Aircraft fuel pressure indicating system

Abstract

The invention discloses an aircraft fuel pressure indicating system. The aircraft fuel pressure indicating system comprises a fuel pressure measuring device installed in a fuel tank of an aircraft, and the fuel pressure measuring device comprises a mechanical interface, an electrical interface and a capacitive pressure sensor; the pressure guide pipeline is used for conducting fuel oil at an outlet of a fuel oil pump or an oil filling stop valve into the fuel oil pressure measuring device; the fuel pressure measuring cable penetrates through the wall of the fuel tank and is used for transmitting a fuel pressure signal measured by a capacitive pressure sensor of the fuel pressure measuring device to a fuel signal processor located outside the fuel tank.

Description

Technical Field

[0001] The invention belongs to the field of aircraft design, and in particular relates to an aircraft fuel pressure indicating system. Background Art

[0002] An aircraft's fuel indicator system typically includes fuel quantity, fuel temperature, and fuel pressure indicators. The fuel pressure indicator system provides a higher-level control system with fuel pressure signals at the outlets of all fuel pumps, indicating the operating status of each pump to the pilot. It also provides fuel pressure signals within each tank's pressure refueling line, indicating the open / close status of each tank's refueling shut-off valve to maintenance personnel.

[0003] An aircraft fuel pressure indicator system typically consists of a fuel pump pressure indicator, a refueling shutoff valve pressure indicator, the necessary mounting brackets, pressure measurement piping, necessary mounting clamps and brackets, and a host computer for processing the pressure indicator signals. Traditional aircraft pressure indicators typically use mechanical pressure indicators, which sense fuel pressure changes via an internal spring.

[0004] Because pressure transmitters are electrically connected to the fuel system or avionics system, to prevent cables from introducing ignition sources into the fuel tank, they are typically mounted externally, typically on the main lift pod or the leading and trailing edges of the wings. The fuel pump is installed inside the aircraft's fuel tank. A fuel pressure line typically extends from the pump outlet and connects to one end of a frame connector on the aircraft's fuel tank structure. The fuel pressure transmitter is mounted externally on the other end of the frame connector. Similarly, a fuel pressure line typically extends from the refueling shutoff valve inside the fuel tank, connecting to the pressure transmitter via a frame connector.

[0005] In this type of solution, the installation of the pressure sensor requires various structural brackets and parts, which increases aircraft weight and increases the number of structural openings, compromising structural strength. Furthermore, moisture and impurities in the fuel can accumulate at the pressure sensor's measurement port, affecting the pressure sensor's accuracy and, in turn, impacting aircraft dispatchability.

[0006] Therefore, there is a need in the art for an improved aircraft fuel pressure indicating system. Summary of the Invention

[0007] The present invention provides an aircraft fuel pressure indicating system, which is used for monitoring the pressure status of an aircraft fuel pump outlet and a refueling shut-off valve outlet and transmitting signals.

[0008] In one embodiment, a capacitive fuel pressure sensor replaces a traditional mechanical pressure signal. Installing the capacitive fuel pressure sensor inside the fuel tank avoids the risk of rotor explosion and eliminates the need for drilling holes in the structure, thereby preventing oil leaks caused by insufficient sealing.

[0009] In a preferred embodiment, the pressure sensor integrates an electrical interface and a mechanical interface for connection to the pressure lead line. During installation, the mechanical interface, which fits the pressure lead line, is positioned high to prevent freezing or accumulation of impurities in the fuel in cold environments from affecting pressure measurement. This also ensures that condensation at the electrical interface flows down the cable, preventing accumulation there and affecting signal transmission.

[0010] In a preferred embodiment, the capacitive fuel pressure sensor excitation and feedback cables reuse the fuel level measurement cable design. This eliminates the need for additional in-tank ignition source protection for the cables. The sensor shares a common shielding layer with the fuel level measurement cable, reducing the weight associated with the additional shielding layer. Furthermore, the cables share the same installation path as the fuel level measurement cable, eliminating the need for additional wiring channels.

[0011] In one embodiment of the present invention, an aircraft fuel pressure indicating system is provided, comprising: a fuel pressure measuring device installed in an aircraft fuel tank, the fuel pressure measuring device including a mechanical interface, an electrical interface, and a capacitive pressure sensor; a pressure supply line, a first end of the pressure supply line being located at a fuel pump outlet or on a refueling shut-off valve of the fuel tank, a second end of the pressure supply line being connected to the mechanical interface of the fuel pressure measuring device, and configured to conduct fuel at the fuel pump outlet or the refueling shut-off valve to the fuel pressure measuring device; and a fuel pressure measuring cable, the fuel pressure measuring cable being connected to the electrical interface of the fuel pressure measuring device and passing through a wall of the fuel tank, and configured to transmit a fuel pressure signal measured by the capacitive pressure sensor of the fuel pressure measuring device to a fuel signal processor located outside the fuel tank.

