Method and device for optimizing climbing phase of aircraft, in particular in terms of fuel consumption

Abstract

A method (P) for optimizing a climb phase, which is repeatedly implemented during the climb phase of an aircraft, comprises: an acquisition step (E1) for acquiring a current value of an input parameter; a step (E2) of determining a current optimized DTflex value from the current value of the input parameter and from the optimized DTflex values recorded in the database (3); and a transmission step (E3) for transmitting the determined current optimized DTflex value to the user system in order to control the thrust of the aircraft, said method (P) making it possible to continuously adjust the optimized DTflex value during the climb phase in such a way that it corresponds to the current condition of the aircraft in order to maximize its performance, in particular in terms of fuel consumption.

Description

Technical Field

[0001] The invention relates to a device and a method for optimizing the climb phase of an aircraft, such as a cargo aircraft, in particular with regard to fuel consumption. Background Art

[0002] The engines of an aircraft are subject to higher stresses when operating at very high engine speeds, i.e. when producing close to the maximum available thrust. This is particularly true in the phases associated with take-off and climb, during which considerable thrust is required. These stresses are caused by the higher temperatures of the exhaust gases produced at higher engine speeds. It is therefore desirable to limit the use of the maximum available thrust as much as possible, in order to save the engine, limit its maintenance costs and increase its life.

[0003] Various methods are known that allow the thrust to be limited during the phases associated with take-off and climb of an aircraft such as a cargo aircraft.

[0004] For example, one conventional approach involves using a predefined thrust limit during takeoff. The aircraft then takes off using a certain set percentage of its maximum available thrust, reaches a predetermined altitude, and then continues its climb at normal thrust. However, the use of set thrust limits is not applicable to a wide range of takeoff weights.

[0005] Another method implemented by the flight management system (FMS) of the aircraft, known as the "autoderate" method or the "flex-temp" method (flex-temp stands for flexible temperature), consists in calculating a virtual temperature (called the flexible temperature) to be taken into account by the systems of the aircraft instead of the actual ambient temperature. In particular, the thrust available to the aircraft depends on the ambient temperature. Above a certain temperature, the higher the ambient temperature, the lower the maximum available thrust. Therefore, where possible, a virtual temperature higher than the actual ambient temperature is calculated based on certain characteristics (weight of the aircraft, altitude desired to be reached, reference ambient temperature, etc.) and used in order to allow the aircraft to take off with reduced thrust. Although this method creates flexibility, since it allows the desired reduced thrust to be applied during take-off to be chosen, in particular according to the weight of the aircraft, it leads to the use of a constant flexible temperature, which is not the most appropriate at every point during the climb phase.

[0006] In any case, these known methods are suboptimal in terms of cost, in particular in terms of fuel consumption. Specifically, they result in the use of sometimes ineffective thrust during the climb phase, which results in excessive fuel consumption.

[0007] The known solutions are therefore not entirely satisfactory. Summary of the invention

[0008] The object of the present invention is to remedy the above-mentioned drawbacks. The present invention relates to a method for optimizing a climb phase of an aircraft, the method comprising determining an optimized DT corresponding to a temperature difference for controlling the thrust of the aircraft. flex value.

[0009] According to the invention, the method comprises at least the following series of steps repeatedly implemented by an avionics computer during the climb phase:

[0010] - an acquisition step for acquiring current values ​​of input parameters, the input parameters including at least the weight of the aircraft, the speed of the aircraft, the altitude of the aircraft and a reference temperature;

[0011] - a determination step for determining the optimal DT according to the current values ​​of the input parameters obtained in the acquisition step and according to the optimized DT recorded in a database integrated into the avionics computer flex value to determine the currently optimized DT flex value, the database has been optimized by DT flex A value is pre-created in association with each input parameter combination of a predefined number of input parameter combinations; and

[0012] - a transmission step for transferring the currently optimized DT determined in the determination step to flex The value is transferred to the currently optimized DT flex Value to control the thrust of the vehicle.

