研究者詳細 - 河原　伸幸

MISC - 河原　伸幸

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第29回内燃機関シンポジウム（8.ガソリン噴霧）

河原伸幸

自動車技術会，Engine Review 9 ( 4 ) 2019年8月

８.ガソリン噴霧

河原　伸幸

Engine Review 9 ( 4 ) 32 - 33 2019年7月

光学的燃焼可視化装置による燃料噴射ノズル内部の旋回流が燃焼特性に及ぼす影響の調査

山下裕雅, 河原伸幸, 坪井和也, 冨田栄二, 藤井幹, 森中和宏

マリンエンジニアリング学術講演会講演論文集 89th 2019年

新しい計測診断技術（エンジン計測技術）

河原　伸幸

Engine Review 8 ( 3 ) 17 - 19 2018年5月

エンジン筒内の燃料濃度計測技術

河原伸幸

計測自動制御学会，「計測と制御」５月号 57 328 - 332 2018年5月

新しい計測診断技術（エンジン計測技術）

河原伸幸

自動車技術会，Engine Review 8 ( 3 ) 17 - 19 2018年5月

エンジン筒内の燃料濃度計測技術

河原　伸幸

計測と制御 57 328 - 332 2018年5月

光学的燃焼可視化装置(OCA)による極低硫黄燃料油の着火性および燃焼性の評価

窪田裕也, 冨田栄二, 河原伸幸, 坪井和也, 宮地健, 近藤守男

マリンエンジニアリング学術講演会講演論文集 88th 2018年

Visualization of combustion processes of internal combustion engines

Nobuyuki Kawahara

The Micro-World Observed by Ultra High-Speed Cameras: We See What You Don't See 261 - 275 2017年8月

記述言語：英語出版者・発行元：Springer International Publishing

Very fast visualization of fuel injection and spray impingement on the wall, the laser ignition process, and auto-ignition of the end-gas region due to flame propagation during the engine knock cycle was demonstrated using an ultra-high-speed camera for a detailed understanding of the combustion process inside an internal combustion (IC) engine. The combustion process of an IC engine is complex, involving several thermal fluid phenomena. The high-speed video camera was an essential tool for visualizing and recording these high-speed phenomena. When more magnified images are needed, the ultra-high-speed camera and a long-distance microscope with a Barlow lens were used. Here, high-speed visualization techniques were shown to understand the combustion process inside an IC engine.

DOI： 10.1007/978-3-319-61491-5_12

Multidimensional CFD simulation of diesel spray combustion using chemical kinetics

Nobuyuki Kawahara, Norihiro Takeda, Eiji Tomita

COMODIA 2017 - 9th International Conference on Modeling and Diagnostics for Advanved Engine Systems 2017年1月

Copyright © 2017 by the Japan Society of Mechanical Engineers. The purpose of this study is to simulate the process from spray injection to spray combustion in a rapid compression machine (RCM) more precisely. Spray behavior and spray combustion were simulated by Generalized Tank and Tube (GTT) code which is based on KIVA code. First, the model coefficients of modified wave break-up model for liquid droplet break-up were considered using experimental results of droplet diameter and velocity obtained using a laser 2-focus velocimeter (L2F). Calculation results of spray tip penetration under atmospheric conditions were good agreement with experimental from the visualization of isothermal spray under higher injection pressure conditions. Second, multidimensional CFD simulations of diesel spray combustion using the reduced chemical kinetics were carried out under RCM experimental conditions with 900 K of ambient temperature and 4.1 MPa of ambient pressure. The modelled results were validated by comparing predictions against corresponding experimental results in RCM. The predicted and measured in-cylinder pressure were in good agreement. Ignition process of diesel spray combustion of free spray in RCM were discussed with spray break-up phenomena, entrainment structure of higher injection pressure, and OH radical formation of diesel spray combustion.

DOI： 10.1299/jmsesdm.2017.9.B103

Chemical Kinetics and Computational Fluid-Dynamics Analysis of H2/CO/CO2/CH4 Syngas Combustion and NOx Formation in a Micro-Pilot-Ignited Supercharged Dual Fuel Engine

Nearchos Stylianidis, Ulugbek Azimov, Nobuyuki Kawahara, Eiji Tomita

SAE Technical Papers 2017- 394 - 404 2017年

記述言語：英語出版者・発行元：SAE International

A chemical kinetics and computational fluid-dynamics (CFD) analysis was performed to evaluate the combustion of syngas derived from biomass and coke-oven solid feedstock in a micro-pilot ignited supercharged dual-fuel engine under lean conditions. For this analysis, a reduced syngas chemical kinetics mechanism was constructed and validated by comparing the ignition delay and laminar flame speed data with those obtained from experiments and other detail chemical kinetics mechanisms available in the literature. The reaction sensitivity analysis was conducted for ignition delay at elevated pressures in order to identify important chemical reactions that govern the combustion process. We have confirmed the statements of other authors that HO2+OH=H2O+O2, H2O2+M=OH+OH+M and H2O2+H=H2+HO2 reactions showed very high sensitivity during high-pressure ignition delay times and had considerable uncertainty. The chemical kinetics of NOx formation was analyzed for H2/CO/CO2/CH4 syngas mixtures by using counter flow burner and premixed laminar flame speed reactor. The new mechanism showed a very good agreement with experimental measurements and accurately reproduced the effect of pressure, temperature and equivalence ratio on NOx formation. In order to identify the species important for NOx formation, a sensitivity analysis was conducted for pressures 4 bar, 10 bar and 16 bar and preheat temperature 300 K. The results show that the NOx formation is driven mostly by hydrogen based species while other species, such as N2, CO2 and CH4, have also important effects on combustion. Finally, the new mechanism was used in a multidimensional CFD simulation to predict the combustion of syngas in a micro-pilot-ignited supercharged dual-fuel engine and results were compared with experiments. The mechanism showed the closest prediction of the in-cylinder pressure and the rate of heat release (ROHR).

DOI： 10.4271/2017-24-0027

第27回内燃機関シンポジウム（点火）

自動車技術会，Engine Review 7 ( 6 ) 17 - 18 2017年

新しい計測診断技術Ⅲ（新しい流れ計測技術）

自動車技術会，Engine Review 7 ( 1 ) 14 - 15 2017年

Evaluation of Nozzle Exit Model for Transient Spray in a Multi -Hole DISI Injector

Nobuyuki Kawahara, Shuhei Takada, Eiji Tomita

19th Annual Conference of ILASS-Asia 2017年

DISIエンジンにおける燃料噴霧の壁面衝突挙動 : 表面粗さが臨界Weber数に与える影響

河原伸幸, 金高享平, 冨田栄二

微粒化シンポジウム講演論文集 25 177 - 183 2016年12月

ディーゼル噴霧燃焼の数値解析における初期条件の検討

河原伸幸, 武田規弘, 冨田栄二

微粒化シンポジウム講演論文集 25 206 - 212 2016年12月

DISIエンジンにおける燃料噴霧の壁面衝突挙動 : ノズル出口モデルおよび壁面衝突挙動の数値計算による検証

河原伸幸, 高田修坪, 冨田栄二

微粒化シンポジウム講演論文集 25 171 - 176 2016年12月

熱効率向上を指向した噴射時期と噴流形状による高圧筒内直接噴射水素エンジンの熱効率向上に関する研究

高木靖雄, 森裕樹, 中川研司, 三原雄司, 冨田栄二, 河原伸幸

自動車技術会論文集 47 ( 3 ) 705 - 710 2016年5月

DISI用インジェクタにおけるノズル出口モデルの構築

河原伸幸, 外村圭司, 冨田栄二

微粒化シンポジウム講演論文集 24 103 - 108 2015年12月

Effect of Bio-Gas Contents on SI Combustion for a Co-Generation Engine

Yungjin Kim, Nobuyuki Kawahara, Eiji Tomita, Hiroshi Oshibe, Koichi Nishikawa

SAE Technical Papers 2015- ( September ) 2015年9月

記述言語：英語出版者・発行元：SAE International

Bio-gas as an internal combustion (I.C.) engine fuel has many advantages such as cheaper fuel cost, low emission levels and especially the neutral recirculation loop of carbon dioxide, which is one of the principal factors in global warming. In this study, positive potentialities of bio-gas were investigated using a micro co-generation engine. The mixing ratio of methane (CH4) and carbon dioxide (CO2) was changed to simulate various types of bio-gases. Intake air and fuel flow rates were controlled to change the equivalence ratio. The engine load condition could be changed with the electric output power used. Base on the result, the higher CO2 content rate slowed down the engine speed in the same load condition and the combustion speed generally decreased under the same load condition with maintaining the engine speed. However thermal efficiency increased with lean burn conditions and NOX emission decreased with higher CO2 mixing rates.

DOI： 10.4271/2015-01-1946

Effect of Hydrogen Concentration on Engine Performance, Exhaust Emissions and Operation Range of PREMIER Combustion in a Dual Fuel Gas Engine Using Methane-Hydrogen Mixtures

Cagdas Aksu, Nobuyuki Kawahara, Kazuya Tsuboi, Shun Nanba, Eiji Tomita, Morio Kondo

SAE Technical Papers 2015- ( September ) 2015年9月

記述言語：英語出版者・発行元：SAE International

A single cylinder, supercharged dual fuel gas engine with micro-pilot fuel injection is operated using methane only and methane-hydrogen mixtures. Methane only experiments were performed at various equivalence ratios and equivalence ratio of 0.56 is decided as the optimum operating condition based on engine performance, exhaust emissions and operation stability. Methane-hydrogen experiments were performed at equivalence ratio of 0.56 and 2.6 kJ/cycle energy supply rate. Results show that indicated mean effective pressure is maintained regardless of hydrogen content of the gaseous fuel while thermal efficiency is improved and presence of hydrogen reduces cyclic variations. Increasing the fraction of hydrogen in the fuel mixture replaces hydrocarbon fuels and reduces carbon monoxide and hydrocarbon emissions. Mixtures with higher hydrogen content undergo faster heat release from flame propagation, approach knocking limit faster and are less knock resistant. 40% methane - 60% hydrogen mixture is prone to premature autoignition and superknocking, and is the critical concentration limit for methane-hydrogen mixtures.

DOI： 10.4271/2015-01-1792

1003 レーザ干渉法を用いた非定常ガス温度計測(燃焼・エンジンシステムI)

西村友孝, 冨田栄二, 河原伸幸

講演論文集 2015 ( 53 ) "1003 - 1"-"1003-2" 2015年2月

Experimental Study on Combustion Characteristics of Wet Ethanol Ignited by Laser-Induced Breakdown

Kazi Mostafijur Rahman, Nobuyuki Kawahara, Kazuya Tsuboi, Eiji Tomita

Proc. Of 3rd Laser Ignition Conference (Argonne, USA) 2015年1月

Effects of Bio-gas Contents on SI Combustion for a Co-generation Engine

SAE 2015 Powertrains, Fuels and Lubricants Meeting (Kyoto Japan) JSAE No.20159094/SAE 2015-01-1946 2015年

Visualization of fuel impingement on the piston top in a DISI engine

Proc. of 13th International Conference on Liquid Atomization and Spray Systems (ICLASS ) (Tainan, Taiwan) B1-1-041 2015年

ガソリン火花点火エンジンにおける火花放電挙動

河原伸幸

日本燃焼学会誌 57 ( 180 ) 106 - 111 2015年

Combustion Diagnostics Using Time-Series Analysis of Radical Emissions in a Practical Engine

21st Small Engine Technology Conference (SETC) (Osaka, Japan) 2015-32-0748 2015年

直接噴射火花点火エンジン用マルチホールインジェクタのノズル出口近傍における粒径および流速の同時計測

河原伸幸, 冨田栄二, 外村圭司

微粒化シンポジウム講演論文集 23 179 - 184 2014年12月

レーザー誘起ブレークダウン分光法のエンジン研究への適用

河原伸幸, 冨田栄二

レーザー研究 42 ( 12 ) 897 - 902 2014年

Time-series Spectra Measurements from Initial Flame Kernel in a Spark-Ignition Engine

Nobuyuki Kawahara, Atsushi Inoue, Eiji Tomita

17th International Symposium on Applications of Laser Techniques to Fluid Mechanics 1 - 7 2014年

Laser Ignition Characteristics of Hydrous Ethanol

Kazi Mostafijur Rahman, Nobuyuki Kawahara, Kazuya Tsuboi, Eiji Tomita

The 2nd Laser Ignition Conference 1 - 4 2014年

DISI用インジェクタ近傍における非定常噴霧の微粒化特性

河原伸幸, 冨田栄二, 長谷川僚

微粒化シンポジウム講演論文集 22 393 - 398 2013年12月

F071002 点火プラグ近傍燃料/CO_2濃度の同時計測(【F07100】エンジン開発に関わる最新計測・CAE技術,エンジンシステム部門企画,先端技術フォーラム)

河原伸幸

年次大会 : Mechanical Engineering Congress, Japan 2013 "F071002 - 1"-"F071002-5" 2013年9月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

In this study, simultaneous measurements of hydrocarbon fuel and carbon dioxide (CO_2) concentrations around a spark plug in the homogeneous-charge spark-ignition and the direct-injection spark-ignition engine by a spark plug sensor using infrared absorption technique were carried out. The new simultaneous measuring system including four optical fibers in an M14 spark plug was developed. It was possible that the simultaneous measurement of CO_2 and fuel concentrations in the homogeneous-charge spark-ignition combustion with methane-air or propane-air mixture. Behavior of initial flame kernel around the spark plug can be understood using hydrocarbon fuel and CO_2 concentrations around a spark plug.

1406 半導体レーザを用いた水蒸気モル吸光係数の圧力・温度依存性

河原伸幸, 冨田栄二, 家村徳彬

講演論文集 2013 ( 51 ) "1406 - 1"-"1406-2" 2013年2月

Mixing process of direct injection hydrogen jet in a constant volume vessel by using spark-induced breakdown spectroscopy

Md Tasyrif Bin Abdul Rahman, Nobuyuki Kawahara, Eiji Tomita

SAE Technical Papers 11 2013年

記述言語：英語

Hydrogen spark-ignition (SI) engines based on direct-injection (DI) have been investigated because of their potential for high thermal efficiency and solving the problems related to knocking, backfiring, and pre-ignition. Wide range flammability limits in hydrogen engine enable smooth engine operation for a very lean mixture with low NOX. However, a too lean mixture may increase ignition delay and causes severe cyclic variations. There is a possibility that the turbulence occurred during injection of fuel surround the spark plug in the combustion chamber is major contributor to this phenomenon. To overcome this problem, a better understanding of the spark discharge and spark ignition during transient hydrogen jet is necessary. Therefore, it is very important to study an effect of local equivalence ratio and behavior of spark discharge in SI engine. This paper describes a mixing process of hydrogen jet using spark-induced breakdown spectroscopy (SIBS) in a constant volume vessel. Spark discharge fluctuation images was visualized by high speed camera with the concentration measurement simultaneously. The SIBS sensor was developed from a commercial spark plug with an optical fiber embedded in the spark plug. This technique was used to detect the component of samples using the light emitted by spark-induced plasma. Spectrally resolved emission of plasma generated by the SIBS sensor was detected simultaneously by spectrometer. In this study, the strongest intensity peak of Hα(656nm) and N(501) was chosen to measure the local concentration. Comparing the intensity peaks of atomic emissions from hydrogen and nitrogen gives local hydrogen concentration in the measured volume. Copyright © 2013 SAE International and Copyright © 2013 KSAE.

DOI： 10.4271/2013-01-2526

In-cylinder observations of chemiluminescence in turbulent premixed flames using a spark plug sensor with an optical fiber

Nobuyuki Kawahara, Atsushi Inoue, Eiji Tomita

SAE Technical Papers 11 2013年

記述言語：英語

The purpose of this study was to characterize the air/fuel ratio (AFR) of turbulent premixed flames in a spark-ignition (SI) engine. We developed a spark plug sensor with an optical fiber to detect the chemiluminescence spectra, specifically the intensity of the spectral lines related to OH*, CH*, and C2* free radicals. The sensor was composed of a sapphire window and optical fiber and is applicable to automobile SI engines. Measurements of the chemiluminescence intensity from OH*, CH*, and C2* radicals were obtained in turbulent premixed flames with a propane-air mixture for different AFRs in a compression-expansion machine (CEM). The performance of the spark plug sensor was compared with a Cassegrain reflector using an intensified charge-coupled device. The results showed good agreement with measurements obtained using the Cassegrain reflector. The spark plug sensor was shown to be useful for measuring chemiluminescence of turbulent premixed flames in an SI engine. Additionally, the performance of the sensor was evaluated using a high-speed camera, and the chemiluminescence intensity was shown to be related to the time-resolved optical images. Copyright © 2013 SAE International and Copyright © 2013 KSAE.

DOI： 10.4271/2013-01-2578

軽油着火式二元燃料ガスエンジンにおける筒内燃焼の数値解析-Syngas化学反応機構のバイオガス燃焼への適用-

河副瑠惟, 河原伸幸, 冨田栄二, 坪井和也, 脇坂知行, 近藤守男

内燃機関シンポジウム講演論文集(CD-ROM) 24th 2013年

エタノール噴霧におけるレーザ着火特性

河原伸幸, 冨田栄二, 谷口陽輔

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 21 205 - 210 2012年12月

Spectrum Analysis of Chemiluminescence of a Low Sooting PCCI Diesel Engine Operating with Moderately Early Injection Timing

Robert Kiplimo, Eiji Tomita, Nobuyuki Kawahara, Sumito Yokobe, Mitsui Engineering, Shipbuilding, Co

The 8th International Conference on Modeling and Diagnostics for Advanced Engine Systems (COMODIA2012) 410 - 415 2012年12月

The spectral analysis of chemiluminescence of a PCCI diesel engine operating with moderately early injection timing was carried out in a single cylinder test engine. Investigations were conducted through direct visualization of the combustion phenomena with spectroscopic measurement of the intermediate species using a spectrometer coupled to ICCD camera. In order to understand the chemical kinetics of auto-ignition and combustion mechanism in PCCI engine, the spectral analysis of chemiluminescence was carried out. The following intermediate species were identified; OH*, CH*, CO-O recombination and formaldehyde (CH2O) which marked the different combustion phases. Formaldehyde was detected in the low temperature oxidation (LTO) region and isolated clearly by high spectral resolution. The OH* radicals marked the regions with premixed fuel-air mixtures and high temperature oxidation (HTO) region. CH* radicals were noted to mark well the fuel-rich region within the piston cavity after fuel impingement on the Derby hat wall. Soot formation arising from the fuel impingement on the Derby hat wall was oxidized in the late combustion phase. High temperature indicated by high intensity of OH* radicals led to faster oxidation of the soot in the late combustion phase. Copyright © 2012 by the Japan Society of Mechanical Engineers.

