阅读说明：本技术 用于使飞行器推进器顺桨的系统和方法 (System and method for feathering an aircraft propeller ) 是由 J.沙哈尔 C.里希奥 D.麦克格拉斯 G.辛加鲁 于 2019-07-10 设计创作，主要内容包括：提供了一种用于使飞行器推进器顺桨的系统和方法。飞行器推进器联接到用于设定推进器的叶片桨距的致动器。通过调节至致动器的液压流体的供应来控制叶片桨距。提供至少一个顺桨螺线管,其包括第一螺线管线圈、第二螺线管线圈以及联接到致动器并且联接到第一和第二螺线管线圈的电磁阀。至少一个控制器被构造成使第一和第二螺线管线圈选择性地通电和断电。电磁阀被构造成在第一螺线管线圈和第二螺线管线圈断电时被激活,并且在被激活时被构造成调节至致动器的液压流体的供应,以用于朝向顺桨位置调节推进器的叶片桨距。(A system and method for feathering an aircraft propeller is provided. The aircraft propeller is coupled to an actuator for setting the pitch of the blades of the propeller. The blade pitch is controlled by regulating the supply of hydraulic fluid to the actuators. At least one feathering solenoid is provided that includes a first solenoid coil, a second solenoid coil, and a solenoid valve coupled to the actuator and to the first and second solenoid coils. At least one controller is configured to selectively energize and de-energize the first and second solenoid coils. The solenoid valve is configured to be activated when the first and second solenoid coils are de-energized, and configured to regulate a supply of hydraulic fluid to the actuator for adjusting the blade pitch of the propeller towards a feathered position when activated.)

1. A system for feathering an aircraft propeller having an actuator coupled thereto for setting a blade pitch of the propeller, the blade pitch being controlled by regulating a supply of hydraulic fluid to the actuator, the system comprising:

at least one feathering solenoid including a first solenoid coil, a second solenoid coil, and a solenoid valve coupled to the actuator and to the first solenoid coil and the second solenoid coil; and

at least one controller configured to selectively energize and de-energize the first and second solenoid coils,

the solenoid valve is configured to be activated when the first and second solenoid coils are de-energized, and configured to regulate the supply of hydraulic fluid to the actuator when activated for regulating the blade pitch of the propeller toward a feathered position.

2. The system of claim 1, wherein the at least one controller comprises: a first solenoid driver configured to selectively energize and de-energize the first solenoid coil; and a second solenoid driver configured to selectively energize and de-energize the second solenoid coil, the at least one controller including a first channel for controlling the first solenoid driver and a second channel for controlling the second solenoid driver.

3. The system of claim 2, wherein the first and second solenoid drivers are configured to selectively de-energize the first and second solenoid coils in response to receiving a feathering command.

4. The system of claim 2, wherein each of the first and second solenoids comprises a first electrical switch connected to a corresponding one of the first and second solenoid coils, the first electrical switch being controllable between an open position and a closed position and configured to connect the corresponding solenoid coil to ground when in the closed position and disconnect the corresponding solenoid coil from ground when in the open position.

5. The system of claim 4, wherein the first electrical switch of the first solenoid driver is configured to default to the off position when the first channel is not powered, and the first electrical switch of the second solenoid driver is configured to default to the off position when the second channel is not powered.

6. The system of claim 4 wherein the first electrical switch of the first solenoid driver is configured to default to the open position when the first channel is inactive and the first electrical switch of the second solenoid driver is configured to default to the open position when the second channel is inactive.

7. The system of claim 4, wherein each of the first and second solenoid drivers comprises a second electrical switch connected to a corresponding one of the first and second solenoid coils, the second electrical switch controllable between the open and closed positions and configured to: when in the closed position, connecting the corresponding solenoid coil to a power source, and when in the open position, disconnecting the corresponding solenoid coil from the power source.

8. The system of claim 7, wherein the corresponding solenoid coil is de-energized when at least one of the first electrical switch and the second electrical switch is in the open position.

9. The system of claim 7, wherein the second electrical switch of the first solenoid driver is configured to default to the off position when the first channel is not powered and the second electrical switch of the second solenoid driver is configured to default to the off position when the second channel is not powered.

