• 한국대기환경학회지
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• 제28권2호
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• pp.203-210
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• 2012

The purpose of this study is to evaluate the diesel retrofit program which have been proceeded for the last 7 years in Gyeonggi-do. Diesel retrofit programs in Gyeonggi-do consist of the attachment of DPF (Diesel Particulate Filter), p-DPF (partial-DPF) and DOC (Diesel Oxidation Catalyst), switching to LPG engine, scraping an old cars. Emission reduction by diesel retrofit program was estimated $N_2O$ 8,313.4 ton/year, PM10 3,626.4 ton/year, VOC 8,078.5 ton/year in 2010. The benefit-cost analysis shows that the 964 billion wons of benefits are greater than the 853 billion wons of total costs. Diesel retrofit programs could be one of the most effective measures to improve PM10 concentration in metropolitan area. But retrofit programs also need to be properly maintained by each vehicle.

• 한국가스학회지
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• 제27권3호
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• pp.91-97
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• 2023

오래된 디젤 엔진을 탑재하고 있는 노후화된 건설용 기계 및 차량들은 보통 수명이 길기 때문에 최신의 배기 규제와는 동떨어진 수준의 유해한 배출가스를 계속 배출하고 있다. 따라서 이러한 구형 디젤 엔진을 최신 배기 규제를 만족하는 엔진으로 대체할 수 있다면 대기질 개선에 도움이 될 것으로 기대되는데, 건설 현장에서 손쉽게 구할 수 있는 프로판 연료를 적용한 엔진이 적합한 대안이 될 수 있다. 따라서 본 연구에서는 6.8리터 CNG 엔진을 베이스로 프로판 전용 엔진을 개발하였으며, 가스 전용 인젝터, 배기가스재순환(EGR), 강화된 촉매 등의 기술이 적용되었다. 그 결과 동급의 디젤 엔진 출력 및 토크를 확보하는 한편 최신 배출가스 규제인 Stage-V 수준에서 질소산화물은 절반 수준에 해당하는 배출가스 성능을 달성하였다.

• 한국연소학회지
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• 제12권4호
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• pp.8-13
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• 2007

Plasma assisted combustion is an old subject for the combustion society, but recently, the subject is refocused partly because techniques for non-thermal plasmas are progressed significantly, and partly because there are lots of applications which need to be overcome by a new reaction technology. In the present study, we have developed plasma assisted burner (plasma burner), which can be used as a heating source in a diesel particulate filter system. The burner can burn 20-60 cc/min of diesel fuel with 50 lpm of fresh air in an exhaust pipe of 2.0 liter diesel engine. Using 20 cc/min of diesel fuel, an exhaust temperature for 2.0 liter diesel engine can be raised up to around $600^{\circ}C$ for a wide range of engine speed (idle-3,000 rpm). The characteristics of the plasma burner are reported, and the possible operating mechanism of it will be discussed based on the effects of an electric field and a plasma on flames.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2007년도 제34회 KOSCO SYMPOSIUM 논문집
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• pp.202-206
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• 2007

Plasma assisted combustion is an old subject for the combustion society, but recently, the subject is refocused partly because techniques for non-thermal plasmas are progressed significantly, and partly because there are lots of applications which need to be overcome by a new reaction technology. In the present study, we have developed plasma assisted burner (plasma burner), which can be used as a heating source in a diesel particulate filter system. The burner can bum 20 - 60 cc/min of diesel fuel with 50 lpm of fresh air in an exhaust pipe of 2.0 liter diesel engine. Using 20 cc/min of diesel fuel, an exhaust temperature for 2.0 liter disel engine can be raised up to around $600^{\circ}C$ for the range of engine speeds is idle - 3,000 rpm. The characteristics of the plasma burner are reported, and the possible operating mechanism of it will be discussed based on the effects of an electric field and a plasma on flames.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3335-3340
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• 2007

The government have been tightening EM regulation gradually but the effect is not good because of rapid increase of vehicles. And medium & heavy duty diesel vehicles, even though the number is small, exhaust very large pollutants(about over 50%). Especially it is more severe about old trucks and buses. Accordingly, CNG vehicle and the retrofit of diesel to CNG must be an alternative in order to protect the atmospheric environment and improve the air quality in the metropolitan area. The main object of this study is to secure the retrofit technology of diesel to CNG vehicle and the management system of CNG engine. we passed the government emission certification test. In addition to this, the mass production for retrofit is also studied. Results of emission and durability test for certification are as follows; there was no problem during 30,000km vehicle durability test and good emission levels satisfying the regulation.

