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 recent years, our reality is facing a serious risk of air pollution from transport vehicles. In particular, various exhaust emissions from diesel engines are pointed out as a serious cause of environmental pollution. This study attempted to study the potential of biodiesel as an alternative energy for CRDI diesel engines. When biodiesel 30% was applied, the smoke emission was reduced by 40% at 4000rpm compared to diesel. On the other hand, there was no significant difference in output, torque, and energy consumption. However, NOx emissions tended to increase compared to diesel. The applicability of biodiesel to CRDI diesel engines has been demonstrated for the characteristics of output and smoke emissions.
선박용 디젤엔진의 NOx 환원제로 액체 우레아를 사용하는 SCR 기술이 널리 사용되고 있다. 하지만 액체 우레아 대신에 고체 상의 암모늄 카바메이트를 NOx 환원제로 사용하면 저온 NOx 저감율 및 암모니아 저장용량 측면 등에서 다양한 장점이 있다. 이에 따라 본 연구에서는 암모늄 카바메이트를 EA, FTIR, XRD 방법으로 분석하여 순도를 관리하는 방법을 제시하고자 하였으며, 다양한 온도와 압력 조건에 암모늄 카바메이트가 노출되었을 때의 물질 변화 특성을 고찰하고자 하였다. 본 연구를 통하여 암모늄 카바메이트의 순도를 EA 분석을 통해 효과적으로 관리 할 수 있음을 알 수 있었으며, 선박용 디젤엔진의 SCR 시스템에 적용될 것으로 예상되는 열분해 온도 조건에서 가열과 냉각을 반복한 암모늄 카바메이트에 대한 FTIR 분석결과, 물질 특성은 변화하지 않는 것을 확인하였다. 또한, 대기 중에 장기간 노출된 암모늄 카바메이트는 암모늄 카보네이트로 물질 변화함을 알 수 있었다.
In this study, the spray characteristics of blending fuel with diesel fuel and high viscosity biodiesel fuel was investigated. The research was performed for the effect on biodiesel fuel blending ratio and injection pressure for the spray behavior. The experimental process of spray injection was analyzed with LDPAlaser diffraction particle analyzer). In addition, spray atomization characteristics were researched with SMD(Sauter mean diameter) and droplet distribution on various injection pressure conditions. Fuel containing high viscosity biodiesel fuel has some different spray behaviors on account of the viscosity and surface tension. Though this experimental result, we found that the increase of injection pressure enables SMD to get smaller, but the increase of blending ratio makes SMD larger.
The potential for biodiesel to replace diesel has been explored as an alternative fuel for naturally aspirated indirect injection diesel engines. Overall biodiesel smoke emissions were significantly reduced compared to diesel fuel, which was approximately 36% lower at 2000 rpm, peak load conditions. And torque, power and brake energy consumption did not show much difference. However, compared to diesel fuel, NOx emissions from biodiesel have increased. To combat this problem, an EGR(exhaust gas recirculation) method has been applied to reduce NOx emissions. It was confirmed that simultaneous reduction of NOx and smoke was confirmed by cooling EGR method(10~15%) and biodiesel(20 vol%).
Biodiesel is a remarkable alternative fuel for the diesel engine among various countries. Various studies are carried out on the environmental and economic effects as well as the nature of diesel engine fuel biodiesel in the combustion process and emission characteristics. In this study, CRDI diesel engines used diesel fuel and 20 % biodiesel blend fuel (BD 20 %) as fuel, with City-mode exceeding 300 hours. Engine performance and emissions were sampled at one-hour intervals for analysis. The engine was inspected after testing to check the engine parts (valves and injectors). It was concluded that 300 hours of operation using BD 20 % does not cause abnormal deterioration of the engine or abnormal changes in engine power and exhaust gas.
The purposes of improving air pollution and suggesting energy resources have intensified research on various alternative energy for diesel combustion engines to solve severe environmental influences caused by air pollution. In this study, the applicable possibility of biodiesel and oxygenates (EGBE) was investigated as a cuspy method on decreasing the smoke emission. The smoke emission of blending fuel (biodiesel and EGBE) was reduced in comparison with commercial diesel fuel and it was reduced almost 63% at 2000 rpm, full load. But torque and brake specific energy fuel consumption rate didn't have any large changes. Also, the effectiveness of exhaust gas recirculation (EGR) for the reduction of NOx emission has been investigated. It was shown that simultaneous reduction of NOx and smoke emission was achieved with biodiesel(90%), oxygenates (10%) and cooled EGR rates (10%) in an IDI diesel engine.
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.
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 possibility of biodiesel fuel and oxygenated fuel(dimethoxy methane, DMM) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel (diesel fuel 90vol-% + DMM 10vol-%) was reduced approximately 70% at 2500rpm, full load in comparison with the diesel fuel. Engine power and brake specific energy consumption showed no significant differences. But, NOx emission of biodiesel fuel and DMM blended fuel increased compared with commercial diesel fuel due to the oxygen component in the fuel. It was needed a NOx reduction counter plan that EGR method was used as a countermeasure for NOx reduction. It was found that simultaneous reduction of smoke and NOx emission was achieved with diesel fuel (95 vol-%) and DMM (5 vol-%) blended fuel and cooled EGR method (15%).
