Method for propulsion assistance through fault detection of an aircraft turboshaft engine

Abstract

A method for propulsion assistance by detecting a fault in a turboshaft engine of an aircraft operating in nominal mode, the aircraft including an auxiliary engine in a deactivated state. The method includes: step (2) comparing the operating parameters of the turboshaft engine with equivalent parameters of a model characterizing a healthy turboshaft engine; step (4) detecting a fault in the turboshaft engine by detecting an anomaly in at least one operating parameter of the turboshaft engine; step (6) selecting an activation mode for the auxiliary engine based on the operating parameters of the turboshaft engine and / or the flight parameters of the aircraft; and step (8) activating the auxiliary engine using the selected activation mode.

Description

Technical Field

[0001] This invention relates to providing assistance to the turboshaft engine of an aircraft after a malfunction is detected in the aircraft.

[0002] Specifically, the present invention relates to a helicopter with a dual-engine architecture, wherein one of the two engines is capable of operating in a deactivated mode or an energy-saving mode, also known as a standby mode.

[0003] In general, this invention is applicable to all aircraft that include at least two engines. Background Technology

[0004] Turboshaft engines, especially aircraft turboshaft engines such as helicopter turboshaft engines, must be started before they can provide thrust or mechanical power to the rotor. Specifically, starting up involves heating the turboshaft engine components and rotating the turbine.

[0005] During the flight phase of an aircraft with a twin-turboshaft engine architecture, one turboshaft engine may be shut down due to the adoption of a specific flight mode (e.g., an energy-saving mode also known as standby mode), while the other turboshaft engine operates in its nominal mode.

[0006] In this standby mode, further described in detail in document FR2967132A1, the turboshaft engine maintains low-speed rotation driven by combustion gases or an auxiliary device such as an electric motor. In this standby mode, the combustion chamber can be shut off. In one variant, the combustion chamber is ignited, and the rotation of the turboshaft engine may or may not be assisted.

[0007] To exit this standby mode, especially in the event of a failure in a turboshaft engine operating in nominal mode, the turboshaft engine can be restarted via a normal restart or a quick restart. Document FR3027058A1 specifically mentions that a normal restart takes 10 seconds to 1 minute, while a quick restart takes 5 to 15 seconds.

[0008] To detect faults or failures in turboshaft engines employing a twin-turboshaft engine architecture, the performance and parameters of the two turboshaft engines are typically compared when both are running in the same manner and at the same speed.

[0009] However, when one of the two turboshaft engines is in standby mode, it is impossible to detect the fault by comparing the two turboshaft engines and comparing the consistency of their performance and operating parameters, because the turboshaft engine in standby mode has a lower speed and temperature than the turboshaft engine in nominal mode. Summary of the Invention

[0010] Therefore, the present invention aims to overcome the above-mentioned disadvantages and improve the detection of turboshaft engine faults, while better managing the activation of auxiliary engines when faults are detected.

[0011] The purpose of this invention is to provide a method for propulsion assistance by detecting a fault in the turboshaft engine of an aircraft operating in nominal mode, the aircraft including an auxiliary engine in a deactivated state. Nominal mode refers to the normal operating mode in which the engine provides power. The method includes: comparing the operating parameters of the turboshaft engine with equivalent parameters of a model characterizing a healthy turboshaft engine; detecting a fault in the turboshaft engine by detecting an anomaly in at least one operating parameter of the turboshaft engine; selecting an activation mode for the auxiliary engine based on the operating parameters of the turboshaft engine and / or the flight parameters of the aircraft; and activating the auxiliary engine using the selected activation mode; wherein the operating parameters or detectable faults of the turboshaft engine include at least one of the following parameters: deterioration of turboshaft engine performance control quality; incompatibility between the nominal operating mode of the turboshaft engine and a reduction margin relative to the following parameters: turboshaft engine speed, turboshaft engine internal temperature, torque provided by the turboshaft engine, turboshaft engine acceleration or deceleration, or fuel flow limit; abnormal vibration level of the turboshaft engine; abnormally high temperature of the aircraft computer; connection failure between the electronic control system of the turboshaft engine and the central computer of the aircraft; detection of a fire in the turboshaft engine; and detection of power oscillation of the turboshaft engine.