[0013] Therefore, in view of the present invention, the optimized DT can be continuously adjusted during the climbing phase. flex This adjustment makes it possible to modulate the thrust of the aircraft in order to maximize its performance in terms of cost, in particular in terms of fuel consumption.

[0014] Furthermore, in a particular embodiment, the method comprises a preliminary step of implementing a creation method to create said database, said preliminary step comprising a set of sub-steps implemented for each of said input parameter combinations and comprising:

[0015] - a first calculation sub-step, for calculating, using the input parameters in question, sets of climb parameters characterizing the climb phase of the aircraft, the climb parameters comprising at least the fuel flow rate of the aircraft, the net thrust of the aircraft and the drag of the aircraft, for a predefined number of DT flex Each DT in the value flex Values ​​to calculate a set of climb parameters;

[0016] - a second calculation sub-step of calculating, for each set of climb parameters calculated in the first calculation sub-step, at least one value representative of the cost of the climb phase; and

[0017] - Selection sub-step for choosing the DT with the minimum cost in the climbing phase flex value, and used to convert this DT flex The value is the optimized DT associated with the input parameter combination in question. flex The values ​​are recorded in the database.

[0018] Advantageously, the value representing the cost of the climbing phase is calculated using the following mathematical formula:

[0019]

[0020] in:

[0021] is the specific energy of the aircraft;

[0022] FF is the fuel flow rate of the aircraft;

[0023] λ ref is the reference factor; and

[0024] V is the speed of the vehicle.

[0025] Furthermore, in a first calculation sub-step, DT for which a set of climb parameters is calculated flex Values ​​included in the minimum DT flex Value and maximum DT flex Value between, minimum DT flex The value corresponding to DT where the thrust is maximum flex value, and the maximum DT flex The value corresponds to the DT at which the aircraft's climb rate is equal to the predefined minimum climb rate flex value.

[0026] In a particular embodiment, the method comprises a verification step, performed after the determination step, for:

[0027] - based on the predetermined exhaust gas temperature value, determining that the currently optimized DT determined in the determining step should be used flex The theoretical value of the exhaust temperature of the aircraft is obtained;

[0028] - comparing the theoretical value of the exhaust gas temperature with a limit value of the exhaust gas temperature; and

[0029] If the theoretical value of the exhaust gas temperature is lower than or equal to the exhaust gas temperature limit value, the currently optimized DT is transmitted in a transmission step. flex value; and

[0030] If the theoretical value of the exhaust temperature is higher than the limit value of the exhaust temperature, then in the transmission step the DT in which the theoretical value of the exhaust temperature is equal to the limit value of the exhaust temperature is transmitted flexThe value is the current optimized DT flex value.

[0031] Furthermore, in another particular embodiment, the method comprises a measuring step, carried out before the acquiring step, for measuring the current value of the input parameter and transmitting said current value of the input parameter to the avionics computer.

[0032] The invention also relates to a method for optimizing a climb phase of an aircraft, for determining an optimized DT corresponding to a temperature difference for controlling the thrust of said aircraft. flex Value device.

[0033] According to the invention, the device comprises at least one avionics computer configured to:

[0034] - obtaining current values ​​of input parameters, which include at least the weight of the aircraft, the speed of the aircraft, the altitude of the aircraft and a reference temperature;

[0035] - for determining the optimal DT according to the current values ​​of the input parameters obtained in the obtaining step and according to the optimized DT recorded in a database integrated into the avionics computer flex value to determine the currently optimized DT flex value, the database has been optimized by DT flex A value is pre-created in association with each input parameter combination of a predefined number of input parameter combinations; and

[0036] - The current optimized DT determined in the determination step flex The value is transferred to the currently optimized DT flex Value to control the thrust of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings will make it easy to understand how the invention can be implemented. In these drawings, the same reference numerals represent similar elements.

[0038] Figure 1 is a schematic perspective view of an aircraft including a device for optimizing the climb phase.

[0039] Figure 2 is a block diagram of the method used to optimize the climb phase.

