Fuel flow estimation and control system and method in a gas turbine engine

Patent metadata

Field	Value
Publication number	US-2016245188-A1
Application number	US-201514626631-A
Country	US
Kind code	A1
Filing date	Feb 19, 2015
Priority date	Feb 19, 2015
Publication date	Aug 25, 2016
Grant date	—

Abstract

A system and methods of estimating and controlling fuel flow in a gas turbine engine are disclosed. The system and methods include providing a metering valve and a pressure regulating valve. The system and methods further include determining a differential pressure error of the pressure regulating valve based on a metering valve inlet pressure, a discharge pressure, and a bypass fuel flow and determining a metering valve fuel flow based on a metering valve position and the differential pressure error.

First claim

What is claimed is:

1 . A method of estimating fuel flow in a gas turbine engine including a metering valve in fluid communication with a bypass fuel line and a pressure regulating valve, the method comprising:
determining a metering valve position; determining a bypass fuel flow; determining a metering valve inlet pressure; determining a discharge pressure upstream of the bypass fuel line; determining a differential pressure error of the pressure regulating valve based on the metering valve inlet pressure, the discharge pressure, and the bypass fuel flow; determining a metering valve fuel flow based on the metering valve position and the differential pressure error; and controlling the metering valve based on the metering valve fuel flow.

2 . The method of claim 1 , wherein determining the bypass fuel flow is based on an actuation system leakage fuel flow, a corrected metering valve fuel flow, and a pump fuel flow.

3 . The method of claim 1 , wherein determining the metering valve inlet pressure is based on a pressure downstream of the metering valve and an ideal pressure regulating valve differential pressure.

4 . The method of claim 3 , wherein the pressure downstream of the metering valve is based on a mass flow meter differential pressure, a minimum pressure shut off valve differential pressure, and a flow divider valve inlet pressure.

5 . The method of claim 1 , wherein determining the differential pressure error is further based on an ideal pressure regulating valve differential pressure.

6 . The method of claim 1 , further comprising determining an uncorrected fuel flow based on the metering valve position and an ideal stroke-to-flow map, wherein determining the metering valve fuel flow is based on the uncorrected fuel flow and the differential pressure error.

7 . The method of claim 1 , further comprising determining a fuel density, wherein determining the metering valve fuel flow is further based on the fuel density.

8 . The method of claim 1 , wherein determining the differential pressure error is based on a pressure regulating valve differential pressure map.

9 . A method of controlling fuel flow in a gas turbine engine, comprising:
receiving a requested fuel flow; determining a differential pressure error; determining a corrected fuel flow based on the requested fuel flow and the differential pressure error; determining a requested metering valve position based on the corrected fuel flow; and controlling a metering valve based on the requested metering valve position.

10 . The method of claim 9 , wherein determining the requested metering valve position is further based on an ideal flow-to-stroke map.

11 . The method of claim 9 , further comprising determining a density corrected fuel flow based on the requested fuel flow and a fuel density error.

12 . The method of claim 9 , further comprising correcting the requested metering valve position based on an uncorrected metering valve position and a position error value.

13 . A fuel flow estimation system in a gas turbine engine comprising:
a metering valve; a pressure regulating valve configured to regulate pressure across the metering valve; a bypass fuel line in fluid communication with the pressure regulating valve; a discharge fuel line upstream of the bypass fuel line; and a controller configured to:
determine a differential pressure error of the pressure regulating valve based on a bypass fuel flow of the bypass fuel line, an inlet pressure of the metering valve, and a discharge pressure of the discharge fuel line; and
determine a metering valve fuel flow based on the differential pressure error and a position of the metering valve.

14 . The system of claim 13 , further comprising:
a fuel pump; a fuel nozzle; and an actuation system, wherein the bypass fuel flow is based on a fuel flow of the fuel pump, a corrected metering valve fuel flow, and an actuation system leakage fuel flow of the actuation system.

15 . The system of claim 13 , wherein the metering valve inlet pressure is based on a pressure downstream of the metering valve and an ideal pressure regulating valve differential pressure.

16 . The system of claim 15 , further comprising:
a mass flow meter positioned downstream of the metering valve; a minimum pressure shut off valve positioned downstream of the metering valve; and a flow divider valve positioned downstream of the metering valve, wherein a pressure downstream of the metering valve is based on a differential pressure of the mass flow meter, a differential pressure of the minimum pressure shut off valve, and an inlet pressure of the flow divider valve.

17 . The system of claim 13 , wherein the differential pressure error is based on an ideal pressure regulating valve differential pressure.

18 . The system of claim 13 , wherein the controller is further configured to
determine an uncorrected fuel flow based on the metering valve position and an ideal stroke-to-flow map; and determine the metering valve fuel flow based on the uncorrected fuel flow and the differential pressure error.

19 . The system of claim 13 , wherein the controller is further configured to
determine a fuel density; and determine the metering valve fuel flow based on the fuel density.

20 . The system of claim 13 , wherein the differential pressure error is based on a pressure regulating valve differential pressure map.

Assignees

• United Technologies Corp

Inventors

• Selstad Tyler J
• Haugsjaahabink Todd

Classifications

• G01F1/34

  by measuring pressure or differential pressure · CPC title

• F05D2220/32

  in gas turbines · CPC title

• G01F13/00

  Apparatus for measuring by volume and delivering fluids or fluent solid materials, not provided for in the preceding groups · CPC title

• F02C9/32 Primary

  characterised by throttling of fuel (F02C9/38 takes precedence) · CPC title

• F05D2260/821

  Parameter estimation or prediction · CPC title