This study aims to optimize the SDC (Spinning Dust Collector) system in amphibious assault vehicle engines through numerical analysis of dust and moisture particle separation efficiency using CFD-DPM. Focusing on an axial cyclone structure, the research evaluates separation efficiency across various particle sizes and flow conditions. The results demonstrate that vortices generated by cyclone blades play a critical role in influencing particle trajectories and improving separation performance. Additionally, the study highlights the significant impact of engine flow conditions and housing design, emphasizing that their careful optimization enhances the system's efficiency in separating dust and water. These findings offer valuable insights into optimizing inlet and outlet flow paths and cyclone housing design, providing a solid foundation for advancing SDC system performance in high-efficiency engines.

Recently marine accidents involving floating objects have been continuously increasing due to domestic coastal traffic conditions, and as a result cases of secondary-linked reduction gear damage have also occurred one after another. This research aims to evaluate the ship propulsion system safety through the analysis the effect of the torsional stress generated on the propeller shaft system when a rope or net is wrapped around a propeller at sea through theoretical analysis, simulation analysis, and ship empirical test.

Biodiesel is a traditional energy field that can replace low-quality marine fuels for ships and various studies have been conducted. Since the 2000s, Korea has introduced a mandatory supply system of biodiesel for domestic vehicle diesel, gradually raising the blending ratio from 0.5% to 3.5%, and is expected to raise the mandatory blending ratio to about 8.0% by 2030. Therefore, in this study attempted to blend high-quality samples that meet the biodiesel quality standards manufactured by domestic companies with MGO in ratios ranging from 0 to 60%. We utilized a 1-ton combustion chamber to compare and analyze the exhaust gas emissions characteristics. As a result, in the BD60 condition, which represents the maximum range in this study, the O2 increased by approximately 1.5%p, and CO2 tended to decrease by 1.1%p. NOx decreased by approximately 18.2%p from 34.1 ppm to 27.9 ppm. In the case of SOx, a very low concentration of 0.08 ppm was detected under the BD0 condition, and it was undetectable under all other conditions containing biodiesel. This suggests that MGO itself has excellent low-sulfur oil quality and can implement zero SOx through biodiesel mixing. Furthermore the combustion efficiency decreased by approximately 1.91%, from 72% to 70.2%, and the exhaust gas temperature also decreased by about 4.5%p. However despite the lower calorific value of biodiesel compared to MGO, it demonstrated relatively close thermal output per unit content. This indicates sufficient potential for biodiesel to serve as a viable alternative fuel for ships in the future.

In this study, when Butyl ether, a type of diether-based oxygenated fuel, is mixed in each volume ratio in a naturally aspirated direct injection diesel engine, the exhaust gas emission characteristics of the oxygenated component in the fuel affect each operating area of the engine I wanted to investigate the effect on. For comparative measurement of engine performance and exhaust emissions, commercial diesel and butyl ether mixed fuels were classified into 4 types according to the mixing ratio and tested. As the content of butyl ether in fuel increases, soot emission reduction increases, and when the maximum mixing amount of butyl ether (diesel 80vol-% + BE 20vol%) is applied, compared to the case of using only diesel as fuel, at 2500 rpm and no load, 39%, and about 32% of smoke reduction effect at full load was confirmed.

본 연구에서는 소형선박용 중·고속 디젤엔진에 적용하여 연구 중인 SCR+DPF 기술을 저속엔진이 설치된 선박에 탑재하여 해상 실증 시험을 수행하였다. 대상 선박(총 톤수 2,881 톤, 정격출력 1,470kW@240rpm ×1)은 국내 연해를 운항하는 일반화물선으로 배출저감설 비의 선박 탑재를 위해 도면 개발, 승인 및 선박 임시검사를 수행하였다. 저감성능 확인을 위해서 가스상물질 측정장비는 NOx technical code 및 ISO-8178의 분석방법을 준용하는 장비를 사용하였으며, 입자상물질 측정장비는 국제해사기구(IMO)에서 논의하고 있는 블랙카본 측정 방법 중 하나인 스모크미터를 사용하였다. 시험은 황 함유량 따라 MGO(0.043%), LSFO(0.42%) 2종의 연료를 사용하였으며 실제 운항 하는 엔진회전수(130, 160 및 180 rpm)를 고려하여 시험 조건을 설정하였다. 시험 조건에 따라 배출저감설비의 전·후단에서 가스상 및 입 자상(매연) 물질을 측정하여 배출저감설비의 저감효율을 확인하였으며 모든 시험 조건에서 NOx의 경우 90% 이상, 입자상물질(매연)의 경우 95% 이상의 저감효율을 확인하였고 엔진 성능의 영향을 줄 수 있는 배기가스 압력은 허용배압 기준인 50mbar 이하를 만족하였다. 본 연구를 통해 해상실증 연구의 중요성과 중소형 저속엔진 선박의 질소산화물 및 입자상물질의 동시 저감을 위한 대응 기술로 SCR+DPF 설비 적용 가능성을 확인할 수 있었다.