E134 レーザ干渉法を利用した非定常ガス温度計測システムの開発(OS-18: 熱・物質移動の計測および現象解析(3))

二宮仁, 冨田栄二, 河原伸幸

熱工学コンファレンス講演論文集 2012 155 - 156 2012年11月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

Laser interferometry system was developed to measure unsteady gas temperature. A 16-element photo-diode array was used as the system to detect moving direction of interference fringe more sensitively. Laser interferometry has advantage of nonintrusiveness and high-response. These advantages can improve weak point of general method such as thermistor and thermocouple. In this study, unsteady air temperature was measured by using developed system. Compared with K-type thermocouple of which wire diameter is 0.014mm, this system showed a good response. Because of high response, this system is expected to measure unsteady gas temperature in industrial field.

1416 半導体レーザ吸収法を用いた水蒸気濃度計測 :水蒸気吸収スペクトルの圧力・温度依存性(燃焼・エンジンシステムIII)

河原伸幸, 冨田栄二, 郭文驍

講演論文集 2012 ( 50 ) 141601 - 141602 2012年2月

1410 エンジンシリンダ内ガス流動に及ぼす吸気管形状の影響(燃焼・エンジンシステムII)

河原伸幸, 冨田栄二, 周世宇

講演論文集 2012 ( 50 ) 141001 - 141002 2012年2月

Effect of Spark Timing on Combustion Characteristics in a Direct-Injection Hydrogen Engine

Nobuyuki Kawahara, Mithun Kanti Roy, Takashi Fujitani, Eiji Tomita

The 8th KSME-JSME Thermal and Fluids Engineering Conference (Incheon, Korea) FR02-001 1 - 2 2012年

Combustion and Emission Characteristics of a Low Emission and Highly Efficient PCCI Diesel Engine

Robert Kiplimo, Eiji Tomita, Nobuyuki Kawahara, Sumito Yokobe, Mitsui Engineering, Shipbuilding, Co

Sustainable Research and Innovation Conference 2012 at JKUAT 1 - 7 2012年

高速度カメラを用いた噴霧現象の可視化

河原伸幸

微粒化 2012年

Simultaneous Measurement of Evaporating Droplet Diameter Using Phase Doppler Anemometry and High-speed Camera

Nobuyuki Kawahara, Eiji Tomita, Hiroya Okano

12th International Conference on Liquid Atomization and Spray Systems (ICLASS2012) 1 - 8 2012年

Low Sooting Combustion in a PCCI Diesel Engine with Moderately Early Injection Timing

Robert Kiplimo, Eiji Tomita, Nobuyuki Kawahara, Sumito Yokobe, Mitsui Engineering, Shipbuilding, Co

The 8th KSME-JSME Thermal and Fluids Engineering Conference (Incheon, Korea) FR02-001 1 - 4 2012年

Effect of Equivalence Ratio on Combustion Characteristics in a Hydrogen Direct-Injection SI Engine

Mithun Kanti Roy, Nobuyuki Kawahara, Eiji Tomita, Takashi Fujitani

4th International Conference on Sustainable Automotive Technologies (ICSAT2012) 1 - 8 2012年

High-Pressure Hydrogen Jet and Combustion Characteristics in a Direct-Injection Hydrogen Engine

Roy, M, Kawahara, N, Tomita, E, Fujitani, T

SAE International Journal of Fuels and Lubricants 5 ( 3 ) 1414 - 1425 2012年

予混合圧縮自着火機関筒内現象の数値解析(燃料噴射時期が燃焼に与える影響)

河原伸幸, 冨田栄二, 坪井和也, 高橋育子, 脇坂知行, 近藤守男

日本機械学会・自動車技術会内燃機関シンポジウム講演論文集 23rd 2012年

高速度撮影によるポート噴射インジェクタ噴霧の液滴粒径計測

河原伸幸, 冨田栄二, 植野浩平, 住田守

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 20 50 - 55 2011年12月

エンジン内燃焼火炎を見る

河原伸幸

日本機械学會誌 = Journal of the Society of Mechanical Engineers 114 ( 1114 ) 676 - 677 2011年9月

非定常噴霧におけるレーザ誘起プラズマによる着火特性

河原伸幸, 冨田栄二, 中村紳哉

微粒化 = Atomization : journal of the ILASS-Japan 20 ( 70 ) 61 - 67 2011年7月

High-pressure hydrogen jet and combustion characteristics in a direct-injection hydrogen engine

Mithun Kanti Roy, Nobuyuki Kawahara, Eiji Tomita, Takashi Fujitani

SAE Technical Papers 2011年

記述言語：英語

Hydrogen spark-ignition (SI) engines based on direct-injection (DI) promise significant advantages in terms of thermal efficiency and power output, as well as a means of overcoming problems related to knocking, backfiring, and pre-ignition. In a DI hydrogen engine, the fuel/air mixture is formed by injecting a jet of hydrogen into the air inside the combustion chamber. An Ar-ion laser beam was used as a light source to visualize the hydrogen jet in a constant-volume chamber. This allowed us to study the structure of the jet in addition to other physical processes resulting from hydrogen gas injection. Combustion experiments were conducted in a single-cylinder SI optical research engine equipped with a DI system to detect the early kernel growth assisted by the spark, as well as flame propagation. Various equivalence ratios and fuel injection timings were analyzed to identify the effects on combustion. © Copyright 2011 Society of Automotive Engineers of Japan, Inc. and SAE International.

DOI： 10.4271/2011-01-2003

Effects of injection pressure, timing and EGR on combustion and emissions characteristics of diesel PCCI engine

Robert Kiplimo, Eiji Tomita, Nobuyuki Kawahara, Shiyu Zhou, Sumito Yokobe

SAE Technical Papers 2011年

記述言語：英語

Effects of injection parameters on combustion and emission characteristics of diesel PCCI engine operating on optical and test engine was investigated. PCCI combustion was achieved through slightly narrow included angle injector, low compression ratio coupled with exhaust gas recirculation. Analysis based on diesel spray evolution, combustion process visualization and analysis was carried out. Spray penetration was evaluated and related to the exhaust emissions. Advancing the injection timing and EGR extended the ignition delay, decreased NOx emissions and increased HC, smoke and CO emissions. Higher injection pressure led to low emissions of NOx, smoke, HC and comparable CO. Optimum spray targeting position for minimum emission was identified. Impingement on the piston surface led to deterioration of emissions and increased fuel consumption while spray targeting the upper edge of Derby hat wall showed improvement in emission and engine performance. © Copyright 2011 Society of Automotive Engineers of Japan, Inc. and SAE International.

DOI： 10.4271/2011-01-1769

Ignition, combustion and exhaust emission characteristics of micro-pilot ignited dual-fuel engine operated under PREMIER combustion mode

Ulugbek Azimov, Eiji Tomita, Nobuyuki Kawahara

SAE Technical Papers 2011年

記述言語：英語

The objective of this study is to investigate the performance and emissions in a pilot-ignited supercharged dual-fuel engine, fueled with different types of gaseous fuels under various equivalence ratios. It is found that if certain operating conditions are maintained, conventional dual-fuel engine combustion mode can be transformed to the combustion mode with the two-stage heat release. This mode of combustion was called the PREMIER (PREmixed Mixture Ignition in the End-gas Region) combustion. During PREMIER combustion, initially, the combustion progresses as the premixed flame propagation and then, due to the mixture autoignition in the end-gas region, ahead of the propagating flame front, the transition occurs with the rapid increase in the heat release rate. © Copyright 2011 Society of Automotive Engineers of Japan, Inc. and SAE International.

DOI： 10.4271/2011-01-1764

バイオガスを用いた二元燃料ガスエンジン筒内燃焼の数値解析

田中雅高, 冨田栄二, 河原伸幸, 坪井和也, 脇坂知行

燃焼シンポジウム講演論文集 49th 2011年

非定常噴霧におけるレーザ誘起プラズマによる着火特性

中村紳哉, 河原伸幸, 冨田栄二

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 19 140 - 145 2010年12月

Dual PDA を用いたガソリン噴霧における非球形液滴の形状計測

岡野浩也, 河原伸幸, 冨田栄二

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 19 77 - 82 2010年12月

Visualization of Auto-Ignition of End Gas Region without Knock in a Spark-Ignition Natural Gas Engine(共著）

Eiji Tomita, Nobuyuki Kawahara, Jianjun Zheng

Journal of KONES Powertrain and Transport 17 ( 4 ) 521 - 527 2010年

点火プラグ組込型センサによる燃料濃度計測(共著）

河原伸幸, 冨田栄二

日本燃焼学会誌 52 ( 159 ) 17 - 25 2010年

点火プラグ実装型燃料・残留ガス濃度計測システム(共著）

河原伸幸, 冨田栄二

自動車技術 64 ( 2 ) 56 - 61 2010年

Effect of component of biomass-based gaseous fuels on combustion in a super-charged gas engine with micro-pilot injection(共著）

Eiji Tomita, Nobuyuki Kawahara, Murari Mohon Roy

Proceedings of Thirty-Second Task Leaders Meeting 138 - 144 2010年

Fuel Concentration Measurement of Premixed Mixture in a Spark-Ignition Engine Using Spark-Induced Breakdown Spectroscopy(共著）

Kawahara, N, Tomita, E, Oka, T, Ikeda, Y

15th Int. Symp. on Application of Laser Techniques on Fluid Mechanics 2.11.3 2010年

Residual Gas Concentration Measurement inside a Spark-ignition Engine Using Infrared Laser Absorption Method(共著）

Kawahara, N, Tomita, E, Ohtsuki, A

15th Int. Symp. on Application of Laser Techniques on Fluid Mechanics 2.8.3 2010年

Knock Characteristics and Combustion Spectroscopy in a Small Natural Gas Engine Ignited with a Pilot Injection of Gas Oil(共著）

Eiji Tomita, Nobuyuki Kawahara, Atsushi Sakane

Second International Conference of Energy Engineering (ICEE-2) 31 2010年

Visualization of Knocking Combustion in a Hydrogen Spark-Ignition Engine(共著）

Mithun Kanti Roy, Nobuyuki Kawahara, Eiji Tomita

18th World Hydrogen Energy Conference 2010 - WHEC2010 78 ( 6 ) 141 - 148 2010年

DISI用インジェクタノズル出口近傍におけるPDA計測

河原伸幸, 冨田栄二, 柴田祐一, 住田守

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 18 215 - 220 2009年12月

位相ドップラ法を用いた噴霧液滴径・速度の同時計測

河原伸幸, 冨田栄二

微粒化 = Atomization : journal of the ILASS-Japan 18 ( 63 ) 96 - 102 2009年9月

F208 Study of a Supercharged Dual-Fuel Engine Fueled by Producer Gases with Varying Injection Parameters and Hydrogen Content

Roy Murari Mohon, Tomita Eiji, Kawahara Nobuyuki, Harada Yuji, Sakane Atsushi

動力・エネルギー技術の最前線講演論文集 : シンポジウム 2009 ( 14 ) 487 - 488 2009年6月

記述言語：英語出版者・発行元：一般社団法人日本機械学会

This study investigated the effect of injection pressure and injection quantity for pilot fuel on engine performance and exhaust emissions of a supercharged producer gas-diesel dual fuel engine. Injection pressure of 80 MPa with the injection quantity of 3 mg/cycle showed the best results. Effect of hydrogen (H_2) content in producer gas on engine performance and emissions is also investigated with two types of producer gases with varying H_2 content with the optimum injection pressure-quantity condition. Experimental strategy was to optimize the injection timing for the maximization of engine power at different fuel-air equivalence ratios without knocking and within the limit of maximum cylinder pressure. Better combustion, engine performance and exhaust emissions (except NOx) are obtained with the high H_2 content producer gas than that with standard producer gas, especially at leaner conditions. Moreover, a broader window of equivalence ratio is found with highest thermal efficiencies with the high H_2 content producer gas.

412 ガソリン噴霧特性と計測技術(FM-2 噴霧燃焼過程の基礎)

河原伸幸

関西支部講演会講演論文集 2009 ( 84 ) "4 - 11" 2009年3月

413 レーザ干渉計を用いた流体温度計測(熱工学III)

冨田栄二, 河原伸幸, 山縣俊博

講演論文集 2009 ( 47 ) 119 - 120 2009年2月

808 レーザ誘起ブレイクダウン分光法によるエンジンでの空燃比計測(エンジンシステムII)

河原伸幸, 冨田栄二, 顧健

講演論文集 2009 ( 47 ) 271 - 272 2009年2月

赤外吸収法によるエンジンシリンダ内ガス濃度計測

河原伸幸, 冨田栄二

日本機械学会2009年度年次大会講演資料集 2009 181 - 182 2009年

PDA analysis near nozzle region of Transient Spray from Multi-hole Injector of DISI engine

Fatma Ahmed, Nobuyuki Kawahara, Eiji Tomita, Mamoru Sumida

The 13th Annual Conference on Liquid Atomization and Spray Systems- Asia, pp.48-55. 2009年

Microscopic Visualization of Transient Spray from Multi-hole Injector of DISI Engine

M. Esmail, N. Kawahara, E. Tomita, M.Sumida

ICLASS2009,Paper Number: 063 2009年

Mixture formation process in a spark-ignition engine with ethanol blended gasoline

Nobuyuki Kawahara, Eiji Tomita, Takuya Kadowaki

SAE Technical Papers 2009年

記述言語：英語

In this study, fuel concentration measurements in a spark-ignition (SI) engine with ethanol blended gasoline were carried out using an optical sensor installed in the spark plug with laser infrared absorption technique. The spark plug sensor for in-situ fuel concentration measurement was applied to a port injected SI engine. The molar absorption coefficients of ethanol blended gasoline were determined for various pressures and temperatures in advance using a constant volume vessel with electric heating system. Ethanol blended gasoline with high volumetric ratios shows lower molar absorption coefficients due to lower molar absorption coefficients of ethanol. The molar absorption coefficients of ethanol blended gasoline can be estimated by considering the molar fraction of each component. Mixture formation processes of ethanol blended gasoline were investigated using spark-plug sensor installed in a spark plug in a port-injected SI engine with changing the fuel injection timing in an intake port. Delaying injection of ethanol blended gasoline caused a leaner fuel concentration around the spark plug and cycle-to-cycle fluctuation of combustion. Copyright © 2009 SAE International.

DOI： 10.4271/2009-01-1957

Effect of fuel injection parameters on engine performance and emissions of a supercharged producer gas-diesel dual fuel engine

Murari Mohon Roy, Eiji Tomita, Nobuyuki Kawahara, Yuji Harada, Atsushi Sakane

SAE Technical Papers 2009年

記述言語：英語

This study investigated the effect of some pilot fuel injection parameters, like injection timing, injection pressure and injection quantity on engine performance and exhaust emissions of a supercharged producer gas-diesel dual fuel engine. The engine has been tested to be used as a co-generation engine and its power output is an important matter. Experiments have been done to optimize the injection timing, injection pressure and injection quantity for the maximization of engine power. At constant injection pressures, there is an optimum amount of pilot injection quantity for that maximum engine power is developed without knocking and within the limit of maximum cylinder pressure. Above or below of that amount engine power is decreased. Higher injection pressures generally show better results than lower ones. However, good results can also be obtained with lower injection pressure, if maximum power timings can be selected. Two-stage combustion is obtained as a mentionable fact which is an indicator of maximum power output conditions as well as a precursor of knocking combustion. Smoke is found almost zero throughout the experiments and hydrocarbons (HC) are very low. However, carbon monoxide (CO) level at all experimental conditions is very high. Nitrogen oxides (NOx) at maximum power conditions are also very high. These need to be reduced. Copyright © 2009 SAE International.

DOI： 10.4271/2009-01-1848

Effect of EGR on combustion and exhaust emissions in supercharged dual-fuel natural gas engine ignited with diesel fuel

Eiji Tomita, Yuji Harada, Nobuyuki Kawahara, Atsushi Sakane

SAE Technical Papers 2009年

記述言語：英語

The combustion and exhaust emissions characteristics of a supercharged dual-fuel natural gas engine with a single cylinder were analyzed. We focused on EGR (Exhaust Gas Recirculation) to achieve higher thermal efficiency and lower exhaust emissions. The combustion of diesel fuel (gas oil) as ignition sources was visualized using a high-speed video camera from the bottom of a quartz piston. The luminous intensity and flame decreased as the EGR rate increased. Furthermore, the ignition delay became longer due to the EGR. Characteristics of the combustion and exhaust emissions were investigated with changing EGR rates under supercharged conditions. The indicated mean effective pressure and thermal efficiency decreased with increasing EGR rate. In addition, NOx emissions decreased due to the EGR. In this study two-stage combustion was observed. When two-stage combustion occurred, it was supposed that auto-ignition of compressed natural gas and air mixture occurred during the flame development. However, knocking did not occur. Two-stage combustion occurred under the condition of low EGR rate and advanced injection timing. The indicated mean effective pressure and thermal efficiency increased, during two-stage combustion
however, NOx emissions also increased by a large amount compared to normal combustion. High indicated mean effective pressure, high thermal efficiency, and low NOx emissions were achieved just before the occurrence of two-stage combustion by changing EGR rate and injection timing of diesel fuel. Copyright © 2009 SAE International.