[0040] Figure 3 is to demonstrate the use of creating an optimized DT associated with a combination of input parameters flex Schematic diagram of the method of the database of values.

[0041] Figure 4 Is displayed by Figure 3The method creates a graph of an example of some of the information contained in the database.

[0042] Figure 5 is a graph illustrating an example of the advantageous effect of a method for optimizing a climb phase on the rotational speed of blades of an aircraft engine relative to a conventional method.

[0043] Figure 6 is a graph illustrating one example of the advantageous effect of a method for optimizing a climb phase on the exhaust gas temperature of an aircraft engine relative to a conventional method. DETAILED DESCRIPTION

[0044] Already in Figure 1 Schematically shown in FIG. 1 is a device for optimizing the climb phase of an aircraft AC (hereinafter referred to as device 1) that allows the invention to be demonstrated. This device 1 with which the aircraft AC is equipped makes it possible to determine an optimized DT intended for controlling the thrust of the aircraft AC during the climb phase. flex value.

[0045] In the context of the present invention, and for the sake of simplicity, “climb phase” refers to the flight phase of an aircraft AC that includes take-off from the runway of an airport and the ascent phase during which the aircraft AC gains altitude (usually from 1500 feet) to reach a desired altitude called TOC altitude (TOC stands for top of climb).

[0046] In addition, DT flex The value corresponds to a conventional temperature difference allowing the generation of a setpoint for controlling the thrust of the aircraft AC. More precisely, DT flex The value corresponds to the difference between a reference temperature representing the actual ambient temperature and a virtual temperature (called flexible temperature) representing the temperature desired to be used as the ambient temperature when generating a set point for controlling the thrust of the aircraft AC. This set point is used to control the propulsion system of the aircraft AC, which comprises at least one engine, for example a turbofan engine.

[0047] The reference temperature is given by the ISA model (ISA stands for International Standard Atmosphere), which defines standard temperature and pressure, allowing to avoid variations due to geographical location and altitude.

[0048] The flexible temperature is chosen so as to take into account the minimum climb rate, i.e. the vertical speed that allows the aircraft AC to reach the TOC altitude within the desired time. Thus, depending on the climb phase, several DT flex value.

[0049] The purpose of the device 1 is to continuously determine during the climbing phase the DT which minimizes the cost of the climbing phase. flex value.

[0050] To this end, the device 1 comprises an avionics computer 2 installed on board the aircraft AC and configured to determine the currently optimized DT flex value, i.e., the DT that allows for the best aircraft performance during the climb phase flex Value. Optimized DT flex The value is referred to as a current value because it is determined based on the current parameters of the aircraft AC, as described in detail below.

[0051] In the context of the present invention, the performance of the aircraft AC is considered to be optimal when the cost of the climb phase is minimal. Depending on the embodiment in question, the cost of the climb phase may include several components. Preferably, this is a matter of fuel consumption during the climb phase. However, the cost may also take into account other criteria, such as the time required to reach the TOC altitude.

[0052] Furthermore, the avionics computer 2 preferably corresponds to a flight management system (FMS).

[0053] In a preferred embodiment, the avionics computer 2 is configured to repeatedly perform the operations described below throughout the climb phase.

[0054] To this end, the avionics computer 2 is configured to acquire current values ​​of input parameters characterizing the current condition of the aircraft AC. The input parameters include at least the following parameters: weight of the aircraft AC, speed of the aircraft AC, altitude of the aircraft AC and a reference temperature.

[0055] Some input parameters are intended to vary during the climb phase. Their current values ​​must therefore be repeatedly measured during the climb phase. Other input parameters may be predefined constants. In this case, their values ​​are stored in a memory so that they are accessible to the avionics computer 2.

[0056] In a particular embodiment, the device 1 comprises conventional measuring systems or devices with which the aircraft AC is equipped and which are able to measure the current values ​​of the input parameters in a conventional manner. These systems or devices are also able to transmit the measured current values ​​to the avionics computer 2.

