Apparatus and method for controlling turbine engine high pressure shaft speed offset

Abstract

The invention relates to a method for controlling a turbine engine of an aircraft, said turbine engine comprising a high-pressure shaft and a low-pressure shaft, said method comprising the following steps: a)-detecting an acceleration request, said acceleration request increasing the fuel setpoint of the turbine engine and causing the rotational speed of said high-pressure shaft to shift relative to the rotational speed of said low-pressure shaft; b) comparing the rotational speed of the high-pressure shaft with a first predetermined threshold value (S1), and transferring torque from the high-pressure shaft if the rotational speed of the high-pressure shaft reaches the first threshold value; c) if the rotating speed of the high-pressure shaft reaches a second preset threshold value which is greater than the first threshold value, reducing the fuel oil set value; d) continuing to transfer the torque from the high-pressure shaft in order to reduce the rotational speed of the high-pressure shaft below the second threshold value.

Description

Technical Field

[0001] The present invention relates to a turbine engine for aircraft, and in particular to control of the turbine engine, so as to control the rotation speed deviation of a high-pressure shaft of the turbine engine. Existing technology

[0002] Twin-spool, twin-bypass turbine engines with a high bypass ratio (BPR) have a significant difference in inertia between the low-pressure and high-pressure spools. Therefore, during the low-pressure speed acceleration phase, increasing fuel flow in response to pilot demand, and potentially providing electrical assistance through torque injection into the low-pressure spool, can cause a significant increase in high-pressure speed, until a high-pressure speed "drift" occurs due to the inertia difference between the high-pressure and low-pressure spools. This high-pressure speed drift imposes design constraints on the high-pressure spool mechanical components from a cost and mass perspective, ensuring that the engine operates within a defined and validated operating range.

[0003] Climate change is a major concern for numerous legislators and regulators worldwide. Various countries have already adopted, are in the process of adopting, or will soon adopt various carbon emission limits. In particular, stringent standards apply to both new and in-service aircraft, necessitating the adoption of technical solutions to comply with existing regulations. The civil aviation industry has been actively contributing to the fight against climate change for many years.

[0004] Technological research and development efforts have significantly improved the environmental performance of aircraft. Applicants comprehensively consider factors affecting all stages of the design and development of aviation components and products, striving to obtain products with lower energy consumption and greater environmental impact, and integrating them into civil aviation with a minimum impact on the environment, aiming to improve the energy efficiency of aircraft.

[0005] Therefore, the Applicant is continuously working to reduce the environmental footprint of its activities by adopting relevant methods and applying benign development and manufacturing practices to minimize greenhouse gas emissions, thereby reducing the negative impact on the climate.

[0006] This ongoing R&D work applies not only to the development of new generation aircraft engines, aircraft lightweighting, electric propulsion technology, but also to the application and promotion of aviation biofuels (as a necessary complement to technological progress).

[0007] The present invention is the result of technical research aimed at significantly improving aircraft performance and thereby contributing to reducing the environmental impact of aircraft.

[0008] One of the objects of the present invention is to limit the rotational speed deviation of the high-pressure shaft and advantageously reduce the fuel consumption of the hybrid engine.

[0009] To this end, the present invention relates to a method for controlling an aircraft turbine engine comprising a high-pressure shaft and a low-pressure shaft, the method comprising the following steps:

[0010] a) detecting an acceleration request which increases the fuel setpoint of the turbine engine and causes a deviation in the rotational speed of the high-pressure shaft relative to the rotational speed of the low-pressure shaft;

[0011] b) comparing the rotational speed of the high-pressure shaft with a first predetermined threshold and transferring torque from the high-pressure shaft if the rotational speed of the high-pressure shaft reaches the first threshold;

[0012] c) if the rotational speed of the high-pressure shaft reaches a second predetermined threshold value greater than the first threshold value, reducing the fuel setting value;

[0013] d) continuing to transfer torque from the high-pressure shaft to reduce the rotational speed of the high-pressure shaft below the second threshold.

