FLUID SYSTEM WITH MULTI-MODE TRANSFER VALVE

A fluid system is provided that includes a first actuator, a second actuator and a valve system. The valve system includes a first control valve, a second control valve and a transfer valve. During a first mode of operation, the transfer valve is configured to fluidly couple the first control valve to the first actuator and fluidly couple the second control valve to the second actuator, and the transfer valve is also configured to fluidly decouple the first control valve from the second actuator and fluidly decouple the second control valve from the first actuator. During a second mode of operation, the transfer valve is configured to fluidly couple the first control valve to the first actuator and the second actuator, and the transfer valve is also configured to fluidly decouple the second control valve from the first actuator and the second actuator.

BACKGROUND OF THE DISCLOSURE

1. Technical Field

This disclosure relates generally to a fluid system and, more particularly, to backup modes of operation for the fluid system.

2. Background Information

A fluid system for an aircraft may include multiple fluid actuators, where each fluid actuator is controlled by a respective electrohydraulic servo valve (EHSV). Each fluid actuator may also be selectively controllable by a respective backup electrohydraulic servo valve. Each fluid actuator may thereby be associated with two different electrohydraulic servo valves. While such a fluid system has various benefits, there is still room in the art for improvement.

SUMMARY OF THE DISCLOSURE

According to an aspect of the present disclosure, a fluid system is provided that includes a first actuator, a second actuator and a valve system. The valve system includes a first control valve, a second control valve and a transfer valve. During a first mode of operation, the transfer valve is configured to fluidly couple the first control valve to the first actuator and fluidly couple the second control valve to the second actuator, and the transfer valve is also configured to fluidly decouple the first control valve from the second actuator and fluidly decouple the second control valve from the first actuator. During a second mode of operation, the transfer valve is configured to fluidly couple the first control valve to the first actuator and the second actuator, and the transfer valve is also configured to fluidly decouple the second control valve from the first actuator and the second actuator.

According to another aspect of the present disclosure, another fluid system is provided that includes a first actuator and a valve system. The valve system includes a first control valve, a second control valve and a transfer valve. The transfer valve includes a first station first passage and a second station first passage. A minimum flow area of the first station first passage is less than a minimum flow area of the second station first passage. During a first mode of operation, the transfer valve is configured to fluidly couple the first control valve to the first actuator through the first station first passage. During a second mode of operation, the transfer valve is configured to fluidly couple the second control valve to the first actuator through the second station first passage. The second control valve is fluidly decoupled from the first actuator during the first mode of operation. The first control valve is fluidly decoupled from the first actuator during the second mode of operation.

According to still another aspect of the present disclosure, an operating method is provided. During a first mode, a first control valve is fluidly coupled to a first actuator through a transfer valve, and a second control valve is fluidly coupled to a second actuator through the transfer valve. During a second mode, the first control valve is fluidly coupled to the first actuator and the second actuator through the transfer valve, and the second control valve is fluidly decoupled from the second actuator.

The operating method may also include: selecting the first mode when the first control valve and the second control valve are each fully operational; and selecting the second mode when a fault is detected associated with the second control valve.

Flow through the transfer valve from the first control valve to the first actuator may be restricted during the first mode. The flow through the transfer valve from the first control valve to the first actuator may be unrestricted during the second mode.

The first control valve and the second control valve may each be configured as an electrohydraulic servo valve.

The operating method may include moving a component of an aircraft using the first actuator and the second actuator during the first mode and/or the second mode.

The fluid system may also include a second actuator. The transfer valve may also include a first station second passage and a second station second passage, wherein a minimum flow area of the first station second passage may be less than a minimum flow area of the second station second passage. During the first mode of operation, the transfer valve may be configured to fluidly couple the second control valve to the second actuator through the first station second passage. During the second mode of operation, the transfer valve may be configured to fluidly couple the second control valve to the second actuator through the second station second passage. The first control valve may be fluidly decoupled from the second actuator during the first mode of operation and the second mode of operation.

