METHOD FOR STOPPING AN AIRCRAFT TURBOMACHINE IN THE EVENT OF A FIRE IN THE TURBOMACHINE COMPARTMENT
A method using redundant temperature sensors in a non-fireproof computer safely shuts down the turbomachine during a fire, addressing the risk of non-fireproof computers in the engine compartment by ensuring timely shutdown before critical temperatures are reached.
Patent Information
- Application Number
- FR2023005057
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-05-23
- Publication Date
- 2025-10-10
- Estimated Expiration
- 2043-05-23
AI Technical Summary
Existing aircraft turbomachines controlled by non-fireproof computers in the engine compartment lack a reliable method to safely shut down during a fire, posing a risk due to their exposure to high temperatures without additional fire-resistant elements.
A method involving a non-fireproof computer with redundant temperature sensors compares temperature thresholds to quickly stop the turbomachine before reaching critical temperatures, using its own and redundant sensors to ensure safety.
The method enables rapid and safe shutdown of the turbomachine during a fire, protecting the aircraft from potential dangers by preventing further deterioration of the computer and ensuring passenger safety.
Smart Images
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Abstract
Description
Title of the invention: METHOD FOR STOPPING AN AIRCRAFT TURBOMACHINE IN THE EVENT OF A FIRE IN THE TURBOMACHINE COMPARTMENT Technical field of the invention
[0001] The present invention relates to a method for stopping an aircraft turbomachine in the event of a fire in the turbomachine compartment, the method being carried out by a non-fireproof computer controlling the turbomachine and placed in the turbomachine compartment. The invention also relates to an aircraft and to a propulsion system comprising an engine compartment in which a turbomachine and a non-fireproof computer controlling the turbomachine are placed, the computer being configured to carry out such a method. Technical background
[0002] Conventionally, an aircraft turbomachine is controlled by a computer better known by the English acronym FADEC for “Full Authority Digital Engine Control”.
[0003] Generally, such a computer is “fireproof” when it is placed in the engine compartment which is considered by engine manufacturers to be a “fire zone”, and in other words an area where the risk of fire is high due in particular to the presence of flammable liquids and ignition sources. Conversely, generally, the computer is “non-fireproof” when it is placed in an area which is considered by engine manufacturers to be a “fire-free zone”, for example the passenger compartment of the aircraft.
[0004] The term "fireproof" which is associated with the computer means that the computer is coupled to one or more additional fire-resistant elements (or fire breakers) generally arranged around the computer, to protect it against the extreme conditions of a fire. Conversely, the term "non-fireproof" which is associated with the computer means that the computer does not include this or these additional fire-resistant elements (or fire breakers).
[0005] In the event of a fire in the engine compartment, it is required that the computer (fireproof or not) be stable and capable of carrying out a pre-established safety procedure, and in other words it is imperative to avoid undesired operation of the turbomachine (for example overspeed, overtorque, reverse thrust, etc.) which could endanger the passengers of the aircraft.
[0006] Compared to a fireproof computer, a non-fireproof computer has the advantage of being lighter, less bulky and simpler to maintain.
[0007] However, a non-fireproof computer requires, due to its positioning in a “fire-safe zone”, a more complex installation (in particular an installation with longer cables and passages in different partitions) due to the distance between the computer and the associated turbomachine.
[0008] Engine manufacturers thus note an interest in developing a safety procedure carried out by a non-fireproof computer placed in the engine compartment, to benefit both from the advantages of the non-fireproof computer (compared to the fireproof computer), but also from the advantages linked to the positioning of the computer directly in the engine compartment.
[0009] The objective of the present invention is therefore to provide a simple, effective and economical solution making it possible to respond to the aforementioned problem. Summary of the invention
[0010] The invention thus proposes a method for stopping an aircraft turbomachine in operation in the event of a fire in a compartment in which the turbomachine is placed, the method being carried out by a non-fireproof computer controlling the turbomachine and placed in the compartment, the method chronologically comprising the steps consisting of: a) comparing the temperature of the computer or a parameter associated with the temperature of the computer with a predetermined threshold on a first channel of the computer, the temperature of the computer or the associated parameter being determined from a first temperature sensor which is specific to the computer; c) stopping the turbomachine, if the comparison carried out in step a) indicates that the temperature of the computer or the associated parameter is higher than the predetermined threshold.