[0014] Thus, by adjusting certain setpoints and compensating for the fuel and torque setpoints, the high-pressure spool speed can be limited to below a predetermined threshold while maintaining the trajectory required to respond to acceleration requests. This helps, in particular, reduce the risk of damage to the turbine engine, particularly the high-pressure spool, due to excessive high-pressure spool speed excursions. Torque shifting advantageously reduces the high-pressure engine speed, preventing such excursions.

[0015] According to some embodiments, the method further comprises:

[0016] e) stabilizing the fuel setting and maintaining the transfer from the high pressure shaft when the rotational speed of the high pressure shaft drops below the second threshold;

[0017] f) when the speed of the low-pressure shaft reaches the speed setpoint of the low-pressure shaft, setting the torque modulation of the low-pressure shaft to zero;

[0018] g) setting the torque modulation of the high-pressure shaft to zero when the rotational speed of the high-pressure shaft drops below the first threshold.

[0019] In certain embodiments, in step b), at least a portion of the torque transferred from the high pressure shaft is injected into the low pressure shaft to limit a fuel setting.

[0020] This advantageously re-injects the power of the high-pressure shaft torque into the low-pressure shaft, thereby achieving fuel savings.

[0021] In certain embodiments, the method in step d) includes increasing the torque of the low-pressure shaft based on the torque transferred from the high-pressure shaft and injecting at least a portion of the transferred torque into the low-pressure shaft.

[0022] Thus, the mechanical power diverted from the high-pressure shaft can advantageously be at least partially reused to power the low-pressure shaft, thereby reducing the amount of fuel required to maintain the low-pressure shaft speed.

[0023] In certain embodiments, in step d), a torque increase of the low-pressure shaft is determined to compensate for the fuel setting in step c).

[0024] In some embodiments, the values ​​of the first threshold and the second threshold depend on the design size of the high-pressure shaft.

[0025] In some embodiments, the first threshold value is 5% to 6% lower than the maximum allowable value of the high-pressure shaft speed, and the second threshold value is 3% to 4% lower than the maximum allowable value of the high-pressure shaft speed.

[0026] The present invention also relates to a computer program comprising instructions for executing the method of the present invention when the computer program is executed by a computer.

[0027] The present invention also relates to a computer-readable recording medium having recorded thereon the computer program according to the present invention.

[0028] The invention also relates to a control device for an aircraft turbine engine comprising a high-pressure shaft and a low-pressure shaft, the device comprising one or more processors, which are configured jointly or individually to:

[0029] a) detecting an acceleration request which increases the fuel setpoint of the turbine engine and causes a deviation in the rotational speed of the high-pressure shaft relative to the rotational speed of the low-pressure shaft;

[0030] b) comparing the rotational speed of the high-pressure shaft with a first predetermined threshold and transferring torque from the high-pressure shaft if the rotational speed of the high-pressure shaft reaches the first threshold;

[0031] c) if the rotational speed of the high-pressure shaft reaches a second predetermined threshold value greater than the first threshold value, reducing the fuel setting value;

[0032] d) continuing to transfer torque from the high-pressure shaft so that the rotational speed of the high-pressure shaft drops below the second threshold.

[0033] The invention also relates to an aircraft comprising a device according to the invention.

[0034] Other characteristics and advantages of the invention will emerge from the following description taken in conjunction with the accompanying drawing, which shows a non-limiting embodiment.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of a turbine according to one embodiment of the present invention.

[0037] Figure 2 is a schematic diagram of a control system according to an embodiment of the present invention.

[0038] Figure 3 1 is a schematic diagram of the change curves of low-pressure speed, high-pressure speed, high-pressure shaft torque, low-pressure shaft torque and fuel according to an embodiment of the present invention.

[0039] Figure 4 is a schematic diagram of a control method according to an embodiment of the present invention.

[0040] Figure 5 It is possible to achieve Figure 2 Schematic diagram of the electronic control unit showing the control circuit.

