• Title/Summary/Keyword: 분사 지연

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An Experimental Study on the Emission Characteristics of GTL Fuel with Injection Timings in CRDi Single Cylinder Engine (커먼레일 단기통 엔진에서 GTL 연료의 분사시기 변화에 따른 배출물 특성)

  • Kim, Byoung-Jun;Lee, Yong-Gyu;Choi, Kyo-Nam;Jeong, Dong-Soo;Cha, Kyung-Ok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.1
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    • pp.181-187
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    • 2008
  • Recently, alternative fuels are drawing more attentions due to the increasing need for lower emission characteristics and fuel consumption rate in automotive engines. The GTL(gas to luquid) is the one of most favored candidates. It has higher cetane number(more than 75) and almost negligible sulphur and aromatic contents. Therefore, enhanced emission characteristics are expected even in the application in diesel engines without any modification. In this study, the cylinder pressure and heat release, emission characteristics with fuel injection timings are compared between diesel and GTL fuel in the single cylinder diesel engine. Noticeable reduction in PM, THC and CO emission are observed due to lower sulphur and aromatic contents in GTL. Also, the ignition delay decreased due to higher cetane number of GTL, which slightly decreased the amount of NOx emissions. With the retards of main injection timing, NOx decreases more for the case of GTL, while the level of THC and CO emissions still remains lower than the case of diesel. Therefore, there is much room for the control of injection timing for NOx reduction without sacrificing THC and CO emissions. With the retards of main injection timing, Small size distribution of PM became lager and there amount increased. But from all conditions, size distribution of PM for the case GTL was lower than Diesel.

STUDY ON HEAT RELEASE RATE BY COMBUSTION IN DIESEL ENGINE (Diesel기관의 연소에 의한 열발생율의 연구)

  • AHN Soo Gil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.8 no.3
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    • pp.150-156
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    • 1975
  • This paper dealt itself with the relation of the heat release rate with crank angle in combustion process by adjusting the injection time, injection amount and engine speed of diesel engine. The result of test were obtained by analyzing indicator diagram of KUBOTA 2LKE diesel engine, where the indicator was used Tertronix oscilloscope. The combustion period of diesel engine is composed of premixed burning time and combustion controlled time. The larger the premixed burning region, the higher efficiency was obtained with the higher maximum pressure than at the time of the normal smooth operation. The longer the combustion controlled time, the lower the maximum pressure than the period of the normal operation, but the efficiency was decreased. The region of premixed burning was principally controlled by injection delay, but combustion controlled time was affected when oxygen and fuel were mixed. Efficiency of engine was increased at the time of earlier injection time under the constant injection amount, and engine speed, but the pressure increasing was observed higher than the efficiency increasing.

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Study on Performance of an Fuel Pressure Regulator under Failure Condition in an Electric Control Diesel Engine (전자제어 디젤엔진의 연료압력 레귤레이터 고장에 따른 진단 및 성능 연구)

  • Kim, Tae-Jung;Cho, Hong-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.3
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    • pp.1677-1683
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    • 2015
  • To cope with exhaust gas regulation, Diesel engine applied to electronic control system. As it accurately regulated the injected fuel mass and the fuel efficiency and the output are increased but the noise and the vibration are decreased. In order to keep the performance of Electronic Diesel Control System, it is important to accurately control the fuel pressure. However, when the regulator of fuel pressure is not controlled properly, the failure phenomenons(starting failure, staring delay, accelerated failure, engine mismatch et al.) occur because the fuel pressure is not stabilize. In this study, effects on a fuel pressure, engine rotating speed according to the control rate of fuel-pressure regulator are investigated in order to analyzed the performance variation with failure of fuel-pressure regulator. As a result, when the control rate of a fuel-pressure regulator is 4%~6% lower than that of standard condition, the variation of engine's rpm and return fuel flow is increased, and the abnormal condition was occurred. Besides, it is possible to diagnose the failures on fuel-pressure regulator under these conditions.

Spray Characteristics of Water-Gel Propellant by Impinging Injector (Water-Gel 모사 추진제의 충돌 분무 특성 연구)

  • Hwang, Tae-Jin;Lee, In-Chul;Kim, Sang-Sun;Koo, Ja-Ye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.11-14
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    • 2009
  • The implementation of gelled propellants systems offers high performance, thrust-control, energy management of propulsion, storability, and high density impulse of solid propulsion. Present study focused on the spray behavior of liquid sheets formed by impinging jets of non-Newtonian liquids which are mixed by Carbopol 941 0.5%wt. The results are then compared with experiments conducted on spray images formed by impinging jets concerning with air-blast effect at center orifice. When gel propellants are injected by doublet impinging jets at low pressure, closed rim pattern shape appeared. As increasing air mass flow rate(decreasing GLR), spray breakup and atomization phenomenon better improved and spray structure instabilities for the effect of air-blast are also increased.

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A Study on the Characteristics of Ignition and Combustion, in a Diesel Spray Using Multi-Component Mixed Fuels (다성분 혼합연료를 이용한 디젤분무의 착화연소특성에 관한 연구)

  • Yoon, Jun-Kyu;Lim, Jong-Han
    • Journal of Energy Engineering
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    • v.16 no.3
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    • pp.120-127
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    • 2007
  • The purpose of this study is experimentally to analyze that the fuel mass fractions of multi-component mixed fuels have an effect on the characteristics of spray ignition and combustion under the ambient conditions of diesel combustion fields. The characteristics of ignition and combustion were investigated by chemiluminescence images and direct photography. The experiments were conducted in the RCEM(rapid compression expansion machine) with optical access. Multi-component fuels mixed with i-octane, n-dodecane and n-hexadecane are injected in RCEM by the electronic control of common rail injector. Experimental conditions set up 42, 72 and 112 MPa in injection pressure, 700, 800 and 900 K in ambient gas temperature. The results show that the ignition delay was dependent on high cetane number. In case of low ambient temperature, the more low boiling point fuels were mixed, the lower luminance regime had a remarkable effect and also shortened diffusion combustion by increasing heat release rate.

