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| 1.
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森田, 真一 ; 渡辺, 直樹 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Six-stroke diesel engine proposed here has six processes in one cycle, i.e. intake, 1st compression, 1st combustion, 2nd compression, 2nd combustion and exhaust. By the direct EGR in the 2nd
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combustion process, NO emission could be expected to decrease. However, much Soot was exhausted by a weak mixing in the 2nd combustion process. A high pressure injection with a common rail was introduced into the engine to improve the mixing in the second combustion process. As a result, more NO was exhausted while Soot was decreased due to better mixing. In this study, to decrease NO and Soot simultaneously, two stage fuel injection was applied to the 1st combustion. When the main injection timing for the 1st combustion process was extremely delayed, NO and Soot were decreased. It was considered that NO reduction was due to the 1st combustion of low temperature and EGR effect in the 2nd combustion. Also, Soot reduction was due to a relatively long ignition delay for the 2nd combustion
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| 2.
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星野, 浩之 ; 満山, 陽平 ; 齊藤, 正浩 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />In order to reveal the soot removal mechanism in Electric Diesel Particulate Trap (E-DPT), mechanism of soot trapping and re-burning of soot particles in exhaust gas was investigated using
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one channel electric diesel particulate trap (1 channel E-DPT). The E-DPT is capable to trap soot particles by applying DC electric field between electro-plates. The results showed that soot particles like a whisker grew up from negative electrode side toward positive one. Soot particles trapped on the plates formed many soot bridges in narrow space between electro-plates. Formation of soot particles depended on electric intensity. In the condition of F=200 kV/m, lumps of soot were observed instead of whisker like soot bridges and soot trapping and soot re-burning were balanced. Ignition of the soot lump was occurred at the contact point between the lump and electro-plate, however re-burning of whole the lump was rarely observed. Remained soot drifted to down stream. It is thought that many remained soot particles were discharged from the E-DPT. Incomplete reburning of soot lump caused soot removal efficiency deterioration of E-DPT. In the case of narrow space and high electric intensity (F=600kV/m, L=0.5mm), however, soot bridge re-burning was main phenomenon and soot lump re-burning was controlled
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| 3.
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倉持, 大輔 ; 川口, 知宏 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Ignition and combustion characteristics of diesel spray impinged on an extrude
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d wall, which was a top of cylindrical column, were experimentally investigated. Appearance positions of OH and C_2 radical luminosities and luminous flame kernel were stereoscopically observed using a two-way fiber optical system. The extruded column was fixed in a high temperature and high pressure combustion chamber. A diesel spray was impinged vertically to the extruded wall. Effects of cylindrical column diameter (D=5,10,15mm, ∞(flat wall)) on ignition and combustion characteristics were investigated. As the result, appearance position of OH luminosity was observed near the spray tip except for D=∞ (flat wall). The maximum volume of luminous flame impinged on the extruded wall was strongly influenced by the diameter of the column. In a condition of low-ambient temperature, the maximum volume of blue flame on the extruded column of 10 mm diameter was larger than those on other columns.
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| 4.
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橋本, 健 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Six-stroke diesel engine proposed here has six processes in one cycle, i.e. intaka, 1st compression, 1st combustion, 2nd compression, 2nd combustion and exhaust. By the effect of direct EGR in the
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2nd combustion process, NO concentration could be expected to decrease. However, by a weak mixing in the 2nd combustion process, much soot was exhausted and NO concentration was hardly decreased compared with the conventional four-stroke diesel engine. To improve the fuel/air mixing at the 2nd combustion process, high pressure injection with common rail system was applied to the engine. As the result, NO concentration was increased owing to the increase of premixed combustion of 1st combustion process, although soot was reduced. Therefore, the 1st injection timing was extremely advanced to control the 1st combustion process. It changed 1st combustion process into HCCI-like combustion, and NO concentration was greatly decreased. Moreover, soot was reduced with no increase of NO concentration in the 2nd combustion process. As the result, trade-off curve of NO and soot was improved compared with the conventional four-stroke diesel engine. But CO concentration was increased.
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| 5.
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川口, 知宏 ; 長瀧, 翼 ; 天谷, 賢児 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Ignition and combustion characteristics of diesel spray impinging on a wall were experimentally investigated. Ignition position and appearance position of the luminous flame
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kernel were stereoscopically observed using a two-way fiber optical system. Flat
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| 6.
