A fuel control device and an aircraft

Abstract

This utility model provides a fuel control device, comprising: a controller and a fuel collection tank. A fuel extraction unit is provided at one end of the fuel collection tank, and a buffer is provided at the other end. The controller is electrically connected to the fuel extraction unit. The fuel extraction unit includes a first fuel pump and a second fuel pump. A first flow meter is connected to the first fuel pump, and the first fuel pump is connected to the fuel collection tank via the first flow meter. A second flow meter is connected to the second fuel pump, and the second fuel pump is connected to the fuel collection tank via the second flow meter. The rotational speeds of the first and second fuel pumps are adjusted by the cumulative flow difference between the first and second flow meters to achieve fuel center of gravity balance. Compared with the prior art, this fuel control device can not only balance the center of gravity of the aircraft but also ensure fuel pressure stability.

Description

Technical Field

[0001] This utility model relates to the field of small and medium-sized aircraft technology, and in particular to a fuel control device and an aircraft. Background Technology

[0002] In aircraft design, aircraft typically have multiple fuel tanks distributed across the fuselage and wings. A fuel collection tank is required before the engine fuel inlet to collect fuel from these multiple tanks and feed it directly into the engine. Because flight conditions change in real time, such as high and low altitude cruise, climb, dive, acceleration / deceleration, and roll, the fuel will slosh violently during these processes. If left uncontrolled, this can lead to problems such as loss of center of gravity, fuel foaming, unstable fuel pressure, and engine fuel starvation. To ensure normal flight, the aircraft fuel system must have functions such as center of gravity regulation, stable fuel flow, stable fuel pressure, and air bubble removal. Traditional aircraft fuel systems are mostly designed for large aircraft with ample onboard space, facilitating the installation of complex fuel lines and control systems.

[0003] Most existing small and medium-sized drones use simplified model aircraft fuel systems or adopt complex fuel systems from large aircraft. The former has a simple structure but small fuel capacity, cannot fly at high altitudes, is not easy to stabilize and boost pressure, and has an uncontrollable center of gravity; the latter is large in size and expensive, making it difficult to apply to small and medium-sized drones with a maximum takeoff weight of ≤500kg and a fuel ratio of ≥30%.

[0004] Therefore, existing problems need to be improved in order to solve the above-mentioned issues. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model provides a fuel control device, an aircraft, and a control method for the fuel control device. The fuel control device is suitable for small and medium-sized aircraft, has a relatively low cost, and can not only balance the center of gravity of the aircraft but also ensure the stability of the oil pressure.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0007] A fuel control device includes: a controller and a fuel collection tank, wherein a fuel extraction unit is provided at one end of the fuel collection tank and a buffer is provided at the other end of the fuel collection tank, and the controller is electrically connected to the fuel extraction unit.

[0008] The fuel extraction unit includes a first fuel pump and a second fuel pump. A first flow meter is connected to the first fuel pump, and the first fuel pump is connected to the fuel collection tank through the first flow meter. A second flow meter is connected to the second fuel pump, and the second fuel pump is connected to the fuel collection tank through the second flow meter.

[0009] By adjusting the cumulative flow difference between the first flow meter and the second flow meter, the rotational speeds of the first fuel pump and the second fuel pump are adjusted to achieve fuel center of gravity balance.

[0010] Preferably, the system further includes a first filter and a second filter, which are respectively connected to the first fuel pump and the second fuel pump.

[0011] Preferably, the buffer is provided with an exhaust valve.

[0012] Preferably, the oil collection tank includes a tank body, a front cover at the front end of the tank body, and a rear cover at the rear end of the tank body;

[0013] The front cover is equipped with a pressure sensor and two one-way valves, and the first flow meter and the second flow meter are respectively connected to the one-way valves;

[0014] The rear cover is provided with an oil outlet located below the surface of the rear cover. A counterweight is provided inside the box. The counterweight has a through-hole structure and is connected to the oil outlet through a flexible hose so that the counterweight is located inside the bottom of the box.

