Fuel level measurement device

• US 7,409,860 B2
• Filed: 02/14/2006
• Issued: 08/12/2008
• Est. Priority Date: 02/14/2006
• Status: Expired due to Fees

• Current Assignee: TI Group Automotive Systems LLC
• Original Assignee: TI Group Automotive Systems LLC
• Inventors: Johansen, Mark R., Ferreira, David M.
• Primary Examiner(s): Williams; Hezron E.
• Assistant Examiner(s): Frank; Rodney T
• Application Number:
  US11/353,345
• Publication Number:
  US 20070186647A1
• Time in Patent Office: 910 Days
• Field of Search: 733/13, 733/225
• US Class Current: 73/313
• CPC Class Codes: F02M 37/103 Mounting pumps on fuel tanks
• CPC Class Codes: G01F 23/36 using electrically actuated indicating means G01F23/38 takes precedence

Abstract

A fuel level measurement device has a fuel level sensor carried by a fuel level float at the distal end of a pivoting float arm of the device which is preferably part of a fuel pump module located inside of a fuel tank preferably for automotive applications. Preferably a sealed arcuate chamber of the float is defined between an electrically conductive cover and a variable electric resistor which preferably is a generally non-conductive ceramic substrate that carries an electrically resistive ink strip. A track exposed in the arcuate chamber has a concave shape that generally faces upward so that a rolling member changes position due to the forces of gravity within the chamber as the float arm pivots generally up and down with changing fuel levels in the tank. The rolling member is electrically conductive and completes the circuit between the electrically conductive cover and the variable resistive ink strip. The sealed chamber provides the pathway for the rolling member and preferably at least in part the buoyancy for the float.

Claims

1. A fuel level measurement device for a fuel tank comprising:

an arm having one end configured to be carried pivotally by a body and a distal end;

a float housing carried by the arm adjacent the distal end and defining a sealed chamber providing buoyancy generally upon a surface of fuel in the tank;

a cupped track carried by the housing within the chamber and opening generally upward;

a gravity responsive, electrically conductive, member that changes position along the track with changing elevation of the float housing;

an electrical conductor exposed in the chamber and extending along the length of the track;

a variable electrically resistive ink strip exposed in the chamber and extending along the length of the track; and

the gravity responsive member is in movable electrical contact with the resistive ink strip at a first point and in movable electrical contact with the electrical conductor at a second point to provide an electrically conductive path generally of the member and between the ink strip and the conductor for electrical circuit completion.

2. The fuel level measurement device set forth in claim 1 wherein the electrical conductor is a metallic cover.

3. The fuel level measurement device set forth in claim 2 further comprising a non-conductive substrate of the housing engaged sealably to the cover along a perimeter, defining in part the chamber and carrying the variable electrically resistive ink strip exposed in the chamber.

4. The fuel level measurement device set forth in claim 3 wherein the gravity responsive member is a metallic ball disposed between the resistive ink strip and the metallic cover.

5. The fuel level measurement device set forth in claim 1 wherein the body is a fuel pump module located inside a fuel tank.

6. The fuel level measurement device set forth in claim 3 wherein the non-conductive substrate is a ceramic substrate.

7. The fuel level measurement device set forth in claim 6 wherein the cover is sealably soldered to the ceramic substrate along the perimeter of the cover.

8. The fuel level measurement device set forth in claim 6 further comprising a continuous solder trace of the ceramic substrate disposed along the perimeter of the cover for soldering the cover to the substrate.

9. The fuel level measurement device set forth in claim 6 further comprising a signal wire connected electrically to the resistive ink strip and extending through a hermetically sealed hole of the substrate.

10. The fuel level measurement device set forth in claim 6 wherein the ceramic substrate is substantially planar and the cover is contoured.

11. The fuel level measurement device set forth in claim 10 further comprising a concave track carried by the cover and the ceramic substrate, and substantially facing upward toward the top of the fuel tank.

12. The fuel level measurement device set forth in claim 1 wherein the first contact point is singular and is the only contact point between the variable resistive ink strip and the gravity responsive electrically conductive member.

13. A fuel level measurement device of a fuel pump module configured to be located in a fuel tank, the fuel level measurement device comprising:

a float that rotates about an axis of rotation with varying fuel level, the float having a housing defining a sealed chamber;

an electrically variable resistive ink strip carried by the housing and exposed in the chamber;

an electrically conductive portion of the housing substantially confronting the resistive ink strip; and

a conductive member constructed and arranged to maintain a low point by gravity with rotation of the float, the conductive member contacting the resistive ink strip at a movable first point and riding along the resistive ink strip as the float moves arcuately about an imaginary centerline with varying fuel level, and contacting the electrically conductive portion at a movable second point.

14. The fuel level measurement device set forth in claim 13 further comprising an arm pivotally carried by the fuel pump module and projecting longitudinally outward and attached to the housing to move in unison with the housing.

15. The fuel level measurement device set forth in claim 13 wherein the conductive member is a metallic ball.

16. The fuel level measurement device set forth in claim 13 wherein the resistive ink strip is carried by a ceramic substrate of the housing.

17. The fuel level measurement device set forth in claim 16 wherein the electrically conductive portion of the housing is a metallic cover hermetically sealed along a perimeter to the ceramic substrate.