[0041] Description of the embodiment

[0042] like Figure 1 As shown, an aircraft engine assembly 100 according to one embodiment may include a turbine engine 200, a first motor-generator 300, a second motor-generator 400, and a control unit 500. The turbine engine 200 may include a low-pressure shaft 210 and a high-pressure shaft 220. As shown, the low-pressure shaft 210 and the high-pressure shaft 220 may be coaxially arranged. The turbine engine 200 may also include a low-pressure compressor 230, a high-pressure compressor 240, a combustion chamber 250, a high-pressure turbine 260, a low-pressure turbine 270, and an exhaust nozzle 275. These are arranged sequentially along the flow direction of the annular working fluid flow, such that air drawn upstream of the low-pressure compressor 230 is compressed sequentially in the low-pressure compressor 230 and the high-pressure compressor 240, and then combusted by injecting fuel into the combustion chamber 250, generating high-temperature combustion gases in the combustion chamber 250. These combustion gases may then expand sequentially in the high-pressure turbine 260 and the low-pressure turbine 270 to drive their rotation, before being discharged through the nozzle 275. The high-pressure shaft 220 can be mechanically connected to the high-pressure turbine 260 and the high-pressure compressor 240, so that the high-pressure turbine 260 can drive the high-pressure shaft 220 and the high-pressure compressor 240 to rotate; and the low-pressure shaft 210 can be mechanically connected to the low-pressure turbine 270 and the low-pressure compressor 230, so that the low-pressure turbine 270 can drive the low-pressure shaft 210 and the low-pressure compressor 230 to rotate.

[0043] In the illustrated embodiment, the turbine engine 200 may be a twin-ducted turbojet engine and further include a fan 280. The fan 280 may also be mechanically connected to the low-pressure shaft 230 so as to be driven for rotation by the low-pressure turbine 270 via the low-pressure shaft 210. As shown, the turbine engine 200 may also include a speed reducer 290 interposed between the low-pressure shaft 210 and the fan 280, allowing the fan 280 to rotate at a lower speed than the low-pressure shaft 210. However, configurations in which the fan is directly driven by the low-pressure shaft 210 are also contemplated. Furthermore, other fanless turbine engine 200 configurations are also contemplated. Thus, the turbine engine 200 may also be a turboprop engine, wherein at least one propeller is mechanically connected to the low-pressure shaft 210 via the speed reducer 290, or a turboshaft engine, wherein at least one lift rotor is mechanically connected to the low-pressure shaft 210 via the speed reducer 290. Specifically for turboshaft or turboprop engines, it is also contemplated that the turbine engine 200 includes only a compressor mechanically connected to the high-pressure shaft 210.

[0044] As shown, the first electric motor 300 can be configured as a motor-generator to selectively convert electrical energy into mechanical work in motor mode and mechanical work into electrical energy in generator mode. The first electric motor 300 can be mechanically coupled to the low-pressure shaft 210 to drive the low-pressure shaft 210 in motor mode and be driven by the low-pressure shaft 210 in generator mode. However, within the scope of the present invention, it is also contemplated that the first electric motor 300 can be configured solely as a generator, capable of converting mechanical work into electrical energy.

[0045] Similarly, as shown, the second motor-generator 400 can also be configured as a motor-generator, selectively converting electrical energy into mechanical energy in motor mode and converting mechanical work into electrical energy in generator mode. This motor can be mechanically coupled to the high-voltage shaft 220 to drive the high-voltage shaft 220 in motor mode and be driven by the high-voltage shaft 220 in generator mode. However, it is also contemplated within the scope of the present invention that it can be configured as a pure generator, converting only mechanical work into electrical energy.

[0046] The control unit 500 may be an electronic control unit, possibly a full authority digital engine control (FADEC). It may particularly take the form of an electronic processor capable of executing computer program instructions that control the operation of the engine assembly 200. The control unit 500 receives signals representing operating parameters of the turbine engine 200. The control unit 500 may be connected to the turbine engine 200 to, in particular, control the supply of fuel to the combustion chamber 250 by providing a fuel setpoint WF_CMD thereto. The control unit 500 may also be connected to the electric motors 400 and 300 to provide a torque setpoint TRQ_CMD thereto to control the injection and / or extraction of mechanical work from the high-pressure spool 220 and the low-pressure spool 210, respectively. The control unit 500 may also be connected to manual controls (e.g., throttle lever 80) and / or the flight computer 90 to receive operating setpoints for the engine assembly 200, which may take the form of thrust, power, or speed setpoints for the low-pressure spool 210 and / or the high-pressure spool 220.

