A fundamental requirement for film generation in elastohydrodynamic lubrication (EHL) is that the viscosity of the liquid increase strongly with increase in pressure. The pressure dependence of viscosity influences both the thickness of the film separating the machine elements and the friction force which opposes their relative motion. Oddly, accurate descriptions of the piezoviscous effect were not employed in the study of EHL until about ten years ago. Advances in understanding film formation and friction are now proceeding quickly and the demand from industry for this information is growing. Molecular dynamics simulations have the promise of generating pressure-viscosity data for liquids which have not yet been synthesized but only if the accuracy of the method can be validated. (C) 2019 Elsevier B.V. All rights reserved.