Abstract: The disclosure is directed to an independent manual control system of an all-electric cabin pressure control system (CPCS). The manual control system may include a momentary electrical switch to manually set the position of an outflow valve (OFV) along with a closed loop control to hold the cabin pressure at the pressure setpoint. The closed loop control of the manual control system is independent from the automatic pressure control functions of the all-electric CPCS.

Abstract: In some examples, a cabin pressure control and monitoring system includes an outflow valve and a manual control panel comprising a selector switch and configured to generate a signal, wherein a value encoded in the signal is dependent on a position of the selector switch. The cabin pressure control and monitoring system also includes a controller configured to receive the signal from the manual control panel, determine a target rate of change for a cabin pressure based on the value encoded in the signal, and control the outflow valve based on the target rate of change.

Abstract: A pressure control system includes an overboard valve in indirect communication with a first enclosed environment and in direct communication with a second enclosed environment. The first environment is suitable for human occupancy and configured to receive pressurized air from an environmental control system. The second environment is configured to receive the pressurized air from the first environment. An inboard valve is configured to supply a discharge of pressurized air from the second environment. An outflow valve is configured to regulate a discharge of air from the first environment to an area outside the first and second environments. A positive pressure relief valve configured to regulate a discharge of air from the first environment. A negative pressure relief valve configured to regulate an ingress of air into the first environment. A control valve is configured to regulator and supply pressurized air from the first environment to a compressor.

Abstract: The disclosure is directed to an independent manual control system of an all-electric cabin pressure control system (CPCS). The manual control system may include a momentary electrical switch to manually set the position of an outflow valve (OFV) along with a closed loop control to hold the cabin pressure at the pressure setpoint. The closed loop control of the manual control system is independent from the automatic pressure control functions of the all-electric CPCS.

Abstract: A system of pressure control for an environment to be pressurized includes a controller configured to calculate an environment leakage effective area CdALEAK according to: CdALEAK=f(Pc, Tc, Pa, WLEAK) wherein Pc is an environment pressure; Tc is an environment temperature; Pa is an ambient pressure outside of the environment; WLEAK=WECS?WOFV?WAPU; wherein WECS=air pressure inflow into the environment; WOFV=air pressure outflow to ambient that is outside of the environment; WAPU=f(Tin, Pin, APURPM, Flowfuel); wherein Tin=inlet temperature to a power source; Pin=inlet pressure to the power source; APURPM=rotational speed of the power source; Flowfuel=power source fuel flow. A processor is in communication with the controller and configured to compare a current CdALEAK value with a control limit; wherein the control limit is based on historical CdALEAK values.

Abstract: A pressure control system includes an overboard valve in indirect communication with a first enclosed environment and in direct communication with a second enclosed environment. The first environment is suitable for human occupancy and configured to receive pressurized air from an environmental control system. The second environment is configured to receive the pressurized air from the first environment. An inboard valve is configured to supply a discharge of pressurized air from the second environment. An outflow valve is configured to regulate a discharge of air from the first environment to an area outside the first and second environments. A positive pressure relief valve configured to regulate a discharge of air from the first environment. A negative pressure relief valve configured to regulate an ingress of air into the first environment. A control valve is configured to regulator and supply pressurized air from the first environment to a compressor.

Abstract: A system of pressure control for an environment to be pressurized includes a controller configured to calculate an environment leakage effective area CdALEAK according to: CdALEAK=f(Pc, Tc, Pa, WLEAK) wherein Pc is an environment pressure; Tc is an environment temperature; Pa is an ambient pressure outside of the environment; WLEAK=WECS?WOFV?WAPU; wherein WECS=air pressure inflow into the environment; WOFV=air pressure outflow to ambient that is outside of the environment; WAPU=f(Tin, Pin, APURPM, Flowfuel); wherein Tin=inlet temperature to a power source; Pin=inlet pressure to the power source; APURPM=rotational speed of the power source; Flowfuel=power source fuel flow. A processor is in communication with the controller and configured to compare a current CdALEAK value with a control limit; wherein the control limit is based on historical CdALEAK values.