[0015] The front cover and the rear cover are fixed to the front and rear ends of the box body by multiple connecting rods respectively.

[0016] Preferably, the front cover and the rear cover are each provided with a sealing groove, the box body is embedded in the sealing groove, and sealant is provided at the joint to achieve sealing.

[0017] Preferably, there are four connecting rods, each of which is a hollow metal rod with internal threads, and the connecting rods are connected to the front cover and the rear cover by bolts.

[0018] Preferably, the first filter and the second filter are metal mesh filters, the first flow meter and the second flow meter are gear-type volumetric flow meters, and the first fuel pump and the second fuel pump are gear pumps or centrifugal pumps.

[0019] An aircraft includes: an airframe, wherein the fuel control device is disposed within the airframe.

[0020] The beneficial effects of this utility model are: it is suitable for small and medium-sized UAVs, has a relatively low cost, and can not only balance the center of gravity of the aircraft, but also ensure the stability of the oil pressure. Attached Figure Description

[0021] The above and other objects, features, and advantages of this invention will become clearer through a more detailed description of the preferred embodiments shown in the accompanying drawings. The same reference numerals indicate the same parts throughout the drawings, and the drawings are not intentionally drawn to scale with actual dimensions; the focus is on illustrating the gist of this invention.

[0022] Figure 1 This is a schematic diagram of the aircraft's structure.

[0023] Figure 2 This is a schematic diagram of the fuel control device.

[0024] Figure 3 This is a schematic diagram of the exploded structure of the oil collection tank;

[0025] Figure 4 This is a schematic diagram of the internal structure of the oil collection tank;

[0026] Figure 5 A schematic diagram of the internal structure of the oil collection tank without a counterweight;

[0027] Figure 6 This is a schematic diagram of the connection principle of this application.

[0028] Reference numerals: 1. Engine body; 2. Fuel control device; 3. Floor beam; 21. Controller; 22. Fuel tank; 23. Fuel extraction unit; 24. Buffer; 221. Housing; 222. Front cover; 223. Rear cover; 224. Pressure sensor; 225. Check valve; 226. Counterweight; 227. Connecting rod; 231. First fuel pump; 232. Second fuel pump; 241. Exhaust valve; 2221. Sealing groove; 2261. Hoses; 2311. First filter; 2312. First flow meter; 2321. Second filter; 2322. Second flow meter. Detailed Implementation

[0029] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be given below with reference to the accompanying drawings.

[0030] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to and integrated with the other component, or there may be an intervening component present. The terms "mounted," "one end," "the other end," and similar expressions used in this document are for illustrative purposes only.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] like Figure 1 As shown, an aircraft includes: a fuselage 1, a fuel control device 2 inside the fuselage 1, and the fuel control device 2 being connected to the fuselage 1 via a floor beam 3.

[0033] like Figure 2 As shown, the fuel control device 2 includes a controller 21 and a fuel tank 22. A fuel extraction unit 23 is located at one end of the fuel tank 22, and a buffer 24 is located at the other end. The controller 21 is electrically connected to the fuel extraction unit 23. An exhaust valve 241 is installed on the buffer 24. The fuel tank 22 is connected to the buffer 24. When the fuel pressure changes, the buffer gas inside the buffer 24 is preferentially compressed or expanded, making the fuel pressure change smoother and preventing sudden changes in fuel pressure from causing increased system oscillations. The buffer 24 is a container with no internal structural design; it is mainly used to store gas. The exhaust valve 241 is only used for initial gas pressure adjustment and does not exhaust gas during operation. This fuel control device 2 has a simple structure and relatively low cost, making it suitable for small and medium-sized aircraft.

