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EP-4159617-B1 - AIRCRAFT HYDRAULIC BRAKING SYSTEM AND METHOD OF CONTROLLING SAME

EP4159617B1EP 4159617 B1EP4159617 B1EP 4159617B1EP-4159617-B1

Inventors

  • HAYES, ALEXANDER
  • IBRAHIM, YASSER
  • PALITTA, MARICA
  • SIEGEL, ROMAIN

Dates

Publication Date
20260513
Application Date
20220930

Claims (13)

  1. An aircraft hydraulic braking system (100) comprising at least one hydraulic accumulator (150) and a brake actuator (15a-d); wherein the at least one hydraulic accumulator is the sole source of pressurised hydraulic fluid in the aircraft hydraulic braking system for operating the brake actuator; wherein the aircraft hydraulic braking system comprises at least one inlet (140) for receiving hydraulic fluid to charge the at least one hydraulic accumulator, wherein the aircraft hydraulic braking system is configured so that in-flight charging of the at least one hydraulic accumulator via the at least one inlet is precluded; and wherein the aircraft hydraulic braking system comprises a hydraulic fluid source (160) and is configured for charging the at least one accumulator from the hydraulic fluid source and via the at least one inlet between flights.
  2. The aircraft hydraulic braking system of claim 1, wherein the hydraulic fluid source comprises a hydraulic fluid reservoir (120) and a pump (P) for pumping hydraulic fluid from the hydraulic fluid reservoir to the at least one accumulator via the at least one inlet to charge the at least one accumulator.
  3. The aircraft hydraulic braking system of claim 2, wherein the pump is precluded from pumping hydraulic fluid from the hydraulic fluid reservoir to the at least one accumulator via the at least one inlet during flight of the aircraft.
  4. The aircraft hydraulic braking system of claim 2 or claim 3, wherein the pump is precluded from pumping hydraulic fluid from the hydraulic fluid reservoir to the at least one accumulator via the at least one inlet during a braking event of the aircraft.
  5. The aircraft hydraulic braking system of any one of claims 1 to 4, wherein the at least one accumulator comprises a first accumulator (150) and a second accumulator (250); and wherein the aircraft hydraulic braking system is configured to be operable in a first mode, in which the first accumulator is fluidically coupled to the brake actuator to operate the brake actuator, and a second mode, in which the second accumulator is fluidically coupled to the brake actuator to operate the brake actuator.
  6. The aircraft hydraulic braking system of claim 5, comprising a second brake actuator (15c), wherein: in the first mode, the second accumulator is fluidically coupled to the second brake actuator to operate the second brake actuator; and/or in the second mode, the second accumulator is fluidically coupled to the second brake actuator to operate the second brake actuator.
  7. A method (300) of controlling a hydraulic braking system (100) of an aircraft (1), the hydraulic braking system comprising a brake actuator (15a) and at least one hydraulic accumulator (150), wherein the at least one hydraulic accumulator is the sole source of pressurised hydraulic fluid in the hydraulic braking system for operating the brake actuator, the method comprising: precluding charging of the at least one hydraulic accumulator during a flight of the aircraft; causing at least partial discharge of the at least one hydraulic accumulator to operate the brake actuator during the flight or during a landing event at an end of the flight; and causing charging of the at least one hydraulic accumulator while the aircraft is on the ground before the flight, wherein the causing charging comprises causing charging of the at least one hydraulic accumulator from a hydraulic fluid source (160) of the hydraulic braking system.
  8. The method of claim 7, comprising precluding charging of the at least one hydraulic accumulator during the causing at least partial discharge of the hydraulic accumulator.
  9. An aircraft braking system controller (500) configured to operate the aircraft hydraulic braking system (100) of any one of claims 1 to 6 to carry out the method of claim 7 or claim 8
  10. The aircraft hydraulic braking system of any one of claims 1 to 6, comprising the aircraft braking system controller of claim 9.
  11. A non-transitory computer-readable storage medium (400) storing instructions that, when executed by a processor (420) of an aircraft braking system controller (500), cause the processor to operate the aircraft hydraulic braking system (100) of any one of claims 1 to 6 or claim 10 to carry out the method (300) of claim 7 or claim 8.
  12. A braking system for an aircraft (1), the braking system comprising a first hydraulic braking system (100a) and a second hydraulic braking system (100b), wherein the first hydraulic braking system comprises a first supply of hydraulic fluid (150) and is configured to brake a first wheel (11a) of the aircraft, and the second hydraulic braking system comprises a second supply of hydraulic fluid (250) and is configured to brake a second wheel (11b) of the aircraft; and wherein the braking system is free from any fluidic connection between the first and second hydraulic braking systems, and wherein the first hydraulic braking system and/or the second hydraulic braking system comprises the aircraft hydraulic braking system of any one of claims 1 to 6, or claim 10.
  13. An aircraft (1) comprising the aircraft hydraulic braking system (100) of any one of claims 1 to 6 or claim 10, the aircraft braking system controller (500) of claim 9, the non-transitory computer-readable storage medium (400) of claim 11, or the braking system of claim 12.

