Numerical Study of Thermal Effect on the Friction of Piston-cylinder Contact in an Internal Combustion Engine

Abstract

For the different operating regime of an internal combustion engine, the compartment ‘Piston-Ring-Liner’ represents the largest share of frictional power loss. This study presents a numerical analysis of ThermoHydroDynamic (THD) lubrication of an internal combustion engine piston to evaluate the thermal effect on the friction of piston-cylinder contact by considering three thermal models: isothermal, Global Thermal (GT) and THD. The results show that the choice of the thermal model has a great influence on the tribological characteristics of the piston-cylinder contact. The transition from the isothermal model to the THD model will lead to a decrease of approximately 6% of the minimum oil film thickness and an increase of 4% of the hydrodynamic pressure, and the transition from the GT model to the THD model will decrease 30% of the friction force in the piston-cylinder contact during an engine cycle.

Keywords

• Friction
• Lubrication
• Piston-Liner
• Thermohydrodynamic model
• Viscosity