[0034] The fuel extraction unit 23 includes a first fuel pump 231 and a second fuel pump 232. A first flow meter 2312 and a first filter 2311 are respectively connected to the first fuel pump 231. The first fuel pump 231 is connected to the fuel collection tank 22 through the first flow meter 2312. A second flow meter 2322 and a second filter 2321 are respectively connected to the second fuel pump 232. The second fuel pump 232 is connected to the fuel collection tank 22 through the second flow meter 2322. By providing the first filter 2311 and the second filter 2321, impurities in the fuel can be effectively filtered, ensuring the quality of the absorbed fuel. Furthermore, the cumulative flow difference between the first flow meter 2312 and the second flow meter 2322 is used to adjust the rotational speed of the first fuel pump 231 and the second fuel pump 232, achieving fuel center of gravity balance. In this application, the first fuel pump 231 is used to regulate fuel pressure and can quickly correct fuel pressure deviations, while the second fuel pump 232 is used to regulate flow rate and can gradually reduce the cumulative flow difference. The two fuel pumps have different control strategies: the right side uses pressure control and the left side uses flow control. The two control paths are nested to simultaneously control fuel pressure and flow while avoiding mutual interference. At the same time, this invention adds a buffer 24 to the oil circuit to ensure stable oil pressure and ensure the stability of engine fuel supply.

[0035] like Figure 3-5As shown, the oil collection tank 22 includes a tank body 221. A front cover 222 is provided at the front end of the tank body 221, and a rear cover 223 is provided at the rear end of the tank body 221. A pressure sensor 224 and two one-way valves 225 are provided on the front cover 222. A first flow meter 2312 and a second flow meter 2322 are respectively connected to the one-way valves 225. The pressure sensor 224 is used to detect the oil pressure in the tank body 221.

[0036] The rear cover 223 has an oil outlet located below the surface of the rear cover 223. A counterweight 226 is installed inside the housing 221. The counterweight 226 is a hollow, through-hole structure and is connected to the oil outlet via a flexible hose 2261, ensuring that the counterweight 226 is located at the bottom of the housing 221. When the aircraft is in level flight, the flexible hose 2261 naturally extends to the lowest point of the fuel tank 22. When the aircraft performs maneuvers, such as inverted flight (the dotted lines represent the aircraft in inverted flight), the weight of the counterweight 226 causes the flexible hose 2261 to bend and droop down to the lowest point inside the housing 221, ensuring that the flexible hose 2261 can draw fuel. Furthermore, due to the counterweight 226, gasoline air bubbles inside the housing 221 will be located at the top of the housing 221, while the fuel extraction point remains at the bottom of the housing 221, preventing the extracted fuel from containing air bubbles. This effectively improves the quality of the extracted fuel by eliminating air bubbles.

[0037] The front cover 222 and the rear cover 223 are respectively fixed to the front and rear ends of the housing 221 by multiple connecting rods 227. Specifically, the connecting rods 227 are hollow metal rods with internal threads. The connecting rods 227 are connected to the front and rear covers by bolts, which pass through the threaded holes of the front and rear covers and are screwed into the threaded holes of the connecting rods 227. In this application, there are four connecting rods 227, which can effectively apply preload to ensure a seal.

[0038] The front cover 222 and the rear cover 223 are each provided with a sealing groove 2221. The housing 221 is embedded in the sealing groove 2221, and sealant is provided at the joint to achieve a seal. The sealant sealing method used in this application is different from the sealant sealing method of rubber elastic elements. This is because elastic sealing elements are prone to material creep and oil leakage when oil pressure changes or when the ambient temperature changes drastically. However, the sealant can adhere tightly to the contact surface, resulting in higher reliability.

[0039] The first filter 2311 and the second filter 2321 are metal mesh filters, which offer advantages such as high-efficiency filtration, durability, and fire resistance, making them highly suitable for aircraft. The first flow meter 2312 and the second flow meter 2322 are gear-type volumetric flow meters, offering high measurement accuracy and strong anti-interference capabilities, resulting in more precise measurements and reduced errors. The first fuel pump 231 and the second fuel pump 232 are gear pumps or centrifugal pumps, both equipped with their own motors and electrically driven.

