Influence of the Viscosity of Polymer Containing Engine Oils on the Startability of Engines

Investigations using 4 monograde and 3 multigrade engine oils were performed by cold cranking an automotive engine to determine whether or not there is friction reduction due to the pseudoplastic behaviour of the multigrade engine oils. A comparison of the oils using viscometers indicated the viscometers ability to predict the “engine viscosities” over a temperature and shear rate range. Furthermore, this work determined whether results of viscometric measurements could be confirmed with the test engine. An answer was found to the question of the amount of hydrodynamic friction encountered when starting an automotive engine at low temperatures.