Aircraft hydraulic thermal management system

Patent metadata

Field	Value
Publication number	US-9920779-B2
Application number	US-201514816818-A
Country	US
Kind code	B2
Filing date	Aug 3, 2015
Priority date	Aug 3, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

An aircraft hydraulic thermal management system utilizes fuel to cool hydraulic fluid by means of a heat exchanger. A hydraulic pump includes a case drain flow of hydraulic fluid at a first temperature to drive a hydraulic motor; the hydraulic motor circulates hydraulic fluid to a reservoir at a second temperature. The heat exchanger is positioned remotely of the fuel tank, and has first and second channels positioned in thermal communication to transfer heat from the hydraulic fluid to the fuel. The hydraulic motor is mechanically coupled to the fuel pump; the hydraulic motor, driven by case drain flow through the first channel, thus operates the fuel pump to move fuel through the second channel. The thermal management system is configured to assure that a) the hydraulic pump circulates hydraulic fluid to the reservoir at the second temperature, and b) the second temperature is always lower than the first temperature.

First claim

What is claimed is:

1. An aircraft hydraulic thermal management system, comprising:
a hydraulic pump including a case drain flow of hydraulic fluid at a first temperature;
a hydraulic motor, a reservoir of hydraulic fluid, and a hydraulic bypass valve, wherein the hydraulic pump draws the hydraulic fluid from the reservoir, and wherein the case drain flow drives the hydraulic motor;
a fuel tank;
a fuel pump configured to circulate fuel from the fuel tank, and then to transfer the fuel back into the fuel tank at a second temperature;
a heat exchanger having first and second channels, the first configured to receive the hydraulic fluid via the hydraulic motor, and the second configured to receive the fuel, the heat exchanger configured to transfer heat from the hydraulic fluid to the fuel, the heat exchanger being positioned remotely of the fuel tank;
wherein the hydraulic motor is positioned upstream of the heat exchanger and downstream of the bypass valve; and
wherein the thermal management system is configured to assure that a) the fuel pump circulates the fuel into the fuel tank at the second temperature, and b) the second temperature is always lower than the first temperature.

2. The aircraft hydraulic thermal management system of claim 1 ,
wherein the bypass valve is disposed between the hydraulic pump and the hydraulic motor, and is configured to channel the case drain flow into the reservoir in a first operational mode, and to channel the case drain flow to the hydraulic motor in a second operational mode.

3. The aircraft hydraulic thermal management system of claim 2 , wherein the fuel pump is disposed between the fuel tank and the heat exchanger, and wherein the fuel pump is driven by the hydraulic motor.

4. The aircraft hydraulic thermal management system of claim 3 , wherein the fuel pump is mechanically coupled to hydraulic motor.

5. The aircraft hydraulic thermal management system of claim 1 , wherein the hydraulic bypass valve comprises a thermal actuator and a valve spool, and wherein the thermal actuator is coupled to the valve spool, and wherein the valve spool is configured to shift the hydraulic bypass valve from a first position corresponding to the first operational mode to a second position corresponding to the second operational mode, as a function of temperature of the hydraulic fluid.

6. The aircraft hydraulic thermal management system of claim 5 , wherein the hydraulic motor is interposed between the hydraulic bypass valve and the first channel of the heat exchanger.

7. The aircraft hydraulic thermal management system of claim 1 , wherein the fuel pump is a secondary fuel pump dedicated to circulation of fuel through the second channel of the heat exchanger.

8. The aircraft hydraulic thermal management system of claim 2 , wherein the first operational mode comprises direct movement of the case drain flow from the hydraulic pump to the reservoir.

9. The aircraft hydraulic thermal management system of claim 2 , wherein the second operational mode comprises movement of the case drain flow through the hydraulic motor and into the first channel of the heat exchanger before return of the hydraulic fluid to the reservoir.

