Differential carrier temperature sensing method

• US 9,651,142 B2
• Filed: 03/05/2014
• Issued: 05/16/2017
• Est. Priority Date: 03/11/2013
• Status: Expired due to Fees

• Current Assignee: Dana Automotive Systems Group, LLC (Dana, Inc.)
• Original Assignee: Dana Automotive Systems Group, LLC (Dana, Inc.)
• Inventors: Paielli, Perry M., Beesley, Peter A.
• Primary Examiner(s): Verbitsky, Gail Kaplan
• Application Number:
  US14/197,586
• Publication Number:
  US 20140254623A1
• Time in Patent Office: 1,168 Days
• Field of Search: 374178, 374137, 374 29, 374 30, 374185, 374163, 374 44, 374208, 374 10, 374 31- 33, 374165, 702130
• CPC Class Codes: F16H 57/01 Monitoring wear or stress of gearing elements, e.g. for triggering maintenance
• CPC Class Codes: F16H 57/0405 Monitoring quality of lubricant or hydraulic fluids
• CPC Class Codes: F16H 59/72 dependent on oil characteristics, e.g. temperature, viscosity
• CPC Class Codes: F16H 61/0006 Electronic control units for transmission control, e.g. connectors, casings or circuit boards
• CPC Class Codes: G01K 7/427 Temperature calculation based on spatial modeling, e.g. spatial inter- or extrapolation
• CPC Class Codes: G01N 25/72 Investigating presence of flaws
• CPC Class Codes: H05K 7/20854 Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20863 takes precedence

Abstract

A method of sensing an internal temperature of a differential carrier includes providing a differential carrier temperature sensing package with an electronic circuit board having a first temperature sensor that is in thermally conductive contact with a thermal conductor, where the thermal resistance of the package and thermal conductor is given and known as R_ENC. The package is extended through an opening in a differential carrier that has a fluid in it. The first temperature sensor senses a differential fluid temperature T_SNS. The electronic circuit board further has a second temperature sensor, whereby the thermal resistance of the circuit board is a given known resistance R_PCB. The second temperature sensor senses an internal package temperature T_PCB within the package. Consequently, an internal temperature of the differential is calculated from the equation: T_INT=T_SNS(1 R_ENC/R_PCB)−T_PCB(R_ENC/R_PCB).

Claims

1. A differential carrier temperature sensing package comprising:

a package housing comprising an upper portion and a lower portion connected together to form a sealed package housing, the upper portion and the lower portion in thermally conductive contact with an environment external to a differential carrier housing, the lower portion in thermally conductive contact with an outer surface of the differential carrier housing, and the lower portion extended through an opening in the differential carrier housing, wherein the lower portion is in thermally conductive contact with fluid within the differential housing;

an electronic circuit attached to the upper portion within the package housing and in thermally conductive contact with the upper portion of the package housing;

a first temperature sensor disposed on and in thermally conductive contact with the electronic circuit and in thermally conductive contact with a thermal conductor imbedded in and in thermally conductive contact with the lower portion, the lower portion in thermally conductive contact with fluid within the differential housing; and

a second temperature sensor disposed on the electronic circuit, wherein a measured differential carrier fluid temperature T_SNS, a measured internal package housing temperature T_PCB, a known housing plus thermal conductor thermal resistance R_ENC, and a known thermal conductor resistance of the housing at the electronic circuit board R_PCB are utilized to determine an internal differential carrier temperature T_INT, by way of the equation T_INT=T_SNS (1 R_ENC/R_PCB)−

T_PCB (R_ENC/R_PCB).

2. The differential carrier temperature sensing package of claim 1, wherein the upper and lower portions of the package housing are sealed together.

3. The differential carrier temperature sensing package of claim 1, wherein the upper and lower portions of the package housing are unitary.

4. The differential carrier temperature sensing package of claim 1, wherein the upper portion comprises a thermally conductive metal.

5. The differential carrier temperature sensing package of claim 1, wherein the first and second temperature sensors comprise negative temperature coefficient thermistors.

6. The differential carrier temperature sensing package of claim 1, wherein the thermal conductor comprises an aluminum rod separated from mechanical contact with an outer surface of the lower portion of the package housing, wherein a thermally conductive contact path from fluid within the differential carrier to the environment external to the differential carrier housing is by way of the lower portion of the package housing, thermal conductor, first temperature sensor, electronic circuit, and upper portion of the package housing.

7. The differential carrier temperature sensing package of claim 1, wherein the internal housing package temperature T_PCB is by way of the electronic circuit and the second temperature sensor;

the differential carrier fluid temperature T_SNS is by way of the lower portion of the package housing, thermal conductor, first temperature sensor, and electronic circuit; and

the internal differential carrier temperature T_INT is by way of the differential carrier fluid temperature T_SNS, known thermal resistance of housing and thermal conductor R_ENC, known thermal resistance of housing at electronic circuit board R_PCB, and internal housing package temperature T_PCB.

8. The differential carrier temperature sensing package of claim 1, wherein the differential carrier fluid is selected from a group consisting of a mineral—

standard base lubricant and a synthetic—

premium lubricant.

9. The differential carrier temperature sensing package of claim 1, wherein the differential carrier fluid is certified from a group consisting of an API GL5 classification oil and SAE J2360 standard oil.

10. A differential carrier temperature sensing package, comprising:

a package housing comprising an upper portion and a lower portion connected together to form a sealed package housing, the upper portion and lower portion of the package housing in thermally conductive contact with an environment external to a differential carrier housing, the lower portion of the package housing also in thermally conductive contact with an outer surface of the differential housing, and the lower portion of the package housing extends through an opening in the differential housing, wherein the lower portion is in thermally conductive contact with a fluid within the differential housing;

an electronic circuit attached to the upper portion within the package housing and in thermally conductive contact therewith;

a first temperature sensor disposed on the electronic circuit and in thermally conductive contact with an outward projection of the lower portion of the package housing, the lower portion of the package housing in thermally conductive contact with a thermal conductor disposed in the fluid within the differential housing; and

a second temperature sensor disposed on the electronic circuit, wherein a measured differential carrier fluid temperature T_SNS, a measured internal package temperature T_PCB, a known housing plus thermal conductor thermal resistance R_ENC, and a known thermal conductor resistance of the housing at the electronic circuit board R_PCB are utilized to determine an internal differential carrier temperature T_INT, by way of the equation T_INT=T_SNS (1 R_ENC/R_PCB)−

T_PCB (R_ENC/R_PCB).

11. The differential carrier temperature sensing package of claim 10, wherein the thermal conductor has an inward thermal conductor portion disposed thereon, the inward thermal conductor portion disposed within the fluid on an inward end of the thermal conductor.

12. The differential carrier temperature sensing package of claim 10, wherein the upper and lower portions of the package housing are sealed together.

13. The differential carrier temperature sensing package of claim 10, wherein the upper and lower portions of the package housing are unitary.

14. The differential carrier temperature sensing package of claim 10, wherein the upper portion comprises aluminum and the lower portion comprises a high temperature plastic.

15. The differential carrier temperature sensing package of claim 10, wherein the first and second temperature sensors comprise negative temperature coefficient thermistors.

16. The differential carrier temperature sensing package of claim 10, wherein the thermal conductor comprises an aluminum rod that is in mechanical contact with an outer surface of the lower portion of the package housing, wherein thermally conductive contact from fluid within the differential carrier to the environment external to the differential carrier housing is by way of the thermal conductor, lower portion of the package housing, first temperature sensor, electronic circuit, and upper portion of the package housing.