[0012] In one aspect, the mechanical interface includes a pipeline thread interface for adapting and connecting with the pressure-conducting pipeline.

[0013] In one aspect, the fuel pressure measuring device is mounted on a rib plate on the inner wall of the fuel tank via a bracket.

[0014] In one aspect, the fuel pressure measuring device is located above the pressure-conducting pipeline, and the electrical interface is higher than the mechanical interface and the pressure-conducting pipeline.

[0015] In one aspect, the fuel pressure measurement cable passes through a through-frame hole on the fuel tank to reach the outside of the fuel tank.

[0016] In one aspect, the fuel pressure measurement cable and the fuel quantity measurement cable share the frame hole.

[0017] In one aspect, the fuel pressure measurement cable includes an excitation cable and a feedback cable for the capacitive pressure sensor.

[0018] On the one hand, the fuel signal processor includes a fuel remote data concentrator (FRDC), which converts the fuel pressure signal measured by the capacitive pressure sensor from an analog quantity to a digital quantity, and transmits the digital fuel pressure signal to a fuel computer (FQC), which determines that the measured fuel pressure signal is a high pressure / low pressure discrete quantity.

[0019] In one aspect, the fuel computer sends a fuel pump high / low pressure discrete to the avionics system.

[0020] On the one hand, the fuel computer determines the high / low pressure discrete amount of the refueling shut-off valve, and determines whether the fuel pressure of the refueling shut-off valve is normal based on the high / low pressure discrete amount of the refueling shut-off valve. If the fuel pressure of the refueling shut-off valve is abnormal, the FQC generates a refueling alarm signal and provides the refueling alarm signal to a refueling control panel (RDCP). BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. 1 is a schematic diagram of the architecture of a fuel pressure indicating system according to an embodiment of the present invention.

[0022] Figure 2 FIG. 4 is a signal transmission path of a fuel pressure indicating system according to an embodiment of the present invention.

[0023] Figure 3 FIG. 1 is a schematic diagram of a fuel pressure measuring device according to an embodiment of the present invention.

[0024] Figure 4 FIG. 1 is a schematic assembly diagram of a fuel pressure measuring device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to specific embodiments and drawings, but the scope of protection of the present invention should not be limited thereto.

[0026] Aircraft typically have one or more fuel tanks, such as fuselage tanks and wing tanks, to store sufficient fuel to meet flight needs. Each tank may be equipped with one or more fuel pumps to transfer fuel from the tank to the engine. Large tanks are often equipped with multiple fuel pumps, and aircraft fuel systems are often designed with redundancy. Even if a fuel pump fails, the remaining fuel pumps can continue to operate, ensuring a normal fuel supply to the engine.

[0027] Engines require stable fuel pressure to operate properly. Low fuel pressure can lead to insufficient fuel supply, reduced engine power, or even stalling. Therefore, each tank's fuel pump is equipped with a fuel pressure sensor to monitor its operating status. By measuring fuel pressure, it's possible to detect proper fuel pump operation and any issues like fuel line blockages. If fuel pressure falls below the normal range, it could indicate a fuel pump malfunction or insufficient fuel. If fuel pressure suddenly increases, it could indicate a fuel line blockage preventing fuel from flowing properly, requiring prompt inspection and repair.

[0028] In addition, aircraft have refueling shut-off valves that control the flow of fuel into the fuel tanks. During refueling, when the fuel level in the tank reaches a predetermined level, the shut-off valve automatically closes, stopping the flow of fuel into the tank and preventing spills. Each fuel tank may have its own independent shut-off valve, each equipped with a fuel pressure sensor to monitor its status.

[0029] Figure 1 FIG. 1 is a schematic diagram of the architecture of a fuel pressure indicating system according to an embodiment of the present invention. Figure 1 Three fuel tanks 110, 120, and 130 are shown. By way of example and not limitation, tank 120 may be a fuselage tank, and tanks 110 and 130 may be wing tanks. In other embodiments, a different number of tanks or tanks located in different locations may be included. Each tank may have one or more fuel pumps 112, such as DC or AC fuel pumps, for transferring fuel from the tank to the engine or auxiliary power unit. Furthermore, each tank may have a refueling shutoff valve 114 for controlling the flow of fuel into the tank.

