• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.138-143
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• 2006

Modification of injector, oil ring tension reduction and oil pump rotor re-matching with optimization of relevant engine control parameters could drive fuel consumption reduction of HSDI diesel engine. A 5 holes injector was replaced with a 6 holes with smaller nozzle hole diameter and 1.5 k factor, and evaluated in a view of fuel economy and emission trade-offs. With introducing smaller nozzle hole diameter injector, PM(Particulate Matter) was drastically decreased for low engine load and low engine rpm. Modification of oil pump and oil ring was to reduce mechanical friction and be proved to better fuel economy. Optimization of engine operating conditions was a great help for the low fuel consumption. Influence of the engine operating parameters· including pilot quantity, pilot interval, air mass and main injection timing on fuel economy, smoke and NOx has been evaluated with 14 points extracted from NEDC(New European Driving Cycle) cycle. The fuel consumption was proved to $7\%$ improvement on an engine bench and $3.7\%$ with a vehicle.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.13-25
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• 2007

Viscosity, adhesion and cohesion of asphalt binder are very important characteristics in asphalt pavement. However, these characteristics can cause some problems such as inaccurate amount of asphalt mixture, reduction of asphalt content and loss of workability during asphalt pavement construction. Asphalt release agent has been used to solve these problems. Diesel oil and vegetable oil are generally used as an asphalt release agent in Korea. However, these agents have been criticized from environmental and binder integrity reasons. Therefore, this study evaluated the characteristics of asphalt release agents including diesel oil, vegetable oil and two emulsion type oils. From the study, it was found that the diesel oil resolved the binder within ten minutes and vegetable oil stripped the binder from mixture within one hour after contacting with asphalt mixture. And also, from the test for estimating the application cycle of asphalt release agent, it appears that diesel oil and vegetable oil should be applied to construction equipments every time in their uses. However, diesel oil and vegetable oil showed a good performance as a lubricant for detaching the asphalt mixtures from the truck bed.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.191-193
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• 2000

To find out the countermeasure to plant damage at soil contaminated with oil, several adsorbents such as muck, peat, sawdust and PEAT SORB were treated at diesel oil contaminated soil. As the results, sawdust and PEAT SORB showed better effect of oil adsorption than muck and peat. Removal rate of diesel oil with sawdust treatment was higher than 95% at the condition which the ratio of adsorbent amount to oil was higher than 1:2(w/v). And the releasing amount of oil from adsorbent-oil complex was very small. With the oil treatment of $4,000\;L{\cdot}ha^{-1}$ at tillering stage, rice plant height and chlorophyll content were lower than control at non-adsorbent treatment, but those were increased at sawdust treatment.

• Journal of Soil and Groundwater Environment
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• v.22 no.1
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• pp.13-17
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• 2017

Over 30% of domestic soil contamination has occurred via petroleum products and complex oil. Moreover, contamination by complex oil is more intense than it is by a single petroleum product species. In this study, we analyzed sectional TPH (total petroleum hydrocarbon) pattern and sectional ratio of current domestically distributed petroleum products, such as kerosene, diesel, bunker C, and lubricant and complex oils, to determine pollution characteristics of the soil. In the TPH pattern, kerosene, which is a light distillate, had an early retention time, and lubricant oil, which is a heavy distillate, had a late retention time in the gas chromatogram. In addition, we obtained a complexly contaminated soil via diesel and lubricant oil from the Navy and inspected it for its ratio of complex oil species. The inspection results showed that this soil was contaminated with 85% diesel and 15% lubricant oil. The method developed in this study could be used to determine complex petroleum sources and ratios at sites with accidentally contaminated soil.

• Journal of ILASS-Korea
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• v.18 no.4
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• pp.182-187
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• 2013

This study was performed to investigate the effect of biodiesel derived from waste cooking oil on the spray behavior and macroscopic spray characteristics. To analyze quantitative characteristics of test fuels, injection quantity was measured at various injection pressures and the spray images of injected fuels in the pressurized chamber were obtained by using a high speed camera and image analysis system. Based on the measured spray images, the spray tip penetration and spray cone angle were investigated at various energizing timings and injection pressures. In this work, the experimental results showed that the injection quantity of waste cooking biodiesel indicated the higher quantities than diesel at high injection pressure. As the injection pressure was increased, the spray tip penetrations of biodiesel were higher value than diesel. The difference of penetration between biodiesel and conventional diesel fuel was reduced in accordance with the increase of injection pressure. Also, the spray angles of diesel were larger than that of biodiesel because diesel fuel has lower viscosity than biodiesel. In addition, the spray evolution processes of biodiesel fuel at various injection pressures and the elapsed time after the injection were compared to the conventional diesel fuel.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.105-113
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• 2014