During a third mode of operation, the transfer valve may be configured to: fluidly couple the first control valve to the first actuator and the second actuator; and fluidly decouple the second control valve from the first actuator and the second actuator.

During a third mode of operation, the transfer valve may be configured to fluidly couple the second control valve to the first actuator and the second actuator, and the transfer valve may also be configured to fluidly decouple the first control valve from the first actuator and the second actuator.

The first actuator may be configured as or otherwise include a first piston actuator. The second actuator may also or alternatively be configured as or otherwise include a second piston actuator.

The first control valve may be configured as or otherwise include a first electrohydraulic servo valve. The second control valve may also or alternatively be configured as or otherwise include a second electrohydraulic servo valve.

A first station first passage in the transfer valve may have a minimum flow area, and the first station first passage may fluidly couple the first control valve to the first actuator during the first mode of operation. A second station first passage in the transfer valve may have a minimum flow area that is greater than the minimum flow area of the first station first passage, and the second station first passage may fluidly couple the first control valve to the first actuator during the second mode of operation.

The minimum flow area of the second station first passage may be equal to or greater than 1.25 times the minimum flow area of the first station first passage.

A first station second passage in the transfer valve may have a minimum flow area, and the first station second passage may fluidly couple the second control valve to the second actuator during the first mode of operation. A second station second passage in the transfer valve may have a minimum flow area that is greater than the minimum flow area of the first station second passage, and the second station second passage may fluidly couple the first control valve to the second actuator during the second mode of operation.

The minimum flow area of the first station second passage may be equal to the minimum flow area of the first station first passage. In addition or alternatively, the minimum flow area of the second station second passage may be equal to the minimum flow area of the second station first passage.

The first actuator may include a first inlet/outlet orifice and a second inlet/outlet orifice. The transfer valve may be configured to discretely fluidly couple the first inlet/outlet orifice and the second inlet/outlet orifice to the first control valve during the first mode of operation and the second mode of operation.

The second actuator may include a first inlet/outlet orifice and a second inlet/outlet orifice. The transfer valve may be configured to discretely fluidly couple the first inlet/outlet orifice and the second inlet/outlet orifice to the second control valve during the first mode of operation. The transfer valve may be configured to discretely fluidly couple the first inlet/outlet orifice and the second inlet/outlet orifice to the first control valve during the second mode of operation.

The fluid system may also include a fluid source. The valve system may fluidly couple the fluid source to the first actuator and the second actuator.

The fluid system may also include an aircraft component. The first actuator and the second actuator may be operatively coupled to and configured to move the aircraft component.

DETAILED DESCRIPTION

FIG.1illustrates a fluid system10for an aircraft. The aircraft may be an airplane, a helicopter, a drone (e.g., an unmanned aerial vehicle (UAV)) or any other manned or unmanned aerial vehicle or system. The fluid system10of the present disclosure, however, is not limited to aircraft applications. The fluid system10, for example, may alternatively be configured for a land vehicle, an aquatic vehicle or any other mobile device or system. Moreover, the fluid system10may alternatively be configured for a stationary device or system. The fluid system10ofFIG.1includes a moveable component12, a fluid source14, one or more fluid actuators16A and16B (generally referred to as “16”) and a valve system18.

The moveable component12ofFIG.1is a moveable component of the aircraft. This moveable component12may be a component of an airframe of the aircraft. The moveable component12, for example, may be configured as an aircraft control surface; e.g., a flap, a rudder, an elevator, a tab, a spoiler, an aileron, etc. Alternatively, the moveable component12may be a component of a propulsion system for the aircraft. The moveable component12, for example, may be configured as a translating sleeve for a thrust reverser, a variable nozzle structure, etc.