[0030] In one embodiment of the present invention, each fuel pump or refueling shut-off valve may be equipped with a capacitive pressure sensor 116 to monitor the fuel pressure at the corresponding fuel pump or refueling shut-off valve. Capacitive pressure sensor 116 may be incorporated into a fuel pressure measuring device, which can be mounted within the fuel tank via a bracket. A capacitive pressure sensor utilizes a capacitive sensing element to convert the measured pressure into an electrical output proportional to the measured pressure. Typically, a metal film or metal-plated film serves as one electrode of a capacitor. When the film deforms in response to pressure, the capacitance formed between the film and the fixed electrode changes, resulting in an electrical signal output proportional to the voltage.

[0031] According to one embodiment of the present invention, the fuel pump outlet pressure and the refueling shut-off valve outlet pressure are both measured using a capacitive fuel pressure sensor. The capacitive fuel pressure sensor is mounted on the inner rib of the fuel tank via a mounting bracket, close to the corresponding fuel pump / refueling shut-off valve installation position.

[0032] The fuel pressure indication system may further include a fuel pressure measurement cable 118, which passes through a through-frame hole on the fuel tank and reaches the outside of the fuel tank, and is used to transmit the fuel pressure signal measured by the capacitive pressure sensor 116 to a fuel signal processor located outside the fuel tank, such as a fuel remote data concentrator (FRDC). Figure 1 1 and 2. The fuel pressure measurement cables 118 of a single fuel tank are shown as being separated. However, it should be understood that the fuel pressure measurement cables 118 of the same fuel tank can be routed to the outside of the fuel tank via the same fuel tank frame hole.

[0033] In one embodiment, the fuel pressure measurement cable 118 can share a common frame hole with the fuel quantity measurement cable. In aircraft fuel monitoring, a capacitive sensor is typically used to measure the fuel level, and the fuel volume and fuel quantity are calculated based on the fuel tank shape and density. The capacitive sensor for fuel quantity measurement is installed within the fuel tank and transmits the measured fuel quantity signal to a signal processing device outside the tank via a fuel quantity measurement cable. The fuel quantity measurement cable passes through a frame hole in the fuel tank to a fuel remote data concentrator (FRDC) located outside the tank. The aircraft fuel pressure indication system described herein can reuse the existing fuel measurement cable, fuel remote data concentrator, fuel computer, and its communication lines in the fuel quantity indication system, eliminating the need for additional equipment.

[0034] The fuel pressure signal is sent via the fuel pressure measurement cable to the FRDC for data processing and then to the FQC. The FQC then sends the fuel pump pressure signal to the avionics system to determine the fuel pump status. The refueling pressure signal is used to determine the status of the refueling function within the system. This means that the FQC can determine the refueling status and send a refueling alarm signal to the Refueling Control Panel (RDCP) if the refueling function is abnormal.

[0035] Compared with the fuel pressure signal device installed on the outside of the fuel tank in the prior art, the fuel pressure indication solution provided by the present invention installs a capacitive fuel pressure sensor inside the fuel tank, eliminating the need to drain the fuel to the outside of the fuel tank, thus avoiding the impact of rotor explosion, and eliminating the need to open a frame hole in the structure to avoid oil leakage caused by insufficient sealing.

[0036] In a preferred embodiment, the fuel pressure measurement cable reuses the fuel quantity measurement cable design, eliminating the need for additional R&D costs for ignition source protection of the cables within the fuel tank; the fuel pressure measurement cable can share a shielding layer with the fuel quantity measurement cable, reducing the weight added by the added shielding layer; and the cable installation path is the same as the fuel quantity measurement cable, eliminating the need for additional wiring channels.

[0037] In addition, the capacitive fuel pressure sensor can be mounted on the rib inside the fuel tank via a bracket, reducing the number of structural frame openings, significantly reducing the number of parts required for pressure sensor installation, simplifying the installation steps, and reducing system weight.

[0038] Figure 2 FIG. 4 is a signal transmission path of a fuel pressure indicating system according to an embodiment of the present invention.

[0039] The FRDC 202 provides excitation for the capacitive fuel pressure sensor 201 and receives feedback signals from the pressure sensor. The fuel pressure measurement cable includes both an excitation cable and a feedback cable for the capacitive pressure sensor. The fuel pressure measurement cable can be the same type as the fuel quantity measurement cable, featuring a shield and a wear-resistant braided sleeve. To reduce cable installation steps and R&D costs, it can be a branch of the original fuel measurement cable.