[0012] Therefore, instead of detecting turboshaft engine faults by comparing them to another active turboshaft engine, the faults are detected by comparing them to an internal model characterizing a healthy turboshaft engine. In this invention, when the operating parameters of the turboshaft engine become abnormal, the operating parameters of the turboshaft engine have the same meaning as detectable faults.

[0013] The model characterizing a healthy turboshaft engine is a virtual engine that operates with the same parameters as the turboshaft engine but without failure, thereby improving the detection and quantification of faults in the turboshaft engine.

[0014] In one embodiment, the flight parameters of the aircraft include the aircraft's flight altitude, and the activation mode of the auxiliary engine is selected based on the probability of maintaining the aircraft's flight altitude for the duration required to activate the auxiliary engine.

[0015] Advantageously, the step of comparing the operating parameters of the turboshaft engine with the equivalent parameters of a model characterizing a healthy turboshaft engine is performed by a turboshaft engine computer that stores the model characterizing a healthy turboshaft engine.

[0016] In one embodiment, the step of detecting a fault in the turboshaft engine includes measuring a significant difference between the operating parameters of the turboshaft engine and equivalent parameters of a model characterizing a healthy turboshaft engine.

[0017] Advantageously, the activation mode of the auxiliary engine is selected from a normal activation mode having a first activation duration, an accelerated activation mode having a second activation duration, and a fast activation mode having a third activation duration, wherein the first duration is longer than the second duration, and the second duration is longer than the third duration; the normal activation mode is preferred over the accelerated activation mode; and the accelerated activation mode is preferred over the fast activation mode.

[0018] In one particular embodiment, the auxiliary engine is a second turboshaft engine.

[0019] Advantageously, the normal activation mode includes the step of thermally stabilizing the auxiliary engine at a predetermined temperature, and the normal activation mode is preferentially used when no fault of the turboshaft engine is detected and the aircraft's onboard computer and / or pilot issues a corresponding command to the auxiliary engine.

[0020] Advantageously, the operating parameters or detectable faults of the turboshaft engine include: fuel flow rate, and / or temperature and / or speed at the high-pressure turbine outlet of the turboshaft engine, and / or outlet pressure and / or torque of the compressor of the turboshaft engine, and / or combustion chamber shutdown of the turboshaft engine, and / or lubricating oil circuit leakage, and / or fuel circuit leakage, and / or detection of metal debris, and / or inability to adjust the performance of the turboshaft engine, and / or inconsistency between power demand and provided power, and / or potential impact on the flight trajectory of the aircraft.

[0021] In one embodiment, the auxiliary engine is a second turboshaft engine, and the normal activation mode, the accelerated activation mode, and the rapid activation mode all include assisting the second turboshaft engine via the aircraft's motors; the normal activation mode includes thermally stabilizing the second turboshaft engine at a predetermined temperature and employing a fuel supply rule that makes the activation time 1 minute to 3 minutes; the accelerated activation mode includes employing a fuel supply rule that makes the activation time 10 seconds to 1 minute; and the rapid activation mode includes using a specific start-up system (the specific start-up system is configured to provide auxiliary torque) and employing a fuel supply rule that makes the activation time of the second turboshaft engine 5 seconds to 15 seconds.

[0022] In one particular embodiment, the auxiliary engine in the deactivated state corresponds to the following operating modes of the auxiliary engine: an operating mode equivalent to the standby mode, or an operating mode between the standby mode and the nominal operating mode. Attached Figure Description

[0023] Other objects, features, and advantages of the invention will become apparent from the following description, which is provided by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0024] [ Figure 1 The steps of the method according to the present invention are shown;

[0025] [ Figure 2 [Illustration] is a schematic diagram showing the different states of an auxiliary engine according to an activation mode selected for the auxiliary engine during the implementation of the method according to the invention. Detailed Implementation

[0026] In one embodiment, the method according to the invention is implemented in an aircraft (e.g., a helicopter) that includes a turboshaft engine and an auxiliary engine capable of providing power to the aircraft's main gearbox.

[0027] The auxiliary engine is, for example, an electric motor or a second turboshaft engine. The following description will use a second turboshaft engine as an example, where the aforementioned turboshaft engine is considered as the first turboshaft engine.

