著者

石田 正弘 陳 之立 植木 弘信 山田 武

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.61, no.590, pp.3518-3523, 1995-10-25 (Released:2008-03-28)

参考文献数

11

被引用文献数

1

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To reduce the level of exhaust emissions and to improve the ignition characteristics, the effect of pilot injection on combustion was examined experimentally in a turbocharged direct-injection diesel engine, and was analyzed theoretically using a two-zone combustion model. The pilot injection effect was compared with the combustion in the injection without pilot injection and also with the effect of fuel additive as an ignition improver in two kinds of fuel : high-quality fuel having a cetane index of 57 and low-quality fuel having that of 40. It is found that the pilot injection effectively reduces ignition delay at the retarded injection timing, under the low-load condition, and in the case of low-cetane fuel. The ignition delay of the main injection is reduced to about a half of that of the injection without pilot injection by the pilot injection with the short interval between pilot and main injection. The ignition delay of the low-cetane fuel is reduced to that of the high-quality fuel by a small amount of pilot injection, or by adding 1% of the ignition improver.

著者

森 賢斗 駒田 佳介 植木 弘信

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00507-16-00507, 2017 (Released:2017-06-25)

参考文献数

20

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A laser 2-focus velocimeter (L2F) was used for measurements of velocity and size of droplets in diesel fuel sprays. Diesel fuel was injected intermittently into the atmosphere by using a 8-hole injector nozzle. The diameter of the nozzle orifice was 0.112mm. The rail pressure was set at 65MPa by using a common rail system. The period of injector solenoid energizing was set at 2.3ms. The L2F had a micro-scale probe which consists of two foci. The focal diameter was about 3μm, and the distance between two foci was 20μm. The data sampling rate of the L2F system was markedly high as 15MHz. L2F measurement was conducted at 10mm downstream from the nozzle exit. Temporal and spatial changes in the velocity, size and number of droplets inside sprays were investigated. Spray images were taken by using a 180ns spark light source, and the scattered light intensity distribution and spray width were estimated. The scattered light intensity, the spray width and the number of droplets were oscillated several times in the injection period. The number of droplets at the inner region of the spray decreased and the one at the outer region of the spray increased, when the spray width increased. That is, many droplets fly to the outer region of the spray at the time when spray width is wide.

著者

山本 昌平 坂口 大作 植木 弘信 石田 正弘

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集B編 (ISSN:18848346)

巻号頁・発行日

vol.79, no.799, pp.380-389, 2013 (Released:2013-03-25)

参考文献数

16

被引用文献数

5

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In order to realize a premixed compression ignition (PCI) engine by utilizing bio-alcohol, combustion characteristics of bio-alcohol blended with gas oil were compared between ethanol and n-butanol in a diesel engine. The effects of the ethanol blend ratio and the butanol blend ratio on ignition delay, premixed combustion, diffusion combustion, fuel consumption and exhaust emissions such as smoke density, nitrogen oxide (NOx) and so on were investigated experimentally. It is found that ethanol almost burns out together with low evaporation temperature composition of gas oil in the premixed combustion period and the heat release in the diffusion combustion is based on mainly high evaporation temperature composition of gas oil, then, soot is formed in the diffusion combustion of gas oil. On the other hand, a part of butanol burns in the diffusion combustion, and the combustion of butanol in the diffusion stage is not the cause of soot formation. Butanol is more useful in diesel engine compared with ethanol because butanol can be blended with gas oil without surface-active agent, and fuel consumption and smoke are almost equal in both blend fuels if the alcohol blend ratio is the same.