[0057] Furthermore, the avionics computer 2 is configured to calculate the current values ​​of the input parameters according to the optimized DT values ​​stored in the database 3. flex value to determine the currently optimized DT flex value.

[0058] Preferably, the database 3 is integrated into the avionics computer 2. It contains optimized DT flex values, each of which is associated with a specific combination of input parameters.

[0059] By recording the optimized DT for a predefined number of input parameter combinations flex Value, pre-create database 3. The method for creating database 3 will be described in more detail in the rest of the specification.

[0060] In addition, the avionics computer 2 is configured to convert the currently optimized DT flex The value is transferred to the currently optimized DT flex The user system 4 controls the thrust of the aircraft AC using a value. This may be a matter of a conventional unit of the aircraft AC configured to control the propulsion system of said aircraft AC. For example, the user system 4 may correspond to a FADEC system (FADEC stands for Full Authority Digital Engine Control).

[0061] User system 4 is designed to use the currently optimized DT flex The optimized DT transmitted by the avionics computer 2 determines the set points of the propulsion system of the aircraft AC during the climb phase. flex The value is continuously updated throughout the climb phase in order to continuously take into account changes in the input parameters. In this way, the thrust setpoint of the aircraft AC changes with the current optimized DT flex The value is constantly adjusted.

[0062] Thus, by means of the device 1, the optimized DT can be continuously adjusted during the climbing phase. flex value so that it corresponds to the current conditions of the aircraft AC. This regulation makes it possible to modulate the thrust of the aircraft AC in order to maximize its performance in terms of cost and in particular in terms of fuel consumption.

[0063] For example, the apparatus 1 described above is configured to implement method P, a specific embodiment of which is Figure 2 In this particular embodiment, the method P comprises a series of steps E1 , E2 and E3 repeatedly implemented by the avionics computer 2 during the climb phase.

[0064] More precisely, in step E1, the current values ​​of the input parameters are obtained.

[0065] In addition, in step E2, according to the current values ​​of the input parameters obtained in step E1 and the optimized DT recorded in the database 3 flex value to determine the currently optimized DT flex value.

[0066] In addition, in step E3, the currently optimized DT determined in step E2 flex The value is transferred to the DT that can use the current optimized flexThe user system 4 uses the value to control the thrust of the aircraft AC.

[0067] In a particular embodiment, the method P can also implement the method M for creating the database 3. Figure 2 In this particular embodiment shown in , the method P therefore comprises a preliminary step E0 carried out prior to the series of steps E1 , E2 and E3 . Step E0 employs the method M to create the database 3 .

[0068] Figure 3 The method M schematically shown in FIG. 1 comprises a series of sub-steps E01, E02 and E03 for creating a database 3. For a predefined number of input parameter combinations, the method M comprises: flex A value is associated with each of the input parameter combinations.

[0069] In particular, for a given combination of input parameters and a given climb phase, the thrust sufficient to reach the TOC altitude at minimum cost can be determined analytically. This calculation can be carried out in a conventional manner, in particular using the specific energy method and optimal control theory. The DT that allows obtaining this sufficient thrust can then be derived flex This is the optimized DT associated with the input parameter combination in question. flex value.

[0070] like Figure 3 As shown, it is expected to be combined with the optimized DT flex The input parameter combinations associated with the values ​​are represented as (A1, A2, ..., Am), where m is a positive integer corresponding to the predefined number of input parameter combinations.

[0071] In a sub-step E01, sets of climb parameters characterizing the climb phase of the aircraft AC are calculated using the input parameters in question. The climb parameters include at least the fuel flow rate of the aircraft AC, the net thrust of the aircraft AC and the drag of the aircraft AC. For each input parameter combination (A1, A2, ..., Am), in a sub-step E01, sets of climb parameters are calculated. Figure 3 As shown, each group of climb parameters is represented by (B1, B2, ..., Bn), where n is a positive integer corresponding to the number of groups of climb parameters calculated for each input parameter combination.

