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송정근(Song Jungkeun) 한국언어문학회 2010 한국언어문학 Vol.75 No.-
This paper which examined the history of the study on adjective in Korean aims to explain the change of the recognition of adjectival category. In this study, 4 stages are assumed to show the shift of establishing a adjectival category in terms of diachronic approaches. In first stage, It is known that there is no adjective in Korean or Korean adjective is very different from that of western Language by the foreigner during the early 20th century. It is the second stage that such a bias based on western oriented views is overcame by the Korean traditional grammarian who knows that Korean adjective is similar to verb rather than noun and had tried to explain the differences between adjective and verb in the middle of 20th century. The new suggestions that Korean adjective is unaccusative or all Korean adjectives are verbs has proposed in third stage in the influences of the new linguistic theories. The last stage is when the linguistic typologic approaches on the word classes are introduced to Korean linguistic society. By the typological study on adjective, it is turned out that Korean adjective are not the exceptional one even though it can be a predicate like verbs.(verb like adjective)
발전용 대형 디젤 엔진의 천연가스-디젤혼소 운전 특성에 대한 수치해석 연구
조정근(Jungkeun Cho),박상준(Sangjun Park),송순호(Soonho Song),허광범(Kwang-beom Hur) 한국가스학회 2015 한국가스학회지 Vol.19 No.2
본 연구는 발전용 디젤 엔진을 천연가스/디젤 혼소 엔진으로 개조하기 위한 선행 연구로 1.5MW급 발전용 디젤 엔진을 대상으로 상용 프로그램인 GT-Power를 이용해 수치해석을 진행하였다. 흡기 포트에 천연가스 분사 장치를 추가한 수치해석 모델을 통해 기존 엔진에서 천연가스와 디젤을 혼소시킬 경우 엔진 성능에 미치는 영향과 특성에 대해 분석하였다. 엔진 속도 720RPM, 혼소율 0%~40%까지 5개 조건에서 수치해석을 진행했다. 연구 결과 혼합 연소 시 천연가스의 비율이 증가할수록 출력이 감소하는 경향을 보였으며 혼소율 40%에서 출력이 18.4% 감소하였다. 이에 따라 실험계획법(Design of Experiment)을 통해 연료 분사시기와 연료 분사 기간에 대한 영향을 분석했다. 또한 이러한 영향을 고려해 연료 분사시기와 분사기간을 최적화시켜 혼소 엔진 출력과 디젤 엔진의 출력을 비교하여 혼소엔진으로의 개조에 따른 엔진의 출력과 효율에 대한 변화를 정량적으로 도출하였다. 그 결과 혼소율 40%에서 엔진 출력은 8.55% 감소하여 최적화 이전에 비해 12.5%의 개선 효과를 보였다. This study is an 1-D numerical study prior to modification of diesel engine for power plants to natural gas/diesel dual fuel engine using GT-Power with 1.5MW diesel engine for power generation. Natural gas injector was installed to intake manifold for dual fuel engine model. Effects on engine performance and characteristics were investigated when dual fuel is used in unmodified diesel engine. The analysis was done under 5 conditions from 0% to 40% of mixing rate on 720RPM engine speed. As a result of research, the engine performance was decreased as increasing ratio of natural gas. Engine brake power was decreased by 18.4% under 40% mixing rate condition. To clarify the reason, effects of injection timing and period were evaluated with DOE method. Considering this result, optimization was done for these parameters. Also, comparison between performances of dual fueled engine and diesel engine was made after optimizing the timing of injection by DOE method. As a result, engine brake power was decreased by 8.55% under mixing rate 40% condition showing 12.5% improvement.
