• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.536-540
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• 2018

As the performance of engines improves, the temperature of engines is increasing, resulting in a high piston temperature. An excessively high piston temperature may result in torque drop or engine failure. An oil jet is used to reduce the piston temperature. In this study, to monitor the effect of oil jet, a templug was used to measure the piston temperature. A templug is a kind of sensor and the hardness of the templug changes according to the piston temperature. Using a templug, the maximum temperature of the piston was measured with and without an oil jet. The piston temperature was lowered using the oil jet. The highest temperature region changed from the center crown to the front/rear area. In addition, the temperature difference between the highest and lowest regions became smaller.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.604-608
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• 2015

In this paper, we study the characteristics of heat transfer for an insulated multi-core tube using glass wool as an insulator for the multi-core tube. By performing experiments and modeling, we examine the variations in the temperature characteristics of hydraulic oil inside the multi-core tube with atmosphere temperature, inlet temperature, and the flow rate of hydraulic oil for the insulated multi-core tube that we developed. When the minimum inlet flow rate of hydraulic oil employed within the scope of the research is 0.29 l/min, the temperature difference obtained in the experiments and numerical analysis was a maximum of $3^{\circ}C$. For a constant atmospheric temperature, as the inlet temperature of the hydraulic oil increases, the outlet temperature of the hydraulic oil will also increase, regardless of its inlet flow rate. Further, when the inlet flow rate of the hydraulic oil is more than 1.01 l/min, the effect of the atmospheric temperature on the temperature drop of the hydraulic oil is low.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.144-147
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• 2013

Sweating, which is the excretion of oil on the surface of a solid product containing several kinds of pigments in oil and is also solidified with wax, is a unique phenomenon often observed on the surface of cover make-up or lipstick. The cause of sweating is an imbalanced formula. Many studies have been conducted to decrease the symptoms of sweating in the field of cosmetics. Differential scanning calorimetry (DSC) is a thermo-analytical technique that measures the amount of heat required to increase the temperature of a sample as a function of temperature or time under certain conditions. DSC has been used to determine the thermal properties of oil/wax structures. This study investigates how the thermal characteristics correlate with the sweating symptoms. An oil/wax formulation with an optimal melting point was studied in an attempt to make a stable product by considering the thermal properties that represent minimal structural changes with temperature variation. In addition, the sweating of the oil/wax formulation was observed over a various temperature range. As a result, it was found that sweating was minimized when the structure remained static or little bit changed over a variety of temperatures.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.62-67
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• 2003

In this Paper, the dynamic temperature sensitivity and mu. temperature measurement errors of oil and air sensor in oil cooler are evaluated to predict design validity of sensors under special oil and atmosphere temperature changes. The temperature tracking of oil sensors for periodic temperature changes is simulated by obtaining thermal response coefficient from experiment. By this method, it is possible to design the optimal sensors with the admitted temperature measurement errors.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.495-503
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• 2017

Wax components can be precipitated when surrounding temperature decreases below wax precipitation temperature (WAT). WAT as well as pour point are important characteristics to evaluate the behavior of waxy oils. In this study, qualitative and quantitative evaluations of waxes in waxy model oils were presented after determining WAT and pour point. In case of anhydrous waxy model oils, ASTM D2500 may be most useful to determine WAT because of the transparent nature of model oils. With same apparatus, ASTM D97 is also applicable to determine the pour point of waxy oils in a serial determination. In case of emulsified model oils, however, it is difficult to measure WAT because of its opaque nature. This study employed FTIR spectroscopy to determine wax precipitation temperature and discussed the effect of emulsion state regarding the values of WAT. Further study would be needed to conclude the effect of water contents to WAT values in case of emulsified waxy oil.

• Journal of the korean Society of Automotive Engineers
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• v.17 no.3
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• pp.11-18
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• 1995