Abstract: A multiple outflow valve control system for an aircraft is provided having a plurality of outflow valves that may be controlled independently via an all electrical control system. The outflow valves may be located in various locations in an aircraft. The control system may have a control loop controlling the outflow valve motors via open-loop PWM commands and may not have a motor speed feedback in the control loop. The cabin pressure control system may have manual and auto controls controlling separate motors on each outflow valve. Auto motor control may be performed via software biasing command logic included in the control laws in the control system. Air flow may be biased through selected outflow valves and the degree of biasing may be automatically or manually set.

Abstract: A method of calibrating an outflow valve on an aircraft may include determining if the aircraft has reached a predetermined cruise condition. The outflow valve may be moved until a closed position is reached, if the aircraft has reached the predetermined cruise condition. An actual position feedback value of the outflow valve may be determined while the aircraft is in the predetermined cruise condition. An offset calibration factor may be determined from the actual position feedback value of the outflow valve relative to a theoretical value.

Abstract: A method of calibrating an outflow valve on an aircraft may include determining if the aircraft has reached a predetermined cruise condition. The outflow valve may be moved until a closed position is reached, if the aircraft has reached the predetermined cruise condition. An actual position feedback value of the outflow valve may be determined while the aircraft is in the predetermined cruise condition. An offset calibration factor may be determined from the actual position feedback value of the outflow valve relative to a theoretical value.

Abstract: A multiple outflow valve control system for an aircraft is provided having a plurality of outflow valves that may be controlled independently via an all electrical control system. The outflow valves may be located in various locations in an aircraft. The control system may have a control loop controlling the outflow valve motors via open-loop PWM commands and may not have a motor speed feedback in the control loop. The cabin pressure control system may have manual and auto controls controlling separate motors on each outflow valve. Auto motor control may be performed via software biasing command logic included in the control laws in the control system. Air flow may be biased through selected outflow valves and the degree of biasing may be automatically or manually set.

Abstract: A cabin pressure control system and method improves cabin pressurization during aircraft take-off operations. The cabin pressure control system sets a cabin pressurization rate limit based on a cabin pressurization rate error. The cabin pressurization rate error is derived from a comparison of a sensed cabin pressure rate-of-change value and a predetermined cabin pressurization rate value.

Abstract: A cabin pressure control system and method that reduces or inhibits gear train backlash and the concomitant cabin pressure oscillations associated therewith. The cabin pressure control system includes a variable proportional-integral (PI) controller that implements a proportional function with a variable gain term and an integrator function with variable saturation limit. The proportional function gain term is increased, and the integrator saturation limits are decreased, at relatively low cabin error rate magnitudes. Increasing the proportional function gain term at relatively low cabin error rate magnitudes offsets potential backlash effects from the gear train. Decreasing the integrator saturation limits at relatively low cabin rate error magnitudes reduces potentially excessive integrator wind-up levels, which reduces the likelihood of producing limit-cycling and the potential for cabin pressure oscillations.

Abstract: An aircraft cabin pressure control system and the method implement a technique that oversamples and filters a sensed cabin pressure signal, and then differentiates the oversampled and filtered pressure signal to generate cabin pressure rate-of-change. The oversampling and filtering technique removes circuit and sensor induced noise from the cabin pressure signal, and results in cabin pressure rate-of-change values with less noise than currently known systems and methods.

Abstract: A pressure control system including an inflow unit for admitting pressurized air into a cabin, an outflow unit including a motor for operating a valve to discharge air from the cabin at a predetermined rate based on an motor control signal that sets the motor speed, a control unit, and an air pressure sensor within the cabin for determining a pressure signal. The control unit receives the pressure signal and computes a pressure rate of change error signal to set the motor control signal. The outflow unit, control unit, and air pressure sensor form a feedback control loop independent of motor speed, valve speed, or valve position feedback.