[0040] like Figure 6 As shown, a control method based on a fuel control device 2 includes the following steps:

[0041] S1. Set a first threshold Ptarget and a second threshold, and obtain a first flow velocity value ql, a second flow velocity value qr, a first cumulative flow value Ql, a second cumulative flow value Qr, and a real-time oil pressure value Pi through a fixed acquisition period; In this application, the first threshold Ptarget is the target oil pressure value, the second threshold is the cumulative flow value, the first threshold Ptarget is ±10kPa, the second threshold is ±100g, and the fixed acquisition period is 100ms.

[0042] S2. Calculate the oil pressure deviation value e_p and the cumulative flow deviation value e_q, determine the relationship between the oil pressure deviation value e_p and the first threshold Ptarget, and determine the relationship between the cumulative flow deviation value e_q and the second threshold.

[0043] S3. If the oil pressure deviation value e_p > the first threshold Ptarget, then the speed of the first fuel pump 231 is independently adjusted by the first PID control method to form the first target flow rate ql_target.

[0044] If the oil pressure deviation value e_p ≤ the first threshold Ptarget, then adjust the first fuel pump 231 or keep the current speed of the first fuel pump 231 at the first target flow rate;

[0045] If the cumulative flow deviation value e_q > the second threshold, the speed of the second fuel pump 232 is independently adjusted by the second PID control method to form the second target flow rate qr_target;

[0046] If the cumulative flow deviation value e_q ≤ the second threshold, then adjust the second fuel pump 232 or keep the current speed of the second fuel pump 232 at the second target flow rate qr_target;

[0047] The first PID control method and the second PID control method are independent of each other and have no cross-coupling.

[0048] S4. Convert the first target flow velocity ql_target and the second target flow velocity qr_target into fuel pump control signals and output them to the first fuel pump 231 and the second fuel pump 232 respectively.

[0049] S5. In the next fixed acquisition cycle, repeat steps S1-S4 until the oil pressure deviation value e_p and the cumulative flow deviation value e_q simultaneously meet the requirements.

[0050] In S3, when the oil pressure deviation value e_p is greater than the first threshold Ptarget, the fluctuation is first absorbed by the buffer 24, and then adjusted by the first PID control method.

[0051] The first PID control method includes: taking the oil pressure deviation value e_p as input and the flow rate adjustment amount Δql of the first fuel pump 231 as output; if the oil pressure deviation value e_p > the first threshold Ptarget, outputting a positive flow rate adjustment amount Δql of the first fuel pump 231, increasing the speed of the first fuel pump 231, increasing the first flow rate value ql_target, increasing the total flow rate, and raising the oil pressure in the oil tank 22; if the oil pressure deviation value e_p < the first threshold Ptarget, outputting a negative flow rate adjustment amount Δql of the first fuel pump 231, decreasing the speed of the first fuel pump 231, decreasing the first flow rate value ql_target, decreasing the total flow rate, and lowering the oil pressure in the oil tank 22; if the absolute value of the oil pressure deviation value e_p ≤ the first threshold Ptarget, the output flow rate adjustment amount Δql of the first fuel pump 231 is equal to zero, and the first fuel pump 231 maintains the current flow rate.

[0052] Oil pressure PID parameters: Based on the actual control effect, adjust and determine the proportional coefficient Kp_p, integral time Ti_p, and derivative time Td_p, prioritizing oil pressure stability and avoiding overshoot.