본 논문에서는 주철 라이너를 삽입한 알루미늄 블럭 엔진 개발과정에서 주조 불량이 발생하였을때, 냉각계에 일어나는 제반 현상을 분석하고, 이를 해결해 나가는 과정을 기술하였다. 이를 위하여 주철 블럭과 알루미늄 블럭을 장착한 엔진의 피스톤 온도와 블럭의 열유속, 열정산을 측정하였다. 측정한 결과는 다음과 같다. 1. 알루미늄 블럭 제작시 주철 라이너와 알루미늄 블럭 사이에 공기층이 크거나, 용탕 충진이 불완전한 주조 불량이 발생하면 열접촉 저항이 커져 엔진 열전달 경로에 큰 영향을 준다. 2. 알루미늄 블럭 제작시 주조 불량이 발생하면 피스톤에서 라이너로의 전열량이 줄어듦에 따라 냉각수로의 전열량은 감소하는데, 6,000rpm, 전부하에서 알루미늄 블럭의 출력 대비 냉각수로의 방열량의 비는 38.3%이고, 주철 블럭은 44.1%이다. 3. 알루미늄 블럭 제작시 주조 불량이 발생하면, 피스톤 온도가 15-20.deg.C 정도 상승하여 피스톤 손상을 유발시킬 수 있다. 4. 알루미늄 블럭의 주조가 완벽하게 되어 주철 라이너와 알루미늄 몸체 사이에서의 열접촉저항이 없어지면, 스토로크 방향에 따른 금속면 온도 분포가 균일하게 된다. 5. 실린더 라이너의 주조상태 개선없이 오일젯을 사용한 결과 피스톤의 온도를 만족할 만한 수준으로 감소시켰다. 6. 6000rpm, 전부하에서 오일젯 적용시 출력 대비 냉각수로의 방열량의 비가 38.3%에서 36.2%로 감소하고, 출력대비 오일로의 방열량의 비는 9.6%에서 11.2%로 증가한다. 7. 오일젯 작용시 오일 펌프의 용량 증대와 오일 쿨러의 장착이 필수적이다.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.1-8
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• 2015

Wax deposition hinders oil flow assurance. Huge amount of money and time were required for mitigation of wax deposition in the oil field. For prediction and mitigation of wax deposition problem, Wax Appearance Temperature(WAT), which is the temperature at which the first wax crystals start to form, needs to be measured in advance. There is a standard method which is optical way to measure the WAT of transparent oil. However, standard method cannot be applied to opaque oil which is common produced oil in the field. In this study, WAT of three transparent oil samples were measured using heat flux variation analysis, viscosity variation analysis and density variation analysis, and compared with WAT measured by standard method. As a result, WAT measured by density variation analysis is the more reliable than heat flux variation analysis and viscosity variation analysis. WAT of two opaque oils were measured using density variation analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.9-15
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• 2018

The turbochargers, which are used widely in diesel and gasoline engines, are an effective device to reduce fuel consumption and emissions. On the other hand, turbo-lag is one of the main problems of a turbocharger. Bearing friction losses is a major cause of turbo lag and is particularly intense in the lower speed range of the engine. Current turbochargers are mostly equipped with floating bearings: two journal bearings and one thrust bearing. This study focused on the bearing friction at the lower speed range and the experimental equipment was established with a drive-motor, load-cell, magnetic coupling, and oil control system. Finally, the friction losses of turbochargers were measured considering the influence of the rotating speed from 30,000rpm to 90,000rpm, oil temperature from $50^{\circ}C$ to $100^{\circ}C$, and oil supply pressure of 3bar and 4bar. The friction power losses were increased exponentially to 1.6 when the turbocharger speed was increased. Friction torques decreased with increasing oil temperature and increased with increasing oil pressure. Therefore, the oil temperature and pressure must be maintained at appropriate levels.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.23-24
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• 2020

커피박을 FeCl₃·6H₂O로 전처리하여 제조한 자성 복합재의 유출유 회수 실험을 진행하였다. 전반적으로 사용하지 않은 디젤엔진 오일이 사용한 디젤엔진 오일보다도 오일 회수율이 높게 나타났고, 수중온도가 5℃일때보다도 25℃일 때 오일 회수량이 더 높게 나타났다. 실험 결과는 모든 온도에서 오일 회수량을 높이기 위해서는 FeCl₃·6H₂O 전처리 용액의 농도가 최소한 0.1 M은 되어야 함을 보여 주었다.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.1-8
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• 2016

When the oil is produced in the low temperature environment, wax can be accumulated in petroleum production system(pipeline, riser) and causes problems such as pipeline stucking, disturbance of the oil production. These problems can be lead to time-consuming and economic losses for flow assurance. For prediction and mitigation of wax deposition, it is necessary to measure the Wax Appearance Temperature(WAT) which is a temperature when the wax crystals start to be formed. WAT standard measurement method of transparent oil has to determine the cloud point of sample to the naked eye and cannot be applied to continuous change of the temperature. In this study, wax behavior of transparent oil samples are recorded depending on temperature using Visualized WAT Measurement System. Also, WATs of transparent oil samples are measured by image processing and compared with the result of the standard method.