• Journal of the korean Society of Automotive Engineers
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• 제12권4호
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• pp.35-46
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• 1990

The instantaneous friction in main bearings of a single cylinder diesel engine was determined by measuring the instantaneous angular velocity, calculating the resulting forces acting on the bearings, and solving the unsteady Reynolds equation in combination with the mobility method. The considered system consists of only the crankshaft with flywheel and oil pump. The thermal effects were not considered because of the short testing time. The tests were conducted using an electric start motor. The results indicated that when the bearing is not near equilibrium for very small speeds, simple film lubrication theories are not accurate. The details of grooves and unsteady terms in the Reynolds equation cannot be ignored for increasing efficiency of instantaneous friction calculation of the engine bearings. The effects of speed on instantaneous friction and energy lost in friction were determined.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.745-746
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• 2006

This lecture introduces new press, adapter and control concepts to size multi-level sintered components. The essential thing here is that the advantages of the multi-plate technology have been applied to the sizing adapter concept. Thus, the new concept meets the demands for a modern P/M manufacture and offers sufficient potential to size any future, complex sintered components such as synchronizer hubs, oil pump wheels and VCT parts with highest precision. Furthermore, it outlines a new flexible concept for the parts transfer, including feeding, orientation and lubrication while responding to the high demands on process stability and short change-over times.

• Journal of Drive and Control
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• 제14권1호
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• pp.29-34
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• 2017

This study analyzed a life test method for a power take-off (PTO) gearbox. An engine transfers mechanical power (rotation and torque) to a hydraulic pump through a PTO Gearbox with one input shaft and three output shafts. PTO gear box durability under high loads over long time periods was tested using dynamometers. In order to reflect the rated operating conditions, power must be distributed to each output shaft, and experiments were conducted under various conditions to verify the characteristics of the distributed power. An accelerated life test was designed using speed and torque as acceleration factors. Also, efficiency tests were conducted under various load conditions. Also, a lubrication oil composition analysis was performed to analyze gearbox wear status.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 한국윤활학회 1994년도 제20회 학술대회
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• pp.49-53
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• 1994

베인형 펌프, 모터 등의 마찰, 마모특성에 관해서 많은 연구가 있었으나, 베인펌프는 구조로부터의 제약이 많기 때문에, 대용량, 고압, 고속화라는 일련의 요구를 만족시키는 것이 쉽지 않아, 그 요구에 부응하기 위해 지금까지의 연구가 내마모성 작동유, 표면처리 기술, 특수 베인기구등의 개발을 제약에 부딪칠 때마다 필요에 따라 한결같이 경험적으로 이루어졌으며, 측정에 대한 면에서도 동적 조건 하에서의 측정은 거의 없으며, 해석에 관해서도 일반성이 상당히 결여된 상태라 할 수 있다. 따라서 본 연구에서는 유압 베인펌프의 베인과 캠링간의 접동 모델로써 동적 마찰 실험장치를 제작하여, 베인 선단의 마찰력을 측정하고 이를 기초로 하여 실기 유압 베인펌프의 베인과 켐링내면간의 접동부에 관한 마찰특성을 추정하는 것을 목적으로 하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제23권12호
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• pp.815-820
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• 2011

A scroll expander was designed for an energy converter from waste heat of IC engine coolant to useful shaft work. The scroll expander is to run in a Rankine cycle which receives heat energy transferred from engine coolant circulation cycle. The working fluid was Ethanol. For axial compliance, a back pressure chamber was provided on the rear side of the orbiting scroll. Lubrication oil was delivered by a positive displacement type oil pump driven by the shaft rotation. Performance analysis on the scroll expander showed that the expander efficiency was 63.4%. It extracts shaft power of 0.6 kW out of engine coolant waste heat of 17.5 kW, resulting in the Rankine cycle efficiency of 3.43%.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 한국윤활학회 2004년도 학술대회지
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• pp.255-260
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• 2004

Recently, the technologies related to the swash plate type oil hydraulic piston pump are requiring extreme technologies to overcome the limit of high efficiency in cope with high speed and pressure, and are devoted to compact the unit, to gain low noise level, and to adopt electronic technologies, and the question regarding to maximize the mechanical efficiency, that is, to minimize the torque loss by minimizing the leakage loss in the relative sliding region but these are in trade-off relation that tribological responding is very difficult. Cylinder block-valve pate in high speed relative sliding motion has the characteristics that should be extremely controlled for the optimization of these leakage loss and mechanical efficiency, and pressure resistance designing of them is important for high pressure performance. But, studies on the stress analysis of these parts have not been performed briskly, so in this paper the stress distribution and the region where the highest displacement appears are described through the static stress analysis using CATIA V5. Through the future studies on these theme, it has the purpose of finding the suitable materials for the other parts as well as cylinder block and valve plate, in cope with high pressure operation through the stress analysis with the most similar conditions for the practical operation.