• Journal of Advanced Marine Engineering and Technology
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• 제18권2호
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• pp.113-121
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• 1994

Since two oil shocks in 1970s, all of engine makers have persevered in their efforts to reduce specific fuel consumption and to increase engine power rate as much as possible in marine diesel engines. As a result, the maximum pressure in cylinders of these engines has been continuously increased. It causes direct axial vibration. The axial stiffness of crank shaft is low compared to old types of engine models by increasing the stroke/bore ratio and its major critical speed might occur within engine operation range. An axial damper, therefore, needs to be installed in order to reduce the axial vibration amplitude of the crankshaft. Usually the main critical speed of axial vibration for the propulsion shafting system with a 4-8 cylinder engine exists near the maximum continuous revolution(MCR). In this case, when the damping coefficient of the damper is increased within the allowance of the structural strength, its stiffness coefficient is also increased. Therefore, the main critical speed of axial vibration can be moved beyond the MCR. It has the same function as a conventional detuner. However, in the case of a 9-12 cylinder engine, the main critical speed of axial vibration for the propulsion shafting system exists below the MCR and thus the critical speed cannot be moved beyond the MCR by using an axial damper. In this case, the damping coefficient of an axial damper should be adjusted by considering the range of engine revolution, the location and vibration amplitude of the critical speed, the fore and aft vibration of the hull super structure. It needs to clarify the dynamic characteristics of the axial vibration damper to control the axial vibration appropriately. Therefore authors suggest the calculation method to analyse the dynamic characteristics of axial vibration damper. To confirm the calculation method proposed in this paper, it is applied to the propulsion shafting system of the actual ships and satisfactory results are obtained.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.139-145
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• 1997

Nowadays, the axial stiffness of crankshaft of long-stroke diesel engine is low compared to that of the old types of engine by increasing stroke/bore ratio and major critical speed might occur within engine operation speed. An axial damper needs to be installed in order to reduce the axial vibration of the crankshaft in the event of reduced or stopped axial damper function are discussed.

• Journal of Advanced Marine Engineering and Technology
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• 제16권5호
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• pp.17-28
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• 1992

During the last decade, engine makers have developed new types or increasing power rate engines to enlarge theirs marketing shear in two stroke, low-speed diesel engines. As the results, these engines have increased the additional stresses due to torsional vibration more than old model engines. The torsional vibration dampers are necessary in order to reduce heigher additional stresses of intermediate and crank shaft in these engine. In this paper, the optimum designing of Geislinger type torsional Damper has been carried out, based on the theoretical conception. The dynamic characteristics and performance fo dampers are estimated by the measuring results obtained with the monitoring system of dampers and additional stresses of propulsion shafts.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.243-247
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• 2004

The dynamometers which had made in a long time ago could not control the input/output quantity of water minutely and was sensitive to a noise since it was controlled by an analog control method. Therefore, a fully digital controlled system was urgently required to be robust against various noises. In this paper, the new system which can control the amount of circulated water in dynamometer was developed. This system is consisted of an industrial digital type controller and a servo motor. The industrial PLC was used as a main controller for the developed system, and the actuator and servo motor were used to control the inlet and outlet valve independently. The torque signal of load cell was fed back to the main controller to regulate the diesel engines load. Generally, an input/output valve position of the old dynamometer was fixed with a proper situation for an engine output test and the torque was changed according to the time interval. However, the torque value for the dynamometer could not be constantly kept because of the variation of the input water flow and fluid characteristic. Therefore, the automatic control of an inlet and outlet valve should be performed to keep the constant torque. So, the PID control method was applied to solve this problem. Also, the development of a web-based remote control system was described in this paper. This software will give us the convenience of operation, the more efficient operations, and the reduced operator workload for operation of the dynamometer. The application results of the system have been verified at actual diesel engine field.

• Journal of Advanced Marine Engineering and Technology
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• 제7권2호
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• pp.22-28
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• 1983

In former papers which were published already, authors had derived calculation formulae for the axial stiffness and the radial force conversion factor of crankshaft. In this paper, crankthrow axial stiffness and radial force conversion factors of actual engines are calculated by these theoretical formulae and then their characteristics are investigated. As the results, the axial stiffness and the radial force conversion factor of the latest super-long stroke engine are smaller than those of old-type engines. The influence of the former brings down the resonance speed of engine and the latter reduces the exciting force of axial vibration, but as the harmonic component of axial vibration force becomes rather strong, its effect of reducing is considerably canceled. In conclusion, as the latest super-long stroke engine is seemed to be liable to axial vibration of crankshafat, it is recommend that, in the design stage of propulsion shaft, its axial vibration condition must be more carefully checked.