Patent ID: 7259575
Filing Date: 2007-08-21
Classification: F01M,G01N

Abstract:
1. A method for determining the fuel-dilution condition of a lubricant comprising: a. applying a high-frequency voltage signal between electrodes immersed in a fluid, b. measuring the lubricant dependent response to the applied high-frequency signal and determining a ratio of a high-frequency lubricant property to the high-frequency property when the lubricant is fresh, and c. comparing at least one of the following properties selected from the group consisting of the determined high-frequency lubricant property ratio to a ratio predicted based on use since the lubricant was fresh, a change in the determined high-frequency lubricant property ratio as a function of use to a change predicted use-based change, and combination thereof, to estimate the fuel content of the lubricant, wherein the applied signal is selected from at least one of the group consisting of essentially sinusoidal with an essentially defined frequency, essentially non-sinusoidal of frequency defined by the Fourier-transform base frequency, and combination thereof wherein each step is conducted continuously, intermittently, repeatedly and combinations thereof.