The fluid source14ofFIG.1includes a fluid reservoir19and a fluid flow regulator20. The reservoir19is configured to store a quantity of fluid (e.g., hydraulic fluid, oil, etc.) before, during and/or after fluid system operation. The reservoir19, for example, may be configured as or otherwise include a tank, a cylinder, a pressure vessel, a bladder or any other type of fluid (e.g., liquid) storage container. The flow regulator20is configured to direct a flow of the fluid from the reservoir19to the fluid actuators16through the valve system18. The flow regulator20, for example, may be configured as or otherwise include a pump.

Each fluid actuator16ofFIG.1is operatively coupled to and configured to pivot, translate, shift and/or otherwise move the moveable component12. Each fluid actuator16, for example, may be configured as a linear actuator such as a hydraulic piston. Each fluid actuator16A,16B ofFIG.1, in particular, includes a cylinder21A,21B (generally referred to as “21”), a piston22A,22B (generally referred to as “22”) and an arm23A,23B (generally referred to as “23”). The piston22is arranged within an internal cavity of the cylinder21. The arm23is attached to the piston22and projects out from the cylinder21. A distal end of the arm23is directly or indirectly operatively coupled to the moveable component12. The cylinder21is coupled to a base structure; e.g., a stationary structure. With this arrangement, by increasing and/or decreasing fluid volume and/or pressure to one or both sides of the piston22within the internal cavity, each fluid actuator16may move the moveable component12by extending its actuator arm23out from the cylinder21or retracting its actuator arm23into the cylinder21. The present disclosure, however, is not limited to such an exemplary type of fluid actuators. One or more of the fluid actuators16, for example, may alternatively be configured as a fluid motor. Moreover, while the fluid actuators16ofFIG.1are associated with a common (the same) moveable component12, it is contemplated the fluid actuators16may alternatively be operatively coupled to and configured to move discrete (e.g., similarly situated) moveable components.

Referring again toFIG.1, the valve system18is configured to control a flow of the fluid from the fluid source14to and/or from each of the fluid actuators16. The valve system18ofFIG.1, for example, includes one or more control valves24A and24B (generally referred to as “24”), a transfer valve26(e.g., a switching valve) and a controller28.

Each control valve24may be configured as an electrohydraulic servo valve (EHSV). Each control valve24A,24B ofFIG.1includes one or more input and/or output (I/O) ports30A,30B (generally referred to as “30”),32A,32B (generally referred to as “32”). Each control valve24is configured to control (e.g., selectively meter) fluid flow therethrough between each of its I/O ports30and32and a respective feed from or return to the fluid source14. For example, where the valve system18is operated to extend the actuator arms23, each control valve24directs fluid received from the fluid source14to its first I/O port30, and each control valve24directs fluid received at its second I/O port32back to the fluid source14. Here, the first I/O port30is configured as a feed port to the transfer valve26, and the second I/O port32is configured as a return port from the transfer valve26. In another example, where the valve system18is operated to retract the actuator arms23, each control valve24directs fluid received from the fluid source14to its second I/O port32, and each control valve24directs fluid received at its first I/O port30back to the fluid source14. Here, the second I/O port32is configured as a feed port to the transfer valve26, and the first I/O port30is configured as a return port from the transfer valve26.

The transfer valve26includes a valve housing34and a valve body36. The transfer valve26ofFIG.1also includes a valve actuator38operatively coupled to the valve body36.

The valve housing34includes one or more first control valve ports40and42(“first valve ports”), one or more second control valve ports44and46(“second valve ports”), one or more first fluid actuator ports48and50(“first actuator ports”) and one or more second fluid actuator ports52and54(“second actuator ports”). The first valve ports40and42are respectively fluidly coupled to the I/O ports30A and32A of the first control valve24A. The second valve ports44and46are respectively fluidly coupled to the I/O ports30B and32B of the second control valve24B. The first actuator ports48and50are respectively fluidly coupled to input and/or output (I/O) ports56A and58A of the first fluid actuator16A. The second actuator ports52and54are respectively fluidly coupled to input and/or output (I/O) ports56B and58B of the second fluid actuator16B.