10. The system of claim 7, wherein the first and second electrical switches of the first solenoid driver are configured to default to the off position when the first channel is not powered, and the first and second electrical switches of the second solenoid driver are configured to default to the off position when the second channel is not powered.

11. The system of any of claims 2 to 10, wherein the at least one controller is a Full Authority Digital Engine Controller (FADEC) and the first and second channels are redundant channels.

12. A method for feathering an aircraft propeller having an actuator coupled thereto for setting a blade pitch of the propeller, the blade pitch being controlled by regulating a supply of hydraulic fluid to the actuator, the method comprising:

receiving a command to feather the propeller;

in response to receiving a command, commanding at least one controller to de-energize first and second feathering solenoid coils coupled to solenoid valves coupled to the actuator; and

activating the solenoid valve when the first and second solenoid coils are de-energized, the solenoid valve, when activated, regulating a supply of hydraulic fluid to the actuator for regulating the blade pitch of the propeller toward a feathered position.

13. The method of claim 12, wherein commanding the at least one controller to de-energize the first and second solenoid coils comprises: commanding a first solenoid driver to de-energize the first solenoid coil and commanding a second solenoid driver to de-energize the second solenoid coil.

14. The method of claim 13, wherein commanding the first solenoid driver to de-energize the first solenoid coil comprises: commanding a first electrical switch of the first solenoid driver into an open position for disconnecting the first solenoid coil from ground; and wherein commanding the second solenoid driver to de-energize the second solenoid coil comprises: commanding a first electrical switch of the second solenoid driver into an open position for disconnecting the second solenoid coil from ground.

15. The method of claim 14, wherein the first electrical switch of the first solenoid driver is configured to default to the open position when a first channel of the at least one controller is not powered, and the first electrical switch of the second solenoid driver is configured to default to the open position when a second channel of the at least one controller is not powered, the first channel being used to control the first solenoid driver and the second channel being used to control the second solenoid driver.

16. The method of claim 13, wherein commanding the first solenoid driver to de-energize the first solenoid coil comprises: commanding a second electrical switch of the first solenoid driver into an open position for disconnecting the first solenoid coil from a power source; and wherein commanding the second solenoid driver to de-energize the second solenoid coil comprises: commanding a second electrical switch of the second solenoid driver into an open position for disconnecting the second electromagnetic coil from the power source.

17. The method of claim 16, wherein the second electrical switch of the first solenoid driver is configured to default to the off position when the first channel is not powered and the second electrical switch of the second solenoid driver is configured to default to the off position when the second channel is not powered.

18. The method of claim 16, wherein the first and second electrical switches of the first solenoid driver are configured to default to the off position when the first channel is not powered, and the first and second electrical switches of the second solenoid driver are configured to default to the off position when the second channel is not powered.

Technical Field

The present application relates generally to propeller control systems for aircraft engines, and more particularly to systems and methods for feathering aircraft propellers.

Background

The actuation of the propeller blade pitch to the feathered position is typically done by a bypass circuit of the pitch control unit in order to rapidly actuate the propeller blades to change the blade pitch to the feathered position. Typically, the bypass circuit is controlled by an electro-hydraulic actuator known as a feathering solenoid.

The feathering solenoid, which is a sub-component of the pitch actuator of the pitch control unit, typically has a single coil that is electrically driven to change the blade pitch to the feathered position. In particular, when the feathering solenoid is electrically driven, the oil used to control the pitch actuator is redirected to drive the propeller blades in the pitch direction towards the feathered position.

However, since existing propeller control systems use electrical power to feather the propeller, the propeller control system will not be able to feather the propeller in case of loss of electrical power.

Accordingly, there is a need for improved systems and methods for feathering aircraft propellers.

Disclosure of Invention

According to an aspect, a system for feathering an aircraft propeller is provided. The aircraft propeller has an actuator coupled thereto for setting a blade pitch of the propeller. The blade pitch is controlled by regulating the supply of hydraulic fluid to the actuators. The system comprises: at least one feathering solenoid including a first solenoid coil, a second solenoid coil, and a solenoid valve coupled to the actuator and to the first and second solenoid coils; and at least one controller configured to selectively energize and de-energize the first and second solenoid coils, wherein the solenoid valve is configured to be activated when the first and second solenoid coils are de-energized, and configured to regulate a supply of hydraulic fluid to the actuator when activated to adjust a blade pitch of the propeller toward a feathered position.

