System and method for controlling fuel flow to a gas turbine engine

• US 20030192300A1
• Filed: 05/20/2003
• Published: 10/16/2003
• Est. Priority Date: 09/07/2001
• Status: Active Grant

• Current Assignee: David D. Jones, Timothy D. Mahoney
• Original Assignee: David D. Jones, Timothy D. Mahoney
• Inventors: Jones, David D., Mahoney, Timothy D.
• Granted Patent: US 6,751,942 B2
• Time in Patent Office: Days
• US Class Current: 60/39.281
• CPC Class Codes: F02C 9/263 by means of fuel metering valves
• CPC Class Codes: F02C 9/38 characterised by throttling and returning of fuel to sump
• CPC Class Codes: F05D 2270/094 by using back-up controls

Abstract

A system for controlling the flow of fuel to a gas turbine engine is operable in at least two modes. In a first mode, the flow rate of fuel supplied from a fuel source to the combustors of the turbine engine is controlled by modulating the position of a metering valve. A controller determines the controllability of the metering valve and, if it is determined to be non-controllable, then the system is operated in the second mode. In the second mode, the flow rate of fuel supplied to the combustors is controlled by modulating the position of a bypass valve.

Claims

1. A system for delivering fuel from a fuel source to a gas turbine engine combustor, comprising:

a fuel supply line having an inlet coupled to the fuel source and an outlet coupled to the combustor;

a metering valve positioned in flow-series in the supply line;

a bypass flow line coupled between an inlet of the metering valve and the fuel supply line inlet for bypassing a portion of the fuel in the supply line back to the inlet;

a bypass valve positioned in flow-series in the bypass flow line; and

a controller operable to selectively adjust one of the metering valve and the bypass valve to control fuel flow rate from the fuel source to the combustor.

2. The system of claim 1, wherein:

the metering valve includes a first variable area flow orifice; and

the controller, when operable to adjust the metering valve, supplies a first valve control signal to adjust the area of the first variable area flow orifice.

3. The system of claim 2, further comprising:

a metering valve control device coupled to the metering valve and to receive the first valve control signal, the metering valve control device operable, in response to the first valve control signal, to adjust the metering valve.

4. The system of claim 1, wherein:

the bypass valve includes a second variable area flow orifice; and

the controller, when operable to adjust the bypass valve, supplies a second valve control signal to adjust the area of the second variable area flow orifice.

5. The system of claim 4, further comprising:

a head sensor operably coupled between an inlet and an outlet of the metering valve for (i) sensing a differential pressure between the inlet and the outlet and (ii) adjusting the bypass valve to maintain a substantially constant predetermined differential pressure there between.

6. The system of claim 5, further comprising:

a bypass valve control device coupled to the head sensor and to receive the second valve control signal, the bypass valve control device operable, in response to the second valve control signal, to cause the head sensor to sense a predetermined differential pressure to thereby adjust the bypass valve.

7. The system of claim 6, wherein the bypass valve control device is not operable to cause the head sensor to sense a predetermined differential pressure when the controller is operable to adjust the metering valve.

8. The system of claim 1, wherein the controller is operable to:

determine whether the metering valve is controllable or non-controllable;

adjust the metering valve to control fuel flow to the combustor when the metering valve is determined to be controllable; and

adjust the bypass valve to control fuel flow to the combustor when the metering valve is determined to be non-controllable.

9. The system of claim 8, further comprising:

a position sensor operably coupled to the metering valve for sensing a position of the metering valve and supplying a metering valve position signal to the controller,

wherein the controller determines whether the metering valve is controllable or non-controllable by comparing the valve position signal and a commanded flow signal.

10. The system of claim 9, further comprising:

a flow sensor operably coupled to the fuel supply line for sensing flow rate of the fuel to the combustor and supplying a flow signal to the controller,

wherein the controller determines whether the metering valve is controllable or non-controllable by comparing the position signal and the flow signal.

11. The system of claim 8, further comprising:

a flow sensor operably coupled to the fuel supply line for sensing flow rate of the fuel to the combustor and supplying a flow signal to the controller,

wherein the controller determines whether the metering valve is controllable or non-controllable by comparing the flow signal and a commanded flow signal.

12. The system of claim 8, wherein the controller is operable to perform electrical checks of the position sensor and interconnecting wiring.

13. The system of claim 11, wherein the controller is operable to perform electrical checks of the flow sensor and interconnecting wiring.

14. A controller for controlling the flow rate of fuel from a pressurized fuel source to a gas turbine engine combustor via a metering valve, comprising:

a first valve driver circuit portion operable to generate a first valve driver signal;

a second valve driver circuit portion operable to generate a second valve driver signal;

at least one processor operable to determine whether the metering valve is controllable or non-controllable and, based on the determination, to enable one of the first and second valve driver circuits and disable the other.

15. The controller of claim 14, wherein the at least one processor is coupled to receive (i) a first signal representative of actual fuel flow rate to the combustor and (ii) a command signal representative of a commanded fuel flow rate to the combustor, and is operable to compare the first signal and the command signal and, based on the comparison, enable one of the first and second valve driver circuits and disable the other.

16. The controller of claim 15, wherein the at least one processor enables the first valve driver circuit and disables the second valve driver circuit when the flow signal and the command signal are substantially equal.

17. The controller of claim 15, wherein the at least one processor enables the second valve driver circuit and disables the first valve driver circuit when the flow signal and the command signal are substantially unequal.

18. The controller of claim 14, further comprising:

a manual input device operably coupled to the controller for supplying a valve adjustment signal to the second valve driver.

19. The controller of claim 14, wherein the second valve driver circuit is physically separate from the first valve driver circuit.