The valve body36ofFIG.1extends longitudinally along a centerline between a first end60of the valve body36and a second end62of the valve body36. This centerline may be a longitudinal centerline of the valve housing34and/or the valve body36. The valve body36includes a plurality of valve stations64-66arranged longitudinally along the centerline. The intermediate station64is disposed longitudinally between the first end valve station65and the second end valve station66. The first end valve station65is disposed at (e.g., on, adjacent or proximate) the body first end60. The second end valve station66is disposed at the body second end62. These valve stations64-66are configured as discrete, interconnected longitudinally extending segments of the valve body36.

The intermediate station64includes one or more first fluid actuator passages68and70(“first actuator passages”) and one or more second fluid actuator passages72and74(“second actuator passages”). Each first actuator passage68,70extends longitudinally along a centerline of that first actuator passage68,70from a valve side orifice of the respective first actuator passage68,70to an actuator side orifice of the respective first actuator passage68,70. Each second actuator passage72,74extends longitudinally along a centerline of that second actuator passage72,74from a valve side orifice of the respective second actuator passage72,74to an actuator side orifice of the respective second actuator passage72,74. With this arrangement, the intermediate station passages68,70,72and74ofFIG.1are fluidly discrete from one another within the valve body36.

Each of the intermediate station passages68,70,72and74has a minimum flow area, which is measured perpendicular to the respective centerline of that intermediate station passage68,70,72,74. This minimum flow area may extend along an entire length of the respective intermediate station passage68,70,72,74. Alternatively, the minimum flow area may be formed by a pinch point (e.g., a metering orifice) along the respective intermediate station passage68,70,72,74. The minimum flow areas of the first actuator passages68and70may be equal. The minimum flow areas of the second actuator passages72and74may be equal. The minimum flow area of one or both of the first actuator passages68and70may be equal to the minimum flow area of one or both of the second actuator passages72and74. The present disclosure, however, is not limited to such an exemplary dimensional relationship between the intermediate station passages68,70,72and74.

The first end valve station65includes one or more first fluid actuator passages76and78(“first actuator passages”) and one or more second fluid actuator passages80and82(“second actuator passages”). Each first actuator passage76and78extends longitudinally along a centerline of that first actuator passage76,78from a valve side orifice for the respective first actuator passage76,78to an actuator side orifice of the respective first actuator passage76,78. Each second actuator passage80,82extends longitudinally along a centerline of that second actuator passage80,82from the valve side orifice for the respective second actuator passage80,82to an actuator side orifice of the respective second actuator passage80,82. Thus, the first actuator passage76and the second actuator passage80each extend to (or may be otherwise fluidly coupled with) the same respective valve side orifice. Similarly, the first actuator passage78and the second actuator passage82each extend to (or may be otherwise fluidly coupled with) the same respective valve side orifice. With this arrangement, the first end station passages76and80ofFIG.1are fluidly interconnected within the valve body36, and the first end station passages78and82ofFIG.1are fluidly interconnected within the valve body36.

Each of the first end station passages76,78,80and82has a minimum flow area, which is measured perpendicular to the respective centerline of that first end station passage76,78,80,82. This minimum flow area may extend along an entire length of the respective first end station passage76,78,80,82. Alternatively, the minimum flow area may be formed by a pinch point (e.g., a metering orifice) along the respective first end station passage76,78,80,82. The minimum flow areas of the first actuator passages76and78may be equal. The minimum flow areas of the second actuator passages80and82may be equal. The minimum flow area of one or both of the first actuator passages76and78may be equal to the minimum flow area of one or both of the second actuator passages80and82. However, the minimum flow area of each first end station passage76,78,80and82may be greater than the minimum flow area of each intermediate station passage68,70,72and74. For example, the minimum flow area of each first end station passage76,78,80,82may be between 1.25 times (1.25×) or 2.5 times (2.5×) (e.g., about 1.5 times (1.5×)) greater than the minimum flow area of the respective intermediate station passage68,70,72,74. With this arrangement, flow through the intermediate station passages68,70,72and74is restricted compared to flow through the first end station passages76,78,80and82. The present disclosure, however, is not limited to such an exemplary dimensional relationship between the first end station passages76,78,80and82, nor between the first end station passages76,78,80and82and the intermediate station passages68,70,72and74. For example, the minimum flow area of each first end station passage76,78,80,82and the minimum flow area of the respective intermediate station passage68,70,72,74may be selected with any values which provide the system performance described below in further detail.

