• Journal of Advanced Marine Engineering and Technology
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• v.27 no.3
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• pp.405-411
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• 2003

An electric control fuel injector of a diesel engine injection systems is very important apparatus for fuel economy and emission control. It's performance was influenced by hydraulic contro1 of valve and solenoid especially the solenoid was important factor for operation and control of injector. In this paper. we made solenoids of 4 type. which changed the shape of armature and core. and measured magnetic force according to input current, and analyzed characteristics of solenoid on the shape through the test results.

• Journal of Advanced Marine Engineering and Technology
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• v.11 no.1
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• pp.53-62
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• 1987

The Performance of Pre-combustion Chamber Diesel Engine mainly depends upon the compression, combustion and Expansion Processes. The analysis of varying tendency of the work factors for crank angles during these processes, which are consisted of 5 items such as exothermic energy, flow work, work in nozzle part, kinetic energy and cooling energy, are considered important as basic elements for effective combustion and performance improvement. In this paper, varying tendencies of the theoretical factors are investigated with pressure data through experiments. By the results, the trends of work factors are presented as basic data for comparing the influencing effects on work.

• Journal of KSNVE
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• v.10 no.3
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• pp.465-473
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• 2000

In this crankshaft of marine diesel engines the exciting torques are produced by gas pressure and reciprocating masses. These torques are periodically changing and are extremely out of balance. To calculate the torsional vibrations of propulsion shafting caused by unbalanced torque the torque harmonics are utilized. Until now to calculate the torsional vibrations of propulsion shafting. the torque harmonics have been supplied by the engine maker. When the torque harmonics of an engine are not available the torque harmonics of a similar engine type had to be used. However such data is not suitable for the reliable calculations of torsional vibrations. In this paper the combustion characteristics of marine diesel engines including $\rho{-}\upsilon$ diagram are investigated and the torque harmonics based on these are theoretically calculated. reliability of the calculations is confirmed by comparing them with those of an engine maker. This study should prove useful for the calculations of torsional vibrations for diesel engine propulsion shafting. particularly for 4-stroke engines whose torque harmonics are difficult to obtain directly from the engine and not ordinarily supplied by the engine maker.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.7
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• pp.951-962
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• 2010

An experimental study was performed to investigate the improvement of response performance of a turbocharged diesel engine under the operating conditions of low speed and fast acceleration. In this study, the experiment for improving the low speed and acceleration performance is performed by means of injecting air into the intake manifold of compressor exit during the period of low speed and application of a fast acceleration from low speed. The effects of air injection into the intake manifold on the response performance were investigated at various applicant parameters such as air injection pressure, accelerating rate, accelerating time, engine speed and load. The experimental results show that air injection into the intake manifold at compressor exit is closely related to the improvement of turbocharger lag under low speed and accelerating conditions of a turbocharged diesel engine. During the rapid acceleration period, the air injection into the intake manifold of turbocharged diesel engine indicates the improvement of the combustion characteristics and gas pressure in the cylinder. At low speed range of the engine, the effect of air injection shows the improvement of the pressure distribution of turbocharger and combustion pressure during the period of gas exchange pressure.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.53-59
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• 2011

The using of diesel engine will be increased in the world for fuel economy. But diesel engine emits harmful emissions such as much NOx, smoke etc. In this study, experiments were performed to investigate the spray characteristics of diesel spray in a common-rail system according to fuel temperature, injection pressure, injection period and fuel viscosity etc. using a high speed video camera. Diesel oil has different spray patten due to injection pressure and injection period in a common-rail system. A Filter pressure was influenced by fuel temperature which was turned to fuel viscosity related to a fluid flowing. The effect of the bio-diesel fuel mixing ratio on the spray and atomization characteristics was also investigated at various experimental conditions. It shows that the droplet atomization characteristics of bio-diesel fuel showed deteriorated results as the mixing ratio of biodiesel increased because of the high viscosity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.945-951
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• 2012

A water emulsion fuel can be used to reduce soot and NOx emissions simultaneously because it has a lower combustion temperature and better fuel atomization owing to the evaporative latent heat and microexplosion of water. Moreover, it can be used without making special modifications to conventional diesel engines. Therefore, this fuel has attracted considerable research attention. In addition, lower-grade fuels are being considered for use in conventional engines because of an increase in oil prices. In this study, we investigated the combustion and exhaust characteristics of MDO (marine diesel oil), which has a lower grade than common diesel oil, and ME (MDO water emulsion) under various test conditions in an automotive diesel engine.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1816-1822
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• 2000

The maximum and mean indicated pressure of two stroke low speed diesel engine has been continuously increased with a view of increasing engine power and also reducing fuel consumption. As a result, axial excitation has been highed comparing to that of the previous and so in standard axial vibration damper is applied to all two stroke low speed diesel engine at the free end of crankshaft. Though many studies were carried out for marine use, few has been made for diesel power plant because there was little demand for power plant. Nowadays, diesel engine is much to be used for many benefits and so in this paper, the optimum design of axial vibration on the 65 MW diesel power plant with 9K80MC-S engine was carried out. And the axial-torsional coupled vibration of this shafting system is identified by theoretical analysis and vibration measurement.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1051-1056
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• 2014

Nitrous oxide ($N_2O$) is naturally generated from biological activity, such as bacteria's material exchange. However, recent $N_2O$ concentration in the atmosphere has being increased by the human activities such as industrial growth. One of factors to increase $N_2O$ concentration in the atmosphere is a $N_2O$ emission caused by the combustion of marine fuel oils. The marine transportation presently handles over 99 percent of the international freight cargoes and the number of ship is continuously increasing with increment of cargoes. In this study, author conducted a series of the experimental investigations on which combustion of fuels containing different element concentrations used in a 4-stroke marine diesel engine affect $N_2O$ emissions in the exhaust gas. Moreover, it is assessed on the extent to which fuel combustion patterns in the combustion chamber affect $N_2O$ emissions.

• Journal of Power System Engineering
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• v.21 no.6
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• pp.110-116
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• 2017

Recently the global warming caused by greenhouse gas has emerged as a global environmental problem. For this reason the continued efforts to reduce greenhouse gas emission by international cooperation and each country are in progress. Climate changing has been recognized as the world economy development from fossil fuel use is the culprit. The international maritime organization marine environment protection committee of the global warming reduction emerged restrictions on air pollution have been strengthened. Therefore, the author has investigated the effects of fuel temperature on the characteristics of combustion and performance, using an four-cycle, six cylinders and direct injection diesel engine. The results of cylinder pressure, rate of pressure rise, rate of heat release and specific fuel consumption were increased by changing of fuel temperature.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.195-205
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• 1997

The propulsion marine diesel engine have been widely applied with a mechanical- hydraulic governor to control the ship speed for long time. But it was recently very difficult for the mechani¬cal - hydraulic governor to control the speed of engine under the condition of low speed and low load because of jiggling by rough fluctuation of rotating torque and hunting by dead time of Desiel engnie The performance improvement of mechanical - hydraulic governor is required to solve these problems of control system. The electro - hydraulic governor using PID algorithm is provided to compensate the faults of mechanical- hydraulic governor. In this paper, in order to analyze the ship speed control system, the transfer function was converted from the z tansformation to w transformation. The influence of dead time changing by engine speed which induces hunting phenomena was investigated by Nichols chart of w plane. As a method of performance improvement of mechanical hydraulic governor, a Eletro - hydraulic governor shows that fine control results can be obtained through optimal parameter tuning of PID