In some embodiments, the at least one controller comprises: a first solenoid driver configured to selectively energize and de-energize the first solenoid coil; and a second solenoid driver configured to selectively energize and de-energize the second solenoid coil, the at least one controller including a first channel for controlling the first solenoid driver and a second channel for controlling the second solenoid driver.

In some embodiments, the first and second solenoid drivers are configured to de-energize the first and second solenoid coils, respectively, in response to receiving a feathering command.

In some embodiments, each of the first and second solenoid drivers includes a first electrical switch connected to a corresponding one of the first and second solenoid coils, the first electrical switch controllable between an open position and a closed position and configured to: when in the closed position, the corresponding solenoid coil is connected to ground, and when in the open position, the corresponding solenoid coil is disconnected from ground.

In some embodiments, the first electrical switch of the first solenoid driver is configured to default to an off position when the first channel is not powered, and the first electrical switch of the second solenoid driver is configured to default to an off position when the second channel is not powered.

In some embodiments, the first electrical switch of the first solenoid driver is configured to default to the off position when the first channel is inactive, and the first electrical switch of the second solenoid driver is configured to default to the off position when the second channel is inactive.

In some embodiments, each of the first and second solenoid drivers includes a second electrical switch connected to a corresponding one of the first and second solenoid coils, the second electrical switch being controllable between an open position and a closed position and configured to: when in the closed position, the corresponding solenoid coil is connected to the power source, and when in the open position, the corresponding solenoid coil is disconnected from the power source.

In some embodiments, when at least one of the first electrical switch and the second electrical switch is in the open position, the corresponding solenoid coil is de-energized.

In some embodiments, the second electrical switch of the first solenoid driver is configured to default to an off position when the first channel is not powered, and the second electrical switch of the second solenoid driver is configured to default to an off position when the second channel is not powered.

In some embodiments, the first and second electrical switches of the first solenoid driver are configured to default to an off position when the first channel is not powered, and the first and second electrical switches of the second solenoid driver are configured to default to an off position when the second channel is not powered.

In some embodiments, the at least one controller is a Full Authority Digital Engine Controller (FADEC) and the first and second channels are redundant channels.

According to an aspect, a method for feathering an aircraft propeller. The aircraft propeller has an actuator connected thereto for setting the pitch of the propeller blades. The blade pitch is controlled by regulating the supply of hydraulic fluid to the actuators. The method comprises the following steps: receiving a command to feather the propeller; in response to receiving the command, commanding the at least one controller to de-energize the first and second feathering solenoid coils, the first and second solenoid coils coupled to a solenoid valve coupled to an actuator; and activating a solenoid valve when the first and second solenoid coils are de-energized, the solenoid valve, when activated, regulating a supply of hydraulic fluid to the actuator for adjusting the pitch of the blades of the propeller towards a feathered position.

In some embodiments, commanding the at least one controller to de-energize the first and second solenoid coils comprises: the first solenoid driver is commanded to de-energize the first solenoid coil and the second solenoid driver is commanded to de-energize the second solenoid coil.

In some embodiments, commanding the first solenoid driver to de-energize the first solenoid coil comprises: commanding the first electrical switch of the first solenoid driver into an open position to disconnect the first solenoid coil from ground, and commanding the second solenoid driver to de-energize the second solenoid coil comprises: the first electrical switch of the second solenoid driver is commanded into an open position to disconnect the second solenoid coil from ground.

In some embodiments, the first electrical switch of the first solenoid driver is configured to default to an off position when a first channel of the at least one controller is not energized, and the first electrical switch of the second solenoid driver is configured to default to an off position when a second channel of the at least one controller is not energized, the first channel for controlling the first solenoid driver and the second channel for controlling the second solenoid driver.

In some embodiments, commanding the first solenoid driver to de-energize the first solenoid coil comprises: commanding the second electrical switch of the first solenoid driver into an open position to disconnect the first solenoid coil from the power source, and commanding the second solenoid driver to de-energize the second solenoid coil comprises: commanding a second electrical switch of the second solenoid driver into an open position to disconnect the second solenoid coil from the power source.

In some embodiments, the second electrical switch of the first solenoid driver is configured to default to an off position when the first channel is not powered, and the second electrical switch of the second solenoid driver is configured to default to an off position when the second channel is not powered.

