Detecting spark in igniter of gas turbine engine by detecting signals in grounded RF shielding
AssigneeGeneral Electric Company
InventorsRobert L. 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 Inventors have found that this approach is effective, despite the fact that the inductor is surrounded by grounded shielding intended to suppress rf interference, and to protect personnel from high voltages present. The shielding is intended to block the very signals which the invention detects.
Claims18
In a gas turbine engine which includes (1) an igniter, (2) a cable running from an exciter to the igniter which delivers electrical power to the igniter, (3) a first conductive shield surrounding the cable and connected to the engine, and (4) a second conductive shield extending from the external conductive shield and surrounding the igniter, a method comprising:
- a) maintaining a sensor adjacent the igniter;
- b) detecting a current pulse in either the first or second conductive shields, or both;
- and
- c) issuing a signal indicating presence of spark when a current pulse is detected.
In a gas turbine engine which includes (1) an igniter, (2) a cable running from an exciter to the igniter which delivers electrical power to the igniter, (3) a first conductive shield surrounding the cable and connected to the engine, and (4) a second conductive shield extending from the external conductive shield and surrounding the igniter, apparatus comprising:
- a) a coil adjacent the igniter;
- b) means for detecting a current pulse in either the first or second conductive shield, or both;
- and
- c) means for issuing a signal indicating presence of spark when a current pulse is detected.
Apparatus for detecting spark, comprising:
- a) a power source which applies a high voltage to a conductor connected to a spark gap, to cause dielectric breakdown in the spark gap;
- b) a current path for carrying return current from the spark gap to the power source when breakdown occurs;
- c) a conductive shield around the conductor;
- and
- d) a detector for detecting current in the conductive shield, and issuing a signal indicating presence of spark in response.
Apparatus in a gas turbine engine, comprising:
- a) an igniter which is
- i) surrounded by a housing, and
- ii) fed by a power cable which is surrounded by a conductive shield which is connected to the housing;
- and
- b) a detector for
- i) detecting current in the shield, housing, or a combination thereof, but without contacting the cable, and,
- ii) in response, issuing a signal indicating presence of spark in the igniter.
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 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.