DOI： 10.4271/2009-01-1832

実用ガソリンインジェクタにおける微粒化過程の可視化（液糸分裂，液滴の衝突・合体挙動）

河原伸幸, 冨田栄二, 中越真一, 住田守

微粒化，Vol.18, No.62, pp.61-67. 18 ( 62 ) 61 - 67 2009年

Effect of Nozzle Geometry on Atomization of Transient Spray from Port Fuel Injector

Fatma Ahmed, Kawahara, N, Tomita, E, Sumida, M

COMODIA2008, Paper No. SC3-2, in CD-ROM 429 - 436 2008年12月

The present paper reports an experimental investigation of the effect of nozzle geometry of port fuel injector PFI on exit flow velocity, the stability of primary spray behavior and spray droplet size. Several types of PFI with were tested. The investigation of exit flow velocity and stability (wavelength) of spray structure was performed using an ultra high-speed video camera (max. camera speed 1Mfps) with a long-distance microscope (whole image). The visualized experiments were carried out in a closed chamber at the atmospheric pressure. With back-lighting, the time-series images of the spray behavior were obtained. Using ultra high-speed camera with long-distance microscope and Barlow lens, droplet diameter could be visualized with high temporal resolution (magnified image). Experimental results of average exit velocity compared with NOZZLE FLOW model where experimental results of stability and droplet diameter compared with KH-RT breakup model. Experimental investigation showed that exit velocity, droplet diameter and stability (wavelength) influence by nozzle geometry. Copyright © 2008 by the Japan Society of Mechanical Engineers.

Spray Behavior near the Nozzle of a DISI Multi-Hole Injector Using Phase Doppler Anemometer

Mohamed Esmail, Kawahara, N, Tomita, E, Sumida, M

COMODIA2008, Paper No. SC4-1, in CD-ROM 445 - 452 2008年12月

The spray from a multi-hole injector applied to direct injection spark ignition (DISI) engine was investigated. The spray has been injected into a constant volume chamber and has been visualized with a high speed video camera with a long distance microscope and quantified in terms of droplet velocity and diameter with HiDense PDA system. HiDense PDA system permits accurate measurements in spray with extremely high particle concentrations, and it is the only PDA system available that provide high quality measurements in the core region of the spray cone. The spray close to the nozzle has been investigated. Also the spray at the center axis far from the nozzle has been investigated at different injection pressure. PDA data have been processed by using a time-dividing method which divides the spray information into four distinct periods (F, C, R and T). As a result it was found that large particles ∼ (85 μm) which are injected at high speed ∼ (90 m/s) in the earliest stage lose their velocity rapidly due to breakup into smaller droplets and are overtaken by smaller but slower particles which are emitted during a later stage. The results also show that within the measured range the effect of injection pressure on droplet size was rather small. Copyright © 2008 by the Japan Society of Mechanical Engineers.

Fuel spray and its measurement techniques

Nobuyuki Kawahara, Eiji Tomita

Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy 87 897 - 902 2008年11月

In this report, fuel spray, especially engine application, and measurement techniques for fuel injection characteristics, such as break-up of liquid column, spray angle, penetration length, followability of droplets, droplet dispersion, entrainment vortex structure and so on, are explained. Microscopic visualization of liquid column break-up process in a gasoline PFI injector and simultaneous measurements of droplet diameter and velocity using phase Doppler anemometer (PDA/PDPA) are introduced as examples of measurement techniques. Obtained knowledge of spray and atomization characteristics using these techniques are mentioned in the case of unsteady spray from a gasoline injector.

軽油パイロット着火小型天然ガスエンジンのノック特性と分光計測

冨田栄二, 河原伸幸, 坂根篤

三井造船技報 ( 195 ) 41 - 47 2008年10月

軽油着火過給ガスエンジンにおけるバイオ燃料の燃焼・排気特性

冨田栄二, 河原伸幸, 薦田哲男

日本機械学會誌 = Journal of the Japan Society of Mechanical Engineers 111 ( 1076 ) 611 - 611 2008年7月

816 軽油着火過給式天然ガスエンジンにおける分光学的燃焼診断(エンジンシステムI)

冨田栄二, 河原伸幸, 久枝雄介, 薦田哲男

講演論文集 2008 ( 46 ) 309 - 310 2008年2月

超高速度カメラの応用

河原伸幸, 冨田栄二

日本機械学會誌 = Journal of the Japan Society of Mechanical Engineers 111 ( 1071 ) 120 - 123 2008年2月

Microscopic Visualization of Liquid Column Break-up Process in Gasoline PFI Injector

Kawahara, N, Tomita, E, Sumida, M

14th Int. Symp. on Application of Laser Techniques on Fluid Mechanics, Paper No. 11.2.2, in CD-rom 2008年

Visualization of Knocking Combustion in a Hydrogen Spark-Ignition Engine

Kawahara, N, Tomita, E, Yoshitomi, M

Meeting the Challenges to Sustainable Mobility 3 - 9 2008年

Fuel Concentration Measurements of Premixed Mixture Using Spark-Induced Breakdown Spectroscopy

Kawahara, N, Ikeda, Y, Tomita, E, Takemoto, S

5th International Conference on Laser-Induced Breakdown Spectroscopy (LIBS2008) 22 - 26 2008年

Effect of Gas Flow on Combustion and Exhaust Emissions in a Dual Fuel Natural Gas Engine

Tomita, E, Kawahara, N, Ohuchi, S, Komoda, T, Sakane, A

Journal of KONES Powertrain and Transport 15 ( 2 ) 519 - 527 2008年

Soot formation during knocking combustion in a spark-ignition engine

Kawahara, N, Tomita, E, Masatsuki, H

Int. Symp. on Combustion, Accepted Poster, Paper No. 1P79 2008年

Knock in a Hydrogen Spark-Ignition Engine

Kawahara, N, Tomita, E, Yoshitomi, M

Int. Symp. on Combustion, Accepted Poster, Paper No. 1P74. 2008年

Temperature Measurement of Water with a Sensor by Laser Interferometry Technique

Tomita, E, Kawahara, N

14th Int. Symp. on Application of Laser Techniques on Fluid Mechanics, Paper No. 6.3.4, in CD-rom 2008年

位相ドップラ法（PDA/PDPA）を用いた噴霧粒子径および速度の同時計測

河原伸幸, 冨田栄二

日本流体力学会誌「ながれ」 27 ( 4 ) 303 - 310 2008年

719 DISIインジェクタが形成する非定常噴霧構造の観察(エンジンシステムII,動力エネルギーシステム)

河原伸幸, 冨田栄二, 中筋寛明, 住田守

講演論文集 2007 ( 45 ) 273 - 274 2007年3月

721 層流予混合火炎のレーザ消火における数値解析(エンジンシステムII,動力エネルギーシステム)

河原伸幸, 冨田栄二, 熊谷亮佑

講演論文集 2007 ( 45 ) 277 - 278 2007年3月

718 レーザ誘起ブレイクダウン分光法によるエンジン排気ガス計測(エンジンシステムII,動力エネルギーシステム)

河原伸幸, 冨田栄二, 前原豊光, 池田裕二

講演論文集 2007 ( 45 ) 271 - 272 2007年3月

716 LIF法を用いたガスエンジン内燃料濃度分布計測(エンジンシステムI)

冨田栄二, 河原伸幸, 深谷信彦, 藤岡伸行

講演論文集 2007 ( 45 ) 267 - 268 2007年3月

計測 : レーザ誘起蛍光法

河原伸幸

微粒化 = Atomization : journal of the ILASS-Japan 15 ( 52 ) 165 - 167 2007年1月

Cycle-Resolved Measurements of the Fuel Concentration near a Spark Plug In an SI Engine Using an in-situ Laser Absorption Method

Kawahara, N, Tomita, E, Hayashi, K

6th Asia-Pacific Conference on Combustion 47 - 50 2007年1月

© 2007 Combustion Institute. All Rights Reserved. This paper describes the application of a spark plug sensor using a 3.392 μm infrared absorption technique to quantify the instantaneous gasoline concentration near the spark plug inside the engine cylinder. The mixture formation process near the spark plug in a port-injected spark-ignition (SI) engine was examined for different fuel injection timings, and determined that when the injection timing was delayed, a rich mixture remained near the top of the combustion chamber. Cyclic variations of fuel concentration at the spark timing were investigated.

Application of Laser Induced Breakdown Spectroscopy to Emission Gas Analysis of Spark Ignition Engine

Ikeda, Y, Nishiyama, A, Kaneko, M, Kawahara, N, Tomita, E

North American Symposium on Laser Induced Breakdown Spectroscopy 2007年

Combustion in a Supercharged Biomass Gas Engine with Micro-pilot Ignition- Effect of Injection Pressure and Amount of Diesel Fuel -

Tomita, E, Fukatani, N, Kawahara, N, Maruyama, K, Komoda, T

Journal of KONES Powertrain and Transport 14 ( 2 ) 513 - 520 2007年

スワールインジェクタのノズル近傍における液膜分裂過程の可視化

河原伸幸, 冨田栄二, 住田守

微粒化 16 ( 54 ) 24 - 33 2007年

Gas temperature measurement in a DME-HCCI engine using heterodyne interferometry with spark-plug-in fiber-optic sensor

Changhee Lee, Nobuyuki Kawahara, Eiji Tomita, Kenji Inoshita

SAE Technical Papers 116 ( 4 ) 316 - 324 2007年

記述言語：英語

Non-intrusive measurement of transient unburned gas temperatures was developed with a fiber-optic heterodyne interferometry system. Using the value of the Gladstone-Dale constant for DME gas and combustion pressure we can calculate the in-cylinder temperature inside unburned and burned region. In this experimental study, it was performed to set up a fiber-optic heterodyne interferometry technique to measure the temperature before and behind the combustion region in a DME-HCCI engine. At first, measured temperature was almost the same as the temperature history assuming that the process that changes of the unburned and the burned are polytropic. In addition, we measured the temperature after combustion which of condition was burned gas with DME-HCCI combustion. The developed heterodyne interferometry used the spark-plug-in fiber-optic sensor has a good feasibility to measure the unburned and burned temperature history. Copyright © 2007 Society of Automotive Engineers of Japan, Inc.

DOI： 10.4271/2007-01-1848

Residual gas fraction measurement inside engine cylinder using infrared absorption method with spark-plug sensor

Nobuyuki Kawahara, Eiji Tomita, Yutaka Tanaka

SAE Technical Papers 2007年

記述言語：英語

In this study, residual gas fraction measurements in a spark-ignition engine were carried out using an optical sensor installed in the spark plug with infrared absorption method. The residual gas fraction inside engine cylinder is proportional to the CO2 concentration. Infrared absorption method was applied and an infrared lamp and optical filter (center wavelength: around 4.3 μm) that coincides with the absorption lines of CO2 was used as a light source.The molar absorption coefficient of CO2 is discussed and compared to results in the HITRAN database. The effect of water vapor absorption doesn't affect the absorption of CO2. The absorption characteristics of CO2 were determined in advance using a constant volume vessel. Molar absorption coefficient depends on the CO2 concentration and ambient pressure and temperature, and wavelength of absorption line. Further experiments should be carried out for the quantitative measurements of CO2 concentration using infrared lamp and band-pass filter. The spark plug sensor for in-situ CO2 concentration measurement was applied to a compression-expansion machine and also to a port injected SI engine. It was possible to qualify the CO2 concentration inside residual gas during the compression stroke using the developed optical system with new spark plug sensor both in compression-expansion machine and commercial spark-ignition engine. Copyright © 2007 Society of Automotive Engineers of Japan, Inc.

DOI： 10.4271/2007-01-1849

In situ measurement of water temperature with a sensor using interferometry

Eiji Tomita

PROCEEDINGS OF THE ASME/JSME THERMAL ENGINEERING SUMMER HEAT TRANSFER CONFERENCE 2007, VOL 3 3 727 - 733 2007年

記述言語：英語出版者・発行元：AMER SOC MECHANICAL ENGINEERS

It is very important to measure fluid temperature in research and industrial fields. However, there are no devices with high-response measurement. In this study, a sensor system is proposed to measure the temperature with very high response using interferometry. The sensor for temperature measurement utilizes the difference in measurement length between two laser beams. Both are the test beams, and there is no reference beam. The two beams pass mostly through closely arranged paths; therefore, the effect of mechanical vibration on the two test beams is expected to be very small. The laser beam was introduced through a selfoc micro lens (SML) into a polarization-maintaining fiber connected with a sensor part. The beam emitted from another SML was divided into two. Both beams enter a quartz block and are reflected at the corner to change direction by an angle of a quarter pai radian. They then pass through the test section although the lengths of the two beams are different in the measurement region. This sensor was installed on a side wall of a vessel. Water was poured into the vessel and stirred with a hot magnetic stirrer. The temperature near the sensor was also measured with a thermocouple as a reference. This paper focuses on the confirmation and evaluation of this system of temperature measurement. When the direction of the fringe shift with two photo-detectors was judged, the direction of the temperature could be distinguished. One feature of this sensor is that it minimizes the effect of the thermal boundary layer. If the condition of the fluid near the test section is uniform, both beams have almost the same boundary layers. Then, both thermal boundary layers are expected to be cancelled because the length of the test section is the difference between both beams. As a result, it was confirmed that this sensor system is useful for detecting changes in water temperature.

DOI： 10.1115/HT2007-32022

Combustion Characteristics and Performance of Supercharged Pyrolysis Gas Engine with Micro-Pilot Ignition,

Tomita, E, Fukatani, N, Kawahara, N, Maruyama, K, Komoda, T

CIMAC 2007, Paper No.178. 2007年

レーザ誘起ブレイクダウン分光法によるエンジン排気ガス計測

河原伸幸, 池田裕二, 冨田栄二

東北大学金研ワークショップ 2007年

位相ドップラ法（PDA/PDPA）による噴霧粒径計測

河原伸幸, 松本雅則

第3回微粒化セミナー 45 - 58 2007年

In-situ Residual Gas Concentration Measurement near a Spark Plug In a Motorcycle SI Engine

Kawahara, N, Tomita, E, Yasuda, H

Small Engine Technology Conference 2007, SAE Paper No. 2007-32-0049 2007年

Fuel Break-up and Atomization Process near Nozzle Exit of Gasoline Injector

Kawahara, N

ILASS-Korea 2007, Invited Lecture., 3 - 8 2007年

PFIインジェクタにおける液柱分裂過程の可視化

河原伸幸

第19回内燃機関シンポジウム講演論文集, 2007-1 2007年

赤外吸収法を利用した点火プラグ実装型センサによる燃焼濃度測定 (ロータリエンジンへの適用)

河原伸幸

第19回内燃機関シンポジウム講演論文集, 2007 2007年

An aerosol nozzle that improves the spray agglomerative characteristics for optimal insecticide delivery to the target

Yuji Ikeda, Seung Mo Kim, Yoshihiro Horibe, Shigeki Takaki, Nobuyuki Kawahara

10th International Conference on Liquid Atomization and Spray Systems, ICLASS 2006 2006年12月

Spray characteristics were investigated to determine the optimum aerosol spray for insecticides while considering volatile organic carbon (VOC) reduction. Our ultimate goal is to improve the efficiency of killing insects while using less aerosol spray, which contains chemicals, oil, and dimethyl ether (DME). Most of the oil and propellant fail to reach the target, and fall to the ground. The propellant is used to break droplets into smaller droplets and to carry them to the target. Most of the propellant's energy is used for carrying these droplets, although the remaining droplets are very small compared to those produced at the nozzle. We investigated the droplet characteristics over the entire distance from the nozzle to the target. Here, we tested different nozzle dimensions and compared single- and double-hole nozzles. We measured the spray characteristics near the nozzle to evaluate the droplet-forming process by examining droplet separation, agglomeration, collision, and size to elucidate the spray behavior and determine the dominant factors involved in designing and developing a nozzle for spraying insecticides most effectively. The key factor for developing the optimum nozzle for spraying insecticides is not the number of holes or nozzle diameter, but the agglomeration process and the amount at the target distance. The key to developing a system that decreases VOC dramatically is how the droplets are generated at the nozzle. Droplet diameter and velocity when exiting the nozzle need to be understood quantitatively and controlled; the most important considerations are to maximize spray agglomeration, in order to deliver droplets with an effective diameter to the target, and to reduce the number of oversized droplets failing to reach the target.

PDA measurement of transient spray formed by a DISI multi-hole injector

Kawahara, N, Tomita, E, Nakasuji, H, Sumida, M

ICLASS2006, 2006年12月

The droplet characteristics of unsteady fuel spray formed by multi-hole injector used in direct injection gasoline engine was investigated. In order to understand the detail structure of transient spray, a phase Doppler anemometer was used. The traverse system of the vessel was designed to obtain two-dimensional structure of spray. The laser power at measurement volume was optimized in order to detect relative smaller droplets. It is necessary to evaluate the effect of laser power of measurement volume on detection limit of smaller droplets under 10 μm. Phase locking method was used to analyze ensemble mean value of axial/radial droplet velocity, axial/radial slip velocity, relative droplet Reynolds number, and droplet turbulent kinetic energy. As a result, smaller droplets under 10 μm can follow the entrainment vortex at the spray shell. On the other hand, larger droplets over 30 μm have larger velocity to penetrate the entrainment vortex. Intermediate droplets of 15<D≦ 20μm in diameter are criteria for follow/penetration of vortex.

