• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.187-190
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• 2012

An experimental study was performed to provide the effect of PM reduction and the improvement of diesel alternative ratio utilizing diesel-natural gas dual-fuel combustion mode in a retrofit 3.4-liter diesel engine. In order to achieve the same power as the original diesel engine, engine control unit (ECU) of the dual-fuel engine was calibrated. As a result, diesel alternative ratio was found that the maximum value of diesel alternative ratio was about 96%. Finally PM emission experiment was performed in C1-8 mode cycle and it was shown PM emission was extremely reduced down to $7.42{\ast}10^{-7}g/kWh$ comparing with mechanical diesel engine.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.8
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• pp.813-820
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• 2015

Straight vegetable oil (SVO) is widely recommended as fuel for diesel engines in general and especially for marine diesel engines. However, SVOs used directly as fuel for diesel engines may cause problems for the engines; SVOs blended with diesel oil are a better choice. To widen understanding of the possibility of using blended SVOs as fuel alternatives, this paper presents results of experimental research on the combustion of blended straight vegetable oil in a marine diesel engine's cylinders. Results show that the fuel combustion process have the same curves as in simulations and, in the case of using blended fuels with up to 20% palm oil, the test diesel engine technical parameters such as engine output, exhaust gas temperatures, and specific fuel consumption are very similar to those of diesel oil (DO). Based on these results, marine diesel engines are strong potential applications and particularly recommended for the use of SVO blends.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.607-613
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• 2001

The biodegradation rates of diesel oil by a selected diesel-degrading bacterium, Pseudomonas stutzeri strain Y2G1, and microbial consortia composed of combinations of 5 selected diesel-degrading bacterial were determined in liquid and soil systems. The diesel degradation rate by strain Y2G1 linearly increased $(R^2=0.98)$ as the diesel concentration increased up to 12%, and a degradation rate as high as 5.64 g/l/day was obtained. The diesel degradation by strain Y2G1 was significantly affected by several environmental factors, and the optimal conditions for pH, temperature, and moisture content were at pH8, $25^{\circ}C$, and 10%, respectively. In the batch soil microcosm tests, inoculation, especially in the form of a consortium, and the addition of nutrients both significantly enhanced the diesel degradation by a factor of 1.5 and 4, respectively. Aeration of the soil columns effectively accelerated the diesel degradation, and the initial degradation rate was obviously stimulated with the addition of inorganic nutrients. Based on these results, it was concluded that the major rate-limiting factors in the tested diesel-contaminated soil were the presence of inorganic nutrients, oxygen, and diesel-degrading microorganisms. To resolve these limiting parameters, bioremediation strategies were specifically designed for the tested soil, and the successful mitigation of the limiting parameters resulted in an enhancement of the bioremediation efficiency by a factor of 11.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.42-49
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• 2006

In this research. the diesel cycle was thermodynamically interpreted to evaluate the possibility of high efficiency by converting diesel engines to the high expansion diesel cycle, and general cycle features were analyzed after comparing these two cycles. Based on these analyses. an experimental single cylinder a long stroke with high expansion-diesel engine. of which S/B ratio was more than 3, was manufactured. After evaluating the base engine through basic experiments, a diesel engine was converted into the high expansion diesel engine by establish VCR device and VVT system Accordingly, the high expansion diesel cycle can be implemented when the quantity of intake air is compensated by supercharge and the effective compression ratio is maintained at its initial level through the reduction of the clearance volume. In this case, heat efficiency increased by $5.0\%$ at the same expansion-compression ratio when the apparent compression ratio was 20 and the fuel cut off ratio was 2. As explained above, when the atkinson cycle was used for diesel cycle, heat efficiency was improved. In order to realize high expansion through retarding the intake value closing time, the engine needs to be equipped with variable valve timing equipment, variable compression ratio equipment and supercharged pressure equipment. Then a high expansion diesel cycle engine is realized.

