비고정식 피스톤 핀의 회전운동에 관한 연구

전상명,Chun, Sang-Myung 한국트라이볼로지학회 2007 한국윤활학회지(윤활학회지) Vol.23 No.3

In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. Moreover, the lead removal from the bush material has strongly reduced the capability of the anti friction material to accept asperity contacts. In this paper, before trying to find the pressure distributions on the oil film of piston pin bearings by the unsteady two dimensional thermohydrodynamic lubrication analysis in order to do the optimum design of the bearings of piston pin, it will be investigated the tendancy of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress.

삼각휜 열전달의 수치해석

전상명,권영필,Chun, Sang-Myung,Kwon, Young-Pil 대한설비공학회 1982 설비저널 Vol.11 No.3

One-dimensional approximation for fin problems is widely used in current texts and industrial practice. The errors caused by this approximation is analysed for a longitudinal triangular fin by the numerical solution of two-dimensional fin equation. Two-dimensional solution is obtained by the finite element method and com pared with the one-dimensional esact solution. The results show that total heat transfer and fin efficiency are overestimated by the one-dimensional approximation. The factors which cause these errors are the Biot number (Bi) and the ratio of fin length to half the thickness (L/a). When Bi is smaller than 1.0 these errors are smaller than $10\%$, but when Bi is larger than 5.0 they are a few ten percents. Fin efficiency obtaned by one-dimensional and long fin assumption is valid only then Bi is small and L/a is large.

터보챠져 저어널베어링의 설계에 관한 매개변수 연구

전상명,Chun, Sang-Myung 한국트라이볼로지학회 2007 한국윤활학회지(윤활학회지) Vol.23 No.1

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed to overcome the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. Therefore, in this study, the effects of the type of inlet oil port, inlet temperature and the sort of engine oil on the performance of a turbocharger bearing are to be investigated. It is found that the type of oil inlet ports, the control of inlet oil temperature and the selection of engine oil type play important roles in determining the temperature and pressure, then the friction and load of a turbocharger journal bearing at high speed operation.

The Design Review for Lubrication System of an Internal Combustion Engine

전상명,Chun, Sang-Myung Korean Tribology Society 2010 한국윤활학회지(윤활학회지) Vol.14 No.1

초기 엔진 개발 단계에서 양질의 엔진 개념 설계를 얻기 위해 가장 중요하게 다루는 분야가 엔진윤활시스템 설계라는 것은 지나친 말이 아니다. 그러므로 초기 개념설계 후 엔진제작에 앞서 초기 설계된 윤활시스템과 그 관련 부품에 대한 시스템 윤활해석을 수행하는 것은 필수적이다. 따라서, 본 논문에서는 초기 개념 설계된 2.0 L DOHC엔진에 대한 엔진 베어링과 윤활시스템에 대하여 수치해석적으로 유로망 해석을 하여 설계검증을 한 결과를 기술하고자 한다. It is not too much to say that, at the beginning of engine development, the most important areas for a good engine concept design is the lubrication system design. So, between right after finishing concept design and before procuring the engine, it is necessary to carry out the system lubrication analysis for the initially designed lubrication system and the related lubricating parts. Therefore, in this paper, it is to describe the results of a design review carried out the numerical net work analysis on the engine bearings and the lubrication system of an initially designed 2.0 L DOHC engine.

딥스틱게이지형 소형 엔진열화감지센서 개발

전상명(Sang Myung Chun) 한국트라이볼로지학회 2013 한국윤활학회지(윤활학회지) Vol.29 No.2

A small engine-oil-deterioration detection sensor was developed and installed at the tip of a dipstick gage. The sensor part was manufactured using printed circuit board (PCB) manufacturing technology. A set of sensor covers was installed in order to protect the sensor and realize good signal stability. The small engine-oildeterioration detection sensor system comprised a dual sensor having etched copper electrodes coated with gold and ceramic, a flexible PCB (FPCB) acting as electric wire, and a dummy PCB with only a lock connector. The sensor can easily be installed by insertion through the guide tube of a dipstick gage. Thus, a driver can easily handle it without further installation equipment. The sensor can determine the level of deterioration in the engine oil by estimating the corresponding dielectric constant of the engine oil.

오일필터 일체형 엔진오일 퇴화감지센서용 센싱시스템 개발

전상명 ( Sang Myung Chun ) 한국센서학회 2011 센서학회지 Vol.20 No.4

The purpose of this study is to develop a sensing system to measure the capacitance of a pre-developed engine oil deterioration detection sensor integrated with an oil filter. To measure the capacitance of engine oil in the sensor, it is used the way measuring the electric charging time in a capacitor by impressing DC volt. This method has merits on cost and signal stability. The measured capacitance is compensated by comparison with the one measured by an impedance analyzer. Also, using the dielectric constant gained by an impedance analyzer, the calculating equation of the dielectric constant of engine oil related with the currently developed sensor is decided. Finally, the degradation degree of engine oil is estimated according to the change rate of dielectric constant between green oil and used oil. The newly developed personal controller is to control a series of the processes.

