• Asia-Pacific Journal of Business
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• v.13 no.2
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• pp.39-50
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• 2022

Purpose - The purpose of this study is to examine how Korea's macroeconomic factors, such as GDP, CPI, Export, Import, Unemployment rate and USD/KRW exchange rate, are affected by the oil price shocks. Design/methodology/approach - This study used monthly and quarterly time-series data of each variable for the period 1983 to 2022, consisting of two sub-periods, to employ Granger causality test and GARCH method in order to identify the role of the oil price movement in macroeconomic factors in Korea. Findings - Korea's currency rate to the US dollar is negatively correlated with the price change of crude oil while the GDP change is positively correlated with the price change of crude oil with strong relationship between Export and Import in particular. The exchange rate and GDP growth are believed to be not correlated with the oil price change for the pre-GFC period. According to the Granger causality test, the price change in crude oil has a causal impact on CPI, Export and Import while other factors are relatively slightly affected. Transmission effect from the oil price to Export is found and there also exists volatility spillover from oil price to economic variables under examination. Comparing two sub-periods, CPI and Export volatility responds negatively to shocks in the oil price for the pre-GFC period while volatility of CPI and Unemployment reacts positively to the oil price shocks for the post-GFC period. Research implications or Originality - The findings of this study could be helpful for both domestic and international investors to build their portfolio for the risk management since rising WTI price can be interpreted as a result of global economic growth and ensuing increase in the worldwide demand of the crude oil. Consequently, the national output is expected to increase and the currency is also expected to be strong in the long run.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.69-75
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• 2019

Oil seals have a great effect on transmission performance and durability. In this study, the optimal rubber mix was derived using dispersion analysis to obtain excellent oil-seal rubber properties. ANOVA was performed twice. The factors were polymers, carbon, magnesium oxide, and calcium hydroxide, which were used as four factors in ANOVA. The response factors were four items (hardness, tensile strength, elongation rate, and compression deformation) obtained through an experiment with a confidence level of 95%. In the first ANOVA, 168 tests were performed, and in the secondary ANOVA, 24 physical tests were conducted using polymers and carbon derived from the primary ANOVA. Through the ANOVA, we derived a rubber mixture recipe.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.204-208
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• 2003

This study presents a clutch-by-wire system for automotive which can be utilized on a vehicle with a manual transmission real time while the vehicle is in motion. The system consists of air valve, spring, oil pressure control valve, oil pressure cylinder, switch, etc. In this study, commercial vehicle was studied on improvement of no clutch pedal system. Therefore the results obtained effective driveability, gear shiftability, convenience for driver.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.224-228
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• 1988

Extensive development work which was carried out by Gold Star Cable Co., Ltd. has led to the optimal design, manufacture and test of fully engineered cable system for 345 kV self- contained oil filled (OF) underground cable. Details of design criteria and of tests are given. development of 345kV OF cable results in sucessful operations for ultra-high voltage power transmission requirement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3044-3050
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• 2015

The purpose of this study is to analyze the performance of the flow control oil pump for automatic transmission. The numerical model for analysis the performance of the flow control oil pump was develop and the characteristics of the internal flow, discharge flow rate, displacement of outer ring, driving torque, generation of cavitation was investigated according to rotating speed. As a result, the cavitation generation increased as the rotating speed increased. The volumetric efficiency was 90% for 2200 rpm and it decreased rapidly, then it decreased about 81% for 5000 rpm. Besides, the cavitation generation was 20%~30% for inlet of suction part, but it reduced below 13% owing to the compression. However, it shows higher cavitation generation for high rotating speed like 5000 rpm.

