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.

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.

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.

In this study, we investigated the effects of diesel-palm oil biodiesel-ethanol blends on combustion and emission characteristics in a 4-cylinder common rail direct injection (CRDI) diesel engine at low idling operations. The engine speed and engine load was 750 rpm and 40 Nm, while the main and pilot injection timing was respectively fixed at 2 °CA before top dead center (BTDC) and 20 °CA BTDC. The experimental results showed that the cylinder pressure increased with the increasing of palm oil biodiesel ratio from 20% to 100%. In addition, the peak value of cylinder pressure increased by 4.35% compared with pure diesel fuel when 5 vol.% ethanol oil added to diesel oil. Because the palm oil biodiesel and ethanol are the oxygenated fuel, the oxygen content played an important role in improving combustion. Based on the high oxygen content of biodiesel and ethanol, their mixing with diesel fuel effectively reduced PM emissions but increased NOx slightly, while CO and HC had no significant changes.

This study describes the effects of palm oil biodiesel (PD) blended with diesel on the combustion performance, emission characteristics and soot morphology in a 4-cylinder CRDI diesel engine. 5 kinds of fuels are used with blending as diesel/biodiesel volume ratio 0%, 10%, 20%, 30%, 100%. The engine is operated under idle speed, 750rpm and load conditions of the engine are 0 Nm and 40Nm. The Coefficient of Variation(COV) of Indicated Mean Effective Pressure(IMEP) shows that the engine operates very steadily in the idle state. But fuel consumption is increased. And Emission results show that the oxygen in biodiesel has a great influence on the production of exhaust emissions. The nitrogen oxides(NOx) is decreased because of high viscosity and low heating values of biodiesel at low blend ratio. But NOx and Carbon monoxide(CO) are increased above a certain blend ratio. Particulate matter(PM) and Hydrocarbons(HC) is decreased according to increase of blend ratio. The size of soot is decreased and the morphology of soot is developed to cluster with increasing blend ratio.

The diesel engine is excellent in economic and thermal efficiency, and is widely used as a power source for industries and automobiles. However, the problem of environmental pollution caused by exhaust gas has recently become serious and the development of alternative energy resources is urgently required due to depletion of fossil fuel. Because biodiesel is similar in properties to light oil, it is being used as fuel for diesel engines by replacing or mixing conventional light oil. As the blending of biodiesel fuel in diesel increases, the emission of harmful substances is decreased as compared with the general diesel fuel, and the supply is increasing. In this study, the effects of biodiesel fuel on engine power and exhaust gas were investigated, and empirical formulas for various NOx and Smoke exhaust gases were derived based on biodiesel blending fuel.

Biodiesel fuel (BDF) can be effectively used as an alternative fuel in diesel engines. The BDF, however, may affect performance and exhaust emissions of the diesel engine because it's physical and chemical properties are different with from the diesel fuel such as viscosity, compressibility and so on. To investigate an effect of injection timing on characteristics of performance and exhaust emissions with the BDF in an IDI diesel engine, this research applied the BDF derived from soybean oil in this study. The engine was operated with six different injection timings from TDC to BTDC 12 ˚CA and six different loads at the engine speed of 1500 and 2000 rpm. In less then the BDF 20, it showed the similar trend compare to the diesel fuel. But, the best injection timing was 2˚CA retarded compare to the diesel fuel with BDF 50.

전통적인 화석 에너지 자원의 고갈과 환경오염 악화 등의 관점에서 볼 때 에너지 절약 및 배출가스의 저감은 동시에 해결해야 되는 문제로 대두되고 있다. 바이오연료는 대체연료의 하나로서 이러한 문제들을 효과적으로 해소할 수 있는 대안으로 떠오르고 있다. 따라서 본 연구에서는 커먼레일 터보과급디젤기관에서 카놀라유 바이오디젤연료의 적용효과를 알아보기 위하여 실험적으로 고찰하였다. 실험에 사용된 연료는 ULSD(초저황 디젤유), BD20(체적비로 20%인 카놀라유와 80% 디젤유 혼합) 및 PCO(순수한 카놀라유)를 사용하였다. 카놀라유 바이오디젤연료의 혼합율이 증가함에 따라 입자상물질(PM)과 일산화탄소 (CO)는 크게 감소하였으며, 질소산화물(NOx)은 약간 증가하는 현상을 보였다.

This study describes the effects of canola oil biodiesel (BD) blended fuel on the combustion performance and emission characteristics in a 4-cylinder common-rail direct injection diesel engine. In this study, with the increasing of engine loads, the biodiesel blend fuels(100 vol.% ULSD and 0 vol.% biodiesel blend, BD0; 80 vol.% ULSD and 20 vol.% biodiesel blend, BD20; 0 vol.% ULSD and 100 vol.% biodiesel blend, BD100; ULSD: ultra low sulfur diesel) were used at an engine speed of 1,500rpm. The experimental results showed that with the increasing of biodiesel blend rate, the combustion pressure decreased slightly at engine load of 20~60Nm. However, the rate of heat release (ROHR) increased clearly and ignition delay time was shortened. With the increasing of biodiesel blend rate, the carbon monoxide (CO) and particulate matter (PM) emissions were more decreased at all of the engine loads.

