Glow plug with pressure sensing canister
AssigneeFederal-Mogul Italy Srl
InventorsJohn A. Burrows, Sandro Goretti
Life of this patent
Estimating the term…
Abstract
A glow plug assembly includes an integrated, internal pressure sensor. In order to reduce loading on the center electrode, improve sensor responsiveness, and provide better thermal performance, the pressure sensor assembly is housed in a canister which forms a containment capsule and rigidly connects inside the glow plug shell near its seat area. The pressure sensor makes direct contact with the base end of the heater probe so that movements of the heater probe caused by fluctuations in gas pressure lead directly to changing force on the sensor stack.
Claims22
A glow plug assembly for an internal combustion engine and having an integrated internal pressure sensor, said assembly comprising:
- a shell having an axially extending bore;
- an elongated heater probe having a base end disposed within said bore in electrical contact with said shell;
- an electrode in electrical contact with said base end of said heater probe while being electrically insulated from said shell;
- a pressure sensor disposed within said shell, said pressure sensor supported on one side thereof against said base end of said heater probe and adapted to measure pressure fluctuations when said glow plug assembly is installed in an engine;
- and a canister disposed within said shell and surrounding said pressure sensor, said canister extending between first and second ends thereof with said first end operatively fixed to said shell and said second end in pressing contact with said pressure sensor for establishing a compressive preload force on said pressure sensor without transmitting transient distortions occurring in said shell to said pressure sensor.
A method for manufacturing a glow plug assembly of the type having an integrated internal pressure sensor, said method comprising the steps of:
- forming a shell having an axially extending bore;
- forming an elongated heater probe having a base end and a heating tip opposite the base end;
- supporting the base end of the heater probe within the bore of the shell so as to establish electrical conductivity between the shell and the heater probe;
- electrically connecting an electrode to the base end of the heater probe while maintaining electrical insulation between the electrode and the shell;
- providing a canister having first and second ends;
- attaching the first end of the canister to the shell;
- providing a pressure sensor;
- placing the pressure sensor inside the canister so that the pressure sensor rests against the base end of the heater probe;
- and
- compressing the pressure sensor with the second end of the canister to establish a preload force on the pressure sensor.
Dependencies are inferred from the claim text.