바이오디젤은 동물성 유지, 식물성 유지와 그 부산물 등의 원료를 사용하여 지방산 메틸에스테르 형태로 제조된 연료이며, 석유계 에너지를 대체할 수 있는 바이오연료로 각광받고 있다. 그러나 바이오 디젤은 저장 및 유통 과정에서 불포화 지방산 메틸에스테르가 산화되면서 연료의 품질이 저하되거나 자동차 엔진부품을 부식시키는 등의 문제를 일으킨다. 따라서 본 연구에서는 바이오디젤의 품질과 산화 특성이 산화 안정성에 미치는 영향을 알아보고, 이와 관련된 평가 방법에 대해 기술하였다. 또한 바이오디젤의 산화 안정성 단점을 개선할 수 있는 방안을 고찰하였다.

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.

In this study, the applicability of biodiesel fuel was investigated as an hopeful alternative fuel for a compression ignition engine. The exhausted smoke emission of biodiesel fuel was reduced remarkably in comparison with commercial diesel fuel, that is, it was reduced approximately 64% at 2500 rpm, full load condition. And, torque, power and brake specific energy consumption rate did not showed significant differences. But, NOx emission of biodiesel fuel was slightly increased in comparison with the commercial diesel fuel. Generation of CO2 is considerably reduced by photosynthetic action in the course of growing biomass series plants, the material for biodiesel fuel.

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. CRDI (common rail direct injection) 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. An commercial CRDI diesel engine used to commercial vehicle was fueled with diesel fuel and 5% biodiesel blended fuel (BDF 5%) with city mode in excess of 300 hours. The engine performance and exhaust emissions were sampled at 1 hour interval for analysis. To check the engine parts (valve, injector), the engine was inspected after test. It was concluded that there was no unusual deterioration of the engine, or any unusual changes in engine power and exhaust emissions in spite of operation of 300 hours with BDF 5%.

In this study, the potential of biodiesel fuel and oxygenated fuel (ethylene glycol mono-n-butyl ether; EGBE) was investigated as an effective method of decreasing the smoke emission. The smoke emission of blending fuel (EGBE 0~20 vol-%) was reduced in comparison with diesel fuel and it was reduced approximately 64% at 2000 rpm, full load in the 20% of blending rate. But torque and brake specific energy consumption (BSEC) didn't have large differences. Also, the effects of exhaust gas recirculation (EGR) on the characteristics of NOx emission has been investigated. Consequently, it was found that simultaneous reduction of smoke and NOx was achieved with biodiesel fuel and oxygenated fuel(10%) and cooled EGR rates (5~10%) in a DI diesel engine.

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.

In this paper, the combustion characteristics of constant volume combustion chamber(CVCC) were experimentally investigated when biodiesel is mixed with pure gasoline. The experiment was performed on two gasoline biodiesel samples designated by GB05 and GB20 which is mixed with 5% and 20% biodiesel respectively. It was confirmed that the ignition delay time decreases as the temperature of injection engine increases due to ignition delay. Also, it was shown that the ignition delay time decreases as the biodisel mixing ratio increases from 5% to 20%.

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.

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.

Biodiesel as alternative energy source of the traditional petroleum fuels has increased interest, because environmental pollution based exhaust emissions from vehicle became serious. The advantage of biodiesel produced from esterification of vegetable and animal oils can be used without the modification of existing diesel engine, but glycerin is generated by production process. In this study, the usability of non-esterification biodiesel as an alternative fuel was investigated in a indirect injection diesel engine. The non-esterification biodiesel has not generated glycerin in esterification process and reduced the 20 percent of cost because it has not used methanol in the production process. Experiments were conducted by using the 5, 10 and 20 percentage of biodiesel and 4 and 8 percentage of biodiesel with 1 and 2 percentage of WDP in baseline diesel fuel. The smoke emission of biodiesel was reduced in comparison with diesel fuel, but power, torque and brake specific energy consumption was similar to diesel fuel.

