Automatic Detection of the Hardware Configuration of On-Board Devices in an Aircraft

Abstract

The present invention relates to a method for detecting the hardware configuration of a device intended to be mounted on an aircraft turbine and controlled by a dual-channel protection calculator (8), said protection calculator comprising a power supply capable of powering the device, a first measurement box (16) capable of measuring a first voltage V s1 at the output of the device, and a second measurement box (18) capable of measuring a second voltage V s2 at the output of the device: a) sending a control voltage V c to the input of the device; b) measuring the first voltage V s1 and the second voltage V s2 ; c) inferring the hardware configuration of the device based on the values of the measured first voltage V s1 and second voltage V s2 .

Description

Field of the Invention

[0001] The present invention relates to an on-board device in an aircraft, and more particularly, a fuel regulation device, especially for turbines such as turbojet engines or turboprop engines. Background Art

[0002] There are several on-board computers in an aircraft, the purpose of which is to monitor various on-board devices in order to ensure the proper operation of the various on-board devices. In particular, devices whose malfunction is critical, such as turbines, need to be monitored by two computers, one of which is dedicated to redundancy and is used in the event of a malfunction of the first computer.

[0003] These computers are also known as protection computers. One of their tasks is to prevent fuel from flowing to the turbine in the event of a malfunction being identified, in order to avoid catastrophic events.

[0004] From one turbine model to another, depending on its architecture, it may be necessary for the protection computer to control the fuel metering unit (FMU). In each FMU, the fuel flow is metered by a metering valve, commonly known as the fuel metering valve (FMV). This FMV is controlled by the electronic engine control (EEC) computer of the turbine via a servo valve, and the servo valve evaluates the metered mass flow rate Q through the following formula for calculating the flow rate through the orifice:

[0005] [Equation 1]

[0006]

[0007] where ΔP is the pressure difference between the upstream and downstream of the FMV, S is the cross-sectional area of the orifice through which the fuel fluid passes in the FMV, ρ is the density of the fluid, and Ks is a parameter related to the FMV.

[0008] The FMV typically includes a movable element, the position of which is controlled to change the cross-sectional area of the fuel orifice. In this way, the flow rate setpoint of the control computer can be converted into a position setpoint of the movable element. This movable element can be combined with a linear variable differential transformer (LVDT). When the element translates, it is commonly referred to as a "spool".

[0009] The position of the spool, as measured by the LVDT sensor, is transmitted to the EEC control computer, which controls the movement of the spool via the servo valve. Since the pressure difference remains constant, a quantified mass flow rate depends on the position of the movable spool.

[0010] There are different models of regulating devices, which have different hardware characteristics and, therefore, in particular, require different control currents. During maintenance operations, it is also possible to replace a first FMU model with a second FMU model. Sending too high a control current can damage the control device, and sending too low a control current can affect the protection of the turbomachinery in case of malfunction.

[0011] Currently, information about the turbine architecture, namely the number, location, and FMU models used, is input into the protection application software run by the protection calculator.

[0012] Therefore, during maintenance operations, modifying the FMU model requires modifying the protection application software to avoid any operational problems.

[0013] The object of the present invention is in particular to provide a simple, effective, and economical technical solution to the problems of the prior art described above. Summary of the Invention

[0014] For this purpose, a method for detecting the hardware configuration of a device intended to be mounted on a turbine and controlled by a dual-channel protection calculator is proposed, the protection calculator comprising a power supply capable of powering the device, a first channel of a first measuring box including a first measuring box capable of measuring a first voltage V s1 at the output of the device and a second channel of a second measuring box including a second measuring box capable of measuring a second voltage V s2 at the output of the device:

[0015] a) Sending a control voltage Vc to the input of the device;

[0016] b) Measuring the first voltage V s1 and the second voltage V s2 ;

[0017] c) Inferring the hardware configuration of the device based on the values of the measured first voltage V s1 and second voltage V s2 .

[0018] For a given control voltage (Vc), the hardware configuration is associated with specific values of the first and second voltages.

[0019] When the device is, for example, an FMU, such a method implemented on the protection calculator makes it possible to automatically detect the FMU model connected to the protection calculator during the stage of powering on the device, i.e., when the device is started, and thus adapt the control current to each FMU model.

[0020] Therefore, based on the electrical characteristics of the FMU model, it is possible to infer its model. For this purpose, the voltage response to the control voltage is analyzed in order to automatically (i.e., without human intervention) infer the hardware configuration of each device.

[0021] Therefore, by performing a discriminant test of the configuration, the technical solution ensures the control of devices with heterogeneous hardware configurations while guaranteeing the prevention of unexpected malfunctions of the turbine (hazardous engine effect).

