• 동력기계공학회지
• /
• 제18권6호
• /
• pp.106-112
• /
• 2014

The diesel engine, which has high compression ratio than other heat engines, has been using as the main power source of marine transport. Especially, since marine diesel engines offer better specific fuel consumption (SFC), it is environment-friendly compared to those used in other industries. However, attentio should be focused on emissions such as nitrous oxide ($N_2O$) which is generated from combustion of low-grade fuels. Because $N_2O$ in the atmosphere is very stable, the global warming potential (GWP) of $N_2O$ is 310 times as large as that of $CO_2$, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. It has been hitherto noted on the $N_2O$ exhaust characteristics from stationary power plants and land transportations, but reports on $N_2O$ emission from the marine diesel engine are very limited. In this experimental study, a author investigated $N_2O$ emission characteristics by using changed diesel fuel components of nitrogen and sulfur concentration, assessed on the factors which affect $N_2O$ generation in combustion. The experimental results showed that $N_2O$ emission exhibited increasement with increasing of sulfur concentration in fuel. However, all kinds of nitrogen component additives used in experiment could not change $N_2O$ emission.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.880-885
• /
• 2007

Diesel engines have been widely used in ships and power plants because of its higher thermal efficiency, mobility and durability compared to other prime movers. Though these merits, diesel engine including main components are sometimes vibrated due to higher combustion pressure in cylinders. Especially torsional, axial and structural vibrations in propulsion shafting may be severely manifested by the malfunction of torsional and axial dampers and misfiring and unbalanced load in cylinder. The structural vibration of main body and turbocharger core hole are also occurred by the loosen top bracing and excess wear-out or failure of turbocharger's bearings. The marine diesel engine should be safely designed from these vibrations. This paper introduces experimental methods to develop the prototype of integrated vibration monitoring system for marine diesel engine.

• Journal of Advanced Marine Engineering and Technology
• /
• 제37권1호
• /
• pp.47-52
• /
• 2013

최근 고유가 시대를 경험한 이후 에너지 수급에 대한 불안감이 증대됨과 동시에 지구온난화, 대기오염문제 등과 관련하여 대체에너지의 개발과 고효율 친환경 기술개발에 대한 요구가 강화되고 있다. 특히, IMO(국제해사기구)의 MEPC에서는 부속서 6을 $CO_2$의 규제법으로 하고자 하는 논의가 진행 중이다. 한편, 선박의 에너지효율을 향상시키고자 하는 다양한 기술들은 대부분 주로 새로운 기술의 개발과 신조선에의 적용에만 관심이 집중되고 있다. 그러나 선박기관은 일반적으로 장시간의 운항으로 그 성능은 점점 저하되고 운전조건 또한 변화되기 때문에 운항중인 기존선의 운항조건에 최적화된 기관의 운전관리야말로 친환경 및 고효율화 대책에 실질적이면서 매우 유익한 대책이 될 수 있다. 본 논문은 선박엔진의 성능저하정도를 정량적으로 예측하고자 하는 내용으로 엔진의 성능을 저하시키는 주요 인자들과 급기효율저하, 블로바이 가스증가 및 연료분사상태의 악화로 인한 연소악화 등이 엔진성능에 미치는 영향을 예측, 검토하였다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제28권2호
• /
• pp.309-314
• /
• 2004

The exhaust gas emission from marine diesel engines is one of the major environmental issues. The authors focus the use of photovoltaic energy for the electric power system on marine ships. This paper proposes an operation method of a photovoltaic/diesel hybrid generating system for a small ship in consideration of the fluctuating photovoltaic power due to solar radiation. The aim of the proposed operation method is to minimize the fuel consumption and storage capacity of the battery. The validity of the proposed control method is shown by the numerical simulation based on the experimental data of the photovoltaic system.

• Journal of Advanced Marine Engineering and Technology
• /
• 제35권6호
• /
• pp.829-834
• /
• 2011

본 논문에서는 대형 선박용 디젤 엔진의 실린더 라이너의 마모량을 측정하는 새로운 시스템의 개발에 관하여 소개한다. 제안된 시스템은 LVDT, 온도센서, 실린더 내부의 밝기조절용 LED 및 카메라가 각각 1개씩 부착된 측정부, 계측명령전달 및 측정데이터 모니터링을 담당하는 컴퓨터기반 모니터링부, 측정부의 제어 및 측정데이터의 모니터링부로의 전송을 담당하는 주 제어부로 구성된다. 개발된 시스템의 정도는 1/100 mm 의 측정정도를 갖는 내경게이지의 것과 비교되어진다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제32권8호
• /
• pp.1141-1148
• /
• 2008

One of the methods to increase the efficiency of an engine is to expand pressures obtained from combustions equal to the pressure of atmosphere as much as possible and then convert thermal energy into mechanical energy also as much as possible. In this research, the Diesel cycle was thermodynamically interpreted to evaluate the possibility of high efficiency by converting Diesel engines to the Atkinson cycle, and general cycle features were analyzed after comparing these two cycles. In the case of fuel air the Diesel-Atkinson cycle considering intake and exhaust similar to real cycles, the value of thermal efficiency and average effective pressure increased, though their values were smaller than those of standard air amount cycle, when expansion compression ratio increased. When normal Diesel engines of which compression stroke and expansion stroke are all the same, was converted to the Atkinson cycle by changing the time of intake value close, combustion pressure reduced due to reduced expansion compression ratio and intake air amount due to decreased effective cycle volume.