Biodiesel as alternative energy source of the traditional petroleum fuels has increased interest, because environmental pollution based exhaust emissions from vehicle became serious. The advantage of biodiesel produced from esterification of vegetable and animal oils can be used without the modification of existing diesel engine, but glycerin is generated by production process. In this study, the usability of non-esterification biodiesel as an alternative fuel was investigated in a indirect injection diesel engine. The non-esterification biodiesel has not generated glycerin in esterification process and reduced the 20 percent of cost because it has not used methanol in the production process. Experiments were conducted by using the 5, 10 and 20 percentage of biodiesel and 4 and 8 percentage of biodiesel with 1 and 2 percentage of WDP in baseline diesel fuel. The smoke emission of biodiesel was reduced in comparison with diesel fuel, but power, torque and brake specific energy consumption was similar to diesel fuel.

바이오디젤은 지방산 중의 일부물질이 대기중의 산소와 결합하여 유기지방산 등을 형성하며 밀도, 동점도, 전산가, 산화안정도 등의 물성 특성에 영향을 준다. 바이오디젤의 산화안정성 문제를 해결 하기 위해 바이오디젤에 다양한 산화방지제를 첨가하여 물성 변화의 특성을 분석하였다. 첨가제의 함량 이 증가함에 따라 산화안정도는 증가하는 경향을 나타내고 대부분 첨가량에 비례적으로 증가하였다. 7 종의 첨가제 중 TBHQ가 가장 우수한 성능을 보이며 propyl gallate, butyl-amine, aniline, pyrogallol 등 4종의 첨가제도 목표치인 500 ppm 첨가 시 10시간 이상의 성능을 보였다. pyrogallol이 전산가에서 품질기준에 부적합하여 첨가제로서 적절하지 않은 것으로 나타났으며, hydroquinone계열의 TBHA, DTBHQ는 산화안정도에서 품질기준은 만족하나 연구과제의 목표치인 10 시간 이상에 미치지 못하는 결과를 보여 개발 첨가제로서는 결함이 있는 것으로 판단하였다. 또한 propyl gallate도 전산가에서 품질 기준에 적합하나 500 ppm 첨가 시 수치가 높고 첨가제 증가에 따른 전산가 증가 경향이 커서 첨가제 로서 부적합한 것으로 판단하였다.

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.

오늘날 지구온난화를 줄이기 위한 노력으로 온실가스 저감 기술 개발에 대한 노력이 정부차원에서 이루어지고 있으며 그 일환으로 국내에서는 2006년부터 자동차용 경유에 바이오디젤이 혼입되고 있다. 비록 일부 품질 기준상의 개선사항이 남아 있고 대부분의 원료를 수입에 의존하고 있다는 점에서 제한요소가 있음에도 2013년 기준 년간 400kton를 생산하고 있으며 향후 신재생에너지 연료 혼합의무화 제도(RFS)가 시행되면 그 생산양은 더욱 증가할 것으로 예상되는바 원료 다변화를 통한 원료 불균형 해소와 이에 따른 적절한 연구 개발이 필요하다. 본 연구에서는 신규 바이오디젤 원료로 검토되고 있는 라우릭산 메틸에스터(C12:0 FAME) 중심의 팜핵유(PKO, Palm Kernel Oil)와 코코넛유 유래 바이오디젤을 대상으로 국내 품질기준 중 차량 연소계통과 저온성능에 문제를 일으킬 수 있는 글리세린 함량 분석과 관련하여 기존 시험방법(KS M 2412)의 적용 가능성을 조사하였다. 이를 바탕으로 기존 분석조건에서 발생되는 카프릭산 메틸에스터(C10:0 FAME)와의 피크겹침, 총글리세린 도출관련 계산평형상수 등에 대한 개선 사항을 도출하고 보다 다양한 원료를 이용한 바이오디젤 내 글리세린 분석 가능한 시험방법 개발 가능성을 검토하였다.

Diesel vehicle is regulated EURO 5 and will be apply to EURO 6 in 2014. Thus, researches have been performed to meet the strict emission regulations. We have obtained that the results of engine performance operated by lard biodiesel at various engine load and speed was slightly decreased, but brake specific energy consumption (BSEC) at using animal biodiesel below 15% was better than diesel fuels. When the mixing ratio of biodiesel increased, NOx was a slight increase. But PM and CO was a significantly reduced. Therefore, that the biodiesel of animal fats is available for eco-friendly fuel of diesel engine was confirmed.