[0028] The first turboshaft engine and the second turboshaft engine each include, for example: a compressor that increases the gas pressure at the inlet of the turboshaft engine; a combustion chamber that increases the temperature of the compressed gas; and an expansion turbine that also drives the compressor.

[0029] Specifically, the first turboshaft engine and the second turboshaft engine are, for example, free-turbine turboshaft engines, and the expansion turbine is divided into a high-pressure turbine and a power turbine. The high-pressure turbine is also called a gas generator turbine, and the power turbine is also called a free turbine.

[0030] The method according to the invention is implemented particularly when the aircraft is operating in a specific fuel consumption mode, such as an energy-saving mode. Specifically, one of the two turboshaft engines (e.g., the first turboshaft engine) operates in nominal mode (in other words, an operating mode that provides standard performance and enables the aircraft to fly in the atmosphere), while the second turboshaft engine operates in a deactivated mode. Specifically, the deactivated mode refers to the standby mode of the second turboshaft engine, or a consumption mode between the standby mode and the nominal mode of the second turboshaft engine.

[0031] The intermediate consumption mode is, for example, the operating mode in which the second turboshaft engine switches from its nominal mode to standby mode or from its standby mode to its nominal mode.

[0032] The standby mode is a consumption mode that allows the second turboshaft engine of the aircraft to have lower fuel consumption, while allowing for rapid activation in the event that the aircraft requires both turboshaft engines or the first turboshaft engine fails.

[0033] Figure 1 The steps of a propulsion assistance method are illustrated schematically by detecting faults in the aircraft's turbine shaft engine.

[0034] When implementing this method, step 2 is performed first, in which the operating parameters of the first turboshaft engine are compared with the model equivalent parameters characterizing a healthy turboshaft engine.

[0035] A model characterizing a healthy turboshaft engine is stored, for example, in a computer of the first turboshaft engine, which performs step 2 of comparing operating parameters.

[0036] Then, step 4 is performed, in which an anomaly is detected in at least one operating parameter of the first turbine shaft engine.

[0037] Step 4, which detects anomalies, includes, for example, measuring significant differences between the operating parameters of the first turboshaft engine and the equivalent parameters of a model characterizing a healthy turboshaft engine. A significant difference is defined as a difference whose value for each operating parameter is predetermined and indicates a failure in the first turboshaft engine.

[0038] The operating parameters or detectable faults of the turboshaft engine include at least one of the following parameters: deterioration of turboshaft engine performance control quality; incompatibility between the nominal operating mode of the turboshaft engine (or more broadly, the energy-saving mode of the aircraft) and a reduction margin relative to the following operating limits: turboshaft engine speed, turboshaft engine internal temperature, turboshaft engine torque provided, turboshaft engine acceleration or deceleration, or fuel flow limit; abnormal vibration level of the turboshaft engine; abnormally high temperature of the aircraft computer; connection failure between the electronic control system of the turboshaft engine (also known as FADEC in the prior art) and the central computer of the aircraft and / or the central computer of the second turboshaft engine; detection of a fire in the turboshaft engine; and detection of power oscillation of the turboshaft engine.

[0039] Furthermore, the operating parameters of the first turboshaft engine, and more broadly, detectable faults, include anomalies related to: fuel flow rate; and / or temperature at the high-pressure turbine outlet; and / or rotational speed at the high-pressure turbine outlet of the turboshaft engine; and / or compressor outlet pressure of the turboshaft engine; and / or torque; and / or combustion chamber shutdown of the turboshaft engine; and / or lubricating oil circuit leakage; and / or fuel circuit leakage; and / or pressure difference between a predetermined pressure and the current pressure in the lubricating oil circuit or fuel circuit; and / or detection of debris; and / or overspeed protection being triggered; and / or inability to adjust the performance of the turboshaft engine; and / or inconsistency between power demand and supplied power; and / or potential impact on the flight trajectory of the aircraft, which can be detected, for example, by: abnormal rotational speed of the free turbine of the turboshaft engine, indicating overspeed or underspeed; changes in atmospheric pressure, indicating that the aircraft is moving away from or near the ground; changes in power demand; changes in the power consumed by the engine; or reaching a minimum power threshold or a maximum power threshold.