10. An aircraft, comprising:
a hydraulic thermal management system including a hydraulic pump having a case drain flow, a hydraulic motor driven by the case drain flow from the hydraulic pump, and a reservoir of hydraulic fluid, the hydraulic pump drawing hydraulic fluid from the reservoir; the thermal management system having the case drain flow of hydraulic fluid at a first temperature; a fuel tank; a fuel pump configured to circulate fuel from the fuel pump at a second temperature and then to transfer the fuel into the fuel tank; a heat exchanger having first and second channels configured to receive the hydraulic fluid and the fuel, respectively, and to transfer heat from the hydraulic fluid to the fuel, the heat exchanger being positioned remotely of the fuel tank; wherein the hydraulic motor is positioned upstream of the heat exchanger; and wherein the thermal management system is configured to assure that a) the fuel pump circulates the fuel from the fuel pump at the second temperature, and b) the second temperature is always lower than the first temperature.

11. The aircraft of claim 10 , wherein the hydraulic thermal management system further comprises a
bypass valve disposed between the hydraulic pump and the hydraulic motor, and is configured to channel the case drain flow into the reservoir in a first operational mode, and to channel the case drain flow to the hydraulic motor in a second operational mode.

12. The aircraft of claim 11 , wherein the fuel pump is disposed between the fuel tank and the heat exchanger, and wherein the fuel pump is driven by the hydraulic motor.

13. The aircraft of claim 12 , wherein the fuel pump is mechanically coupled to hydraulic motor.

14. The aircraft of claim 10 , wherein the hydraulic bypass valve comprises a thermal actuator and a valve spool, and wherein the thermal actuator is coupled to the valve spool, and wherein the valve spool is configured to shift the hydraulic bypass valve from a first position corresponding to the first operational mode to a second position corresponding to the second operational mode, as a function of temperature of the hydraulic fluid.

15. The aircraft of claim 14 , wherein the hydraulic motor is interposed between the hydraulic bypass valve and the first channel of the heat exchanger.

16. The aircraft of claim 10 , wherein the fuel pump is a secondary fuel pump dedicated to circulation of fuel through the second channel of the heat exchanger.

17. The aircraft of claim 11 , wherein the first operational mode comprises direct movement of the case drain flow to the reservoir.

18. The aircraft of claim 11 , wherein the second operational mode comprises movement of the case drain flow through the hydraulic motor and into the first channel of the heat exchanger before return of the case drain flow to the reservoir.

19. A method of making an aircraft hydraulic thermal management system, comprising the steps of:
configuring a hydraulic pump and a hydraulic motor to have a case drain flow of hydraulic fluid at a first temperature;
securing a fuel tank and a fuel pump to the hydraulic thermal management system;
configuring the fuel pump to circulate fuel from the fuel tank, and then to transfer the fuel back into the fuel tank at a second temperature;
securing a heat exchanger to the hydraulic thermal management system, and configuring first and second channels in the heat exchanger to receive the hydraulic fluid and the fuel, respectively, and to transfer heat from the hydraulic fluid to the fuel;
locating the heat exchanger remotely of the fuel tank;
locating the hydraulic motor upstream of the heat exchanger; and
configuring the thermal management system to assure that a) the fuel pump circulates the fuel into the fuel tank at the second temperature, and b) the second temperature is always lower than the first temperature.

20. The method of claim 19 , further comprising the steps of:
securing a hydraulic reservoir, the hydraulic motor, and a hydraulic bypass valve to the hydraulic thermal management system, and configuring the hydraulic pump to include a case drain flow to drive the hydraulic motor; configuring the fuel pump to be driven by the hydraulic motor; and
placing the bypass valve between the hydraulic pump and the hydraulic motor, and configuring a first operational mode to channel the c

Assignees

• Boeing Co

Inventors

• Liao Jianmin

Classifications

• F15B2211/7058

  Rotary output members · CPC title

• B64D37/34 Primary

  Conditioning fuel, e.g. heating (during filling B64D37/18) · CPC title

• F15B2211/611

  Diverting circuits, e.g. for cooling or filtering · CPC title

• F01P7/00

  Controlling of coolant flow · CPC title

• B23P19/04

  for assembling or disassembling parts · CPC title