US 7,064,562 B2Granted

Temperature compensation method for soot sensor

AssigneeDelphi Technologies, Inc.

InventorsYingjie Lin, Nicte Salvador

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Abstract

Certain characteristics of Diesel engine lubrication oil are determined. A sensor formed as a capacitor is immersed in the oil. An inductor is in series with the sensor, and a high frequency voltage with a varying frequency is applied to the resonance circuit formed by the inductor and capacitor. Resonance is sensed, and the resonant frequency and/or the resonant current are used to determine the soot content and/or the dielectric constant of the oil. The electronics temperature can be used to compensate for temperature variations in the resonant frequency and the electronics temperature and the oil temperature can be used to compensate for temperature variations in the resonant current. The compensated values are preferably used in the determination of soot content and the dielectric constant.

Claims25

Dependent claims

A method for determining characteristics of Diesel engine lubrication oil, comprising the steps of:

immersing a capacitor in the oil such that the oil provides a dielectric between the plates thereof;
connecting an inductor in series with the capacitor, wherein the capacitor and the inductor collectively provide a resonance circuit;
varying a frequency of a high frequency voltage applied to the resonance circuit;
sensing a temperature of the inductor;
sensing when the resonance circuit is at resonance to thereby obtain at least one of a resonant frequency and a resonant current;
compensating at least one of the resonant frequency and the resonant current for the temperature of the inductor;
and
using at least one of the compensated resonant frequency and the compensated resonant current to determine at least one of a soot content and a dielectric constant of the oil.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/909,272Filed 30 Jul 2004 · continuation in part
Priority: 4 Dec 2002
Published: US 2005/0017738 A127 Jan 2005
Granted: 20 Jun 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G01N 33/2888
Oils , i.e. hydrocarbon liquids: lubricating oil characteristics, e.g. deterioration
G01N 27/02
Investigating or analysing materials by the use of electric, electrochemical, or magnetic means: by investigating impedance
G01N
Investigating or analysing materials by determining their chemical or physical properties

Family

Application10/310,126Parent of this continuation-in-part · filed 4 Dec 2002
US 2005/0017738 A1Pre-grant publication · published 27 Jan 2005
US 6,867,603 B2Parent of this continuation-in-part · filed 15 Mar 2005
US 2004/0108859 A1Published application
US 7,064,562 B2This patent

From the US filing history. Foreign family members aren’t listed.