The second end valve station66includes one or more first fluid actuator passages84and86(“first actuator passages”) and one or more second fluid actuator passages88and90(“second actuator passages”). Each first actuator passage84,86extends longitudinally along a centerline of that first actuator passage84,86from a valve side orifice for the respective first actuator passage84,86to an actuator side orifice of the respective first actuator passage84,86. Each second actuator passage88,90extends longitudinally along a centerline of that second actuator passage88,90from the valve side orifice for the respective second actuator passage88,90to an actuator side orifice of the respective second actuator passage88,90. Thus, the first actuator passage84and the second actuator passage88each extend to (or may be otherwise fluidly coupled with) the respective valve side orifice. Similarly, the first actuator passage86and the second actuator passage90each extend to (or may be otherwise fluidly coupled with) the respective valve side orifice. With this arrangement, the second end station passages84and88ofFIG.1are fluidly interconnected within the valve body36, and the second end station passages86and90ofFIG.1are fluidly interconnected within the valve body36.

Each of the second end station passages84,86,88and90has a minimum flow area, which is measured perpendicular to the respective centerline of that second end station passage84,86,88,90. This minimum flow area may extend along an entire length of the respective second end station passage84,86,88,90. Alternatively, the minimum flow area may be formed by a pinch point (e.g., a metering orifice) along the respective second end station passage84,86,88,90. The minimum flow areas of the first actuator passages84and86may be equal. The minimum flow areas of the second actuator passages88and90may be equal. The minimum flow area of one or both of the first actuator passages84and86may be equal to the minimum flow area of one or both of the second actuator passages88and90. The minimum flow areas of the second end station passages84,86,88and90may also be equal to the minimum flow areas of the first end station passages76,78,80and82. However, the minimum flow area of each second end station passage84,86,88,90may be greater than the minimum flow area of each intermediate station passage68,70,72,74. For example, the minimum flow area of each second end station passage84,86,88,90may be between 1.25 times (1.25×) or 2.5 times (2.5×) (e.g., about 1.5 times (1.5×)) greater than the minimum flow area of the respective intermediate station passage68,70,72,74. With this arrangement, flow through the intermediate station passages68,70,72and74is restricted compared to flow through the second end station passages84,86,88and90. The present disclosure, however, is not limited to such an exemplary dimensional relationship between the second end station passages84,86,88and90, between the second end station passages84,86,88and90and the first end station passages76,78,80and82, nor between the second end station passages84,86,88and90and the intermediate station passages68,70,72and74. For example, the minimum flow area of each second end station passage84,86,88,90and the minimum flow area of the respective intermediate station passage68,70,72,74may be selected with any values which provide the system performance described below in further detail.

The valve body36ofFIG.1is disposed within an internal cavity of the valve housing34. The valve body36is configured for move (e.g., translate) within the valve housing34and its internal cavity between a plurality of positions. These positions include an intermediate position (seeFIG.1), a first end position (seeFIG.2) and a second end position (seeFIG.3).