In some embodiments, the first and second electrical switches of the first solenoid driver are configured to default to an off position when the first channel is not powered, and the first and second electrical switches of the second solenoid driver are configured to default to an off position when the second channel is not powered.

Drawings

Referring now to the attached drawings, wherein:

FIG. 1 is a schematic cross-sectional view of a gas turbine engine;

FIG. 2 is a block diagram of an example of a pitch control unit in accordance with an illustrative embodiment;

FIG. 3 is a schematic view of a system for feathering an aircraft propeller, according to an illustrative embodiment;

FIG. 4 is a schematic view of the system of FIG. 3, showing an example in which the propellers are oriented to be feathered;

FIG. 5 is a schematic view of the system of FIG. 3, showing an example in which the propeller may be de-feathered;

FIG. 6 is a flow diagram of a method for feathering an aircraft propeller, according to an embodiment; and

fig. 7 is a block diagram of an exemplary computing system for implementing the method of fig. 6, according to an embodiment.

Detailed Description

FIG. 1 illustrates a gas turbine engine 10 of the type typically provided for subsonic flight, comprising: an inlet 12 through which ambient air is propelled; a compressor section 14 for pressurizing air; a combustor 16, wherein compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases; and a turbine section 18 for extracting energy from the combustion gases. Turbine section 18 illustratively includes: a compressor turbine 20, which drives the compressor assembly and accessories; and at least one power or free turbine 22 that drives the rotor shaft 24 in rotation about the longitudinal propeller shaft axis a, independently of the compressor turbine 20 and through a reduction gearbox 26. The hot gases may then be discharged through a discharge stub 28. The gas generator of engine 10 illustratively includes a compressor section 14, a combustor 16, and a turbine section 18. A rotor 30 in the form of a propeller through which ambient air is propelled is carried in a propeller hub 32. The rotor 30 may, for example, comprise the propeller of a fixed wing aircraft or the main (or tail) rotor of a rotary wing aircraft such as a helicopter. Rotor 30 may include a plurality of circumferentially arranged blades connected to and extending radially from a hub by any suitable means. The blades may also each be rotated about their own radial axis through a number of blade angles that may be varied to achieve modes of operation such as feathering (feather), full reverse, and forward thrust. The blade angle (also referred to herein as "blade pitch") of the propeller 30 may be controlled by a Pitch Control Unit (PCU) 45.

With additional reference to fig. 2, PCU 45, according to one embodiment, includes a hydraulic circuit driven by hydraulic fluid (e.g., oil) provided to the hydraulic circuit by one or more pumps of engine 10. The hydraulic circuit includes pitch actuator 220 and the blade pitch may be controlled by adjusting hydraulic fluid pressure (e.g., oil pressure) in pitch actuator 220, which causes rotational twisting of the blade. That is, the blade pitch of propeller 30 is variable and may be modified by pitch actuator 220. An electronic controller (not shown in fig. 2) may command PCU 45 to change the blade pitch. The electronic controller may receive commands to change the pitch of the blades from an aircraft joystick (aircraft lever) or an aircraft computer. For example, the electronic controller may receive a command to control the pitch of the blades into a feathered position. Alternatively, the PCU 45 may be commanded to change blade pitch using a mechanical or hydro-mechanical control mechanism (not shown) connected to a control rod in the cockpit of the aircraft. Pitch actuator 220 may take different forms depending on the type of engine and/or aircraft. The pitch actuator may be a hydraulic actuator or an electro-hydraulic actuator. In some embodiments, there may be a transmission, for example a transmission present on a turbo-propelled aircraft. The implementation of PCU 45 may vary depending on the actual implementation.