Cho, Jungkeun,Park, Sangjun,Song, Soonho Elsevier 2019 ENERGY Vol.187 No.-
<P><B>Abstract</B></P> <P>The fundamental combustion characteristics and engine performance of a dual-fuel engine, fueled with diesel and natural gas, were investigated using a commercial 1D simulation program (GT-Power). Furthermore, the effects of air-fuel ratio under dual-fuel combustion conditions were studied, and optimized design points that minimize brake-specific fuel consumption (BSFC) and nitrogen oxides (NO<SUB>X</SUB>) emissions simultaneously were determined using a multi-objective Pareto optimization method. The engine model was validated based on experimental results and previous work under various engine loads. The thermal efficiency of the engine, which was modified from a diesel to a dual-fuel engine, showed a decreasing tendency as the natural gas substitution ratio (NSR) increased due to changes in the combustion characteristics. The decline in thermal efficiency in dual-fuel combustion could be improved somewhat by optimizing the injection strategy. Under dual-fuel combustion conditions, an optimum air-fuel ratio value for BSFC could be determined, especially for higher NSR conditions. However, NO<SUB>X</SUB> emissions showed a tendency to increase with increasing air-fuel ratio. The relationship between the trends was more than a simple tradeoff, so multi-objective Pareto optimization was conducted to minimize both BSFC and NO<SUB>X</SUB> emissions, with start of injection timing and air-fuel ratio as variables. Ultimately, optimal design points were determined.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The large stationary engine was modeled and modified to dual-fuel engine. </LI> <LI> The characteristics of dual-fuel combustion were investigated. </LI> <LI> The effect of air-fuel ratio under dual-fuel combustion condition are investigated. </LI> <LI> The optimal design points for improving fuel economy and NOx emission are suggested. </LI> <LI> Helpful methodology for conceptual design of virtual engine system was suggested. </LI> </UL> </P>
송재은(Jaeeun Song),이정근(Jungkeun Rhee) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
As many diesel engines are utilized in middle class or compact cars, the demands for quiet and good sound quality in diesel engine also increase more and more. High combustion pressure in idle and light load acceleration mode makes it difficult to make low noise like that of gasoline engine, but the sound quality can be enhanced by introducing DOE. For the complete improvement of diesel engine sound quality, it is necessary to consider the combustion and mechanical noise. But it is thought that the reduction of the combustion noise can show us a short way to get full improvement. The most important factor to be considered in this study is to find the optimum combustion conditions without any deterioration of emission level and drivability. This paper includes the DOE method as a tool to find out the optimized combustion conditions, which is possible to realized better sound quality in idle through that method without deteriorating the important two limited conditions.
Park, Sangjun,Cho, Jungkeun,Park, Jungsoo,Song, Soonho Pergamon Press 2017 Energy Vol.124 No.-
<P><B>Abstract</B></P> <P>The effect of methanol addition on the performance and NO<SUB>x</SUB> emission of a diesel engine was investigated using one-dimensional engine cycle simulation. The methanol component was injected into the intake manifold of a diesel engine at a certain energy fraction (0, 5, 10, or 15%) of the fuel. The in-cylinder pressure and temperature decreased as the methanol content increased due to the lower cetane number and lower heating value of methanol. The resulting decrease in the combustion efficiency lowered the NO<SUB>x</SUB> emission and brake thermal efficiency of the engine, and consequently deteriorated the brake specific fuel consumption (BSFC). The BSFC decreased but the NO<SUB>x</SUB> emission increased with advanced injection timing under dual-fuel operating conditions. Response surface plots of the BSFC and NO<SUB>x</SUB> emission as a function of the injection timing and exhaust gas recirculation (EGR) rate were obtained using a design of experiment method. The optimal Pareto fronts that improved both the BSFC and NO<SUB>x</SUB> emission were found. The EGR rate had a greater influence on the optimal Pareto front than the injection timing, which suggested that design parameters such as the injection timing and EGR rate could be used to control the performance and emission under various duel-fuel conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The performance and emission of a diesel-methanol dual-fuel engine is investigated. </LI> <LI> The BSFC of the diesel engine is deteriorated as the methanol content increased. </LI> <LI> The NOx emission of the diesel engine is reduced as the methanol content increased. </LI> <LI> Both the BSFC and NOx emission are improved by multi-objective Pareto optimization. </LI> <LI> Design parameters are suggested to control the performance of the dual-fuel engine. </LI> </UL> </P>