• Tribology and Lubricants
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• 제33권2호
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• pp.37-44
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• 2017

A DE-side LBP tilting pad journal bearing of a 1-stage overhung heat-pump compressor in a propylene process exhibited abnormal high-temperature behavior. Its temperature had been relatively high at $78^{\circ}C$ from the beginning of operation. In 2014, after three years of operation, it increased suddenly and reached $103^{\circ}C$. Installing a varnish removal equipment and others managed to stabilize the temperature at $95^{\circ}C$. We undertook a troubleshooting approach for reviewing the comprehensive status and integrity of the temperature design of the bearing. We performed lubrication and heat-balance analysis, based on the design engineering data and documents supplied by the OEM. For the base design data of DE-side TPJB, evaluating the effects of key design variables on bearing metal temperature showed that firstly, increasing the bearing clearance and supply oil flow-rate, and next, changing the oil type, and finally, increasing the machined pad clearance and offset, are more effective in reducing the bearing metal temperature. Furthermore, a clarification meeting with the OEM revealed that an incorrect decision had been made to decrease the bearing clearance to eliminate the SSV harshness issue, while not maintaining a sufficient oil flow-rate. We conducted a detailed retrofit design analysis, wherein we increased the oil flow-rate and bearing clearance by decreasing the preload. We predicted that the bearing temperature would decrease to $63^{\circ}C$ from $75.7^{\circ}C$ even at the rerate condition. Finally, after installing and operating a retrofit replacement bearing in 2015, the bearing temperature stabilized at a low temperature of $65^{\circ}C$. Currently (January. 2017), two year later, the bearing metal temperature remains at $65^{\circ}C$. Therefore, we can conclude that the abnormal high-temperature behavior of the bearing has been resolved completely.

• Journal of the Korean Applied Science and Technology
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• 제35권4호
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• pp.985-994
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• 2018

Bio-heavy oil for power generation is a product made by mixing animal fat, vegetable oil and fatty acid methyl ester or its residues and is being used as steam heavy fuel(B-C) for power generation in Korea. However, if the fuel supply system of the fuel pump, the flow pump, the injector, etc., which is transferred to the boiler of the generator due to the composition of the raw material of the bio-heavy oi, causes abrasive wear, it can cause serious damage. Therefore, this study evaluates the fuel characteristics and lubricity properties of various raw materials of bio-heavy oil for power generation, and suggests fuel composition of biofuel for power generation to reduce frictional wear of generator. The average value of lubricity (HFRR abrasion) for bio-heavy oil feedstocks for power generation is $137{\mu}m$, and it varies from $60{\mu}m$ to $214{\mu}m$ depending on the raw materials. The order of lubricity is Oleo pitch> BD pitch> CNSL> Animal fat> RBDPO> PAO> Dark oil> Food waste oil. The average lubricity for the five bio-heavy oil samples is $151{\mu}m$ and the distribution is $101{\mu}m$ to $185{\mu}m$. The order of lubricity is Fuel 1> Fuel 3> Fuel 4> Fuel 2> Fuel 5. Bio-heavy oil samples (average $151{\mu}m$) show lower lubricity than heavy oil C ($128{\mu}m$). It is believed that bio-heavy oil for power generation is composed of fatty acid material, which is lower in paraffin and aromatics content than heavy oil(B-C) and has a low viscosity and high acid value, resulting in inhibition of the formation of lubricating film by acidic component. Therefore, in order to reduce friction and abrasion, it is expected to increase the lubrication of fuel when it contains more than 60% Oleo pitch and BD pitch as raw materials of bio-heavy oil for power generation.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.67-68
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• 2006

This study suggests a precision flow control system that enables fluid injection of a few grams at a time in a few ms time duration. The fluid injection system suggested here consists of a high pressure fluid pump, a 3 way 3 position directional control valve, an injector and an orifice. The orifice is located between the directional control valve and the injector. By supplying current signal to the directional control valve, the prescribed small amount of fluid can be supplied to a plant through the injector. The control robustness of the suggested system against the disturbances like the pressure change in a plant and the viscosity variation of the injected fluid is secured easily by using an orifice with very small inside diameter and setting the supply pressure with comparatively high value. The control performances of the suggested system are verified by numerical simulations and experiments. The outcomes of this research could be applied to the common rail injection control of lubrication oil for large size marine diesel engines, and other industrial plants.