Fig. 3 shows a system 300 for feathering a propeller of an engine, such as engine 10 of fig. 1. The system 300 comprises an electro-hydraulic actuator 320 for feathering the blade pitch of the propeller 30. It should be appreciated that although a single electro-hydraulic actuator 320 is shown in FIG. 3 and described herein, the control system 300 may include more than one electro-hydraulic actuator. The electro-hydraulic actuator 320 is referred to herein as a "feathering solenoid" or "solenoid". In the illustrated embodiment, the feathering solenoid is a dual coil feathering solenoid. Alternatively, two single coil feathering solenoids may be used. Feathering solenoid 320 is configured to modify the blade pitch of propeller 30 to drive propeller 30 toward a feathered position. According to an embodiment, feathering solenoid 320 is provided as part of PCU 45. According to an embodiment, the feathering solenoid 320 is provided separately from the pitch actuator 220. The pitch actuator 220 is a device that allows fine tuning of the propeller blade angle over the entire range of propeller blade pitches. Although pitch actuator 220 may be used to drive the propeller into feathering, it will typically take more time than it would take to utilize feathering solenoid 320. In one embodiment, the use of a feathering solenoid 320 that performs a feathering function ensures that: propeller control via pitch actuator 220 and propeller protection function via feathering solenoid 320 are separate controls and outputs. It will be appreciated that in some embodiments, this ensures that no single electrical fault will result in the propeller 30 not being able to feather. Although feathering solenoid 320 is used to feather propeller 30 and is shown as a separate actuator from pitch actuator 220, it should be understood that a common actuator for propeller feathering and pitch variation may be used.

Reference to "feathering" or adjusting the blade pitch of the propeller 30 to "feather" the propeller refers to orienting the blades of the propeller 30 to a feathered position. Reference to "de-feathering" or "de-feathering" of the propeller 30 refers to orienting the blades of the propeller 30 to a position other than the feathered position. In the feathered position, the blade pitch is positioned in a position where there is maximum rotational resistance and minimum forward movement. For example, control of propeller blade pitch into the feathered position may be performed on the ground after engine start-up, on the ground or before shutdown of the engine in flight, and/or on an engine that fails during the takeoff phase.

As shown, the feathering solenoid 320 includes a first solenoid coil 321, a second solenoid coil 322, and a solenoid valve 323. The first solenoid driver 331 is configured to energize (or power) the first solenoid coil 321 by supplying current to the first solenoid coil 321 from a first power source (not shown in fig. 3), and to de-energize (or de-energize) the first solenoid coil 321 by not supplying current to the first solenoid coil 321. Similarly, second solenoid driver 332 is configured to energize second solenoid coil 322 by supplying current to second solenoid coil 322 from a second power source (not shown in fig. 3), and to de-energize second solenoid coil 322 by not supplying current to second solenoid coil 322. Feathering solenoid 320 is configured to actuate the propeller blades to change the blade pitch to a feathered position when both first and second solenoid coils 321, 322 are de-energized. For example, feathering solenoid 320 is configured to control a bypass circuit of pitch control unit 45 to drive propeller 30 into a feathered position. According to an embodiment, when the first and second solenoid coils 321, 322 are de-energized, hydraulic fluid from the small pitch hydraulic circuit is redirected to drain, and when this occurs, the relief valve (protection valve) of the pitch actuator 220 moves such that the flow of hydraulic fluid to the large pitch hydraulic circuit increases. This therefore typically increases the rate at which the propeller blades change their blade pitch to a feathered position. In other words, solenoid valve 323 is configured to control the hydraulic fluid in pitch actuator 220 in order to pitch the blades of propeller 30 to feather. The solenoid valve 323 is configured to be activated when both the first and second solenoid coils 321, 322 are de-energized. When the solenoid valve 323 is activated, the solenoid valve 323 causes the supply of hydraulic fluid to the propeller 30 to be modified for adjusting the blade pitch of the propeller 30 towards the feathered position. In particular, when the solenoid valve 323 is activated, the solenoid valve 323 is configured to control the supply of hydraulic fluid in the pitch actuator 220 to drive the propeller into feathering. Controlling the supply of hydraulic fluid in pitch actuator 220 to drive the propeller to feather may include: redirecting hydraulic fluid in pitch actuator 220, adjusting a pressure of the hydraulic fluid, and/or any other suitable adjustment to the hydraulic fluid in pitch actuator 220.

In one embodiment, by requiring both solenoid coils 321, 322 to be de-energized to feather the propeller 30, it should be understood that if one of the power sources fails (i.e., is inoperative) or if one of the solenoid drivers 331, 332 fails, the active one of the power sources or solenoid drivers may still be used to command the propeller 30 to feather or de-feather.

