Development of ASTM Standard Test Methods for Measuring Engine Oil Viscosity Using Rotational Viscometers at High-Temperature and High-Shear Rates

Abstract

Two ASTM standards have been developed for the measurement of engine oil viscosity at high temperature (150°C) and high shear rate (106 s-1) using rotational viscometers. Both methods resulted from significant international participation at the working group level. One test method resulted from work done primarily within ASTM Committee D-2, Subcommittee 7, using the tapered bearing simulator. The other resulted from work done within the Co-ordinating European Council (CEC) using the Ravenfield viscometer, herein called the tapered plug viscometer. The chronological development of each standard is reviewed, and test method and precision are compared. Expansion of measurement capabilities are discussed with regard to the study of lubricant rheology and engine performance.

Shear Thinning and Hydrodynamic Friction of Viscosity Modifier-Containing Oils. Part I: Shear Thinning Behaviour

“…This meant that the shear thinning behaviour of VM solutions could not be fully explored. Typical flow curves of engine oils up to 10 6 s −1 can be found in [8][9][10][11]. This limitation has recently been addressed by the development of the PCS ultrashear viscometer (USV) that is able to reach 10 7 s −1 .…”

Study of Permanent Shear Thinning of VM Polymer Solutions

“…Viscometers based on this geometry have been employed since the 1980s to measure the viscosity of lubricants up to 10 6 s -1 [55,56] and, more recently, up to 10 7 s -1 [57]. In a recent study, it was shown that the application of shear rates above 10 6 s -1 in a concentric cylinder viscometer results in significant permanent viscosity loss of polymer solutions and that this can be used to compare the shear stability of VMs [58].…”