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    Effects of variable O2 concentrations and injection pressures on the combustion and emissions characteristics of the petro-diesel and hydrotreated vegetable oil-based fuels under the simulated diesel engine condition
    (2018-12-01)
    Vo, C.
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    Susumu, S.
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    Hidenori, K.
    This experimental research investigates the effects of variable O<inf>2</inf> concentrations and injection pressures on the combustion and emissions characteristics of the diesel (B7) and the hydrotreated vegetable oil (HVO)-based fuels. The O<inf>2</inf> concentrations included 21%, 15% and 10% O<inf>2</inf>, while the injection pressures were 80 and 120 MPa. The experimental fuels were the diesel fuel (B7), the neat HVO, the 20%, 50% and 80% HVO (by mass fraction) blended with the diesel. The experiments were carried out in a rapid compression-expansion machine (RCEM) under the direct injection (DI) diesel combustion condition. The analysis was undertaken using the two-color method. The experimental results indicated that the ignition delay, the heat release rate, the flame temperature, the soot density-KL factor, the NO<inf>x</inf> and soot-out emissions were inversely correlated to the HVO fraction in the blend. In addition, the findings revealed the similar flame profiles in which the higher flame temperature region and the darker KL density were concentrated around the spray flame upstream, regardless of the HVO mixing ratio. Besides, the decrease in the O<inf>2</inf> concentration resulted in the lower heat release rate, integral heat release, flame temperature, KL factor and NO<inf>x</inf> emissions but the longer ignition delay and higher soot concentration, with the highest soot concentration observed under the 15% O<inf>2</inf> environment. Nevertheless, the higher pressure differential (i.e. between the injection pressure and the ambient pressure) contributed to the shorter ignition delay, higher heat release rate, early peak of the flame temperature, wider combustion area, faster soot oxidation rate and higher NO<inf>x</inf> production.
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    WELDABILITY AND THICKNESS STUDY OF ELECTROLESS NICKEL COATING ON ALUMINIUM CONDUCTOR FOR LI-ION BATTERY PACK
    (2021-05-31)
    Chumni, N.
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    Tanprayoon, D.
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    Yenwichai, T.
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    Masomtob, M.
    Aluminium (Al) is used as an electrical conductor for battery modules to reduce the cost of battery modules but still provides high performance. An electroless nickel (EN) coating is applied to the surface of the Al conductors to meet the mentioned requirements, as it is well known in the automotive industry for its hardness and wear resistance. This paper presents a novel study on the influences of EN thickness on the weldability between the EN coated Al conductors and the tin coated copper wires using resistance spot welding (RSW). The two main parameters of this study are nickel (Ni) thickness and Al thickness. A total of twelve thickness conditions of the material are used. It consists of three differences in the thickness of Al; 2, 3 and 4 mm, that their surfaces are coated by four different thicknesses of Ni; uncoated, 10 µm, 20 µm and 30 µm. The electrical conductivity, the pull force and the peel force are measured after the specimens are welded with the tin coated copper wires. Poor and good weldabilities are studied to discover the cause of the behaviours. This study assists the primary purpose of using Al as the electrical conductor for battery modules, reducing the cost of battery modules but still offering high performance.
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    Effect of ambient temperature and density on the transition of hot temperature combustion to low temperature combustion of commercial diesel and waste plastic diesel in an optical access machine
    (2023-12-01)
    Aung, Zin Thu
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    Ewphun, Pop Paul
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    Kosaka, Hidenori
    Alternative diesel production from mixed waste plastic pyrolysis is an effective method for the management of waste plastic and its related costs. The low temperature combustion (LTC) of diesel enables the reduction of nitrogen oxides and soot simultaneously. However, because of the high quantity of unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions, LTC has a low combustion efficiency. This paper investigated the combined effect of low ambient temperature and high density (LATHD) on the transition from hot temperature combustion (HTC) to LTC by using commercial diesel (CD) and waste plastic diesel (WPD) without exhaust gas recirculation (EGR) and low cetane fuels. The results showed that NOx and soot concentrations were decreased and integral heat release was increased. For a given unit heat release, the NOx emissions of CD and WPD decreased 60% and 38%, respectively, by decreasing the ambient temperature from 1050 K to 750 K. Furthermore, integral heat release is a more influential parameter on NOx than heat release rate. After that, soot concentrations of CD and WPD were significantly decreased by 85% and 81% with a reduction in ambient temperature from 1050 K to 750 K. At the same ambient temperature, the NOx and soot concentrations of WPD were higher than that of CD for all cases. With the same ignition delay, however, the NOx and soot concentrations of WPD/high cetane fuel decreased dramatically compared to CD. This information will be useful for determining compression ratio and combustion phasing when considering engine designs.
