A dual gear pump oil supply system architecture and dual-mode conversion method

Abstract

This application provides a dual-gear pump fuel supply system architecture and dual-mode conversion method, belonging to the technical field of aircraft engine fuel and control systems. Specifically, the system includes a fuel tank, a low-pressure centrifugal pump, a dual-gear pump, a check valve, a return valve, a metering device, sensors, and pipelines. It features a dual-path fuel return system. A first return line is provided between the metering device and the fuel tank, allowing excess fuel after metering to return to the tank. A second return line is provided between the inlet and outlet of the second gear pump, with an electronically controlled return valve located in the middle of the line. This system has two fuel supply operating modes: the first, in which the low-flow first gear pump independently supplies fuel, while the high-flow second gear pump operates at no load; the second, in which the first and second gear pumps simultaneously supply fuel in parallel, with the second return line closed. The proposed conversion between the two fuel supply operating modes utilizes a control method based on the characteristic model of the small gear pump, effectively ensuring that the engine operates in the first fuel supply mode for more than 95% of its flight time.

Description

Technical Field

[0001] The present application relates to the field of aviation engine fuel and control systems, and in particular to a dual-gear pump oil supply system architecture and a dual-mode conversion method. Background Art

[0002] In aircraft engines, the fuel supply system is a key energy supply subsystem, which is mainly used to realize the fuel supply function required for engine combustion while ensuring the temperature rise and power consumption of the fuel system.

[0003] Since the fuel flow requirements of aircraft engines vary greatly under different flight conditions, the fuel flow can be adjusted in a wide range. Using a single pump with a wide range and large flow to supply fuel means that the fuel pump operating point is always far away from the optimal performance point, causing the fuel system temperature to rise and power consumption to increase, resulting in waste, and is not conducive to heat exchange and heat sink management of the fuel / lubricating oil system, posing a safety hazard to the engine.

[0004] Analysis of typical aircraft engine flight profiles shows that high-flow fuel delivery is a significantly low percentage of the time, accounting for approximately 1%-5% of the total flight mission time. Fuel system design often requires the fuel pump to operate at its rated state to ensure maximum fuel flow demand. However, the engine's most frequent operating state is cruise, where fuel flow demand accounts for approximately 38% of the maximum flow demand. This forces the fuel pump to operate at a non-rated state for extended periods, resulting in lower efficiency, increased temperature rise, and high fuel return volume, leading to significant power consumption and energy loss. Using a single low-flow pump operating at its optimal performance point in this state would reduce fuel return by approximately 50%-70%, lowering fuel system temperature rise and reducing pump power consumption. Therefore, it is necessary to optimize the fuel system architecture to ensure that the fuel pump consistently operates at a near-optimal performance point while meeting the main fuel delivery demand.

[0005] The main fuel system typically uses a metering gear pump. When the combustion chamber's required flow rate is significantly less than the pump's supply flow rate, a large amount of excess fuel must be returned to the lower-pressure fuel system inlet. This generates heat, causing the inlet fuel temperature to increase. The fuel pump's pressure increase also causes a temperature rise, further exacerbating the temperature rise and raising the overall equilibrium temperature of the fuel system. Prolonged circulation can cause increased wear on the gear pump, and in severe cases, even damage it. Furthermore, excessively high fuel temperatures reduce the fuel's thermal stability, easily forming heat sinks within the fuel, potentially clogging the engine's filters and causing engine fuel system failures, impacting aircraft safety and reliability. Summary of the Invention

[0006] In view of this, the present application provides a dual-gear pump oil supply system architecture and a dual-mode conversion method, which solves the problems of large energy loss and increased fuel temperature under most working conditions in the fuel supply system in the prior art, effectively improves the heat exchange capacity of the fuel system, and improves the safety and reliability of aircraft flight.

[0007] On the one hand, the present application provides a dual gear pump oil supply system architecture that adopts the following technical solutions:

[0008] A double gear pump oil supply system architecture, comprising:

[0009] Fuel tank, storing oil;

[0010] A double gear pump, comprising a first gear pump and a second gear pump, wherein the flow rate of the first gear pump is smaller than the flow rate of the second gear pump, the first gear pump and the second gear pump are both connected to the output pipe of the oil tank, and the first gear pump and the second gear pump are connected in parallel;

[0011] A metering device, the outlet of the first gear pump is connected to the metering device through a first pipeline, and the outlet of the second gear pump is connected to the metering device through a second pipeline. A one-way valve is provided on the second pipeline. The metering device combines the fuel of the first gear pump and the second gear pump, calculates the fuel supply to the combustion chamber according to the throttle lever, the engine high-pressure speed, and the engine inlet temperature, and drives the hydraulic valve opening through the actuator to supply fuel to the main combustion chamber. The one-way valve is opened when the outlet pressure of the second gear pump is not less than the pressure of the first gear pump, otherwise it is not opened.

[0012] Optionally, the output pipe of the oil tank is connected to the first gear pump and the second gear pump through a low-pressure centrifugal pump, and the output pipe of the low-pressure centrifugal pump is connected to the inlets of the first gear pump and the second gear pump.

[0013] Optionally, the outlet of the second gear pump is provided with two outputs, one output is connected to the metering device, and the other output is provided with an oil return valve, and the outlet of the oil return valve is connected to the inlet of the duplex gear pump.

[0014] Optionally, the metering device is provided with a first oil return pipeline connected to the oil tank output pipe.

[0015] Optionally, temperature sensors are provided on the output pipe of the oil tank and the output pipe of the metering device.

[0016] Optionally, a pressure sensor is provided on the pipeline between the outlet of the first gear pump and the inlet of the metering device to measure the outlet pressure of the first gear pump.