[0047] The control unit 500 can also be connected to temperature sensors 276 and 277, which are arranged downstream and upstream of the low-pressure turbine 270, respectively, to receive the combustion gas temperature leaving the low-pressure turbine 270 and the high-pressure turbine 260; connected to one or more pressure sensors (not shown), which are arranged in the combustion chamber 250 to detect the static pressure at the inlet of the combustion chamber 250 and transmit it to the control unit 500; and connected to one or more flow sensors (not shown), which are arranged in the fuel supply circuit of the combustion chamber 250.

[0048] Figure 2 is a schematic diagram of a control system according to an embodiment of the present invention.

[0049] The control system is preferably Figure 1 The control unit 500 shown is implemented in a FADEC, for example.

[0050] The system advantageously controls the speed deviation of the high-pressure shaft during the acceleration of the low-pressure shaft. In this specification, "high-pressure shaft speed deviation" refers to the high-pressure shaft speed exceeding a high threshold value related to the maximum torque of the high-pressure shaft. This deviation may be caused in particular by the inertia difference between the low-pressure shaft and the high-pressure shaft of the turbine engine. In high-bypass turbine engines, this inertia difference is particularly significant. Therefore, the acceleration of the low-pressure shaft to ensure the required acceleration time and follow a trajectory that limits the thrust asymmetry between the engines may result in a high-pressure shaft speed deviation.

[0051] The system controls at least three control parameters:

[0052] · Fuel setting value (WF32);

[0053] The power injected or transferred to or from the high-voltage shaft by the motor, or the torque setpoint of the high-voltage shaft (TRQHP);

[0054] The power injected or transferred to or from the low-pressure shaft by the motor, or the torque setpoint (TRQBP) of the low-pressure shaft.

[0055] The system can also control or limit several outputs:

[0056] · High pressure shaft speed (NH);

[0057] · Low pressure shaft speed (NL);

[0058] · Combustion chamber inlet pressure (PS3);

[0059] · Low-pressure turbine outlet temperature (T5);

[0060] · Exhaust Gas Temperature (EGT).

[0061] The control unit 500 is configured to execute a control method according to a specific embodiment of the present invention and may include multiple functions for controlling the turbine engine. It may also receive and output multiple control signals or set values ​​not mentioned within the scope of the present invention.

[0062] The control unit 500 may particularly include a module 501 configured to control the low-pressure shaft torque of the engine. The module receives the low-pressure shaft speed measurement value RegimeBP and the trajectory setting value TrajBP as input and outputs the differential torque command ΔTRQBP TrajBP and differential fuel setting ΔWF TrajBP .

[0063] The control unit 500 may further include a second module 502 that determines a second differential fuel command ΔWF seuil The module 502 receives as input a high-pressure shaft speed threshold value S2 (referred to as a second threshold value) and a high-pressure shaft speed measurement value RegimeHP.

[0064] The control unit 500 may further include a third module 503 configured to calculate the difference ΔTRQHP Pre-seuil The module 503 receives as input a high pressure shaft speed threshold value S1 (called a first threshold value) and a high pressure shaft speed measurement value RegimeHP.

[0065] The switch 504 is controlled by the signal TopAcc indicating acceleration. When the signal TopAcc is activated (ie, acceleration is detected), the signal TopAcc allows the switch 504 to select the instruction ΔTRQBP TrajBPAs the torque setpoint command for the low-pressure shaft, since this is a difference value, the difference is applied to the previous value to obtain the current low-pressure shaft torque setpoint TRQBP.