Referring to fig. 4 and 5, according to an embodiment, the first solenoid driver 331 is configured to energize the first solenoid coil 321 by connecting (e.g., as shown in fig. 5) the first solenoid coil 321 to the first power source 401 and to de-energize the first solenoid coil 321 by disconnecting (e.g., as shown in fig. 4) the first solenoid coil 321 from the first power source 401. Similarly, according to an embodiment, second solenoid driver 332 is configured to energize second solenoid coil 322 by connecting (e.g., as shown in fig. 5) second solenoid coil 322 to second power source 402 and to de-energize second solenoid coil 322 by disconnecting (e.g., as shown in fig. 4) second solenoid coil 322 from second power source 402. The first power source 401 and the second power source 402 are independent power sources. When the first solenoid driver 331 is inoperative (e.g., has lost power from the first power source 401 or has failed), the first solenoid coil 321 is de-energized. Similarly, when the second solenoid driver 332 is inactive (e.g., has lost power from the second power source 402 or has failed), the second solenoid coil 322 is de-energized.

As shown, the first solenoid coil 321 has two ends, one of which is for connection to the first voltage V1 of the first power source 401 and the other of which is for connection to ground GND. Similarly, the second solenoid coil 322 has two ends, one end for connecting to the second voltage V2 of the second power source 402 and the other end for connecting to the ground GND.

According to an embodiment, each of the solenoid drivers 331, 332 includes a first electrical switch 411, 412 controllable between an open position (e.g., as shown in fig. 4) and a closed position (e.g., as shown in fig. 5). When in the closed position, each of the first electrical switches 411, 412 is configured to connect a corresponding one of the solenoid coils 321, 322 to ground GND in order to energize the corresponding solenoid coil 321, 322. When in the open position, each of the first electrical switches 411, 412 is configured to disconnect the corresponding solenoid coil 321, 322 from ground GND in order to de-energize the corresponding solenoid coil 321, 322. In the exemplary embodiment, first solenoid coil 321 is connected to a first voltage V1, and first electrical switch 411 of first solenoid driver 331 is used to connect or disconnect first solenoid coil 321 to or from first power source 401. Similarly, in the exemplary embodiment, second solenoid coil 322 is connected to second voltage V2, and first electrical switch 412 of second solenoid driver 332 is used to connect or disconnect second solenoid coil 322 from second power source 402.

The first switches 411, 412 may be controlled by the electronic controller 400, and in the illustrated embodiment, the electronic controller 400 includes the switches 411, 412. Alternatively, the switches 411, 412 may be separate from the electronic controller 400. Each of the first switches 411, 412 may be referred to as Low Side Switches (LSSs) because they are used to connect or disconnect the solenoid coils 321, 322 to or from ground GND. According to an embodiment, the first switches 411, 412 are configured to default to an off position when the electronic controller 400 is not powered, thereby driving the propeller 30 to feather.

In some embodiments, each of the solenoid drivers 331, 332 includes a second electrical switch 413, 414 controllable between an open position and a closed position. When in the closed position, each of the second electrical switches 413, 414 is configured to connect the corresponding solenoid coil 321, 322 to the corresponding voltage V1, V2 provided by the corresponding power source 401, 402. When in the open position, each of the second electrical switches is configured to disconnect the corresponding solenoid coil from the corresponding voltage V1, V2. The second switches 413, 414 may be controlled by the electronic controller 400, and in the illustrated embodiment, the electronic controller 400 includes the second switches 413, 414. Alternatively, the second switches 413, 414 may be separate from the electronic controller 400. Each of the second switches 413, 414 may be referred to as High Side Switches (HSS) because they are used to connect the solenoid coils 321, 322 to the voltage V1, V2 of the power source 401, 402 or to disconnect from the voltage V1, V2 of the power source 401, 402. In some embodiments, the second switches 413, 414 may be omitted or may be configured to remain closed at all times. In some embodiments, the second switches 413, 414 are configured to default to a closed position (even when the electronic controller 400 is not powered). Alternatively, the second switches 413, 414 may be configured to default to an open position, and the first switches 411, 412 may be configured to default to a closed position. Thus, in some embodiments, second switches 413, 414 are configured to default to an off position when electronic controller 400 is not powered, thereby driving propeller 30 to feather. In other embodiments, the first switch (e.g., first switch 411) and the second switch (e.g., second switch 413) of a given solenoid driver (e.g., first solenoid driver 331) are both controlled by the controller 400 such that the pair of switches (e.g., first switch 411 and second switch 413) are in an open or closed position. Accordingly, switches 411, 412, 413, 414 may all be configured to default to an off position when electronic controller 400 is not powered, thereby driving propeller 30 to feather.