[0072] Each set of climb parameters (B1, B2, ..., Bn) corresponds to a specific DT flex Specifically, for a given input parameter combination, there are multiple possible DT flex values ​​that make it possible to achieve the minimum climb rate to be considered during the climb phase. Figure 3 As shown, the DT of each set of climb parameters (B1, B2, ..., Bn) calculated for itflex The values ​​are represented as (D1, D2, ..., Dn) respectively.

[0073] The number of sets of climb parameters calculated for each input parameter combination, n, corresponds to the possible DTfs that are desired to be considered. lex The number of possible DT values. flex Values ​​included in the minimum DT flex Value and maximum DT flex Preferably, the minimum DT flex value (i.e., the DT for which the maximum thrust is obtained flex value) corresponds to zero, and the maximum DT flex The value corresponds to DT for which the thrust that produces the minimum climb rate to be considered in the climb phase is obtained. flex value.

[0074] As an illustrative example, for a given input parameter combination, the possible DT flex The value can be between 10°C (maximum thrust) and 30°C (thrust that produces the minimum climb rate to be considered). flex Of the values, a selection can be made to calculate the climb parameter per degree Celsius. This represents the calculation of thirty-one sets of parameters (in this case m=31).

[0075] Furthermore, in sub-step E02, a cost value representing the cost of the climbing phase is calculated for each set of climbing parameters (B1, B2, ..., Bn) calculated in sub-step E01. Figure 3 As shown, the cost values ​​calculated for each set of climb parameters (B1, B2, ..., Bn) are respectively expressed as (J1, J2, ..., Jn).

[0076] In a preferred embodiment, for a given set of climb parameters, the cost value is calculated using the following mathematical formula:

[0077]

[0078] in:

[0079] is the specific energy of the aircraft AC;

[0080] FF is the fuel flow rate of the aircraft AC;

[0081] λ ref is the reference factor; and

[0082] V is the speed of the vehicle AC.

[0083] Reference factor λ refcorresponds to the ratio between the reference fuel flow rate and the reference speed. These parameters represent the ideal flight conditions for the aircraft AC, i.e. the conditions that produce the minimum cost. The reference factor λ ref Serves as a comparison point to quantify the cost difference between the current flight conditions of the aircraft AC and the ideal flight conditions (usually the conditions sought to be achieved during the cruise phase).

[0084] Furthermore, the specific energy E of the aircraft AC can be calculated using the following mathematical formula:

[0085]

[0086] in:

[0087] V is the speed of the aircraft AC;

[0088] F N is the net thrust of the aircraft AC;

[0089] D is the drag of the aircraft AC; and

[0090] m is the weight of the aircraft AC.

[0091] In addition, in sub-step E03, for each input parameter combination (A1, A2, ...Am), the DT with the minimum cost in the climbing phase is selected. flex The selected DT flex Each of the values ​​is specific to a combination of input parameters. Figure 3 As shown, the selected DT flex The values ​​are denoted Dopt(A1), Dopt(A2), ..., Dopt(Am). They are each recorded in the database 3 each time as an optimized DT associated with a combination of input parameters specific to it. flex value.

[0092] In the preferred embodiment described above, the selected DT to be recorded in the database 3 flex The values ​​Dopt(A1), Dopt(A2), ..., Dopt(Am) correspond to the DT with the lowest cost value (J1, J2, ..., Jn) flex Value. Figure 3 As shown, the minimum cost value for each input parameter combination (A1, A2, ..., Am) is expressed as (Jmin(A1), Jmin(A2), ..., Jmin(Am)) respectively.

[0093] Thus, method M makes it possible to create a database 3 containing a large number of optimized DTflex values, each associated with an input parameter combination. The greater the number of input parameter combinations considered for creating database 3, the more it is possible to provide optimized DTflex values ​​in each case. flex value.