[0040] Then, step 6 is performed, in which the activation mode of the second turboshaft engine is selected based on the previously detected fault, and more generally based on the operating parameters of the first turboshaft engine and / or the flight parameters of the aircraft and / or the potential impact on the flight trajectory of the aircraft.

[0041] Finally, after selecting the activation mode, step 8 is performed, in which the second turbine shaft engine is activated according to the selected activation mode.

[0042] Figure 2 A schematic diagram illustrates the different states of the second turboshaft engine depending on the activation mode selected for the second turboshaft engine.

[0043] Specifically, Figure 2 The diagram illustrates a nominal consumption mode 10, a standby mode 12, and an intermediate consumption mode 14 between the standby mode 12 and the nominal mode 10 for the second turboshaft engine. Step 8, activating the second turboshaft engine according to the selected activation mode, is particularly applicable when the second turboshaft engine is in an operating mode such as the standby mode 12 or the intermediate consumption mode 14. In these modes, the combustion chamber may be shut off, while the gas generator turbine rotates at a low speed, for example, by means of an electric motor. Alternatively, the combustion chamber is ignited, and the rotation of the gas generator turbine may or may not be driven assisted.

[0044] During step 8, three different activation modes can be implemented, and these activation modes can be automatically selected by the computer of the second turboshaft engine or manually selected by the pilot of the aircraft.

[0045] Specifically, the three activation modes may have different effects on the aging of the second turbine shaft engine.

[0046] In one of the three possible modes, when the aircraft and / or the first turboshaft engine and / or the pilot meets the first condition C1, the step of adopting normal activation mode 16 can be performed. Normal activation mode 16 has a first duration for entering the nominal mode of the second turboshaft engine. This activation mode is the longest possible activation mode and is particularly effective in protecting the mechanical integrity / consistency of the second turboshaft engine.

[0047] In one embodiment, the first condition C1 includes: the second turboshaft engine receiving an activation command from the onboard computer and / or the aircraft pilot, and / or the second turboshaft engine's FADEC issuing an activation command based on internal conditions.

[0048] The normal activation mode 16 includes the step of thermally stabilizing the second turboshaft engine at a predetermined temperature. In a variant, mode 16 includes the step of gradually increasing the power of the second turboshaft engine until the power provided by the first turboshaft engine and the second turboshaft engine reaches equilibrium.

[0049] Normal activation mode 16 also includes adopting fuel supply rules and optimizing torque, thereby reducing the activation time to 1 to 3 minutes.

[0050] Therefore, mode 16 enables the temperature of the components of the second turbine shaft engine to change gradually.

[0051] Normal activation mode 16 is the most commonly used activation mode when activation is not urgent. This mode has the least impact on the aging of the turboshaft engine, so it is the preferred mode.

[0052] The second possible activation type is to use accelerated activation mode 18. When the aircraft and / or the first turboshaft engine meets the second condition C2, accelerated activation mode 18 has a second duration for which the second turboshaft engine enters the nominal mode of the second turboshaft engine.

[0053] The second condition C2 includes, for example, detecting a failure of the first turboshaft engine and / or the second turboshaft engine and / or other parts of the aircraft; more broadly, detecting an anomaly characterizing the failure, such as loss of sensor redundancy, excessively high lubricating oil temperature, or loss of the aircraft's energy supply.

[0054] In one variant, the second condition C2 includes: detecting flight conditions that require the second turboshaft engine to operate in nominal mode 10. For example, the measured atmospheric pressure is incompatible with operating in nominal mode using only one turboshaft engine, thus requiring activation of the second turboshaft engine. Alternatively, the second condition C2 includes: the second turboshaft engine receiving an activation command from the onboard computer and / or the aircraft pilot.

[0055] Accelerated activation mode 18 is essentially similar to normal activation mode 16, but includes implementing a fuel supply rule that makes the activation time 10 seconds to 1 minute. Therefore, accelerated activation mode 18 takes less time (especially since it does not include a thermal stabilization step) and can quickly activate the second turboshaft engine. However, this activation mode has a significant impact on the aging of the second turboshaft engine.

