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커먼레일 디젤엔진의 인젝터 클리닝이 배기가스에 미치는 영향에 관한 연구
조홍현(Cho, Hong-Hyun),김태중(Kim, Tae-Jung) 한국산학기술학회 2014 한국산학기술학회논문지 Vol.15 No.10
디젤엔진의 사용은 루돌프 디젤에 의하여 발명된 이후 산업의 발달을 이끌어가는 중추적인 역할을 하고 있다. 2013년 기준으로 국내의 디젤엔진의 차량은 7,395,739대이다. 디젤엔진에서의 인젝터는 엔진의 구동에 직접적인 역활을 수행하기 때문에 성능향상에 대한 연구는 지속적으로 이루어지고 있다. 본 연구는 운행 중인 디젤차량의 매연의 농도와 인젝터 클리닝 전·후의 관계를 비교분석하기 위하여 인젝터 클리닝 전·후의 매연의 농도를 KD147 모드(“운행차 수시점검 및 정기검사의 배출허용기준”)로 측정하여 인젝터 클리닝이 매연 저감에 미치는 영향에 대하여 실험적으로 고찰하였다. 실험결과 인젝터 클리닝 후의 매연의 농도가 20% 이상 감소하는 것을 확인하였으며 매연의 농도의 감소율은 매연의 발생량이 클수록 증가하 는 것으로 나타났다. As a response to exhaust gas regulations, the electronic control system was applied to the diesel engine. The injected fuel mass and injection timing are accurately controlled using it, and the fuel efficiency and the engine output are significantly increased. In addition, the noise and the vibration of vehicles are decreased. To maintain the optimal performance of an electronic control diesel engine, it is important to control the fuel injection pressure accurately using the fuel pressure regulator. When the fuel pressure regulator is not worked normally, the failure phenomena (starting failure, staring delay, accelerated failure, engine mismatch et al.) occurred because the fuel pressure is not stabilized and controlled accurately. In this study, the effects on a fuel pressure, return fuel mass flow, and engine rotating speed according to the control rate of fuel pressure regulator were investigated to analyze the performance variation under the failure conditions of a fuel pressure regulator. As a result, when the control rate of a fuel pressure regulator decreased by 4%∼6% compared to that of the standard condition, the variation of engine rotating speed and return fuel flow were increased greatly, and the abnormal condition occurred. In addition, it is possible to diagnose the failure of a fuel pressure regulator by monitoring these conditions.
만성 알코올 급여 흰쥐에서 보리 추출물 섭취가 Cytochrome P450 효소 조절 및 항산화계에 미치는 영향
이유현(Yoo-Hyun Lee),이정민(Jeongmin Lee),임은정(Eun-Jeong Im),전우진(Woojin Jun),조홍연(Hong Yon Cho) 한국식품영양과학회 2009 한국식품영양과학회지 Vol.38 No.10
본 연구에서는 보리 추출물을 이용하여 알코올 유도 P450 계열 효소 활성을 조절함으로써 라디칼 및 중간체의 발생감소와 항산화 효소의 활성증강에 의한 보호효과를 연구하였다. ICR mice를 대상으로 대조군(Control), 알코올군(EtOH), 알코올-보리 추출물 급여군(EtOH-B)으로 나누어 전체 열량의 35%에 해당하도록 조성된 알코올 액체 식이를 알코올군 및 알코올-보리 추출물 급여군에 28일 간 공급하였다. 알코올 투여군은 P450 함량에 있어서 대조군에 비하여 급격한 증가를 보였으며, 알코올-보리추출물 급여군은 대조군 수준으로 유의적인 감소를 하였다. 알코올 유도 CYP2E1, CYP1A2는 알코올군에서는 유의적인 증가를 보였으며, 알코올-보리 추출물 투여군에서 이들 효소의 활성을 유의적으로 억제시키는 결과를 확인할 수 있었다. 생체 내 방어시스템의 변화 면에서 알코올 급여군에서 급격하게 감소한 catalase 활성이 보리 추출물 급여군에서는 유의적으로 증가하여, CYP2E1의 활성억제에 의한 라디칼 발생 저하를 확인할 수 있었다. 이상의 실험 결과로서, 보리 추출물은 알코올 유도 CYP2E1, CYP1A2 효소 활성의 억제와 생체 내 방어 기작의 효과적인 활성화에 의하여 알코올성 간 손상의 개선 소재로 활용가능 할 것이라고 사료된다. The effects of methanol extract of barely (Hordeum vulgare) on alcohol-induced damages of liver were investigated in male ICR mice. Mice were divided into three groups, control, ethanol, and ethanol plus 0.15% of barley extract. After four weeks of ethanol feeding, ethanol group significantly increased the P450 content, CYP2E1 and CYP1A2 enzyme activities, whereas ethanol plus barely group markedly decreased to levels similar to control group. Catalase activity in ethanol group was significantly lower than that in control group; however, ethanol plus barely group stimulated catalase activity as well as SOD activity significantly. These results indicated that barely extract modulated P450 enzymes for ethanol-induced liver damage and might be useful in developing functional food for alcoholic liver damage.
