• 수산해양기술연구
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• 제22권1호
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• pp.29-33
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• 1986

This paper aims at finding out the optimum operating condition to reduce fuel consumption for the training ship Pusan 402 with controllable pitch propeller. For this purpose, this paper examints the variation of ship speed and fuel consumption in accordance with the change of engine revolution and propeller pitch. The results obtained are as follows: 1. When engine revolution is constant, the ship speed sluggishly increases according to the increase of propeller pitch but fuel consumption extremely increases. The higher revolution the engine is, the more remarkable this tendency is. 2. As the engine revolution becomes lower, the fuel consumption per mile decreases. Howt.er = the fuel consumption under the same engine revolution differs according to the propeller pitch. 3. Specific fuel consumption is uniformed about 180g/ps.h at any case of load. 4. Among the various operating conditions which yield the same ship speed, fuel consumption lowers in the case of lower engine revolution and larger propeller pitch.

• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.579-583
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• 1997

A diesel Engine rotates vibratively because of alternative explosion strokes. Traditional measurement of a diesel engine speed is carried out by measuring output voltage of FV convertor from input signals of MPU(magnetic pickup unit) or of DC tachometer. Because these measurement include also vibrative rotation of a diesel engine, an analog filter is often used to eliminate high frequency noises due to periodic explosion stroke. But by this method these high frequency noises do not eliminated effectively because noise frequencies are changed according to diesel engine speed. In this paper, author proposes a new measurement method of a diesel engine revolution which read digital signal directly from MPU and prove the utility of proposed method through the real experiment.

• 한국안전학회지
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• 제10권4호
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• pp.13-21
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• 1995

On mini-bus with diesel engine, at idle rpm for taking measurement to reduce gear rattle noise, was tested by the three clutch disc samples by turns, then measured the fluctuation of revolution of engine & transmission and parallel vibration of differential gear & transmission. By analyzing the measured data, the gear rattle noise, the matching design and tuning technic of transmission are comprehended and established. Conclusions of this test are as follows ; (1) Fluctuation of revolution on transmission is greatly affected by torsion of clutch disc according to fluctuation of engine revolution transmit to transmission through clutch system. Especially, gear rattle noise can be reduced by minimaizing the fluctuation of the revolution of transmission using pre-damper type clutch disc. (2) The reason of gear rattle noise is higher in summer than winter and driving longer period than initial driving is due to affection by drag torque changing. So, it is necessary for manufacturer to choose proper oil to transmission. (3) It can be occurred jumping and crash noise by applying the pre-damper type clutch disc for reducing the gear rattle noise. So, it is necessary to do test with actual vehicle according to test procedure.

• Tribology and Lubricants
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• 제11권1호
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• pp.44-49
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• 1995

Friction characteristic of an engine crankshaft bearing is affected by revolution speed, applied loads, and viscosity of lubrication. So, experimental investigation is required to observe the friction characteristics using these factors. Hydraulic cylinder, servo controller system which can be modified the applied load, and test rig for the observation of the characteristics of engine crankshaft bearings were designed and fabricated, and some experiments were performed. Friction torque, journal locus and circumferential temperature variation of crankshaft bearing were measured according to applied load, revolution speed, and oil inlet temperature.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.618-621
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• 2004

Compressors in Large Multi-room air conditioning system are often driven by gas heat pumps. The advantages of GHP are their high level of heating performance and low cost because they use the LNG fuel to drive engine. We developed engine control system. The developed system controls engine speed based on proportional, integral and derivative (PID) method. This controller is designed to eliminate the need for continuous operator attention on engine revolution control. The control system includes 4 spark coil drivers, fuel drivers and relay drivers to make engine's operating more stable. The experiments of control engine revolution of this system are based on the various load conditions.

• 수산해양기술연구
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• 제35권3호
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• pp.323-327
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• 1999

Most of the underwater noise emitted by small fishing boat are owing to vibration of main engine and generator etc.. This paper describe on the spectrum analysis of underwater noise by engine generating in small fishing boat in order to build up comfortable environment for fisheries man and to reduce ambient noise. The obtained results are summerized as follows:1. When the underwater noise of 10ton class fishing boat measure and the frequency spectrum in varied revolution of engine 750, 900, 1000rpm analyze, the frequency pattern is similar to each other, the faster revolution of engine increase, the higher frequency spectrum level becomes. 2. In comparison of spectrum level of underwater noise between 10ton class and 14ton class fishing boat, the former level is higher than the latter. 3. Frequency spectrum pattern of two 14ton class fishing boat is similar to each other but spectrum level is a little difference, it is suggested to different by fitting condition of engine.