[0056] The third activation mode is a rapid activation mode 20; when the aircraft and / or the first turboshaft engine meets the third condition C3, the rapid activation mode 20 has a third duration for which the second turboshaft engine enters its nominal mode 10.

[0057] The third condition C3 also includes: detecting, for example, a failure of the first turboshaft engine; or more broadly, detecting anomalies characterizing a failure (which results in power loss), such as abnormal fuel flow rates, and / or abnormal temperature and / or rotational speed at the high-pressure turbine outlet of the first turboshaft engine, and / or abnormal compressor outlet pressure of the turboshaft engine, and / or abnormal torque, and / or detection of combustion chamber shutdown of the turboshaft engine, and / or leakage in the lubricating oil circuit, and / or leakage in the fuel circuit, and / or detection of debris, and / or inability to regulate the performance of the turboshaft engine, and / or inconsistency between power demand and supplied power, and / or potential impact on the flight trajectory of the aircraft. Because these anomalies may indicate a significant power loss in the first turboshaft engine, rapid activation of the second turboshaft engine is typically required.

[0058] Alternatively, the third condition C3 includes: detecting flight conditions that urgently require the second turboshaft engine to operate in nominal mode 10; or the second turboshaft engine receiving an activation command from the aircraft's onboard computer and / or the pilot.

[0059] Quick Activation Mode 20 differs from the previous two activation modes. Specifically, Quick Activation Mode 20 includes the use of a specific startup system configured and designed to implement fuel supply rules that result in an activation time of 5 to 15 seconds (approximately 10 seconds).

[0060] However, the quick activation mode 20 has a significant impact on the aging of the second turbine shaft engine, so it should only be used in emergency situations.

[0061] Of the three activation modes, normal activation mode 16 is preferred over accelerated activation mode 18, and accelerated activation mode 18 is preferred over fast activation mode 20. This is because the activation mode with less impact on aging is preferred, even though the first duration is longer than the second duration, and the second duration is longer than the third duration.

[0062] Optionally, the second turboshaft engine includes an auxiliary motor, and each of the normal activation mode, acceleration activation mode, and rapid activation mode includes a step in which the second turboshaft engine is assisted by the aircraft's auxiliary motor.

[0063] In other words, when the second turbine shaft engine is activated, the auxiliary motor participates in the rotation of the second turbine shaft engine to accelerate the activation.

[0064] In one particular embodiment, the standby mode of the second turboshaft engine involves keeping the combustion chamber ignited; this standby mode is also known as a super idle mode, while the quick-activation mode requires electric motor assistance for the second turboshaft engine.

[0065] Advantageously, the aircraft's flight parameters include the aircraft's altitude, and the activation mode of the auxiliary engine (in other words, the second turboshaft engine) is selected based on the probability of maintaining the aircraft's altitude for the time required to activate the second turboshaft engine.

[0066] Therefore, each of the first, second, and third conditions includes the additional condition of maintaining the aircraft's altitude for the time required to activate the second turboshaft engine. This is because, although the normal activation mode 16 is preferred due to its smaller impact on the aging of the second turboshaft engine, a faster activation mode will be preferred if this mode cannot guarantee maintaining the aircraft's altitude. The same reasoning applies to the accelerated activation mode 18.

[0067] In addition, when the conditions for another activation mode are met, the current activation mode can be interrupted and the other activation mode can be used preferentially.

[0068] For example, when normal activation mode 16 is being implemented but a significant fault is detected, fast activation mode 20 is implemented. However, if a particular boot system has a fault 22, accelerated activation mode 18 is ultimately implemented.

[0069] In one embodiment, the computer of the second turboshaft engine continuously implements the method as long as the second turboshaft engine is not in its nominal operating mode 10. Therefore, the parameter comparison step 2 and the fault detection step 4 only stop when the second turboshaft engine is in its nominal operating mode 10.