[0066] The fuel command value WF32 is obtained by selecting the incremental value ΔWF determined by the module 501. TrajBP and the incremental value ΔWF determined by module 502 seuil Since this is a difference value, the difference is applied to the previous value to obtain the current fuel command value WF32.

[0067] When the speed of the high pressure shaft of the engine is greater than the first threshold value S1, the switch 505 selects the current value ΔTRQHP pre-seui l is used as the torque command for the high-pressure shaft. Since this is a difference value, the difference is applied to the previous value to obtain the current high-pressure shaft set torque value TRQHP.

[0068] Now combine Figure 3 describe Figure 2 , Figure 3 Changes in low-pressure and high-pressure engine speeds, fuel setting WF32, and torque settings for the high-pressure shaft TRQHP and the low-pressure shaft TRQBP are shown according to one embodiment of the present invention.

[0069] When an acceleration request is detected ( Figure 3 In phase 1), as long as the high pressure shaft speed does not exceed the threshold S1, the module 501 controls the torque and fuel setting value WF32 of the low pressure shaft.

[0070] As previously mentioned, a high-bypass turbine engine may have a significant inertia difference between the low-pressure and high-pressure shafts. Therefore, during acceleration, the torque of the high-pressure shaft may rapidly reach a value that could damage it. Therefore, when the torque of the high-pressure shaft exceeds a first threshold S1, module 503 controls the torque of the high-pressure shaft by diverting torque from the high-pressure shaft. Advantageously, the torque diverted from the high-pressure shaft is at least partially reinjected into the low-pressure shaft. This advantageously reduces the amount of fuel required to follow the acceleration trajectory by replacing energy provided by fuel with mechanical energy provided by the high-pressure shaft torque.

[0071] Therefore, the deviation of the high-pressure speed is limited, but it will continue to rise slowly. Figure 3 Phase 2 is shown.

[0072] When the high pressure shaft speed reaches a second threshold value S2 higher than the first threshold value S1, the module 502 controls the fuel setting value WF32 instead of the module 501. This control includes reducing the fuel setting value to limit the deviation of the high pressure shaft speed to the threshold value S2; Figure 3 Stage 3 is shown.

[0073] When the fuel setting is lowered to limit high-pressure shaft speed deviation, the power transferred by the high-pressure shaft torque is advantageously injected into the low-pressure shaft torque to prevent it from deviating too much from the desired low-pressure shaft speed trajectory. This advantageously achieves fuel savings.

[0074] Injecting torque into the low-pressure shaft helps compensate for the reduction in fuel to maintain the trajectory as closely as possible. Figure 3 Phase 4).

[0075] When the speed of the high-pressure shaft drops below the threshold S2 again ( Figure 3 In phase 5), module 501 re-controls the fuel setting value WF32 to stabilize it and maintain the transfer from the high pressure shaft ( Figure 4 When the speed of the low-pressure shaft reaches the low-pressure shaft speed setpoint, the torque modulation of the low-pressure shaft is gradually set to zero.

[0076] When the speed of the low-pressure shaft drops below the first threshold, the torque modulation of the high-pressure shaft is gradually set to zero ( Figure 3 Phase 6). Acceleration thrust is maintained by the fuel setting.

[0077] Advantageously, the thresholds S1 and S2 depend on the design dimensions of the high-pressure shaft. For example, S1 may be between 5% and 6% below the maximum rotational speed value, and S2 may be between 3% and 4% below the maximum rotational speed value.

[0078] Figure 3 The stages or steps observed for each of the following are shown:

[0079] · High pressure shaft speed;

[0080] · Low pressure shaft speed;

[0081] High-pressure shaft torque TRQHP;

[0082] Low-pressure shaft torque TRQBP;

[0083] · Fuel setting value WF32.

[0084] The dashed curve represents the curves of the above-mentioned quantities when an embodiment of the present invention is implemented, and the solid curve represents the curve when the present invention is not implemented.

[0085] Combine Figure 2 and Figure 4 Describe the different stages or steps.