최근 지구 온난화는 세계 경제발전으로 화석연료 사용이 주범으로 인식하고 있다. 이러한 화석연료를 감소하기 위한 연구는 여러 대체에너지 산업으로 발전하고 있으며, 그 중 우리나라에서 생산할 수 있는 연료는 바이오연료이다. 바이오연료는 화석연료에 의해서 발생하는 환경오염 문제를 줄이면서 경제적인 이익을 주는 지속 가능한 연료이다. 그래서 바이오연료를 친환경에너지로 전환시키는 재생에너지 등에 많은 연구가 진행되고 있다. 따라서 본 실험은 어선에서 사용했던 기관을 다시 리모델링하여 실험장치를 직접 제작 설치하였고, 여러 바이오연료를 사용하여 선박의 경제적이고 친환경적인 운항에 도움을 주고자 연구하였다. 유채유, 대두유, 폐유채유의 배기배출물특성에 미치는 영향을 종합적으로 분석한 결과는 연료의 물리적, 화학적 성분이 비슷하여 선박용 엔진에 사용이 가능하고, 연료소비율과 NOx는 약간 증가하였으나, 매연은 많이 감소하는 경향이 확인되었다.

Injection rate characteristics of biodesel fuels according to the blending ratio was described in this work. The injection rate measuring system based on the Bosch's method was utilized to measure and compare the fuel injection rate characteristics. Three different types of biodiesel which were derived from seed, unpolished-rice, and soybean were blended with the diesel fuel in 20% and 40% of volumetric ratio. The fuel properties, injection mass, and injection rate characteristics were obtained and compared in various injection conditions. It is expected that this observations provide important insights into the effect of fuel properties on the biodiesel fuel injection rate performance in a CI engine

최근 바이오디젤의 보급 활성화에 정책에 따라 석유제품에 바이오디젤 혼합량이 증가되고 있으며, 이러한 혼합량 증가에 따른 겨울철 저온특성과 산화안정성에 대한 문제가 제기되고 있다. 따라서 본 연구에서는 바이오디젤 혼합연료에 대하여 실제 저장환경을 모사하고, 저장 중 품질변화를 평가하여 저장환경별 산화 경향과 품질에 미치는 영향 등의 규명을 통해 산화 제품의 품질관리 방안을 제시하였다. 바이오디젤 혼합연료의 산화열화 평가 결과, 직접적인 햇빛 노출 및 대기노출이 없는 저장용기에서는 여름철 약 18주간은 산화에 의한 특별한 품질저하는 없었지만, PE 재질 플라스틱 용기의 경우 약 2주간의 햇빛노출에 급격한 산화가 일어나 품질저하를 초래하였다. 이러한 현상을 일부 품질변화뿐만 아니라 FT-IR 스펙트럼 변화로도 확인 할수 있었다. 하지만 산화가 상당히 진행된 연료라도 품질기준을 모두 만족하여 품질검사 항목만으로는 특별한 현상을 발견할 수 없었다. 즉, 품질기준을 만족하더라도 산화로 인한 산화 생성물(고분자물질, 유기산 등)에 의해 차량 문제를 유발할 수 있는 충분한 여지가 있었다.

바이오디젤은 식물성유지, 동물성유지 그리고 폐식용유를 전이에스테르화 반응을 시켜 만들어진 것으로 경유를 대체할 수 있는 연료이다. 본 연구에서는 다양한 원료의 식물성유지 (대두유, 폐식용유, 유채유, 면실유, 팜유)로부터 얻어진 바이오디젤의 연료 특성을 알아보았다. 다양한 식물성유지 원료로부터 얻어진 바이오디젤은 지방산메틸에스테르 함량, 동점도, 인화점, 필터막힘점, 글리세린 함량을 분석하였다. 바이오디젤의 품질기준과 시험방법은 한국 표준과 유럽 표준인 EN14214에 따라 시험하였다. 대두유, 폐식용유, 유채유, 면실유 바이오디젤은 불포화지방산이 많이 포함되어 있는 반면에 팜유 바이오디젤은 포화지방산이 많이 함유되어 있다. 저온특성, 동점도, 산화안정도와 같은 바이오디젤의 연료 특성은 지방산메틸에스테르의 구성 성분과 관련이 깊다.

Hydrotreated biodiesel(HBD) is paraffinic bio-based liquid, with the chemical structure CnH2n+2, originating from vegetable oil(the process can also be applied to animal fat). The oil or fat is treated in a number of process, the most important being hydrogenation, in order to create a bio-based liquid diesel fuel. During the hydrogenation, oxygen is removed from the triglyceride and converted into water. Propane is formed as a by product and can be combusted and used for energy production. HBD can be used in conventional diesel engines, pure or blended with conventional diesel, due to its similar physical properties to diesel. This study reports the quality characteristics with chemical and physical properties as an alternative diesel fuel. Especially, HBD showed higher cetane value and number than FAME, and it is consisted of C15 - C18 n-paraffinic compounds. We also describes quality characteristics of HBD blends(2, 5, 10, 20, 30, 40, 50 vol%) in automotive diesel. HBD blends(max. 20 vol%) were the limit by the Korean specification due to poor low temperature characteristics.

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions of diesel engines are recognized as main causes of the air pollution. DI diesel engine is widely used for the sake of minimization on exhaust emission. Because biodiesel fuel is a renewable and alternative fuel for diesel engine, its usability is expanded. The smoke emission of esterfied rapeseed oil is reduced remarkably in comparison with commercial gas oil, that is, it was reduced approximately 44.5% at 1500rpm. But, brake specific energy consumption showed very slight differences. It was concluded that esterfied rapeseed oil can utilize effectively as an alternative and renew-able fuel for diesel engine.