http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
조명래,오대윤,한동철,Cho, Myung-Rae,Oh, Dae-Yoon,Han, Dong-Chul 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.11
The aim of this paper is to investigate the problem of strip down method, which is usually used to evaluate the engine friction level. The validity of strip down method was investigated by theoretical analysis of friction in crank and piston assembly. The friction of cylinder and piston assembly was analyzed under the various test conditions. The measured cylinder pressure was used as boundary conditions of friction torque and loss calculation. The friction loss of crank and piston assembly was influenced by test conditions that resulted from the variation of load condition. From the results, we have known that the strip down method could be possible to distort the friction loss of engine moving components.
조명례,김중수,오대윤,한동철,Cho, Myung-Rae,Kim, Joong-Soo,Oh, Dae-Yoon,Han, Dong-Chul 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.10
This paper reports on the effects of additional factors on the engine friction characteristics. The total friction loss of engine is composed of pumping and mechanical friction loss. The pumping loss was calculated from the cylinder pressure, and the mechanical friction loss was measured by strip-down method under the motoring condition. The various parameters were tested. The engine friction loss was much affected by oil and coolant temperature. The low viscosity oil was very effective to reduce the friction loss, and friction modifier was very useful to reduce the friction loss at lower engine speed. The engine friction loss was varied with engine running time because of surface roughness decreasing and oil degradation. To prevent oil-churning effect, it was very important to maintain the proper oil level. The presented results will be very useful to understand friction characteristics of engine.
조명래,하경표,김중수,오대윤,한동철,Cho, Myung-Rae,Ha, Kyoung-Pyo,Kim, Joong-Soo,Oh, Dae-Yoon,Han, Dong-Chul 대한기계학회 2003 大韓機械學會論文集A Vol.27 No.1
The aim of this paper is to investigate the friction characteristics of piston assembly, which composed of ring pack and piston skirt. The friction force of piston assembly was measured by using the movable liner in the single cylinder engine, and the various parameters were tested. The friction force was suddenly increased at the expansion stroke due to higher cylinder pressure. The viscous friction was dominant at the mid stroke, but the boundary friction was dominant at the top and bottom dead centers. Through the experiment, we could validate previous theoretical study, and confirm that th e radial clearance and ring tension were very effective to reduce friction loss of piston assembly.
하경표(Kyoung-Pyo Ha),오대윤(Dae Yoon Oh),김우태(Woo Tae Kim) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Aeration rate in engine oil is one of the most important data in the development of engine lubrication system. Several methods were reported to measure oil aeration, but none of them ca measure it in real time.<br/> Thus, a new oil aeration meter that can measure oil aeration in real time was developed in this study. The system measures density variation of engine oil with the increase of oil aeration. The density measurements were done in running fluid in order to measure oil aeration in real time. The measurement uncertainty of the present oil aeration meter is about 1%. The oil aeration meter is connected to the place of engine where oil filters attached to, thus present measurement system is very convenient to install and does not need modification of engine. The system is successfully applied to the tests with good accuracy and repeatability.
카본 디포짓 형성에 대한 가솔린 엔진 오일의 열화와 온도의 영향
민병순(Byung-Soon Min),김중수(Joong-Soo Kim),이두순(Doo-Soon Lee),오대윤(Dae-Yoon Oh),최재권(Jae-Kwon Choi) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.6_1
In order to establish a new temperature criterion to prevent the pistons from ring sticking due to deposit formation, bench test and engine test were performed. Bench test results show that oil oxidation is more effective to the deposit formation than oil nitration. The temperature increase accelerates deposit formation and deposit formation increase rapidly above 260℃. Especially, in case of degraded oil, the deposit formation increases so rapidly that ring sticking can occur. The effect of piston temperature on the deposit formation was confirmed by engine test.<br/>
[연료 및 윤활유부문] 엔진 이상 소음의 발생 원인 및 기구 파악
서성현(Seonghyeon Seo),강경필(Jyungphil Kang),김원규(Won-Kyu Kim),오대윤(Dae-Yoon Oh),최재권(Jae-Kwon Choi) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
An internal combustion engine is highly susceptible to mechanical noises. They originate from combustion and mechanical motion of engine components, and cannot be avoided with an engine at a normal operation. However,<br/> abnormal engine noises at a specific period can occur due to various reasons. Here in this study, four cases of<br/> undesirable engine noises were investigated. To identity the mechanisms of engine noises, accelerations and movements of interested engine components were measured using accelerometers and gap sensors, respectively. Through the analysis of these experimental data, mechanisms for each case were found and provide the solutions for the reduction of the noises.<br/>