Effects of Temperature on the Tribological Properties of Cylinder-Liner Piston Ring Lubricated with Different Oils

As one of the important friction pairs of a diesel engine, the cylinder-liner piston ring (CL-PR) faces a harsh high-temperature working environment. To explore the mapping relationship between the friction performance of the CL-PR and the change in temperature, the reciprocating-friction and wear-testing machine was used to analyze the friction performance and lubrication performance of four kinds of lubricating oil at different temperatures (room temperature, 60 degrees C, 90 degrees C, and 120 degrees C) from the friction coefficient, contact resistance and surface topography. The results show that the tribological properties of the four lubricating oils show different trends with the increase in temperature. The friction coefficient of the base oil first decreases and then increases with the increase in temperature; this shows that the friction property of the base oil is improved by a certain temperature rise, and the increase in temperature promotes the formation of an oxide film and reduces the friction coefficient. While the friction coefficient of other three lubricating oils with specific application scenarios increases first and then remains stable, the wear of the friction pair is the most severe at 120 degrees C. The wear forms are abrasive wear and adhesive wear.

Automated summary

As an important friction pair in a diesel engine, the cylinder-liner piston ring (CL-PR) operates in a challenging high-temperature environment. In order to understand the relationship between the friction performance of the CL-PR and temperature changes, a reciprocating-friction and wear-testing machine was used to analyze the friction and lubrication performance of four different lubricating oils at various temperatures (room temperature, 60 degrees C, 90 degrees C, and 120 degrees C) based on friction coefficient, contact resistance, and surface topography. The results show that the tribological properties of the lubricating oils exhibit different trends as temperature increases. The friction coefficient of the base oil initially decreases and then increases with temperature, indicating improved friction performance due to a certain temperature rise, as well as the promotion of oxide film formation and reduction in friction coefficient with temperature. On the other hand, the friction coefficient of the other three lubricating oils initially increases and then stabilizes, with the most severe wear observed at 120 degrees C in the form of abrasive wear and adhesive wear.