Apparatus for measuring soot concentration in engine oil

• US 4,281,533 A
• Filed: 01/14/1980
• Issued: 08/04/1981
• Est. Priority Date: 01/14/1980
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Eesley, Gary L., Buchholz, Jeffrey C., DeMaggio, Gregory B.
• Primary Examiner(s): Goldstein, Herbert
• Application Number:
  US06/112,131
• Time in Patent Office: 568 Days
• Field of Search: 73/15 R, 73/61 R, 73/64, 73/359 R
• US Class Current: 73/61.76
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: G01N 25/18 by investigating thermal conductivity by calorimetry G01N25/20; by measuring change of resistance of an electrically-heated body G01N27/18
• CPC Class Codes: G01N 33/2888 Lubricating oil characteristics, e.g. deterioration lubricating properties G01N33/30

Abstract

Both junctions of a thin film thermocouple are formed on one side of a glass substrate. That side of the substrate is exposed to the diesel engine oil the soot content of which is to be measured. A light source on the other side of the substrate has its radiation directed through the substrate to a location at one of the junctions so that the light is absorbed by the oil adjacent that junction to a degree determined by its soot content. The temperature of the oil and the adjacent junction are increased by an amount dependent on the soot concentration and the thermocouple output is therefore a measure of the soot concentration in the engine oil.

Claims

1. Means for measuring soot concentration in engine oil comprising

a thin film thermocouple formed on one side of a transparent substrate and having first and second spaced junctions, the side of the substrate bearing the thermocouple being immersed in oil,

means for heating the oil adjacent the first junction by an amount dependent on the soot concentration, the heating means including a source of radiation to which the substrate as well as clean oil is substantially transparent and which is absorbed by soot, and means for passing the radiation therefrom through the substrate into the oil adjacent the first junction whereby the first junction is heated when soot is present in the oil,

and means for measuring the thermocouple net voltage which is a measure of the soot concentration in the oil.

2. Means for measuring soot concentration in engine oil comprising,

means for heating oil in a local zone including a source of radiation directed into the local zone whereby soot in the oil absorbs the radiation and heats the oil by an amount dependent on the soot concentration,

means for measuring the oil temperature increase due to the absorbed radiation comprising a thin film thermocouple formed on a substrate and having first and second spaced junctions immersed in the oil, the first junction being disposed in intimate heat transfer relation to the oil in the local zone so that the first junction is affected by the said oil temperature increase and the second junction is essentially unaffected by the temperature increase to thereby generate a thermocouple voltage corresponding to the temperature increase,

and means for measuring the thermocouple net voltage which is a measure of the soot concentration in the oil.

3. Means for measuring soot concentration in engine oil comprising,

means for heating oil in a local zone including a source of radiation directed into the local zone whereby soot in the oil absorbs the radiation and heats the oil by an amount dependent on the soot concentration,

means for measuring the oil temperature increase due to the absorbed radiation comprising a thin film thermocouple formed on one side of a substrate transparent to the said radiation and having first and second spaced junctions immersed in the oil, the radiation source being on the other side of the substrate for projecting radiation through the substrate toward the local zone, and means comprising an aperture in the first junction for coupling the radiation into the oil in the local zone, the first junction being disposed in intimate heat transfer relation to the oil in the local zone so that the first junction is affected by the said oil temperature increase to generate a corresponding thermocouple voltage,

and means for measuring the thermocouple net voltage which is a measure of the soot concentration in the oil.