• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.3
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• pp.94-104
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• 1994

In order to improve engine performance and its reliability it is very important to find the friction force between piston-ring assembly and cylinder wall in engine operating conditions. A new system was developed for the piston-ring assembly friction force measurement. This system had a relatively high fundamental frequency at 884 Hz and a fine resolution of 0.5N in friction force measurement. Comparing with existing floating liner systems this systems required small installation space and at the same time alleviated the system noise problem induced by the thrust and slap impulse forces.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1510-1519
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• 1994

It is important to understand the friction characteristics between piston-ring assembly and cylinder wall for the friction loss reduction as well as the solution of problem such as scuffing wear and oil consumption. A new system was developed for the piston-ring assembly friction force measurement. This system was applied to the friction force measurement to find its functional relationship with variables such as engine speed, oil viscosity, and engine load. The friction mean effective pressure(fmep) was found to have a linear relationship with$(\vpsilon{U})^{0.42}$ under motering and with$(\vpsilon{U})^{0.45}$ under firing operations, where $\vpsilon$ is the kinematic oil viscosity and U is mean piston speed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1993.12a
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• pp.35-38
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• 1993

질화규소는 고온에서 고강도, 고경도, 내열성, 내식성 등의 우수한 성질을 가지고 있기 때문에 열교환기, 공구, 기계밀봉(mechanical seal), 자동차용 엔진부품중의 피스톤 및 실린더 링 등의 중요한 부품의 재료로 크게 부목받고 있다. 이러한 질화 규소의 고온에서의 마모, 마찰거동이 중요한 부품으로의 활용범위를 넓히고 또한 기능성을 향상시키기 위해서 고온에서의 마모, 마찰거동에 대한 연구 및 이해가 절대적으로 필요하다. 공유결합성이 강한 질화규소의 소결시에 첨가되는 첨가제나 제조공정에서 들어갈 수 있는 불순물들은 소결체의 입자모양이나 입계에 존재하는 상의 점도를 변화시켜 고온에서의 기계적성질을 저하시키는 것으로 알려졌다.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.4
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• pp.66-74
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• 1990

Friction between piston-ring assembly and cylinder wall of a spark ignition engine was evaluated under various engine operating conditions utilizing a grasshopper linkage system. The friction force was estimated by the force balance relation at the small end of connecting rod. Three forces were chosen to be measured for the objective. They were gas pressure inside the cylinder, inertia force of the piston-ring assembly, and the force exerted by the connecting rod. These forces were measured by a piezo type pressure sensor, an accelerometer and strain gauges, respectively. Comparisons were made with the frictional force evaluated by the conventional method where the assumption of constant rotational speed of engines was adopted. Due to the variation of rotational speed of engines, the conventional method was found to lead to a large error in the evaluation of the frictional force.