The Effect of T90 Temperature on Exhaust Emissions in Low-temperature Diesel Combustion (저온 디젤 연소에서 T90 온도가 배기가스에 미치는 영향)

  • Han, Man-Bae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.4
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    • pp.72-77
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    • 2011
  • This study is to investigate the effect of the distillation temperature in ultra low sulfur diesel fuel on exhaust emissions in the low-temperature diesel combustion with 1.9L common rail direct injection diesel engine. Low temperature diesel combustion was achieved by adopting an external high EGR rate with a strategic injection control. The engine was operated at 1500 rpm 2.6 bar BMEP. The 90% distillation recovery temperature (T90) was $270^{\circ}C$ and $340^{\circ}C$ for the respective cetane number (CN) 30 and 55. It was found that there exists no distinctive discrepancy on exhaust emissions with regards to the different T90s. The high CN (CN55) fuels follow the similar trend of exhaust emissions as observed in CN30 fuels' except that high T90 fuel (CN55-T340) produced higher PM compared to low T90 fuel (CN55-T270). This may come from that high T90 plays an active role in aggravating the degree of fuel-air mixture preparedness before ignition.

Auto-ignition Characteristics of Paraffin and PE Hybrid Rocket with $H_2O_2$ Catalytic Decomposition (과산화수소 촉매 분해를 이용한 파라핀 및 PE 하이브리드 로켓의 자연 점화 특성)

  • An, Sung-Yong;Jin, Jung-Kun;Jung, Eun-Sang;Kwon, Se-Jin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.13 no.5
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    • pp.48-56
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    • 2009
  • The auto-ignition tests of hybrid rockets with the concentrated hydrogen peroxide as an oxidizer were presented. Auto-ignition was successfully demonstrated by injecting decomposed gases from $H_2O_2$ into paraffin or polyethylene fuels. In addition, restart and instant ignition were realized with this rocket. For stable combustion, a higher $L^*$ value was required for the paraffin combustion compared with PE. On the other hand, much faster response time was demonstrated in case of a paraffin, which was 13 and 30 ms at ignition delay and rise time respectively.

Auto-ignition Characteristics of Paraffin and PE Hybrid Rocket with $H_2O_2$ Catalytic Decomposition (과산화수소 촉매 분해를 이용한 하이브리드 로켓 자연 점화)

  • An, Sung-Yong;Jin, Jung-Kun;Jung, Eun-Sang;Kwon, Se-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.499-502
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    • 2009
  • The auto-ignition tests of hybrid rockets with the concentrated hydrogen peroxide as an oxidizer were presented. Auto-ignition, restartability, and instant ignition were successfully demonstrated by injecting decomposed gases from $H_2O_2$ into paraffin or polyethylene fuels. In addition, much faster response time was demonstrated in case of a paraffin, which was 13 and 30 ms at ignition delay and rise time respectively.

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Effects of Aspect Ratio on Combustion Characteristics in Diesel Engine (연소실 형상비가 디젤기관의 연소특성에 미치는 영향)

  • Kwon, S.I.;Kwon, J.B.;Kim, H.S.
    • Journal of ILASS-Korea
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    • v.3 no.3
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    • pp.23-32
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    • 1998
  • The effect of reentrant type bowl geometry on combustion characteristics was investigated in a D.I. diesel engine. The main factor was the aspect ratio (Bowl Diameter / Bowl Depth) of bowl of combustion chamber, and the cylinder pressure, engine performance and emissions of the engine using the 4 kinds of the combustion chamber were meadured. Also, the combustion characteristics compared of the experimented and the calculated values which is used by the Hiroyasu's combustion model. The results are as follows; The effect of $d_c/H$ on ignition delay period are small. The smoke is corerelated to the heat release of the premixed and the diffusion combustion, i.g, the smoke decreased by decreasing the premixed combustion or increasing the diffusion combustion on cumulative heat release. The premixed combustion process has more effect than the diffusion combustion on smoke. The formal tendency of $d_c/H$ on engine performance has not appear.

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An Experimental Study on Diesel Spray Dynamics and Auto-Ignition Characteristics to use Rapid Comperssion Machine (RCM을 이용한 디젤 분무 거동 및 자발화 특성에 관한 실험적 연구)

  • Ahn, J.H.;Kim, H.M.;Shin, M.C.;Kim, S.W.
    • Journal of ILASS-Korea
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    • v.8 no.3
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    • pp.33-40
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    • 2003
  • The low-emission and high-performance diesel combustion is an important issue in the combustion research community, In order to understand the detailed diesel flame involving the complex physical processes, it is quite desirable to diesel spray dynamics, auto-ignition and spray flame propagation. Dynamics of fuel spray is a crucial element for air-fuel mixture formation, flame stabilization and pollutant formation, In the present study, the diesel RCM (Rapid Compression Machine) and the Electric Control injection system have been designed and developed to investigate the effects of injection pressure, injection timing, and intake air temperature on spray dynamics and diesel combustion processes, In terms of the macroscopic spray combustion characteristics, it is observed that the fuel jet atomization and the droplet breakup processes become much faster by increasing the injection pressure and the spray angle, With increasing the cylinder pressure, there is a tendency that the of spray pattern in the downstream region tends to be spherical due to the increase of air density and the corresponding drag force, Effects of intake temperature and injection pressure on auto-ignition is experimently analysed and discussed in detail.

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