Friction Power Loss of Mineral and Synthetic Lubricants in a Running Engine

The performance of single grade and multigrade oils and synthetic oils, has been evaluated in terms of friction power loss using an engine running on the test bed according to a modified Morse procedure. The results obtained show a good correlation between the engine performance and the rheological properties of the lubricants.

The very low friction power loss experienced when using lubricants containing polymer can be explained by introducing the concept of anisotropic effective viscosity.

Based on the good correlation between the measured and calculated friction generated in main bearings, a method has been devised for evaluating the temporary viscosity losses of multigrade oils by measuring the engine friction power loss and bearing temperatures.