[0094] Figure 4 An example showing a part of the database 3 is shown in FIG. This part of the database 3 has been presented in the form of a graph comprising a plurality of curves, each curve representing an optimized DT for a specific aircraft weight. flex The relationship between the value and the height of the aircraft AC. Figure 4 The y-axis (denoted as “DT flex -opt”) gives the optimized DT in degrees Celsius (°C) flex The x-axis (denoted "ALT") gives the aircraft altitude in feet (ft).

[0095] in addition, Figure 4 Contains optimized DT for a specific reference temperature and a specific speed of the aircraft AC flex Therefore, it should be understood that this graph depicts some of the information in the database 3. The database contains a large number of optimized DT values ​​for a large number of input parameter combinations. flex This large number of optimized DT flex The value allows to cover a larger number of possible cases and to determine the DT that corresponds exactly to a particular case. flex value.

[0096] As an example, Figure 4 The graph of FIG. 1 includes a graph representing the optimized DT for aircraft weights between 300 tons (curve denoted C1) and 570 tons (curve denoted C2). flex The mass interval between two curves is therefore 10 tons. The database 3 therefore makes it possible to give an optimized DT with an accuracy of 10 tons for this input parameter (ie the weight of the aircraft AC). flex value.

[0097] exist Figure 2 In a particular embodiment shown in FIG. 1 , method P further comprises a verification step E4 implemented after step E2 but before step E3. Step E4 makes it possible to verify the currently optimized DT determined in step E2. flex The value generates an exhaust gas temperature (EGT) that exceeds a predefined limit.

[0098] To this end, step E4 determines that the currently optimized DT determined in step E3 should be used flexThe theoretical value of the exhaust temperature obtained by the avionics computer 2 is determined based on a predetermined exhaust temperature value. In particular, the exhaust temperature produced for a given thrust can be derived from the characteristics of the propulsion system of the aircraft. Thus, a predetermined value of the exhaust temperature can be provided depending on the thrust used. These predetermined values ​​can be recorded so as to be accessible to the avionics computer 2, for example in a database 3 or in another memory provided for this purpose.

[0099] Next, in step E4, this theoretical value of the exhaust gas temperature is compared with a limit value of the exhaust gas temperature. This limit value corresponds to an exhaust gas temperature value that it is not desirable to exceed. It can be defined according to the characteristics of the propulsion system of the aircraft AC and corresponds to a temperature above which it is considered that there is an increase in stress on the engines, which tends to increase their maintenance costs and / or reduce their lifespan.

[0100] In addition, in step E4, according to the result of the aforementioned comparison, the currently optimized DT determined in step E2 is flex The value is either transmitted or not transmitted to step E3.

[0101] If the theoretical value of the exhaust gas temperature is lower than or equal to the limit value of the exhaust gas temperature, the currently optimized DT determined in step E2 is flex The value is transferred to step E3.

[0102] If the theoretical value of the exhaust gas temperature is higher than the limit value of the exhaust gas temperature, the currently optimized DT transmitted to step E3 is flex The value is not the value determined in step E2. DT transferred to step E3 flex The value is the DT for which the theoretical value of the exhaust temperature is equal to the limit value of the exhaust temperature flex value.

[0103] Therefore, the currently optimized DT determined in step E2 flex As explained above, another DT flex value (which is higher than the optimized DT determined in step E2 flex value) is then used as the current optimized DT flex values ​​so that the exhaust gas temperature does not exceed predefined limit values. This makes it possible to keep costs as low as possible. Specifically, the disadvantage in fuel consumption is offset by gains in maintenance costs and the life of the engine.

[0104] Figure 5 and Figure 6 Examples of advantageous effects obtained by means of a device 1 implementing method P have been shown in a non-limiting manner in . Note that these examples relate to an aircraft having a weight equal to 560 tons.

[0105] Figure 5 is a graph showing the relationship between the rotation speed of the aircraft engine blades during the climb phase and the flight time. The y-axis (denoted N1) represents the blade rotation speed expressed as a percentage of the maximum rotation speed of the blades. The x-axis (denoted Tc) represents the flight time during the climb phase expressed in minutes, with zero indicating the beginning of the climb phase.

