In the past, the U.S. NRC(Nuclear Regulatory Commission) strictly required testing of the EDG for NPP through Reg.Guide 1.108 Rev 1. However, these test requirements acted as a deterioration and wear factor for diesel engines, and are now applying Reg.Guide 1.9 Rev 3, which relaxed regulatory requirements and improved performance monitoring. After applying the new regulatory guidelines in this study, the EDG analyzed the performance of the combustion chamber. As a result, there were no signs of deterioration or decreased performance of the current EDG. This is due to slow start, short operation time, the use of high quality fuel oil and proper maintenance. On the other hand, if the performance is proven, it is judged that proper period extension of cylinder maintenance is possible.
In this study, to investigate the effect of physical and chemical properties of butanol on the engine performance and combustion characteristics, the coefficient of variations of IMEP (indicated mean effective pressure) and fuel conversion efficiency were obtained by measuring the combustion pressure and the fuel consumption quantity according to the engine load and the mixing ratio of diesel oil and butanol. In addition, the combustion pressure was analyzed to obtain the pressure increasing rate and heat release rate, and then the combustion temperature was calculated using a single zone combustion model. The experimental and analysis results of butanol blending oil were compared with the those of diesel oil under the similar operation conditions to determine the performance of the engine and combustion characteristics. As a result, the combustion stabilities of D.O. and butanol blending oil were good in this experimental range, and the indicated fuel conversion efficiency of butanol blending oil was slightly higher at low load but that of D.O. was higher above medium load. The premixed combustion period of D.O. was almost constant regardless of the load. As the load was lower and the butanol blending ratio was higher, the premixed combustion period of butanol blending oil was longer and the premixed combustion period was almost constant at high load regardless of butanol blending ratio. The average heat release rate was higher with increasing loads; especially as butanol blending ratio was increased at high load, the average heat release rate of butanol blending oil was higher than that of D.O. In addition, the calculated maximum. combustion temperature of butanol blending oil was higher than that of D.O. at all loads.
In recent years, the regulation of exhaust gas of automobiles has been strengthened, and various high-tech technologies have been applied to cope with exhaust gas regulations. Especially, in case of gasoline vehicles, by injecting gasoline direct injection, a large amount of carbon deposits are adsorbed in intake / exhaust valves and combustion chambers, Which is a cause of combustion. Therefore, in this study, we developed the cleaning liquid and related special tools to remove carbon deposits in the combustion chamber, and developed the cleaning process of the combustion chamber and tried to understand the effect on the engine performance improvement. In order to prevent the release of heavy metals after burning, the cleaning effect of the cleaning liquid was investigated by temperature and the influence of the knocking of the engine on the cleaning performance.
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.
This study was performed to investigate the effect of fuel combustion enhancing apparatus(FCEA) for ionization of intaking air into cylinder combustion chamber on the combustion performance and emissions characteristics in a 4-cylinder common-rail direct injection diesel engine. The experiments were applied to the engine at an engine speed of 1,500rpm under 20Nm, 40Nm, 60Nm and 80Nm conditions. The test results were compared to each other with or without the FCEA. In the case of the FCEA, the combustion pressure, peak combustion pressure and rate of heat release were increased slightly and the brake specific fuel consumption(BSFC) was decreased slightly when compared to that without the FCEA under all loads at an engine speed of 1,500rpm. However, in the case of the FCEA, the nitrogen oxide(NOx) were increased slightly, the carbon monoxide(CO) and particulate matter(PM) were decreased slightly when compared to that without the FCEA under all loads at an engine speed of 1,500rpm.
The area of greenhouse heating is 21,202 ha which becomes 42% among the total greenhouse area. As heating fuel, diesel or oil is usually used by 60%, and the heating cost takes 30 to 40% percentage at the greenhouse running. In this study, the pellet fuel heater was developed to replace oil for reducing the burden of greenhouse heating cost. The pellet fuel heater was composed of a conveying grate stoker, which could control temperature precisely like the diesel heater. Diesel and pellet were used for the greenhouse heating, whose calorific values are 9,200 and 3,898 kcal/kg, respectively. As the heating cost due to the saving effect of pellet fuel heater compared with diesel, greenhouse heating cost was reduced by 44% with pellet
In this study, the potential possibility of oxygenates on butyl ether(below BE) was investigated as an combustion activator for a direct injection diesel engine. It tested to estimate change of engine performance and exhaust emission characteristics for the diesel fuel and oxygenates additives blended fuel which has four kinds of blended ratio. The smoke of blended fuel(diesel fuel 80vol-%+BE 20vol-%) was reduced in comparison with diesel fuel, that is, it was reduced approximately 26%. And, power, torque and brake specific fuel consumption(BSFC) didn't have no large differences. But, NOx of BE blended fuel was increased compared with diesel fuel.
여러 가지 다른 형태의 노즐을 공기 선회식 버너와 공기의 선회가 없는 버너(CB-125 Burner)에 장치하여 공기 분사식으로 오일을 분사하여 연소로에서 연소시켰다. 연소로는 길이 3m에 약 1m 상(3) 의 연소공간을 가졌으며 상부에는 열전대를 장치하고 하부에는 물이 흐르는 관을 설치하여 열효율을 계산할 수 있게 설계하였다. 연소로 연돌부에는 CO 하(2), CO, O 하(2) 가스 분석기를 사용하여 과잉공기량과 고온계로 배기가스 온도를 측정하도록 하였다. 모든 측정치는 연소곡선과 효율곡선에 의하여 얻어진 상수를 이용하여 계산한 연소로 성능방정식에 의하여 평가하였다. 실험치에 의해 계산한 벽면 열손실량과 열전달 공식에 의해 산출한 열손실량을 비교 분석하여 측정치의 정확도를 추정하고 과잉공기의 효과도 검토하였다. 그 결과 본 연구에서 사용된 두 종류의 버너와 여러 형태의 노즐이 오일 연소시 열효율 면에서 큰 차이를 보이지 않고 있음을 알았다.
국산 소형어선용 예연소실식 디젤기관의 연료유를 가열할 경우, 연소특성 및 기관성능에 미치는 영향에 관하여 실험한 결과를 요약하면 다음과 같다. 1) 연료유 분사시작점은 연료유 가열온도의 증가에 따라 늦어지는 경향을 나타냈으며, 특히 저부하 운전시 늦어지는 경향이 현저했다. 2) 연소최고압력점은 연료유 가열온도의 증가에 따라 늦어졌으며, 연소최고압력은 연료유 가열온도 증가에 따라 감소하였으나 부하의 증가에 따라 증가하는 경향을 나타내었다. 3) 연료소비율은 부하의 증가에 따라 감소하였으며, 연료소비율이 가장 작은 연료유의 최적가열온도는 150℃부근임을 나타내고 있다. 4) 그을음농도는 부하와 연료유 가열온도의 증가에 따라 증가하는 경향을 나타냈다.