[0086] Figure 4 For example, a control unit 500 and a plurality of modules (such as Figure 2 The method of executing the above) Figure 4The method may also be executed jointly or separately by one or more processors in the control unit 500. Figure 4 The method can also be combined with Figure 3 describe, Figure 3 Changes in high-pressure and low-pressure engine speeds as well as high-pressure shaft torque TRQHP, low-pressure shaft torque TRQBP and fuel consumption WF32 are shown.

[0087] In step E1, the control unit detects whether there is an acceleration request. For example, this detection can be performed by detecting the value of the signal TopAcc. This detection can take into account hysteresis to enhance robustness against oscillations.

[0088] This acceleration request causes the speed of the high-pressure and low-pressure shafts to increase, and fuel consumption to meet the acceleration request. As previously mentioned, the inertia difference between the low-pressure and high-pressure shafts may cause the high-pressure shaft speed to offset in order to enable the low-pressure shaft to follow the trajectory. This offset can impose significant mechanical and cost constraints on the design of the high-pressure shaft to avoid damage at high speeds. Therefore, the present invention aims to limit this offset while maintaining the desired trajectory of the low-pressure shaft speed as much as possible to meet the acceleration request.

[0089] The present invention therefore makes it possible to control this deviation, in particular to achieve the following objectives:

[0090] · Normal operation of the engine (meeting aircraft bleed air requirements, richness of the air / fuel mixture in the combustion chamber, and avoiding flameout, especially when ingesting water or hail);

[0091] · Engine performance (acceleration time, deceleration time, pilot control stick);

[0092] · Physical braking limitations (fuel system sizing, motor sizing);

[0093] · Engine protection (avoiding high-pressure compressor surge, avoiding overheating and surge at low speed, avoiding loosening, overspeed limit and combustion chamber rupture, starting).

[0094] When the rotation speed of the high pressure shaft is greater than the first threshold S1, in step E2, the torque is transferred from the high pressure shaft (step E3). Transferring the torque from the high pressure shaft helps to reduce the deviation of the high pressure engine speed. Figure 3 The high-pressure speed curve in shows a slowing of the excursion (stage 2).

[0095] In certain embodiments, the torque transferred from the high pressure spool (or a portion thereof) is injected into the low pressure spool to limit the fuel setting WF32.

[0096] If the torque modulation performed on the high pressure shaft (up to the maximum possible transfer) is not sufficient to maintain the high pressure speed at the threshold S1, then in step E4 the high pressure shaft speed may reach a second threshold S2. Subsequently, the fuel setpoint WF32 is reduced (step E5), which Figure 3 This can be observed in the fuel curve of phase 3. Reducing the fuel setting WF32 and continuing to transfer torque TRQHP from the high pressure shaft advantageously limits the excursion of the high pressure shaft to below the threshold S2.

[0097] To enable the rotation speed of the low-pressure shaft to follow the trajectory, power may be injected by increasing the torque TRQBP of the low-pressure shaft (step E6 ).

[0098] In certain embodiments, the torque increase TRQBP of the low-pressure shaft is obtained by transferring the torque TRQHP from the high-pressure shaft and injecting at least a portion of the transferred torque into the low-pressure shaft.

[0099] In certain embodiments, the torque increase TRQBP of the low-pressure shaft is determined to compensate for the fuel setting WF32 in step E6 .

[0100] When the rotational speed of the high-pressure shaft falls below said second threshold value S2 (step E7 ), the fuel setting WF32 is stabilized (step E8 ) and the torque transfer to the high-pressure shaft is maintained (step E9 ).

[0101] When the low-pressure shaft speed reaches the low-pressure shaft speed setting value (step E10), the low-pressure shaft torque TRQBP is set to zero (step E11). When the high-pressure shaft speed drops below the first threshold S1 (step E12), the high-pressure shaft torque TRQHP is set to zero (step E13).

[0102] In one embodiment, Figure 2 The functional modules correspond to computer programs executed by the control unit 500. Figure 5 An example of a control unit 500 is shown. The control unit 500 has the hardware architecture of a computer and includes, in particular, one or more processors 21 (only one is shown), non-volatile memory 22, volatile memory 23, and an interface 24. The processor 21 is capable of executing a computer program stored in the non-volatile memory 22 while using the volatile memory 23. The interface 24 is capable of acquiring measurement signals and transmitting control signals.