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林, 義裕 ; 若林, 千裕 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Mixture formation of diesel spray impinged on an extruded surface, which was a top of cylindrical column, was investigated experimentally. A diesel spray was impinged vertically to the
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extruded surface. The behaviors of impinged spray were observed using a high-speed drum camera. A spray volume was estimated from the photographs. Effect of cylindrical column diameter on spray behavior was investigated. Adhering fuel was measured by a primitive ""wiping by paper and mass measuring"" method under various conditions. Air-fuel ratio in spray was calculated from spray volume and adhering fuel. As the result, the behavior of diesel spray impinged on an extruded column was strongly influenced by the diameter of the extruded column. From the measured results, it is clear that the air-fuel ratio in spray in the extruded column diameter of 45mm was larger than those in the other columns.
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| 7.
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ARAI, Masataka ; AMAGAI, Kenji ; NAKAJI, Takayuki ; HAYASHI, Shinji
概要:
application/pdf<br />Journal Article<br />Particulate matter (PM) emission exhausted from diesel engine should be reduced to keep the clean air environment. PM emission was considered that it consisted of coarse and
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aggregate particles, and nuclei-mode particles of which diameter was less than 50nm. However the detail characteristics about these particles of the PM were still unknown and they were needed for more physically accurate measurement and more effective reduction of exhaust PM emission. In this study, the size distributions of solid particles in PM emission were reported. PMs in the tail-pipe emission were sampled from three type diesel engines. Sampled PM was chemically treated to separate the solid carbon fraction from other fractions such as soluble organic fraction (SOF). The electron microscopic and optical-manual size measurement procedures were used to determine the size distribution of primary particles those were formed through coagulation process from nuclei-mode particles and consisted in aggregate particles. The centrifugal sedimentation method was applied to measure the Stokes diameter of dry-soot. Aerodynamic diameters of nano and aggregate particles were measured with scanning mobility particle sizer (SMPS). The peak aggregate diameters detected by SMPS were fallen in the same size regime as the Stokes diameter of dry-soot. Both of primary and Stokes diameters of dry-soot decreased with increases of engine speed and excess air ratio. Also, the effects of fuel properties and engine types on primary and aggregate particle diameters were discussed.
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| 8.
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新井, 雅隆 ; 天谷, 賢児 ; 長瀧, 翼 ; 沖田, 秀樹
概要:
application/pdf<br />Journal Article<br />Ignition and combustion characteristics of diesel spray impinging on an inclined wall were experimentally investigated. Ignition position and appearance position of the
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luminous flame kernel were stereoscopically observed using a two-way fiber optical system. Flat impingement wall was fixed in a high temperature, high pressure combustion chamber. Inclined angle of the flat wall was set at 30 degees or right angle against the center axis of the injection spray. Distance from nozzle tip to the impingement point on the wall was set at 50mm. Effect of ambient temperature on ignition position was investigated. As the result, ignition positions were observed near the spray periphery in the both cases of 30 degrees and right angle impingements. However, the luminous flame appeared near the wall surface at downword side of inclined wall because the fuel rich region was formed around the downword side of spray impingement point.
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| 9.
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林田, 守正 ; 成澤, 和幸 ; 倉嶌, 大輔 ; 紙屋, 雄史
概要:
application/pdf<br />Journal Article<br />The driving conditions of suburban transit buses were investigated with a chartered bus. Based on this data, a series hybrid system was designed for transit buses from the viewpoint of the
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acceleration performance and the energy saving. In order to measure the electric energy flow on board, the dynamometer bench tests and the static simulated experiments were carried out with storage batteries and ultra capacitors. It was clarified that the charge discharge loss in the storage devices can be estimated by the calculation using the internal resistance and current. And, the energy efficiency of the series hybrid system was evaluated in compared with conventional engine-powered buses for a trial.
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| 10.
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河野, 雅文 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Effect of cetane number on ignition delay and ignition location of disesel spray was experimentally investigated. Five kinds of fuels, which had different cetane numbers of light fraction and
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heavy fraction of fuel, were used. As a result, the ignition delay was not so affected by the change of cetane number, however, the ignition location was strongly affected by a cetane number. When the light fraction cetane number was low, the ignition was not observed near the nozzle. And when the heavy fraction cetane number was high, the ignition was observed at the position far from the nozzle. Ignition position had an effect on flame development. When the ignition occurred near the nozzle, flame development rate was slow. When the ignition occurred at the position far from the nozzle, flame development rate was fast. In case of the ignition position was far from the nozzle, effect of the cetane number on flame development was remarkable.
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