• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2000.06a
• /
• pp.227-236
• /
• 2000

The secondary motion of piston greatly influences the dynamic and frictional performances of an engine. The motion is very related to the clearance, sliding velocity and skirt profile, etc. In our work, piston dynamics is analyzed with the commercial analysis software, PISDYN by Ricardo Consultant Engineers, Inc. The effects of profiles with piston pin offsets are studied regarding the secondary motion of piston and several results are compared.

• Tribology and Lubricants
• /
• v.22 no.4
• /
• pp.203-210
• /
• 2006

Two kinds of crankshaft oil supply system which were called continuous and discontinuous oil sup-ply system have recently been adopted in engine developing process. In order to clarify the lubrication characteristics for theses systems, in this paper, the comparison studies on supplied oil temperature, pressure, aspect ratio of bearings, and radial clearance were carried out for the main and the connecting rod bearing using computational fluid dynamic analysis.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1997.04a
• /
• pp.247-252
• /
• 1997

최근 자동차 배기 가스에 대한 규제가 강화되고 있고, 특히 자동차 매연중 대젤 차량에 대한 배기 가스 저감이 관심의 대상이 되고 있다. 이러한 배기 가스 규제에 대응하기 위하여 엔진의 여러 부위에 대한 설계변경이 이루어지고 있다. 설계변경의 대표적인 예로는 피스톤 탑 링(top piston ring)의 위치를 현재보다 위로 하고 피스톤과 라이너 사이의 간극을 좁게하여 크레비스 볼륨을 줄이거나, 연로 분사 시기 지연, 배기가스재순환(EGR, Exhaust Gas Recirculation)장치 등이 있다. 본 보고에서는 모사 실험 결과에 추가하여 엔진 시험을 수행함으로써 엔진유의 분산 특성및 산화안정성에 미치는 기유와 첨가제의 영향을 조사하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1994.06b
• /
• pp.66-71
• /
• 1994

The motion of dynamically loaded journal in the connecting rod big-end bearings is considered and then equations of motion are derived. Dynamical characteristics of big-end bearings are derived by perturbation method and linearized spring and damping coefficients are calculated. Numerical intergrations of equations of motion ure performed by $\rho$-family method. This paper gives various journal orbits in a big-end bearing depending on external force cycle and bearing parameters

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1996.04b
• /
• pp.117-120
• /
• 1996

본 연구에서는 VHVI기유, 용재 추출로 제조된 기유를 사용하는 엔진유 3종을 대상으로 하여 엔진유가 배기 가스에 미치는 영향을 연구하였다. 본 연구를 통하여 얻은 결과는 다음과 같다. 1. 엔진유의 증발감량에 따라 엔진 배기 가스에 미치는 영향은 각기 다르게 나타났다. 2. 저증발 감량의 특성을 가지는 VHVI 기유를 사용한 엔진유는 고속, 전부하(3000 rpm, 37.5 kW)조건에서 NOx 저감 효과가 있다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1996.04b
• /
• pp.113-116
• /
• 1996

기유의 soot 분산 성능 실험과 엔진유의 산화 및 분산성 실험을 하여 다음과 같은 결론을 얻었다. 1. 윤활기유는 soot의 분산 성능에 매우 큰 영향을 미치며 고급 기유일수록 soot의 함량이 클수록 우수한 성능을 보인다. 2. VHVI 기유는 산화 시험 시간이 경과할수록 광유계 기유보다 우수한 산화안정성을 나타낸다. 3. 산화방지제는 산화방지뿐 아니라 분산성에도 영향을 미친다. 4. 광유계 기유를 사용한 경우 ZnDDP는 산화 방지 및 분산성을 향상 시키지 못하나 VHVI 기유에 ZnDDP를 투여한 경우에는 산화방지효과와 분산성능을 향상시킨다.

• Tribology and Lubricants
• /
• v.37 no.6
• /
• pp.246-252
• /
• 2021

Among the engine components of an internal combustion engine, the valve train is a series of systems that supply intake gas to the combustion chamber and operate intake and exhaust valves that discharge exhaust gas. If excessive wear occurs in the valve train system, the suction and exhaust valves do not open and close on time, which leads to abnormal combustion and exhaust gas. In this study, we conduct experiments and analyses on friction and wear characteristics of the valve train system. Moreover, we experimentally study the correlation between the pinball and pinball cap on engine oil lubrication, friction experiment, wear amount analysis, and surface analysis. Specifically, we experiment using Ball on reciprocating tribo-tester and apply commercial engine oil sold on the market engine oil. We construct the experimental conditions for each new oil and oil. Accordingly, the completed specimen was subjected to a confocal microscope to check the wear volume, observe the surface of the specimen, and confirm the elemental components using a scanning microscope (SEM) and an energy dispersion X-ray spectrometer (EDS). Through this experiment, we analyze the friction and wear characteristics of valve train components according to engine oil grade, and the obtained data serve as an effective engine oil management method.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1991.06a
• /
• pp.55-59
• /
• 1991

실중적으로 하중을 받는 선접촉부의 윤활명성은 johnson chart, 또는 Hooke의 Chart에서 나타난바와 같이 강체$\cdot$점도일정명감 (Rigid-Isovicosity region), 점도변화 명성 (Elasticity-Variable Viscosity Region), 탄성체$\cdot$점도일정명성 (Elasticity-Isoviscosity Region)으로 분산 되어지는데 명성내에서 2차원 선접촉의 경우 탄성 파라메터 ge가 적고 점성 파라미터 gv가 큰 Tribology적인 실제 문제가 많은데 비하여 이 점성에서의 윤활특성에 관한 수치적인 Simulation이나 실험적인 보고가 거의 없는 실정이다. 예를들면 engine의 Piston Ring과 Cylinder 간의 윤활, Vane 식의 유압펌프등에서 볼수 있는 습동부의 윤활, Rotary Engine의 Rotor 선단부분, Rotary Compressor의 Rotor와 stator간의 상대운동 점성에서 나타나는 Tribology적인 점성은 대부분이 강체$\cdot$점도 변화점성이거나 그에 바로 인접한 탄생체$\cdot$점도 변화의 초기 점성에 분포하고 있다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.409-410
• /
• 2002

In order to measure the oil-film pressure in sliding surface of machinery, we have developed a piezo-resistive type thin-film pressure sensor. To reduce the measurement error due to temperature and strain, the constituent of the pressure sensitive alloy was optimized and a new sensor shape was devised. In this study, we present the measurement results of the oil-film pressure distribution in engine connecting rod big-end bearing and piston pin- bosses with 3 different pin-boss shapes using the newly developed thin-film pressure sensor.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.267-268
• /
• 2002

Engine testing of new low-sulfur, low-phosphorus anti wear components is expensive and time consuming so bench testing of potential candidates is highly desirable as a first step evaluation. Electrical contact resistance (ECR) has been shown to be a convenient method to assess antiwear film formation in a ball-on-flat bench wear test. Correlation of the bench test to fired engines was demonstrated for lubricants varying only in the type of detergent. Previous papers have examined film formation by one and two component formulations of zinc dialkyldithiophosphate (ZnDTP) and detergents. In this study, the ECR technique is systematically extended to formulations including ZnDTP, detergent, and dispersant. Both type and level of components are considered and the implications for engine performance are discussed.