• Title/Summary/Keyword: 직접분사식

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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 Flame Characteristics by Combustion Chamber Shape in 2 Stroke D.I. Diesel Engine -The Influence of Scavenging Pressure and Scavenging Temperature- (직접분사식 2행정 디젤기관의 연소실 형상에 따른 화염 특성 -소기압력 및 소기온도의 영향을 중심으로-)

  • 최익수;방중철
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.1
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    • pp.55-63
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    • 2003
  • In a diesel engine, air-fuel mixture formation and ignition delay period have great influence on the performance of engine. Their main factors are combustion chamber shape, fuel injection system. air volume, air flow and so on. So, the combustion process in the cylinder is complex because of many factors which have direct and indirect effects on it. In this study, we take into consideration of scavenging pressure and scavenging temperature that are hewn as the main factor to the combustion process of two-stroke D.1. diesel engine. It is taken a picture of the combustion flame process for combustion chamber of re-entrant type and cylindrical type. So, it is applied to the basis data of combustion chamber design from an image analysis.

Engine Performance and Exhaust Emissions Characteristics of DI Diesel Engine Operated with Neat Dimethyl Ether (순수 DME의 직접분사식 디젤기관의 성능 및 배기가스 특성)

  • Pyo, Young-Dug;Lee, Young-Jae;Kim, Gang-Chul;Kim, Mun-Heon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.5
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    • pp.589-595
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    • 2003
  • DME(Dimethyl ether) is an oxygenated fuel with a octane number higher than that of diesel oil. It meets the ULEV emission regulation and reduces the smoke to almost zero when used in a diesel engine. In the present study, engine performance and exhaust emissions were investigated with a conventional DI diesel engine which has a jerk type injection pump. Test results showed that the power with DME were almost same as that of pure diesel oil, and the brake thermal efficiency increased a little. Also, smoke index from DME engine showed nearly zero level, but NO$_{x}$ was increased compare to diesel oil.

A study on the characteristics of soots formation in spray flame for DI diesel engine (직접분사식 디젤기관의 화염 속에서 생성되는 그을음의 특성에 관한 연구)

  • 라진홍;안수길
    • Journal of Ocean Engineering and Technology
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    • v.10 no.4
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    • pp.128-140
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    • 1996
  • To analyze a formation process of the soots in spray flame in the combustion chamber, an optically accessible DI Diesel engine was used for visualization. The images of the flames and soots were visualiaed with high speed camera by Schlieren method and Light extinction method. The spray flame and soot images on the films were analyzed at the various engine operating conditions. Soot distributed widely in spray flame and its concentration was about $100g/m^3$ at the position close by nozzle tip of spray flame region, however it decreased below $20g/m^3$ at the corner of combustion chamber due to soot oxidation.

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Simulation of Spray Impingement and Fuel Film Formation in a Direct Injection Diesel Engine (직접분사식 디젤엔진에서의 분무충돌과 연료액막형성 해석)

  • Kim, Man-Shik;Min, Kyoung-Doug;Kang, Bo-Seon
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.919-924
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    • 2000
  • Spray impingement model and fuel film formation model were developed and incorporated into the computational fluid dynamics code, STAR-CD. The spray/wall interaction process were modelled by considering the change of behaviour with surface temperature condition and fuel film formation. We divided behaviour of fuel droplets after impingement into stick, rebound and splash using Weber number and parameter K. Spray impingement model accounts for mass conservation, energy conservation and heat transfer to the impinging droplets. A fuel film formation model was developed by Integrating the continuity, the Navier-Stokes and the energy equations along the direction of fuel film thickness. The validation of the model was conducted using diesel spray experimental data and gasoline spray impingement experiment. In all cases, the prediction compared reasonably well with experimental results. Spray impingement model and fuel film formation model have been applied to a direct injection diesel engine combustion chamber.