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    Injection Characteristics of Palm Methyl Ester Blended with Diesel Using Zuech’s Chamber
    (2018-06-01)
    Srichai, Prathan
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    Ewphun, Pop Paul
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    ; ;
    Tongroon, Manida
    This research attempts to characterize the injection of palm biodiesel blended with diesel in a Zuech’s chamber. Thailand conventional diesel (mandated blend of biodiesel at 5 % or B5), palm biodiesel (B100) and four other biodiesel blends ratios (B20, B40, B60 and B80) were investigated with single hole injector of 140 and 200 μm diameters, injection pressure of 40 MPa to 160 MPa, constant back pressure of 4.5 MPa and energize time of 2.5 ms. The results show that increasing biodiesel blending ratios leads to longer injection delay, larger injection pressure drop, smaller injection quantity discharge coefficient (C<inf>d</inf>) and shorter injection duration. With increasing biodiesel blending ratio, high Cavitation number from biodiesel viscosity decreases Reynolds number. Increasing injector diameter from 140 μm to 200 μm has reduced injection delay, increased fuel injection quantity, discharge coefficient and remaining injection duration. The increasing of injection pressure were improve, injection delay, injection duration, injection quantity and discharge coefficient until injection pressure 120 MPa. In addition at injection pressure over 120 MPa are decrease injection quantity and discharge coefficient, it effect form the cavitation phenomena. Increasing of viscosity, density, Bulk modulus and sound velocity were effect to increase injection delay, with reduce injection quantity, injection duration and pressure drop during injection process.
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    EFFECT OF BIODIESEL ON COMPRESSION IGNITION ENGINE’S COMBUSTION BEHAVIOR AND PARTICLE EMISSION
    (2020-11-11)
    Tripatara, A.
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    Phairote, W.
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    Masomtob, M.
    Diesel Engines are widely known for a high compression ratio, which is proportional to the engine’s efficiency. The effect from direct injection of a diesel engine generates particulate matter (PM). PMs are mainly composed of Soot and Metallic Ash, which are harmful to human health. This research describes thermal efficiency, engine performance and combustion behavior at various load (20%, 50%, and 80%) and fuel (B7, B20, and B100) by using combustion pressure analyzer. The experimental results demonstrated that B100 has the highest ISFC and lowest ISEC for all test series owing to the highest indicated thermal efficiencies. Operating load and fuel are strongly proportional to heat release rate and ignition delay. The heat release rate of low load condition is retarded compare with medium and high load. Conventional diesel and biodiesel PMs were investigated by using Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The average size of ultrafine particles that obtained from the experiment are range of 50-500 nm and primary nanoparticle size of B7 and B100 are in range of 25-50 nm.
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    Oxidation Kinetics of Soot on Acicular Mullite Membrane Filter Using Electron Microscopy and Thermogravimetric Analysis
    (2020-12-01)
    Saenkhumvong, Eakkawut
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    ; ; ;
    Hanamura, Katsunori
    This paper investigates the oxidation kinetics of carbon black on acicular mullite using thermogravimetric (TGA) and mullite microstructures by scanning electron microscopy (SEM) for the development of diesel particulate filters (DPFs). It is observed that the amount of each chemical composition strongly affects the structure of mullite. The addition of AlF<inf>3</inf> and V<inf>2</inf>O<inf>5</inf> to mullite promotes the growth of needle-shaped mullite crystals. Thermogravimetric analysis was used to investigate and characterize chemical kinetics of soot oxidation for better understanding of designs and configurations of diesel particulate filters. The mass conversion of soot on the acicular mullite (ACM) is oxidized faster than that on the mullite (ML) membrane at all temperatures examined. The calculation of apparent activation energy (E<inf>a</inf>) of soot oxidation with isothermal methods on mullite was presented. The results showed that activation energy of soot oxidation is enhanced with ACM than with ML at all temperatures examined. The average calculated apparent activation energy of soot oxidation on ACM and ML are 146.4 kJ/mole and 155.3 kJ/mole, respectively.
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    Physicochemical Characterization of Diesel Engine’s Soot and Metal Oxide Ash Nanoparticles Using Electron Microscopy, EDS and TGA
    (2021-06-01) ; ; ;
    Chollacoop, Nuwong
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    Hanamura, Katsunori
    Physicochemical characteristics of metal oxide ash derived from engine oil additives on particulate matter (PM) from a diesel direct injection compression ignition (DDI-CI) engine, in terms of nanostructure and oxidation kinetics, were investigated through electron microscopy, energy dispersive X-ray spectroscopy and isothermal thermogravimetric analysis. Diesel and synthetic biodiesel were used as the baseline fuel. Engine performance and combustion characteristics of neat diesel and synthetic biodiesel fuel were initially reported. To enhance the formation of ash derived from lubricant additives, an accelerated ash loading method was used by dosing 10% by mass directly into the fuels. Different single primary particle nanostructures of soot and metal oxide ash were clearly observed. Single primary particle nanostructure of soot was a spherical shape composed of curve line carbon crystallites, while nanostructure of metal oxide ash was a spherically round outline shape comprised with parallel straight-line lattice fringes. Soot oxidation kinetics was significantly enhanced due to the presence of metal oxide ashes in the engine’s PM. In addition, the elemental analysis of metal oxide ash, derived from engine oil additives, was investigated using electron dispersive X-ray spectroscopy.