[0053] The second PID control method includes taking the cumulative flow deviation value e_q as input and the flow rate adjustment amount Δqr of the second fuel pump 232 as output. If the cumulative flow deviation value e_q > the second threshold, a positive adjustment amount Δqr of the second fuel pump 232 is output, increasing the speed of the second fuel pump 232, increasing the second flow rate value qr_target, accelerating the growth rate of the second cumulative flow value Qr, and narrowing the gap between the first cumulative flow value Ql and the second cumulative flow value Qr. If the cumulative flow deviation value e_q < the second threshold, a negative adjustment amount Δqr of the second fuel pump 232 is output, decreasing the speed of the second fuel pump 232, decreasing the second flow rate value qr_target, slowing down the growth rate of the second cumulative flow value Qr, and waiting for the first cumulative flow value Ql to catch up. If the absolute value of the cumulative flow deviation value e_q ≤ the second threshold, the output adjustment amount Δqr of the second fuel pump 232 is equal to zero, and the second fuel pump 232 maintains the current flow rate.

[0054] Flow rate PID parameters: The proportional coefficient Kp_q, integral time Ti_q, and derivative time Td_q need to be adjusted and determined. Priority should be given to ensuring flow rate balance and convergence, and to avoid interference with oil pressure due to drastic changes in the second flow velocity value qr.

[0055] In S3, the oil pressure deviation value e_p = first threshold Ptarget - real-time oil pressure value Pi, and the cumulative flow deviation value e_q = first cumulative flow value Ql - second cumulative flow value Qr. If the oil pressure deviation value e_q is positive, it means that the real-time oil pressure value Pi < first threshold Ptarget (oil pressure is too low); if it is negative, it means that the real-time oil pressure value Pi > first threshold Ptarget (oil pressure is too high).

[0056] The first target flow rate ql_target = the first flow rate value ql + the flow rate adjustment amount Δql of the first fuel pump 231, that is, the formula for the target flow rate of the first fuel pump 231 is: ql_target = ql_current + Δql (ql_current is the current first flow rate value); the second target flow rate qr_target = the second flow rate value qr_current + the flow rate adjustment amount Δqr of the second fuel pump 232, that is, the formula for the target flow rate of the second fuel pump 232 is: qr_target = qr_current + Δqr (qr_current is the current second flow rate value).

[0057] In S5, repeat S1-S4, and adjust the flow rate regulation amount Δql of the first fuel pump 231 and the flow rate regulation amount Δqr of the second fuel pump 232 according to the new first cumulative flow value Ql, second cumulative flow value Qr and real-time oil pressure value Pi, until the oil pressure deviation value e_p and the cumulative flow deviation value e_q simultaneously meet the requirements.

[0058] Furthermore, S5 reduces mutual interference between the two logic loops in the following two ways:

[0059] 1. Physical level: The oil tank 22 is connected to the buffer 24. When the oil pressure changes, the buffer gas in the gas cylinder is compressed or expanded first, so that the oil pressure change is smoother and the sudden change in oil pressure is avoided, which will cause the system to oscillate more.

[0060] 2. Control Level: If the second fuel pump 232 adjusts the second flow rate value qr, and the change in total flow (first flow rate value ql + second flow rate value qr) causes the real-time fuel pressure value Pi to deviate from the target (e.g., the second flow rate value qr suddenly increases → total flow increases → real-time fuel pressure value Pi rises): the fuel pressure PID of the first fuel pump 231 will respond immediately, and adjust the first flow rate value ql to offset the influence of the second flow rate value qr (e.g., the second flow rate value qr increases → the first flow rate value ql decreases appropriately to maintain a stable total flow); if the first fuel pump 231 adjusts the first flow rate value ql, and the change in the growth rate of the first cumulative flow value Ql causes a flow deviation (e.g., the first flow rate value ql suddenly increases → the growth rate of the first cumulative flow value Ql accelerates → the first cumulative flow value Ql - the second cumulative flow value Qr becomes larger): the flow PID of the second fuel pump 232 will respond, and adjust the second flow rate value qr (increase the second flow rate value qr) to balance the difference between the first cumulative flow value Ql and the second cumulative flow value Qr.

[0061] This control method achieves decoupled control of two objectives through a dual PID design: "independent control of fuel pressure by the first fuel pump 231 and independent control of flow balance by the second fuel pump 232".