Spray and combustion process with waste cooking oil (WCO) biodiesel and commercial diesel were analyzed in an optically-accessible single-cylinder compression ignition diesel engine equipped with a high pressure common-rail injection system. Direct imaging method was applied to investigate spray and combustion characteristics. From the mie-scattering results, it was verified that WCO biodiesel had a longer injection delay compared to diesel. Spray tip penetration length of WCO biodiesel was longer and spray angle was narrower than those of diesel due to poor atomization characteristics. In terms of combustion, WCO biodiesel showed later start of combustion, while flame was vanished more rapidly. Analysis of flame luminosity showed that WCO biodiesel combustion had lower intensity and lasted for shorter duration.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.6
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• pp.48-53
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• 1988

In a previous report, the properties of vegetable oils as diesel fuel substitutes were investigated and the basic load performance of a diesel engine was examined using vegetable oil. The results show that despite of the long term chain hydrocarbon structure and large droplet size due to high viscosity, vegetable oils have good basic performance and exhaust emissions, however they cause serious problems as carbon deposit buildup, they have poor durability, and also poor thermal efficiency. In this paper, the startability and engine durability with long term operation was tested by physical methods for reducing viscosity when vegetable oil was used as compared against diesel fuel. The results obtained in this investigation may be stated as follows; (1) There is no problem in startability when vegetable oil was used as diesel fuel substitutes as far as fuel temperature is higher than 30.deg. C (2) The carbon deposits were most extensive at lower loads and lower engine speeds, and deposit buildup more heavily on the cooler parts of the combustion chamber wall. (3) Blends with 25% diesel fuel and 20v-% ethanol are effective in reducing the carbon deposit buildups. (4) Significant improvement in carbon deposit and piston ring stick can be obtained by heating fuel(200.deg.).

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.11
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• pp.3054-3062
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• 1995

Recently, the improvement of fuel economy and the reduction of exhaust smoke and NOx have been successfully achieved by supplying diesel engines with emulsified diesel oil with water particles. In the present paper, the difference between the combustion of injected emulsified fuel and that of diesel oil spray is clarified by means of taking high-speed and color photographs of the flames in the engine cylinder. As the results, the two kinds of fuels show different combustion behavior each other in the growth of initial flame and in the termination of combustion process in the cylinder. Then, suitable combustion chamber design for the use of emulsified fuel is discussed on the basis of experimental data for various distribution of spray in different kinds of piston cavities. Some methods of clearing troubles caused by emulsified fuel injection are also discussed on the basis of performance tests with a remodeling test engine.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.5
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• pp.670-676
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• 2008

A diesel engine requires a high Performance of lubrication because of the extreme conditions such as high temperature and pressure during combustion process in a cylinder. Many researches to improve the lubrication performance on the extreme condition have been executed. The lubricant oil suspended with nano-metal particles is the one of the measure. In this study, the nano-lubricant oil is applied on a commercial diesel engine, and the engine performance is tested. The results show the increase of maximum torque and the decrease of cylinder pressure, exhaust gas temperature, CO emission.

• Journal of Advanced Marine Engineering and Technology
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• v.12 no.1
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• pp.28-36
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• 1988

Since the oil shocks of 1970s, the quality of the fuel oil for marine diesel engines has become more degarded than ever. When the poorer quality fuel is burned, carbon residues of the fuel oil cause blockage of the fuel injection valve nozzle and troubles of fuel injection system. The mis-firing of engine occurs due to the decrease of fuel quantity injected, the decrease of compression pressure in the slow speed range, the increase of fuel leaked and the high ignition temperature of degraded fuel etc. This paper is to investigate theoretically the effects of mis-firing on the crankshaft axial vibration of diesel engine. The cylinder pressure in operation is calculated by the computer aided simulation of closed cycle for a large two-stroke diesel engine and also the exciting force of axial vibration and the resonance amplitudes are calculated. And then, the condition of normal state, misfiring and one-cylinder cut-off operation are analyzed. The results of calculations show good agreements with those of the actual measurements.