Description

TECHNICAL FIELD The present invention relates to braking systems for aircraft, particularly aircraft hydraulic braking systems, methods of and controllers for controlling the same, and aircraft comprising the braking systems and/or hydraulic braking systems. BACKGROUND Aircraft braking systems typically comprise one or more primary energy sources, such as pumps, for operating plural brakes of an aircraft, such as to slow the aircraft during a landing event on a runway. Some aircraft braking systems also comprise backup, or alternative, sources of pressurised hydraulic fluid for operating the brakes, such as hydraulic accumulators. These may be used to operate the brakes in the event of a failure of the one or more primary energy sources. CN 108284947 A discloses an airplane braking system based on pressure storage and energy storage for an aircraft on which an airborne hydraulic/pneumatic system has been replaced. DE 1072103 B discloses a braking device having an accumulator that replaces a pressure supply system. US 5411323 A discloses an automatic brake control apparatus that can use an accumulator in an emergency brake apparatus. US 3948569 A discloses a hydraulic accumulator that provides pressurised liquid to hydraulic actuators of a stack of carbon discs. GB 598383 A discloses a pressure accumulator that supplies oil to pressure regulating valves of wheel brakes. The present invention aims to provide improved aircraft braking systems which are lighter, less complex and/or more efficient than known aircraft braking systems. SUMMARY A first aspect of the present invention provides an aircraft hydraulic braking system comprising at least one hydraulic accumulator and a brake actuator. The at least one hydraulic accumulator is the sole source of pressurised hydraulic fluid in the aircraft hydraulic braking system for operating the brake actuator. The aircraft hydraulic braking system comprises at least one inlet for receiving hydraulic fluid to charge the at least one hydraulic accumulator, wherein the aircraft hydraulic braking system is configured so that in-flight charging of the at least one hydraulic accumulator via the at least one inlet is precluded. The aircraft hydraulic braking system also comprises a hydraulic fluid source and is configured for charging the at least one accumulator from the hydraulic fluid source and via the at least one inlet between flights. Providing the at least one hydraulic accumulator as the sole source of hydraulic fluid for operating the brake actuator may reduce a weight and/or complexity of the aircraft hydraulic braking system, such as by reducing a number of components and/or fluid connections in the aircraft hydraulic braking system, or between the aircraft hydraulic braking system and other hydraulic systems of the aircraft. For example, the aircraft hydraulic braking system need not be fluidically connected or connectable to a centralised hydraulic system of the aircraft. Indeed, such a centralised hydraulic system could be omitted from the aircraft. Optionally, the aircraft hydraulic braking system is free from plural hydraulic accumulators fluidically connected in series. This may similarly reduce a weight and/or complexity of the aircraft hydraulic braking system, such as by reducing a number of components and/or fluid connections in the aircraft hydraulic braking system. Precluding in-flight charging of the at least one hydraulic accumulator may improve an in-flight reliability of the aircraft hydraulic braking system, such as by reducing a number of components and/or fluid connections that would otherwise be required to charge the at least one hydraulic accumulator in-flight, and/or by reducing a number of operations performed in-flight, such operations including charging the at least one hydraulic accumulator. Moreover, precluding in-flight charging of the at least one hydraulic accumulator may avoid a need to certify a charging system for operation during a flight. By providing the hydraulic fluid source, the at least one accumulator may be charged when the aircraft is on the ground, such as during taxiing or loading, without requiring connection to an external source of hydraulic fluid. Optionally, the hydraulic fluid source comprises a hydraulic fluid reservoir and a pump for pumping hydraulic fluid from the hydraulic fluid reservoir to the at least one accumulator via the at least one inlet to charge the at least one accumulator. Optionally, the pump is precluded from pumping hydraulic fluid from the hydraulic fluid reservoir to the at least one accumulator via the at least one inlet during flight of the aircraft. The hydraulic fluid reservoir may be configured to receive hydraulic fluid from the brake actuator during actuation of the actuator. This may be by the hydraulic braking system comprising one or more return lines and/or valves configured to return fluid from the brake actuator to the hydraulic fluid reservoir. This may allow the hydraulic flu