| abstract |
A method for testing a sample for soot-related viscosity increase comprising: (a) preparing the sample which comprises a major amount of an oil of lubricating viscosity, (b) measuring the viscosity of the sample (c) preparing a stable sample/paste dispersion of the sample and a carbon black paste, (d) equilibrating the sample/paste dispersion, and (e) measuring the viscosity of the sample/paste dispersion, and a method for predicting physical effects of soot-loading on a sample in a test which measures viscosity increase comprising: (1) measuring viscosity increase for a series of reference fluids in the test, (2) measuring viscosity increase for the series of reference fluids in a method having steps (a) to (e), (3) developing a curve, (4) evaluating the sample using the method having steps (a) to (e), and (5) interpolating a viscometric effect for the sample using the curve. |