When the valve body36is in the intermediate position ofFIG.1, the transfer valve26fluidly couples the first control valve24A to the first fluid actuator16A, and the transfer valve26fluidly couples the second control valve24B to the second fluid actuator16B. Here, the first control valve24A is fluidly decoupled from the second fluid actuator16B, and the second control valve24B is fluidly decoupled from the first fluid actuator16A. More particularly, each first actuator passage68,70in the intermediate station64is disposed between, aligned with and fluidly coupled to a respective one of the first valve ports40and42and a respective one of the first actuator ports48and50. The first control valve24A may thereby control (e.g., regulate) fluid flow to and/or from and is dedicated to operation of the first fluid actuator16A. Each second actuator passage72,74in the intermediate station64is disposed between, aligned with and fluidly coupled to a respective one of the second valve ports44and46and a respective one of the second actuator ports52and54. The second control valve24B may thereby control (e.g., regulate) fluid flow to and/or from and is dedicated to operation of the second fluid actuator16B.

When the valve body36is in the first end position ofFIG.2, the transfer valve26fluidly couples the first control valve24A to both the first fluid actuator16A and the second fluid actuator16B. Here, the second control valve24B is fluidly decoupled from both the first fluid actuator16A and the second fluid actuator16B. More particularly, each first actuator passage76,78in the first end station65is disposed between, may be aligned with and is fluidly coupled to a respective one of the first valve ports40and42and a respective one of the first actuator ports48and50. Each second actuator passage80,82in the first end station65is disposed between, may be aligned with and is fluidly coupled to a respective one of the first valve ports40and42and a respective one of the second actuator ports52and54. The first control valve24A may thereby control (e.g., regulate) fluid flow to and/or from and is dedicated to operation of both the first fluid actuator16A and the second fluid actuator16B.

When the valve body36is in the second end position ofFIG.3, the transfer valve26fluidly couples the second control valve24B to both the first fluid actuator16A and the second fluid actuator16B. Here, the first control valve24A is fluidly decoupled from both the first fluid actuator16A and the second fluid actuator16B. More particularly, each first actuator passage84,86in the second end station66is disposed between, may be aligned with and is fluidly coupled to a respective one of the second valve ports44and46and a respective one of the first actuator ports48and50. Each second actuator passage88,90in the second end station66is disposed between, may be aligned with and is fluidly coupled to a respective one of the second valve ports44and46and a respective one of the second actuator ports52and54. The second control valve24B may thereby control (e.g., regulate) fluid flow to and/or from and is dedicated to operation of both the first fluid actuator16A and the second fluid actuator16B.

The valve actuator38ofFIGS.1-3is configured to move the valve body36within the valve housing34between its various positions. Examples of the valve actuator38include, but are not limited to, an electric solenoid and an electric motor.

The controller28ofFIG.1is in signal communication (e.g., hardwired and/or wirelessly coupled) with the first control valve24A, the second control valve24B and the transfer valve26and its valve actuator38. The controller28may be implemented with a combination of hardware and software. The hardware may include a memory92and at least one processing device94, which processing device94may include one or more single-core and/or multi-core processors. The hardware may also or alternatively include analog and/or digital circuitry other than that described above.

The memory92is configured to store software (e.g., program instructions) for execution by the processing device94, which software execution may control and/or facilitate performance of one or more operations such as those described below. The memory92may be a non-transitory computer readable medium. For example, the memory92may be configured as or include a volatile memory and/or a nonvolatile memory. Examples of a volatile memory may include a random access memory (RAM) such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a synchronous dynamic random access memory (SDRAM), a video random access memory (VRAM), etc. Examples of a nonvolatile memory may include a read only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a computer hard drive, etc.