[0022] In addition, the device may be a fuel metering unit including a movable element and having one of the following hardware configurations:

[0023] - A first hardware configuration, in which the fuel metering unit includes means for measuring the position of the movable element; - A second hardware configuration, in which the fuel metering unit does not include a position measurement unit, and in which the wiring or harness wiring creates a short circuit between the control module of the protection calculator and the measurement box;

[0024] - A third hardware configuration, in which the fuel metering unit does not contain a position measurement unit, and in which the wiring or harness wiring creates an open circuit between the control module of the protection calculator and the measurement box.

[0025] The protection calculator is adapted to identify the hardware configuration of one of the three aforementioned configurations based on the values of the first voltage and the second voltage measured.

[0026] Currently, there are three physical configurations for the fuel metering unit. The first configuration is characterized by the presence of a unit for measuring the position of the fuel metering unit. This measurement unit may be, for example, a passive electrical sensor, such as an LVDT, whose input is supplied with a control voltage, and whose windings can provide two output voltages, the values of which depend on the positions of two movable rods connected to the fuel metering unit. The second and third hardware configurations do not include a unit for measuring the position of the fuel metering unit, and information related to the position of the metering device is obtained, for example, from the measurement of the flow rate and in the case of knowing the various parameters of the calculation formula [Formula 1], in particular, the pressure difference at the terminals of the metering unit. This formula correlates the flow rate with the free cross-section of the dispenser, which depends on the position of the movable unit.

[0027] In addition, the control voltage Vc is sent by the protection calculator.

[0028] In fact, the fuel metering unit is directly controlled by the protection calculator, which, in the event of a malfunction, is able to cut off the fuel supply in order to avoid any catastrophic event, such as an overspeed start of the turbine, which could lead to the bursting of the turbine disk.

[0029] Therefore, the control voltage Vc may be a DC voltage below 15V.

[0030] In particular, the measured first voltage V s1 and the second voltage V s2 are each compared with threshold values S 1 , S 2 and S 3 such that S 1 < S 2 < S 3 , in particular, where S 1 ∈ [0; 0.1×Vc], S 2 ∈ [0.8×Vc; 0.9×Vc] and S 3 ∈ [0.9×Vc; 1.1×Vc], with Vc being the control voltage.

[0031] Furthermore, the sum of the measured first voltage V s1 and the second voltage V s2 is compared with threshold values S 3 , S 4 and S 5 such that S 3 < S 4 < S 5 , in particular, where S 4 ∈ [0; 0.1×Vc], S 5 ∈ [0.9×Vc; 1.1×Vc] and S 6 ∈ [1.8×Vc; 2.2×Vc], with Vc being the control voltage.

[0032] Based on the voltages V s1 and V s2 measured at the output of the fuel metering unit and the value of the resistance of this unit, regardless of its structure, it is possible to automatically determine the hardware configuration of the unit. In other words, the voltage response of the fuel metering unit to a control voltage of 7V sent by the calculator allows the calculator to automatically identify its hardware configuration for each one when the fuel metering unit is switched on. Thus, protecting the calculator can then depend on adapting the levels of these control voltages to the hardware configuration (i.e., its model) of each fuel metering unit.

[0033] This document also relates to a calculator program, which includes instructions for implementing the method as described above when executed on a processor.

[0034] This document also relates to protecting a calculator, which includes a processor coupled to a memory such that the aforementioned program is stored on the memory. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 shows a first configuration of the fuel metering unit;

[0036] ​Figure 2 shows a first configuration of a fuel metering unit;

[0037] Figure 3 shows a first configuration of a fuel metering unit. DETAILED DESCRIPTION

[0038] During maintenance operations, replacement of the fuel metering unit (FMU) does not necessarily mean an identical replacement, so a fuel metering unit with a first hardware configuration can be replaced by a metering unit with a second hardware configuration.

[0039] Currently, three models of fuel metering units are in use, each having its own hardware configuration, as shown respectively in Figure 1 、 Figure 2 and Figure 3 as shown.

[0040] It can be seen that in the turbine, the fuel metering unit 2 is connected to a dual-channel protection calculator 8 via two separate wire harnesses 4, 6. This protection calculator 8 actually includes two independent calculators 10, 12 that communicate with each other and perform the same operations / calculations, a main calculator and a secondary calculator. In the event of a malfunction of the main calculator 10, this calculator redundancy is particularly necessary: the main calculator is then isolated, and the secondary calculator 12 then becomes responsible for controlling the equipment, in particular, the calculator of the fuel metering unit 2.

[0041] Each of the protection calculators 10, 12 includes:

[0042] - A control module 14 that is capable of sending a control voltage Vc to various devices 2 under the supervision of the protection calculator 8. This device-specific control voltage can thus power the target device 2.

[0043] - A first measurement box 16 and a second measurement box 18 that are adapted to measure the voltages V s1 and V s2 emitted at the output of the device in response to the control voltage sent by the control module 14.