• Tribology and Lubricants
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• v.31 no.6
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• pp.281-286
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• 2015

Automotive transmission systems are assembled with a large number of gears and shafts, and rolling bearings are used to ensure their smooth operation. Gear oil in the gear box contains solid particles such as wear debris from contacting gears and metallic chips. This particle-enriched lubricating oil can cause premature failure of the rolling bearings. Research aimed at improving the service life of these rolling bearings has been confined mainly to design and lubrication of the inner/outer rings and the rolling elements. In this paper, we redesigned the shape of the cage pocket of a deep groove ball bearing to reduce the premature failure due to particle contamination. Test bearings are assembled with this new cage design containing a hole punched in the cage pocket. Endurance tests are carried out using the contaminated lubricating oil with miracle grid as hard particle. The duration and damaged bearing component shapes are compared for two different cages. The B₁₀ life of bearing with new cage is increased by about 66% compared to the conventional cage. This is because the hard particles can be easily discharged through the pocket hole without staying for a long time in the lubrication regions. This greatly decreases abrasive wear and dents on the highly stressed ball bearing surfaces. Therefore, the cage design of this study, containing a pocket hole, can significantly delay the premature failure of rolling bearings and improve the endurance life.

• Journal of Biosystems Engineering
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• v.40 no.2
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• pp.95-101
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• 2015

Purpose: During the start-up period, the response time of a hydraulic system increases in the winter because of the increased oil viscosity caused by the cold weather. The problems of delayed tractor starting and excessive wear of the clutch disk occur for these reasons. Therefore, this study develops an analysis model using the commercial hydraulic analysis program AMESim to examine the characteristics of delays in power shuttle starting at different oil temperatures. Methods: In the experiment, a tractor was stationary on a flat surface with the engine running at a constant speed of 1,080 rpm. The forward lever was then pressed to activate the power shuttle at three different oil temperatures, and the pressure changes were measured. The pressure on the forward clutch control valve was measured by a pressure gauge installed on the hydraulic line supplied to the transmission from the main valve. An analysis model was also developed and verified with actual tests. Results: The trend of the simulated pressures of the power shuttle is similar to that of the measured pressures, and a constant modulation period was observed in both the simulation and test results. However, the difference found between the simulation and test results was the initial pressure required to overcome the initial force of the clutch spring. Conclusions: This study also examines the characteristics of the delayed startup of the power shuttle at different oil temperatures through simulations.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.618-620
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• 1993

This system using optical fiber provides various information about underground tunnel and power transmission lines-atmospheric temperature, humidity, oil pressure, flammable gas, cable behavior, and so on. To transmit various data and to keep reliability, optical MUXs are adopted. User can easily operate monitoring software by using GUI.

• Korean Journal of Food Science and Technology
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• v.51 no.6
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• pp.531-536
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• 2019

In this study, the optimization of the manufacturing process for the oil-in-water emulsification of rice bran oil was performed by response surface methodology (RSM) using varying amounts of the emulsifier (0.05-0.25%), varying rotation speeds of the homomixer (4,000-8,000 rpm), and varying water to oil ratios (0.8-1.6%) as independent variables, and the emulsion stability index (ESI) as the dependent variable. The optimization conditions predicted by the RSM model were 0.2%g of the total amount of the rice bran oil emulsion, emulsified at the homomixer rotation speed of 6,700 rpm using a water to oil ratio of 1:3. The ESI of the rice bran oil emulsion prepared under the optimized conditions was 95.7%, which was similar to the predicted value of 94.4% obtained by the RSM model. The transmission stability and the backscattering values were found to agree with each other over time and the turbiscan stability index was less than 0.7, indicating that the aggregation and upper floatation were less while the dispersion stability was maintained.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.628-632
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• 2001

Experimental approach was investigated to improve gear rattle noise of a small car. During the development of a small car serious problem occurred inside the transmission gear units. The transmission was a carried over system from a less powered predecessor. Several components of suspicion were investigated, and applied to reduce rattle noise. In general, backlash, the assembly gaps, and the clutch disk rattle induce gear rattle noise. Above mentioned improvements were applied to reduce the noise, but still problem remained. Meanwhile, the temperature inside the gearbox was reported to be unusually high and the life of transmission oil quality deteriorated drastically, Temperature increment caused the large gap between the bearing outer diameter and the transmission housing. Large gap made the gear shaft assembly move intermittently and impact each other. The tighter control of the assembly gap allowed the rotating shafts smoothly and reduced the gear rattle noise even in the high temperature range.