[0062] I. The oil pressure control uses the first fuel pump 231 as the actuator. The first flow rate value ql is adjusted by PID to directly affect the total flow rate and quickly correct the oil pressure deviation value.

[0063] II. Flow balancing uses the second fuel pump 232 as the actuator. By adjusting the second flow velocity value qr through PID control, the growth rate of the second cumulative flow value Qr is changed, and the cumulative flow difference is gradually reduced.

[0064] By employing a dual PID control method, the feedback of total flow and cumulative flow naturally coordinates, canceling out mutual interference, and ultimately achieving the dual objectives of |real-time oil pressure value Pi - first threshold Ptarget| < 10 kPa and |first cumulative flow value Ql - second cumulative flow value Qr| < 100 g.

[0065] Beneficial effects: It can not only filter impurities and balance the center of gravity of the aircraft, but also ensure the stability of oil pressure.

[0066] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0067] In the description of this specification, the references to terms such as "preferred embodiment," "another embodiment," "other embodiment," or "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0068] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A fuel control device characterized by comprising: include: A controller (21) and a fuel tank (22) are provided. A fuel extraction unit (23) is provided at one end of the fuel tank (22), and a buffer (24) is provided at the other end of the fuel tank (22). The controller (21) is electrically connected to the fuel extraction unit (23). The fuel extraction unit (23) includes a first fuel pump (231) and a second fuel pump (232). A first flow meter (2312) is connected to the first fuel pump (231). The first fuel pump (231) is connected to the oil collection tank (22) through the first flow meter (2312). A second flow meter (2322) is connected to the second fuel pump (232). The second fuel pump (232) is connected to the oil collection tank (22) through the second flow meter (2322). By adjusting the speed of the first fuel pump (231) and the second fuel pump (232) based on the cumulative flow difference between the first flow meter (2312) and the second flow meter (2322), the fuel center of gravity is balanced.

2. The fuel control apparatus of claim 1 wherein, It also includes a first filter (2311) and a second filter (2321), which are connected to the first fuel pump (231) and the second fuel pump (232), respectively.

3. The fuel control apparatus of claim 1 wherein, The buffer (24) is equipped with an exhaust valve (241).

4. The fuel control apparatus of claim 1 wherein, The oil collection tank (22) includes a tank body (221), a front cover (222) is provided at the front end of the tank body (221), and a rear cover (223) is provided at the rear end of the tank body (221). The front cover (222) is provided with a pressure sensor (224) and two one-way valves (225), and the first flow meter (2312) and the second flow meter (2322) are respectively connected to the one-way valves (225); The rear cover (223) is provided with an oil outlet, which is located below the surface of the rear cover (223). The box (221) is provided with a weight (226), which is a through hollow structure. The weight (226) is connected to the oil outlet through a hose (2261) so that the weight (226) is located inside the bottom of the box (221). The front cover (222) and the rear cover (223) are fixed to the front and rear ends of the box body (221) respectively by multiple connecting rods (227).

5. The fuel control apparatus of claim 4 wherein, The front cover (222) and the rear cover (223) are respectively provided with a sealing groove (2221), the box body (221) is embedded in the sealing groove (2221), and a sealant is provided at the joint to achieve sealing.

6. The fuel control apparatus of claim 4 wherein, There are four connecting rods (227). The connecting rods (227) are hollow metal rods with internal threads. The connecting rods (227) are connected to the front cover (222) and the rear cover (223) by bolts.

7. The fuel control apparatus of claim 2 wherein, The first filter (2311) and the second filter (2321) are metal mesh filters, the first flow meter (2312) and the second flow meter (2322) are gear-type volumetric flow meters, and the first fuel pump (231) and the second fuel pump (232) are gear pumps or centrifugal pumps.

8. An aircraft, characterized in that include: An engine body (1) is provided with a fuel control device (2) as described in any one of claims 1-7.

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