Propellor blade angle control system

Patent metadata

Field	Value
Publication number	US-2018072402-A1
Application number	US-201715612522-A
Country	US
Kind code	A1
Filing date	Jun 2, 2017
Priority date	Sep 12, 2016
Publication date	Mar 15, 2018
Grant date	—

Abstract

A control circuit for changing the angle of propeller blades includes a propeller pitch change mechanism, and a fixed-displacement pump providing the supply of oil from an engine oil return system. A valve has an outlet port to direct oil from a cavity of the valve, and a pitch port in fluid communication with the pitch change mechanism. A spool of the valve is operable between a first position and a second position to respectively open and close the outlet port, and direct oil flow away from or to the pitch change mechanism.

First claim

1 . An oil system of a turboprop gas turbine engine having a propeller of an aircraft, the propeller having a plurality of variable pitch propeller blades, the oil system comprising:
an engine oil return system having a supply of oil; and a propeller blade angle control circuit communicating with the engine oil return system, including:
a propeller pitch change mechanism;
a fixed-displacement pump communicating between the propeller pitch change mechanism and the supply of oil; and
a valve disposed downstream of the pump, the valve having a valve body with a cavity therein, the valve body including an outlet port, an inlet port, and a pitch port, the inlet port fluidly communicating with the pump, the outlet port fluidly communicating with the engine oil return system via an oil cooling line, and the pitch port fluidly communicating with the propeller pitch change mechanism, the valve including a spool within the cavity displaceable between a first position and a second position within the valve body;
wherein in the first position, the spool permits communication through the outlet port to the oil cooling line, and in the second position the spool substantially blocks the outlet port to permit oil to flow through the pitch port to the propeller pitch change mechanism.

2 . The oil system as defined in claim 1 , wherein the spool is in the second position during transient operation of the propeller pitch change mechanism.

3 . The oil system as defined in claim 2 , wherein during transient operation of the propeller pitch change mechanism, the spool increases an opening of the pitch port while simultaneously blocking the outlet port.

4 . The oil system as defined in claim 1 , wherein the spool is in the first position during steady-state operation of the propeller pitch change mechanism.

5 . The oil system as defined in claim 4 , wherein in the first position the spool permits oil to flow through the outlet port and the pitch port.

6 . The oil system as defined in claim 1 , wherein the spool is displaceable within the cavity to modify an opening of the pitch port.

7 . The oil system as defined in claim 1 , wherein the spool is displaceable within the cavity to always leave the pitch port at least partially unblocked.

8 . The oil system as defined in claim 1 , wherein the outlet port includes a first outlet port and a second outlet port, the first outlet port remaining continuously unblocked, the spool in the first position permitting oil to flow through the second outlet port to the oil cooling line, and the spool in the second position substantially blocking the second outlet port.

9 . A method of supplying oil to a propeller pitch change mechanism, comprising:
pumping the oil at a constant flow rate to a valve positioned upstream of the propeller pitch change mechanism; and controlling access of the pumped oil to an oil cooling leakage path extending from the valve to an engine oil return system, including directing the oil from the valve along the oil cooling leakage path to the engine oil return system to cool the oil, and blocking access to the oil cooling leakage path with the valve to direct the oil toward the propeller pitch change mechanism to modify an angle of propeller blades.

10 . The method as defined in claim 9 , wherein blocking access to the oil cooling leakage path includes blocking access to the oil cooling leakage path during transient operation of the propeller pitch change mechanism.

11 . The method as defined in claim 10 , wherein blocking access includes blocking a port of the valve during transient operation to maximize a flow of oil toward the propeller pitch change mechanism.

12 . The method as defined in claim 11 , wherein blocking the port of the valve includes blocking the port of the valve while simultaneously opening another port of the valve in fluid communication with the propeller pitch change mechanism.

13 . The method as defined in claim 12 , wherein opening said another port of the valve includes always maintaining said another port at least partially open.

14 . The method as defined in claim 9 , wherein directing the oil along the oil cooling leakage path includes directing the oil along the oil cooling leakage path during steady-state operation of the propeller pitch change mechanism.

15 . The method as defined in claim 14 , wherein directing the oil along the oil cooling leakage path during steady-state operation includes opening both a first port of the valve in fluid communication with the oil cooling leakage path, and a second port of the valve in fluid communication with the propeller pitch change mechanism.

16 . The method as defined in claim 9 , wherein controlling access of the pumped oil includes controlling opening of a first port of the valve in fluid communication with the oil cooling leakage path as a function of an oil pressure demand of the propeller pitch change mechanism.

17 . A propeller blade angle control circuit, comprising:
a propeller pitch change mechanism; a fixed-displacement pump located upstream of the propeller pitch change mechanism and providing a supply of oil from an engine oil return system to the propeller pitch change mechanism; and a valve disposed between the pump and the propeller pitch change mechanism, the valve having a valve body with a cavity therein, the valve body including an outlet port, an inlet port, and a pitch port, the inlet port fluidly communicating with the pump, the outlet port fluidly communicating with the engine oil return system via an oil cooling line, and the pitch port fluidly communicating with the propeller pitch change mechanism, the valve including a spool within the cavity displaceable between a first position and a second position within the valve body; wherein in the first position, the spool permits communication through the outlet port to the oil cooling line, and in the second position the spool substantially blocks the outlet port to permit oil to flow through the pitch port to the propeller pitch change mechanism.

18 . The circuit as defined in claim 17 , wherein the spool is in the second position during transient operation of the propeller pitch change mechanism.

19 . The circuit as defined in claim 18 , wherein during transient operation of the propeller pitch change mechanism, the spool increases an opening of the pitch port while simultaneously blocking the outlet port.

20 . The circuit as defined in claim 17 , wherein the spool is in the first position during steady-state operation of the propeller pitch change mechanism.

Assignees

• Pratt & Whitney Canada

Inventors

• Waddleton David

Classifications

• F02C3/04

  having a turbine driving a compressor (power transmission arrangements F02C7/36; control of working fluid flow F02C9/16) · CPC title

• F01M5/002

  Cooling · CPC title

• B64C11/38 Primary

  fluid, e.g. hydraulic · CPC title

• B64C11/385 Primary

  comprising feathering, braking or stopping systems · CPC title

• F05D2220/323

  for aircraft propulsion, e.g. jet engines · CPC title