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    Impact of Battery Pack Shell Materials on Electrical Leakage in Submersion
    (2025-05-19)
    Ngo, D. N.
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    Kunanusont, N.
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    Meelapchotipong, P.
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    Vo, C. T.
    This study investigates the impact of battery pack shell materials on electrical leakage when fully submerged in seawater. Both conductive and insulating materials are utilized for battery pack shells. Simulations are conducted using the Finite Element Method (FEM) and are compared with experimental procedure to validate accuracy and reliability. After validation, the simulations are applied to different accident scenarios to analyze potential outcomes. The results revealed that the choice of materials significantly influences electrical leakage, as evidenced by simulations of various scenarios. Moreover, the voltage distribution changed with different battery pack shell states, indicating that the condition of the battery shell significantly impacts electrical leakage. Additionally, solutions for mitigating leakage were implemented and analyzed. Adding highly conductive materials between leaked positions can also reduce the current density in the surrounding areas. These findings are expected to provide valuable data for designing battery pack shells and enhancing the safety of electric vehicles (EVs) in potential accident scenarios.
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    Efficiency Evaluation on Cooling Behavior of Water-Cooling Jacket for Synchronous Reluctance Motor
    (2024-01-01)
    Nguyen, K. H.
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    Masomtob, M.
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    Kerdsup, B.
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    Karukanan, S.
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    Champa, P.
    This study presents the cooling efficiency after installing a water-cooling jacket for a 3-kW synchronous reluctance motor of an electric motorcycle and the factors influencing its thermal behavior by experimental and simulation approaches. The testing process was conducted as a method to collect input parameters and validate the results of the computing simulation. The simulation procedure used the step running technique to evaluate two different water-path models. The findings indicated that the maximum temperature of the stator winding and jacket cover decreased by 19.12 °C and 16.07 °C, respectively, following the installation of the water jacket and operation at a low flow rate with a current supply of 200 A. Furthermore, increasing the water flow rate leads to a substantial decrease in maximum temperature before a certain flow rate; 2 liters per minute (LPM) was chosen as the optimal rate. Temperature fluctuations exhibit an upward trend up to 1.85 °C with the higher supplied currents but drop with a higher flow rate. In addition, the motor maximum temperature in the long water-path jacket (LWJ) model was lower than in the short water-path jacket (SWJ) model due to the higher heat transfer coefficient (HTC).
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    Physicochemical characterization of direct injection Engines's soot using TEM, EDS, X-ray diffraction and TGA
    (2021-06-01)
    Oo, Hay Mon
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    ; ;
    Chollacoop, Nuwong
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    Hanamura, Katsunori
    The physical characteristics and elemental composition of particulate matters (PMs) from gasoline direct injection spark ignition (GDI-SI) engines were successfully investigated using transmission electron microscopy - energy dispersive X-ray spectroscopy (TEM-EDS). Thermogravimetric analysis (TGA) was used to analyze the PMs oxidation. The morphology of agglomerated GDI-PMs is not significantly different from the diesel direct injection compression ignition (DDI-CI) engine's PMs. The spherical single primary nanoparticles of the engine's soot composed of curve line carbon crystallites. The average diameter size of the single primary nanoparticles of GDI, DDI, and carbon black are approximately 24 nm, 26 nm, and 31 nm, while the inter-planar spacing is about 0.364 nm, 0.358 nm, and 0.356 nm, respectively. The total fringe lengths of GDI, DDI, and carbon black are approximately 154 nm, 159 nm, and 163 nm measured from the areas of 10 nm × 10 nm inner core regions of primary nanoparticles, and are 180 nm, 195 nm, and 228 nm from the outer shell regions, respectively. The total fringe lengths of inner core are shorter than the outer shell. Besides, the engine's PMs contains both crystalline and amorphous carbon structure using XRD analysis. The GDI-PMs had the least crystalline structure compared to the DDI-PMs and carbon black due to the higher percentage of amorphous fraction. TGA analysis showed that the GDI-PMs oxidation was faster than the DDI-PMs and CB-N330 oxidation because of the primary particle size, the fringe length, and the crystal size which have an impact on oxidation kinetics of particulate matters.