• Journal of Advanced Marine Engineering and Technology
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• 제24권5호
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• pp.16-24
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• 2000

In this study, using frying oil, performance of engine and emission concentration were compared with the case of using diesel oil. And results are as follows. 1. Engine torque and brake horse power indicate nearly same value as the case of using diesel fuel. 2. Temperature of exhaust gas was increased with as high engine speed and load. 3. To reduce concentration of hydrocarbon, it is effective to operate using used frying oil in low engine speed and load, and adding LPG in high engine speed and load. 4. Concerning with concentration of carbon mono oxide and smoke emission, it was assured, that as engine load increased, lower concentration emitted in case of utilizing mixed fuel than that of utilizing pure diesel fuel.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.659-673
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• 2021

This study aims to investigate the impact of the High Pressure Selective Catalytic Reduction system (SCR-HP) on a large marine two-stroke engine performance parameters by employing thermodynamic modelling. A coupled model of the zero-dimensional type is extended to incorporate the modelling of the SCR-HP components and the Control Bypass Valve (CBV) block. This model is employed to simulate several scenarios representing the engine operation at both healthy and degraded conditions considering the compressor fouling and the SCR reactor clogging. The derived results are analysed to quantify the impact of the SCR-HP on the investigated engine performance. The SCR system pressure drop and the cylinder bypass valve flow cause an increase of the engine Specific Fuel Oil Consumption (SFOC) in the range 0.3-2.77 g/kWh. The thermal inertia of the SCR-HP is mainly attributed to the SCR reactor, which causes a delayed turbocharger response. These effects are more pronounced at low engine loads. This study supports the better understanding of the operating characteristics of marine two-stroke diesel engines equipped with the SCR-HP and quantification of the impact of the components degradation on the engine performance.

• 수산해양기술연구
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• 제28권3호
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• pp.262-273
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• 1992

In this study, we selected a DC servo motor as an actuator of the marine diesel engine governor and constructed the position control system of the DC servo motor using the algorithm proposed by authors. Next, we proposed an another method to construct an adaptive control system for marine diesel engine by regarding the controlled system including the DC servo motor as a second order controlled system and verified the validity of this method through the real time control responses. Finally, the results have shown a good response characteristic.

• 동력기계공학회지
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• 제3권4호
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• pp.51-56
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• 1999

The ultrasonic method, which is well known as nondestructive test method, is widely used to evaluate the material damage due to degradation. However, this method is just used for measuring the crack size and the thickness loss of the tube. The purpose of this study is to investigate the applicability of the ultrasonic technique for the evaluation of marine diesel engine exhaust valve and to suggest the correlations between the ultrasonic characteristics and valve degradation. From the evaluation of the results obtained, the technique of using the ultrasonic property was founds to be a efficient method to evaluate the degree of marine diesel engine exhaust valve by nondestructive test.

• Journal of Advanced Marine Engineering and Technology
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• 제24권2호
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• pp.38-49
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• 2000

A diesel engine has been studied for many years to improve fuel economy and to reduce emissions as important factors governing the emission performance of diesel engines. This study addresses to swirl effects on combustion characteristics in a large diesel engine. The transport equations of flows and chemical reactions are given for fully compressible fluid. The simulations have been done for compression and expansion strokes and the results are given at several crank angles which are the angles at just before injection start, TDC, ATDC 90 and just before exhaust valve open. The results show that the strength of the swirl flow makes many effects on burning fuel and forming emissions.

• 한국해양공학회지
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• 제14권4호
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• pp.68-72
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• 2000

The ultrasonic method, which is well known as nondestructive test method, is widely used to evaluate the material damage due to degradation. However, this method is just used for measuring the crack size and the thickness loss of the tube. The purpose of this study is to investigate the application of the ultrasonic technique for the evaluation of marine diesel engine exhaust valve and to suggest the correlation between the ultrasonic characteristics and valve degradation. From the evaluation of the results obtained, the technique of using the ultrasonic property was founds to be a efficient method to degree of marine diesel engine exhaust valve by nondestructive test.

• Journal of Advanced Marine Engineering and Technology
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• 제23권5호
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• pp.693-699
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• 1999

In this paper author develops digital governor for medium speed diesel engine. The system is composed of MPU main control module RPM measuring module PWM driving module driver module for F.O. rack drive motor key pad and display module. Experiment results of speed control on 6cyl 1800pm 250kw Daewoo MAN diesel erigine were satisfied for design speci-fications and system could be developed for commercial usage after taking more experiments and endurance tests under various environments.

• Journal of Advanced Marine Engineering and Technology
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• 제19권3호
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• pp.9-23
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• 1995

To analyze the spray and flame in D.I. diesel engine, the visualizing methods by schlieren photograph and diffused background illumination photograph with high speed camera are applied to optically accessible D.I.diesel engine. Wcaporating spray, spray droplets and brightness flame are taken with high speed camera by visuallizing method in accordance with various suction air temperature and injection time. The spray and flame image on the film was analyzed by image analyzer. The optically accessible D.I. diesel engine had the similar pressure characteristic to the real D.I. diesel engine. Experimental results showed that shadow areas of the evaporating spray were extended at higher suction air temperature, spray droplets had a max. Penetration length and their penetrating patterns were dependent on the surrounding gas temperature, and flame size after ignition was largely governed by the evaporated fuel quantity at ignition point and by the surrounding gas condition due to piston motion.

• Journal of Advanced Marine Engineering and Technology
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• 제41권4호
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• pp.362-367
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• 2017

본 연구에서는 입자상물질 저감을 위해 개발한 디젤미립자 필터를 선박용 고속 디젤엔진에 적용하여 측정방법에 따른 저감효율을 비교 분석하였다. 시험에 사용된 엔진은 최고출력 403 kW의 4행정 기계식 선박용 고속 디젤엔진이며, 선박 엔진의 부하와 회전속도 제어를 위해 AC 동력계를 사용하였다. 선박 엔진 시험주기인 E3 cycle의 네 운전조건에서 저감효율을 측정하였으며, 측정방법으로는 입자상물질 및 soot의 저감특성을 살펴보기 위해 분류희석 방법과 광흡수법이 적용된 계측기를 각각 이용하였다. 디젤미립자 필터 적용에 따른 저감효율 측정 결과, 엔진허용 배압을 충족함과 동시에 입자상물질의 경우 76 ~ 91 %, soot(${\approx}$블랙카본)은 90 %이상 확인할 수 있었다. 이 결과로부터, 선박용 디젤엔진에서 배출되는 입자상물질 및 soot 저감기술로 디젤미립자 필터 적용 가능성을 확인할 수 있었다. 또한, 측정방법별 저감효율이 상이한 결과로부터 측정방법의 단일화 필요성을 확인할 수 있었다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 추계학술대회 논문집(Proceeding of the KOSME 2000 Autumn Annual Meeting)
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• pp.108-114
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• 2000

The excitation forces from the periodical firing pressure in cylinder and the rotating crank mechanism cause lots of vibration problems in diesel engine. In this paper, the theoretical formulas for excitation forces are introduced and computational program for the optimization of crank angle is also developed to reduce the free moments in diesel engine. The computational results of 4-stroke in-line engine are applied to verify the reliability of the program.