[0011] Such a stopping method allows the computer to quickly and simply stop the turbomachine with which it is associated in the event of a fire in the engine compartment, by exploiting the measurements provided by its own temperature sensor (first temperature sensor), and all this well before reaching its maximum admissible temperature.
[0012] As soon as the turbomachine is stopped, the computer can deteriorate without representing a danger for the passengers of the aircraft.
[0013] Such a shutdown method can thus be carried out by a non-fireproof computer placed directly in the engine compartment, in order to benefit both from the advantages of the non-fireproof computer (compared to the fireproof computer), but also from the advantages linked to the positioning of the computer directly in the engine compartment.
[0014] The method according to the invention may comprise one or more of the following characteristics and / or steps, taken in isolation from one another or in combination with one another: - step a) is subdivided into two sub-steps consisting of: al) comparing the temperature of the calculator with a first predetermined threshold on the first channel of the calculator; a2) comparing the parameter associated with the temperature of the calculator with a second predetermined threshold on the first channel of the calculator; the turbomachine being stopped in step c), if the comparison carried out in sub-step al) indicates that the temperature of the calculator is greater than the first threshold, and if the comparison carried out in sub-step a2) indicates that the associated parameter is greater than the second threshold; - the parameter is the gradient of the temperature of the calculator as a function of time; - the method comprises before step c) a step consisting of: b) comparing the temperature of the computer on the first channel of the computer with the temperature of the computer on a second channel of the computer which is redundant to the first channel, the temperature of the computer on the second channel being determined from a second temperature sensor which is specific to the computer; the turbomachine being stopped in step c), if the comparison carried out in step b) indicates that the temperature of the computer on the first channel is equal to the temperature of the computer on the second channel taking into account a predetermined tolerance, for example a tolerance of five degrees Celsius; - the method generates an alert Al signaling an inconsistency between the temperature of the computer on the first channel and the temperature of the computer on the second channel, if the comparison carried out in step b) reveals a disparity greater than the predetermined tolerance between the temperature of the computer on the first channel and the temperature of the computer on the second channel; - sub-step a1) is carried out before step b) and sub-step a2) is carried out after step b); - the process generates an alert A2 signaling an abnormally high temperature of the calculator, if the comparison carried out in sub-step a2) indicates that the associated parameter is lower than the second threshold; - step c) also consists of putting the variable-pitch fan blades or the variable-pitch propeller blades in the flag position, when the turbomachine comprises a fan fitted with variable-pitch blades or a propeller fitted with variable-pitch blades.
[0015] The present invention also relates to an aircraft, such as a helicopter, comprising a compartment in which a turbomachine and a non-fireproof computer controlling the turbomachine, the computer being configured to carry out the method of stopping the turbomachine as described previously.
[0016] The present invention finally relates to an aircraft propulsion system, such as a turboprop, comprising a compartment in which a turbomachine and a non-fireproof computer controlling the turbomachine are placed, the computer being configured to carry out the method of stopping the turbomachine as described previously. Brief description of the figures
[0017] The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:
[0018] [Fig-1] [Fig.l] is a schematic view of an aircraft according to the invention;
[0019] [Fig.2] [Fig.2] is a schematic view of a propulsion system according to the invention;
[0020] [Fig.3] [Fig.3] is a diagram of a method for stopping a turbomachine, according to a first embodiment;
[0021] [Fig.4] [Fig.4] is a diagram of a process for stopping a turbomachine, according to a second embodiment. Detailed description of the invention
[0022] In [Fig.l] is schematically represented an aircraft 1 comprising a compartment 2 (more commonly called “engine compartment”) in which are placed a turbomachine 3 and a non-fireproof computer 4 controlling the turbomachine 3. The computer 4 is configured to carry out the different methods of stopping the turbomachine 3, as described in the remainder of the description.
