Non-intrusive cylinder pressure sensor

• US 5,329,809 A
• Filed: 04/22/1993
• Issued: 07/19/1994
• Est. Priority Date: 04/22/1993
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Rodondi, Andrew F., Sellnau, Mark C., Plyler, Robert G.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Dombroske, George M.
• Application Number:
  US08/050,796
• Time in Patent Office: 453 Days
• Field of Search: 73/35, 73/115, 73/116, 73/117.3, 123/494, 123/425, 123/435
• US Class Current: 73/115.02
• CPC Class Codes: G01L 23/10 by pressure-sensitive members of the piezoelectric type

Abstract

A cylinder pressure sensor of the annular insert type disposed within an access well to measure the flexure of a first wall relative to a second wall along a response axis has low-cost components thereof requiring only simple sequential assembly in axial stacked fashion providing contaminant protection and electrical shielding of the sensing element.

Claims

1. In an internal combustion engine, a cylinder pressure sensor disposed between a first wall and a second wall of an engine component housing and axially responsive to flexure of the first wall relative to the second wall, comprising in combination:

a substantially cylindrical sleeve with a terminal end thereof being outwardly upwardly cupped to define an annular channel, the annular channel having a bottom portion thereof substantially normal to the sleeve for engagement with the first wall;

an annular load sensing element disposed within the annular channel;

a substantially cylindrical mounting shell having a lower portion nested within said annular channel and in communication with the sensing element, an upper portion for engagement with the second wall, and an axial conduit therethrough;

a substantially cylindrical annular bonnet having a top portion and a finger depending axially therefrom, the annular bonnet top portion being stacked adjacent the mounting shell with the finger disposed within the axial conduit thereby providing a carrier for electrically conductive material to a terminal at the distal end of the finger; and

means for sealing the sensing element from contamination.

2. A sensor according to claim 1 further comprising a compressibly yieldable contact for electrically coupling the sensing element and the electrically conductive material.

3. A sensor according to claim 2 wherein the yieldable contact comprises the terminal at the distal end of the finger.

4. A sensor according to claim 1 wherein the axial conduit is a groove open toward the interior of the mounting shell.

5. A sensor according to claim 1 further comprising an electrically conductive pattern disposed on the annular bonnet, the pattern having a runner portion coupled to the terminal and disposed axially on an inner surface of the finger and continuing axially along an inner surface of the top portion of the annular bonnet, and a terminal portion on an outer surface of the annular bonnet to define a cylindrical contact.

6. A sensor according to claim 5 wherein said inner surfaces of the annular bonnet are recessed thereby providing a gap between said electrically conductive pattern and any surfaces adjacent thereto.

7. A sensor according to claim 1 wherein the means for sealing the sensing element comprises a perimeter weld engaging the mounting shell to the terminal end of the cylindrical sleeve.

8. A sensor according to claim 1 wherein the means for sealing the sensing element comprises a perimeter weld engaging the mounting shell to the terminal end of the cylindrical sleeve and first and second O-rings, said first O-ring disposed between the mounting shell and annular bonnet, and said second O-ring disposed between the substantially cylindrical shell and the annular bonnet.

9. A sensor according to claim 1 wherein the annular bonnet further comprises an insulative carrier for sensor electronics.

10. In an internal combustion engine cylinder pressure sensor of the type having an annular insert and annular load sensing element, said sensor being disposed within an access well defined at least in part by an annular wall spanning a first wall and a second wall of an engine component housing and axially responsive to flexure of the first wall relative to the second wall, the improvement comprising:

said annular insert having an axially progressive assembly of components, said components including;

an electrically conductive annular sleeve with a terminal end thereof being outwardly upwardly cupped to define an annular channel,

an electrically conductive washer disposed within the annular channel,

an annular piezoceramic load sensing element disposed within the annular channel atop the load washer,

an electrically insulative washer disposed within the annular channel atop the piezoelectric load sensing element,

an annular mounting shell having an inner surface sized for proximally surrounding a portion of the annular sleeve, an upper portion for threadable engagement to said second wall and a lower portion disposed within the annular channel atop the insulative washer, the annular mounting shell further having an axial conduit from the upper portion to the lower portion thereof for electrical access to the sensing element,

an electrically insulative annular bonnet having an inner surface sized for proximally surrounding a portion of the annular sleeve, an axial finger depending therefrom and disposed within the axial conduit to provide a carrier for electrically conductive material, the finger having an electrical contact at its distal end for compressive coupling to the sensing element, and

means for axially and radially securing the annular mounting shell to the annular sleeve.