Fuel systems having thermal recirculation

Patent metadata

Field	Value
Publication number	US-11946420-B1
Application number	US-202318213053-A
Country	US
Kind code	B1
Filing date	Jun 22, 2023
Priority date	Jun 22, 2023
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

A fuel system includes a main pump assembly. The main pump assembly has a main fuel pump connected to an input line, a recirculation pump connected to the input line, and a fuel recirculation system. A recirculation control includes a first selector valve in fluid communication with an outlet line of the recirculation pump, with a recirculation return line connected to return fuel to the input line, and with an inter-valve line. The recirculation control includes a second selector valve in fluid communication with the inter-valve line, with a back-up line connecting the second selector valve to a main fuel control, and with a cooler recirculation line connected to supply the one or more coolers.

First claim

What is claimed is:

1. A fuel system, comprising:
a main pump assembly having:
a main fuel pump connected to an input line and configured to pump fuel to a main fuel control via a main fuel control line;
a recirculation pump connected to the input line;
a fuel recirculation system connected to an outlet line of the recirculation pump and upstream of the main fuel control, the fuel recirculation system configured to select a mode from a plurality of modes, wherein the plurality of modes include a recirculation mode and a backup mode, wherein the fuel recirculation system is configured to recirculate fuel from the recirculation pump to a tank through one or more coolers in the recirculation mode, and provide fuel to the main fuel control in the backup mode; and
a recirculation control configured to select between the recirculation mode and the backup mode, wherein the recirculation control includes:
a first selector valve in fluid communication with the outlet line of the recirculation pump, with a recirculation return line connected to return fuel to the input line, and with an inter-valve line, wherein the first selector valve is configured to select between connecting the outlet line of the recirculation pump with either the recirculation return line or with the inter-valve line; and
a second selector valve in fluid communication with the inter-valve line, with a back-up line connecting the second selector valve to the main fuel control, and with a cooler recirculation line connected to supply the one or more coolers, wherein the second selector valve is configured to select between connecting the inter-valve line with either the back-up line or with the cooler recirculation line.

2. The system of claim 1 , further comprising a check valve in the backup line configured to open to provide backup fuel flow to the main fuel control from the recirculation pump in the backup mode and to prevent back flow in the backup line otherwise.

3. The system of claim 1 , wherein the cooler recirculation line includes a pressure regulating valve configured to only allow flow through the cooler recirculation line above a predetermined pressure.

4. The system of claim 1 , wherein the second selector valve is passively controlled based on pressure in the backup line.

5. The system of claim 1 , wherein the recirculation control includes an electrohydraulic servo valve (EHSV) connected in fluid communication with the outlet line of the recirculation pump, with the recirculation return line, and with a control line connecting the EHSV in fluid communication with a control port of the first selector valve for control of the first selector valve.

6. The system of claim 1 , wherein the plurality of modes includes a bypass mode, wherein the fuel recirculation system is configured to bypass the one or more coolers in the bypass mode, wherein the recirculation control is configured to select between the recirculation mode, the backup mode, and the bypass mode.

7. The system of claim 1 , wherein the fuel recirculation system includes the one or more coolers in fluid communication with the recirculation control downstream of the recirculation control, and in fluid communication with the tank via a tank return line.

8. The system of claim 1 , further comprising the main fuel control connected to the main fuel control line of the main pump assembly and the backup line.

9. The system of claim 8 , further comprising an augmenter pump fuel control in fluid communication with the inlet line in parallel with the main fuel control, the main fuel pump, and the recirculation pump.

10. The system of claim 9 , further comprising an actuator pump fuel control in fluid communication with the inlet line in parallel with the augmenter pump fuel control.

11. The system of claim 10 , wherein the main fuel control, the augmenter pump fuel control, and the actuator pump fuel control are interconnected for mutual backup.

12. The system of claim 1 , further comprising a filter in the input line upstream of the main pump and of the recirculation pump.

13. The system of claim 1 , wherein the recirculation return line is connected in fluid communication to return fluid to the input line upstream of the filter in the bypass mode.

14. The system of claim 1 , wherein the main fuel pump and the recirculation pump are positive displacement pumps.

15. The system of claim 14 , wherein the positive displacement pumps are vane pumps.

16. The system of claim 14 , wherein the positive displacement pumps are gear pumps.

17. The system of claim 14 , further comprising a boost pump with an boost inlet connected to a tank line to supply the boost pump from the tank, wherein an outlet of the boost pump is connected to supply the input line.

18. The system of claim 17 , wherein the boost pump, and at least one of the positive displacement pumps are connected to rotate together on a single shaft.

19. The system of claim 17 , further comprising the tank connected in fluid communication to supply the boost pump, wherein the tank is a fuel tank.

20. The system of claim 19 , wherein the tank is connected to receive cooled fuel from the one or more coolers.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Goy Edward W
• Susca Ryan Prescott
• Shook Ryan

Classifications

• F02C7/236 Primary

  Fuel delivery systems comprising two or more pumps · CPC title

• F02C7/14 Primary

  of fluids in the plant {, e.g. lubricant or fuel (F02C7/185 takes precedence)} · CPC title

• F02C7/222

  Fuel flow conduits, e.g. manifolds · CPC title

• F02C7/232

  Fuel valves {(control of fuel supply by means of fuel metering valves F02C9/263)}; Draining valves or systems (valves in general F16K) · CPC title

• F02C9/32

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