Spatial and Temporal Characteristics of Laser-induced Air Plasma

Kawahara, N. Tomita, E. Nakayama, T. Ikeda, Y. Nishiyama, A

44th AIAA Aerospace Sciences Meeting and Exhibit, 23 17586 - 17595 2006年12月

We investigated laser-induced breakdown in air using a framing intensified charged coupled device (ICCD) camera and fiber-coupled ICCD spectrometer with Cassegrain optics. Localized breakdown plasma was generated from the laser pulse of a Q-switched Nd:YAG laser with a wavelength of 532 nm, and we obtained the temporal evolution of the air plasma shape, size, and location. During the initial stage, breakdown occurred on the laser side of the focal point due to the absorption of the pulse energy. Then, the breakdown plasma generally propagated in the direction of the laser. The propagation speed of the laserinduced breakdown was estimated to exceed 10 km/s during the initial stage of breakdown. The high spatial resolution of the Cassegrain optics system was used to observe different ionization levels in the breakdown plasma. Continuous background due to ionization appeared during the earliest stage of plasma development. The intensity of this background decreased after 100 ns and the atomic emission spectra of nitrogen (NI, 745 nm), oxygen (OI, 777 and 821 nm) and hydrogen (HI, 655.5 nm) appeared 200 ns after the laser pulse. The plasma temperature could be evaluated using the two-line ratio between the OI emission line intensities. We determined that simultaneous measurement using both the framing ICCD camera and an ICCD spectrometer with Cassegrain optics could be very useful for investigating the breakdown of laser-induced air plasma.

Local equivalence ratio measurement of CH<inf>4</inf>/air and C <inf>3</inf>H<inf>8</inf>/air laminar flames by laser-induced breakdown spectroscopy

Yuji Ikeda, Atsushi Nishiyama, Nobuyuki Kawahara, Eiji Tomita, Takashi Nakayama

Collection of Technical Papers - 44th AIAA Aerospace Sciences Meeting 16 11586 - 11598 2006年12月

The local equivalence ratios of CH4/air and C3H 8/air mixtures were measured using a laser-induced breakdown spectroscopy technique with a fiber-coupled ICCD spectrometer with Cassegrain optics. Localized breakdown plasma was generated from the pulse of a Q-switched Nd:YAG laser with a wavelength of 532 nm. This system allowed us to measure laser-induced plasma spectra with high spatial and temporal resolution. The specified intensity ratio and set up equivalence ratios were well correlated and found to be a good indicator in practical measurement. The intensity ratio indicated a remarkable relationship regardless the presence of the flame. For the unburned and burned regions, there were some differences in the change in the intensity ratio, but the calibration slopes were almost similar. It was found that this technique can measure the local equivalence ratio of methane or propane premixed laminar flame regardless a flame. The intensity ratio was not a function of the incident beam intensity or flow rate, which is very acceptable for practical measurement. In this experiment, the relative error was around 5%.

E213 レーザ干渉法を利用した流体温度計測センサ : 水の温度計測(計測1)

冨田栄二, 河原伸幸, 戸田泰治

熱工学コンファレンス講演論文集 2006 349 - 350 2006年11月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

In this study, a new sensor is proposed to determine water temperature. This sensor utilizes the difference in measurement length between two laser beams. Both are the test beams, and there is no reference beam. The two beams pass mostly through equal or closely arranged paths ; therefore, the effect of mechanical vibration on the two test beams is expected to be very small. This sensor was installed on a side wall of a vessel. The temperature near the sensor was also measured with a thermocouple as a reference. The response of the thermocouple was enough to follow the change in water temperature because the speed of temperature is very slow. This paper focuses on the confirmation and evaluation of this system of temperature measurement. The temperature measured with this system agreed well with that measured with a thermocouple. It was confirmed that this sensor system is useful for detecting changes in water temperature.

バイオマスガスによるマイクロパイロット着火ガスエンジンの性能特性

深谷信彦, 冨田栄二, 河原伸幸, 丸山慶土, 薦田哲男

研究発表会講演論文集 / エネルギー・資源学会 [編] 25 281 - 282 2006年6月

512 2次元平面粒径計測法を用いた非定常噴霧における噴霧液滴粒径・流速計測(エンジンシステムI)

河原伸幸, 冨田栄二, 松本敬吾

講演論文集 2006 ( 44 ) 193 - 194 2006年2月

Combustion Characteristics and Performance of Supercharged Micro-pilot Natural Gas Engine

Fukatani, N, Tomita, E, Kawahara, N, Maruyama, K, Komoda, T

FISITA2006, 2006年

Local Equivalence Ratio Measurement of CH4/air and C3H8/air Laminar Flames with and without flame front by LIBS

Y. Ikeda, A. Nishiyama, N. Kawahara, T. Nakayama, E. Tomita

LIBS2006, Oral presentation 2006年

Highly Spatially Resolved Measurements of Laser-induced Plasma in Laminar Premixed Methane-Air Flow

T. Nakayama, N. Kawahara, E. Tomita, Y. Ikeda, J.L. Beduneau

LIBS2006，poster 2006年

Development of an aerosol nozzle to optimally deliver insecticides to the target and improve the agglomerative characteristics of the spray

Ikeda, Y, Kim, S.M, Horibe, Y, Takaki, S, Kawahara, N

ICLASS2006, 2006年

火花点火機関におけるノッキング時の自着火部の可視化

河原伸幸, 冨田栄二

自動車技術会ガソリン機関部門シンポジウム， No.17-06,pp.24-29. 2006年

LIBS法を用いた層流予混合火炎における当量比計測

池田裕二, 西山淳, 河原伸幸, 冨田栄二

日本分光学会レーザー誘起プラズマ分光部会・日本鉄鋼協会学会部門研究会”次世代鉄鋼迅速オンサイト分析の実用化”・合同講演会 2006年

層流予混合ガスにおけるレーザ誘起プラズマの高空間・高時間分解光学計測

河原伸幸, 池田裕二, 中山崇, 冨田栄二

日本分光学会レーザー誘起プラズマ分光部会・日本鉄鋼協会学会部門研究会”次世代鉄鋼迅速オンサイト分析の実用化”・合同講演会 2006年

Anchor Point Structure Measurements for Laminar Propane/Air and Methane/Air Premixed Flame using the Local Chemiluminescence Spectra

Y. Ikeda, A. Nishiyama, S.M. Kim, N. Kawahara, E. Tomita

31st International Symposium on Combustion, 2006 ( 44 ) 205 - 206 2006年

Spatially and Temporally Resolved Optical Measurement of Laser Ignition for Laminar CH4/Air Mixtures

Nakayama, T, Kawahara, N, Tomita, E, Ikeda, Y, Beduneau, J

31st International Symposium on Combustion, 2006年

A New Sensor for Temperature Measurement of Water by Laser Interferometry Technique

Tomita, E, Kawahara, N, Toda, Y

13th Int. Symp. on Application of Laser Techniques on Fluid Mechanics, 2006年

In-Situ Fuel Concentration Measurement Using an IR Spark Plug Sensor by Laser Infrared Absorption Method- Application to a Rotary Engine-

Kawahara,N, Tomita,E, Hayashi, K, Tabata, M, Iwai, K, Kagawa, R

13th Int. Symp. on Application of Laser Techniques on Fluid Mechanics, 2006年

In-Situ Fuel Concentration Measurement near Spark Plug by 3.392 m Infrared Absorption Method —Pressure and Temperature Dependence of the Gasoline Molar Absorption Coefficient

Kawahara, N, Tomita, E, Nishiyama, A, Hayashi, K

SAE 2006 World Congress, 2006年

記述言語：英語

This paper describes the development and application of a spark plug sensor using a 3.392 μm infrared absorption technique to quantify the instantaneous gasoline concentration near the spark plug. We developed an in situ laser infrared absorption method using a spark plug sensor and a 3.392 μm He-Ne laser as the light source; this wavelength coincides with the absorption line of hydrocarbons. First, we established a database of the molar absorption coefficients of premium gasoline at different pressures and temperatures, and determined that the coefficient decreased with increasing pressure above atmospheric pressure. We then demonstrated a procedure for measuring the gasoline concentration accurately using the infrared absorption technique. The history of the molar absorption coefficient of premium gasoline during the experiment was obtained from the established database using measured in-cylinder pressures and temperatures estimated by taking the residual gas into consideration. These values provided instantaneous fuel concentrations in the engine cylinder. We examined the mixture formation process near the spark plug in a port-injected spark-ignition (SI) engine for different fuel injection timings, and determined that when the injection timing was delayed, a rich mixture remained near the top of the combustion chamber. Copyright © 2006 SAE International.

DOI： 10.4271/2006-01-0182

Local equivalence ratio measurement of CH4/Air and C3H8/Air laminar flames by Laser-Induced Breakdown Spectroscopy

Ikeda, Y. Nishiyama, A., *Kawahara, N. Tomita, E. Nakayama, T

44th AIAA Aerospace Sciences Meeting and Exhibit 2006年

DISI用インジェクタにおける微粒化過程の可視化

河原伸幸, 冨田栄二, 中山智裕, 住田守

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 14 115 - 120 2005年11月

Measurement of flame propagation characteristics in an SI engine using micro-local chemiluminescence technique

Nobuyuki Kawahara, Eiji Tomita, Akira Takeuchi, Shigeyuki Arimoto, Yuji Ikeda, Atsushi Nishiyama

SAE Technical Papers 2005年

記述言語：英語

A small Cassegrain optics sensor was developed to measure local chemiluminescence spectra and the local chemiluminescence intensities of OH*, CH*, and C2* in a four-stroke spark-ignition (SI) engine in order to investigate the propagation characteristics of the turbulent premixed flame. The small Cassegrain optics sensor was an M5 type that could be installed in place of a pressure transducer. The measurements could be used to estimate the flame propagation speed, burning zone thickness, and local air/fuel (A/F) ratio for each cycle. The specifications of the small Cassegrain optics sensor were the same as those used for previous engine measurements. In this paper, measurements were made of several A/F ratios using gasoline to fuel the model engine. The performances of two Cassegrain optics sensors were compared to demonstrate the advantages of the new small sensor by measuring the local chemiluminescence intensities of a turbulent premixed flame in the model engine. The measurements suggested that the small Cassegrain optics sensor is superior to the conventional Cassegrain sensor and can provide stable data for measurements over several hours, which should be sufficient for practical combustion diagnostics. This sensor proved useful for estimating the flame propagation characteristics. In addition, the sensor should be useful for local A/F ratio measurements in an engine cylinder. Copyright © 2005 SAE International.

DOI： 10.4271/2005-01-0645

In-situ unburned gas temperature measurement in a spark ignition engine using laser interferometry

Nobuyuki Kawahara, Eiji Tomita, Kenji Ohnishi, Kazuhiro Goto

SAE Technical Papers 2005年

記述言語：英語

A heterodyne interferometry system with a fiber-optic sensor was developed to measure the temperature history of unburned gas in a spark-ignition engine. A polarization-preserving fiber and metal mirror were used as the fiber-optic sensor to deliver the test beam to and from the measurement region. This fiber-optic sensor can be assembled in an engine cylinder head without a lot of improvements of an actual engine. Adjustment system in the sensor was revised to face the distributed index lens with metal mirror. Before the flame arrived at the developed fiber-optic sensor, measured temperature was almost same with the temperature history after the spark, assuming that the process that changes the unburned gas is adiabatic. In situ unburned gas temperature measurements before knocking in a commercially produced SI engine can be carried out using developed fiber-optic heterodyne interferometry system. Although the heterodyne interferometry with the developed fiber-optic sensor provides the mean temperature along the line of sight, the feasibility of our system was sufficient to be applied to temperature history measurement of an unburned gas compressed by flame propagation in an engine cylinder. The developed heterodyne interferometry with fiber-optic sensor has a good feasibility to measure the unburned gas temperature history in the commercially produced spark-ignition engine. Copyright © 2005 SAE International.

DOI： 10.4271/2005-01-0646

Concentration Measurement of Unburned Hydrocarbons in Exhaust Gas from an SI Engine by Using 3.392 micrometer Absorption Method

Tomita, E, Kawahara, N

6th JSME-KSME Thermal Engineering Conference, 2005年

In-spark-plug sensor for analyzing the initial flame and its structure in an SI engine

Yuji Ikeda, Atsushi Nishiyama, Nobuyuki Kawahara, Eiji Tomita, Shigeyuki Arimoto, Akira Takeuchi

SAE Technical Papers 2005年

記述言語：英語

An in-spark-plug flame sensor was developed to measure local chemiluminescence near the spark gap in a practical spark-ignition (SI) engine in order to study the development of the initial flame kernel, flame front structure, transient phenomena, and the correlation between the initial flame kernel structure and cyclic variation in the flame front structure, which influences engine performance directly. The sensor consists of a commercial instrumented spark plug with small Cassegrain optics and an optical fiber. The small Cassegrain optics were developed to measure the local chemiluminescence intensity profile and temporal history of OH*, CH*, and C 2* at the flame front formed in a turbulent premixed flame in an SI engine. A highresolution monochromator with an intensified chargecoupled device (ICCD) and spectroscopy using optical filters and photomultiplier tubes (PMTs) were used to measure the time-series of the three radicals, as well as the in-cylinder pressure. Measurements were made at different engine speeds in an unmodified 223-cc practical SI engine fueled with gasoline. Stable data were obtained over several hours with little noise, and were of the same quality as data from a small M5-type sensor installed instead of a pressure transducer. The relationships between the radical intensities and indicated mean effective pressure (IMEP) were examined and typical cyclic variation was measured at speeds over 7,000 rpm. The behavior of the initial flame was followed from its arrival at the measurement point. The arrival time was faster and IMEP was larger at stoichiometry than under other air/fuel (A/F) conditions. Copyright © 2005 SAE International.

DOI： 10.4271/2005-01-0644

点火プラグ実装型燃料濃度計測センサ

河原伸幸, 冨田栄二

日本機械学会誌 Vol.108, No.1037, p311. ( 1037 ) 311 - 311 2005年

Fuel Breakup near Nozzle Exit of Multi-Hole Injector for DISI Engine

Kawahara, N. Tomita, E. Nakayama, T. Sumida, M

18th Internal Combustion Engine Symposium (International) 2005年

Local stoichiometry measurement of CH4/Air and C3H8/Air laminar flames by LIBS

Ikeda, Y. Nishiyama, A., *Kawahara, N. Tomita, E. Kurahashi, T

Pacifichem 2005 2005年

Highly spatially resolved time evolution of laser-induced air plasma spectrum

Kawahara, N. Tomita, E. Nakayama, T. Kurahashi, T. Ikeda, Y. Nishiyama, A

Pacifichem 2005 2005年

LDV/PDAの基礎と応用

河原伸幸

機械の研究 Vol.57, No.9, pp.937-944. ( 9 ) 937 - 944 2005年

超音波浮揚における液滴近傍音響流のPIV計測

河原伸幸, 冨田栄二

微粒化 2005年

In-spark-plug sensor for analyzing the initial flame and its structure in an SI engine

Yuji Ikeda, Atsushi Nishiyama, Nobuyuki Kawahara, Eiji Tomita, Shigeyuki Arimoto, Akira Takeuchi

SAE Technical Papers 2005年

記述言語：英語

An in-spark-plug flame sensor was developed to measure local chemiluminescence near the spark gap in a practical spark-ignition (SI) engine in order to study the development of the initial flame kernel, flame front structure, transient phenomena, and the correlation between the initial flame kernel structure and cyclic variation in the flame front structure, which influences engine performance directly. The sensor consists of a commercial instrumented spark plug with small Cassegrain optics and an optical fiber. The small Cassegrain optics were developed to measure the local chemiluminescence intensity profile and temporal history of OH*, CH*, and C 2* at the flame front formed in a turbulent premixed flame in an SI engine. A highresolution monochromator with an intensified chargecoupled device (ICCD) and spectroscopy using optical filters and photomultiplier tubes (PMTs) were used to measure the time-series of the three radicals, as well as the in-cylinder pressure. Measurements were made at different engine speeds in an unmodified 223-cc practical SI engine fueled with gasoline. Stable data were obtained over several hours with little noise, and were of the same quality as data from a small M5-type sensor installed instead of a pressure transducer. The relationships between the radical intensities and indicated mean effective pressure (IMEP) were examined and typical cyclic variation was measured at speeds over 7,000 rpm. The behavior of the initial flame was followed from its arrival at the measurement point. The arrival time was faster and IMEP was larger at stoichiometry than under other air/fuel (A/F) conditions. Copyright © 2005 SAE International.

DOI： 10.4271/2005-01-0644

Liquid Sheet Break-up of High-Pressure Swirl Injector for DISI Engine(Spray Technologies, Atomization)

Kawahara Nobuyuki, Tomita Eiji, Kasahara Daisuke, Sumida Mamoru

The ... international symposium on diagnostics and modeling of combustion in internal combustion engines 2004 ( 6 ) 279 - 285 2004年8月

記述言語：英語出版者・発行元：一般社団法人日本機械学会

Experimental investigations of fuel breakup very close to nozzle of practical high-pressure swirl injector, which is used in direct injection spark ignition (DISI) engine, were carried out. In DISI engines, fuel is directly injected into cylinder therefore the spray characteristics and mixture formation are of primary importance. Many experimental investigations using several measurement techniques like laser sheet method with high-speed camera, LIF or PDA have been carried out for better understandings of spray and combustion characteristics. However, experimental investigations of atomization process were restricted due to very high-speed and very small region phenomena. Although scale-up models have been used to study the primary spray structure, it is impossible to match Reynolds, Weber, and cavitation numbers and time scales in practical high-pressure swirl injector. Microscopic investigation of primary spray structure of practical swirl injector is needed. On the other hand, numerical simulations have been conducted for better understanding of spray formation process. These researches indicated qualitatively good agreement, but the initial conditions, such as liquid sheet thickness and break-up length, were not accurately since break-up process of the liquid sheet from swirl injector has not been examined. In numerical simulation of spray behavior, a sub-model for atomization phenomena is very important. Therefore the primary atomization process and the break-up process of liquid sheet play an important role. In this research, visualizations of primary spray formation process were demonstrated using a high-speed video camera (maximum speed: Imfps) with a long-distance microscope. Initial state and development of the spray were discussed under the different ambient (back) pressure condition. During the injection period, the length and thickness of the liquid sheet, which is produced from the nozzle exit, were measured using Ar-ion laser sheet and high-speed camera. Moreover, fluctuations of the length and thickness of liquid sheet were discussed. Three main conclusions were drawn from this study. (1) It has been shown that the liquid fuel column without swirl motion was injected as a compact jet at the beginning of the injection. During the injection period, the spray indicates the quasi-steady state mode. (2) Liquid film sheet has a ligament structure. Using Ar-ion laser sheet and high-speed camera, length and thickness of the liquid sheet can be measured. (3) Surface waves of liquid sheet can be recognized. Higher ambient (back) pressure makes shorter wavelength of surface waves of liquid sheet of swirl injector.