다양한 운전조건에서 이젝터를 적용한 CO<sub>2</sub> 냉동기의 성능비교
강변,조홍현,Kang, Byun,Cho, Hong-Hyun 대한설비공학회 2011 설비공학 논문집 Vol.23 No.7
Recently, many researchers have analyzed the performance of the transcritical $CO_2$ refrigeration cycle in order to identify opportunities to improve the system energy efficiency. The reduction of the expansion process losses is one of the key issues to improve the efficiency of the transcritical $CO_2$ refrigeration cycle. In this study, the analytical study on the performance characteristics of $CO_2$ cycle with an ejector carried out with a variation of outdoor temperature, gascooler inlet air velocity, evaporator inlet air velocity, and evaporator inlet air temperature. As a result, the system performance could be improved over 85% by using an ejector for various operating condition because of the reduction of compressor work. Moreover, the cooling capacity increased about 18% for variable outdoor condition. Therefore, the high performance of an ejector system could be maintained for wide operating conditions and system reliability could be improved compared to that of a basic system.
실내설정온도에 따른 태양열 하이브리드 열펌프 시스템 운전특성에 대한 실험적 연구
김원석(Kim Won-Seok),조홍현(Cho Hong-hyun) 한국태양에너지학회 2010 한국태양에너지학회 논문집 Vol.30 No.6
Experimental study on the operating characteristics of a solar hybrid heat pump system according to indoor setting temperature were carried out during spring and winter season. The system was consisted of a concentric evacuated tube solar collector, heat medium tank, heat storage tank, and heat pump. As a result, the heating load was increased by 21.1% when the indoor setting temperature rose by 2℃ for the same ambient temperature. Besides, the spring season had good outdoor conditions compared to the winter season, therefore the heating load was reduced and heat gain by collector increased, relatively. In case of the winter season, the solar fraction was shown less than 10% because the heat losses of system and space increased considerably. The solar fraction decreased significantly as the indoor setting temperature increased.
Rhodopseudomonas palustris KK14 를 이용한 소규모 돈분폐수처리공정의 최적화
김한수(Han Soo Kim),오준현(Chun Hyun Oh),김혁일(Hyuk Il Kim),조홍연(Hong Yon Cho),양한철(Han Chul Yang) 한국응용생명화학회 1994 Applied Biological Chemistry (Appl Biol Chem) Vol.37 No.4
To develop the treatment process of swine wastewater using Rhodopseudomonas palustris KK14 with high utilizable ability of organic acids, some operating conditions were investigated and optimized in flask-scale and laboratory-scale reactors. The optimal operating conditions in photosynthetic bacteria (PSB) reactor of semi-continuous type were obtained at HRT 6 day, 5% (v/v/day) seeding rate of PSB sludge and 10% (v/v/day) returning rate of PSB return sludge. Under the above operating condition, COD level of the wastewater (initial COD: 10 g/ℓ) was reduced to about 1-7 g/ℓ after 4 days treatment and MLSS was held constant at 4∼5 g per liter. In laboratory-scale process consisted of 5.2ℓ anaearobic digestion reactor and 15ℓ PSB reactor, the total removal rates of COD and BOD were increased to 95% and 96% by the continuous operation for 5.36 days, respectively, showing 3 Kg COD/㎥/day COD loading rate and 1.1 Kg COLA/Kg MLSS/day sludge loading rake in PSB reactor. The offensive odor was considerably removed through the treatment process of swine wastewater.