SEDL / STP / STP621_S1-EB / STP32382S

A Mathematical Technique for Comparing Shear Stability in Bench Tests and Service

Rein, SW
Texaco Inc.,

Randall, NP
Texaco Inc.,

Marshall, HT
Texaco Inc.,

Lewis, BJ
Texaco Inc.,

Pages: 12    Published: Jan 1977

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Abstract

Viscosity decrease as a function of the duration of mechanical shearing is described by a mathematical model. Applicability of the model to several different types of service is demonstrated. For automobile engine oil service that shows a viscosity decrease initially, followed by a gradual viscosity increase, the model offers a means of separating the viscosity decrease term from the total viscosity change. The model provides a rational method of comparing shearing in bench tests with shearing in service. It also offers a means for detailed comparisons of the shear stability of different lubricants in a given service.