• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.745-752
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• 2012

Diesel engines are most suitable for biodiesel fuel because diesel fuel has a higher cetane number compared to gasoline and diesel engines have no spark ignition system; hence, engine conversion is easy and cost effective. For these reasons, in this study, the spray behavior characteristics of vegetable palm oil were analyzed by using a common-rail injection system of a commercial diesel engine, and the results were compared with those obtained for the diesel fuel. The injection pressures and blend ratios of palm oil and diesel fuel (BD3, BD5, BD20, BD30, BD50, and BD100) were the main parameters. The experiments were conducted for different injection pressures-500 bar, 1000 bar, 1500 bar, and 1600 bar-by setting the injection duration at $500{\mu}s$. We determined there is no significant difference in the macro characteristics of the spray behavior (spray penetration and spray angle) in response to any change in the blend ratio of palm oil and diesel fuel at a fixed injection pressure. In particular, all experiments showed a spray angle of approximately $15^{\circ}$.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.442-448
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• 2012

The effects of zeolite-type catalysts addition on the thermal decomposition of the PP resin have been studied in a thermal analyzer, a Pyrolyser GC-mass, and a small batch reactor. The zeolite type catalysts tested were natural zeolite, used FCC catalyst, and ZSM-5. As the results of TGA experiments, the pyrolysis starting temperature for PP varied in the range of $330{\sim}360^{\circ}C$ according to the heating rate. Addition of the zeolite type catalysts in the PP resin increased the pyrolysis rate in the order of used FCC catalyst> natural zeolite> ZSM-5 > PP resin. Adding the used FCC catalyst in the PP reduced most effectively the pyrolysis finishing temperature. In the PY-G.C. mass experiments, addition of zeolite type catalysts decreased the molecular weight of pyrolyzed product. In the batch system experiments, the mixing of used FCC catalyst enhanced best the initial yield of fuel oil, but the final yield of fuel oil was 2% higher in the case of mixing of natural zeolite. Also in the carbon number analysis, used FCC catalyst was the most useful one in this experiments for fuel oil.

• Tribology and Lubricants
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• v.20 no.2
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• pp.84-90
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• 2004

It is very important to improve the durability and reliability of crankshaft because of conflicting demands for lower fuel consumption and higher power output. In this study, for the crankshaft bearing design, analyses were conducted to determine the lubrication characteristics such as oil flow rate, minimum oil film thickness, friction force and increase of oil temperature at main bearing and connecting rod bearing. Additionally, supplied oil pressure and temperature effects on the bearings were simulated to figure out lubrication characteristics on the bearings. Finally the effects of increasing the bearing width and clearance were introduced on the lubrication characteristics.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.81-88
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• 1999

In order to understand the relationship between the phase angle of piston ring and oil consumption was measured by analyzing $CO_2$concentration in exhaust gas. The use of hydrogen fuel not gasoline makes this possible because all of the carbon component in exhaust gas can be assumed to be produced from oil. As a result of experiment, it is known that the oil consumption varies periodically and a specific location of ring end gap was found at each peak of oil consumption. Therefore, it was found that the oil consumption was not constant even at the same operating conditions and this is because the relative locations of top and 2'nd ring end gap change arbitrarily.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.43-65
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• 2023

Recently, with the increasing international interest on environmental issues, efforts have been made to reduce greenhouse gas emissions due to ship fuel, however, the dependence on fossil fuel is expected to continue for a while. Since fuel costs account for a high portion of the total operating cost of a ship, it is necessary to analyze the influence of oil prices on the shipping markets. The purpose of this study is to evaluate the relationship between the international oil prices and the four major shipping markets for bulk carriers. This study employed WTI as the oil price variable while monthly data from 2017 to 2020 from the four major shipping markets by classifying freight rates, charter rates, newbuilding prices, and secondhand prices were also considered in multiple ship sizes of capesize, panamax, supramax, and handysize. Firstly, the results of the correlation analysis using the VAR model indicate that changes in international oil prices have a statistically positive (+) significant effect on BCIS only in the second time lag, on BSIS at all lags, and on BHIS only in the first staggered period. Secondly, as a result of correlation analysis using the VECM model, in the case of BPIC, BHIC, BCIN, and BHIR, the cointegration coefficient value has a negative (-) significant effect at the 5% significance level in the cointegration relationship with international oil prices. Further, in the case of the dynamic correlation, the increase in oil price in the first period of the lag leads to a decrease in the BCIN newbuilding prices while the increase in the oil price in the first and second period in the lag leads to a decrease in the BHIR used ship prices.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.547-554
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• 2018

