The continuously variable transmission (CVT) of automobile relies on the friction between steel belt and pulley to transmit torque. Anti-wear agents, detergents, and friction modifiers in continuously variable transmission fluid (CVTF) are all surfactants, and their competitive or synergistic adsorption on the tribosurface has a significant impact on the friction transmission torque. This study investigated the effects of the combination of butylated triphenyl phosphorothionate anti-wear agent, Ca detergent, and partial ester friction modifier on the tribological characteristics of a CVTF. The worn surface was analyzed by 3D profiler, SEM, EDS, and XPS. QCM-D was used to detect the adsorption relationship of the three additives. The mechanism of butylated triphenyl phosphorothionate on friction transmission and anti-wear performance was deduced.
