著者

田上 公俊 森吉 泰生 堀田 栄喜

出版者

一般社団法人 日本燃焼学会

雑誌

日本燃焼学会誌 (ISSN:13471864)

巻号頁・発行日

vol.57, no.180, pp.120-126, 2015 (Released:2018-01-26)

参考文献数

18

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Recently “plasma-assisted combustion”, especially for the use of non-equilibrium plasma for ignition has garnered interest as a new combustion technology for high efficiency and low emissions in combustors such as internal combustion engines. In this paper the focus is placed on the review of non-thermal plasma ignition and introduction of authors' recent results of this field. The ignition characteristics of non-thermal plasma are examined and compared with those of a conventional spark ignition. It is shown that a streamer discharge characterized by non-thermal plasma can ignite combustible mixtures as well as conventional thermal plasma and there are also some advantages, such as volumetric ignition and less heat loss. Through OH LIF measurement, a number of OH radical is shown to accumulate from pulse to pulse during a train of repetitive pulses, and the created radicals can initiate chemical chain reaction, which results in ignition finally.

著者

窪山 達也 森吉 泰生

出版者

一般社団法人 日本燃焼学会

雑誌

日本燃焼学会誌 (ISSN:13471864)

巻号頁・発行日

vol.58, no.183, pp.20-26, 2016 (Released:2018-01-26)

参考文献数

20

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A low speed preignition (LSPI) is one of the critical issues in recent supercharged direct injection SI gasoline engines. LSPI is strongly demanded to be solved because knocking with high intensity which is called “super-knock” or “mega-knock” follows it, and sometimes provides severe engine damage. LSPI is occasional phenomena and is often occurs in a sequential manner intermittently including normal SI combustion cycles. Though some possible sources inducing LSPI have been found and reported, chemical and physical mechanisms of LSPI phenomena have not been cleared in detail, yet. This report reviews some studies and discussed about mechanisms of LSPI in supercharged DISI engines focusing attention on the effects of lubricant oil and its additives on LSPI and the LSPI induced by hot deposit fragments detached from the wall.

著者

沈 富超 森川 弘二 森吉 泰生 窪山 達也

出版者

公益社団法人 自動車技術会

雑誌

自動車技術会論文集 (ISSN:02878321)

巻号頁・発行日

vol.51, no.3, pp.517-524, 2020 (Released:2020-05-25)

参考文献数

7

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本研究ではオイル添加剤の調整がLSPI発生頻度に与える影響を明確するため,Ca, Mg, Mo三種類の添加剤の組合せをベースに,各々の添加剤の量を2水準設定し,その組合せの計8種類の試作オイルを用意した.特にこれまでに報告例がない,IMEP 2.4MPaの超高負荷運転において,オイル添加剤がLSPI発生に与える影響を調査した.

著者

森吉 泰生

出版者

一般社団法人 日本燃焼学会

雑誌

日本燃焼学会誌 (ISSN:13471864)

巻号頁・発行日

vol.54, no.170, pp.237-242, 2012 (Released:2018-01-26)

参考文献数

14

被引用文献数

3

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Spark ignition engines are widely used for a small generator as well as a passenger vehicle. The exhaust gas emissions no longer have pollution problem by adopting a combination of three-way catalyst and stoichiometric mixture control, but an improvement of thermal efficiency is an urgent task. To achieve this, an increase of compression ratio and down-sizing with a turbo-charger are solutions. However, employing these methods causes abnormal combustion of such as knocking and pre-ignition that will bring about damages to engine components. In this article, why these phenomena occur and how to solve the issues are briefly mentioned with some author's ideas: since autoignition itself does not lead to a heavy knocking, a quick expansion at early expansion stroke and a spatial temperature distribution of mixture inside the cylinder can control the knocking intensity. As pre-ignition at low engine speed is not well analyzed, this phenomenon must be quantitatively examined.

著者

押領司 一浩 赤城 好彦 内勢 義文 周 玉宇 窪山 達也 森吉 泰生

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.84, no.863, pp.18-00002, 2018 (Released:2018-07-25)

参考文献数

8

被引用文献数

2

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To increase thermal efficiency of internal combustion engine, lean burn and EGR (Exhaust Gas Recirculation) system have been developed with spark ignition coils generating larger discharge current and discharge energy than current mass production coils. Several researches clarified that larger discharge current increases discharge channel extension and decreases possibility of discharge channel blow-off and possibility of misfire. However, these investigations don't mentioned effect of larger discharge current and energy on air-fuel ratio and combustion period. Then purpose of this research is to investigate relation among air-fuel ratio, combustion period and coil specification in order to clarify control factor of air-fuel ratio of lean burn. In this study, five coils having different current profiles were evaluated under 2000 rpm and 0.6 MPa NMEP (Net indicated Mean Effective Pressure) at lean mixture condition by combustion test and in-cylinder optical measurement test with research single cylinder engine. The combustion test results showed a correlation between lean limit air-fuel ratio and initial combustion period. Moreover, optical measurement test showed that initial combustion period has a correlation with discharge energy before 1st restrike and discharge channel extension rate and variation of initial combustion period under stable control condition doesn't depend on discharge current.