According to an embodiment, the electronic controller 400 includes a first channel a for controlling the first solenoid driver 331 and a second channel B for controlling the second solenoid driver 332. The first channel a is powered by a first power supply 401 and the second channel B is powered by a second power supply 402. According to an embodiment, the controller 400 is connected to two independent power supplies to provide the power supplies 401, 402. Thus, although the power supplies 401, 402 are shown as part of the controller 400, the power supplies 401, 402 may be external to the controller 400. In some embodiments, electronic controller 400 is a Full Authority Digital Engine Controller (FADEC). The electronic controller 400 may be referred to as a dual-channel electronic controller or dual-channel FADEC. According to an embodiment, channel A, B is a separate redundant channel that provides dual functionality. Alternatively, the first and second solenoid drivers 331 and 332 may be provided as separate electronic controllers (implemented similarly to the electronic controller 400).

Each channel a or B may control its respective switch 411, 412. This may be referred to as a slave ACTIVE/ACTIVE system. The control of its respective switch 411, 412 by channel a or B may be independent of the in-channel control (CIC) of the electronic controller 400. In the case of single channel scheduling, such as when one of the channels (e.g., channel B) is inoperative (e.g., malfunctioning or unpowered), only one of the feathering solenoids 320 (e.g., first solenoid coil 321) would need to be commanded to de-energize to feather the propeller 30. This is because the first switch (e.g., the first switch 412 of the first solenoid driver 332) of the inactive channel (e.g., channel B) is configured to default to the off position when the channel is inactive. Since both solenoid coils 321, 322 of feathering solenoid 320 need to be de-energized to feather propeller 30, propeller 30 is able to de-feather if the low side switch (e.g., first switch 411) of the active channel (e.g., channel a) is in the closed position.

In some embodiments, the first electrical switch 411 of the first solenoid driver 331 is configured to default to an off position when the first channel a is not powered, and the first electrical switch 412 of the second solenoid driver 332 is configured to default to an off position when the second channel B is not powered. Similarly, in some embodiments, the second electrical switch 413 of the first solenoid driver 331 is configured to default to an off position when the first channel a is not powered, and the second electrical switch 414 of the second solenoid driver 332 is configured to default to an off position when the second channel B is not powered. In some embodiments, the first electrical switch 411 and the second electrical switch 413 of the first solenoid driver 331 are configured to default to an off position when the first channel a is not powered, and the first electrical switch 412 and the second electrical switch 414 of the second solenoid driver 332 are configured to default to an off position when the second channel B is not powered.

It will be appreciated that in the event of a loss of power, pitch actuator 220 in PCU 45 may be configured to drive propeller 30 towards a large pitch (coarse pitch) and eventually to a fully feathered state. In this case, however, both the first and second switches 411, 412 will be in the open position and the propeller 30 will be driven feathering. Furthermore, the provided configuration of the control system 300 may result in a more desirable transition to the feathered position in the event of a fire.

