Evaluation and quantification of friction using Ionic Liquids in small, self lubricating journal bearings

Four low viscosity Ionic Liquids were evaluated as lubricants in self lubricating porous journal bearings. Precise friction measurements performed under boundary conditions close to applications are presented under variation of the fluid gap and radial loading both in the domain of hydrodynamic and mixed lubrication up to high speed and high shear rates. A comparison to a standard lubricant and verification using a Newtonian reference is given and lowest friction was found for the low viscosity Ionic Liquids at the speed of minimum friction. Applying a thermohydrodynamic friction model, Newtonian fluid behavior was found for the Ionic Liquids in the hydrodynamic domain of lubrication up to high shear rates. •Application of Ionic Liquids as Lubricant in small self-lubricating porous journal bearings.•Thermohydrodynamic friction model using a lumped parameter thermal model for determination of lubricant temperature.•Detection of friction and displacement between shaft and bearing allow detecting whirling and its effects on friction.