• 동력기계공학회지
• /
• 제18권6호
• /
• pp.113-119
• /
• 2014

Due to the development of the petroleum refining technology and continuously increased demand from markets, a quantity of gasoline and diesel oil produced from a restricted quantity of crude oil has been increasing, and residual fuel to be used at marine diesel engines has been gradually becoming low quality. As a result, it was recently reported that trouble oils which cause abnormal combustion such as knocking with extreme noise and misfire from internal combustion engines were increasing throughout the world. In this study, an author investigated ignitability and combustion quality by using combustion analyzer with constant volume(FCA, Fuel Combustion Analyzer) and middle speed diesel engine about MDO(Marine Diesel Oil), HFO(Heavy Fuel Oil), LCO(Light Cycle Oil) and Blend-HFO which was blended LCO of 1000 liters with HFO of 600 liters. Moreover, for betterment of ignitability and combustion quality of injected fuels, multi-injection experiment was carried out in the diesel engine using Blend-HFO. According to the results of FCA analysis, ignitability and combustion quality was bad in the order of MDO

• Journal of Advanced Marine Engineering and Technology
• /
• 제24권3호
• /
• pp.70-78
• /
• 2000

The effects of recirculated exhaust gas on the characteristics of ;$NO_x$ and soot emissions under a wide range of engine load have been experimentally investigated by a water-cooled, four-cylinder, indirect injection, four cycle and marine diesel engine operating at two kinds of engine speeds. The purpose of the present study is to develop the EGR control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions, and a novel diesel soot removal apparatus with a cylinder-type scrubber for the experiment system which has 6 water injectors(A water injector is made up 144 nozzles with 1.0mm in diameter) is specially designed and manufactured to reduce the soot contents in the recirculated exhaust gas to intake system of the engines. The intake oxygen concentration obtained by the intake air flow and the oxygen concentration in the recirculated exhaust gas, and the exhaust oxygen concentration measured in exhaust manifold are used to analyse and discuss the influences of EGR on NOx and soot emissions. The experiments are performed at the fixed fuel injection timing of $15.3^{\circ}$ BTDC regardless of experimental conditions. It is found that $NO_x$ emissions decrease and soot emissions increase owing to the drop of intake oxygen concentration and exhaust oxygen concentration as EGR rate rises. Also, one can conclude that it is sufficient for the scrubber EGR system with a novel diesel soot removal apparatus to reduce $NO_x$ emissions, but not to reduce soot emissions.

• Journal of Advanced Marine Engineering and Technology
• /
• 제19권3호
• /
• pp.24-32
• /
• 1995

The scavenging characteristics have a great influence on the performance of a diesel engine, especially slow-speed two-stroke diesel engines which are usually used as a marine propulsion power plant, and they are greatly affected by the conditions in the cylinder, intake and exhaust manifolds, and the opening and closing timing of scavenging ports or exhaust valves during the gas exchange process. Besides, there are many other factors to affect the scavenging characteristics and these factors interact each other very complicatedly. Therefore the simulation program of the gas exchange process is very useful to improve and predict the scavenging characteristics, due to the high costs associated with redesign and testing. In this paper it was attenpted to investigate the effect of the variation of the pressure ratio of intake to exhaust manifolds, and the variation of the opening and closing timing of a exhaust valve by using a computational program for a three-zone scavenging model which was developed by authors. The computed results showed that the scavenging efficiency and delivery ratio increased considerably, but the trapping efficiency decreased with increasing of the pressure ratio of intake to exhaust manifolds. The scavenging efficiency, trapping efficiency, and th conditions of the cylinder gases were affected by the opening timing of the exhaust valve, but the delivery ratio by the closing timing.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문집
• /
• pp.44-50
• /
• 2002

Theoretical analysis on the transient torsional vibration was started from early 1960's for high power synchronous motor application. As for marine engineering, simulation and measuring techniques of transient torsional vibration have been steadily studied by manufacturer of flexible coupling and designer of four stroke marine diesel engine. In this paper, the simulation method of transient torsional vibration for four stroke marine diesel engine application using Newmark method is introduced.