Patent Application
20100240291
The present invention relates generally to aircraft systems and, more particularly, to position indication of an aircraft cabin pressure control system outflow valve.
Aircraft are commonly equipped with Cabin Pressure Control Systems (CPCSs), which maintain cabin air pressure within a desired range to increase passenger comfort during flight. A typical CPCS may include a controller, an actuator, and an outflow valve. The outflow valve is typically mounted on either a bulkhead of the aircraft or on the outer skin surface of the aircraft, and selectively fluidly couples the aircraft cabin and the atmosphere outside of the aircraft. During operation, the controller commands the actuator to move the outflow valve to various positions to control the rate at which pressurized air is transferred between the aircraft cabin and the outside atmosphere, to thereby control the pressure and/or rate of change of pressure within the aircraft cabin. The controller may be configured to command the actuator to modulate the outflow valve in accordance with a predetermined schedule or as a function of one or more operational criteria. For example, the CPCS may additionally include one or more cabin pressures to sense cabin pressure and supply pressure signals representative thereof to the controller. By actively modulating the outflow valve, the controller may maintain aircraft cabin pressure and/or aircraft cabin pressure rate of change within a desired range. Furthermore, the outflow valve may be positioned on the aircraft outer skin surface such that when pressurized air is exhausted from the cabin, the exhausted air may provide additional forward thrust to the aircraft. Thus, outflow valves may also be sometimes referred to as thrust recovery valves. Modern thrust recovery valves often contain two valve door elements to optimize the forward thrust that is created.
In addition to the above, some CPCSs include outflow valve position sensors to sense outflow valve position. The outflow valve position sensors, when included, typically provide only an indication of outflow valve position, and may be used for control and/or indication. In any case, when used on skin mounted thrust recovery valves containing two doors, the position sensors presently used are configured in a manner that valve position is only indirectly sensed. For example, the outflow valve position sensor may be mounted on the outflow valve actuator, and senses the position of an actuator component. The position of the outflow valve is then derived from the sensed actuator component position.
The above-described manner of sensing and determining outflow valve position, while generally safe, does suffer certain drawbacks. For example, because the outflow valve actuator may be a relatively complex device, with multiple motors and gear sets, variation from actuator to actuator may exist. Moreover, various linkages between the actuator output and the outflow valve doors may also exhibit further variations. As such, if the actuator is replaced, precise re-rigging of the replacement actuator to the proper position may be needed to prevent damage to the outflow valve and/or gears. Moreover, precise re-rigging of the replacement actuator may be needed to ensure the valve can meet a full-closed position and does not excessively leak. This re-rigging may take excessive production and/or maintenance time, with concomitantly excessive costs. Furthermore, the position sensing devices that are typically used may be relatively expensive and/or insufficiently robust.
Hence, there is a need for a method and means for sensing outflow valve position that is more accurate than what is presently done and/or does not rely on precise re-rigging of a replacement actuator and/or does not rely on relatively expensive or insufficiently robust position sensors. The present invention addresses one or more of these needs.
In one embodiment, and by way of example only, an aircraft cabin pressure control system outflow valve includes a frame, a valve element, and a position sensor. The frame is configured to be mounted on an aircraft exterior skin. The valve element is rotationally coupled to the frame, and is coupled to receive an actuation drive force. The valve element is responsive to the actuation drive force to rotate to a position between a closed position and a plurality of open positions. The position sensor is coupled to the frame and is configured to directly sense rotation of the valve element and supply a position signal representative of valve element position.
In another exemplary embodiment, an aircraft cabin pressure control system outflow valve includes a frame, an actuator, a first door, a second door, a first position sensor, and a second position sensor. The frame is configured to be mounted on an aircraft exterior skin. The actuator is coupled to the frame and is operable to supply an actuation drive force. The first door is rotationally coupled to the frame and is further coupled to receive the actuation drive force supplied by the actuator. The first door is responsive to the actuation drive force to rotate to a position between a closed position and a plurality of open positions. The second door is rotationally coupled to the frame and is further coupled to the first door. The second door is responsive to rotation of the first door to simultaneously rotate therewith to a position between a closed position and a plurality of open positions. The first position sensor is coupled to the frame and is configured to directly sense rotation of the first door and supply a position signal representative of first door position. The second position sensor is coupled to the frame and is configured to directly sense rotation of the second door and supply a position signal representative of second door position.
In still another exemplary embodiment, an aircraft cabin pressure control system includes a controller, an actuator, and an outflow valve. The actuator is coupled to receive actuation commands from the controller and is operable, in response thereto, to supply an actuation drive force. The outflow valve is coupled to receive the actuation drive force, and includes a frame, a valve element, and a position sensor. The frame is configured to be mounted on an aircraft exterior skin. The valve element is rotationally coupled to the frame, and is coupled to receive the actuation drive force. The valve element is responsive to the actuation drive force to rotate to a position between a closed position and a plurality of open positions. The position sensor is coupled to the frame and is configured to directly sense rotation of the valve element and supply a position signal representative of valve element position.
Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.
Turning first to
It will be appreciated that the controller 102 may command the actuator 104 to move the outflow valve 106 in accordance with a predetermined schedule or as a function of one or more sensed parameters. In the depicted embodiment, the CPCS 100 further includes one or more cabin pressure sensors 108 (only one shown for clarity) that sense pressure within the aircraft cabin 112 and supply a cabin pressure sensor signal representative thereof to the controller 102. It will additionally be appreciated that the CPCS 100 may be implemented with various other sensors, such as one or more non-illustrated cabin temperature sensors, one or more non-illustrated cabin-to-atmosphere differential pressure sensors, and one or more non-illustrated atmospheric temperature sensors, just to name a few.
The outflow valve 106 includes an inlet flow port 114, an outlet flow port 116, and an interposed valve element 118. The outflow valve 106 is, for example, preferably mounted on the aircraft exterior skin 122 such that the inlet flow port 114 is exposed to the aircraft cabin 112 and the outlet flow port 116 is exposed to the atmosphere outside of the aircraft 124. Thus, during flight the pressure in the aircraft cabin 112 (e.g., cabin altitude) and/or the rate of change of aircraft cabin altitude, can be controlled by positioning the valve element 118, via the actuator 104. In one specific implementation, the outflow valve 106 is located in the rear underbelly of the aircraft proximate the tail. Moreover, in some implementations, the outflow valve 106 may be positioned so that additional forward thrust is supplied to the aircraft when pressurized air is venting from the aircraft cabin 112 to the atmosphere 124 outside the aircraft. It will be appreciated that the outflow valve 106 may be variously configured to implement this functionality. One particular physical implementation will be described further below. Before doing so, however, the remainder of the CPCS 100 depicted in
The CPCS 100 additionally includes an outflow valve position sensor 126. The position sensor 126 is configured to directly sense movement of the variable area flow orifice 118, and supplies a position signal representative of variable area flow orifice position. In most embodiments, the position signal is supplied to one or more indicators 128 that provide a visual indication of variable area flow orifice position to an observer. In other embodiments, as shown in phantom in
Turning now to
The valve element 118, in response to the actuation drive force it receives from the actuator 104, rotates to a position between a closed position and a plurality of open positions. It is noted that the position of the valve element 118 during flight is typically a partially open position, intermediate the fully closed position (shown in
Before proceeding further, it was noted above that in some embodiments the outflow valve 106 may be located in the rear underbelly of the aircraft proximate the tail. Moreover, and as shown most clearly in
Returning once again to the description, and as shown more clearly in
As
For completeness of description, it is noted that when the valve element 118 is rotated into the fully open position (
The position sensors 126, as noted above, are coupled to the frame 202. As was also noted above, the position sensors 126 are configured to directly sense rotation of the valve element 118 and supply a position signal representative of valve element position. To do so, each position sensor 126 is preferably configured to sense rotation of one of the first valve pins 212 or one of the second valve pins 214. In the depicted embodiment, one position sensor 126 is coupled to the frame 202 and is configured to sense rotation of one of the first valve pins 212, and a second position sensor 126 is coupled to the frame 202 and is configured to sense rotation of one of the second valve pins 214. It will be appreciated that in other embodiments additional position sensors 126 may be coupled to the frame 202 so that rotation of each of the first valve pins 212 and each of the second valve pins 214 may be independently sensed.
No matter whether one or a plurality of position sensors 126 is used, each position sensor 126 may be implemented using any one of numerous position sensors now known or developed in the futures. For example, any one of numerous types of magnetic, optical, electromagnetic, electromechanical, and resistance type sensors may be used. In some embodiments, the position sensor 126 may include a moving element that is coupled to, or formed as an integral part of, the appropriate valve element pin 212 or 214, and a fixed sensing element that senses the rotation of the moving element. As one example of this, an exemplary magnetic position sensor 126 is depicted in cross section in
With reference now to
In addition to variations in the configurations of the valve pins 212, 214, the configuration of the valve itself may also vary. For example,
It is noted that in the embodiment depicted in
While described above in the context of an exemplary cabin pressure control system, it should be appreciated that embodiments of the outflow valve may be utilized in various other avionic and non-avionic applications where it is desirable to provide accurate, direct position indication of a valve element. In such alternative applications, the outflow valve may be utilized to regulate the flow of fluids other than pressurized air. Furthermore, although the above-described exemplary outflow valve employed two (i.e., forward and aft) rotatable doors, alternative embodiments of the outflow valve may include any suitable number of rotatable doors or other such valve elements.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.