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An Experimental Study of In-Cylindeer Flow Characteristics of a High Speed Direct Injection Diesel Engine (고속 직접분사식 디젤엔진의 실린더내 유동특성에 관한 실험적 연구)

  • 정경석
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.3
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    • pp.22-30
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    • 1996
  • In-cylinder flow of a purpose-built small HSDI Hydra Diesel engine was investigated by laser Doppler velocimetry(LDV) during induction and compression processes. The flow was quantified in terms of ensemble-averaged axial and swirl velocities, normalized by the mean piston speed, at a plane located 12mm from the cylinder head and corresponding to the mid-plane of the diametrically-opposed quartz windows at an enigne speed of 1000rpm. The formation of toroidal vortices during the intake process and the evolution and decay of swirl motion during the compression process were observed. Turbulence at around TDC of compression became homogeneous and isotropic.

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An Investigation on a Cause of Cycle Variation in Hydrogen Fueled Engine with Direct Injection (직접분사식 수소기관의 사이클변동 원인해석에 관한 연구)

  • Kim, Y.Y.;Lee, Jong T.
    • Transactions of the Korean hydrogen and new energy society
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    • v.13 no.3
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    • pp.233-241
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    • 2002
  • To achieve hydrogen power system with high performance and stable operation, the COVimep of hydrogen fueled engine with direct injection was evaluated with the change of engine speed, injection timing, air-fuel equivalence ratio and spark timing. And the cause of cycle variation was analyzed by using coefficient of variation in combustion period defined in this study. the results showed that the cycle variation of hydrogen fueled engine is mainly dependent on the early combustion period.

The Effect of Auxiliary use LPG on the Performance of a D.I. Diesel Engine (LPG를 보조적으로 사용한 직접분사식 디젤기관의 성능에 관한 연구(II))

  • Bang, Joong-Cheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.3
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    • pp.150-156
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    • 2006
  • Recently, the tightening of available crude oil supplies has resulted in the development of intense consciousness for saving fuels. At the same time, some research programs have been launched to secure substitute energy sources for petroleum-derived fuels, and to reduce unhealthy products, such as CO, HC, NOx and smoke. To keep up with these trends in society, the regulation affecting diesel smoke may be greatly strengthened in a short time. In not too distant future, LPG and LNG are the most hopeful substitute fuels for automobile and truck uses. This paper discusses how to use such gaseous fuels in a diesel engine, and how to find out introducing these fuels affect the engine performance.

Some Considerations of the Ignition Delay Period in D.I Diesel Engine (직접분사식 디젤기관의 착화지연기간에 대한 고찰)

  • Bang, Joong-Cheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.2
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    • pp.97-103
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    • 2010
  • The four combustion stages in a diesel engine have close correlation among them. Especially, the ignition delay period has significant effect on the following combustion stage. And the period is also one of inevitable combustion processes in the diesel engine. For example, the diesel knocking is a well-known phenomenon due to the long ignition delay period. The interval of the ignition delay period is affected by the mixture formation process in the cylinder. However, in the case of the D.I. diesel engine, the available duration to make the mixture formation of air-fuel is very short. In addition, the means of the mixture formation mainly depends on the injection characteristics and properties of the fuel. 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 study, using the visible engine, we measured the ignition delay period by photo sensor which detect occurrence of flame and presented the factors of the injection characteristics such as kinds of injection system, the injection pressure and the injection timing. The relation between the ignition delay period and cylinder pressure diagram which was concurrently obtained was also estimated.

An Experimental Study on Electronic Injection System for Pollutant Reduction in a DI Diesel Engine (직접분사식 디젤엔진에서의 공해저감을 위한 전자분사 시스템에 관한 실험적 연구)

  • ;;;;Ale
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.1
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    • pp.9-14
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    • 1997
  • The pump-pipe-injector system is that most commonly used type of injection equipment for diesel engines. In this study, a new electromagnetic fuel injection system was designed and carried out the experiment of single cylinder direct injection(DI) diesel engine. This system do not need the cam shaft for fuel injection. The effects of the injection timing on the combustion process and emission were investigated. The results are that 1) atomization was improved, 2) combustion pressure was increased and ignition delay became shorter than before, 3) Low smoke level guarantee with more advanced injection timing without abnormal combustion but NOX concentration was increased as the injection time advanced.

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