[0106] Figure 5 Contains two curves E1 and E2. Curve E1 represents the rotation speed of the blades of an aircraft engine using a conventional method for managing thrust. Curve E2 represents the rotation speed of the blades of an aircraft engine using method P. It should be noted that curve E1 continues to increase throughout the climb phase. In contrast, curve E2 increases until time T1 (at about 13 minutes), then decreases until time T2 (at about 19 minutes), and then rises again until the end of the climb phase. Curve E2 rejoins curve E1 after time T3 (at about 28 minutes), and the blade rotation speeds of the two curves are substantially the same starting from time T3.

[0107] Although the blade rotation speed obtained using method P is slightly higher than that obtained with the conventional method before time T1 (because a fast climb is selected), it remains much lower during the remainder of the climb phase.

[0108] Thus, method P makes it possible to reduce the rotation speed of the blades during the climbing phase, relative to conventional methods. Figure 5 In the example of , the rotation speed of the blades decreases between times T1 and T3, which represents a decrease lasting sixteen minutes in a climbing phase lasting about thirty minutes. In addition, it will be noted that at the peak of the decrease at time T2, the rotation speed of the blades is about 91% for curve E1 and about 86% for curve E2. A maximum decrease of the order of 5% is thus obtained (denoted R1).

[0109] also, Figure 6 is a graph showing the relationship between the exhaust temperature of an aircraft during a climb phase and the flight time. The y-axis (expressed as EGT) represents the exhaust temperature in degrees Celsius. The x-axis (expressed as Tc) represents the flight time during the climb phase in minutes, with zero representing the beginning of the climb phase.

[0110] Figure 6Two curves F1 and F2 are included. Curve F1 represents the exhaust temperature of an aircraft using a conventional method for managing thrust. Curve F2 represents the exhaust temperature of an aircraft using method P. It will be noted that curve F1 remains relatively constant at a value approximately equal to 850° C. throughout the climb phase. In contrast, curve F2 is relatively constant at approximately 850° C. until time T4 (at approximately 13 minutes), then decreases until time T5 (at approximately 18 minutes), then increases until time T6 (at approximately 27 minutes), from which time it effectively rejoins curve F2.

[0111] Thus, method P also makes it possible to reduce the exhaust gas temperature during the ramp-up phase relative to the conventional method. Figure 6 In the example of FIG. 1 , the exhaust temperature decreases between times T4 and T6, which represents a decrease over a period of approximately fourteen minutes in a ramp-up phase lasting approximately thirty minutes. Furthermore, it should be noted that at the peak of the decrease at time T5, the exhaust temperature of curve F2 is approximately 790° C. Thus, a maximum decrease (denoted R2) of the order of 60° C. is obtained relative to the exhaust temperature produced using conventional methods.

[0112] Note that, in the example considered above, method P allows saving of about 73 kg of fuel relative to a conventional climb phase. Of course, this gain varies according to the aircraft and the flight conditions in question.

[0113] The apparatus 1 implementing the method P described above has many advantages. In particular:

[0114] - it allows minimizing the costs of the climb phase, especially in terms of fuel consumption;

[0115] - it is suitable for implementation in various climb phase configurations; and

[0116] - It is simple and cheap to implement.

Claims

1. A method for optimizing the climb phase of an aircraft (AC), said method comprising determining an optimized DT corresponding to a temperature difference for controlling the thrust of said aircraft (AC) flex value, The method comprises at least the following series of steps repeatedly performed by an avionics computer (2) during the climb phase: - an acquisition step (E1) for acquiring current values ​​of input parameters, said input parameters comprising at least the weight of said aircraft (AC), the speed of said aircraft (AC), the altitude of said aircraft (AC) and a reference temperature; - a determination step (E2) for determining the current value of the input parameter obtained in the acquisition step (E1) and the optimized DT recorded in a database (3) integrated in the avionics computer (2); flex value to determine the currently optimized DT flex value, the database (3) has been obtained by optimizing DT flex The value is pre-created in association with each input parameter combination of a predefined number of input parameter combinations; as well as - a transmission step (E3) for transmitting the currently optimized DT determined in the determination step (E2) flex The value is transferred to the currently optimized DT flex A user system (4) is provided to control the thrust of the aircraft (AC).