[0044] In addition, although not shown in Figures 1 to 3 , the calculator includes a processor coupled to a memory, and the processor is capable of performing calculations to control various devices supervised by the protection calculator.

[0045] The first hardware configuration of the first model of the fuel metering unit 2 is characterized by the presence of a passive electrical sensor 20, which makes it possible to obtain the position of the fuel metering unit. This sensor is typically an LVDT (linear variable differential transformer) sensor and is also redundant, so that the first LVDT sensor 20 is connected to the first calculator 10 and the second LVDT sensor 22 is connected to the second calculator 12.​​

[0046] Thus, in response to the supply voltage from the control module 14 to the first channel 10 and the second channel 12 (i.e., the first calculator and the second calculator), the voltages V s1 and V s2 .

[0047] This first model is generally referred to as the Cutback FMU.

[0048] The second hardware configuration of the second fuel metering unit model 24 is different from the first hardware configuration of the first model in that there is no LVDT. Thus, compared with the first configuration, the calculator 8 does not receive any feedback from the LVDT. In fact, as can be seen in Figure 2 , the output voltage of the power supply unit of the control module is equal to the output voltage of the fuel metering unit. In other words, an intentional short circuit is implemented on the two channels protecting the calculators 10, 12. The terminals of the control module 14 are directly connected to the terminals of the measurement boxes 16, 18. The short circuit is implemented at the level of the wire harness 4 or directly at the level of the device, i.e., the fuel metering unit 24. Thus, the second hardware configuration is a hardware configuration in which the fuel metering unit 24 does not include a position measurement unit 20 and its wiring or wire harness wiring creates a short circuit between the control module 14 of the dual-channel protected calculator 8 and the measurement boxes 16, 18.

[0049] Similar to the second configuration, the third hardware configuration of the third fuel metering unit model 26 does not include an LVDT. The third hardware configuration 26 is different from the second hardware configuration in that an autonomous open circuit is created on the two channels 10, 12. In fact, as can be seen in Figure 3 , in the absence of an LVDT, the calculator 8 no longer receives a signal from the LVDT sensor. In addition, compared with the second configuration 24, the control module 14 is connected to the first terminal 28 and the second terminal 30 of the fuel metering unit 26 that are isolated from each other so as to form an open circuit. The dual-channel measurement boxes 10, 12 are not connected to the control module 14 but are connected to the third terminal 32, the fourth terminal 34, and the fifth terminal 36 that are isolated from each other or alternatively connected to a common ground. This third design 26, generally referred to as the baseline, is characterized by a fuel metering unit 24 that does not include a position measurement unit. In addition, its wiring or wire harness wiring of this third model 26 creates an open circuit between the control module 14 of the dual-channel protected calculator 8 and the measurement boxes 16, 18.

[0050] The method for detecting the model of the fuel metering unit used is mainly based on the voltage measured by the measurement box under the 7 VDC power supply of the fuel metering unit.

[0051] Its implementation is a calculator program including instructions for implementing this detection process when executed on a processor. In particular, it is stored in the memory of the calculator coupled to the processor, such that it can be executed by the protected calculator. In this way, the detection of the hardware configuration of the fuel metering unit connected to the protected calculator is automatic.

[0052] The detection method includes, in a first step, sending a control voltage Vc to the device, namely, at the input of the fuel metering units 2, 24, 26. This control voltage Vc is a DC voltage equal to 7V.

[0053] In a second step, the measuring boxes 16, 18 measure the first and second secondary voltages V s1 and the second secondary voltage V s2 .

[0054] Based on the measured voltages V s1 and V s2 , the hardware configuration of the fuel metering units 2, 24, 26, namely, the model used, is inferred. In fact, the characteristics of the hardware configuration presented above are the following voltage values:

[0055] [Table 1]

[0056] Hardware configuration of the metering unit Configuration 1 Configuration 2 Configuration 3 <![CDATA[V S1 or V S2 > ＜6V ＜7V ＜0V <![CDATA[V S1 +V S2 > ＜7V ＜14V ＜0V

[0057] Thus, the first configuration of the fuel metering unit 2 including the LVDT sensor 20 (the output signal of which is measured) is characterized by the measured voltages V s1 and V s2 , such that V S1 < 6V and V S2 < 6V and V S1 + V S2 ~ 7V.

[0058] The second configuration of the fuel element 24 without an LVDT is characterized by the measured voltages V s1 and V s2 , such that V S1 ~ 7V and V S2 ~ 7V and V S1 + V S2 ~ 14V. In fact, due to the self-short circuit, the voltages V s1 and V s2 are both approximately equal to the DC voltage delivered by the control module, namely, a DC voltage of 7V.

