System and method for starting a gas turbine engine with inoperable exhaust gas turbine temperature sensor

• US 8,321,120 B2
• Filed: 01/16/2009
• Issued: 11/27/2012
• Est. Priority Date: 01/16/2009
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Riley, Harold
• Primary Examiner(s): Cheung, Mary
• Assistant Examiner(s): Do, Truc M
• Application Number:
  US12/355,395
• Publication Number:
  US 20100185377A1
• Time in Patent Office: 1,411 Days
• Field of Search: 701/100, 607/78
• US Class Current: 701/100
• CPC Class Codes: F01D 21/12 responsive to temperature
• CPC Class Codes: F01D 21/14 responsive to other specific conditions
• CPC Class Codes: F02C 7/26 Starting; Ignition
• CPC Class Codes: F05D 2270/09 to cope with emergencies
• CPC Class Codes: F05D 2270/095 by temporary overriding set control limits

Abstract

A system and method are provided for controlling the start-up of a gas turbine engine having an exhaust gas temperature (EGT) sensor. A determination is made as to whether the EGT sensor is available or unavailable. The gas turbine engine is commanded to accelerate at a nominal acceleration rate during the start-up operation if the EGT sensor is available, and to accelerate at an off-nominal acceleration rate during the start-up operation if the EGT sensor is unavailable. The off-nominal acceleration rate is lower than the nominal acceleration rate.

Claims

1. A gas turbine engine system, comprising:

a gas turbine engine adapted to receive fuel and air and configured to (i) controllably combust a mixture of the fuel and the air and (ii) discharge at least a portion of the combusted fuel air mixture as exhaust gas;

an exhaust gas temperature (EGT) sensor configured to sense exhaust gas temperature and supply an EGT sensor signal representative thereof; and

a controller configured to implement a plurality of speed-referenced acceleration rate schedules, the controller coupled to receive the EGT sensor signal and operable to;

(i) determine whether the EGT sensor signal is available or unavailable,

(ii) command a nominal acceleration rate of the gas turbine engine during a start-up operation of the gas turbine engine if the EGT sensor signal is available, and

(iii) command an off-nominal acceleration rate of the gas turbine engine during a start-up operation of the gas turbine engine if the EGT sensor signal is unavailable, wherein the off-nominal acceleration rate is lower than the nominal acceleration rate,

wherein the acceleration rate that the controller commands is supplied from one of the speed-referenced acceleration rate schedules.

2. The gas turbine engine system of claim 1, wherein:

each speed-referenced acceleration rate schedule supplies an acceleration rate; and

the controller determines which of the supplied acceleration rates is lowest;

the acceleration rate that the controller commands is the lowest.

3. The gas turbine engine system of claim 1, wherein:

the controller is adapted to receive a plurality of external sensor signals, each external sensor signal representative of a sensed parameter that is external of the gas turbine engine;

the controller has stored therein a plurality of default values, each default value corresponding to one of the sensed parameters;

the acceleration rate supplied from each speed-referenced acceleration rate schedule is based on an associated one of the sensed parameters;

each speed-referenced acceleration rate schedule uses the external sensor signal representative of its associated sensed parameter if the EGT sensor signal is available; and

the speed-referenced acceleration rate schedule uses the default value that corresponds to its associated sensed parameter if the EGT sensor signal is unavailable.

4. The gas turbine engine system of claim 3, wherein the plurality of external sensor signals comprise:

a lubricant temperature sensor signal representative of lubricant temperature;

an ambient pressure sensor signal representative of ambient pressure; and

an ambient temperature sensor signal representative of ambient temperature.

5. The gas turbine engine system of claim 1, wherein the controller implements light-off determination logic that enables the controller to command the off-nominal acceleration rate when the EGT sensor signal is unavailable.

6. The gas turbine engine system of claim 5, wherein the light-off determination logic:

is adapted to receive a fuel command signal indicating that a fuel supply command is being generated; and

enables the controller to command the off-nominal acceleration rate when the EGT sensor signal is unavailable only if the fuel supply command is generated for a predetermined time period.