[0103] The non-volatile memory 22 comprises in particular a computer program P1 which executes a program corresponding to one embodiment of the invention (for example in conjunction with Figure 4During the execution of the computer program P1, the interface 24 can obtain the measurement signals representing the speeds RegimeHP and RegimeBP, the TopAcc signal, and the trajectory TrajBP, and transmit the signals TRQBP, TRQHP, and WF32. Alternatively, Figure 2 At least a portion of the functional modules may correspond to a material integrated circuit, such as a programmable logic circuit.

Claims

1. A method for controlling an aircraft turbine engine, the turbine engine comprising a high-pressure shaft and a low-pressure shaft, the method comprising the following steps: a) detecting ( E1 ) an acceleration request causing an increase in the fuel setpoint of the turbine engine and resulting in a deviation of the rotational speed of the high-pressure shaft relative to the rotational speed of the low-pressure shaft; b) comparing the rotational speed of the high-pressure shaft with a first predetermined threshold value (S1) and transferring (E3) torque from the high-pressure shaft if the rotational speed of the high-pressure shaft reaches (E2) the first threshold value (S1); c) if the rotational speed of the high-pressure shaft reaches (E4) a second predetermined threshold value (S2) greater than the first threshold value (S1), reducing (E5) the fuel setting value; and d) - continuing to transfer torque from the high-pressure shaft so that (E7) the rotational speed of the high-pressure shaft drops below the second threshold (S2).

2. The method according to claim 1, wherein: e) stabilizing (E8) the fuel setting and maintaining (E9) the torque transfer from the high pressure shaft when the rotational speed of the high pressure shaft drops (E7) below the second threshold (S2); f) when the speed of the low-pressure shaft (E10) reaches the speed setpoint of said low-pressure shaft, setting the torque modulation of the low-pressure shaft to zero (E11); g) When the rotational speed of the high-pressure shaft drops ( E12 ) below the first threshold ( S1 ), setting the torque modulation of the high-pressure shaft to zero ( E13 ).

3. The method according to claim 1 or 2, wherein in step b), at least a portion of the torque transferred from the high-pressure shaft is injected into the low-pressure shaft to limit a fuel setting value.

4. The method according to any one of claims 1 to 3, comprising, in step d), increasing the torque of the low-pressure shaft based on the torque transferred from the high-pressure shaft and injecting at least a part of the transferred torque into the low-pressure shaft.

5. The method of claim 4, wherein in step d), the torque increase of the low-pressure shaft is determined to compensate for the fuel setting value in step c).

6. The method according to any one of the preceding claims, wherein the values ​​of the first and second threshold values ​​depend on the design dimensions of the high pressure shaft.

7. A computer program comprising instructions for executing the method according to any one of claims 1 to 6, when the computer program is executed by a computer.

8. A computer-readable recording medium having recorded thereon the computer program according to claim 7.

9. An apparatus for controlling an aircraft turbine engine, the turbine engine comprising a high-pressure spool and a low-pressure spool, the apparatus comprising one or more processors, the processors being configured, collectively or individually, to: a) detecting ( E1 ) an acceleration request causing an increase in the fuel setpoint of the turbine engine and resulting in a deviation of the rotational speed of the high-pressure shaft relative to the rotational speed of the low-pressure shaft; b) comparing the rotational speed of the high-pressure shaft with a first predetermined threshold (S1) and transferring (E3) torque from the high-pressure shaft if the rotational speed of the high-pressure shaft reaches (E2) the first threshold (S1); c) if the rotational speed of the high-pressure shaft reaches (E4) a second predetermined threshold value (S2) greater than the first threshold value (S1), reducing (E5) the fuel setting value; d) - continuing to transfer torque from the high-pressure shaft so that (E7) the rotational speed of the high-pressure shaft drops below the second threshold (S2).

10. An aircraft comprising the device according to claim 9.

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