The fluid system10and its transfer valve26may be operated in various modes of operation. For example, when both the first control valve24A and the second control valve24B are (e.g., fully) operational, the fluid system10and its transfer valve26may operate in a multi-valve mode of operation; e.g., a normal operating mode. During this multi-valve mode of operation, the valve actuator positions the valve body36at its intermediate position where each control valve24A,24B is dedicated to and controls operation of a respective one of the fluid actuators16A,16B. Under certain conditions, however, one of the control valves24A and24B may malfunction or otherwise no longer operate as intended (e.g., be stuck open, be stuck closed, etc.). Where the second control valve24B is the non-operational control valve, the fluid system10and its transfer valve26may operate in a first single valve mode of operation; e.g., a first backup and/or emergency operating mode. During this first single valve mode of operation, the valve actuator28positions the valve body36at its first end position where the first control valve24A controls operation of both the first fluid actuator16A and the second fluid actuator16B. The transfer valve26may thereby operationally bypass the (e.g., non-operational) second control valve24B during the first single valve mode of operation. Similarly, where the first control valve24A is the non-operational control valve, the fluid system10and its transfer valve26may operate in a second single valve mode of operation; e.g., a second backup and/or emergency operating mode. During this second single valve mode of operation, the valve actuator38positions the valve body36at its second end position where the second control valve24B controls operation of both the first fluid actuator16A and the second fluid actuator16B. The transfer valve26may thereby operationally bypass the (e.g., non-operational) first control valve24A during the second single valve mode of operation.

With the foregoing arrangement, the multi-station transfer valve26may facilitate redundant control for each of the fluid actuators16without requiring inclusion of a separate back-up control valve for each fluid actuator16. However, when operating in the multi-valve mode of operation, each fluid actuator16A,16B may still be fine tuned and separately controlled by its respective dedicated control valve24A,24B. By contrast, a prior art system may include two separate electrohydraulic servo valves (EHSVs) dedicated to each fluid actuator, where one of the electrohydraulic servo valves is used as a backup to the other one of the electrohydraulic servo valves. The multi-station transfer valve26of the present disclosure may thereby reduce cost, weight and/or spatial requirements of the fluid system10.

FIG.4is a flow diagram of a method400for operating a fluid system. For ease of description, the operating method400is described below with reference to the fluid system10ofFIGS.1-3. The method400of the present disclosure, however, is not limited to operating such an exemplary fluid system.

In step402, the fluid system10and its transfer valve26are operated in the multi-valve mode of operation. The controller28ofFIG.1, for example, may signal the valve actuator38to position the valve body36at its intermediate position. The controller28may also signal the first control valve24A and the second control valve24B to selectively flow fluid to and/or from the first fluid actuator16A and the second fluid actuator16B to move (or hold a position of) the moveable component12.

In step404, the controller28monitors operation of the fluid system10. The controller28, for example, may receive one or more sensor signals indicative of the operation of the control valves24and/or one or more sensor signals indicative of the operation of the fluid actuators16. The controller28may then process data from the sensor signal(s) to determine if one or more of the control valves24is operating (e.g., opening, closing, holding its position, etc.) as expected. Where the control valves24are operating as expected, the fluid system10and its transfer valve26may continue to operate in the multi-valve mode of operation. However, where one of the control valves24A,24B is no longer operating as expected (e.g., the control valve24A,24B is non-operational, responding too slow, etc.), the operating method400may proceed to step406.

In the step406, the fluid system10and its transfer valve26are operated in one of the single valve modes of operation. For example, where it is determined the second control valve24B is no longer operating as expected, the controller28may signal the valve actuator38to move the valve body36to its first end position ofFIG.2. The fluid system10may thereby operationally bypass the (e.g., non-operational) second control valve24B and utilize the (e.g., operational) first control valve24A to control operation of the first fluid actuator16A and the second fluid actuator16B. By contrast, where it is determined the first control valve24A is no longer operating as expected, the controller28may signal the valve actuator38to move the valve body36to its second end position ofFIG.3. The fluid system10may thereby operationally bypass the (e.g., non-operational) first control valve24A and utilize the (e.g., operational) second control valve24B to control operation of the first fluid actuator16A and the second fluid actuator16B.

As described above, fluid flow through the transfer valve26may be restricted when the valve body36is in its intermediate position and operating in the multi-valve mode of operation. This restriction may limit an impact of fluid runaway if, for example, one of the control valves24malfunctions. However, fluid flow through the transfer valve26may be unrestricted when the valve body36is in its first and/or its second end position. The transfer valve26may thereby facilitate (e.g., full) operation of the first fluid actuator16A and the second fluid actuator16B even when regulated by the single control valve24.