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이상욱(Sanguk Lee),김재현(Jaehyun Kim),이점훈(Jeom-hunLee),신천식(Cheon Sig Sin) 제어로봇시스템학회 2012 제어로봇시스템학회 합동학술대회 논문집 Vol.2012 No.7
한국전자통신연구원(ETRI)에서는 방송통신위원회의 “다원화 항법주파수 감시 및 이용기술 개발” 과제를 2011년 부터 수행하고 있다. 이의 일환으로 항법주파수 감시를 위한 위성항법주파수(GPS) 혼신원 감시시스템을 개발하고 있으며, GPS L1, L2 신호에 대하여 혼신신호를 검출하고, 혼신원의 위치를 파악하는 기능을 수행한다. 한국전자통신연구원에서는 2011년 북한의 GPS 전파교란에 대한 대응으로 GPS 혼신원 감시시제품을 전방에 설치하였으며, 2012년 4월에 있은 북한의 GPS 전파교란에서 교란신호를 정상적으로 검출하였다. 본 논문에서는 2011년과 2012년에 있은 북한의 GPS 전파교란 경향을 분석하여 북한의 전파교란 변화방향에 대하여 살펴보고, GPS 전파교란에 대한 대응으로 설치한 혼신원 감시시제품의 설치 및 운용 상황을 살펴본다.
LPG 희박성층연소의 분위기 압력에 따른 분무 형상과 배기
이상욱 ( Sanguk Lee ),박상재 ( Sangjae Park ),배충식 ( Choongsik Bae ) 한국액체미립화학회 2018 한국액체미립화학회 학술강연회 논문집 Vol.2018 No.-
This research adopted the lean stratified combustion mode, which has a high potential for low fuel consumption. Although lean stratified combustion can catch the high fuel economy, the emission problem can still occur especially on Particulate Matter (PM) emission. The high PM emission is usually generated when the flame propagates through the rich fuel and air mixture. To decrease the area of rich fuel and air mixture within same mixing duration, liquefied petroleum gas (LPG) was applied because of its high vapor pressure. Despite faster fuel evaporation, it indicated high PM emission due to the high in-cylinder pressure. In this research, throttle valve operation was investigated to decrease the in-cylinder pressure. The engine experiment was conducted in a single cylinder research engine with the volume of 500cc. Outwardly opening piezo injector was centrally located. The engine experiment results indicate that filter smoke number (FSN) was decreased as the restriction of intake air was decreased. However, FSN shows an increasing trend as the restriction of intake air was decreased more than formal cases. To investigate this changing trend in sudden air restriction amount, spray-visualization was performed in a constant volume combustion chamber (CVCC). Mie-scattering and shadow photography were applied to detect both liquid and vapor phase of fuel spray formation simultaneously. As the restriction of air amount was decreased similar with the case of wide open throttle (WOT), the in-cylinder pressure was dramatically increased. The spray visualization results show that injected fuel spray was contracted towards its centerline of injector due to the high momentum exchange between the fuel and air. Consequently, PM emission can be generated not only the global equivalence ratio but also the formation of spray.