密閉燃焼室内における噴霧火炎と周囲空気導入(エンジンシステムII)

冨田栄二, 今橋武, 河原伸幸, 木本泰造

講演論文集 2004 ( 42 ) 241 - 242 2004年3月

PIV Measurement of High-Pressure Swirl Injector Spray near Nozzle Exit for DISI Engine

Kawahara, N. Tomita, E. Fukuda, D. Sumida, M

7th International Congress on Optical Particle Characterization, 2004年

Fuel breakup near nozzle exit of high-pressure swirl injector for gasoline direct injection engine

Nobuyuki Kawahara, Eiji Tomita, Daisuke Kasahara, Takashi Nakayama, Mamoru Sumida

SAE Technical Papers 2004年

記述言語：英語

Experimental investigations of fuel breakup very close to nozzle of practical high-pressure swirl injector, which is used in gasoline direct injection (GDI) engine, were carried out. In GDI engines, fuel is directly injected into cylinder therefore the spray characteristics and mixture formation are of primary importance. In this research, visualizations of primary spray formation process were demonstrated using a high-speed video camera (maximum speed: 1Mfps) with a long-distance microscope. Initial state and development of the spray were discussed under the different injection pressure condition. During the injection period, the length and thickness of the liquid sheet, which is produced from the nozzle exit, were measured using Ar-ion laser sheet and high-speed camera. Primary spray structure and behavior of liquid sheet, especially surface wave of liquid sheet, at nozzle exit were discussed using obtained images. Three main conclusions were drawn from this study. (1) It has been shown that the liquid fuel column without swirl motion was injected as a compact jet at the beginning of the injection. During the injection period, the spray indicates the quasi-steady state mode. (2) Liquid film sheet has a ligament structure. Using Ar-ion laser sheet and high-speed camera, length and thickness of the liquid sheet can be measured. Higher injection pressure causes thinner thickness and shorter length of liquid sheet. (3) Surface waves of liquid sheet can be recognized. Higher injection pressure makes larger wavelength of surface waves of liquid sheet of swirl injector. Copyright © 2004 SAE International.

DOI： 10.4271/2004-01-0542

3.392μm赤外吸収法を用いたエンジンシリンダ内点火栓近傍炭化水素系燃料濃度計測－実用機関への適用－

冨田栄二, 河原伸幸, 西山淳, 重永真宏

日本機械学会論文集 (B編), 70 ( 690 ) 518 - 524 2004年

記述言語：日本語

An infrared absorption method was used to determine the fuel concentration with a 3.392 μm He-Ne laser. The effects of pressure and temperature on the molar absorption coefficients of hydrocarbon fuels were clarified, so that it increased with increasing temperature and decreased with increasing pressure. Molar absorption coefficient of multi-component fuel like gasoline can be estimated using molar absorption coefficient of each component and considering mass balance. By exchanging an ordinary spark-plug for & spark-plug with a developed sensor in which light can pass through mixture in the combustion chamber, successive measurement of fuel concentration was performed in a spark-ignition engine. The effects of liquid droplets, mechanical vibration, and other gas like H2O on measurement accuracy were discussed.

DOI： 10.1299/kikaib.70.518

3.392μm赤外吸収法を用いたエンジンシリンダ内点火栓近傍炭化水素系燃料濃度計測－メタン〜空気均一予混合気による検討－

冨田栄二, 河原伸幸, 重永真宏, 西山淳

日本機械学会論文集 (B編), 70 ( 690 ) 511 - 517 2004年

記述言語：日本語

A fiber optic system linked to the optical sensor installed in the spark plug, in which light can pass through the combustion chamber, was developed to determine the fuel concentration near the spark-plug successively using an infrared absorption method. A He-Ne laser with a wavelength of 3.392 μm that coincides with the absorption line of hydrocarbons was used as a light source. By exchanging an ordinary spark plug into this spark plug with the optical sensor, sucessive measurement of fuel concentration before the spark timing near the spark-plug was performed in a spark-ignition engine inducted with homogeneously mixed method methane-air. The fuel concentration was determined from law of Lambert-Beer in consideration for the effects of pressure and temperature on molar absorption coefficient of methane.

DOI： 10.1299/kikaib.70.511

Development of Combustion Facility of Constant-Volume Vessel for Investigating Combustion Characteristics of Banker Fuel Oil

Tomita, E., *Kawahara, N. Ohuchi, T. Imahashi, T. Takasu, I. Morinaka, H. Yokota, K

24th CIMAC World Congress 2004, 2004年

Combustion Characteristics and Performance of Supercharged Single Cylinder Natural Gas Engine Ignited with Pilot Injection of Diesel Fuel

Tomita, E., *Kawahara, N. Kinoshita, Y. Komoda, T. Sakane, A

FISITA 2004, 2004年

Homogeneous Charge Compression Ignition Combustion with Dimethyl Ether (Effect of Stratified Fuel Concentration)

Kawahara, N. Tomita, E. Arimoto, S

FISITA 2004, 2004年

Time-series A/F Analysis in a SI Engine by Micro-Local Chemiluminescence Technique

Ikeda, Y., *Kawahara, N. Tomita, E

Proc. of 6th COMODIA 2004, 2004 ( 6 ) 455 - 462 2004年

記述言語：英語出版者・発行元：一般社団法人日本機械学会

A small flame sensor was developed to measure the local chemiluminescence intensity of OH*, CH* and 2* in a four-stroke spark-ignition engine in order to understand flame front characteristics, flame propagation speed and local air/fuel (A/F) ratios. This sensor was installed where a pressure transducer was located. The dimensions of the sensor were those of the M5 type; the specifications of the developed small Cassegrain optics were the same as those used in previous engine measurements. The measurements were carried out at engine speeds of 600 and 1200 rpm using propane and gasoline fuels with no hardware modification in a 374.7 cc. model engine. Two types of Cassegrain optics were examined to measure local chemiluminescence of the flame in the engine. The small optics developed can provide very stable data for an experiment lasting several hours, which is sufficient to conduct practical combustion diagnostics. The measurements results with propane and gasoline demonstrated that this sensor is little influenced by fuel type, and the flame propagation speed was similar under both conditions. Although the sensor must be calibrated for a particular engine initially, it can measure local A/F and flame parameters in each cycle in practical engines. On-board diagnostics can be performed using this sensor and the flame speed and local equivalence ratio at the flame front can be calculated without modifying the engine hardware. This sensor should prove useful for measuring flame structure and stoichiometry in order to reduce cyclic variation and give the optimum control of each cylinder in practical engines.

Liquid Sheet Break-up of High-Pressure Swirl Injector for DISI Engines

Kawahara, N. Tomita, E. Kasahara, D. Sumida, M

Proc. of 6th COMODIA 2004, 2004年

Temperature Measurements of Laminar Propane/Air Premixed Flame using Detailed OH* Spectra Intensity Ratio

Y. Ikeda, T. Kurahashi, *N. Kawahara, E. Tomita

12th Int. Symp. on Application of Laser Techniques on Fluid Mechanics, 2004年

Measurement of Unburned Gas Temperature in an SI Engine Using Fiber-Optic Laser Interferometry

Kawahara, N. Tomita, E. Takasu, K. Goto, K

12th Int. Symp. on Application of Laser Techniques on Fluid Mechanics, 2004年

Spectrum Analysis of Chemiluminescence in HCCI Combustion with Dimethyl Ether

Kawahara, N. Tomita, E

Lean Combustion Technology II, Engineering Foundation 2004年

Diluted and Stoichiometric Combustion of Dual Fuel (Methane and Gas Oil) Engine with HCCI Concept

Tomita, E, Kawahara, N

Lean Combustion Technology II, Engineering Foundation 2004年

定容容器内燃料－空気混合気の燃焼に及ぼす旋回乱流場および層状燃料濃度場の影響（第2報，燃料濃度場および乱流場が燃焼特性に及ぼす影響

西山淳, 冨田栄二, 河原伸幸, 吉山定見, 浜本嘉輔

日本機械学会論文集 (B編), 70 ( 692 ) 1092 - 1099 2004年

記述言語：日本語

A swirling flow and rich fuel concentration near the center were produced in a vessel by tangentially charging air and fuel injection. Propane was used as fuel. Fuel concentration distribution was measured with laser induced fluorescence (LIF) method using acetone as a tracer. It was confirmed that the center-rich stratified fuel concentration was produced. In order to estimate the pattern of the fuel concentration field, the Gaussian fitting method was applied to the equivalence ratio profile. Fuel distribution history obtained from LIF measurement agreed with the calculation result using axisymmetric diffusion equation. The initial stage of combustion was greatly affected by the fuel concentration distribution in the vicinity of the spark location. The stronger turbulence intensity accelerated combustion and main combustion became shorter under the same fuel distribution conditions.

DOI： 10.1299/kikaib.70.1092

in Situ Fuel Concentration Measurement near Spark Plug by 3.39 m Infrared Absorption Method (Application to a Port Injected Lean-Burn Engine)

Nishiyama, A., *Kawahara, N. Tomita, E. Fujiwara, M. Ishikawa, N. Kamei, K. Nagashima, K

SAE 2004 World Congress, 2004年

記述言語：英語

In this study, a spark plug sensor for in-situ fuel concentration measurement was applied to a port injected lean-burn engine. Laser infrared absorption method was employed and a 3.392 μm He-Ne laser that coincides with the absorption line of hydrocarbons was used as a light source. In this engine, the secondary valve lift height of intake system was controlled to obtain appropriate swirl and tumble flow in order to achieve lean-burn with the characteristics of intake flow. For such in-cylinder stratified mixture distribution, the fuel concentration near the spark plug is very important factor that affects the combustion characteristics. Therefore, the mixture formation process near the spark plug was investigated with changing fuel injection timing. Under the intake stroke, the timing that fuel passed through near the spark plug depended largely on the fuel injection timing. Under the compression stroke, mixture formation process near the spark plug indicated different characteristics with injection timings. As the injection timing was retarded, rich mixture remained near the top of the combustion chamber. Furthermore, the relation between the fuel concentration near the spark plug and the combustion characteristics was discussed. The initial combustion became faster and the coefficient of variation in IMEP became lower as the rich mixture existed near the spark plug. Copyright © 2004 SAE International.

DOI： 10.4271/2004-01-1353

LDV，PDAの基礎と応用

河原伸幸

No.04-45講習会基礎教育講習会‐エンジンにおける実験・計測の基礎と応用（その 9），日本機械学会エンジンシステム部門， pp.11-18 2004年

赤外線吸収法を利用した点火栓近傍燃料濃度センサの開発

冨田栄二, 河原伸幸

工業加熱， Vol.41, No.3, pp.10-16 ( 3 ) 10 - 16 2004年

レーザ計測によるエンジン内諸現象の観察

河原伸幸

若手研究最前線，エンジンテクノロジー， No.30,pp.52-59 ( 1 ) 52 - 59 2004年

LDV，PDAの基礎と応用

河原伸幸

No.03-101講習会基礎教育講習会‐エンジンにおける実験・計測の基礎と応用（その 8），日本機械学会エンジンシステム部門， pp.11-18 2004年

インジェクタのノズル近傍における噴霧形成過程の可視化

河原伸幸

第12回微粒化フォーラム「噴霧特性の測定原理と実習」テキスト， pp.37-43 2004年

Real Time HC Concentration Measurement in Exhaust Gas from A Spark-Ignition Engine by Using 3.392 m Absorption Method

Tomita, E, Kawahara, N

Journal of KONES International Combustion Engines, 2004年

Characteristics of Combustion and Exhaust Emissions in a Dual Fuel Engine with HCCI Concept -Diluted and Stoichiometric Combustion-

Tomita, E, Kawahara, N

Homogeneous Charge Compression Ignition Symposium 2004年

超音波浮揚場における液滴近傍の音響流解析

河原伸幸, 冨田栄二, 江種元

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 12 335 - 339 2003年12月

スワールインジェクタのノズル出口における液膜分裂状態の可視化

河原伸幸, 冨田栄二, 笠原大輔

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 12 249 - 253 2003年12月

In situ Measurement of Hydrocarbon Fuel Concentration near a Spark Plug in an Engine Cylinder by 3.392 m Infrared Laser Absorption Method - Application to Actual Engine -

Tomita, E, Kawahara, N, Nishiyama, A, Shigenaga, M

Measurement Science and Technology 14 ( 8 ) 1357 - 1363 2003年8月

ガソリンインジェクタのノズル近傍における噴霧形成過程の可視化

河原伸幸, 冨田栄二, 中山崇

可視化情報学会誌. Suppl. 23 ( 1 ) 49 - 52 2003年7月

709 小型 2 ストロークエンジンの不整燃焼改善に関する研究

冨田栄二, 中谷光伸, 河原伸幸, 稲毛克紀

講演論文集 2003 ( 41 ) 227 - 228 2003年2月

703 非定常ジメチルエーテル噴霧の挙動に関する研究

河原伸幸, 冨田栄二, 赤澤定樹

講演論文集 2003 ( 41 ) 215 - 216 2003年2月

Homogeneous charge compression ignition combustion with dimethyl ether - Spectrum analysis of chemiluminescence

Nobuyuki Kawahara, Eiji Tomita, Hisashi Kagajyo

SAE Technical Papers 2003年

記述言語：英語

Homogeneous Charge Compression Ignition (HCCI) combustion with dimethyl ether has been carried out in a single cylinder engine with a transparent piston. The engine was operated at 800 rpm with a wide-open throttle. The intake-premixed mixture was preheated with an electric heater to promote auto-ignition. HCCI combustion with dimethyl ether indicates multi-stage heat releases. Investigations were conducted with visualization of combustion in the cylinder and detailed and temporal spectroscopic measurements using spectrometer. In order to understand reaction mechanism of auto-ignition and combustion mechanism in HCCI engine, spectrum analysis of chemiluminescence was carried out. Three main conclusions were drawn from this study. (1) Spectrum from chemiluminescence at low temperature oxidation was obtained successfully using developed optical fiber probe. (2) Emitting lights from HCHO according to Emeléous's cool flame bands appear at low temperature reaction. (3) During the main heat release, the CO-O recombination spectrum was strong. There was a strong correlation between rate of heat release and the CO-O recombination spectrum. Copyright © 2003 Society of Automotive Engineers of Japan, Inc.

DOI： 10.4271/2003-01-1828

水素を用いた内燃機関の新燃焼法に関する研究

河原伸幸

（財）実吉奨学会，平成13年度研究報告集 Vol.20, pp.35-38 2003年

LDA，PDAの基礎と応用（応用例：噴霧粒子径および速度の同時計測など），

河原伸幸

第89回講習会エンジニアのための基礎からのレーザ応用最新技術，日本機械学会中国四国支部 pp.23-30 2003年

多種噴霧／工業分野

河原伸幸

微粒化 Vol.12, No.39, pp.105-107 2003年

In-Situ Fuel Concentration Measurement with Optical Spark Plug Sensor by 3.39 m Infrared Laser Absorption Method

Nishiyama, A, Kawahara, N, Tomita, E, Shigenaga, M

19th International Colloquium on the Dynamics of Explosions and Reactive Systems (ICDERS) 2003年

Effects of Swirl Flow and Inhomogeneous Concentration Fields on Combustion of Propane-Air Mixture in a Constant-Volume Vessel

Tomita, E, Nishiyama, A, Kawahara, N

19th International Colloquium on the Dynamics of Explosions and Reactive Systems (ICDERS) 2003年

Analysis of Two-Stage Heat Release in HCCI Combustion with Dimethyl Ether

Kawahara, N, Tomita, E, Kagajyo, H

19th International Colloquium on the Dynamics of Explosions and Reactive Systems (ICDERS) 2003年

Microscopic Observation of Primary Spray Structure of High-Pressure Swirl Injector for Gasoline Direct Injection Engine

Kawahara, N, Tomita, E, Nakayama, T, Sumida, M

The 9th Int. Conf. on Liquid Atomization and Spray Systems (ICLASS 2003), 2003年

In-Situ Fuel Concentration Measurement near Spark Plug by 3.392 μm Infrared Absorption Method (Application to Spark Ignition Engine)

Nishiyama, A., *Kawahara, N. Tomita, E

SAE Transactions - Journal of Engines, 2003年

記述言語：英語

This study measured the fuel concentration near a spark plug using a laser infrared absorption method. An IR spark plug sensor with a double-pass measurement length was developed. A He-Ne laser with a wavelength of 3.392 μm, which coincides with the absorption line of hydrocarbons, was used as the light source. In order to confirm the measurement accuracy, the concentrations of a methane-air mixture were measured in a compression-expansion engine. Then, the IR spark plug sensor was used for measurements in a 4-stroke spark-ignition engine fuelled with isooctane. The air/fuel ratio measured using this system clearly agreed with the mean air/fuel ratio. Copyright © 2003 SAE International.