[0023] More precisely, the aircraft 1 is here a helicopter and the turbomachine 3 is here a turboshaft engine 3. The turboshaft engine 3 drives in particular a main rotor 5 of the helicopter via a main gearbox (known by the acronym BTP) and a rear tail rotor 6 of the helicopter via a rear gearbox (known by the acronym BTA).
[0024] The embodiment illustrated in [Fig.l] is in no way limiting. The aircraft 1 could be, for example, an airplane or, more generally, a conventional horizontal take-off and landing aircraft involving the use of a runway (better known by the English acronym CTOL for “conventional take-off and landing”), a drone, a vertical take-off and landing aircraft (better known by the English acronym VTOL for “Vertical Take-off and Landing”) or a short take-off and landing aircraft (better known by the English acronym STOL for “Short Take-off and Landing”). The turbomachine 3 could be, for example, a turbojet, a turboprop or a turbogenerator.
[0025] [Fig. 2] schematically shows an aircraft propulsion system 7 comprising a compartment 8 in which a turbomachine 9 and a non-fireproof computer 10 controlling the turbomachine 9 are placed. The computer 10 is configured to carry out the various methods of stopping the turbomachine 9, as described in the remainder of the description.
[0026] More precisely, the propulsion system 7 comprises a nacelle 11 forming the compartment 8 in which the turbomachine 9 is placed, which is here a turboprop 9. The turboprop 9 comprises a propulsive propeller 12 which is driven by a power turbine coupled to a gas generator. The propeller 12 comprises an annular row of variable-pitch blades 13.
[0027] The embodiment illustrated in [Fig.2] is in no way limiting, the turbomachine 9 could be for example a turbojet, a turboshaft engine or a turbomachine equipped with one or more unducted fans.
[0028] Conventionally, the computer 4, 10 controls the turbomachine 3, 9 by controlling the different actuators of the turbomachine 3, 9, in particular from measurements provided by different sensors and from a program pre-recorded in the computer 4, 10.
[0029] Advantageously, the computer 4, 10 is of the FADEC type for “Full Authority Digital Engine Control”.
[0030] Advantageously, and as illustrated in Figures 1 and 2, the computer 4, 10 has two redundant channels, and thus comprises a first channel and a second channel which is redundant to the first channel. The channels operate in parallel, and in other words independently of one another, to ensure redundancy in the event of failure of one or other of the channels.
[0031] The first channel is associated with a first temperature sensor 14 of the computer 4, 10 and the second channel is associated with a second temperature sensor 15 of the computer 4, 10. The first and second temperature sensors 14, 15 of the computer 4, 10 are distinct from one another and specific to the computer 4, 10. Each temperature sensor 14, 15 provides its own measurements to the channel with which it is associated.
[0032] Each of the channels of the computer 4, 10 can have an active state (control) or a passive state (waiting or monitoring). The channel having an active state delivers orders to the different actuators of the turbomachine 3, 9, while the channel having a passive state is silent with respect to these same actuators.
[0033] The temperature sensors 14, 15 are for example thermocouples.
[0034] According to the invention, the computer 4, 10 is configured to carry out a method of stopping the turbomachine 3, 9, in the event of a fire in the compartment 2, 8 in which the turbomachine 3, 9 and the computer 4, 10 are placed.
[0035] More specifically, the stopping method chronologically comprises the steps of: a) comparing the temperature of the computer 4, 10 or a parameter associated with the temperature of the computer 4, 10 with a predetermined threshold (or reference value) on a first channel of the computer 4, 10, the temperature of the computer 4, 10 or the associated parameter being determined from the first temperature sensor 14 which is specific to the computer 4, 10; c) stop the turbomachine 3, 9, if the comparison carried out in step a) indicates that the temperature of the computer 4, 10 or the associated parameter is higher than the predetermined threshold.
[0036] Such a shutdown method allows the computer to quickly and simply shut down the turbomachine with which it is associated in the event of a fire in the engine compartment, by exploiting the measurements provided by its own temperature sensor (first temperature sensor), and all this well before reaching its maximum admissible temperature.
