US 7,259,575 B2 · Method for on-line fuel-dilution monitoring of engine lubricant

Abstract

A method for determining a fuel-dilution condition of a lubricant used in transportation and industrial equipment. The method uses apparatus that applies a high frequency and optionally a low frequency oscillating signal to electrodes immersed in the fluid and quantifies fluid response to the signals. Apparatus can further include means to control the lubricant temperature, or a temperature sensor to monitor the lubricant temperature at the electrodes. The method monitors response of the lubricant to the applied electrical signals and determines ratios of lubricant properties. The high-frequency lubricant property ratio or change of high frequency lubricant property as a function of a lubricant use-measure is compared to a predicted ratio based on lubricant use and an estimate of the lubricant's fuel dilution determined. The optional low-frequency lubricant property ratio is compared to thresholds to determine when the lubricant loses the ability to control fuel dilution. The method outputs information relevant to the fuel-dilution condition of the lubricant.

Claims23

Dependent claims

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.

1 more element

An apparatus that monitors and detects the fuel-dilution condition of a lubricant comprising:

d. applying a high-frequency voltage signal between electrodes immersed in a fluid,
e. measuring a lubricant 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
f. comparing at least one of the following 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 a 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.

1 more element

Dependencies are inferred from the claim text.

Method for on-line fuel-dilution monitoring of engine lubricant

Life of this patent

Method for on-line fuel-dilution monitoring of engine lubricant

Life of this patent

Abstract

Claims23