DOI： 10.4271/2003-01-1109

メタン/ 軽油ディーゼル機関の燃焼・排気特性に及ぼす早期噴射およびEGRの影響

冨田栄二, 河原伸幸, 朴振宇, 山口良一

日本機械学会論文集Ｂ編 69 ( 680 ) 988 - 994 2003年

記述言語：日本語

Dual fuel natural gas engines have been studied for the purpose of near future engine. This study focuses on the effect of early injection of light oil and exhaust gas recirculation (EGR) fueled with methane from an inlet pipe on characteristics of combustion and exhaust emissions. The injection timing was changed from TDC to 50 degrees before the TDC. In the early injection timing, smoke was never seen and hydrocarbons were smaller compared with those at the normal injection timing. However, the combustion becomes too early to obtain an appropriate torque when the equivalence ratio increases. Then, moderate nitrogen dilution was very effective to retard the combustion with lower NOx, higher thermal efficiency and almost the same hydrocarbons and carbon monoxide. And it was found that the engine operates even under the condition of stoichiometric mixture.

DOI： 10.1299/kikaib.69.988

Transient temperature measurement of unburned gas in an engine cylinder using laser interferometry with a fiber-optic sensor

Nobuyuki Kawahara, Eiji Tomita, Mitsuru Ichimiya, Kouji Takasu, Naoki Tsuchida, Kazuhiro Goto

SAE Technical Papers 2003年

記述言語：英語

A heterodyne interferometry system with a fiber-optic sensor was developed to measure the temperature history of unburned gas in an engine cylinder. A polarization-preserving fiber and metal mirror were used as the fiber-optic sensor to deliver the test beam to and from the measurement region. This fiber-optic sensor can be assembled in the engine cylinder or the cylinder head without a lot of improvements of an actual engine. The feasibility of our system was sufficient to be applied to temperature history measurement of an unburned gas compressed by flame propagation in an engine cylinder. The resolution of the temperature measurement is approximately 0.7 K, and is dependent on both the sampling clock speed of the A/D converter and the length of the measurement region. Copyright © 2003 Society of Automotive Engineers of Japan, Inc.

DOI： 10.4271/2003-01-1799

定容容器内燃料‐空気混合気の燃焼に及ぼす旋回乱流場および層状燃料濃度場の影響（第1報，層状混合気の燃焼特性）

西山淳, 冨田栄二, 河原伸幸, 吉山定見, 浜本嘉輔

日本機械学会論文集Ｂ編 69 ( 687 ) 2531 - 2538 2003年

記述言語：日本語

A swirling flow was produced in a vessel by tangentially charging fuel-air mixture or air. Rich fuel concentration was formed near the center of the vessel by fuel injection. Mixture was ignited at the center of the vessel. Various swirling flow field and fuel concentration field were made by changing the mean equivalence ratio in the vessel, the timing of charging mixture and fuel injection. The mean equivalence ratio in the vessel was changed from 0.20 to 0.84. Appropriate mixture stratification enabled initial combustion to be faster than that of homogeneous mixture. Under the lean condition, the combustion efficiency was lower and flame could not propagate in the lean mixture region near the wall as the homogeneity of the mixture became larger. In the case of the slowest swirling condition, initial combustion and initial flame propagation became slower due to rich mixture near the center of the chamber.

DOI： 10.1299/kikaib.69.2531

In situ Measurement of Hydrocarbon Fuel Concentration near a Spark Plug in an Engine Cylinder by 3.392 m Infrared Laser Absorption Method - Discussion of Applicability with Homogeneous Methane-Air Mixture -

Tomita, E, Kawahara, N, Shigenaga, M, Nishiyama, A, Dibble, R

Measurement Science and Technology 14 ( 8 ) 1350 - 1356 2003年

記述言語：英語

A fibre optic system was developed to determine the fuel concentration near a spark plug using an infrared absorption method. The system was linked to an optical sensor installed in the spark plug, from which light could pass through the combustion chamber. By using this modified spark plug, successive measurements of the fuel concentration near the spark plug before ignition were performed in a spark-ignition engine burning homogeneously mixed methane-air. The fuel concentration was determined from the Lambert-Beer law by considering the dependence of the methane molar absorption coefficient on pressure and temperature. Three main conclusions were drawn from this study. First, the methane molar absorption coefficient was greater for lower pressures and decreased with increasing temperature and pressure above atmospheric pressure. The temperature and pressure effects were offset by each other, since the temperature effects were positive and the pressure effects were negative. Second, precise time-series data for the local fuel concentration were obtained by considering the in-cylinder pressure and temperature from an estimate of the methane molar absorption coefficient. And third, the measured air/fuel ratio near the spark plug before ignition agreed with the preset value when the developed optical sensor was used under motoring and firing conditions.

DOI： 10.1088/0957-0233/14/8/321

光ヘテロダイン干渉法による未燃焼ガス温度変化計測

河原伸幸, 冨田栄二, 鎌倉寛

日本機械学会論文集Ｂ編 69 ( 677 ) 229 - 235 2003年

記述言語：日本語

This paper demonstrates an application of the optical heterodyne interferometry, a laser-based technique for measuring the temperature history of gas in combustion devices, such as internal combustion engines. The technique is based on refractive index measurements using laser interferometry along a line of sight. The temperature history of gas can be determined from the pressure history in the combustion chamber, the gas composition, and the laser interference intensity. A polarization-preserving fiber was used to deliver the test beam to and from the test section to improve the feasibility of the system as a sensor probe. The temperature of the unburned mixture in the end-gas region of a constant volume combustion chamber and in an engine cylinder were measured during flame propagation. The accuracy of the measurement and the feasibility of this system are discussed. The measurement accuracy of our system was sufficient to be applied to temperature history measurement of an unburned gas compressed by flame propagation in an engine cylinder. The uncertainty of this method is within ± 10 K. The resolution of the temperature measurement was approximately 0.5 K, and was dependent upon both the sampling clock speed of the A/D converter and the length of the test section. This optical heterodyne interferometry system may also be used for other applications that require a fast response time to measure the density and pressure of a gas, and thereby obtain a transient temperature record.

DOI： 10.1299/kikaib.69.229

In situ measurement of hydrocarbon fuel concentration near a spark plug in an engine cylinder using the 3.392 μm infrared laser absorption method: Application to an actual engine

Eiji Tomita, Nobuyuki Kawahara, Atsushi Nishiyama, Masahiro Shigenaga

Measurement Science and Technology 14 ( 8 ) 1357 - 1363 2003年

記述言語：英語

An infrared absorption method with a 3.392 umm He-Ne laser was used to determine the hydrocarbon fuel concentration near the spark plug in a spark-ignition engine. Iso-octane was used for the fuel. The pressure and temperature dependence of the molar absorption coefficient was clarified. The molar absorption coefficients of a multi-component fuel such as gasoline were estimated by using the coefficient of each component and considering the mass balance. A sensor was developed and installed in a spark plug, which was substituted in place of an ordinary spark plug in a spark-ignition engine. Light can pass from the sensor through the engine cylinder to measure the fuel concentration. The effects of liquid droplets inside the engine cylinder, mechanical vibrations and other gases such as H2O and CO2 on the measurement accuracy were considered. Four main conclusions were drawn from this study. First, the pressure and temperature effects on the molar absorption coefficient of liquid fuel vapour were determined independently in advance using a constant-volume vessel. The pressure and temperature dependence of the molar absorption coefficient was determined under engine firing conditions. Second, the molar absorption coefficients of a multi-component hydrocarbon fuel such as gasoline were estimated by considering the molar fraction of each component. Third, in situ measurements of the hydrocarbon fuel concentration in an actual engine were obtained using the spark plug sensor and the molar absorption coefficient of iso-octane. The concentration near the spark plug just before ignition was almost in agreement with the mean value that was obtained from the measurement of the flow rate made with a burette, which represented the mean value averaged over many cycles. And fourth, no liquid droplets were observed at near-idling conditions. The effects of other gases, such as CO, CO2 and H2O, can be neglected.

DOI： 10.1088/0957-0233/14/8/322

Combustion and Exhaust Emissions in a Hydrogen Fueled Engine Ignited with Light Oil

Tomita, E, Kawahara, N, Piao, Z, Yamaguchi, R

Proc. of The 6th ASME-JSME Thermal Engineering Joint Conference 2003 ( 6 ) 138 - 138 2003年

記述言語：英語出版者・発行元：日本機械学会

It is necessary to increase thermal efficiency and reduce exhaust emission for internal combustion engines. Alternative fuels that are not made of petroleum are also one of the important factors. Hydrogen is expected to be one of the most prominent fuels in the near future for solving greenhouse problem, protecting environment and saving petroleum. In this study, a dual fuel engine operated with hydrogen and light oil was investigated. The configuration of the diesel engine was not changed except changing the injection timing over very wide range by setting an injection pump synchronized with the engine revolution. Hydrogen was supplied in an intake port with air and light oil was injected into the cylinder. The rate of heat release was determined from the pressure in the cylinder. Here, the concept of HCCI combustion was applied to this engine. When the injection timing of the light oil into the cylinder was advanced to 40 or 50 degrees before the compression top dead center, the light oil was well mixed with hydrogen-air mixture and the combustion became mild. As shown in Fig. A, NOx emissions decreased because of lean premixed combustion without the region of high temperature of burned gas. When hydrogen was mixed with inlet air, emissions of HC, CO and CO_2 decreased Without exhausting smoke while indicated thermal efficiency was slightly smaller than that in ordinary diesel combustion. In particular, both smoke and NOx were almost zero and HC was low when the injection timing is significantly advanced. Moreover, the effects of hydrogen ratio and spray angle on exhaust emissions and engine performance were investigated. If the operating conditions in early injection are chosen appropriately, it is considered that low NOx, HC, CO and CO_2,and zero smoke, can be achieved.[figure]

TED-AJ03-397 HOMOGENEOUS CHARGE COMPRESSION IGNITION COMBUSTION WITH DIMETHYL ETHER : ANALYSIS OF TWO-STAGE HEAT RELEASE :

Kawahara Nobuyuki, Tomita Eiji, Kagajyo Hisashi

Proceedings of the ... ASME/JSME Thermal Engineering Joint Conference 2003 ( 6 ) 143 - 143 2003年

記述言語：英語出版者・発行元：日本機械学会

Although homogeneous charge compression ignition (HCCI) engines are expected to have both higher thermal efficiency and lower nitrogen oxide (NOx) emissions, they still have problems with high hydrocarbon (HC) and carbon monoxide (CO) production, high rates of heat release, and difficulty in controlling auto-ignition. In order to control auto-ignition in HCCI engines, the reaction mechanism of auto-ignition must be understood. Dimethyl ether (DME), a promising alternative fuel that is suitable for compression ignition engines, shows very strong low-temperature kinetic reactions in HCCI. HCCI combustion shows a peculiar two-stage heat release. The first stage of the heat release curve is associated with low-temperature kinetic reactions, and the time delay between the first and main heat release is attributed to the negative temperature coefficient regime. A study of HCCI fueled with DME may provide useful information on the low-temperature kinetic reactions in HCCI operation. This study investigated the auto-ignition characteristics of an HCCI engine fueled with DME using a single[figure] cylinder engine with a transparent piston. The engine was operated at 800 rpm with a wide-open throttle. The intake-premixed mixture was preheated with an electric heater to promote auto-ignition. HCCI combustion was examined using instantaneous flame images obtained from a high-speed video. The influences of equivalence ratio and intake temperature on the characteristics of auto-ignition in the HCCI engine were investigated. Spectrum analyses of chemiluminescence using spectroscopy were carried out to investigate the two-stage heat release. Three main conclusions were drawn from this study. (1) The hot-flame reaction progresses homogeneously. DME combustion was found to be non-luminous. (2) With increasing intake temperature and equivalence ratio, varying heat release was observed. Three-stage heat release was also observed. (3) During the main heat release, the CO-O recombination spectrum was strong. There was a strong correlation between rate of heat release and the CO-O recombination spectrum.[figure]

In-situ fuel concentration measurement near spark plug by 3.39 MM infrared absorption method (development of a double-pass optical sensor)

A. Nishiyama, N. Kawahara, E. Tomita

International Symposium on Combustion Abstracts of Works-in-Progress Posters 169 2002年12月

It is very important to know the hydrocarbon fuel concentration near the spark plug. The possibility of the concentration measurement near the spark plug using in-situ IR absorption method was presented. The fuel concentration near the spark plug was measured using an optical sensor with sapphire rods. A new optical sensor with double-pass measurement length was developed to increase the measurement accuracy. The light source with wavelength of 3.392 μm was introduced into an optical fiber and guided to a spark plug. This optical sensor was constructed by modifying a commercially available instrumented spark plug. Original is an abstract.

Flame propagation and combustion characteristics of stratified charge propane-air mixture with swirling flow in a constant-volume vessel

A. Nishiyama, E. Tomita, N. Kawahara, S. Yoshiyama, Y. Hamamoto

International Symposium on Combustion Abstracts of Works-in-Progress Posters 207 2002年12月

The flame propagation and the combustion characteristics of stratified fuel concentration field were studied using a cylindrical constant volume vessel. A swirling fuel-air mixture was produced in the vessel. A rich fuel concentration was formed near the center of the vessel by the injection of propane and lean mixture near the wall. The gas flow field was obtained with a laser Doppler velocimeter in advance. The pressure history in the combustion chamber was analyzed to determine the combustion characteristics. The flame could propagate and the combustion occurred even in an ultra lean mixture of equivalence ratio of 0.3:1 in total. As the fuel concentration near the spark location approximates stoichiometric mixture ratio, flame propagation of the initial stage of the combustion became faster. When stratified mixtures with the same pattern of fuel concentration but different turbulence intensities were considered, the main combustion period decreased with turbulence intensity, since the burning velocity also increased. Original is an abstract.

Fiber-optic heterodyne interferometry temperature measurement of unburned gas in a HCCI engine fueled with DME

Nobuyuki Kawahara, Eiji Tomita, Mitsuru Ichimiya

International Symposium on Combustion Abstracts of Works-in-Progress Posters 170 2002年12月

Various global environmental issues are related to the use of internal combustion engines, including air pollution and energy concerns. With homogeneous charge compression ignition (HCCI) engine, it is possible to operate with ultra lean premixed mixtures and to lead low NOx and soot-particle emissions. The temperature of the unburned mixture in a HCCI engine, fueled with dimethyl ether, was measured using fiber-optic heterodyne interferometry along a line of sight. The measurement accuracy of the developed system was sufficient to determine the temperature history of unburned mixture in HCCI operation. The uncertainty of this method was within ± 15K. The resolution of temperature measurements was ∼ 0.5 K, and depended on the sampling clock speed of the A/D converter and the length of the test section. Original is an abstract.

504 二元燃料ディーゼル機関における早期噴射の燃焼および排気特性

冨田栄二, 河原伸幸, 山口良一, 朴振宇

講演論文集 2002 ( 40 ) 153 - 154 2002年2月

503 赤外吸収法による火花点火機関排気管内炭化水素濃度の測定

冨田栄二, 河原伸幸, 中溝大和

講演論文集 2002 ( 40 ) 151 - 152 2002年2月

Unburned gas temperature measurement in a spark-ignition engine using fibre-optic heterodyne interferometry

N Kawahara, E Tomita, H Kamakura

MEASUREMENT SCIENCE AND TECHNOLOGY 13 ( 1 ) 125 - 131 2002年1月

記述言語：英語出版者・発行元：IOP PUBLISHING LTD

A fibre-optic heterodyne interferometry system was developed to obtain the temperature histories of an unburned mixture with high temporal resolution non-intrusively. In laser interferometry, the effective optical path length of the test beam changes with the gas density and corresponding changes of the refractive index. Therefore, the temperature history of an unburned gas can be determined from the pressure and phase shift of the heterodyne signal. A polarization-preserving fibre is used to deliver the test beam to and from the test section, to improve the feasibility of the system as a sensor probe. The temperature of the unburned mixture in the end-gas region of a constant-volume combustion chamber and in an engine cylinder was measured during flame propagation. The accuracy of the measurements and the feasibility of this system are discussed. The measurement accuracy of our system was sufficient to be applied to temperature history measurement of an unburned gas compressed by flame propagation in a constant-volume combustion chamber. The uncertainty of this method is within +/-10 K. The resolution of the temperature measurement is approximately 0.5 K, and is dependent on both the sampling clock speed of the A/D converter and the length of the test section, This fibre-optic heterodyne interferometry system can also be used for other applications that require a transient temperature with a fast response time.

DOI： 10.1088/0957-0233/13/1/316

レーザ干渉法を利用した高応答・高精度温度センサの開発

河原伸幸

新エネルギー・産業技術総合開発機構，平成１２年度即効産業技術研究助成事業，研究成果報告書 2002年

Effects of EGR and early injection of diesel fuel on combustion characteristics and exhaust emissions in a methane dual fuel engine

Eiji Tomita, Nobuyuki Kawahara, Zhenyu Piao, Ryoichi Yamaguchi

SAE Technical Papers 2002年

記述言語：英語

A dual fuel engine fueled with methane from an inlet port and ignited with diesel fuel was prepared. This study focuses on the effects of early injection and exhaust gas recirculation (EGR) on the characteristics of combustion and exhaust emissions. The injection timing was changed between TDC and 50 degrees before the TDC. In the early injection timing, smoke was never seen and hydrocarbons were smaller compared with those at the normal injection timing. However, the combustion becomes too early to obtain an appropriate torque when the equivalence ratio increases. Then, moderate EGR was very effective to force the combustion to retard with lower NOx, higher thermal efficiency and almost the same hydrocarbons and carbon monoxide. The engine operated even under the condition of stoichiometric mixture. Copyright © 2002 SAE International.

DOI： 10.4271/2002-01-2723

Effects of EGR and early injection of diesel fuel on combustion characteristics and exhaust emissions in a methane dual fuel engine

Eiji Tomita, Nobuyuki Kawahara, Zhenyu Piao, Ryoichi Yamaguchi

SAE Technical Papers 2002年

記述言語：英語

A dual fuel engine fueled with methane from an inlet port and ignited with diesel fuel was prepared. This study focuses on the effects of early injection and exhaust gas recirculation (EGR) on the characteristics of combustion and exhaust emissions. The injection timing was changed between TDC and 50 degrees before the TDC. In the early injection timing, smoke was never seen and hydrocarbons were smaller compared with those at the normal injection timing. However, the combustion becomes too early to obtain an appropriate torque when the equivalence ratio increases. Then, moderate EGR was very effective to force the combustion to retard with lower NOx, higher thermal efficiency and almost the same hydrocarbons and carbon monoxide. The engine operated even under the condition of stoichiometric mixture. Copyright © 2002 SAE International.

