Tribological Performance of Esters, Friction Modifier and Antiwear Additives for Electric Vehicle Applications

Abstract

The replacement of conventional lubricants with esters is an alternative to provide a low environmental impact and at the same time excellent lubricity features, the high solubility of additives, good viscosity index, low volatility, and high thermal stability. Friction modifiers and antiwear/extreme pressure additives are extensively used to save energy and increase operational life in machine components. In this study, the lubricity of a Group IV base oil containing ester and various benchmark friction modifiers and/or antiwear/extreme pressure additives is measured to evaluate the influence of the ester on the tribological performance of the mixture components. The tribological performance is discussed based on the tabulation of the traction coefficient using a Mini-Traction-Machine and on the measurement of the specific wear rate from the wear scar of the experimental studies using an optical profilometer. In general, results show synergies between the ester and the additive formulations, reducing the wear rate to 75% and decreasing the traction coefficient a 20 to 50%, depending on the evaluated additive.