엔진오일 유전상수 변화량 측정에 의한 엔진오일 품질 모니터링 시스템 개발

전상명(Sang Myung Chun) 한국트라이볼로지학회 2011 한국윤활학회지(윤활학회지) Vol.27 No.3

The purpose of this study is to develop an engine oil quality monitoring system to warn the abnormal condition of engine oil. To do this, first of all, it is needed a personal controller development to measure the capacitance of a pre-developed engine oil deterioration detection sensor integrated with an oil filter. To measure the capacitance of engine oil in the sensor, it is used the way measuring the electric charging time in a capacitor by impressing DC volt. This method has merits on cost and signal stability. The measured capacitance is com-pensated by comparing with the one measured by an impedance analyzer. Also, using the dielectric constant gained by an impedance analyzer, the calculating equation of the dielectric constant of engine oil related with the currently developed sensor is decided. Then, the deterioration degree of engine oil is estimated according to the change rate of dielectric constant between green oil and used oil. Finally, using this dielectric constant information together with engine oil temperature and pressure, the currently developed engine oil quality monitoring system is to tell the abnormal state of engine oil.

The Design Review for Lubrication System of an Internal Combustion Engine

Sang Myung Chun(전상명) 한국트라이볼로지학회 2010 한국윤활학회지(윤활학회지) Vol.26 No.3

초기 엔진 개발 단계에서 양질의 엔진 개념 설계를 얻기 위해 가장 중요하게 다루는 분야가 엔진윤활시스템 설계라는 것은 지나친 말이 아니다. 그러므로 초기 개념설계 후 엔진제작에 앞서 초기 설계된 윤활시스템과 그 관련 부품에 대한 시스템 윤활해석을 수행하는 것은 필수적이다. 따라서, 본 논문에서는 초기 개념 설계된 2.0L DOHC엔진에 대한 엔진 베어링과 윤활시스템에 대하여 수치해석적으로 유로망 해석을 하여 설계검증을 한 결과를 기술하고자 한다. It is not too much to say that, at the beginning of engine development, the most important areas for a good engine concept design is the lubrication system design. So, between right after finishing concept design and before procuring the engine, it is necessary to carry out the system lubrication analysis for the initially designed lubrication system and the related lubricating parts. Therefore, in this paper, it is to describe the results of a design review carried out the numerical net work analysis on the engine bearings and the lubrication system of an initially designed 2.0 L DOHC engine.

스크린 프린팅 기술을 적용한 피스톤 스커트의 브레이드 코팅공정에 관한 기초연구 - 사례연구

전상명(Sang Myung Chun) 한국트라이볼로지학회 2010 한국윤활학회지(윤활학회지) Vol.26 No.2

The purpose of this study is to find how to be formed the wet film thickness during the low friction coating process for a piston skirt with application to the theory of screen printing. In other words, in this research, it is to derive the general expressions predicting the pressure under a blade and the volume of coating fluid passing through the blade edge. Using these expressions, it is to be approved that the current operation characteristics of a screen printing system to a sample blade coating process for low friction coating on a piston skirt can be quantitatively assessed.

기유와 첨가제 혼합 전 다등급 윤활유의 성능 예측 시뮬레이션 프로그램 개발

전상명(Sang Myung Chun) 한국트라이볼로지학회 2012 한국윤활학회지(윤활학회지) Vol.28 No.2

Generally, to product multi-grade oil like engine oil, a sort of mineral base oil is mixed with a fundamental additive package liquid and a polymer liquid as viscosity index improver in order to improve the lubricating property of base oil. That is, engine oil is the mixture of more than two fluids. Specially, a polymeric type liquid cannot be seen as the linear viscosity like Newtonian fluids. In this research, by using the governing equation describing non-Newtonian hydrodynamic lubrication related with the mixture of incompressible fluids based on the principle of continuum mechanics, it will be compared the bearing performance between the mixture of each liquid to be blended and multi-grade engine oil as a single fluid in a high speed hydrodynamic journal bearing. Further, it is to be found the way estimating the performance of the blended multi-grade engine lubricant in a journal bearing in advance before blending by using the physical properties of mineral base oil, fundamental additive liquid and polymer liquid of viscosity index improver. So, it can be reduced the number of trial and error to get the wanted lubricant by selecting the proper volume fraction of each liquid to satisfy the expected performance and estimating in advance the performance of various multi-grade oils before blending. Therefore, it can be shorten the developing time and saved the developing cost.