DOI： 10.4271/2002-01-2723

In situ fuel concentration measurement near spark plug in spark-ignition engines by 3.39 μm infrared laser absorption method

Eiji Tomita, Nobuyuki Kawahara, Sadami Yoshiyama, Akihiko Kakuho, Teruyuki Itoh, Yoshisuke Hamamoto

Proceedings of the Combustion Institute 29 ( 1 ) 735 - 741 2002年

記述言語：英語

Recently, improving the thermal efficiency and reducing the exhaust emissions of internal combustion engines have become crucial. To this end, it is important to determine the fuel concentration in the vicinity of the spark plug near the spark timing, because initial combustion affects the subsequent main combustion in spark-ignition engines. In this study, a fiber optic system linked to an optical sensor installed in the spark plug, by means of which light can pass through the combustion chamber, was developed to determine the fuel concentration near the spark plug using an IR absorption method. A He-Ne laser with a wavelength of 3.39 μm that coincides with the absorption line of hydrocarbons was used as a light source. By exchanging an ordinary spark plug for this spark plug with the optical sensor, successive measurement of fuel concentration before the spark timing near the spark plug was performed in a port-injection spark-ignition engine fueled with iso-octane under the firing condition. The effects of pressure and temperature on the molar absorption coefficient of fuel were clarified in advance. The air/fuel ratio averaged for many cycles near the spark plug with this optical system agreed with that measured with a buret, which represented the mean value averaged over a protracted period. Next, this sensor was applied to determine the air/fuel ratio quantitatively in a direct-injection gasoline engine. As a result, it was clarified that the air/fuel ratio and its standard deviation near the spark plug have a strong relationship to stable engine operation.

DOI： 10.1016/S1540-7489(02)80094-3

Transient temperature measurement of unburned gas using optic heterodyne interferometry

N Kawahara, E Tomita, H Kamakura

LASER TECHNIQUES FOR FLUID MECHANICS 157 - 172 2002年

記述言語：英語出版者・発行元：SPRINGER-VERLAG BERLIN

Optical heterodyne interferometry was validated to measure the transient temperature of a gas by comparing the temperature history of unburned gas in a combustion chamber, caused by compression due to flame propagation, obtained by the heterodyne interferometry with temperature obtained by assuming adiabatic change. When the density of gas changes, the effective optical path length of the test beam changes with corresponding changes of the refractive index. Therefore, the temperature history of the gas can be determined by measuring the pressure and the phase shift of the interference signal. As a result, it is clearly recognized that a non-intrusive measurement in the transient gas temperature was made successfully by the optical heterodyne interferometry. The resolution of the temperature measurement is approximately 0.5 K, and is dependent upon both the sampling clock speed of the A/D converter and the length of the test section. Moreover, a polarization-preserving fiber was used to deliver the test beam to and from the test section to improve the feasibility of the system as a sensor probe. It may also be applied to other system requiring fast response density and temperature measurement of a gas, the latter necessitating a simultaneous record of transient pressure.

In-situ fuel concentration measurement near spark plug in spark-ignition engines by 3.39 μM infrared laser absorption method

Eiji Tomita, Nobuyuki Kawahara, Sasdami Yoshiyama, Akihiko Kakuho, Teruyki Itoh, Yoshisuke Hamamoto

International Symposium on Combustion Abstracts of Accepted Papers 29 ( 1 ) 735 - 741 2002年

記述言語：英語

Improving thermal efficiency and reducing the exhaust emissions of internal combustion engines have become crucial. Thus, it is important to determine the fuel concentration in the vicinity of the spark plug near the spark timing because initial combustion affects the following main combustion in spark-ignition engines. A fiber optic system linked to the optical sensor installed in the spark plug, by means of which light could pass through the combustion chamber, was developed to determine the fuel concentration near the spark plug using an IR absorption method. A He-Ne laser with a wavelength of 3.39 μm coinciding with the absorption line of hydrocarbons was utilized as a light source. By exchanging an ordinary spark plug for this spark plug with the optical sensor, successive measurement of fuel concentration before the spark timing near the spark plug was carried out in a port injection spark-ignition engine fueled with isooctane under the firing condition. The air/fuel ratio averaged for many cycles near the spark plug with this optical system agreed with that measured with a buret, which represented the mean value averaged over a protracted period. This sensor was also applied to determine air /fuel ratio quantitatively in a direct injection gasoline engine. As a result, it was clarified that the air/fuel ratio and its standard deviation near the spark plug had a strong relationship to the stable engine operation. Original is an abstract.

DOI： 10.1016/S1540-7489(02)80094-3

An Optical Sensor Instrumented in Spark Plug for In-situ Fuel Concentration Measurement in an Engine Cylinder by 3.39 mm Infrared Absorption Method,

Tomita, E, Kawahara, N, Shigenaga, M, Yoshiyama, S, Hamamoto, Y, Kakuho, A, Itoh, T, Dibble, R.W

11th Int. Symp. on Application of Laser Techniques on Fluid Mechanics 2002年

Transient Temperature Measurement of Unburned Gas in an Engine Cylinder Using Fiber-Optic Heterodyne Interferometry,

Kawahara, N, Tomita, E, Kamakura, H, Ichimiya, M

11th Int. Symp. on Application of Laser Techniques on Fluid Mechanics 2002年

In situ fuel concentration measurement near spark plug in spark-ignition engines by 3.39 μm infrared laser absorption method

Eiji Tomita, Nobuyuki Kawahara, Sadami Yoshiyama, Akihiko Kakuho, Teruyuki Itoh, Yoshisuke Hamamoto

Proceedings of the Combustion Institute 29 ( 1 ) 735 - 741 2002年

記述言語：英語出版者・発行元：Elsevier Ltd

Recently, improving the thermal efficiency and reducing the exhaust emissions of internal combustion engines have become crucial. To this end, it is important to determine the fuel concentration in the vicinity of the spark plug near the spark timing, because initial combustion affects the subsequent main combustion in spark-ignition engines. In this study, a fiber optic system linked to an optical sensor installed in the spark plug, by means of which light can pass through the combustion chamber, was developed to determine the fuel concentration near the spark plug using an IR absorption method. A He-Ne laser with a wavelength of 3.39 μm that coincides with the absorption line of hydrocarbons was used as a light source. By exchanging an ordinary spark plug for this spark plug with the optical sensor, successive measurement of fuel concentration before the spark timing near the spark plug was performed in a port-injection spark-ignition engine fueled with iso-octane under the firing condition. The effects of pressure and temperature on the molar absorption coefficient of fuel were clarified in advance. The air/fuel ratio averaged for many cycles near the spark plug with this optical system agreed with that measured with a buret, which represented the mean value averaged over a protracted period. Next, this sensor was applied to determine the air/fuel ratio quantitatively in a direct-injection gasoline engine. As a result, it was clarified that the air/fuel ratio and its standard deviation near the spark plug have a strong relationship to stable engine operation.

DOI： 10.1016/S1540-7489(02)80094-3

(2-08) Effects of Swirl Turbulent Flow Field and Inhomogeneous Concentration Field on Combustion of Fuel-Air Mixture in a Constant Volume Vessel((SI-3)S. I. Engine Combustion 3-Flow and Combustion)

KAWAHARA Nobuyuki, TOMITA Eiji, YOSHIYAMA Sadami, NISHIYAMA Atsushi, HAMAMOTO Yoshisuke

The ... international symposium on diagnostics and modeling of combustion in internal combustion engines ( 1 ) 29 - 29 2001年7月

記述言語：英語出版者・発行元：一般社団法人日本機械学会

Direct injection spark ignition (DISI) engines, which are able to achieve better thermal efficiency and higher output power simultaneously, have been developed. The DISI engine is operated unthrottled in an ultra-lean condition by distinctively stratifying the charge and by preparing a fuel-rich mixture around the spark plug. However, the effects of mixture inhomogeneity and simultaneous details of the flow field at the time of the spark on the combustion have not yet been clarified. In this research, the fundamental flame propagation and combustion characteristics of a stratified fuel-air mixture, similar to mixtures used in direct injection spark ignition (DISI) engines, were investigated. A swirling fuel-air mixture was produced in a disc-type combustion chamber by accelerating the mixture tangentially. Propane was injected into the center of the combustion chamber at an injection pressure of 0.3 MPa. The strong swirl combined with the gas injection created an axisymmetric fuel-rich mixture near the spark location and a lean mixture near the wall. The swirl, gas injection and spark timing changed the flow field, turbulence intensity, and inhomogeneity of the fuel-air mixture. The mixture was ignited at the center of the vessel. The fuel concentration distribution and the swirling flow field at the time of the spark were measured using LIF and LDV, respectively. Experimental tests were performed for various fuel distributions and different swirl flow at the ignition timing. Flame propagation and the combustion characteristics of an inhomogeneous fuel-air mixture are discussed using instantaneous flame images obtained from a high-speed video and the pressure history. Three main conclusions are drawn from this work. First, strongly swirling flow with gas injection at the center generates successive inhomogeneous fuel concentrations. By changing the period between gas injection and ignition, various gradients of inhomogeneous mixture concentrations and equivalence ratios can be obtained in the vicinity of the spark location. A stratified charge with an appropriate mixture near the spark location allows the flame to propagate and combustion to occur, even when an ultra-lean fuel-air mixture is used. Second, the stratified stoichiometric mixture in the vicinity of the spark location propagates more rapidly than in the homogeneous case with the same overall equivalence ratio, resulting in a higher rate of pressure increase and a shorter ignition delay time. Third, when stratified mixtures with the same pattern of fuel concentration but different turbulence intensities are considered, the main combustion period decreases with turbulence intensity at an overall equivalence ratio of 0.30, since the burning velocity also increases.

409 レーザ干渉法による二平行円板間における予混合火炎消炎過程の温度分布計測(エンジンIII)

冨田栄二, 河原伸幸, 臼田和也

講演論文集 2001 ( 39 ) 137 - 138 2001年2月

408 3.39μmにおける炭化水素系燃料の吸光係数に及ぼす圧力・温度の影響(エンジンIII)

冨田栄二, 河原伸幸, 吉山定見, 北川和典

講演論文集 2001 ( 39 ) 135 - 136 2001年2月

401 加圧雰囲気下における非定常燃料噴霧の挙動(エンジンI)

河原伸幸, 冨田栄二, 樫村亮

講演論文集 2001 ( 39 ) 121 - 122 2001年2月

Measurement of Transient Temperature of Gas Using Fiber Optic Heterodyne Interferometer

Kawahara, N, Tomita, E, Kamakura, H

Proc. of 3rd ASPACC 2001年1月

A fiber optical heterodyne interferometry system was developed to obtain high temporal resolution temperature histories of unburned and burned gases non-intrusively. The effective optical path length of the test beam changes with the gas density and corresponding changes of the refractive index. Therefore, the temperature history of the gas can be determined from the pressure and phase shift of the interference signal. The resolution of the temperature measurement is approximately 0.5 K, and is dependent upon both the sampling clock speed of the A/D converter and the length of the test section. A polarization-preserving fiber is used to deliver the test beam to and from the test section, to improve the feasibility of the system as a sensor probe. This optical heterodyne interferometry system may also be used for other applications that require gas density and pressure measurements with a fast response time, or a transient temperature record. Copyright © 2001 Society of Automotive Engineers, Inc.

DOI： 10.4271/2001-01-1922

ガンタイプバーナにおける噴霧のレーザ計測（噴霧クラスタと群燃焼構造）

河原伸幸, 池田裕二, 中島健

日本機械学会論文集Ｂ編 67 ( 655 ) 841 - 848 2001年

記述言語：日本語

A concept of "compound-cluster combustion" is proposed in order to investigate an applicability of group combustion theory to practical spray combustion, in which strong turbulent coherent vortex is formed and influenced spray behavior significantly. This turbulent coherent structure causes inhomogeneous droplet distribution and its population, and causes interphase exchange of properties and combustion under the effects of preferential interactions. In application of group combustion theory to practical spray combustion, these points were taken into account and phase Doppler measurement (PDA) data was analyzed : there are multiple clusters, characterized by their size and followabiliy (Stokes effect) ; clusters of different droplet sizes are produced at the same time in the flow field; the turbulent scale on cluster formation should be considered by the droplet's inter-arrival time statistics. In this research, PDA measurement with high sampling-rates and high validation- rates was carried out by optimizing the PDA set-up parameters. The integral length scale of each size cluster and the inter-arrival time statistics of the droplets can be obtained, based on the instantaneous droplet velocities as well as, but also Stokes' number, cluster size and inter-arrival time. The size-classified group combustion number is evaluated by the experimental data to demonstrate the applicability of group combustion theory. The interaction between the turbulent coherent vortex and small droplets of less than 30 μm generates essential clusters of the droplets and its combustion can be characterized by group combustion. The size of these clusters corresponds to the integral scale of the turbulent vortices. The effect of turbulent coherent structure on compound- cluster formation is examined and this effect is successfully evaluated by the Stokes effect.

DOI： 10.1299/kikaib.67.841

光ヘテロダイン干渉法によるガス温度変化計測

河原伸幸, 冨田栄二

光アライアンス Vol.12, No.12, pp.18-21 ( 12 ) 18 - 21 2001年

Hydrogen combustion and exhaust emissions ignited with diesel oil in a dual fuel engine

Eiji Tomita, Nobuyuki Kawahara, Zhenyu Piao, Shogo Fujita, Yoshisuke Hamamoto

SAE Technical Papers 2001年

記述言語：英語

Hydrogen is expected to be one of the most prominent fuels in the near future for solving greenhouse problem, protecting environment and saving petroleum. In this study, a dual fuel engine of hydrogen and diesel oil was investigated. Hydrogen was inducted in a intake port with air and diesel oil was injected into the cylinder. The injection timing was changed over extremely wide range. When the injection timing of diesel fuel into the cylinder is advanced, the diesel oil is well mixed with hydrogen-air mixture and the initial combustion becomes mild. NOx emissions decrease because of lean premixed combustion without the region of high temperature of burned gas. When hydrogen is mixed with inlet air, emissions of HC, CO and CO2 decrease without exhausting smoke while brake thermal efficiency is slightly smaller than that in ordinary diesel combustion. In particular, both smoke and NOx are almost zero and HC is low when the injection timing is significantly advanced although the engine operation becomes unstable. Copyright © 2001 Society of Automotive Engineers, Inc.

DOI： 10.4271/2001-01-3503

Effects of swirl turbulent flow field and inhomogeneous concentration field on combustion of fuel-air mixture in a constant volume vessel

Kawahara, N, Tomita, E, Nishiyama, A, Yoshiyama, S, Hamamoto, Y

Proc. of 5th COMODIA 2001 2001年

Combustion Characteristics of Stratified Fuel-Air Mixture with Swirl in a Constant-Volume Vessel

Nishiyama, A, Tomita, E, Kawahara, N, Hamamoto, Y, Yoshiyama, S

Proc. of 3rd ASPACC 2001年

808 定容容器内一次元層状燃料濃度場を伝播する火炎の観察(O.S.5-2 基礎燃焼)(O.S.5 次世代エンジンのための燃焼制御と新技術)

冨田栄二, 河原伸幸, 浜本嘉輔

講演論文集 5 ( 2 ) 247 - 248 2000年10月

802 加圧雰囲気下における非定常燃料噴霧の光学的計測(O.S.5-1 計測・解析)(O.S.5 次世代エンジンのための燃焼制御と新技術)

河原伸幸, 冨田栄二, 樫村亮

講演論文集 5 ( 2 ) 235 - 236 2000年10月

Effect of acoustic streaming on the mass transfer from a sublimating sphere

N Kawahara, AL Yarin, G Brenn, O Kastner, F Durst

PHYSICS OF FLUIDS 12 ( 4 ) 912 - 923 2000年4月

記述言語：英語出版者・発行元：AMER INST PHYSICS

The effect of the acoustic streaming on the mass transfer from the surface of a sphere positioned in an ultrasonic acoustic levitator is studied both experimentally and theoretically. Acoustic levitation using standing ultrasonic waves is an experimental tool for studying the heat and mass transfer from small solid or liquid samples, because it allows an almost steady positioning of a sample at a fixed location in space. However, the levitator introduces some difficulties. One of the main problems with acoustic levitation is that an acoustic streaming is induced near the sample surface, which affects the heat and mass transfer rates, as characterized by increased Nusselt and Sherwood numbers. The transfer rates are not uniform along the sample surface, and the aim of the present study is to quantify the spatial Sherwood number distribution over the surface of a sphere. The experiments are based on the measurement of the surface shape of a sphere layered with a solid substance as a function of time using a charge-coupled device (CCD) camera with backlighting. The sphere used in this research is a glass sphere layered with a volatile solid substance (naphthalene or camphor). The local mass transfer from the surface both with and without an ultrasonic acoustic field is investigated in order to evaluate the effect of the acoustic streaming. The experimental results are compared with predictions following from the theory outlined [A. L. Yarin, M. Pfaffenlehner, and C. Tropea, J. Fluid Mech. 356, 65 (1998); A. L. Yarin, G. Brenn, O. Kastner, D. Rensink, and C. Tropea, ibid. 399, 151 (1999)] which describes the acoustic field and the resulting acoustic streaming, and the mass transfer at the surface of particles and droplets located in an acoustic levitator. The results are also compared with the experimental data and with the theoretical predictions of Burdukov and Nakoryakov [J. Appl. Mech. Tech. Phys. 6, 51 (1965)], which are valid only in the case of spherical particles much smaller than the sound wavelength. Good agreement between experiment and the theory of Yarin is demonstrated. The time-averaged heat and mass transfer rates over a sphere surface are greatest at the sphere's equator and least at its poles in the experiment as predicted by the theory (the ultrasonic standing wave spans the vertical axis passing through the poles). The measured distribution of the mass transfer rate over the sphere surface also agrees with the theoretical predictions, which shows that in strong acoustic fields sublimation (or evaporation) results from the acoustic streaming. (C) 2000 American Institute of Physics. [S1070-6631(00)02104-8].