Claims

1. A method for providing propulsion assistance by detecting a fault in a turboshaft engine of an aircraft operating in nominal mode, said aircraft including an auxiliary engine in a deactivated state, characterized in that, The method includes: Step (2) compare the operating parameters of the turboshaft engine with the equivalent parameters of the model characterizing a healthy turboshaft engine; Step (4): Detect the fault of the turboshaft engine by detecting an abnormality in at least one operating parameter of the turboshaft engine; Step (6): Select the activation mode of the auxiliary engine based on the operating parameters of the turboshaft engine and / or the flight parameters of the aircraft; and Step (8): Activate the auxiliary engine using the selected activation mode. The operating parameters or detectable faults of the turboshaft engine include at least one of the following parameters: Deterioration in the performance tuning quality of turboshaft engines; The incompatibility between the nominal operating mode of the turboshaft engine and the reduction margin relative to the following parameters: the speed of the turboshaft engine, the internal temperature of the turboshaft engine, the torque provided by the turboshaft engine, the acceleration or deceleration of the turboshaft engine, or the fuel flow limit. The abnormal vibration level of the turboshaft engine; The aircraft's computer overheated. The electronic control system of the turboshaft engine failed to connect to the central computer of the aircraft. A fire was detected in the turboshaft engine; and Power oscillations were detected in the turbine shaft engine.

2. The method according to claim 1, wherein, The flight parameters of the aircraft include the aircraft's flight altitude, and the activation mode of the auxiliary engine is selected based on the probability of maintaining the aircraft's flight altitude for the duration required to activate the auxiliary engine.

3. The method according to any one of claims 1 and 2, wherein, Step (2), which compares the operating parameters of the turboshaft engine with the equivalent parameters of a model characterizing a healthy turboshaft engine, is performed by a computer of the turboshaft engine, wherein the computer stores the model characterizing a healthy turboshaft engine.

4. The method according to any one of claims 1 to 3, wherein, The step (4) of detecting the fault of the turboshaft engine includes: measuring the significant difference between the operating parameters of the turboshaft engine and the equivalent parameters of the model characterizing a healthy turboshaft engine.

5. The method according to any one of claims 1 to 4, wherein, The activation mode of the auxiliary engine is selected from a normal activation mode (16) with a first activation duration, an accelerated activation mode (18) with a second activation duration, and a rapid activation mode (20) with a third activation duration, wherein the first duration is longer than the second duration, and the second duration is longer than the third duration. Compared to the accelerated activation mode (18), the normal activation mode (16) is preferred, and compared to the fast activation mode (20), the accelerated activation mode (18) is also preferred.

6. The method according to any one of claims 1 to 5, wherein, The auxiliary engine is a second turboshaft engine.

7. The method according to claims 5 and 6, wherein, The normal activation mode (16) includes the step of thermally stabilizing the auxiliary engine at a predetermined temperature, and the normal activation mode (16) is preferentially used when no fault of the turboshaft engine is detected and the aircraft’s onboard computer and / or pilot issues a corresponding instruction to the auxiliary engine.

8. The method according to any one of claims 1 to 7, wherein, The operating parameters of the turboshaft engine or the detectable fault also include: Fuel flow, and / or The temperature and / or speed at the high-pressure turbine outlet of the turboshaft engine, and / or The compressor outlet pressure of the turboshaft engine, and / or Torque, and / or The combustion chamber of the turboshaft engine is shut down, and / or Lubricating oil circuit leakage, and / or Fuel circuit leak, and / or Metal fragments were detected, and / or Unable to adjust the performance of the turboshaft engine, and / or There is a mismatch between power demand and the power supplied, and / or The potential impact on the flight trajectory of the aircraft.

9. The method according to any one of claims 5 to 8, wherein, The auxiliary engine is a second turboshaft engine, and the normal activation mode (16), the acceleration activation mode (18) and the rapid activation mode (20) all include the second turboshaft engine being assisted by the aircraft's motors; The normal activation mode (16) includes thermally stabilizing the second turbine shaft engine at a predetermined temperature and adopting a fuel supply rule that makes the activation time 1 minute to 3 minutes. The accelerated activation mode (18) includes employing a fuel supply rule that makes the activation time 10 seconds to 1 minute; and The rapid activation mode (20) includes using a specific start-up system configured to utilize auxiliary torque and employing a fuel supply rule that makes the activation time of the second turbine shaft engine between 5 and 15 seconds.

10. The method according to any one of claims 1 to 9, wherein, The auxiliary engine in the deactivated state corresponds to the following operating modes: an operating mode equivalent to the standby mode, or an operating mode between the standby mode and the nominal operating mode.

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