Friction and film‐forming behaviour of five traction fluids

There is growing interest in the use of toroidal‐type traction drives to provide continuously variable transmissions for use in medium‐ to high‐power automotive engines. These transmissions require the use of specially designed traction fluids to provide high friction in full‐film elastohydrodynamic lubricated contacts. This study has measured the film‐forming and traction properties of five commercially available and developmental traction fluids to provide data needed to predict their performance in traction drives. Some differences in performance between the fluids have been noted.