• Title/Summary/Keyword: 고속도 화염사진

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A Study on Diesel Spray and Flame by Rapid Compression Machine (급속압축장치에 의한 디이젤 분무 , 화염의 연구)

  • 안수길
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.19 no.1
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    • pp.40-45
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    • 1983
  • The paper describes an experimental investigation of axisymmetric diesel spray and flame which is held in rapid compression machine (RCM) with electromagnetic single injection nozzle. The axisymmetric diesel spray and flame are taken with high speed photograph and analysis it with image processor. The data presented include fuel concentration of spray, flame temperature, soot concentration of flame in axial and radial direction at a moment and compared it with each other.

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The Effect of Combustion Process by Intensifying the Air Flow in Combustion Chamber of D.I. Diesel Engine (직접분사식 디젤기관의 연소실내 공기유동강화가 연소과정에 미치는 영향)

  • Bang, Joong-Cheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.5
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    • pp.153-159
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    • 2007
  • The performance of a direct-injection type diesel engine often depends on the strength of air flow in the cylinder, shape of combustion chamber, the number of nozzle holes, etc. This is of course because the process of combustion in the cylinder was affected by the mixture formation process. In the present paper, high speed photography was employed to investigate the effectiveness of holes penetrated from the bottom of cavity wall to piston crown for some more useful utilization of air. The holes would function to improve mixing of fuel and air by the increase of air flow in the cylinder. The results obtained are summarized as follows, (1) Activated first of the combustion by shorten of ignition timing and rapid flame propagation (2) Raised the combustion peak pressure, more close to TDC the formation timing of peak pressure.

The Study for Improving the Combustion in a Common-rail Diesel Engine using Swirl Groove Piston (Swirl Groove Piston에 의한 커먼레일 디젤기관의 연소성 향상에 관한 고찰)

  • Bang, Joong-Gheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.6
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    • pp.145-151
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    • 2010
  • The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several grooves with inclined plane on the piston crown to generate swirl during the compression and expansion strokes in the cylinder in order to improve the atomization of fuel. The other is a toroidal piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.

Fundamental Experiments of a Compression Ignition Engine Using Gaseous Fuel (가스체 연료를 사용하는 압축착화기관에 관한 기초적 연구)

  • ;太田 幹郞
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.2
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    • pp.147-157
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    • 1996
  • Natural gas is gaining more attraction as a future fuel in particular both for environmental protection and energy conservation. In order to bring about more widespread use of gaseous engines, the technology capable of achieving output and efficiency performance equivalent to that of diesel engines needs to be developed. In the present paper, the requirements of the pilot torch from pre-chamber for ensuring ignition and promoting combustion are discussed by means of taking high-speed flame photography and system can run with leaner mixture of various fuels comparing to the electric plug ignition system cause the ignition delay period ignited with the torch and the combustion period are very short in spite of changing A/F of gaseous fuels in the main chamber. However, the suitable piston-cavity design for the use of lower-hydrocarbon fuels such as propane and butane must be discussed increasingly in the mear future.

Fundamental study on combustion characteristics of methanol fuel in a constant volume chamber (정적연소기를 사용한 메탄올의 연소특성에 관한 연구)

  • 이태원;이중순;정성식;하종률
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.2
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    • pp.389-396
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    • 1994
  • It is very important to clarify the ignition and flame propagation processes of methanol fuel in the Spark-ignition engine. High speed Schlieren photography and pressure trace analyses were used to study on combustion characteristics of methanol fuel in a constant volume chamber. Methanol-air mixtures equivalence rations from lean limit to 1.4 were ignited at initial pressure (0.1, 0.3, 0.5 MPa), temperature (313 343, 373 K) and ignition energy (40, 180 mJ). As the result of this study, we verified the characteristics such as ignition delay, effective thermal efficiency, flame propagation velocity, lean limit, ignitability and combustion duration. Obatained results are as follows. (1) The time to 10% reach of maximum pressure was 40-50% of the total combustion duration for this experimental condition hardly affected by equivalence ratio. (2) The Effective thermal efficiency, as calculated from maximum pressure was the highest when the mixture was slightly lean $({\phi} 0.8-0.9)$ and maximum pressure was the highest when the mixiture was slightly rich $({\phi} 1.2-1.2).$

A Study on Combustion Process of Biodiesel Fuel with Pilot Injection in a Common-rail Diesel Engine (파일럿분사에 의한 바이오디젤유의 연소과정에 관한 연구)

  • Bang, Joong-Cheol;Kim, Sung-Hoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.3
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    • pp.146-153
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    • 2011
  • American NREL (National Renewable Energy Laboratory) reported that BDF20 could reduce PM, CO, SOx, and cancerogenic matters by 13.6%, 9.3%, 17.6%, and 13% respectively, compared to diesel fuel. BDF20 has been being tested on garbage trucks and official vehicles at Seoul City, which is positive on air environment, but negative on combustion by higher viscosity in winter season. This study investigated the combustion characteristics by applying pilot injection for improving the deterioration of combustibility caused by the higher viscosity of the BDF20 with the combustion flames taken by a high-speed camera and the cylinder pressure diagram. A 4-cycle single-cylinder diesel engine was remodeled to a visible 2-cycle engine taking the flame photographs, which has a common-rail injection system. The test was done laboratory temperature at $5{\sim}6^{\circ}C$. The results obtained are summarized as follows, (1) In the case of without pilot injection, the flame propagation speed was slowed and the maximum combustion pressure became lower. The phenomena became further aggravated as the fuel viscosity gets higher. (2) In the case of with pilot injection, early stage of combustion such as rapid ignition timing and flame propagation was activated since intermediate products formed by pilot injection act as a catalyst for combustion of main fuel.

