DETERMINING QUALITY OF LUBRICATING OILS IN USE

摘要

Resistivity p values of a lubricating oil are repeatedly determined at a predetermined temperature (range) as it is in use in a working mechanism such as a vehicle engine. Such accumulated properties over operating time of the working lubricant can be plotted graphically to display a curve with, for example, a first portion where dp/dt>0, a maximum pmax at a time t/ where dp/dt=0, a second portion where dp/dt<0, a minimum pmin at a time t₂ where dp/dt again is zero, and a third portion where dp/dt>0. Furthermore, there can exist another time t₃, where dp/dt exhibits a discontinuous change (increase) with time. Characteristics of the p vs. t curve, including, the values of t₁, t₂, t₃, pmax, Pmin, and the ratio pma?/pmin can be compared with like data on like lubricant oils in estimating the remaining useful life of the present operating lubricant oil.