• Title/Summary/Keyword: Combustion engine

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Investigation of Combustion Strategy for Commercialization of Low Temperature Diesel Combustion Engine (저온연소엔진 실용화를 위한 연소전략에 대한 연구)

  • Shim, Euijoon;Han, Youngdeok;Shin, Seunghyup;Kim, Duksang;Kwon, Sangil
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.6
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    • pp.120-127
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    • 2014
  • Robustness and controllability are the key factors in internal combustion engine commercialization. This study focuses on the combustion strategy to commercialize the low temperature diesel combustion technology. Various LTC combustion methods such as PPCI, MK and highly diluted mixing controlled LTC were conducted on 6.0L heavy duty diesel engine. To find the best feasible LTC strategy, emission level, fuel consumption and combustion safety during the combustion mode change were considered. Experiments were carried out under various engine operating conditions; engine speed & load, EGR level, injection timing. Finally, this study suggests realizable LTC combustion strategy; moderate EGR level and slight early injection are possible to considerably lower PM, NOx emission and expand LTC operating range up to 50% load without CO and HC emission.

A Study on the Ultra Lean Combustion Characteristics of the BMW N53 GDI Engine (BMW N53 직접분사식 가솔린 엔진의 초희박 연소특성에 관한 연구)

  • Kim, Hong-Suk;Oh, Jin-Woo;Kim, Sung-Dea;Park, Chul-Wong;Lee, Seok-Whan;Jeong, Young-Il
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.6
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    • pp.82-89
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    • 2011
  • Ultra lean combustion with stratified air-fuel mixture is one of the methods that can improve fuel economy of gasoline engines. The aim of this study is to show that how much fuel economy is improved and what are differences in engine control of the ultra lean combustion compared with stoichiometric combustion. In this study, the BMW N53 GDI engine, which is one of ultra lean combustion GDI engines introduced in the market recently, was tested at various engine operating conditions. Results indicated that fuel consumption rates were improved by 11.9~25.8% by the ultra lean combustion compared with stoichiometric combustion. It was also found that multiple fuel injection, multiple spark, early intake valve opening, and large vlave overlap duration were the features of the ultra lean combustion for combustion stability and emission improvement.

COMBUSTION AND EMISSION CHARACTERISTICS OF A TURBOCHARGED DIESEL ENGINE FUELLED WITH DIMETHYL ETHER

  • Wu, J.;Huang, Z.;Qiao, X.;Lu, J.;Zhang, L.;Zhang, J.
    • International Journal of Automotive Technology
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    • v.7 no.6
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    • pp.645-652
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    • 2006
  • This paper is concerned with an experimental study of a turbocharged diesel engine operating on dimethyl ether(DME). The combustion and emission characteristics of DME engine were investigated. The results showed that the maximum torque and power with DME could achieve a greater level compared to diesel operation, particularly at low speeds; the brake specific fuel consumption with DME was lower than the diesel at low and middle engine speeds. The injection delay of DME was longer than that of diesel. However, the maximum cylinder pressure, maximum pressure rise rate and combustion noises of DME engine were lower than those of diesel. The combustion velocity of DME was faster than that of diesel, resulting in a shorter combustion duration of DME. Compared with the diesel engine, $NO_x$ emissions of the DME engine were reduced by 41.6% on ESC data. The DME engine was smoke free at all operating points of the engine.

Combustion Characteristics in the Offset Bowl Combustion Chamber Diesel Engine (편심된 보울의 연소실을 갖는 디젤 엔진의 연소 특성 해석)

  • 김홍석;성낙원
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.7
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    • pp.54-65
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    • 1999
  • In this study, the flow field, spray structure, and combustion process were investigated in a direct injection diesel engine having an offset bowl in a combustion chamber. The KIVA-3V code was used in this study. In order to obtain accurate results, a droplet atomization model, wall impingement model, and ignition delay concept were added to KIVA-3V code. The results showed that the offset bowl engine had a large vortex flow. The direction of this flow counteracted to the direction of fuel injection in one side of combustion chamber. It decreased local turbulent kinetic energy and eventually nonuniform combustion was resulted in an offset bowl engine. In comparison with a center bowl engine case, the peak cylinder pressure was decreased about 6%. Finally , the effect of swirl on combustion was investigated in an offset bowl engine . As the became stronger, the nouniform characteristics in combustion were increased.

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A Study on the Reduction of NO Emission from a Diesel Engine with 2-Stage Type Combustion Chamber (2단 연소형 연소실을 갖는 디젤기관의 NO 저감에 관한 연구)

  • 진선호;배종욱
    • Journal of Advanced Marine Engineering and Technology
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    • v.26 no.5
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    • pp.554-564
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    • 2002
  • A newly designed combustion chamber of diesel engine with a modified piston crown was prepared for the purpose of investigation for reduction of NO emission. It was intended to realize 2-stage combustion that is to keep fuel rich condition during early stage of combustion and fuel lean condition during next stage. The engine was tested on various conditions concerning exhaust gas emissions especially about NO emission and simultaneously fuel consumption rate. It was found that the engine with 2-stage combustion type piston emits significantly low NO at various speed and torque compared with conventional engines, but it raised points at issue in CO and smoke emissions with fuel consumption rate. The increasing of injection pressure on 2 stage combustion type diesel engine affects on CO and smoke emission considerably to reduce but slightly on NO to increase. The effect of 2-stage combustion was better at low speed than at high speed.