• 동력기계공학회지
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• 제5권3호
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• pp.17-24
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• 2001

In order to investigate a characteristic of the behavior of spray pattern in accordance with running conditions for a DI diesel engine, the PLN Injection system with changeable revolution speed of fuel injection cam was set up, and through this, history curves of injection pressure for a similar real DI diesel engine were able to be displayed. Authors visualized and analyzed the sprays at various revolution speed of fuel injection cam, and found out that fuel distributions of the sprays in the low speed condition were bad, fuel with air was injected from the hole of nozzle at the beginning of injection, and wide spray angle at the early stage of injection became narrower with elapsed time, but wider again at the end of injection.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.115-125
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• 2007

Minimizing the cylinder wear and the consumption rate of cylinder oil in a large two-stroke marine diesel engine is of great economic importance. In Korea, a motor-driven cylinder lubricator for a large two-stroke marine diesel engine manufactured by $W{\ddot{a}}rtsil{\ddot{a}}$ Switzerland Co., Ltd. was first developed by authors through the joint research of industry-university in 2002. The characteristic of the developed product is that can control automatically the oil feed rate to a load fluctuation by the motor drive and the offset cam. The performance of the product is not also inferior to the conventional one. For manufacturing the reliable and useful products, however, it is necessary to investigate further characteristics and improve the performance of a cylinder lubricator. In this study, the effect of quill with and without accumulator on maximum discharge pressure, delivery delay duration and oil feed rate relative to motor revolution speed using plunger stroke as a parameter is experimentally investigated by using the developed cylinder lubricator. It is found that the maximum discharge pressure with accumulator is higher than that of no accumulator as plunger stroke and motor revolution speed are elevated, and the delivery delay duration with accumulator is shorter than that of no accumulator as plunger stroke and motor revolution speed are increased. Also, oil feed rate with accumulator is less than that of no accumulator except for a plunger stroke of 2 mm as plunger stroke and motor revolution speed are raised.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.19-28
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• 2005

It is of great economic importance to minimize the cylinder wear and the consumption rate of cylinder oil in a large two-stroke diesel engine. The motor-driven cylinder lubricator was first developed fur a large two-stroke marine diesel engine made in $W{\ddot{a}}rtsil{\ddot{a}}a$ Switzerland Ltd. by the joint research of industry-university. In this study, the effects of revolution speed, plunger stroke and cylinder back pressure on maximum discharge and delivery pressures, delivery delay duration, and oil feed rate are experimentally investigated by the home-manufactured cylinder lubricator. The maximum discharge pressure with a spot of 0.03 m and the maximum loss pressure at spots of 5, 6.78 and i 0 m away from the end of lubricator slot are increased as plunger stroke, revolution speed and back pressure are elevated, and the delivery delay duration is shortened as plunger stroke, revolution speed and oil pipe length are increased. Also, oil feed rate is increased as plunger stroke and revolution speed are raised, but lowered as the back pressure is increased.

• 한국자동차공학회논문집
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• 제3권6호
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• pp.224-237
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• 1995

An ECU(Electronic Control Unit) with 16 bit microcomputer has been developed. This system includes hardware and software for more precise control on fuel injection, ignition timing, and idle speed. This control system employs an air flow sensor of the hot wire type, a direct ignition system, an idle speed control system using a solenoid valve, and a crank angle sensor. Especially, the crank angle sensor provides two separate signals: One is the position signal(POS) which indicates 180 degree pulses per revolution, and the other is the reference signla(REF) that represents each cylinder individually. The conventional engine control system requires at least two engine revolutions in order to identify the cylinder number. However, the developed engine control system can recognize the cylinder number within a quarter of an engine revolution. Therfore, the developed engine control system has been able to control fuel injection and ignition timing more quickly and accurately, Furthermore, the number of misfire reduces during the cold start.