[0040] FRDC 202 provides an excitation signal, such as a triangular wave or square wave, to capacitive pressure sensor 201 via an excitation cable. Fuel pressure deforms the thin-film electrode of capacitive pressure sensor 201, causing a change in capacitance between the thin-film electrode and the fixed electrode. This outputs an electrical signal related to fuel pressure (i.e., the detected fuel pressure signal). This detected fuel pressure signal is an analog quantity and is transmitted to FRDC 202 via a feedback cable in the fuel pressure measurement cable.

[0041] The FRDC 202 converts the fuel pressure signal measured by the capacitive pressure sensor from analog to digital and transmits the digital fuel pressure signal to the fuel quality computer (FQC) 203. Based on the design characteristics of the fuel pump / fuel shut-off valve outlet pressure, the FQC 203 determines whether the current outlet pressure is a high-pressure / low-pressure discrete value (high pressure = GND, low pressure = OPEN) and transmits the fuel pump's high-pressure / low-pressure discrete value (OPEN / GND) to the avionics system 204. The avionics system 204 further transmits the fuel pump's high-pressure / low-pressure discrete value (OPEN / GND) to the target system 205.

[0042] For example, the target system 205 may be an alarm system. The alarm system combines the fuel pump control command signal with the pressure signal at the fuel pump outlet to determine the fuel pump fault state (for example, the command is "pump on", but the pressure signal is "low pressure"). When the fuel pump fails, a PUMP FAULT alarm is displayed on the cockpit display.

[0043] The FQC 203 determines the high / low pressure discrete value of the fuel shutoff valve and whether the fuel pressure at the fuel shutoff valve is normal. If the fuel pressure at the fuel shutoff valve is abnormal, such as low pressure when the fuel shutoff valve is open or high pressure when the fuel shutoff valve is closed, the FQC 203 generates a refueling warning signal and provides the refueling warning signal to the refueling control panel (RDCP).

[0044] In one embodiment, when the fuel pump switch is pressed, the fuel pump starts, and high-pressure fuel is transferred through the fuel pressure line to the fuel pressure sensor. The fuel pressure sensor detects the high-pressure fuel and outputs a corresponding electrical signal to the avionics system, indicating to the pilot that the fuel pump is currently in the on state. Conversely, if the fuel pump fails to start due to a malfunction or other reasons after the fuel pump switch is pressed, the fuel pressure sensor detects low fuel pressure at the fuel pump outlet. The host computer (e.g., the warning system) determines that the fuel pump is faulty and issues a low-pressure fuel pump warning signal to the cockpit. Simultaneously, the warning light corresponding to the fuel pump switch on the cockpit's fuel overhead control panel illuminates, alerting the pilot that the fuel pump has failed and that action must be taken according to the flight manual.

[0045] In one embodiment, when a maintenance crew operates the pressure refueling switch on the refueling control panel to open the refueling shutoff valve, the connected fuel pressure sensor detects high fuel pressure and sends a signal to a higher-level control unit (e.g., the FQC) indicating that the refueling shutoff valve is open. Conversely, if the refueling shutoff valve fails to open after the pressure refueling switch is turned on, and the fuel pressure sensor detects low pressure at the refueling shutoff valve outlet, the FQC will issue an alarm signal to the refueling control panel (RDCP), alerting the maintenance crew that the refueling shutoff valve is malfunctioning.

[0046] Figure 3 The figure is a schematic diagram of a fuel pressure measurement device according to one embodiment of the present invention. In one embodiment, the pressure sensor can integrate both electrical and mechanical interfaces to serve as a fuel pressure measurement device. Capacitive pressure sensors come in a variety of types, with single-capacitance and differential-capacitance types being common. The choice can be tailored to the project. Figure 3 View (a) in FIG. 1 shows a side view of a fuel pressure measuring device, and view (b) shows a top view of the fuel pressure measuring device.

[0047] As shown in the figure, the fuel pressure measuring device may include a mechanical interface 302 , one or more device-end fixing rings 303 and 304 , a fuse hole 305 , an electrical interface 306 , and a capacitive pressure sensor 310 .

[0048] The fuel pressure measurement device may have a hollow structure (e.g., a hollow tubular structure), and the capacitive pressure sensor 310 may be located on a wall surrounding the cavity, such as the inner wall of the tubular structure. The mechanical interface 302 of the fuel pressure measurement device (e.g., a threaded pipe interface) is configured to mate with the pressure supply line of the fuel pump / fuel shut-off valve, allowing fuel to enter the fuel pressure measurement device through the pressure supply line at its open end 301 and contact the capacitive pressure sensor 310, enabling the capacitive pressure sensor 310 to measure the fuel pressure.

[0049] The electrical interface 306 of the fuel pressure measuring device is the signal transmission port of the capacitive pressure sensor 310, which is connected to the FRDC through the fuel pressure measuring cable, and is used to receive the excitation signal applied to the capacitive pressure sensor 310 from the FRDC and transmit the fuel pressure signal detected by the capacitive pressure sensor 310 to the FRDC.

[0050] One or more device-side fixing rings 303 and 304 can clamp the main body of the fuel pressure measuring device. Ring 303 is connected to bracket 308 via a fastener, which is then secured to the structural ribs on the inner wall of the fuel tank. Similarly, device-side fixing ring 304 can be connected to the structural ribs inside the fuel tank via a bracket. This allows the fuel pressure measuring device to be secured to the inner wall of the fuel tank. Furthermore, the capacitive pressure sensor may include a fuse hole 305 for attaching a fuse.

[0051] Figure 4 FIG. 1 is a schematic assembly diagram of a fuel pressure measuring device according to an embodiment of the present invention.

[0052] The fuel pressure measuring device can be connected to one end of a pressure-supply line 404 via a threaded connector. The other end of the pressure-supply line 404 is located at the fuel pump outlet or on the refueling shut-off valve, transferring fuel from the fuel pump outlet or refueling shut-off valve to the fuel pressure measuring device. The fuel pressure measuring device can be secured to the structural ribs within the fuel tank using one or more retaining rings 304 and fasteners 405 (e.g., screws). The fuel pressure measurement cable 402 connects to an external FDRC via a fuel tank frame hole (e.g., the same frame hole used for the fuel quantity measurement cable), transmitting the fuel pressure signal to the FDRC.

[0053] The design of the fuel pressure measuring device's mechanical interfaces (e.g., threaded interfaces) and electrical interfaces (e.g., interfaces with fuel pressure measurement cable 402) should ensure that, when the fuel pressure measuring device is installed at an angle, the electrical interfaces are protected from water contamination. Furthermore, the mechanical interfaces are positioned at a "high point" to prevent the effects of water freezing or impurity accumulation on measurement. For example, the mechanical interface of the fuel pressure measuring device should be higher than the pressure lead line 404 to prevent the accumulation of water and impurities in the fuel at the pressure sensor's measurement port, thereby ensuring accurate pressure signal measurement.

[0054] The pressure sensor should be installed at a "low point" (i.e., the piping connection from the fuel pump / refueling shut-off valve outlet to the pressure sensor's measuring end) so that the pressure sensor's measuring end is at the highest point and the fuel pump / refueling shut-off valve outlet is at the lowest point. This ensures that water or impurities will not accumulate at the pressure sensor's measuring end, potentially affecting the pressure signal's accuracy and misleading pilots or ground crew. However, due to space constraints in the installation area, traditional mechanical pressure signal devices struggle to meet this requirement.

[0055] The aircraft capacitive fuel pressure indicating system proposed in the present invention uses a capacitive fuel sensor to measure the fuel pump outlet pressure and the refueling shut-off valve outlet pressure. By installing the capacitive fuel pressure sensor inside the fuel tank, the impact of rotor explosion can be avoided, and there is no need to open a frame hole in the structure to avoid oil leakage problems caused by insufficient sealing. When installing, the mechanical interface of the fuel pressure sensor is placed in a "high position" relative to the pressure-leading pipeline to avoid the influence of water in the fuel freezing or impurity accumulation in a cold environment on the pressure measurement, and at the same time ensure that the condensed water at the electrical interface can flow down the cable to avoid accumulation at the electrical interface and affect signal transmission. The fuel pressure measuring cable of the present invention can reuse the design of the fuel quantity measuring cable (for example, having a common cable type, shielding layer, and installation path), without the need to increase the research and development cost of cable ignition source protection in the fuel tank, and without the need to add frame holes and wiring channels on the fuel tank.

[0056] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which fall within the scope of protection of the present invention.

[0057] The various steps and modules of the methods and devices described above can be implemented in hardware, software, or a combination thereof. If implemented in hardware, the various illustrative steps, modules, and circuits described in conjunction with the present disclosure can be implemented or executed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic components, hardware components, or any combination thereof. A general-purpose processor can be a processor, a microprocessor, a controller, a microcontroller, or a state machine, etc. If implemented in software, the various illustrative steps and modules described in conjunction with the present disclosure can be stored or transmitted as one or more instructions or codes on a computer-readable medium. The software modules that implement the various operations of the present disclosure can reside in a storage medium, such as RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, removable disk, CD-ROM, cloud storage, etc. The storage medium can be coupled to a processor so that the processor can read and write information from / to the storage medium and execute corresponding program modules to implement the various steps of the present disclosure.

[0058] It should also be noted that these embodiments may be described as processes depicted as flow charts, flow diagrams, structure diagrams, or block diagrams. Although a flow chart may describe the operations as sequential processes, many of these operations can be performed in parallel or concurrently. In addition, the order of these operations can be rearranged.

[0059] The directions or positional relationships indicated by the directional words used in the description of this application, such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom", "inside, outside", etc., are generally based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of this application.

[0060] In addition, it should be noted that the use of serial words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0061] The disclosed methods, devices, and systems should not be limited in any way. On the contrary, the present disclosure covers all novel and non-obvious features and aspects of the various disclosed embodiments (alone and in various combinations and subcombinations with each other). The disclosed methods, devices, and systems are not limited to any specific aspect or feature or combination thereof, nor do any disclosed embodiments require any one or more specific advantages or solutions to specific or all technical problems.

Claims

1. An aircraft fuel pressure indicating system, characterized in that: include: A fuel pressure measuring device installed in a fuel tank of an aircraft, the fuel pressure measuring device comprising a mechanical interface, an electrical interface, and a capacitive pressure sensor; a pressure-conducting line, wherein a first end of the pressure-conducting line is located at the fuel pump outlet or on the refueling shut-off valve of the fuel tank, and a second end of the pressure-conducting line is connected to the mechanical interface of the fuel pressure measuring device, and is used to conduct fuel at the fuel pump outlet or the refueling shut-off valve to the fuel pressure measuring device; as well as A fuel pressure measurement cable is connected to the electrical interface of the fuel pressure measurement device and passes through the wall of the fuel tank, and is used to transmit the fuel pressure signal measured by the capacitive pressure sensor of the fuel pressure measurement device to a fuel signal processor located outside the fuel tank.

2. The aircraft fuel pressure indicating system according to claim 1, wherein: The mechanical interface includes a pipeline thread interface for adapting and connecting with the pressure-guiding pipeline.

3. The aircraft fuel pressure indicating system according to claim 1, wherein: The fuel pressure measuring device is mounted on the rib plate on the inner wall of the fuel tank through a bracket.

4. The aircraft fuel pressure indicating system according to claim 3, wherein: The fuel pressure measuring device is located above the pressure-conducting pipeline, and the electrical interface is higher than the mechanical interface and the pressure-conducting pipeline.

5. The aircraft fuel pressure indicating system according to claim 1, wherein: The fuel pressure measuring cable passes through the through-frame hole on the fuel tank and reaches the outside of the fuel tank.

6. The aircraft fuel pressure indicating system according to claim 5, wherein: The fuel pressure measuring cable and the fuel quantity measuring cable share the frame hole.

7. The aircraft fuel pressure indicating system according to claim 1, wherein: The fuel pressure measurement cable includes an excitation cable and a feedback cable for the capacitive pressure sensor.

8. The aircraft fuel pressure indicating system according to claim 1, wherein: The fuel signal processor includes a fuel remote data concentrator (FRDC), which converts the fuel pressure signal measured by the capacitive pressure sensor from an analog quantity to a digital quantity, and transmits the digital fuel pressure signal to a fuel computer (FQC). The fuel computer determines that the measured fuel pressure signal is a high-pressure / low-pressure discrete quantity.

9. The aircraft fuel pressure indicating system according to claim 8, wherein: The fuel computer sends the fuel pump high / low pressure discretes to the avionics system.

10. The aircraft fuel pressure indicating system according to claim 8, wherein: The fuel computer determines the high / low pressure discrete value of the refueling shut-off valve, and determines whether the fuel pressure of the refueling shut-off valve is normal based on the high / low pressure discrete value of the refueling shut-off valve. If the fuel pressure of the refueling shut-off valve is abnormal, the FQC generates a refueling alarm signal and provides the refueling alarm signal to a refueling control panel (RDCP).

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