[0037] As soon as the turbomachine is stopped, the computer can deteriorate without representing a danger for the passengers of the aircraft.
[0038] Such a shutdown method can thus be carried out by a non-fireproof computer placed directly in the engine compartment, in order to benefit both from the advantages of the non-fireproof computer (compared to the fireproof computer), but also from the advantages linked to the positioning of the computer directly in the engine compartment.
[0039] The parameter associated with the temperature of the computer 4, 10 may be the gradient of the temperature of the computer 4, 10 as a function of time.
[0040] Step a) can be subdivided into two sub-steps consisting of: al) comparing the temperature of the computer 4, 10 with a first predetermined threshold on the first channel of the computer 4, 10; a2) comparing the parameter associated with the temperature of the computer 4, 10 with a second predetermined threshold on the first channel of the computer 4, 10; the turbomachine 3, 9 being stopped in step c), if the comparison carried out in sub-step a1) indicates that the temperature of the computer 4, 10 is greater than the first threshold, and if the comparison carried out in sub-step a2) indicates that the associated parameter is greater than the second threshold.
[0041] Advantageously, the method comprises, before step c), a step consisting of: b) compare the temperature of the computer 4, 10 on the first channel of the computer 4, 10 with the temperature of the computer 4, 10 on the second channel of the computer 4, 10 which is redundant to the first channel, the temperature of the computer 4, 10 on the second channel being determined from the second temperature sensor 15 which is specific to the computer 4, 10; the turbomachine 3, 9 being stopped in step c), if the comparison carried out in step b) indicates that the temperature of the computer 4, 10 on the first channel is equal to the temperature of the computer 4, 10 on the second channel taking into account a predetermined tolerance, for example a tolerance of five degrees Celsius.
[0042] Such step b) is commonly referred to as a “gap test”.
[0043] Advantageously, the method generates an alert Al signaling an inconsistency between the temperature of the computer 4, 10 on the first channel and the temperature of the computer 4, 10 on the second channel, if the comparison carried out in step b) reveals a disparity greater than the predetermined tolerance between the temperature of the computer 4, 10 on the first channel and the temperature of the computer 4, 10 on the second channel.
[0044] Advantageously, when step a) is subdivided into two sub-steps a1) and a2) and when the method comprises step b), sub-step a1) is carried out before step b) and sub-step a2) is carried out after step b).
[0045] Advantageously, when the turbomachine 9 comprises a fan provided with variable-pitch blades or a propeller 12 provided with variable-pitch blades 13, step c) also consists of putting the variable-pitch blades of the fan or the variable-pitch blades 13 of the propeller 12 in the flag position. Such a variant applies here to the turboprop 9 illustrated in [Fig. 2] which comprises a propeller 12 provided with variable-pitch blades 13.
[0046] According to the first embodiment illustrated in [Fig.3], the stopping method chronologically comprises steps a), b) and c).
[0047] The method here generates an alert A1, if the comparison carried out in step b) reveals a disparity greater than the predetermined tolerance between the temperature of the computer 4, 10 on the first channel and the temperature of the computer 4, 10 on the second channel.
[0048] The computer 4, 10 stops the associated turbomachine 3, 9 (step c)), if steps a) and b) are verified.
[0049] According to the second embodiment illustrated in [Fig.4], the stopping method chronologically comprises the steps / sub-steps a1), b), a2) and c).
[0050] The parameter associated with the temperature of the computer 4, 10 which is used in sub-step a2) is here the gradient of the temperature of the computer 4, 10 as a function of time.
[0051] The shutdown method can generate an alert A1, but also an alert A2 signaling an abnormally high temperature of the computer 4, 10, if the comparison carried out in sub-step a2) indicates that the temperature gradient of the computer 4, 10 is lower than the second threshold.
[0052] The computer 4, 10 stops the associated turbomachine 3, 9 (step c)), if the steps / sub-steps a1), b) and a2) are verified.
[0053] The turbomachine 3, 9 and / or the computer 4, 10 may comprise one or more thermal fuses calibrated to stop the electrical supply of the equipment intended for restarting the turbomachine 3, 9, after the stopping of the turbomachine 3, 9 carried out in step c).