[0059] The second configuration of the fuel element 26 without an LVDT is characterized by the measured voltages V s1 and V s2 , such that V S1 ~ 0V and VS2 ~0V and V S1 +V S2 ~0V. In fact, due to the open circuit by itself, the voltage V s1 and V s2 are both approximately zero.

[0060] Therefore, the voltages V s1 and V s2 are compared with the thresholds S 1 , S 2 and S 3 having the following values respectively: 0V, 6V and 7V. Alternatively or additionally, the sum of the measured voltages is compared with the thresholds S 3 , S 4 and S 5 having the following values respectively: 0V, 7V and 14V.

[0061] Generally, the values of the thresholds can be respectively in the following ranges:

[0062] -S 1 ∈[0; 0.1×Vc], S 2 ∈[0.8×Vc; 0.9×Vc] and S 3 ∈[0.9×Vc; 1.1×Vc],

[0063] -S 4 ∈[0; 0.1×Vc], S 5 ∈[0.9×Vc; 1.1×Vc] and S 6 ∈[1.8×Vc; 2.2×Vc].

[0064] Preferably, when the device of the aircraft is turned on, all steps of this method are executed by the protection calculator.

Claims

1. A method for detecting the hardware configuration of a device (2) intended to be mounted on an aircraft turbine and controlled by a dual-channel protection calculator (8), said protection calculator comprising two independent calculators (10, 12) that communicate with each other and perform the same operations / calculations, a main calculator and a secondary calculator, each of the two independent calculators (10, 12) comprising a power supply capable of powering said device, a first measurement box (16) capable of measuring a first voltage (V s1 ) at the output of said device, and a second measurement box (18) capable of measuring a second voltage (V s2 ) at the output of said device: a) Send a control voltage (Vc) to the input of the device (2); b) Measure the first voltage (V s1 ) and the second voltage (V s2 ); c) Infer the hardware configuration of the device (2) based on the values of the measured first voltage (V s1 ) and the second voltage (V s2 ). wherein, the device is a fuel metering unit (2, 24, 26) including a movable element and having one of the following hardware configurations: - The first hardware configuration, wherein the fuel metering unit (2) includes a position measurement unit (20) for the movable element, wherein a first voltage (V s1 ) is less than 6 V or a second voltage (V s2 ) is less than 6 V, and the sum (V s1 ) of the first voltage (V s2 ) and the second voltage (V s1 + V s2 ) is less than 7 V; - A second hardware configuration, in which the fuel metering unit (24) does not include a position measurement unit (20), and in which a short circuit is established between the control module (14) of the protection calculator (8) and the measurement boxes (16, 18) by means of wiring or harness wiring, where a first voltage (V s1 ) is less than 7 V or a second voltage (V s2 ) is less than 7 V, and the sum (V s1 ) of the first voltage (V s2 ) and the second voltage (V s1 + V s2 ) is less than 14 V; - A third hardware configuration, wherein the fuel metering unit (26) does not include a position measurement unit (20), and wherein the wiring or harness wiring creates an open circuit between the control module (14) of the protection calculator (8) and the measurement boxes (16, 18), where a first voltage (V s1 ) is less than 0 V or a second voltage (V s2 ) is less than 0 V, and the sum (V s1 ) of the first voltage (V s2 ) and the second voltage (V s1 + V s2 ) is less than 0 V.

3. The method according to claim 1, characterized in that, the three hardware configurations have the same resistance value.

6. The method according to any one of the preceding claims, characterized in that, send the control voltage (Vc) through the protection calculator (8).

9. The method according to claim 1, characterized in that, the control voltage (Vc) is a DC voltage less than 15V.

12. The method according to claim 1, characterized in that, Compare the measured first voltage (V s1 ) and the second voltage (V s2 ) with the thresholds S 1 , S 2 and S 3 respectively, such that S 1 < S 2 < S 3 , in particular, where S 1 ∈ [0; 0.1×Vc], S 2 ∈ [0.8×Vc; 0.9×Vc] and S 3 ∈ [0.9×Vc; 1.1×Vc], where Vc is the control voltage.

15. The method according to claim 1, characterized in that, The sum (V s1 ) of the measured first voltage (V s2 ) and the second voltage (V s1 +V s2 ) is compared with thresholds S 3 , S 4 and S 5 such that S 3 < S 4 < S 5 , in particular, where S 4 ∈ [0; 0.1×Vc], S 5 ∈[0.9×Vc; 1.1×Vc] and S 6 ∈ [1.8×Vc; 2.2×Vc], where Vc is the control voltage.

18. A calculator program product, comprising a calculator program including instructions for implementing the method according to any one of claims 1 to 6 when executed on a processor.

19. A protection calculator, comprising a processor coupled to a memory such that the program according to claim 7 is stored in the memory.

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