• Journal of Soil and Groundwater Environment
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• v.20 no.4
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• pp.15-21
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• 2015

Anaerobic biodegradation of diesel with coexisting heavy metals (Pb) was monitored in batch mode. Two different groups of the indigenous bacteria from a site contaminated with diesel and lead were used in this research: the first group was composed of a single species and the second group was composed of several species. The effect of heavy metals on the microbial population was monitored and confirmed the biodegradation mechanism in each combined contaminant. Growth of the microorganisms in 21 days was observed Diesel > Diesel + Pb > Diesel + Cu > Diesel + Pb + Cu > Diesel + Cr > Diesel + Pb + Cr. Indigenous microorganisms showed the adaptation in the Pb contaminate. Interactive toxic effect using AMES test observed larger synergistic effect than antagonistic in Diesel + Cr and Diesel + Pb + Cr. Therefore, the main effects of diesel biodegradation in the present of heavy metals are likely to exist other factors as well as toxic of heavy metals. This is a necessary part of the future studies.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.134-139
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• 2008

This research investigated variations of the engine performance and the exhaust emission characteristic of a direct injection diesel engine by fueling a commercial diesel fuel, which was blended with the di-ether group (butyl-ether: BE). The smoke emission reduced to 26% from the diesel engine with the blending fuel (diesel fuel 80 vol-% + BE 20 vol-%)at the full engine load of 2500 rpm compared to it with the diesel fuel only. The power, torque and brake specific energy consumption of the diesel engine showed very slight differences. The NOx emission from the diesel engine, however, with the blended fuel was higher than with the commercial diesel fuel only. By applying EGR method, as a counter plan of the NOx reduction, this research obtained reductions of the smoke and NOx emission at the same time from the diesel engine with the BE blended diesel fuel.

• Tribology and Lubricants
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• v.16 no.5
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• pp.332-340
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• 2000

The reduction of sulfur content in the diesel fuel has caused the poor lubricity of diesel fuel in the distributor type injection pumps of diesel engines that use the diesel for lubrication of their moving parts. To investigate the reason for poor lubricity of low sulfur diesel fuels, the wear scar diameters by HFRR (High Frequency Reciprocating Rig) were measured on the diesel fuels from Korean markets and the results were compared with their physical and chemical properties. Also, the lubricity change and the improvement effects on lubricity additives for the ultra low sulfur diesel fuel, were made experimentally, that will be regulated to a maximum of 0.005 wt% from about 2005 were evaluated. As a result, a good correlation was found between the wear scar diameter and the polyaromatic compound which includes heterocyclic compound in the diesel fuel. It was also found that the content of polyaromatic compound including heterocyclic compound was affected by the amount of desulfurization treatment fraction. And the lubricity additives with ester base were more effective than that with acid base on the ultra low sulfur diesel fuel. Therefore, it is suggested that the factors affecting the lubricity stated above should be taken into account to improve the lubricity property of the diesel fuel in the refining process.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.51-56
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• 2009

Recently, lots of researchers have been attracted to develop various alternative fuels in diesel engine. The use of biodiesel fuel(BDF) is an effective way of substituting diesel fuel in the long run. But biodiesel fuel can affect the performance and emissions in diesel engine because it has different chemical and physical properties from diesel fuel. In this study, to investigate the combustion characteristics of biodiesel fuel as an alternative fuel for D.I. diesel engine, experiments were carried out at the three-cylinder, four stroke D.I. diesel engine with T/C. As a result, shorter ignition delays were observed for the biodiesel blend cases relative to the diesel oil. The pick value of premixed combustion for the rate of heat release is increased with decreasing C.F.W. temperature.

• Journal of Biosystems Engineering
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• v.34 no.3
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• pp.135-139
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• 2009

Harmful exhaust emissions of diesel engines are recognized as main causes of air pollution in these days. But, the direct injection diesel engine is widely used for sake of minimization on energy consumption. Because biodiesel fuel is a renewable and alternative fuel for a diesel engine, its usability is expanded. To investigate the effect of biodiesel fuel(extracted from rapeseed oil) on the characteristics of performance and exhaust emissions in an agricultural diesel engine, the biodiesel fuel derived from rapeseed oil was applied in this study. Smoke emission of esterified rapeseed oil was reduced remarkably by approximately 44.5% at 1500 rpm, full load in comparison with the commercial diesel fuel. The power, torque and brake specific energy consumption of the diesel engine showed very slight differences. It was concluded that esterified rapeseed oil could be utilized effectively as an alternative and renewable fuel for agricultural direct injection diesel engines.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.1
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• pp.77-82
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• 1999

This study was conducted on the properties of exhaust emissions of diesel oil and fish oil blended with diesel oils using a direct injection diesel engine at different loads, and on the conditions of carbon deposits of diesel oil and 40% blend oil in the combustion chamber after 20 hours operation at $\frac{1]{2}$ load. The properties of exhaust emissions by fish oil blended with diesel oils showed no significant difference with diesel oil. However, soot emissions decreased, increasing the ratio of fish oil. Carbon deposits by fish oil blended with diesel oils were high level compared with diesel oil, which might be overcome by preheating of fuel oil and operating conditions.