US 2006/0232267 A1 · Determining quality of lubricating oils in use

Abstract

Resistivity ρ 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 dρ/dt>0, a maximum ρmax at a time t1 where dρ/dt=0, a second portion where dρ/dt<0, a minimum ρmin at a time t2 where dρ/dt again is zero, and a third portion where dρ/dt>0. Furthermore, there can exist another time t3, where dρ/dt exhibits a discontinuous change (increase) with time. Characteristics of the ρ vs. t curve, including, the values of t1, t2, t3, ρmax, ρmin, and the ratio ρmax/ρmin can be compared with like data on like lubricant oils in estimating the remaining useful life of the present operating lubricant oil.

Claims24

Dependent claims

A method of determining remaining useful life of a quantity of oil in use in fluid lubrication of an operating mechanism, the method comprising:

repeatedly determining resistivity (ρ) values of the oil at an predetermined oil temperature during operating time intervals of the mechanism;
recording a resistivity-time ρ(t) history of the oil such that, as successive resistivity values starting with an initial value are accumulated with elapsed operating time, a continuous ρ(t) linear curve is formulated that includes;
(1) a first portion with a slope of dρ/dt>0 up to a first time t1 during which values of ρ increase and (2) a maxima at t1 where dρ/dt=0 with a corresponding ρmax;
comparing, from time to time, the then existing portion of the ρ(t) curve with like predetermined data on a like or functionally comparable oil composition;
and
using the comparison to predict the remaining useful life of the oil.

3 more elements

Dependencies are inferred from the claim text.

Determining quality of lubricating oils in use

Life of this patent

Determining quality of lubricating oils in use

Life of this patent

Abstract

Claims24