Passive, high-temperature amplifier for amplifying spark signals detected in igniter in gas turbine engine
AssigneeGeneral Electric Company
InventorsRobert Ponziani, Roy Earwood
Life of this patent
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Abstract
A system for detecting spark in an igniter for a gas turbine engine. An igniter generates a plasma, or spark, somewhat similar to an automotive spark plug. In the invention, an inductive pick-up is positioned adjacent the igniter, to detect current pulses in the igniter, to thereby infer the presence of spark. The signal produced is small, and requires amplification. However, the environment is hot, often exceeding 400 degrees F. The invention utilizes an amplifier composed of passive components, in the form of an RLC circuit.
Claims15
A method of detecting spark in an igniter in a gas turbine engine, comprising:
- a) providing a transformer having
- i) a primary which carries igniter current and
- ii) a secondary of inductance L;
- b) connecting the secondary in series with a resistance R and capacitance C;
- and
- c) inferring presence of spark by detecting signals in capacitance C.
A method of detecting spark in an igniter in a gas turbine engine, comprising:
- a) providing a transformer having
- i) a primary which carries igniter current and
- ii) a secondary of inductance L;
- b) connecting the secondary in series with a resistance R and capacitance C;
- and
- c) inferring presence of spark by detecting signals in capacitance C,
- wherein a cable connects to the igniter, the cable and the igniter are surrounded by an conductive electrical shield connected to an engine frame, and the secondary comprises a coil wrapped around part of the shield, wherein the core of the coil comprises said part.
Apparatus, comprising:
- a) an igniter which is effective to reliably ignite fuel in a gas turbine engine;
- b) a coil adjacent a housing of the igniter, which produces signals when sparks are generated in the igniter.
Apparatus for detecting spark in an igniter in a gas turbine engine, comprising:
- a) a transformer having
- i) a primary which carries igniter current and
- ii) a secondary of inductance L;
- b) a resistance R and capacitance C in series with the inductance L;
- and
- c) a detector for inferring spark by detecting signals in capacitance C.
Apparatus for detecting spark in an igniter in a gas turbine engine, comprising:
- a) a transformer having
- i) a primary which carries igniter current and
- ii) a secondary of inductance L;
- b) a resistance R and capacitance C in series with the inductance L;
- and
- c) a detector for inferring spark by detecting signals in capacitance C,
- wherein a cable connects to the igniter, the cable and the igniter are surrounded by an conductive electrical shield connected to an engine frame, and the secondary comprises a coil wrapped around part of the shield, wherein the core of the coil comprises said part.
Apparatus, comprising:
- a) a gas turbine engine having a frame or casing having
- a potential defined as DC ground;
- b) an igniter in the engine;
- c) a supply cable which supplies current pulses to the igniter;
- d) a conductive shield around the supply cable, which connects to a housing of the igniter, wherein the shield and the housing are connected to said ground potential;
- e) an exciter which provides said current to the igniter, and which receives return current from the igniter through
- i) said shield, and
- ii) a second path;
- f) a detector comprising a coil and adjacent said housing, which detects one or more of the following:
- i) current pulses in the cable;
- ii) current pulses in the housing;
- or
- iii) differential between current pulses in the cable and current pulses in the housing.
Dependencies are inferred from the claim text.