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누설특성을 고려한 GDI 엔진용 연료펌프의 고압생성 증진에 관한 연구
나병철,김병수,최석우,Na, Byung-Chul,Kim, Byoung-Soo,Choi, Suk-Woo 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.6
GDI (Gasoline Direct Injection) engines are considered as one of the candidates for next generation engines of passenger cars, which reduce exhaust emissions and fuel consumption. In GOI engines, a high-pressure gasoline supply system is required to directly inject the fuel to combustion chambers. Because of low lubricity of gasoline fuel, the clearance between a plunger and a barrel in GDI fuel pumps is too wide to achieve smooth hydrodynamic lubrication. Thus, it is difficult to generate high-pressure condition in GDI fuel pump since large amount of leakage flow occurs between the plunger and the barrel In this study, an optimum plunger design is presented to minimize leakage in the aspect of flow control. This paper analyzes leakage flow characteristics in the clearance to improve pumping performance of GDI fuel pumps. Effects of groove in the plunger are studied according to variations of depth and width. Evaluations of pumping performance are determined by the amount of pressure drop in the leakage path assuming a constant leakage flows. Both of turbulence and incompressible models are introduced in CFD (Computational Fluid Dynamics) analysis. Design parameters have been introduced to minimize leakage in limited space, and a methodological study on geometrical optimization has been conducted. As results of CFD analysis in various geometrical cases, optimum groove depths have been found to generate maximum sealing effects on gasoline fuel between the plunger and the barrel. This procedure offers a methodological way of an enhancement of plunger design for high-pressure GDI fuel pumps.
최석우 가톨릭대학교 사목연구소 2000 司牧硏究 Vol.8 No.-
지난 50년 동안을, 나는 보좌신부로 시작하여 소신학교 교사, 해외유학, 대신학교 교수, 본당신부, 연구소 전담 등 꽤 다양하게 보냈다. 이에 관한 이야기를 구체적으로 시작하기 전에 편의상 이 50년을 시기로 구분해 본다면, 처음 보좌와 유학 등으로 보냔 12년은 사제로서의 기반을 좀 더 확고히 한 계기로 볼수 있다면, 다음 13년을 그것을 바탕으로 하여 본격적인 학문 활동과 사목활동을 전개한 시기로 , 마지막 25년은 오로지 교회사 연구에 몰두한 시기로 볼 수 있겠다. 첫째시기에 관한 이야기는 지면 관계로 생략하기로 하고, 둘째와 셋째시기에 관해서 중점적으로 이야기를 하고자 한다.
박종우,최석우,송만수 충남대학교 의과대학 지역사회의학연구소 1994 충남의대잡지 Vol.21 No.2
Nine trials of general chemistry and eight trials of blood gas were performed for external quality assessment of clinical chemistry using commercial control sera in 1994 in Korea. Test items of general chemistry were sodium, potassium, chloride, BUN, glucose, calcium, phosphorus, uric acid, creatinine, bilirubin, total protein, albumin, cholesterol, triglycerides, AST, ALT, and LDH. Test items of blood gas were pH, pO_2 and pCO_2. The mean of each item in general chemistry and in blood gas were used as designated target value for the calculation of Variance index score(VIS), respectively. Variance index score(VIS) system are used to evaluate the performance of participant's quality control. Also coefficient of variation(CV) was given as guidance of each method. Mean CV of 14 items except enzyme tests was 7.0% and the range was 2.4-12.7%. T he CV's of glucose, phosphorus, uric acid, creatinine, bilirubin, total protein, albumin, and cholesterol are better than last year. Mean VIS of 16 items in general chemistry was 57 and the performance of 11 items was improved than mean. In blood gas control, the range of mean CV was 0.2% in pH, 11% in pO_2, and 7.0% in pCO_2. The range of mean CV of blood gas in each trial was 0.1-0.3% in pH, 8.8-14.5%- in pO_2 and 5.1-16.9% in pCO_2.