Referring to FIG. 6, a flow chart illustrating an exemplary method 600 for feathering an aircraft propeller is shown. Although method 600 is described herein with reference to engine 10, this is for exemplary purposes. Method 600 may be applied to any suitable engine. At step 602, a feathering command is received to drive the propeller to a feathered position to feather the propeller 30. A feathering command may be received at the controller 400 from the aircraft computer. For example, the controller 400 may receive a feathering command from a condition lever input (condition lever input) in the cockpit base or an emergency feathering command from a flight crew (e.g., via a fire handle). As another example, the feathering command may come from an auto-feathering function commanded by the aircraft or the powerplant system without initiation by flight personnel (e.g., from an auto-thruster drag limiting system). At step 604, in response to receiving the feathering command, the controller 400 is commanded to de-energize the first and second feathering solenoid coils 321, 322. In some embodiments, commanding the controller 400 to de-energize the first and second solenoid coils 321, 322 includes: first solenoid driver 331 is commanded to de-energize first solenoid coil 321 and second solenoid driver 332 is commanded to de-energize second solenoid coil 322. In some embodiments, commanding the first solenoid driver 331 to de-energize the first solenoid coil 321 comprises: commanding channel a to control the first solenoid driver 331 and commanding the second solenoid driver 332 to de-energize the second solenoid coil 322 comprises: commanding a second channel B to control the second solenoid driver 332. The command to de-energize first solenoid coil 321 and second solenoid coil 322 may be performed as described elsewhere in this document. For example, commanding the first solenoid driver 331 to de-energize the first solenoid coil 321 may include: commanding the first electrical switch 411 of the first solenoid driver 331 into an open position for removing the first current supply to the first solenoid coil 321; and commanding the second solenoid driver 332 to de-energize the second solenoid coil 322 may include: the first electrical switch 412 of the second solenoid driver 332 is commanded into an open position for removing the second current supply to the second solenoid coil 322. Further, commanding the first electrical switch 411 of the first solenoid driver 331 into the open position may include: disconnecting the first solenoid coil 321 from ground and commanding the first electrical switch 412 of the second solenoid driver 332 into the open position may include: disconnecting second solenoid coil 322 from ground. At step 606, the solenoid valve 323 is activated when the first and second solenoid coils 321, 322 are de-energized. The solenoid valve 323, when activated, regulates the supply of hydraulic fluid to the actuator 220 for adjusting the blade pitch of the propeller 30 towards the feathered position.

Referring to fig. 7, the method 600 may be at least partially implemented using a computing device 400 (also referred to herein as an electronic controller), the computing device 400 including a processing unit 712 and a memory 714, the memory 714 having stored therein computer-executable instructions 716. The processing unit 712 may include any suitable device configured to implement the system such that the instructions 716, when executed by the computing device 400 or other programmable apparatus, may cause the functions/acts/steps of the method 600 as described herein to be performed. Processing unit 712 may include, for example, any type of general purpose microprocessor or microcontroller, a Digital Signal Processing (DSP) processor, a Central Processing Unit (CPU), an integrated circuit, a Field Programmable Gate Array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuitry, or any combination thereof.

Memory 714 may include any suitable known or other machine-readable storage medium. Memory 714 may include a non-transitory computer-readable storage medium, such as, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory 714 may comprise any type of suitable combination of computer memory, internal or external to the device, such as Random Access Memory (RAM), Read Only Memory (ROM), Compact Disc Read Only Memory (CDROM), electro-optic memory, magneto-optic memory, Erasable Programmable Read Only Memory (EPROM) and Electrically Erasable Programmable Read Only Memory (EEPROM), ferroelectric RAM (fram), and the like. Memory 714 may include any storage device (e.g., an apparatus) suitable for retrievably storing machine-readable instructions 716 that are executable by processing unit 712. In some embodiments, computing device 400 may be implemented as part of a Full Authority Digital Engine Controller (FADEC) or other similar device, including an Electronic Engine Controller (EEC), an Engine Control Unit (ECU), or the like.

The methods and systems for feathering aircraft propellers described herein may be implemented in a high level procedural or object oriented programming or scripting language, or a combination thereof, to communicate with or facilitate the operation of a computer system (e.g., computing device 400). Alternatively, the method and system for feathering aircraft propellers may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the method and system for feathering an aircraft propeller may be stored on a storage medium or device, such as a ROM, magnetic disk, optical disk, flash drive, or any other suitable storage medium or device. The program code can be read by a general-purpose or special-purpose programmable computer, for constructing and operating the computer when the computer reads a storage medium or device to perform the procedures described herein. Embodiments of the method and system for feathering aircraft propellers may also be considered to be implemented by a non-transitory computer readable storage medium having a computer program stored thereon. The computer program may comprise computer readable instructions which cause a computer, or in some embodiments the processing unit 712 of the computing device 400, to operate in a specific and predefined manner to perform the functions described herein.

Computer-executable instructions may take many forms, including program modules, executable by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Generally, the functionality of the program modules may be combined or distributed as desired in various embodiments.

The above description is intended to be exemplary only, and those skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Still other modifications that fall within the scope of the invention will be readily apparent to those skilled in the art upon review of this disclosure.

Various aspects of the methods and systems for feathering aircraft propellers may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and are therefore not limited in their application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. While particular embodiments have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. The scope of the appended claims should not be limited to the embodiments set forth in the examples, but should be accorded the broadest reasonable interpretation consistent with the description as a whole.