Cabin pressure thrust recovery outflow valve with single door

A single valve door thrust recovery outflow valve is provided that does not rely on a relatively large and expensive actuator to move it, and does not create unwanted drag during aircraft cruise operations. The valve includes a valve frame, a valve door, and an aerodynamic flap. The valve door is rotationally coupled to the valve frame, is adapted to receive a drive torque, and is configured, upon receipt of the drive torque, to rotate between a closed position, a full-open position, and a plurality of partial-open positions between the closed position and the full-open position. The aerodynamic flap is coupled to the valve door. When the valve door is in the closed position and in numerous partial-open positions, the aerodynamic flap makes the thrust recovery outflow valve aerodynamically clean.

TECHNICAL FIELD

The present invention generally relates to aircraft cabin pressure thrust recovery systems, and more particularly relates to a cabin pressure thrust recovery outflow valve.

BACKGROUND

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 pressure sensors 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.

In some aircraft, 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 sometimes be referred to as thrust recovery valves. Modern thrust recovery valves often include two valve door elements with multiple actuation linkages to enable proper sealing, reduce drag, and optimize valve door positioning for cruise thrust creation. Some earlier thrust recovery valves include a single, scoop-type valve door. These single valve doors are typically hinged on an end of the trailing edge. While this configuration makes the valve door aerodynamically acceptable, it can also make the actuation torque needed to drive the valve undesirably large. This, in turn, can result in relatively large and relatively expensive actuators and drive linkages being used.

Single valve door thrust recovery valves with the hinge point midway on the valve door, to thereby reduce the drive torque, have been envisioned. Unfortunately, these single valve door thrust recovery valves exhibit certain drawbacks. For example, in order to move the valve to the positions necessary to both seal and to not protrude during aircraft cruise operations, the valve door must be located inboard of the fuselage skin, which creates unwanted drag.

Hence, there is a need for a single valve door thrust recovery valve that does not rely on a relatively large and expensive actuator to move it, and/or does not create unwanted drag during aircraft cruise operations. The present invention addresses at least these needs.

BRIEF SUMMARY

In one embodiment, an aircraft cabin pressure control system thrust recovery outflow valve includes a valve frame, a valve door, and an aerodynamic flap. The valve frame is configured to be mounted on an aircraft exterior skin, and includes an inner surface, an outer surface, a forward seat, and an aft seat. The inner surface defines a flow passage through the valve frame. The valve door is rotationally coupled to the valve frame, and includes a leading edge, a trailing edge, and two side edges. The valve door is adapted to receive a drive torque and configured, upon receipt of the drive torque, to rotate between a closed position, a full-open position, and a plurality of partial-open positions between the closed position and the full-open position. The aerodynamic flap includes a first end and a second end. The first end is coupled to the valve door, and the second end is biased toward the trailing edge of the valve door.

In another embodiment, an aircraft cabin pressure control system thrust recovery outflow valve includes a valve frame, a valve door, and an aerodynamic flap. The valve frame is configured to be mounted on an aircraft exterior skin, and includes an inner surface, an outer surface, a forward seat, and an aft seat. The inner surface defines a flow passage through the valve frame. The valve door is rotationally coupled to the valve frame, and includes a leading edge and a trailing edge. The valve door is adapted to receive a drive torque and is configured, upon receipt of the drive torque, to rotate between a closed position, a full-open position, and a plurality of partial-open positions between the closed position and the full-open position. The aerodynamic flap includes a first end and a second end. The first end is coupled to the valve door, and the second end is biased toward the trailing edge of the valve door. The valve frame and valve door are configured such that: (1) when the valve door is in the closed position, the leading edge of the valve door engages the forward seat of the valve frame, and the trailing edge of the valve door engages the aft seat of the valve frame; (2) when the valve door is in any open position, the leading edge of the valve door does not engage the forward seat of the valve frame; (3) when the valve door is between the closed position and a predetermined partial-open position, the trailing edge of the valve door engages the aft seat of the valve frame; and (4) when the valve door is between the predetermined partial-open position and the full-open position, the trailing edge of the valve door does not engage the aft seat of the valve frame.

Furthermore, other desirable features and characteristics of the cabin pressure control system thrust recovery outflow valve will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.

DETAILED DESCRIPTION

Turning first toFIG. 1, a simplified block diagram of an exemplary aircraft cabin pressure control system (CPCS)100is depicted. In the depicted embodiment, the CPCS includes a controller102, an actuator104, and a thrust recovery outflow valve106. The controller102is operatively (e.g., electrically) coupled to the actuator104, which is, in turn, mechanically coupled to the thrust recovery outflow valve106. During operation of the CPCS100, the controller102commands the actuator104to move the thrust recovery outflow valve106to various positions, to thereby modulate cabin pressure and/or cabin pressure rate-of-change.