7. The gas turbine engine system of claim 5, wherein the light-off determination logic:

is adapted to receive a speed signal representative of gas turbine rotational speed and a fuel command signal indicating that a fuel supply command is being generated; and

enables the controller to command the off-nominal acceleration rate when the EGT sensor signal is unavailable only if (i) the gas turbine rotational speed exceeds a predetermined speed and (ii) the fuel supply command is generated for a predetermined time period.

8. An engine controller for a gas turbine engine having an exhaust gas temperature (EGT) sensor, the engine controller comprising:

light-off logic operable to selectively supply an enable signal; and

acceleration command logic coupled to receive the enable signal from the light-off logic and adapted to receive an EGT loss signal whenever a sensor signal from the EGT sensor is unavailable, the acceleration command logic operable, upon receipt of the enable signal, to supply acceleration rate commands,

wherein;

the acceleration rate commands are nominal acceleration rate commands if the EGT loss signal is not received,

the acceleration rate commands are off-nominal acceleration rate commands if the EGT loss signal is received,

for equivalent conditions, the off-nominal acceleration rate commands are lower than the nominal acceleration rate commands,

the acceleration command logic includes a plurality of speed-referenced acceleration rate schedules, and

the acceleration rate commands are supplied from one of the speed-referenced acceleration rate schedules.

9. The engine controller of claim 8, wherein:

each speed-referenced acceleration rate schedule supplies acceleration rates; and

the acceleration command logic further includes selection logic that determines which of the supplied acceleration rates are lowest and supplies the lowest acceleration rates as the acceleration commands.

10. The engine controller of claim 8, wherein:

the acceleration command logic is further adapted to receive a plurality of external sensor signals, each external sensor signal representative of a sensed parameter that is external of a gas turbine engine;

the acceleration command logic is adapted to receive a plurality of stored default values, each default value corresponding to one of the sensed parameters;

the acceleration rate supplied from each speed-referenced acceleration rate schedule is based on an associated one of the sensed parameters;

each speed-referenced acceleration rate schedule uses the external sensor signal representative of its associated sensed parameter if the EGT loss signal is not present; and

each speed-referenced acceleration rate schedule uses the default value that corresponds to its associated sensed parameter if the EGT loss signal is present.

11. The engine controller of claim 10, wherein the plurality of external sensor signals comprises:

a lubricant temperature sensor signal representative of lubricant temperature;

an ambient pressure sensor signal representative of ambient pressure; and

an ambient temperature sensor signal representative of ambient temperature.

12. The engine controller of claim 8, wherein the light-off determination logic is adapted to receive the EGT loss signal and a fuel command signal indicating that a fuel supply command is being generated, the light-off determination logic operable to supply the enable signal to the acceleration command logic when the EGT loss signal is present only if the fuel supply command is generated for a predetermined time period.

13. The engine controller of claim 11, wherein the light-off determination logic is adapted to receive the EGT loss signal, a speed signal representative of gas turbine rotational speed, and a fuel command signal indicating that a fuel supply command is being generated, the light-off determination logic operable to supply the enable signal to the acceleration command logic when the EGT loss signal is present only if (i) the gas turbine rotational speed exceeds a predetermined speed and (ii) the fuel supply command is generated for a predetermined time period.

14. A method of controlling a gas turbine engine during a start-up operation, for a gas turbine engine having an exhaust gas temperature (EGT) sensor, the method comprising the steps of:

determining whether the EGT sensor is available or unavailable;

commanding the gas turbine engine to accelerate at a nominal acceleration rate during the start-up operation, if the EGT sensor is available, and

commanding the gas turbine engine to accelerate at an off-nominal acceleration rate during the start-up operation if the EGT sensor is unavailable, wherein the off-nominal acceleration rate is lower than the nominal acceleration rate;

wherein the acceleration rate that is commanded is supplied from one of a plurality of speed-referenced acceleration rate schedules.

15. The method of claim 14, wherein acceleration rates supplied from the speed-referenced acceleration rate schedules are based on a parameter that is external of the gas turbine engine, and wherein the method further comprises:

sensing the parameter and supply an external sensor signal representative thereof;

storing a default value of the sensed parameter;

basing the acceleration rates supplied from the speed-referenced acceleration rate schedules on the external sensor signal if the EGT sensor is available; and

basing the acceleration rates supplied from the speed-referenced acceleration rate schedule on the default value of the sensed parameter if the EGT sensor is unavailable.