Oil cooling system for aircraft engine

Patent metadata

Field	Value
Publication number	US-11591964-B2
Application number	US-202117350250-A
Country	US
Kind code	B2
Filing date	Jun 17, 2021
Priority date	Jun 17, 2021
Publication date	Feb 28, 2023
Grant date	Feb 28, 2023

Abstract

An oil cooling system for an aircraft engine, a bypass valve and an associate method of cooling aircraft engine oil are provided. The oil cooling system includes a heat exchanger having an inlet and an outlet. The inlet is in fluid communication with a first oil conduit to receive a first oil flow from the first oil conduit. The heat exchanger facilitates heat transfer from the first oil flow to another fluid. A flow restrictor defining a constriction is operatively disposed to restrict the first oil flow through the heat exchanger. A second oil conduit receives the first oil flow from the heat exchanger. A bypass oil passage provides fluid communication between the first oil conduit and the second oil conduit to allow a second oil flow received from the first oil conduit to flow to the second oil conduit and bypass the heat exchanger.

First claim

The invention claimed is:

1. An oil cooling system for an aircraft engine, the oil cooling system comprising:
a first oil conduit;
a heat exchanger having an inlet and an outlet, the inlet being in fluid communication with the first oil conduit to receive a first oil flow from the first oil conduit, the heat exchanger facilitating heat transfer from the first oil flow to a first fluid;
a flow restrictor defining a constriction and being operatively disposed to restrict the first oil flow through the heat exchanger, the flow restrictor being disposed inside a passage, the flow restrictor defining a reduction of at least 50% in flow-receiving cross-sectional area relative to the passage, the flow restrictor being sized to not substantially increase a pressure differential across the flow restrictor when oil of the first oil flow is at a nominal temperature corresponding to a cruise operating condition of the aircraft engine;
a second oil conduit in fluid communication with the outlet of the heat exchanger to receive the first oil flow from the heat exchanger;
a bypass providing fluid communication between the first oil conduit and the second oil conduit to allow a second oil flow received from the first oil conduit to bypass the heat exchanger and flow to the second oil conduit; and
a valve controlling an oil flow split between the heat exchanger and the bypass, the valve being configurable:
in an open configuration in which the bypass is open and the first oil flow is permitted through the heat exchanger and through the flow restrictor; and
in a closed configuration in which the bypass is closed and the first oil flow is permitted through the heat exchanger and through the flow restrictor.

2. The oil cooling system as defined in claim 1 , wherein:
the heat exchanger is a first heat exchanger facilitating heat transfer from the first oil flow to air; and
the oil cooling system includes a second heat exchanger downstream of the first heat exchanger to facilitate heat transfer from oil received from the second oil conduit to fuel.

3. The oil cooling system as defined in claim 1 , wherein the valve is a thermostatic valve.

4. The oil cooling system as defined in claim 1 , wherein the valve includes a valve body defining the passage establishing fluid communication between the first oil conduit and the inlet of the heat exchanger.

5. The oil cooling system as defined in claim 4 , wherein the flow restrictor includes a perforated body installed inside the passage.

6. The oil cooling system as defined in claim 1 , wherein the valve includes a valve body defining a passage establishing fluid communication between the outlet of the heat exchanger and the second oil conduit.

7. The oil cooling system as defined in claim 6 , wherein the flow restrictor includes a perforated body installed inside the passage.

8. The oil cooling system as defined in claim 1 , wherein the flow restrictor includes a perforated body installed inside the passage.

9. The oil cooling system as defined in claim 1 , wherein:
the passage is defined in a valve body; and
the flow restrictor is piece separate from the valve body that is inserted inside the passage.

10. A bypass valve for an oil cooling system of an aircraft engine, the bypass valve comprising:
a valve body defining:
a first oil passage extending from a first inlet to a first outlet,
a second oil passage extending from a second inlet to a second outlet, and
a bypass oil passage fluidly connecting the first oil passage to the second oil passage;

a valve member operable to control oil flow through the bypass oil passage; and
a flow restrictor defining a constriction and disposed inside the valve body either:
inside the first oil passage downstream of the bypass oil passage relative to the first inlet and the first outlet; or
inside the second oil passage upstream of the bypass oil passage relative to the second inlet and the second outlet,

wherein the flow restrictor is sized to not substantially increase a pressure differential across the flow restrictor when the oil is at a nominal temperature corresponding to a cruise operating condition of the aircraft engine.

11. The bypass valve as defined in claim 10 , wherein the flow restrictor includes a perforated body installed inside the first or second oil passages.

12. The bypass valve as defined in claim 11 , wherein the flow restrictor is disposed inside the second oil passage.

13. The bypass valve as defined in claim 10 , wherein the flow restrictor is disposed inside the first oil passage.

14. The bypass valve as defined in claim 10 , wherein the valve member is part of a self-regulating thermostatic valve.

15. The bypass valve as defined in claim 10 , wherein the flow restrictor defining a reduction of at least 50% in flow-receiving cross-sectional area relative to the first oil passage.

16. A method of cooling oil of an aircraft engine, the method comprising:
receiving the oil;
apportioning the oil into a first portion of the oil and a second portion of the oil based on an operating condition of the aircraft engine;
directing the first portion of the oil through a first heat exchanger facilitating heat transfer from the first portion of the oil to a first fluid, the first portion of the oil being directed through a flow restrictor defining a constriction to restrict the first portion of the oil through the first heat exchanger, the flow restrictor being disposed inside a first oil passage, the flow restrictor being sized to not substantially increase a pressure differential across the flow restrictor when the oil is at a nominal temperature corresponding to a cruise operating condition of the aircraft engine;
directing the second portion of the oil through a bypass oil passage while the first portion of the oil is directed through the first heat exchanger and through the flow restrictor, the bypass oil passage allowing the second portion of the oil to bypass the first heat exchanger; and
directing the second portion of the oil through a second heat exchanger facilitating heat transfer from the second portion of the oil to a second fluid.

17. The method as defined in claim 16 , wherein the first fluid is air and the second fluid is fuel.

18. The method as defined in claim 17 , comprising directing the first portion of the oil through the second heat exchanger.

19. The method as defined in claim 16 , wherein the flow restrictor is disposed upstream of the first heat exchanger relative to a flow of the first portion of the oil through the first heat exchanger.

20. The method as defined in claim 16 , wherein the flow restrictor is disposed downstream of the first heat exchanger relative to a flow of the first portion of the oil through the first heat exchanger.

Assignees

• Pratt & Whitney Canada

Inventors

• Walz Andrew
• Domingo Ritchie

Classifications

• F05D2260/98

  Lubrication · CPC title

• F01D25/20

  using lubrication pumps · CPC title

• F16N2210/12

  Gearings · CPC title

• F16N2210/08

  Aircraft · CPC title

• F16N2210/02

  Turbines · CPC title