바이오디젤은 중립연료로써 친환경 연료로 알려져 있으며, 육상에서는 일정 비율을 의무 혼합하는 정책을 시행하고 있다. 본 연구에서는 바이오디젤의 선박 연료로써의 사용 가능성을 검증하기 위해 선박용 경유와 바이오디젤의 혼합비율 0 %, 5 %, 10 %, 20 %에 대해 성분 분석, 금속 부식성 실험, 저장 안정성 실험을 수행하였다. 성분 분석은 ISO 8217:2017 기준에 따라 밀도, 동점도, 인화점 등 총 8가지를 평가하였으며, 180일 동안 상온과 가혹 조건(60 ℃)에서 금속 부식성 실험과 저장 안정성 실험을 통해 바이오디젤 신뢰성을 검증 하였다. 연구 결과, 성분 분석은 바이오디젤 모든 혼합비율에서 ISO 8217:2017 기준을 만족하였으며, 바이오디젤 비율에 따라 동점도, 밀 도, 산값은 혼합비율이 높아질수록 높게 나타났으며, 황분은 혼합비율이 높아질수록 낮게 나타났다. 금속 부식성은 탄소강, 철, 알루미늄, 니켈의 경우 부식이 거의 발생하지 않았으나, 구리의 경우 60 ℃ 환경 바이오디젤 20 % 혼합에서 산소가 풍부한 바이오디젤의 영향으로 부식이 발생하였다. 저장 안정성은 모든 바이오디젤 혼합비율을 180일 동안 상온과 가혹 조건에서 저장한 결과, 변색, 슬러지 발생, 연료 분리가 육안으로 확인되지 않았다.

Failure diagnoses on large diesel engine are commonly detected when a deviation or fluctuation in its temperature, pressure, vibration or noise set parameter limits arises. These parameters can be easily monitored and can provide information of the engine’s present state depending on external environment and operating conditions. On the other hand, long term monitoring and condition management can be interfaced into the engine’s existing operating system. The approach is seen to keep track of monitored machines’ status using resonance and vibration amplitude. In particular, these signals will be able to identify complex vibration characteristic pertaining to such as engine torque output and support mounts. In this paper, a basic research for large diesel engine diagnosis was carried-out. The failure diagnosis collects and monitors the vibration state time history by using various vibration signals with reference to ISO 13373-1. Further, this monitoring system in the field of large diesel engines has not been applied practically and the results of this study are presented herein.

국내 대기오염물질 배출량 통계에 따르면 상당한 대기오염물질이 선박에 의해 발생하고 있다. 따라서 선박으로부터의 대기오 염물질 배출 제한과 항만지역 대기질 개선을 위해 다양한 정책들이 시행되고 있고, 국제적으로도 선박에 의한 해양오염 방지를 위해 국 제 협약 등이 이루어지고 있다. 하지만 실제 운항하는 선박에서 배출되는 대기오염물질 측정에 관한 연구와 실험은 거의 이루어지고 있 지 않아, 본 연구는 이동식배출가스측정장비(PEMS)를 사용하여 실제 운항하는 9,169톤급 선박에서 발생하는 대기오염물질 배출량 평가에 대한 방법과 가능성을 제시하였다. RPM과 부하에 따라 배출량의 차이가 있었으며, NOX 배출량은 497-2,060ppm, CO2는 1.55-6.9%, CO는 0.002-0.14% 수준이다. 엔진 제조사에서 제공하는 Shop Test에 명시된 배출량과 실제 측정된 배출량에 차이가 있음을 확인하였다. 대상선박 의 전 항해구간에서 발생하는 각 대기오염물질 최대 배출량이 PEMS 측정 구간에 포함되는 것을 확인하여, 총톤수 10,000톤급 이내 선박 에 PEMS 활용 가능성을 검증하였다.