This research aims to analyze the potential possibility of the butyl ether (BE, oxygenates of di-ether group) as a fuel additives for a naturally aspirated direct injection diesel engine fuel. Compared with the diesel fuel, smoke emission decreased approximately 26% by applying the blended fuel(diesel fuel 80 vol-% + BE 20vol-%) at the engine speed of 2,500 rpm and with full engine load. There was none significant difference between the blended fuel and the diesel fuel on the power, torque, and brake specific energy consumption rate of the diesel engine. But, NOx emission from the blended fuel was higher than that of the commercial diesel fuel. As a counter plan, the EGR method was employed to reduce the NOx. We found the possible area where the simultaneous reduction of the smoke and the NOx emission from the diesel engine was achieved by applying the BE blended fuel and the cooled EGR method.
Rolling contact fatigue(RCF) is a major cause of failure that appears in components of rolling contacts. In the recent years, the fatigue propagation and failure have been an important issue in respect of the safe operation and to reduce the noise and vibration of the rolling contact components. The water-contaminated lubrication is known to be one of the significant factors that reduces the lifetime of the rolling contact components. Thus, in this study, the effect of water-contaminated lubrication environment on the rolling contact fatigue was investigated. Bearing life testing was performed in two different lubrication conditions (i.e. normal lubrication environment and water-contaminated lubrication environment). The effect of the debirs on the rolling contact fatigue could be eliminated by establishing the debris filter system. Microscopic features of the rolling contact surfaces were examined using energy dispersive spectrometry and non-contact 3D measurement system. In the case of the water-contaminated lubrication, the increase of surface roughness values up to 17.6% was observed. The oxidation state and pattern of the rolling contact surfaces were very different depending on the lubrication environment. It was also found that the bearing rating life, , was decreased significantly in the watercontaminated lubrication condition. The amount of reduction was about 49.7%.
The purpose of the study was to simplify standard HACCP manual for improving the on-site applicability and increasing the implementation rate of HACCP program for small- and medium-sized dairy farms (SMDF). A survey was carried out in 32 SMDFs using a structured questionnaire. The results indicated that the number of workers had a positive correlation with HACCP certifications (p < 0.05). Most of HACCP non-certified farms (66.7%) were run by two workers with 40-60 cows and milking yields of 1,000-1,500 L per day. Major drawbacks for dairy farmers to implement current HACCP system were the difficulties in daily recording and facility management (40%). On the basis of the survey results, it was suggested that the development of on-site standard HACCP manual and user-friendly record chart with O/X checklist were the most urgent factors to increase HACCP implementation rate. In addition, the alternative third party service for microbial and chemical tests could also be accompanied for small-sized dairy farms.
두 종류의 Cronobacter 선택배지(DFI agar, R&F agar) 의 분유 및 건조호박 내 Cronobacter의 선택 분리능을 realtime PCR법과 함께 비교하였다. 분유에서의 Cronobacter 검출률은 세 가지 방법에서 유의적인 차이를 나타내지 않았으나(p < 0.05), 건조호박의 경우 R&F배지와 real-time PCR법이 DFI에서보다 유의적으로 높은 검출률을 보였다 (p < 0.05). 배지 간 선택성에 있어서도, R&F 선택배지는 건조호박에서 DFI에 비해 유의적으로 높은 선택성을 나타냈다(p < 0.05). Real-time PCR 및 R&F배지의 사용은 분유뿐만 아니라, 건조 호박 등의 높은 경쟁세균총을 갖는 영유아식의 원료로 사용될 수 있는 식품군에서도 Cronobacter를 효과적으로 검출할 수 있는 방법으로 사료된다.
Membrane distillation (MD) is a hydrid membrane process using the temperature difference as a driving force. In order to enhance the performance (flux) of the MD process, various membrane structures (asymmetric or bi-composite) and materials (PP, PVDF or PTFE) have been suggested. In this study, the support layer of the commercial PTFE/PP bi-composite membrane is modifed by forming the macro punctures in it. The size and location of macro punctures were varied according to the designed support layer porosities (50, 60, 70 and 80 %). The modified membrane test was conducted by using the DCMD configuration. The flux of a modified membranewas enhanced up to 27 % compared with that of pristine membrane when the size of the macro puncture and overall porosity of the support layer were larger than 20 mm2 and 60 %, respectively.
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.
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.
Biodiesel is an alternative fuel of petroleum and has an effect on reducing smoke because that contains oxygen itself. This study shows the results on the durability of diesel engine with 4% biodiesel and WDP 1% as an alternative fuel during 110 hours. Engine dynamometer testing was complete at regularly scheduled intervals to monitor the engine performance an exhaust emissions. Through this experimental result, there was no clogging of the nozzle tip, and there was not carbon deposit on the injector tip. And, there was no unusual deterioration of the engine, or any unusual change in exhaust emission from using the blending fuel.
There are many pollutants emitted into the air. Some of these pollutants have a malodor. Unlike other pollutants, people are able to detect and feel discomfort when this type of pollutant becomes high peak concentration instantaneously. In this sense, the peak concentration has an important meaning in the odor management and modeling. In previous odor modeling, the peak concentration was calculated by correcting the one-hour average concentration using the correlation equation. This study was carried out to find appropriate method to predict the peak concentration using meteorological input data of high time resolution in the odor modeling. It show that the peak concentration could be directly calculated from the dispersion modeling without using the correction equation when fine time scales such as 1 min or less time intervals are used as the meteorological input.
In this study, the potential possibility of biodiesel fuel was investigated as an alternative fuel for a naturally aspirated common rail diesel engine. The smoke emission of biodiesel fuel 30 vol%(max. content) was reduced in comparison with diesel fuel, that is, it was reduced approximately 60% at 4000rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel.