UAV Fuel Supply System and Fuel Supply and Refueling Control Methods

Abstract

The present invention discloses an unmanned aerial vehicle fuel supply system and a fuel supply and refueling control method. In this system, a part of the fuel tank group is respectively connected to a pressurizing oil pump through a first pipeline; the pressurizing oil pump is connected to a pressurizing fuel tank through a third pipeline; another part of the fuel tank group is respectively connected to a refueling port through a second pipeline; the pressurizing fuel tank is connected to the engine through a fuel supply assembly; a four-way joint is arranged between the pressurizing oil pump and the first pipeline, and one end of the four-way joint is connected to the second pipeline through a fuel sequence control valve; the controller is respectively connected to the pressurizing oil pump, the fuel supply assembly, and the fuel sequence control valve; the controller is also connected to a flight control computer, and is used for receiving a pressurizing instruction and sending oil pressure and flow values. The present invention can ensure that within the altitude range of 0 to 20,000 m and under the service overload of 1 to 6 g, the fuel supply system can ensure a relative pressure of 25 kPa to 50 kPa, and ensure smooth fuel supply to the engine.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel supply equipment for unmanned aerial vehicles, and particularly relates to an unmanned aerial vehicle fuel supply system and a fuel supply and refueling control method. Background Art

[0002] The long-endurance unmanned aerial vehicle is a large-maneuver recoverable unmanned aerial vehicle system, which has the advantages of stealth, high speed (from high subsonic to supersonic), and large maneuver (stable 6G, instantaneous 9G). The layout feature of the long-endurance unmanned aerial vehicle is that the fuselage is slender and has a large fuel load. During takeoff and flight, especially during large-maneuver flight, the center of gravity is likely to change violently due to fuel sloshing. At the same time, the flight envelope flight altitude range is from 0 to 12,000 meters, and the pressure changes violently with the altitude. The engine fuel supply end requires constant-pressure fuel supply.

[0003] All the design schemes adopted by the prior art for maintaining pressure fuel supply are to use engine bleed air for pressurization. Therefore, turbojet engines used for unmanned aerial vehicles are all designed with engine bleed air ports, that is, a small amount of high-pressure air is led out from behind the engine compressor and input into the fuel tank compartment to pressurize the inside or outside of the fuel tank. However, the fuel tank itself is a rubber flexible fuel tank. Whether the pressure (pressure) is applied outside or inside the fuel tank, it must be borne by the hard shell load-bearing structure of the aircraft body. Since the fuel consumption of turbojet engines is relatively large and the fuel load on the aircraft is very large, generally accounting for 25% to 40% of the total takeoff weight of the aircraft, and the percentage of the aircraft body volume is also quite the same. In terms of pressure, a pressure of 50 Kpa means that a force of 0.5 kg acts on each square centimeter. For an aircraft structure with a fuel tank area of 1 square meter, the tensile force to be borne is 5,000 kg.

[0004] Currently, from small unmanned aerial vehicles to large unmanned aerial vehicles, composite material structures are basically adopted. (Whether it is fiberglass, carbon fiber or other composite materials), most of the connections between the body structures are glued, especially the connections between the aircraft fuselage skin and the fuselage frame and beams. The peel strength of the glued structure is very low. The pressure input into the fuel tank compartment is exactly the extremely destructive tensile force, that is, the peel force. Once peeling occurs between the structural connections, the structural strength of the aircraft will drop sharply, and in severe cases, the aircraft will disintegrate. In addition to peel damage, this pressure will also cause the relevant aircraft outer skin panels to bulge and deform, destroying the aircraft aerodynamic shape, increasing the aircraft drag, and reducing the flight performance of the aircraft. In order to ensure that the aircraft structure can withstand this inflation pressure, this load must be considered in the structural design. On top of the structure originally required for the aircraft to bear the aerodynamic load, the structural strength is increased, that is, the thickness of the structural panels is increased, the glued surface is increased, thereby greatly increasing the aircraft structural weight, materials, as well as the difficulty and manufacturing cost of the relevant manufacturing processes.

