http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
LPG 액상분사식 인젝터에서 후적에 의한 아이싱 특성 연구
박철웅,김창업,최교남,강건용,Park, Cheol-Woong,Kim, Chang-Up,Choi, Kyo-Nam,Kang, Kern-Yong 한국자동차공학회 2007 한국 자동차공학회논문집 Vol.15 No.5
Since the liquid phase LPG injection(LPLI) system has an advantage of higher power and lower emission characteristics than the mixer type fuel supply system, many studies and applications have been conducted. However, the heat extraction, due to the evaporation of liquid fuel, causes not only a dropping of LPG fuel but also icing phenomenon that is a frost of moisture in the air around the nozzle tip. Because both lead to a difficulty in the control of accurate air fuel ratio, it can result in poor engine performance and a large amount of HC emissions. The experimental investigation was carried out on the bench test rig in this study. It was found that n-butane, that has a relatively high boiling point($-0.5^{\circ}C$), was a main species of droplet composition and also found that the droplet problem was improved by the use of a large inner to outer bore ratio nozzle whose surface roughness is smooth. The icing phenomena were decreased when the an engine head temperature was increased, although a large amount of icing deposit was still observed in the case of $87^{\circ}C$. Also, it was observed that the icing phenomenon is improved by using anti-icing bushing.
디젤 엔진에서 금속 푬을 적용한 SCR 촉매의 특성 분석
김용래 ( Yong Rae Kim ),최교남 ( Kyo Nam Choi ) 한국분무공학회 2013 한국액체미립화학회지 Vol.18 No.4
SCR(Selective Catalytic Reduction) is a major after-treatment solution to reduce NOx emission in recent diesel engines. In this study, a metal foam is applied as an alternative SCR substrate and tested in a commercial diesel engine to compared with a conventional ceramic SCR system. Basic engine test from NO-13 mode shows that a metal foam catalyst has lower NOx conversion efficiency than a ceramic catalyst especially over 350ae. A metal foam catalyst has characteristics of high exhaust gas pressure before a SCR catalyst and high heat transfer rate due to its material and structure. NOx conversion effi-ciency of a metal foam catalyst shows an increasing tendency along with the increase of exhaust gas temperature by 500ae. The effect of urea injection quantity variation is also remarkable only at high exhaust gas temperature.
김창업 ( Chang Up Kim ),최교남 ( Kyo Nam Choi ),강건용 ( Kern Yong Kang ),박철웅 ( Cheol Woong Park ) 한국분무공학회 2011 한국액체미립화학회지 Vol.16 No.1
In recent years, the need for more fuel-efficient and lower-emission vehicles has driven the technical development of alternative fuels such as LPG (Liquefied Petroleum Gas) which is able to meet the limits of better emission levels without many modifications to current engine design. LPG has a high vapor pressure and lower viscosity and surface tension than diesel and gasoline fuels. These different fuel characteristics make it difficult to directly apply the conventional gasoline or diesel fuel pump. Self acting lubricated groove design or coating can be used in high-speed and high precision spindle system like a roller-vane type fuel pump, because of its advantages such as low frictional loss, low heat generation, averaging effect leading better running accuracy and simplicity in manufacturing. Those design method can also affect the atomization of fuel from the injector and the formation of fuel film on the intake manifold. In this study, experiments are carried out to get performance characteristics of initial and steady state operation. The characteristics of vane type fuel pump were investigated to access the applicability on LPLi engine.
오봉근(Bong-keun Oh),최교남(Kyo-nam Choi),최형철(Hyung-cheol Choi),임기조(Kee-joe Lim) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
Our company(KOWACO) has periodically performed off-line diagnostic test for 14 hydro generators (rated 11 ㎸ over) for 15 years. In this paper, we summarized results of dissipation factor tip-up test and partial discharge test about these generators. Among these, we chose two generators and performed insulation reinforcement (cleaning and varnish painting). We compared change of insulation condition for the stator winding based upon off-line diagnostic test result before and after repair. Test result shows that insulation condition was improved after insulation reinforcement. This insulation reinforcement has a function to reduce cause of deterioration, so we can know that it extends lifetime of generator and it is a very important factor for stable operation of facilities.
오봉근(Bong-keun Oh),최교남(Kyo-nam Choi),한창동(Chang-dong Han),임기조(Kee-joe Lim) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
Stator winding of hydro generator is gradually deteriorated by multi-stress and steady degradation of insulation results in insulation breakdown. The region where insulation breakdown occurs in stator winding is part where the multi-stress causes the defect of insulation material and electrical stress has been concentrated. Therefore, we judged locations of insulation breakdown to be varied according to various stress factors in service. In this paper, we drew the stator winding of hydro generators which has run for a long time and separated it into 3 parts (central part, end winding part, drawing part) according to the positions laid on the core. We performed electrical and thermal stress on these specimens for 1000 hrs under the same condition, measured the condition regularlyand analyzed the insulation status of each winding by performing partial discharge test. In addition, we analyzed the trend of partial discharge concerning specimens that caused the insulation breakdown during aging.
오봉근(Bong-Keun Oh),최교남(Kyo-Nam Choi),최형철(Hyung-Cheol Choi),임기조(Kee-Joe Lim) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.5
Our company(KOWACO) has periodically performed off-line diagnostic test for 14 hydro generators (rated 11 kV over) for 15 years. In this paper, we summarized results of dissipation factor tip-up test and partial discharge test about these generators. Among these, we chose two generators and performed insulation reinforcement (cleaning and varnish painting). We compared change of insulation condition for the stator winding based upon off-line diagnostic test result before and after repair. Test result shows that insulation condition was improved after insulation reinforcement. This insulation reinforcement has a function to reduce cause of deterioration, so we can know that it extends lifetime of generator and it is a very important factor for stable operation of facilities.
김태권(Tae kwon Kim),장준영(Jun Young Jang),유영돈(Young Don Yoo),최교남(Kyo Nam Choi) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper presents the applicability of low caloric synthetic gas from coal gasification to a gas engine system. A commercial LPG engine is modified to use the low caloric synthetic gas from coal gasification as the gas engine fuel. The modification is focused on the fuel supplying system, which includes air flowrate adjusting orifice, gas mixer, vaporizer, preheater, regulators, and fuel tank. The electrical system and others for the alternative fuel are also redesigned and replaced. From the results of engine performance data, we have demonstrated that the engine modified by using coal gasification gas is well operated from idle to wide open throttle conditions although the engine power is somewhat reduced relative to LPG fueled engine. This paper addresses the need to determine the practical potential for such a concept and to identify further research and development efforts that may be necessary.