The Research about Engine Speed change Effect on HCCI Engine Combustion by Numerical Analysis (엔진회전속도의 변화가 HCCI엔진연소에 미치는 영향에 관한 수치해석 연구)

  • Lim, Ock-Taeck
    • Journal of ILASS-Korea
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    • v.16 no.3
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    • pp.126-133
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    • 2011
  • In HCCI Engine, combustion is affected by change of compression speed corresponding to engine speed. The purpose of this study is to investigate the mechanism of influence of engine speed on HCCI combustion characteristics by using numerical analysis. At first, the influence of engine speed was shown. And then, in order to clarify the mechanism of influence of engine speed, results of kinetics computations were analyzed to investigate the elementary reaction path for heat release at transient temperatures by using contribution matrix. In results, as engine speed increased, in-cylinder gas temperature and pressure at ignition start increased. And ignition start timing was retarded and combustion duration was lengthened on crank angle basis. On time basis, ignition start timing was advanced and combustion duration was shortened. High engine speed showed higher robustness to change of initial temperature than low engine speed. Because of its high robustness, selecting high engine speed was efficient for keeping stable operation in real engine which include variation of initial temperature by various factors. The variation of engine speed did not change the reaction path. But, as engine speed increased, the temperature that each elementary reaction would be active became high and reaction speed quicken. Rising the in-cylinder gas temperature of combustion start was caused by these gaps of temperature.

A study on the spray combustion characteristics in a cylinder of a D.I.diesel engine with the electronically controlled injector (전자제어식 직접분사 디젤 엔진 연소실내의 분무연소 특성에 관한 연구)

  • 정재우;김성중;이기형;선우명호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.2
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    • pp.50-56
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    • 2000
  • It is well known that the combustion phenomenon of diesel engine is an unsteady turbulent diffusion combustion. Therefore, the combustion performance of diesel engine is related to a complex phenomenon which involves the various factors of combustion, such as a injection pressure, injection timing, injection rate, and operation conditions of engine. In this study, the spray and the flame development processes in a single cylinder D.I. diesel visualization engine which uses the electronically controlled injection system were visualized to interpret the complicated combustion phenomenon by using high speed CCD camera. In addition, the cylinder pressure and heat release rate were also obtained in order to analyze the diesel combustion characteristics under several engine conditions.

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Flame and Combustion Characteristics of D.I. HCCI Diesel Engine using a Visualization Engine (가시화 엔진을 이용한 직분식 예혼합 압축착화 디젤엔진의 화염 및 연소특성)

  • 권오영;류재덕;이기형;이창식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.6
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    • pp.100-107
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    • 2002
  • Combustion characteristics of diesel engine depends on mixture formation process during Ignition delay and premixed flame region. Fuel and air mixture formation has a great influence on the exhaust emission. Therefore, the present study focused on the combustion mechanism of Homogeneous Charge Compression Ignition (HCCI) engine. This study was carried out to investigate the combustion characteristics of direct injection type HCCI engine using a visualization engine. To investigate the combustion characteristics, we measured cylinder pressure and calculated heat release rate. In addition, we investigated the flame development process by using visualization engine system. From the experimental result of HCCI engine, we observed that cool flame was always appeared in HCCI combustion and magnitude of cool flame was proportional to magnitude of hot flame. And we also found that fuel injection timing is more effective to increase lean homogeneous combustion performance than intake air temperature. Since increasing the intake air temperature improved fuel vaporization before the fuel atomizes, we concluded that increasing the temperature has disadvantage fur homogeneous premixed combustion.

A Numerical Study on Combustion Characteristics of HCCI Engine with Stratification Condition of EGR Exhaust Gases (EGR 배기가스의 성층화 조건에 따른 HCCI 엔진의 연소 특성에 관한 수치해석 연구)

  • Lee, Won-Jun;Lee, Seung-Ro;Lee, Chang-Eon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.6
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    • pp.46-52
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    • 2011
  • Homogeneous charge compression ignition (HCCI) is the best concept able to provide low NOx and PM in diesel engine emissions. This new alternative combustion process is mainly controlled by chemical kinetics in comparison with the conventional combustion in internal combustion engine. However, HCCI engine's operation have an excessive rate of pressure rising during the combustion process. In this study, stratification condition of EGR exhaust gases was used to reduce the pressure rising during the combustion process in HCCI engine. Also, combustion characteristics and emissions characteristics were investigated using the detailed diesel surrogate reaction mechanism.

Characteristics of Turbopump and Hydraulic lines of Staged Combustion Cycle Engine (다단연소사이클 엔진의 터보펌프 및 유공압 라인 특성)

  • Lee, Jungho;Jeon, Junsu;Hwang, Chang-Hwan;Woo, Seongphil;Lee, Kwangjin;Yoo, Byungil;Han, Yeoungmin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.94-98
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    • 2017
  • Research for developing 9 tonf-class staged combustion cycle engine which is high performance upper stage engine has been conducted. Technical demonstration model of the staged combustion cycle engine was installed in combustion test facility of Naro space center. Combustion tests of Power-pack which consists of pre-burner and turbopump without main combustion chamber and combustion tests of engine have been conducted. The vacuuming process of hydraulic lines is introduced and the characteristics of turbopump and hydraulic lines of engine combustion test are described in this paper.

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