It will be appreciated that the controller102may command the actuator104to move the thrust recovery outflow valve106in accordance with a predetermined schedule or as a function of one or more sensed parameters. In the depicted embodiment, the CPCS100further includes one or more cabin pressure sensors108(only one shown for clarity) that sense pressure within the aircraft cabin112and supply a cabin pressure sensor signal representative thereof to the controller102. It will additionally be appreciated that the CPCS100may 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, one or more non-illustrated atmospheric temperature sensors, and one or more outflow valve position sensors, just to name a few.

The thrust recovery outflow valve106includes an inlet flow port114, an outlet flow port116, and an interposed valve118. The thrust recovery outflow valve106is, for example, preferably mounted on the aircraft exterior skin122such that the inlet flow port114is exposed to the aircraft cabin112and the outlet flow port116is exposed to the atmosphere outside of the aircraft124. Thus, during flight, the pressure in the aircraft cabin112(e.g., cabin altitude) and/or the rate of change of aircraft cabin altitude, can be controlled by positioning the valve element118, via the actuator104. In one specific implementation, the thrust recovery outflow valve106is located in the rear underbelly of the aircraft proximate the tail. Moreover, in some implementations, the thrust recovery outflow valve106may be positioned so that additional forward thrust is supplied to the aircraft when pressurized air is venting from the aircraft cabin112to the atmosphere124outside the aircraft. It will be appreciated that the thrust recovery outflow valve106may be variously configured to implement this functionality. One particular physical implementation is depicted inFIGS. 2 and 3, and with reference thereto will now be described.

The exemplary physical implementation of the thrust recovery outflow valve106includes a valve frame202, the valve element118, and the actuator104. The valve frame202is configured to be mounted on the aircraft exterior skin122, and includes an inner surface204, an outer surface208, a forward seat212, and an aft seat214. The inner surface204defines a flow passage302(seeFIG. 3) through the valve frame202between the inlet flow port114and the outlet flow port116. AsFIG. 2also depicts, the valve frame202may additionally include a first side seat216, a second side seat218, and a plurality of fastener openings222. The first and second side seats216,218both extend between the forward and aft seats212,214, and the fastener openings222are used to secure the thrust recovery outflow valve106to the aircraft exterior skin122. It will be appreciated that the depicted shapes and configurations of the forward seat212, the aft seat214, and the first and second side seats216,218are merely exemplary of one embodiment, and that the shapes and configurations thereof may vary.

The valve element118includes a valve door224and, as shown most clearly inFIG. 3, an aerodynamic flap304. The valve door224is rotationally coupled to the valve frame202, and includes a leading edge226, a trailing edge228, a first side232, a second side306(seeFIG. 3), and two side edges—a first side edge234and a second side edge236(not fully visible inFIG. 2). Although the manner in which the valve door224is rotationally coupled to the valve frame202may vary, in the depicted embodiment the valve door224is rotationally coupled to the valve frame202via a plurality of hinges238(only one visible inFIG. 2). Preferably, the hinges238are disposed in hinge mounts242on the valve frame202and valve door224. The hinge mounts242are preferably located such that any applied torque that closes the valve door224will overcome any applied torque that opens the valve door224. The applied torque may be from a multitude of sources, including aerodynamic or cabin-to-ambient differential pressure loading. The location of the hinge mounts242can be optimized to balance the applied closing and opening torque, while still ensuring that the applied closing torque overcomes the applied opening torque, so that the location of the hinge mounts242also reduces the amount of torque that the actuator104needs to supply to the valve door224.

The valve door224is coupled to receive a drive torque from the actuator104and is configured, upon receipt of the drive torque, to rotate between a closed position, a full-open position, and a plurality of partial-open positions between the closed position and the full-open position. In the closed position, which is the position depicted inFIGS. 2 and 3, the valve door224is disposed at a non-zero angle (α) relative to the inlet flow port114. The reason for this will become apparent when the operation of the valve element118is described further below.

To provide sufficient sealing between the valve door224and the aft seat214and the first and second side seats216,218, one or more seals301(seeFIG. 3) are preferably coupled to the valve door224. The seals301may be coupled to the first side232of the valve door224, adjacent the trailing edge228and the first and second side edges234,236. Alternatively, non-illustrated seal grooves may be formed in the trailing edge228and the first and second side edges234,236, and the one or more seals301may be disposed within these grooves. No matter the specific manner of coupling the one or more seals301to the valve door224, the one or more seals301engage the valve frame202, and more specifically the aft seat214and the first and second side seats216,218, when the valve element118is in the closed position and, as will be described in more detail further below, in a plurality of partial-open positions.

The valve door224may also be implemented with various other structural features. For example, the depicted valve door224includes a plurality of structural ribs244, and a bellmouth structure246. The structural ribs244, if included, are formed on the valve door first side232, which is the side that faces the interior of the aircraft, and provide added structural strength to the valve door224. The structural ribs244may, at least in some embodiments, be hollow. The bellmouth structure246comprises, or is otherwise coupled to, the leading edge226of the valve door224. The bellmouth structure246, if included, is preferably curved and is configured to condition fluid flow through the thrust recovery outflow valve106, to optimize thrust and reduce flow noise, when the valve element118is in an open position. The valve door224is preferably manufactured from any one of numerous non-metallic composite materials, thereby exhibiting a relatively light weight. It will be appreciated that numerous metallic materials could also be used.