A Study on Combustion Process of Biodiesel Fuel using Swirl Groove Piston (Swirl Groove Piston에 의한 바이오 디젤연료의 연소과정에 관한 연구)

  • Bang, Joong-Cheol;Kim, Sung-Hoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.1
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    • pp.105-113
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    • 2009
  • The performance of a direct-injection type diesel engine often depends on the strength of swirl or squish, shape of combustion chamber, the number of nozzle holes, etc. This is of course because the combustion in the cylinder was affected by the mixture formation process. In this paper, combustion process of biodiesel fuel was studied by employing the piston which has several grooves with inclined plane on the piston crown to generate swirl during the compression stroke in the cylinder in order to improve the atomization of high viscosity fuel such as biodiesel fuel and toroidal type piston generally used in high speed diesel engine. To take a photograph of flame, single cylinder, four stroke diesel engine was remodeled into two stroke visible engine and high speed video camera was used. The results obtained are summarized as follows; (1) In the case of toroidal piston, when biodiesel fuel was supplied to plunger type injection system which has very low injection pressure as compared with common-rail injection system, the flame propagation speed was slowed and the maximum combustion pressure became lower. These phenomena became further aggravated as the fuel viscosity gets higher. (2) In the case of swirl groove piston, early stage of combustion such as rapid ignition timing and flame propagation was activated by intensifying the air flow in the cylinder. (3) Combustion process of biodiesel fuel was improved by the reason mentioned in paragraph (2) above. Consequently, the swirl grooves would also function to improve the combustion of high viscosity fuel.

A Study on NOx Pollutant Reduction and Combustion Characteristics of Impinging-Jet-Flame Combustion Process( II ) (대향분출염(對向噴出焰) 연소방법(燃燒方法)에 의(依)한 NOx 생성저감(生成低減)과 연소특성(燃燒特性) 연구(硏究)( II ))

  • Jeung, I.S.;Cho, K.K.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.2
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    • pp.124-131
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    • 1994
  • 자동차엔진의 연소과정에 상사하는 밀폐정적연소실을 주연소실과 대향 2개 부연소실로 분할하고 오리피스로 연결하였다. 이때 부연소실로부터 주연소실로 분출하는 대향분출염 연소에 의한 질소산화물 배출저감특성을 연소방식, 연소실형상 그리고 연료종류를 변경한 수종의 실험으로 조사하였다. 질소산화물농도, 연소실 최고압력, 화염전파과정의 고속도슐리렌사진 가시화를 수행한 결과, 대향분출염 연소방식을 도입하연 연소실의 중앙부공간이 상대적으로 넓은 경우에 고부하운전과 동시에 질소산화물의 배출량도 저감할 수 있었다. 그러나 연료의 종류는 질소산화물생성에 매우 영향이 적었다.

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The effect of air and spray turbulence in a D.I. diesel engine on the flame progress (直接噴射式 디이젤機關의 燃燒室形狀과 火焰의 發達)

  • ;;Ohta, Motoo
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.1
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    • pp.44-52
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    • 1987
  • For the favorable performance of a D.I. diesel engine, it is important to improve the mixture formation process and the ensuing early stage of combustion process. In the present paper, high speed photography was employed to investigate the effectiveness of a cavity digged in a piston crown for some more useful utilization of air. The cavity would function to improve mixing of fuel and air by the increase of turbulence of air and by the impingement of fuel spray on the cavity wall. The results obtained are summarized as follows: (1) From an aspect of thermal efficiency, it is effective to inject the spray tangentially to the cavity wall to enlarge the area of spray evaporation. (2) some deductions obtained from previous investigations using a hot air stream duct are supported by the present results. For example, it is effective for the quick development of flames throughout the combustion chamber to mix the evaporated fuel of main spray with the intermediates brought about by the early stage of combustion of the preceded auxiliary fuel spray.

The Effect of Air and Spray Turbulence on the Progress in a D.I. Diesel Engine(II)-Combustion Chamber Design for the Use of Emulsified Diesel Oil with Water Particles- (직접분사식 디젤기관의 연소실 형상과 화염의 발달 (2)-유화액연료용 연소실의 형상-)

  • ;;Ohta, Motoo
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.11
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    • pp.3054-3062
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    • 1995
  • Recently, the improvement of fuel economy and the reduction of exhaust smoke and NOx have been successfully achieved by supplying diesel engines with emulsified diesel oil with water particles. In the present paper, the difference between the combustion of injected emulsified fuel and that of diesel oil spray is clarified by means of taking high-speed and color photographs of the flames in the engine cylinder. As the results, the two kinds of fuels show different combustion behavior each other in the growth of initial flame and in the termination of combustion process in the cylinder. Then, suitable combustion chamber design for the use of emulsified fuel is discussed on the basis of experimental data for various distribution of spray in different kinds of piston cavities. Some methods of clearing troubles caused by emulsified fuel injection are also discussed on the basis of performance tests with a remodeling test engine.