This study compared and analyzed the difference in performance between the existing soot probe and the improved one that was applied to the actual inspection vehicle at the actual inspection site, which has been developed under the specific conditions based on the excellent results through the performance evaluation. As the results, probe(b) involves a structure designed close to the center of the circumference of the exhaust pipe, and the suction efficiency was improved by adding a center unit. The improved probe(b) can enhance the effectiveness of the inspection when applied to total and regular tests inspections, and the possibility of contributing to the reduction of carbon dioxide emissions generated in the transportation sector has been confirmed.

Diesel engine has the advantages of strong power, low fuel consumption and good durability, so it has been widely used in transportation, automobile, ship and other fields. However, the nitrogen oxides(NOx) and particulate matter(PM) emitted by diesel engines have become one of the main causes of air pollution. Especially during idling, the engine temperature is low, and there are more residual exhaust gases in the combustion chamber, resulting in the formation of more harmful emissions. In this study, performance of a single cylinder, four-stroke, direct injection (DI) diesel engine fueled with diesel–biodiesel mixtures has been experimentally investigated. The findings show that a remarkable improvement in PM–NOx trade-off can be achieved by burning diesel-bioethanol blend fuels.

Diesel engine has the advantages of strong power, low fuel consumption and good durability, so it has been widely used in transportation, automobile, ship and other fields. However, the nitrogen oxides(NOx) and particulate matter(PM) emitted by diesel engines have become one of the main causes of air pollution. Especially during idling, the engine temperature is low, and there are more residual exhaust gases in the combustion chamber, resulting in the formation of more harmful emissions. In this study, performance of a single cylinder, four-stroke, direct injection (DI) diesel engine fueled with diesel–biodiesel mixtures has been experimentally investigated.

The emergency diesel generator of a nuclear power plant is a emergency AC power source that starts up within 10 seconds when a LOOP(Loss Of Off-site Power) occurs and supplies power to essential safety facilities. In this study, factors affecting start signal input time, engine rotation start time, 30% of engine rated speed, 80% of engine rated speed were studied to secure starting reliability. As a result, it was found that the section before the 30% of engine rated speed was affected by the mechanical management status from the start signal to the fuel oil linkage system. After the 30% of engine rated speed section, it was the maximum fuel supply section, and the time reduction effect through management improvement was insignificant.

A Emergency Diesel Generator(EDG) in Nuclear Power Plant supplies electrical power to reactor cooling system when on/off site power is lost. So that protect the reactor from melting down. A Emergency Diesel Generator is required to reach ±2% of rated frequency(rotational speed) within 10 sec. To achieve prompt start, it is needed to find out affective factors and effect of that during starting period. This paper describes case of fail to achieve starting requirement and improvement of starting performance.

The purpose of this study is to require countermeasures for alternative energy of diesel combustion engines, which has a serious impact on air pollution when using the quantitative limit of petroleum-based energy and transportation energy. This study attempted to study the usefulness of the oxygen component in fuel as a measure to reduce exhaust emissions from diesel engines used in reality. Dimethoxy methane (DMM), which contains about 42% oxygen in itself, was mixed with diesel and applied to a diesel engine. As a result of the study, it was confirmed that as the oxygen content in the fuel increased, smoke was greatly reduced and NOx increased.

In this study, the effects of fuel injection pressure changed from 45 to 65 MPa on combustion and emission characteristics were investigated in a common rail direct injection (CRDI) diesel engine fueled with diesel and palm oil biodiesel blends. The engine speed and engine load were controlled at constant 1700rpm and 100Nm, respectively. The tested fuel were PBD20 (20 vol.% palm oil biodiesel blended with 80 vol.% diesel fuel). The main and pilot injection timing was fixed at 3.5°CA BTDC and 27°CA BTDC (before top dead center), respectively. The experimental results show that the combustion pressure and heat release rate increased. In addition, the indicated mean effective pressure (IMEP) and maximum combustion pressure increased with an increase of the fuel injection pressure. Hydrocarbon (HC), smoke opacity and carbon monoxide (CO) decreased, but oxides of nitrogen (NOx) emissions increased as fuel injection pressure increased.