Spark apparatus with pressure signal response amplification
AssigneeDelphi Technologies, Inc.
InventorsDean M. Ford, Diane E. Hageman, Ronald J. Kiess, Robert A. Noel
Life of this patent
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Abstract
An ignition coil, spark plug, and pressure sensor for an internal combustion engine are, in a preferred embodiment, integrated into a single assembly and mounted directly on a plug hole of an internal combustion engine. A hard spark plug shell serves as a pressure member and on which a strain gage is affixed. Changes in the pressure in the combustion chamber deform the shell, causing a corresponding change in the resistance of the strain gage. A bridge circuit or the like is used to measure the resistance change thereby providing a direct indication of cylinder pressure.
Claims23
A spark generating assembly configured to detect a pressure in a cylinder of an internal combustion engine, said assembly comprising:
- a central electrode having a main axis and a first end configured for connection to a voltage source, said central electrode further having a second, exposed end opposite said first end;
- an annular insulator outwardly of said central electrode, said insulator having an enlarged central body with a first annular shoulder and a second annular shoulder, wherein said insulator includes a third annular shoulder axially intermediate said first and second shoulders;
- an annular conductive shell having a central bore, said insulator being disposed in said central bore, said shell extending circumferentially and radially inwardly over said first annular shoulder of said insulator to form a first seal having a first spring rate, said shell further having an annular inner shoulder facing said central bore;
- a second seal having a second spring rate less than said first spring rate disposed between said second annular shoulder of said insulator and said inner shoulder of said shell, wherein said second seal comprises a Belleville washer arranged in a preloaded condition so as to exhibit said second spring rate, said washer having said second spring rate of about zero at a preselected preload force wherein further increases in said pressure in said cylinder above said preselected preload force will encounter reduced stiffness at said lower seal;
- a ground electrode spaced apart from said second end of said central electrode defining a spark gap therebetween, said ground electrode being electrically connected to said shell;
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- a transducer affixed to said shell.
An apparatus for initiating a spark in a cylinder in a combustion engine comprising:
- a central electrode having an axis and opposing first and second ends;
- an insulator outwardly of said central electrode;
- a conductive shell outwardly of said insulator and including a radially inwardly extending portion defining an upper seal having a first spring rate;
- a lower seal between said insulator and said shell having a second spring rate less than said first spring rate wherein said lower seal comprises a Belleville washer arranged in a preloaded condition so as to exhibit said second spring rate, said washer having said second spring rate of about zero at a preselected preload force wherein further increases in said pressure in said cylinder above said preselected preload force will encounter reduced stiffness at said lower seal;
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- a transducer in sensing relation to said shell configured to produce a signal indicative of a pressure in said cylinder.
A glow plug for a cylinder in a combustion engine comprising:
- a central electrode having an axis and opposing first and second ends;
- an insulator outwardly of said central electrode;
- a conductive shell outwardly of said insulator and including a radially inwardly extending portion defining an upper seal having a first spring rate;
- a lower seal between said insulator and said shell having a second spring rate less than said first spring rate wherein said lower seal comprises a Belleville washer arranged in a preloaded condition so as to exhibit said second spring rate, said washer having said second spring rate of about zero at a preselected preload force wherein further increases in said pressure in said cylinder above said preselected preload force will encounter reduced stiffness at said lower seal;
- and
- a transducer in sensing relation to said shell configured to produce a signal indicative of a pressure in said cylinder.
Dependencies are inferred from the claim text.