Torrefaction is the promising process of pretreating biomass materials to increase the quality of their energy, especially to upgrade the materials' grindability so that it is suitable for a commercial pulverizer machine. In this study, torrefaction of oak, bamboo, oil palm trunk, and rice husk was carried out under different torrefaction temperatures ($300^{\circ}C$, $330^{\circ}C$, and $350^{\circ}C$) and different torrefaction residence times (30, 45, and 60 minutes). Complete characterization of the torrefied biomass, including proximate analysis, calorific value, thermogravimetric analysis, mass yield, energy yield, and grindability properties (Hardgrove Grindability Index) was carried out. Increasing the torrefaction temperature and residence time significantly improved the calorific value, energy density (by reducing the product mass), and grindability of the product. Furthermore, for commercial purposes, the torrefaction conditions that produced the desired grindability properties of the torrefied product were $330^{\circ}C-30minutes$ and $300^{\circ}-45minutes$, and the latter condition produced a higher energy yield for bamboo, oil palm trunk, and rice husk; however, torrefaction of oak did not achieve the targeted grindability property values.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.133-137
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• 2007

An experimental study is conducted to evaluate and compare the use of BiodieseDI Fuel supplements at blend ratio of 10/90(BDF10) and 20/80(BDF20), in four stroke, direct injection diesel engine located at the authors' laboratory. especially this Biodiesel is produced from Rape oil at the authors' laboratory. The tests are conducted using each of the above fuel blends, in the engine working at a speed of 1800rpm and at a various loads. In each test, specific fuel consumption, exhaust emissions such as nitrogen oxides(NOx), carbon monoxide(CO) and Soot are measured. The results of investigation at various operating conditions are as follows (1) Specific fuel consumption is increased average 1.52%, maximum 1.84% at load 25% in case of BDF10, and average 1.98%, maximum 2.80% at load 25% in case of BDF20. (2) CO emission is decreased average 5.14%, maximum 6.09% at load 0% in case of BDF10, and average 7.75%, maximum 9.13% at load 0% in case of BDF 20. (3) NOx emission is increased average 2.97%, maximum 3.74% at load 0% in case of BDF10, and average 3.84%, maximum 4.67% at load 0% in case of BDF20. (4) Soot emission is decreased average 9.36%, maximum 10.85% at load 75% in case of BDF10, and average 11.99%, maximum 13.95% at load 75% in case of BDF20.

• Environmental and Resource Economics Review
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• v.26 no.2
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• pp.257-286
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• 2017

This paper estimates the effects of imaginary repeated increases in excise duties on fuel oil consumption and on their income redistribution according to changes in consumer price index, if the inflation indexation system was introduced right after the second Energy Tax Reform ended in July, 2007 in Korea. In fact, nominal excise rates have not been adjusted since 2007. As a result, the real excise rates on fuel oils have been diminished inversely proportional to the consumer price index. Own- and cross-price elasticities of fuel oils such as gasoline and diesel oil are estimated under the general equilibrium framework based on the linear expenditure system. Counterfactual analyses through microsimulation in a static model are adopted to estimate the effects of introducing inflation indexation into the fuel tax in 2007 when the second Energy Tax reform ended on the fuel consumption and income redistribution in 2014. Microsimulations suggest that its introduction could have reduced the consumption of gasoline and diesel oil by 8.8% and 5.4%, respectively, ending up with increased excise revenue by 11.9%. The revenue increase in spite of decreased consumption is mainly because their demands are price inelastic. It could also have increased positive income redistributive effect by 0.01%p (from 0.12% to 0.13%), which is measured in terms of percentage decrease in Gini coefficient. In other words, the fuel excise on the two fuel oils decreased by 0.13% the Gini coefficient of before and after fuel tax income in 2014. This implies that the inflation indexation could have enlarged the income redistributive effect up to 0.13% in 2014, if it is introduced in 2007.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.2
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• pp.246-262
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• 2013

With increases in international oil prices, the proportion of fuel cost to the operational costs of a ship is currently increasing. To reduce fuel cost, a method for determining an economical route for a ship based on the acquisition of the sea state and the estimation of fuel consumption is proposed. The proposed method consists of three items. The first item is to acquire the sea state information in real time. The second item is to estimate the fuel consumption of a ship according to the sea state. The last item is to find an economical route for minimal fuel consumption based on the previous two items. To evaluate the applicability of the proposed method, it was applied to routing problems in various ocean areas. The result shows that the proposed method can yield economical ship routes that minimize fuel consumption. The results of this study can contribute to energy savings for environmentally friendly ships.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.1
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• pp.77-84
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• 1994

The oil crises in 1973 and 1978 stimulated the alternative fuel research activities in many countries around the world. Among the alternative fuels, methanol is one of the highest potential fuels for transportation. Methanol has been considered for use as automotive fuel, but it has a defect of the great latent vaporization heat. Therefore, authors have made the fuel vaporizing device in order to eliminate the fuel film flow heating the mixture. This paper presents a study on the characteristics of vaporization, engine performance, and emission which result from using the fuel vaporizing device.