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 paper, we break away from the method of removing and inspecting the GDI injector, measure the pressure change of the fuel rail pressure sensor when driving the GDI injector of a vehicle equipped with the GDI fuel system, and compare the results. analyzed.There was a pressure change in the fuel rail pressure sensor from the general drive GDI injector. There was no pressure change in the fuel rail pressure sensor when driving the GDI injector without injecting fuel. You can check the fuel injection status in the pressure change data of the fuel rail pressure sensor without removal the GDI injector.

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 paper is one of basic studies for development of fuel rail to secure strength of GDI system. The fuel rail supports high pressure of 200~250bar and stores fuel while reducing pulsation during injection. Therefore, the structural characteristics of the conventional fuel rail was investigated with respect to stress and displacement. Then, the study focused on reducing stress concentration on fuel rail design to enhance the strength of each components. It was found that the maximum stress was not affected to the dimensions of taper lengths and angles of holes for fuel pipe. Also, it was found that the shape of holes for fuel pipe was key factor to reduce maximum stress, and the bridge between injector and mounting holder was effective structure to reduce the stress of injectors and displacement of the fuel rail system.

In this study, the effect of various pilot injection timings on combustion and emission characteristics were investigated in a common-rail direct injection (CRDI) diesle engine fueled with diesel-ethanol blends. The engine speed and engine load were controlled at constant 1500rpm and 70Nm, respectively. The tested fuels were DE0 (pure diesel fuel), DE5 (5 vol.% ethanol blended with 95 vol.% diesel oil), DE10 (10 vol.% ethanol blended with 90 vol.% diesel oil) and DE15 (15 vol.% ethanol blended with 85 vol.% diesel oil). The main injection timing was fixed at 0°CA TDC (top dead center), while various pilot injection timings including 25°CA BTDC (before top dead center), 20°CA BTDC and 10°CA BTDC were selected as the experimental variable. The experimental results showed that various pilot injection timings had little effect on the peak value of cylinder pressure, but had great influence on the start of combustion. The peak value of heat release rate (HHR) increased with the increase of ethanol content. However, the peak value of HRR reduced as the pilot injection is delayed. The diesel fuel containing 10% ethanol had a highest peak value of combustion pressure compared with the others, while the pilot injection timing occurred at 25°CA BTDC. On the other hand, the exhaust emissions of DE10 was also the lowest compared with the others. In addition, with the increase of ethanol content in diesel the PM and NOx emissions reduced.

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.

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.

In this study, we investigated the effects of EGR rate and engine load on the emission characteristics in a 4-cylinder common rail direct injection diesel engine fueled with canola oil biodiesel (BD) blended fuel. The biodiesel blend fuel, BD20 (20 vol.% biodiesel and 80 vol.% ULSD blend) was used at an engine speed of 1,500rpm. The experimental results showed that with the increasing of EGR rate, the combustion pressure and rate of heat release (ROHR) of three test fuels were decreased, and the ignition delay was extended, the carbon monoxide (CO) and particulate matter (PM) emissions increased slightly, but the nitrogen oxide (NOx) emission decreased clearly. On the other hand, with the increasing of engine load, the combustion pressure and ROHR were increased, and the CO and PM emissions decreased. However, the NOx emission was increased due to the rise of the combustion temperature.

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.

A demand for bio-diesel oil increases as one of solution for exhaustion of fossil fuel and reduction of CO2 emission, and research on bio-diesel is being carried out. Bio-diesel oil is mainly esterified from vegetable oil with methanol in order to use for fuel on diesel engine and has demerit that costs are increased as compared with directly using like non-esterified one. Bio-diesel oil within 3% mixed with gas oil is used at present, proportion of bio-diesel oil will be increase by 5% in future. We judged that wasted soybean oil non-esterified could be used on diesel engine with an electronic fuel injection according to previous researches with a mechanical fuel injection. A performance test using only gas oil, gas oil with esterified bio-diesel oil 5% and wasted soybean oil non-esterified 5% on diesel engine with the electronic fuel injection were carried out. It is noticed that gas oil with wasted soybean oil non-esterified 5% has more similar characteristics to gas oil than gas oil with esterified bio-diesel oil 5%.