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EP-4582344-B1 - METHOD FOR MONITORING AN OPERATION OF A ROTORCRAFT POWER PLANT AND ASSOCIATED ROTORCRAFT

EP4582344B1EP 4582344 B1EP4582344 B1EP 4582344B1EP-4582344-B1

Inventors

  • MILLET, Arnaud
  • DUMUR, GUILLAUME

Dates

Publication Date
20260513
Application Date
20241016

Claims (13)

  1. Method (30, 40) for monitoring an operation of a rotorcraft (1) engine installation (2), said engine installation (2) comprising at least one engine (3, 4), said rotorcraft (1) comprising at least one lift rotor (5) rotated by said engine installation (2), said monitoring method (30, 40) comprising the following steps: - detection (31, 41) of a regulation breakdown (PAN) affecting a regulation system (13, 14) of said at least one engine (3, 4), - detection (32, 42) of a current rotation speed (NR) of said at least one lift rotor (5), - determination (33, 43) of a compatibility condition (COMP) or of an incompatibility condition (INCOMP) between a current flight phase and said rotation speed (NR), characterised in that said monitoring method (30, 40) comprises the following steps: - in a first operating mode (MOD1), in the presence of said compatibility condition (COMP) and of said regulation breakdown (PAN), generation (34, 44) of a first alert, simultaneously representative of said regulation breakdown (PAN) and of said compatibility condition (COMP), and - in a second operating mode (MOD2), in the presence of said incompatibility condition (INCOMP) and of said regulation breakdown (PAN), generation (35, 45) of a second alert, simultaneously representative of said regulation breakdown (PAN) and of said incompatibility condition (INCOMP).
  2. Method according to claim 1, characterised in that said compatibility condition (COMP) is determined when said current rotation speed (NR) belongs to a value interval defined by a rotation speed setpoint (NRcons) less a first margin (n) and said rotation speed setpoint (NRcons) plus a second margin (m) and alternatively, said incompatibility condition (INCOMP) is determined, when said current rotation speed (NR) is excluded from said value interval.
  3. Method according to claim 2, characterised in that said rotation speed setpoint (NRcons) is variable as a function of said current flight phase.
  4. Method according to any one of claims 2 to 3, characterised in that said first margin (n) and said second margin (m) are variable as a function of said current flight phase.
  5. Method according to claim 1, characterised in that said compatibility condition (COMP) is determined when said current rotation speed (NR) belongs to a predetermined range of acceptable values, making it possible to continue said current flight phase, and alternatively, said incompatibility condition (INCOMP) is determined, when said current rotation speed (NR) is excluded from said predetermined range of acceptable values, making it possible to continue said current flight phase.
  6. Method according to claim 5, characterised in that said predetermined range comprises a defined upper limit, such that a vane end tangential speed of a vane (12) of said at least one lift rotor (5) is maintained less than the speed of sound.
  7. Method according to any one of claims 5 to 6, characterised in that said predetermined range comprises a defined lower limit to provide a minimal thrust, making it possible for said rotorcraft (1) to fly at a constant altitude, at a forward cruise speed.
  8. Method according to any one of claims 1 to 7, characterised in that a passage from said first operating mode (MOD1) to said operating mode (MOD2) is irreversible.
  9. Method according to any one of claims 1 to 8, characterised in that said generation (34, 44) of the first alert comprises a first display (341, 441) on a display unit (10) of at least one piece of information represented with a first predetermined colour.
  10. Method according to claim 9, characterised in that said generation (35, 45) of the second alert comprises a second display (351, 451) on said display unit (10) of said at least one piece of information represented with a second predetermined colour, different from said first predetermined colour.
  11. Method according to any one of claims 1 to 10, characterised in that , said at least one engine (3, 4) comprising a first engine (3) and a second engine (4), said regulation breakdown (PAN) affecting a first regulation system (13) of said first engine (3), when said second alert is generated, the method (30) comprises a control (36) of a stopping of said first engine (3).
  12. Method according to any one of claims 1 to 10, characterised in that , said at least one engine (3, 4) comprising a first engine (3) and a second engine (4), said regulation breakdown (PAN) affecting a first regulation system (13) of said first engine (3), when said second alert is generated, the method (40) comprises a control (46) of a reversible transmission device, to prevent the transmission of an engine torque of said first engine (3) to a power transmission chain (11).
  13. Rotorcraft (1) comprising at least one lift rotor (5), rotated by an engine installation (2), said engine installation (2) comprising at least one engine (3, 4) said rotorcraft (1) comprising a monitoring system (6) comprising: - at least one breakdown sensor (23, 24) detecting a regulation breakdown (PAN) affecting a regulation system (13, 14) of said at least one engine (3, 4), - a speed sensor (7) measuring a current rotation speed (NR) of said at least one lift rotor (5), - a controller (8) determining a compatibility condition (COMP) or an incompatibility condition (INCOMP) between a current flight phase and said rotation speed (NR), characterised in that said controller (8) generates, in a first operating mode (MOD1), in the presence of said compatibility condition (COMP) and of said regulation breakdown (PAN), a first alert, simultaneously representative of said regulation breakdown (PAN) and of said compatibility condition (COMP), and and in that said monitoring controller (8) generates, in a second operating mode (MOD2), in the presence of said incompatibility condition (INCOMP) and of said regulation breakdown (PAN), a second alert, simultaneously representative of said regulation breakdown (PAN) and of said incompatibility condition (INCOMP).