2. The method according to claim 1, The method comprises a preliminary step (E0) of implementing a creation method (M) to create the database (3), the preliminary step (E0) comprising a set of sub-steps implemented for each of the input parameter combinations and comprising: - a first calculation sub-step (E01) of calculating, using the input parameters in question, sets of climb parameters characterizing the climb phase of the aircraft (AC), said climb parameters comprising at least the fuel flow rate of the aircraft (AC), the net thrust of the aircraft (AC) and the drag of the aircraft (AC), for a predefined number of DT flex Each DT in the value flex Values ​​to calculate a set of climb parameters; - a second calculation sub-step (E02) of calculating, for each set of climb parameters calculated in said first calculation sub-step (E01), at least one value representative of the cost of said climb phase; and - A selection sub-step (E03) for selecting the DT with the minimum cost in the climbing phase flex value and is used to convert the DT flex The value is the optimized DT associated with the input parameter combination in question. flex The values ​​are recorded in said database (3).

3. The method according to claim 2, The value J representing the cost of the climbing phase is calculated using the following mathematical formula: in: is the specific energy of the vehicle (AC); FF is the fuel flow rate of the aircraft (AC); λ ref is the reference factor; as well as V is the speed of the vehicle (AC).

4. The method according to any one of claims 2 and 3, in, In the first calculation sub-step (E01), a set of climbing parameters DT is calculated for it. flex Values ​​included in the minimum DT flex Value and maximum DT flex value, the minimum DT flex The value corresponding to DT where the thrust is maximum flex value, and the maximum DT flex The value DT corresponds to the aircraft (AC) having a climb rate equal to a predefined minimum climb rate flex value.

5. A method as claimed in any one of the preceding claims, The method comprises a verification step (E4) performed after the determination step (E2), for: - based on a predetermined exhaust gas temperature value, determining that the currently optimized DT determined in the determining step (E2) should be used flex a theoretical value of the exhaust gas temperature of the aircraft (AC) obtained by - comparing the theoretical value of the exhaust gas temperature with a limit value of the exhaust gas temperature; and If the theoretical value of the exhaust gas temperature is lower than or equal to the limit value of the exhaust gas temperature, then in the transmission step (E3) the currently optimized DT is transmitted. flex value; and If the theoretical value of the exhaust temperature is higher than the limit value of the exhaust temperature, then in the transmission step (E3) the theoretical value of the exhaust temperature equal to the limit value of the exhaust temperature DT is transmitted. flex The value is used as the current optimized DT flex value.

6. A method as claimed in any one of the preceding claims, The method comprises a measurement step (E5) implemented before the acquisition step (E1) for measuring the current value of the input parameter and transmitting the current value of the input parameter to the avionics computer (2).

7. A method for optimizing the climb phase of an aircraft (AC), for determining an optimized DT corresponding to a temperature difference for controlling the thrust of said aircraft (AC) flex Value device, The device comprises at least one avionics computer (2), the at least one avionics computer being configured to: - obtaining current values ​​of input parameters, said input parameters comprising at least the weight of said aircraft (AC), the speed of said aircraft (AC), the altitude of said aircraft (AC) and a reference temperature; - according to the current values ​​of the input parameters obtained in the obtaining step (E1) and according to the optimized DT recorded in the database (3) integrated in the avionics computer (2) flex value to determine the currently optimized DT flex value, the database (3) has been obtained by optimizing DT flex A value is pre-created in association with each input parameter combination of a predefined number of input parameter combinations; and - the currently optimized DT determined in the determination step (E2) flex The value is transferred to the currently optimized DT flex A user system (4) is provided to control the thrust of the aircraft (AC).

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