A Method for Determining the Influence of Multigraded Oils on Journal Bearing Performance

An experimental technique has been developed to measure the minimum oil film thickness of dynamically loaded journal bearings. Inductive transducers were used to measure the motion of the journal within the bearing clearance and with this information the relative oil film thickness was determined. The measured film thickness correlated closely with analytically predicted values for five base oils. However, tests on four oils which met the SAE multiviscosity engine oil classification (three SAE 10W-30 and one SAE 10W-40) showed that the low shear rate viscosity of these oils could not be used to predict the bearing oil film thickness developed by these oils.