The aerodynamic flap304includes a first end308, which is coupled to the second side306of the valve door224, and a second end312, which is biased toward the trailing edge228of the valve door224. In one embodiment, the first end308of the aerodynamic flap304is rotationally coupled to the valve door second side306. In this embodiment, the valve element118additionally includes a spring402. The spring402, as depicted inFIG. 4, is coupled between the valve door224and the aerodynamic flap304and may, for example, extend through one of the structural ribs244. The spring402provides the bias force that urges the second end312of the aerodynamic flap304toward the trailing edge228of the valve door224. In this embodiment, the valve door224and aerodynamic flap304are also configured to implement a stop feature502. The stop feature502, which is depicted most clearly inFIG. 5, limits rotation of the aerodynamic flap304in the unlikely event the spring402were to be rendered inoperable.

In another embodiment, the first end308of the aerodynamic flap304is non-rotationally coupled to the valve door second side306. In this embodiment, which is depicted inFIG. 6, the aerodynamic flap304comprises a flexible material that has sufficient elasticity to exhibit natural spring characteristics. As such, the aerodynamic flap304would itself bias its second end312toward the trailing edge228of the valve door224.

As noted above, the actuator104supplies the drive torque to, and thus positions, the valve door224. Although the specific configuration, implementation, and location of the actuator104may vary, in the depicted embodiment the actuator104is preferably implemented using an electric rotary actuator, and is preferably disposed over, and spaced apart from, the first side232of the valve door224. Most preferably, the actuator104is disposed over the aft half of the valve door224, which provides compactness and aids in actuator installation. The actuator104is also preferably coupled to the first side232of the valve door224via a plurality of links. In the depicted embodiment, this includes a door link248, a drive link252, and a secondary link254. The door link248is fixedly coupled to, and extends perpendicular from, the first side232of the valve door224. The drive link252is coupled to the actuator104to receive the drive torque therefrom, and the secondary link254is coupled between the drive link252and the door link248to transfer the drive torque from the actuator104to the valve door224.

With reference now toFIGS. 7-9, operation of the valve element118will be described. When the valve element118is in the closed position, which is the position depicted inFIG. 7, the leading edge226of the valve door224contacts the forward seat212of the valve frame202, and the trailing edge228of the valve door224contacts, via the one or more seals301, the aft seat214near its top. Thus, as noted above, the valve door224is disposed at a non-zero angle (α) relative to the inlet flow port114. In addition, the second end312of the aerodynamic flap304engages the valve frame202and, when installed in an aircraft, the aircraft exterior skin122.

Upon receiving an appropriate drive torque from the actuator104, the valve element118may be moved to the full-open position or to a partial-open position. As shown most clearly inFIG. 8, the valve element118may be moved to a plurality of partial-open positions in which the leading edge226of the valve door224does not contact the forward seat212while, at the same time, the trailing edge228of the valve door224continues to contact, via the seal301, the aft seat214, and the second end312of the aerodynamic flap304continues to engage the aircraft exterior skin122. Thus, the valve element118may be moved between the closed position and a predetermined partial-open position, which is the position depicted inFIG. 8, without the trailing edge228of the valve door224extending beyond the perimeter of the aircraft exterior skin122and creating drag. This allows the valve element118to be moved to any one of numerous partial-open positions during flight operations without creating unwanted drag.

If, as depicted inFIG. 9, the valve element118is moved beyond the predetermined partial-open position, the valve door224engages the aerodynamic flap304and these two elements move together. It is noted that the position depicted inFIG. 9is the full-open position. It is additionally noted that the valve element118is preferably moved beyond the predetermined partial-open position only during ground operation, just after aircraft takeoff, or just before aircraft landing.

From the above, the following may be readily apparent: (1) when the valve element118is in the closed position, the leading edge226of the valve door224engages the forward seat212of the valve frame202, and the trailing edge228of the valve door224engages the aft seat214of the valve frame202; (2) when the valve element118is in any open position, the leading edge226of the valve door224does not engage the forward seat212of the valve frame202; (3) when the valve element118is between the closed position and the predetermined partial-open position, the trailing edge228of the valve door224engages the aft seat214of the valve frame202; (4) when the valve element118is between the predetermined partial-open position and the full-open position, the trailing edge228of the valve door224does not engage the aft seat214of the valve frame202; and (5) the second end312of the aerodynamic flap304engages the valve frame202and/or aircraft exterior skin122except when the valve element118is between the predetermined partial-open position and the full-open position. Thus, between the closed position and the predetermined partial-open position, the aerodynamic flap304makes the thrust recovery outflow valve106aerodynamically “clean,” and the flow angle is optimized at least through the initial valve stroke.