignition and combustion model employing stochastic turbulent mixing model with a reduced chemical kinetics. Calculated heat release rates showed some disagreements with the experimental data. To reveal the reason, the effect of fuel-air mixing characteristics was investigated. The results show that both turbulent integral scale and air entrainment rate affect hot flame delay and heat release rate; however, their effects depend on injection pressure.
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Masahisa YAMAKAWA, Takayoshi HAYASHI, Toshiaki NISHIMOTO, Mitsuo HITOM ...
Article type: Article
Session ID: 3122
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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An engine with DISC-HCCI hybrid combustion was designed to study the improvement of thermal efficiency in gasoline engines. The engine had both Direct Injection Stratified Charge (DISC) cylinder and Homogeneous Charge Compression Ignition (HCCI) cylinder simultaneously. The DISC cylinder was operated under Lean Burn, and then the exhaust gas was lead to the HCCI cylinder directly. Hence, it was possible for the HCCI cylinder to be operated under compression ignition easily by the high temperature exhaust gas with the left oxygen from the DISC cylinder. In this paper, the basic characteristics of the engine with DISC-HCCI hybrid combustion are described.
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Toshinari IKEGAMI, Katsuhiko YOKOTA, Tadanori Sakamaki, Sinya Ono
Article type: Article
Session ID: 3201
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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Catalysts cannot easily decompose the exhaust gas of diesel engines because of lower exhaust temperature of the engine. In this study, the decomposition of NO_x in the modulated exhaust gas was studied with plasma discharge reactor as the method. Results showed that NO in N_2 as the dilution gas could be decomposed as much as 80% by this method in an optimized condition, but the decomposition was seriously obstructed by the addition of O_2 in the gas or even NO_x was increased with the increase of O_2 concentration and plasma energy. In addition, it has been understood that the amount of NO_x reduction depends on power consumption and an initial NO level.
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Shinya TAKAKURA, Yoshinori KONDO, Yoshiyuki KIDOGUCHI, Kei MIWA
Article type: Article
Session ID: 3202
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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A study of continuous oxidation of diesel soot was carried out using a non-thermal plasma method to develop a new particulate after-treatment system. The work presented focuses on development of a high-frequency dielectric barrier discharge reactor for oxidation of NO to NO_2 in diesel exhaust and low-temperature oxidation of diesel soot with NO_2. Soot oxidation with plasma NO_2 gas begins at temperature of about 260℃ that is 100℃ lower than that of O_2. It is clear that oxidation catalyst such as hematite and palladium promote soot oxidation, and χ-alumina is effective as impregnation materials of catalyst.
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Hiroshi Amaike, Daisuke Kobayashi, Hideyuki Ogawa, Noboru Miyamoto, Ke ...
Article type: Article
Session ID: 3203
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The Characteristics of the endothermal reforming reaction between methane or propane and their burned gases modified with a mixture of steam and carbon dioxide were experimentally investigated with an heated reaction tube to develop a heat recovery system for exhaust gas of internal combustion engines. Propane reforming is more advantageous than methane reforming for a heat recovery system from exhaust gases of internal combustion engines as the reaction under low temperature conditions is more active. Further, the increase in the calorific value with propane is higher than with methane in wide temperature range. The reforming reaction improves with increases in the ratio of exhaust gas to fuel till three times the stoichiometric ratio, and further increase in the ratio of exhaust gas to fuel do not affect the reforming reaction.
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Hirotsugu HAYASHI, Yuki Kawasaki
Article type: Article
Session ID: 3204
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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In this paper, four new approximate analyses are proposed for main bearings and bearing performance such as journal orbits are compared with results by simultaneous analysis in the first paper and previous approximate method. Approximate analyses for main bearings are established.
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