DOI： 10.1063/1.870347

314 二元燃料予混合圧縮着火ディーゼル機関における排気特性(エンジンシステムII)

冨田栄二, 河原伸幸, 浜本嘉輔, 藤田将語, 朴振宇

講演論文集 5 ( 1 ) 107 - 108 2000年2月

310 小型センサを使用した3.39μm赤外吸収法による燃焼室内燃料濃度変化の計測(エンジンシステムI)

冨田栄二, 河原伸幸, 吉山定見, 雑賀俊喜, 浜本嘉輔

講演論文集 5 ( 1 ) 99 - 100 2000年2月

Fuel Concentration Measurement near Spark-Plug in a Spark-Ignition Engine by 3.39m Infrared Laser Absorption Method

Tomita, E, Kawahara, N, Yoshiyama, S, Hamamoto, Y

Proc. of 22nd Task Leaders Meeting, Int. Energy Agency Executive Committee on Energy Conservation and Emission Reduction in Combustion 2000年

Transient Temperature Measurement of Unburned Gas Using Optic Heterodyne Interferometry

Kawahara, N, Tomita, E, Kamakura, H

10th Int. Symp. on Application of Laser Techniques on Fluid Mechanics 2000年

A Study on Hydrogen Combustion Ignited with Light Oil in a Dual Fuel Engine

Tomita, E, Kawahara, N, Hamamoto, Y, Zhen-Yu Piao, Fujita, S

4th JSME-KSME Thermal Engineering Conference 3 "3 - 415"-"3-420" 2000年

記述言語：英語出版者・発行元：日本機械学会

In diesel engines, there is a problem that both smoke and nitrogen oxide cannot be reduced simultaneously. There have been many studies on solving this problem. One of the solutions is the utilization of gaseous fuel. Gaseous fuel is inducted from an intake port and the combustion starts by injecting light oil. Hydrogen is considered as a future fuel without exhausting carbon dioxide. In this study, hydrogen was inducted from the intake port into the cylinder of a diesel engine and light oil was injected in the cylinder. The heat release rate was determined from the pressure history in the cylinder. The relation between the heat release rate and the exhaust emissions are discussed. As a result, when hydrogen is mixed with the inlet air, exhaust emissions such as smoke, hydrocarbon, CO, CO_2, and NOx are reduced simultaneously while brake thermal efficiency is slightly lower.

Flame Propagation of Inhomogeneous Fuel-Air Mixture with Swirl in a Constant-Volume Vessel

Kawahara, N, Tomita, E, Yoshiyama, S, Nishiyama, A, Hamamoto, Y

4th JSME-KSME Thermal Engineering Conference 3 "3 - 109"-"3-114" 2000年

記述言語：英語出版者・発行元：日本機械学会

The fundamental flame propagation and combustion characteristics of a stratified fuel-air mixture are investigated. Swirling turbulent flow with a rich fuel-air concentration is generated in a constant volume cylindrical vessel. The fuel concentration distribution and swirling flow field at the timing of the spark are measured using LIF and LDV, respectively. The mixture is ignited at the center of the vessel. Two main conclusions are drawn from this work. First, the strongly swirling flow with gas injection at the center generates successive inhomogeneous fuel concentrations. Various gradient and equivalence ratios in the vicinity of the spark location are obtained by changing the period between gas injection and ignition. Under a stratified charge condition, with an appropriate mixture near the spark location, the flame can propagate and combustion occurs, even with an ultra lean fuel-air mixture. Second, the stratified mixture with a stoichiometric mixture in the vicinity of the spark location propagates more rapidly than the homogeneous case with the same overall equivalence ratio. Both a higher rate of pressure rise and a shorter ignition delay time were achieved.

Measurements of the Combustion Characteristics of Compound Clusters in Pressure-Atomized Spray Flame

Kawahara, N, Ikeda, Y, Nakajima, T

37th AIAA Aerospace Sciences Meeting and Exhibit, AIAA Paper No.99-0210 1999年1月

© l999 American Institute of Aeronautics & Astronautics. In order to understand the combustion characteristics of droplet clusters consisting of a number of cluster sizes of i.nhomogeneous droplets, measurements of local chemiluminescence (OH, CH arid C,) were taken simultaneously with measurements of the droplets’ size and velocity in a spray flame stabilized by a recirculating flow. The limitations of using Cassegmin optics to measure chemiluminescence in actual spray flames was investigated. The Cassegrain optics developed were able to detect the local chemiluminescences of OK CH and C, in an actual spray flame. The intensity ratio of the time-averaged local chemiluminescences (&/OH) showed the local equivalence ratio of the fuel droplets in the spray flame. These five signals were analyzed statistically and spectrally, and finally combined to produce cross-correlation coefficients. These data can provide inhormation about the combustion characteristics of droplet clusters. The change in the burning mode of droplet clusters, from external group combustion to internal group combustion, was confirmed experimentally.

DOI： 10.2514/6.1999-210

Effects of different kinds of fuel and fuel equivalence ratio on flame structure of triple flame

Hiroshi Yamashita, Nobuyuki Kawahara, Nag Jung Choi

Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B 65 775 - 782 1999年1月

In order to clarify the effects of different kinds of fuel and fuel equivalence ratio on flame structure, a numerical simulation of triple flame developed in a co-flowing methane-air or hydrogen-air mixture and air stream was made taking into account the elementary chemical reaction mechanism. The following conclusions were reached: (1)The relation between the apparent burning velocity of the triple flame and the fuel equivalence ratio shows a similar tendency to that of the one-dimensional premixed flame of the corresponding fuel. However, the fuel equivalence ratio at which the apparent burning velocity is the largest is a little larger than that of the one-dimensional premixed flame. The apparent burning velocities are two and three times higher than that of the one-dimensional premixed flame for the methane-air or hydrogen-air mixture. ( 2 )The flame thrusts out forward in the downstream of the boundary between mixture and air stream, and a part of the flow is bent and forks out in this protruding flame so that a triple flame is originated ; this triple flame is composed of fuel rich and lean premixed flame branches and a diffusion flame branch. The change in shape of the convex part, caused by the effect of the one-dimensional premixed flame, is further promoted by the effect of hydrodynamic instability originated in the expansion brought about by heat release. A considerably strong diffusion flame branch exists almost in the center of the two premixed flame branches for the methane-air mixture, while a considerably weak diffusion flame branch approaches the fuel lean premixed flame branch for the hydrogen-air mixture. ( 3 )Near the fuel equivalence ratio at which the burning velocity of the one-dimensional premixed flame is the largest, the effect of the one-dimensional premixed flame becomes large and the fuel rich premixed flame advances and becomes vertical to the flow direction. As a result, the effect of hydrodynamic instability is weakened. Thus, both of these effects demonstrate that the fuel equivalence ratio at which the apparent burning velocity is the largest is a little larger than that of the one-dimensional premixed flame.

DOI： 10.1299/kikaib.65.775

Size-Classified Droplets Dynamics of Combusting Spray in Oil MW Oil Furnace

Nobuyuki Kawahara, Yuji Ikeda, Tsuyoshi Nakajima

Jaurnal of the Japan Society of Mechanical Engineering 65 ( 630 ) 790 - 797 1999年1月

The purpose of the present research is to investigate the aerodynamic characteristics of evaporating droplet near the burner where flame is hold by the recirculating flow and to characterize droplet aerodynamic response regarding follow or penetration and turbulent interaction with the surrounding air by classifing droplets. Aerodynamic characteristics of combusting spray were measured in a small industrial oil furnace by a phase Doppler anemometer. The size-classified technique was used together with the relative Reynolds number and the recombined two-dimensional size-classified droplet velocity. The results show that the two-dimensional behavior of a spray flame can be represented. The size-classified droplet technique can provide very useful information on droplet aerodynamics and dispersion. The follow/penetration characteristics of spray can be understood very well in consideration of the features of classified droplet in combustion condition. Larger droplets had a large mass and inertia, and thus could penetrate through the recirculation flow region. Consequently larger droplets form large luminous flame. On the other hand, smaller droplets were entrained by the turbulent air flow and played a role of flame-holder. In addition, the interaction between fuel droplets and air flow is a process that significantly affects flame-holding mechanism of spray flames.

DOI： 10.1299/kikaib.65.790

Development of Light-Collecting Probe with High Spatial Resolution Applicable to Randomly Fluctuating Combustion Fields

Akamatsu, F, Wakabayashi, T, Tsushima, S, Katsuki, M, Mizutani, Y, Ikeda, Y, Kawahara, N, Nakajima, T

Measurement Science and Technology 10 ( 12 ) 1240 - 1246 1999年1月

A high-luminosity-light-collection system for highly spatial detection of chemiluminescence of radical species in flames has been developed. The system, multi-colour integrated Cassegrain receiving optics (MICRO) is based upon a Cassegrain-type configuration, which implies that it employs only reflective components (in combination with an optical fibre for light collection). It provides therefore spherical-and chromatic-aberration-free detection, which is of importance for high-spatial-resolution measurements and for the simultaneous monitoring of signals in different wavelength regions from a given spatial volume. The effective light-collection volume has been estimated to be only 1.6 mm × 0.2 mm × 0.2 mm by ray-tracing techniques, which is more than three orders of magnitude smaller than that provided by a corresponding simple single-lens system and comparable to that of laser-based techniques, e.g. Doppler anemometry. The system is also easily aligned since the active probe volume can be visualized by sending in visible light through the system in the reverse direction. In order to demonstrate the performance of the system, OH-radical chemiluminescence in a Bunsen flame was monitored using MICRO and compared with the ion-current signal from a Langmuir probe with a minute sensor tip. A good correlation between the fluctuations in the two signals could be obtained, proving the high spatial and temporal resolution of the MICRO system.

DOI： 10.1088/0957-0233/10/12/316

Observation of Compound-Cluster Combustion in Pressure-Atomized Spray Flame

Kawahara, N, Ikeda, Y, Nakajima, T

Proc. of 2nd ASPACC 1999年

局所自発光計測による噴霧群燃焼構造の観察

河原伸幸, 池田裕二, 中島健

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 8 69 - 74 1999年

位相ドップラ法による噴霧火炎中の燃料油滴の粒径と速度の計測

河原伸幸

高温学会誌 24 ( 3 ) 102 - 110 1998年5月

Development of a Multi-Color light collection probe with high spatial resolution (1st Report, Evaluation of spatial resolution by Ray-Tracing Method)

Takashi Wakabayashi, Fumiteru Akamatsu, Masashi Katsuki, Yukio Mizutani, Yuji Ikeda, Nobuyuki Kawahara, Tsuyoshi Nakajima

Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B 64 ( 619 ) 925 - 930 1998年1月

Spot monitoring of radical chemiluminescence is especially useful for flame diagnostics, if the measuring control volume size can be clearly defined. However, a typical light collection system consisting of a spherical lens and a pinhole suffers from its wide and long control volume, as well as its significant chromatic aberration between UV and visible ranges in simultaneous multi-color measurement. In some cases, researchers were obliged to insert a control-volume limiting device into the flame for observing the local emission intensities of radical chemiluminescence. To resolve these problems, we have developed a light collection probe of Cassegrain type, which consists of a set of concave and convex mirrors combined with an optical fiber cable, and is free from both chromatic and spherical aberrations, which was named Multi-color Integrated Cassegrain Receiving Optics (MICRO). The spatial resolution was analyzed by the ray-tracing method, and the effective control volume size was estimated as 1.6 mm-long and 200 μn diameter, which is as small as that of LDA or PDA.

DOI： 10.1299/kikaib.64.925

Droplet dispersion and turbulent structure in a pressure-atomized spray flame

Nobuyuki Kawahara, Yuji Ikeda, Tsuyoshi Nakajima

35th Aerospace Sciences Meeting and Exhibit 1997年1月

© 1997, American Institute of Aeronautics and Astronautics, Inc. Investigation of the relationship between droplet dispersion and turbulent mixing in a pressure-atomized spray flame with a recirculation region was done. Time-resolved information of instantaneous droplet velocities and interarrival-time statistics of the droplet were obtained and examined in order to observe the turbulent mixing and follow/ penetration criteria. In order to observe the detailed structure of spray flames, the size and velocity of droplets instantaneously were measured by phase Doppler anemometer. The group combustion number was calculated by the experimental data in order to elucidate the actual aspects of group combustion. It was found that the turbulent coherent structures were contributed in order to form droplet clusters of small droplets under 30 µm because of its momentum, inertia and followability. The cluster dimensions obtained corresponded with the integral scale of turbulent vortex measured. While, large droplets penetrates strongly due to large momentum and less shear flow information along the spray cone so that group combustion characteristics could not be observed. The interaction and its relation of turbulent scale and group combustion cluster was discussed with measured data for a practical oil burner of 0.1MW.

Fuel droplet dynamics and dispersion of practical twin-fluid atomizer for oil furnace

Y. Ikeda, N. Tsuchimoto, N. Kawahara, T. Nakajima

International Journal of Fluid Mechanics Research 24 ( 1-3 ) 138 - 148 1997年

記述言語：英語出版者・発行元：Begell House Inc.

The purpose of this study is to investigate fuel droplet dispersion and mixture formation in a practical twin-fluid atomizer for a practical oil furnace of 1 MW. In this experiment, droplet size, velocity and dispersion data were measured to show two-dimensional droplet velocity vectors using phase Doppler technique (PDA/PDPA). Fuel droplet dynamics and spray characteristics are discussed by two-dimensional size-classified droplet vector and their slip velocities vector. The spray dynamics is investigated by not only Sauter mean diameter but also each size-classified velocity. The results showed that the size classified technique was suitable and the strong penetration of small droplet near nozzle and the much entrainment flow were yielded at the middle of the jet plane. The injection pressure was varied to show the spray characteristics changes for different conditions.

DOI： 10.1615/InterJFluidMechRes.v24.i1-3.140

Flame holding in a gun-type oil burner (fluctuation characteristics and concentration variation)

Yuji Ikeda, Nobuyuki Kawahara, Tsuyoshi Nakajima

Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B 62 ( 596 ) 1599 - 1607 1996年1月

Three dimensional measurements of velocity and gas flux measurements of O2, CO2 flux near burner of oil furnace were demonstrated to show a flame holding mechanism and fluctuation characteristics. The use of convective flux in flame was not accurate but found to be applicable in whole combustion region in a furnace. Two pairs of recirculating flow region rotated in swirl direction due to the slit flow and its timescale was about 5-10 msec. The timescale of turbulence and CO, CO2 gas variation were compared in order to show the flame holding mechanism in a transparent evaporating region. The comparison results show that the timescale of turbulence and chemical species fluctuation were the same order.

DOI： 10.1299/kikaib.62.1599

Combusting Flow Simulation in an oil Furnace

Yuji Ikeda, Nobuyuki Kawahara, Tsuyoshi Nakajima

Jaurnal of the Japan Society of Mechanical Engineering 62 ( 598 ) 2481 - 2489 1996年1月

Combusting flow simulations in an oil furnace (0.1 MW) were carried out in order to investigate droplet behavior and the flame-holding mechanism. Measurements made by a phase Doppler anemometer were also examined to elucidate the followability characteristics in recirculation flow. The results show that a droplet under 30 microns can follow the flow but a droplet over 50 microns penetrates. The use of connective flux of O2and CO2both in the flame and the entire furnace was examined and the results demonstrated that it was very useful to show the self-recirculating flow in furnaces.

DOI： 10.1299/kikaib.62.2481

Flux Measurements of O₂, CO₂ and No in Oil Furnace

Yuji Ikeda, Nobuyuki Kawahara, Tsuyoshi Nakajima

Journal of the Japan Society of Mechanical Engineering 61 ( 581 ) 332 - 338 1995年1月

記述言語：日本語出版者・発行元：The Japan Society of Mechanical Engineers

The flow velocity measurements and flux measurements of gas species of O2, CO2and NO in an oil furnace were carried out. The velocity profiles in combustion and noncombustion were measured by the developed LDV, and the results show that the reversing flow regions for both cases were located at the same place and their volumes were almost equal. The comparisons of measured concentration and flux obtained using velocity and temperature were performed in spray combustion. The results show that there is little difference in the flame region but a large discrepancy outside of the flame region. The generated gas species in the flame and its convection outside of the flame were discretized, and the application of flux in spray combustion research was found to be very useful and effective. © 1995, The Japan Society of Mechanical Engineers. All rights reserved.

DOI： 10.1299/kikaib.61.332

Flux measurements of O2, CO2 and NO in an oil furnace

Yuji Ikeda, Nobuyuki Kawahara, Tsuyoshi Nakajima

Measurement Science and Technology 6 ( 6 ) 826 - 832 1995年

記述言語：英語

The flow velocity measurements and flux measurements of the gas species O2, CO2 and NO in an oil furnace were carried out. The velocity profiles in combustion and non-combustion were measured by the developed laser Doppler velocimeter, and the results show that the reversing flow regions for both cases were located at the same place and their volumes were almost equal. The comparisons of measured concentration and flux obtained using velocity and temperature were performed in spray combustion. The results show that there is little difference in the flame region but a large discrepancy outside the flame region. The generated gas species in the flame and their convection outside the flame were discretized, and the application of flux in spray combustion research was found to be very useful and effective.

DOI： 10.1088/0957-0233/6/6/019

ガンタイプバーナにおける噴霧挙動の数値解析

河原伸幸, 池田裕二, 中島健

微粒化シンポジウム講演論文集 = Symposium (ILASS-Japan) on Atomization 4 220 - 225 1995年

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