[0005] In addition, for pressurization, the airframe structure must also be sealed. This seal should withstand the flight aerodynamic loads while also being able to withstand the inflation pressure during inflation, and ensure that the deformation (bending and torsion) of the airframe under various loading conditions does not cause air leakage in the sealed cabin. Once there is air leakage, it is impossible to supply fuel to the engine, resulting in a serious accident of an in-flight engine shutdown; it is also very difficult to perform secondary sealing during repair, which requires high requirements for the airframe structure design and manufacturing process, and also greatly increases the cost. Summary of the Invention

[0006] In view of this, the main object of the present invention is to provide an unmanned aerial vehicle fuel supply system and a fuel supply and refueling control method.

[0007] To achieve the above object, the technical solution of the present invention is realized as follows:

[0008] An embodiment of the present invention provides an unmanned aerial vehicle fuel supply system, which includes a fuel tank group, a first pipeline, a second pipeline, a fuel filling port, a pressurizing oil pump, a pressurizing fuel tank, a controller, and a fuel supply assembly;

[0009] A part of the fuel tank group is respectively connected to the pressurizing oil pump through the first pipeline;

[0010] The pressurizing oil pump is connected to the pressurizing fuel tank through a third pipeline;

[0011] Another part of the fuel tank group is respectively connected to the fuel filling port through the second pipeline;

[0012] The pressurizing fuel tank is connected to the engine through the fuel supply assembly;

[0013] A four-way joint is arranged between the pressurizing oil pump and the first pipeline, and one end of the four-way joint is connected to the second pipeline through a fuel sequence control valve;

[0014] The controller is respectively connected to the pressurizing oil pump, the fuel supply assembly, and the fuel sequence control valve; the controller is also connected to the flight control computer, receives a pressurizing instruction, and sends oil pressure and flow rate values.

[0015] In the above solution, a ball valve is further included, and the second pipeline is also connected to the third pipeline through the ball valve for use during ground air extraction or refueling.

[0016] In the above solution, a pressure monitoring assembly is further included, and the other end of the four-way joint is connected to the pressurizing fuel tank through the pressure monitoring assembly.

[0017] In the above scheme, the pressure monitoring component includes a pressure reducing valve and a pressure detector. The pressure reducing valve is arranged on the pipeline between one end of the four-way joint and the pressurized oil tank to form a pressure relief circuit. The pressure detector is arranged on the pressure reducing valve, or on the pipeline between the pressure reducing valve and the pressurized oil tank, or on other pipelines directly connected to the pressurized oil tank. The controller is connected to the pressure detector.

[0018] In the above scheme, the oil tank group includes a front oil tank and a rear oil tank, and the front oil tank and the rear oil tank are both composed of several groups of vacuum split soft oil tanks. The several groups of vacuum split soft oil tanks of the front oil tank are respectively connected to the first pipeline, and the several groups of vacuum split soft oil tanks of the rear oil tank are respectively connected to the second pipeline.

[0019] In the above scheme, the oil supply assembly includes a fourth pipeline, an oil filter, a flow meter, a main oil circuit solenoid valve, and an engine main oil pump. The pressurized oil tank is connected to the engine through the oil supply assembly. The fourth pipeline is sequentially provided with a flow meter, a main oil circuit solenoid valve, and an engine main oil pump along the oil supply direction. The oil filter is provided between the flow meter and the pressurized oil tank, or between the flow meter and the main oil circuit solenoid valve. The flow meter is connected to the controller, and the main oil circuit solenoid valve and the engine main oil pump are respectively connected to the engine controller.

[0020] An embodiment of the present invention also provides a fuel supply control method for a fuel supply system of a UAV, the method being: during the front stage of flight of the UAV, the ball valve is in a closed state by default, the controller drives the pressurized oil pump, closes the fuel sequence control valve, and the front oil tank of the oil tank group supplies oil to the pressurized oil tank through a first pipeline, and the fuel in the pressurized oil tank is transported to the engine through the oil supply assembly.

[0021] In the above scheme, the method also includes: during the later stage of flight of the UAV, the ball valve is in a closed state by default, the controller drives the pressurized oil pump, opens the fuel sequence control valve, and the rear tank of the fuel tank group supplies oil to the pressurized oil tank through the second pipeline and the pressurized oil pump, and the fuel in the pressurized oil tank is transported to the engine through the fuel supply assembly.

[0022] In the above scheme, the pressure detector of the pressure monitoring assembly collects the pressure in the pressurized oil tank, and the controller determines whether to increase or decrease the pressure in the pressurized oil tank according to the pressure condition in the pressurized oil tank.

[0023] The embodiment of the present invention also provides a refueling control method for an unmanned aerial vehicle (UAV) fuel supply system. The method is as follows: during the air extraction and refueling process of the UAV, manually open the ball valve, the controller opens the fuel sequence control valve, and the refueling equipment performs air extraction and refueling on the rear fuel tank of the fuel tank group through the refueling port and the second pipeline, performs air extraction and refueling on the front fuel tank of the fuel tank group through the front section of the second pipeline, the fuel sequence control valve and the four-way joint to the first pipeline, and performs air extraction and refueling on the pressurized fuel tank through the refueling port and the ball valve until all the air in the fuel tanks is exhausted and the fuel tanks are filled up.

[0024] Compared with the prior art, the present invention can ensure that within the altitude range of 0 - 20000 m and under the operating overload of 1 - 6 g, the fuel supply system can ensure a relative pressure of 25 kPa - 50 kPa (it can also be other pressure ranges), ensuring smooth fuel supply to the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings described herein are used to disclose a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0026] Figure 1 is a schematic structural diagram of a UAV fuel supply system provided by an embodiment of the present invention;

[0027] Figure 2 is a flowchart of a fuel supply control method for a UAV fuel supply system provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] An embodiment of the present invention provides a UAV fuel supply system, as Figure 1 shown. The system includes a fuel tank group 1, a first pipeline 2, a second pipeline 3, a refueling port 4, a pressurizing oil pump 6, a pressurized fuel tank 7, a controller 8, and a fuel supply assembly 9;

[0030] A part of the fuel tank group 1 is respectively connected to the pressurizing oil pump 6 through the first pipeline 2;

[0031] The pressurizing oil pump 6 is connected to the pressurized fuel tank 7 through a third pipeline 61;

[0032] Another part of the fuel tank group 1 is respectively connected to the refueling port 4 through the second pipeline 3;

[0033] The pressurized fuel tank 7 is connected to the engine through the fuel supply assembly 9;

[0034] A four-way joint 11 is arranged between the pressurized fuel pump 6 and the first pipeline 2, and one end of the four-way joint 11 is connected to the second pipeline 3 through the fuel sequence control valve 12;

[0035] The controller 8 is respectively connected to the pressurized fuel pump 6, the fuel supply assembly 9, and the fuel sequence control valve 12; the controller 8 is also connected to the flight control computer to receive a pressurization instruction and send oil pressure and flow rate values.

[0036] The controller 8 is connected to the pressurized fuel pump 6 to adjust its working state, the controller 8 is connected to the fuel supply assembly 9 to collect the fuel consumption and control the opening timing of the fuel sequence control valve 12 according to the fuel consumption, the controller 8 is connected to the pressure detection assembly 10 to collect the pressure in the pressurized fuel tank, and use this pressure to control the rotation speed of the pressurized fuel pump, and the controller 8 is connected to the fuel sequence control valve 12 to control its opening and closing.

[0037] Furthermore, a pressure monitoring assembly 10 is further included. A four-way joint 11 is arranged between the pressurized fuel pump 6 and the first pipeline 2, and one end of the four-way joint 11 is connected to the pressurized fuel tank 7 through the pressure monitoring assembly 10.

[0038] The pressure monitoring assembly 10 includes a pressure reducing valve 1001 and a pressure detector 1002. The pressure reducing valve 1001 is arranged on the pipeline between one end of the four-way joint 11 and the pressurized fuel tank 7 to form a pressure relief circuit. The pressure detector 1002 is arranged on the pressure reducing valve 1001, or on the pipeline between the pressure reducing valve 1001 and the pressurized fuel tank 7, or on other pipelines directly connected to the pressurized fuel tank. The controller 8 is connected to the pressure detector 1002.

[0039] The pressure detector 1002 uses a pressure sensor, that is, a pressure transmitter, to detect the pressure in the pressurized fuel tank 7; it can be installed on the pressure reducing valve 1001, or in the pipeline between the pressure reducing valve 1001 and the pressurized fuel tank 7, or in the pipeline between the pressurized fuel pump 6 and the pressurized fuel tank 7, and in the pipeline between the oil filter 91 and the pressurized fuel tank 7.

[0040] The pressure reducing valve 1001 is a mechanical pressure reducing valve, and the opening pressure can be adjusted as needed. When the pressure in the pressurized fuel tank 7 exceeds the design value, it automatically opens to relieve pressure.

[0041] When the pressure in the pressurized fuel tank 7 exceeds the design value, the pressure reducing valve 1001 is immediately conducted, so that the fuel in the pressurized fuel tank 7 can flow back to the pipeline at the inlet of the pressurized fuel pump 6.

[0042] The fuel tank group 1 includes a front fuel tank 101 and a rear fuel tank 102. Both the front fuel tank 101 and the rear fuel tank 102 are composed of several groups of vacuum split soft fuel tanks. The several groups of vacuum split soft fuel tanks of the front fuel tank 101 are respectively connected to the first pipeline 2, and the several groups of vacuum split soft fuel tanks of the rear fuel tank 102 are respectively connected to the second pipeline 3.

[0043] The front fuel tank 101 and the rear fuel tank 102 adopt vacuum split soft fuel tanks, which can comprehensively suppress fuel sloshing during flight and suppress the influence of fuel sloshing on the flight center of gravity of the UAV.

[0044] Manage the front fuel tank 101 and the rear fuel tank 102 according to the fuel sequence to reduce the change of the whole aircraft's center of gravity caused by fuel consumption.

[0045] The fuel supply component 9 includes a fourth pipeline 91, an oil filter 92, a flow meter 93, a main oil pipeline solenoid valve 94, and an engine main oil pump 95. The pressurized fuel tank 7 is connected to the engine through the fuel supply component 9. The fourth pipeline 91 is sequentially provided with a flow meter 93, a main oil pipeline solenoid valve 94, and an engine main oil pump 95 along the fuel supply direction. The oil filter 92 is arranged between the flow meter 93 and the pressurized fuel tank 7, or between the flow meter 93 and the main oil pipeline solenoid valve 94. The flow meter 93 is connected to the controller 8, and the main oil pipeline solenoid valve 94 and the engine main oil pump 95 are respectively connected to the engine controller.

[0046] According to the requirements of the engine for the fuel supply system, when the engine is not working, fuel cannot be supplied to the engine. When the engine fuel pump 95 is not working, it does not have the cut-off ability. Once a large amount of fuel flows into the non-working engine, the engine cannot be started. Therefore, a main oil pipeline solenoid valve 94 is designed at the end of the oil source system. The fuel supply oil pipeline is opened when the engine starts and closed until the engine stops working.

[0047] The flow meter 93 measures the outflowing oil volume, provides the total fuel consumption, and provides a basis for the opening timing of the fuel sequence control valve 12.

[0048] As Figure 2 shown, the embodiment of the present invention also provides a fuel supply control method for a UAV fuel supply system. The method is as follows: During the front-stage flight of the UAV, the ball valve 5 is default in the closed state. The controller 8 drives the pressurized oil pump 6, closes the fuel sequence control valve 12. The front fuel tank 101 of the fuel tank group 1 supplies fuel to the pressurized fuel tank 7 through the first pipeline 2, and the fuel in the pressurized fuel tank 7 is transported to the engine through the fuel supply component 9.

[0049] During the later stage of the UAV flight, the ball valve 5 is defaultly in the closed state. The controller 8 drives the pressurizing oil pump 6 to open the fuel sequence control valve 12. The rear fuel tank 102 of the fuel tank group 1 supplies fuel to the pressurizing fuel tank 7 through the second pipeline 3 and the pressurizing oil pump 6. The fuel in the pressurizing fuel tank 7 is delivered to the engine through the fuel supply assembly 9.

[0050] The pressure detector 1002 of the pressure monitoring assembly 10 collects the pressure in the pressurizing fuel tank 7. The controller 8 determines whether to increase or decrease the pressure in the pressurizing fuel tank 7 according to the pressure condition in the pressurizing fuel tank 7.

[0051] Increasing or decreasing the pressure in the pressurizing fuel tank 7 is achieved by increasing or decreasing the flow rate of the pressurizing oil pump 6.

[0052] Once the pressure in the pressurizing fuel tank 7 exceeds the design value, the pressure reducing valve 1001 automatically opens for pressure relief.

[0053] The design value of the embodiment of the present invention is 45 - 50 Kpa, and it can be designed as other pressure ranges as required.

[0054] Since the center of gravity of the aircraft moves forward seriously after the take-off booster rocket of the high-speed target drops off, and the center of gravity of the aircraft will also move forward after the cruise afterburner rocket works. Therefore, after the aircraft takes off, the fuel before the center of gravity is used first to move the center of gravity of the aircraft backward to offset the adverse effects caused by the booster rocket.

[0055] The embodiment of the present invention also provides a fuel supply control method for the UAV fuel supply system. The method is as follows: during the air extraction and refueling process of the UAV, the ball valve 5 is manually opened, and the controller 8 opens the fuel sequence control valve 12. The refueling equipment conducts air extraction and refueling for the rear fuel tank 102 of the fuel tank group 1 through the fuel filling port 4 and the second pipeline 3, conducts air extraction and refueling for the front fuel tank 101 of the fuel tank group 1 through the front section of the fuel filling port 4 and the second pipeline 3 via the fuel sequence control valve 12 and the four-way joint 11 to the first pipeline 2, and conducts air extraction and refueling for the pressurizing fuel tank 7 through the fuel filling port 4 and the ball valve 5 until all the air in the fuel tanks is exhausted and the fuel tanks are full.

[0056] In the attached drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the attached drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the attached drawings are only for illustrative purposes and cannot be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0057] It should be noted that in this document, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, article or device comprising such element.

[0058] The above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. An unmanned aerial vehicle fuel supply system, characterized in that, The system includes a fuel tank group, a first pipeline, a second pipeline, a fuel filling port, a pressurizing oil pump, a pressurizing fuel tank, a controller, and a fuel supply assembly; A part of the fuel tank group is respectively connected to the pressurizing oil pump through the first pipeline; The pressurizing oil pump is connected to the pressurizing fuel tank through a third pipeline; Another part of the fuel tank group is respectively connected to the fuel filling port through the second pipeline; The pressurizing fuel tank is connected to the engine through the fuel supply assembly; A four-way joint is arranged between the pressurizing oil pump and the first pipeline, and one end of the four-way joint is connected to the second pipeline through a fuel sequence control valve; The controller is respectively connected to the pressurizing oil pump, the fuel supply assembly, and the fuel sequence control valve; the controller is also connected to the flight control computer for receiving a pressurizing instruction and sending oil pressure and flow rate values; the controller is connected to the fuel supply assembly for collecting the fuel consumption and controlling the opening timing of the fuel sequence control valve according to the fuel consumption; the controller is connected to the fuel sequence control valve for controlling its opening and closing; The fuel tank group includes a front fuel tank and a rear fuel tank. Both the front fuel tank and the rear fuel tank are composed of several groups of vacuum split soft fuel tanks. The several groups of vacuum split soft fuel tanks of the front fuel tank are respectively connected to the first pipeline, and the several groups of vacuum split soft fuel tanks of the rear fuel tank are respectively connected to the second pipeline.

2. The fuel supply system for the unmanned aerial vehicle according to claim 1, wherein It also includes a ball valve. The second pipeline is also connected to the third pipeline through the ball valve for use during ground air extraction or fuel filling.

3. The drone fuel supply system according to claim 2, characterized in that, It also includes a pressure monitoring assembly. The other end of the four-way joint is connected to the pressurizing fuel tank through the pressure monitoring assembly.

4. The drone fuel supply system according to claim 3, wherein, The pressure monitoring assembly includes a pressure reducing valve and a pressure detector. The pressure reducing valve is arranged on the pipeline between one end of the four-way joint and the pressurizing fuel tank to form a pressure relief circuit. The pressure detector is arranged on the pressure reducing valve, or on the pipeline between the pressure reducing valve and the pressurizing fuel tank, or on other pipelines directly connected to the pressurizing fuel tank. The controller is connected to the pressure detector.

5. The drone fuel supply system according to claim 4, characterized in that, The fuel supply assembly includes a fourth pipeline, an oil filter, a flow meter, a main oil pipeline solenoid valve, and an engine main oil pump. The pressurizing fuel tank is connected to the engine through the fuel supply assembly. The fourth pipeline is sequentially provided with a flow meter, a main oil pipeline solenoid valve, and an engine main oil pump along the fuel supply direction. The oil filter is arranged between the flow meter and the pressurizing fuel tank, or between the flow meter and the main oil pipeline solenoid valve. The flow meter is connected to the controller. The main oil pipeline solenoid valve and the engine main oil pump are respectively connected to the engine controller.

6. A fuel supply control method for a fuel supply system of an unmanned aerial vehicle according to any one of claims 1-5, characterized in that, The method is as follows: During the front-stage flight of the unmanned aerial vehicle, the ball valve is default in the closed state. The controller drives the pressurizing oil pump, closes the fuel sequence control valve. The front fuel tank of the fuel tank group supplies fuel into the pressurizing fuel tank through the first pipeline. The fuel in the pressurizing fuel tank is transported to the engine through the fuel supply assembly; The front fuel tank is composed of several groups of vacuum split soft fuel tanks.

7. The fuel supply control method for the UAV fuel supply system according to claim 6, characterized in that The method also includes: During the rear-stage flight of the unmanned aerial vehicle, the ball valve is default in the closed state. The controller drives the pressurizing oil pump, opens the fuel sequence control valve. The rear fuel tank of the fuel tank group supplies fuel into the pressurizing fuel tank through the second pipeline and the pressurizing oil pump. The fuel in the pressurizing fuel tank is transported to the engine through the fuel supply assembly.

8. The fuel supply control method for the unmanned aerial vehicle fuel supply system according to claim 7, characterized in that, The pressure detector of the pressure monitoring component collects the pressure in the pressurized fuel tank, and the controller determines whether to increase or decrease the pressure in the pressurized fuel tank according to the pressure condition in the pressurized fuel tank.

9. A refueling control method for an unmanned aerial vehicle fuel supply system according to any one of claims 1-5, characterized in that, The method is as follows: during the air extraction and fuel filling process of the UAV, manually open the ball valve, the controller opens the fuel sequence control valve, and the fuel filling device performs air extraction and fuel filling to the rear fuel tank of the fuel tank group through the fuel filling port and the second pipeline, performs air extraction and fuel filling to the front fuel tank of the fuel tank group through the front section of the second pipeline via the fuel sequence control valve and the four-way joint to the first pipeline, and performs air extraction and fuel filling to the pressurized fuel tank through the fuel filling port and the ball valve until all the air in the fuel tanks is exhausted and the fuel tanks are full.

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