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論文
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岩崎, 浩二 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Combustion characteristics and engine performances of a swirl-chamber type IDI diesel engine using two-stage injection were experimentally investigated. The injection timing and fuel allocation ratio
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between first and second injections were widely varied. Heat release rate was analyzed to evaluate the combustion phenomena in the engine. As the result, ignition delay period for two-stage injection became longer than that for single-stage injection when the amount of fuel in the first stage injection was small. However, when the amount of fuel in the first injection was large, there was no difference of ignition delay period between two-stage injection and single-stage injection. NO and Smoke emissions and fuel consumption were improved by two-stage injection when ingition delay period became long.
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| 2.
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論文
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岩崎, 浩二 ; 荻原, 五郎 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Combustion characteristics and engine performances of a two-stage injection DI diesel engine were experimentally investigated. Two-stage injection was achieved by using two injection pumps.
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Injection timing and fuel allocation ratio between first and second injection were widely controlled. Engine performance of a two-stage injection diesel engine was compared with that of a single injection diesel engine with early timing injection. The heat release rate was analyzed to understand the combustion phenomena in a two-stage injection diesel engine. As a result, NO emission of two-stage injeciton diesel engine was improved when the first injection timing is early. The various pattern of heat release rate appeared with the change of a fuel allocation ratio. It was greatly affected by the first injection spray impinged on the cylinder wall or the piston top. The trade-off tendency between NO and smoke was influenced by the fuel allocation ratio of sub-injection pump was high.
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| 3.
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小保方, 富夫 ; 橋本, 徹 ; 五十木, 慎一 ; 柄沢, 隆夫 ; 志賀, 聖一 ; 倉林, 俊雄
概要:
application/pdf<br />Journal Article<br />The swirl and axial components of gas velocity in the disk-type combustion cha
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mber of a firing engine were measured by an LDA. The engine was operated under the conditions of a speed of 1500rpm, η_υ=0.5, φ=1.4 and ignition timing of 30°BTDC. The gas velocities at 9 points on a diameter at midheight of the combustion chamber were analyzed by the cycle-resolved method. The bulk (mean) velocity was determined by the frequency discrimination method with the cut-off frequency of 667Hz. The flame propagation pattern was detected by ionization probes set at 17 points on the piston. It has been observed that, in the case of fired operation, the turbulence intensity is higher, the integral length and micro length scales are longer and the swirl flow is weaker and is eccentrically shifted compared with the case of motored operation. These results show that it should be noted that there are remarkable differences in the gas flow between motored operation and fired opeation.
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| 4.
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論文
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志賀, 聖一 ; 江原, 秀治 ; 柄沢, 隆夫 ; 倉林, 俊雄
概要:
application/pdf<br />Journal Article<br />This paper presents one of the studies which aim to reveal the capability of controlling diesel combustion by exhaust gas recirculation (EGR). In a previous paper, the effect of EGR on soot emission
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was examined, and it was shown that soot emission is suppressed under the condition that the mass fraction burned by spontaneous (pre-mixed) combustion is increased. In a present paper, diesel knock intensity is defined as a sound pressure distributed over 1-1.5kHz, and the effect of EGR on the diesel knock intensity is examined. The diesel knock intensity is remarkably reduced by EGR under the same operating condition as soot emission is reduced by EGR. By calculating the heat release rate based on the indicated pressure diagram, it was suggested that a reduction of knock intensity originates from the reduced reaction rate in the spontaneous ignition. The quantitative relationship between the diesel knock intensity and the maximum rate of pressure rise is also presented.
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| 5.
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論文
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志賀, 聖一 ; 江原, 秀治 ; 柄沢, 隆夫 ; 倉林, 俊雄
概要:
application/pdf<br />Journal Article<br />By using a direct injection diesel engine, the effect of exhaust gas recirculation (EGR) on soot emission was investigated. It was revealed that EGR had both effects of soot promotion and
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suppression. Soot emission was suppressed when the premixed (initial rapid) combustion fraction of the two combustion patterns was increased, which was accomplished by throttling the intake valve equipped the engine or advancing the injection timing. It was also suggested that the effect of EGR on soot emission should not ascribe only the physical or thermal properties of the inert gases within the exhaust gas, but some chemical properties of CO_2. Because it was shown that only CO_2 had the effect of soot suppression under some conditions.
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