A Study of Lubricating Oil Performance in a Journal Bearing Rig

Several polymer-containing oils have been studied in a journal bearing rig under hydrodynamic lubrication conditions. For shear rates up to 2.5 x 10⁵ s^-1 and oil film thicknesses down to 2 μm, these oils showed the same behaviour as polymer free oils.

In a second series of experiments, the bearing was provided with a suitable lining and experiments were carried out under boundary lubrication conditions. Bearing wear could be determined by weighing of the bearing shells, and the results obtained show that for Newtonian lubricants wear increases markedly with decreasing viscosity. The influence of the performance package was demonstrated by two SAE 30 grades. A decrease in wear of about 60 % was effected by a change of the performance package. For non-Newtonian lubricants the wear level is lower than expected on the basis of high shear viscosity alone; an attempt to explain this behaviour should take into account non-Newtonian effects and possibly the presence of films of adsorbed material.