Description

The present invention relates to a method for monitoring the operation of a rotorcraft propulsion system. A rotorcraft has at least one rotor that contributes to its lift, or even its propulsion. For example, a rotorcraft may include a main rotor that contributes to its lift and propulsion, this main rotor having blades with collectively and cyclically variable pitch. In addition, the rotorcraft may include a system that contributes to yaw control, such as another main rotor or a tail rotor. The pitch control system can be activated, for example, by the pilot or crew. Alternatively, the system can be activated by an automatic control system, known as an autopilot. To rotate the rotor(s), the rotorcraft includes a propulsion system, possibly multi-engine, and a power transmission chain going from the engines to one or more rotors. For example, two motors are connected to a power transmission unit, which rotates the rotor(s). The power transmission unit then has one mechanical input per motor, with the mechanical inputs meshing with a combiner, the combiner driving one mechanical output of the power transmission unit per rotor. The motor inputs, the combiner, and the mechanical outputs can include at least one pinion or gear, at least one shaft, at least one speed reduction stage, etc. Engines can be internal combustion engines with an output shaft set in motion by the combustion of fuel. For example, at least one engine can be a turboshaft engine equipped with a gas generator and a free-working turbine connected to the output shaft. Each engine can be controlled by a control system known by the acronym FADEC and the English expression "Full Authority Digital Engine Control". Such a control system includes an engine computer in communication with sensors measuring operating parameter values of the controlled engine, or even of the rotorcraft, such as the rotational speed of a gas generator or a free turbine, an internal temperature, the rotational speed of a rotor of the rotorcraft. This engine control unit is then configured to control a fuel metering system supplying the associated engine in order, for example, to stabilize the output shaft's rotational speed at a set point, regardless of the power consumed by that output shaft. This power varies according to the pilot's actions on flight controls, particularly on controls that collectively and/or cyclically vary the pitch of the main rotor blades on a rotorcraft. Alternatively, these flight controls can be operated by an autopilot. Regulation based on the rotational speed of the motor output shafts then ensures a permanent match between the power produced jointly by the output shafts of these motors and the power consumed by the rotor(s), so that this or these rotors rotate at a nominal rotational speed compatible with its or their function of generating lift for the rotorcraft. However, the engine control unit (ECU) is configured to prevent the power developed by an engine from exceeding a mechanical limit acceptable to the engine or the power transmission system. Typically, various operating modes, each with its own limits and durations, are then defined. For each operating mode, these limits might include, for example, a torque limit for the engine's output, an internal engine temperature limit, a rotational speed limit for an engine shaft, a torque limit for at least one component of the power transmission system, and so on. On a multi-engine aircraft, there are two operating modes known as "AEO" (All Engines Operative), which can be used for certain periods when all engines are functioning normally, and two operating modes known as "OEI" (One Engine Inoperative), which can be used for certain periods when one of the engines is out of service. The use of certain operating modes may necessitate maintenance on the engines, or even on the power transmission system. Therefore, an engine control unit (ECU) manages a fuel metering system to modulate the power of the associated engine. The fuel metering system is configured to bring the output shaft speed towards a set value, while preventing it from exceeding a limit. Furthermore, in the event of a failure or malfunction of an engine's control system, the fuel flow to the affected engine is fixed at the last used flow rate. A pilot is notified and can then either shut down the affected engine by safety, or continue the flight as is, that is to say with an unregulated engine. More generally, managing a lack of regulation of one of the engines of a rotorcraft can be complex to implement in order to pilot such a rotorcraft safely. The documents GB2079707 And US 2011/173988 They, for their part, disclose control systems for an engine, such as a gas turbine, used in the event of a failure of another engine. Such systems, however, are unrelated to the invention. The present invention aims to provide a method for limiting the workload of a crew in the event of a failure of an engine control system on a rotorcraft