[0054] Such thermal fuses make it possible to permanently isolate these pieces of equipment from the computer 4, 10, in order to ensure that the turbomachine 3, 9 will not restart following its shutdown carried out in step c). Indeed, when the computer is subjected to fire and has already commanded the shutdown of the turbomachine, it is likely to generate signals in an untimely manner on the control circuits of the equipment during the period when it continues to be exposed to temperatures which exceed a maximum admissible temperature. The thermal fuses are calibrated to cut the corresponding circuits, and therefore inhibit any command to the equipment, before the temperature in the computer reaches a maximum admissible temperature.
[0055] The equipment concerned includes in particular the starter, the high-energy box and the electro-stop valve.
Claims
Claims
1. Method for stopping an aircraft turbomachine (3, 9) in operation in the event of a fire in a compartment (2, 8) in which the turbomachine (3, 9) is placed, the method being carried out by a non-fireproof computer (4, 10) controlling the turbomachine (3, 9) and placed in the compartment (2, 8), the method chronologically comprising the steps of: a) comparing the temperature of the computer (4, 10) or a parameter associated with the temperature of the computer (4, 10) with a predetermined threshold on a first channel of the computer (4, 10), the temperature of the computer (4, 10) or the associated parameter being determined from a first temperature sensor (14) which is specific to the computer (4, 10); c) stopping the turbomachine (3, 9), if the comparison carried out in step a) indicates that the temperature of the computer (4, 10) or the associated parameter is higher than the predetermined threshold;the method comprising before step c) a step consisting of: b) comparing the temperature of the computer (4, 10) on the first channel of the computer (4, 10) with the temperature of the computer (4, 10) on a second channel of the computer (4, 10) which is redundant to the first channel, the temperature of the computer (4, 10) on the second channel being determined from a second temperature sensor (15) which is specific to the computer (4, 10); the turbomachine (3, 9) being stopped in step c), if the comparison carried out in step b) indicates that the temperature of the computer (4, 10) on the first channel is equal to the temperature of the computer (4, 10) on the second channel taking into account a predetermined tolerance, for example a tolerance of five degrees Celsius.;
2. Stopping method according to claim 1, characterized in that step a) is subdivided into two sub-steps consisting of: a1) comparing the temperature of the computer (4, 10) with a first predetermined threshold on the first channel of the computer (4, 10); a2) comparing the parameter associated with the temperature of the computer (4, 10) with a second predetermined threshold on the first channel of the computer (4, 10); the turbomachine (3, 9) being stopped in step c), if the comparison carried out in sub-step a1) indicates that the temperature of the computer (4, 10) is greater than the first threshold, and if the comparison made in sub-step a2) indicates that the associated parameter is greater than the second threshold.
3. Stopping method according to one of the preceding claims, characterized in that the parameter is the gradient of the temperature of the computer (4, 10) as a function of time.
4. Stopping method according to one of the preceding claims, characterized in that the method generates an alert A1 signaling an inconsistency between the temperature of the computer (4, 10) on the first channel and the temperature of the computer (4, 10) on the second channel, if the comparison carried out in step b) reveals a disparity greater than the predetermined tolerance between the temperature of the computer (4, 10) on the first channel and the temperature of the computer (4, 10) on the second channel.
5. Stopping method according to claim 2 or one of claims 3 or 4 when they depend on claim 2, characterized in that sub-step a1) is carried out before step b) and sub-step a2) is carried out after step b).
6. Stopping method according to claim 5, characterized in that the method generates an alert A2 signaling an abnormally high temperature of the computer (4, 10), if the comparison carried out in sub-step a2) indicates that the associated parameter is lower than the second threshold.
7. Stopping method according to one of the preceding claims, characterized in that step c) also consists of putting the variable-pitch blades of the fan or the variable-pitch blades (13) of the propeller (12) in the flag position, when the turbomachine (9) comprises a fan provided with variable-pitch blades or a propeller (12) provided with variable-pitch blades (13).