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레이저 굴절법을 이용한 LPG와 가솔린 연료의 화염전파 특성에 관한 연구
이기형,이창식,강건용,강우,Lee, Kihyung,Lee, Changsik,Kang, Kernyong,Kang, Woo 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.12
For the purpose of obtaining fundamental data which is needed to develope combustion system of LPG engine, we made constant volume chamber and analyzed flame propagation characteristics under different intial temperature, initial pressure and equivalence ratio which affect combustion of LPG. We investigated flame propagation speed of each fuel using laser deflection method and compared with the investigated flame propagation speed of each fuel using laser deflection method and compared with the results of image processing of flame. As a result, the maximum flame propagation speed was found at equivalence ratio 1.0 and 1.1 for LPG and gasoline, respectively. In the lean region, we can see that flame propagation speed of LPG surpasses that of gasoline. On the contrary, flame propagation speed of gasoline surpasses LPG in the rich region. As initial temperature and initial pressure were higher, flame propagation speed was faster. And, as equivalence ratio was larger and initial temperature was higher, combustion duration was shorter and maximum combustion pressure was higher.
이기형(KiHyung Lee),반재훈(ChaeHoon Ban),김동현(DongHyun Kim),홍봉희(BongHee Hong) 한국정보과학회 2004 한국정보과학회 학술발표논문집 Vol.31 No.2Ⅱ
최근 유비쿼터스 환경에서 객체에 태그를 장착하여 위치를 추적하는 응용분야가 늘어가고 있는 추세이며, 이러한 응용에서 빈번히 사용되는 질의는 객체의 위치를 찾는 find와 특정 위치의 객체를 찾는 look 질의가 있다. 이 두 질의에서 처리되는 데이터는 시간과 공간을 포함한 다차원 대용량 데이터이며 과거 및 현재 상태의 검색을 지원해야 하므로 효율적인 질의 처리를 위해서는 태그 객체를 위한 새로운 데이터 모델과 색인이 필요하다. 본 논문에서는 태그 객체를 간격 데이터로 정의하고 과거 및 현재 데이터에서 find와 look 질의를 처리할 수 있는 색인 구조를 제안한다. 제안하는 색인에서 노드에 오버플로우가 발생할 경우 새로운 단말 노드 분할 정책을 사용하여 분할하며 성능 평가를 통해서 기존 정책보다 우수함을 증명한다.
이기형(Kihyung Lee),김용래(Yonglae Kim),배재일(Jaeil Bae) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Recently, the international regulations about the exhaust emission of the motorcycle have been strengthened. In case of the motorcycle engines, the quantity of the exhaust emission is larger than that of the car because of the carburetor type fuel supply system, which can not control the A/F precisely. Therefore, the electrically controlled fuel injection type motorcycle has been emphasized to meet with this regulation. However, since the pulsation phenomenon happens in the intake port of the motorcycle because of the characteristic of high speed and the smaller layout than the passenger car driving condition, there are many difficulties to select the factor about control parameters needed to develop the ECU system. For addition, an air flow rate is the important basis parameter at the ECU system. In this paper, the pulsation values measured from the engine test were compared with the calculated value by WAVE, and we analyzed the intake pressure characteristic according to the driving condition. Finally, an air flow rate is estimated by simulation method.