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COUPLED SIMULATION OF COMMON RAIL FUEL INJECTION AND COMBUSTION IN A HSDI DIESEL ENGINE
Sukyoung Lee(이석영) 한국마린엔지니어링학회 2009 한국마린엔지니어링학회 학술대회 논문집 Vol.2009 No.-
In this study, the coupled simulation of fuel injection model and three-dimensional KIVA-3V code was tried to develop of the algorism for predicting the effects of varying fuel injection parameter on the characteristic analysis of fuel injection and emissions. The numerical analysis was done by STAR-CD code in order to calculate the intake air flow, and the combustion characteristics is examined by KIV A-3V code including the conditional moment closure (CMC) model to predict turbulent mean reaction rate. Parametric investigation with respect to twelve relevant injection parameters shows that there is a significant advantage in varying control chamber orifice diameter, needle valve spring constant and nozzle chamber orifice diameter with respect to minimizing the NOx and soot emissions. Consequently, in order to design the fuel injection system for reducing the specific emissions, it seems reasonable to suppose to be optimized the fuel injection system.
FIRE cede를 사용한 성층급기 연소현상에 관한 연구
이석영(Sukyoung Lee),허강열(Kang Y. Huh) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The direct-injection stratified-charge(D1SC) engine is considered to be a promising alternative to conventional spark ignition engines. It has, however, an unfavorable feature of high unburned hydrocarbon emission levels, especially during light load operations. The researches about constant volume combustion chamber(CVCC) mostly have been the experiments by visualization or the simpler numerical analysis until now. So it is needed the analysis of fluid and combustion characteristics in chamber by detail simulation. In this paper, this analysis is approaching basically the stratified charge combustion phenomena with 3 types of rich, homogeneous and lean mixture injection through the experiment and numerical analysis. And the combustion phenomena in chamber is numerically analyzed by the commercial code FIRE. The calculated results show the combustion phenomena which are mean temperature, OH radical and reaction rate, etc. in chamber.
이석영(Sukyoung Lee),정구섭(Kuseob Jeong),김규보(Kyubo Kim),전충환(ChungHwan Jeon),장영준(Youngjun Chang) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
In this experimental research, the characteristics of the transient mode in SI engine were studied to compare with pure gasoline and the fuels of RM50 (reformulated fuel) for performance and exhaust emissions without reconstruction of engine systems. RM50 has a wider range of combustion limitation, which is one of the methanol's characteristics. This causes a stable state of RM50 in the condition of unstable state of 1500 rpm, 9.8 kgf-m load. RM50 has relatively a low cycle by cycle variation, which is used to determine the driving state. It is determined that fuel stability is better and cycleby cycle variation varies within 10%, therefore, driving characteristics is relatively good. In all conditions, RM50 have lower exhaust emissions of CO, HC, NOx than gasoline. As a whole, RM50 shows a lower NOx emission because of combustion temperature and chemical reaction dynamics. RM50 has less incomplete combustion and it can be observed by the result of CO emission characteristics. RM50 shows 2~3㏈ less noise characteristics than gasoline however, RM50's noise characteristics is 0.5~2㏈ higher at part load condition. This is caused by a faster combustion speed of RM50 at part load, resulting an abrupt increase in pressure. This reason can be supposed accoding to the driving condition that to be noise is altered. Results of the experiments of rubber fusion and metal corrosion are very similler relatively and it increase the utility possibility of RM50.
고압 분사식 연료분사계 수치해석에 의한 디젤엔진 배기 예측
이석영(Sukyoung Lee),한인석(Insuk Han),허강열(Kang Y. Huh) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Numerical simulation has been carried out to investigate the effect on combustion and emissions in a common rail injection system. The relevant injection parameters are accumulator volume, control chamber initial volume, control orifice diameter, needle valve diameter and nozzle chamber initial volume, etc. Spray and combustion characteristics are examined by KIVA-3V with the conditional moment closure (CMC) model to predict the turbulent mean reaction rate. Conditional flame structures are estimated by the CMC model to determine mean state variables, instead of mean reaction rates. The main focus of this research is on optimization of a common rail injection system with respect to the various injection parameters under investigation.
메탄올 개질 연료를 사용한 SI엔진의 연료특성에 관한 수치해석
이석영(Sukyoung Lee),김규보(Kyubo Kim),정구섭(Kuseob Jeong),전충환(Chunghwan Jeon),장영준(Youngjun Chang) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.5_1
This research is to estimate the possibility of using RM50 without any modification of engine. Comparing the pressure and exhaust emission noise which are the result of the experiment with the result of the numerical analysis, it tended to be similar, and the analysis of combustion and noise characteristics of RM50 are as follows. Maximum heat release rate is proportional to combustion speed and as the combustion speed gets higher, the timing bring the maximum gets faster. As engine speed increases, the difference in turbulent burning speed for each fuel increases in low-load condition, On the contrary, in the high-load condition of 9.2㎏f-m, the fuel characteristics appear scarcely compared to low-load condition. Moreover, in the low speed, high-load condition of 1500rpm, 9.2㎏f-m which is unstable operation condition, the turbulent burning speed has lowest value, especially, that of gasoline reduced more than RM50. Turbulent intensity tends to increase as engine speed and load increase, and the fuel characteristics appears well in low-load condition. Therefore, it results in the increment of NO emission, but because of the influence of chemical reaction dynamics and lower flame temperature respectively, it produces less NO. Consequently, it is taken to consider combustion characteristics which include the combustion speed as well as the temperature in cylinder by low heating value to estimate NO emission by RM50. RM50 has higher CPL than gasoline. This is related to the combustion speed and as the speed gets faster, pressure increase rate increases and rapid combustion sound is brought out.
이석영(Sukyoung Lee),허강열(Kang Y. Huh) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This study describes the combustion characteristics of homogeneous charge of methane-air mixture with various initial pressure, equivalence ratio and ignition times of mixture in constant volume combustion chamber. The constant volume combustion chamber(CVCC) mostly has been studied by the experiments of visualization until now. So it is needed the numerical analysis of fluid and combustion characteristics in chamber by the more detail simulation. In this paper, the numerical analysis is tried to approach basically the homogeneous charge combustion phenomena under the various conditions, and the combustion phenomena in chamber is numerically analyzed by the commercial FIRE code. As a results, the combustion phenomena which were mean temperature, OH radical and reaction rate in chamber were investigated.
[디젤엔진부문] 단일영역 열발생량 계산법을 사용한 소형 HSDI와 IDI엔진의 연소특성 비교에 관한 연구
이석영(Sukyoung Lee),김규보(Kyubo Kim),최승환(Seanghwan Choi),전광민(Kwangmin Chun),전충환(Chunghwan Jeon),장영준(Youngjune Chang) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.11_1
Heat release analysis is a very important method in understanding the combustion phenomena inside an engine cylinder. In this study, one-zone heat release analysis was used with the measured cylinder pressures of a HSDI(high speed direct injection) and IDI(indirect injection) diesel engine. It has benefits of simple equation, fast speed, reliability. The object of the study is to compare the combustion characteristics between a HSDI and an IDI. Result of analysis, the maximum heat release rate of a HSDI is higher than an IDI because of long ignition delay period. The heat release curve of a IDI is more linear than an HSDI, so the combustion characteristics of a IDI is similiar to that of an SI engine. The combustion efficiency of a HSDI is higher than that of an IDI because of the smaller heat transfer loss of an HSDI.