[0017] On the other hand, the present application provides a dual-mode conversion method for a dual gear pump oil supply system architecture using the following technical solutions:

[0018] A dual-mode conversion method for a double gear pump oil supply system architecture, wherein the double gear pump oil supply system architecture includes the above-mentioned double gear pump oil supply system architecture, and the dual-mode conversion method for the double gear pump oil supply system architecture includes:

[0019] Step 1: Establish the first gear pump model, WfRe=f(N2, Pf1), where N2 is the percentage of engine speed and Pf1 is the pressure after the first gear pump;

[0020] Step 2: Calculate the theoretical oil flow rate WfRe(t) of the first gear pump at the current speed and pressure in real time;

[0021] Step 3: Calculate the relative change in the difference between WfDem(t) at the current time t and WfRe(t) calculated by the first gear pump model in real time according to the control system, and compare it with the set threshold W0. If it is greater than W0, output the command to turn on the oil return valve;

[0022] Step 4: Output the oil return valve control instruction according to the judgment result of step 3;

[0023] Step 5: Calculate the temperature rise of the fuel system and set the temperature rise threshold. When the following formula is met, the return valve open signal is output. The calculation formula is as follows: ΔT f =(T f -T fin )≥T f0 ;

[0024] Where: T f is the fuel temperature at the outlet of the metering device, T fin is the fuel system inlet temperature, T f0 is the temperature rise threshold;

[0025] According to the conclusions drawn in step 4 and step 5, if one of them is established, the return valve opening control instruction is output to make the double gear pump oil supply system work in the single pump working mode, otherwise it works in the double pump working mode.

[0026] Optionally, in step 2, an interpolation method is used to calculate in real time the theoretical oil supply flow rate WfRe(t) at the current speed and pressure of the first gear pump.

[0027] Optionally, in step 3, the dual pump operation mode is switched when the relative change in the difference between WfDem(t) at the current moment t and WfRe(t) calculated by the first gear pump model is less than or equal to the set threshold W0 minus 0.03.

[0028] In summary, this application has the following beneficial technical effects:

[0029] The twin gear pump oil supply system architecture and dual-mode conversion method can adjust the working mode of the twin gear pump according to the engine fuel flow demand. Compared with mechanical hydraulic adjustment, the operability is significantly improved and the adaptability is enhanced.

[0030] Tests have shown that in single-pump mode (with the first gear pump supplying oil independently), the maximum power consumption of the twin gear pump is 14kW, and the fuel system temperature rises by 16°C (without a fuel / lubricating oil radiator). This is significantly lower than the 35kW power consumption and 52°C temperature rise of a wide-range, high-flow gear pump supplying oil independently. In dual-pump mode (with dual gear pumps supplying oil in parallel), the twin gear pumps have no significant advantages in power consumption and temperature rise. The single-pump mode usage rate reaches 95% throughout the engine's life cycle, ensuring reduced power consumption and temperature rise for most of the operating time. Without increasing the weight of the system (the weight of the integrated twin gear pump does not increase), this application offers significant advantages.

[0031] The dual gear pump fuel supply system architecture offers greater reliability. If one pump fails, the other pump can still ensure engine operation at low operating conditions, improving fuel system reliability and ensuring flight safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 This is a block diagram of the double gear pump oil supply system architecture;

[0034] Figure 2 The control logic block diagram of the dual-mode conversion method for the double gear pump oil supply system architecture.

[0035] Explanation of the accompanying drawings: 1. Oil tank; 2. Low-pressure centrifugal pump; 3. Duplex gear pump; 31. First gear pump; 32. Second gear pump; 4. Metering device; 6. Return oil valve; 7. One-way valve; 8. Second return oil pipe; 9. First return oil pipe; 10. Second pipeline; 11. First pipeline; 12. Temperature sensor; 14. Pressure sensor. DETAILED DESCRIPTION

[0036] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0037] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0038] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0039] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0040] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details.

[0041] An embodiment of the present application provides a dual gear pump oil supply system architecture.

[0042] An embodiment of the present application provides a dual gear pump oil supply system architecture.

[0043] like Figure 1 As shown, a double gear pump oil supply system architecture includes:

[0044] Oil tank 1, storing oil source.

[0045] The low-pressure centrifugal pump 2 slightly increases the fuel pressure (by 0.5 MPa to 1.5 MPa), with its inlet connected to the fuel tank 1 and its outlet connected to the duplex gear pump 3;

[0046] The double gear pump 3 includes a first gear pump 31 and a second gear pump 32. The rated oil supply flow rate of the first gear pump 31 is much smaller than that of the second gear pump 32, with a rated flow rate ratio of approximately 1:3. The inlets of the first gear pump 31 and the second gear pump 32 are both connected to the output pipe of the low-pressure centrifugal pump 2. The first gear pump 31 and the second gear pump 32 are connected in parallel and share a common transmission shaft to form an integrated combination pump. The weight of the combination pump is equivalent to that of an independent high-flow oil supply gear pump;

[0047] Metering device 4 receives fuel from the twin gear pumps 3 and adjusts the fuel flow rate to the main combustion chamber based on control commands. The outlet of the first gear pump 31 in the twin gear pumps 3 is connected to the metering device via pipeline 11, while the outlet of the second gear pump 32 is connected to the metering device 4 via pipeline 10, which is equipped with a check valve 7. The control commands are output by the control system. The metering device 4 discharges excess fuel after metering into the oil return chamber, which then returns it to the tank inlet via the first oil return pipeline 9.

[0048] The system is not limited to components such as fuel filter, radiator, throttle valve, pressure differential valve, and flow collecting valve added to realize other auxiliary functions.

[0049] The outlet of the second gear pump 32 is connected to two pipelines. One pipeline is connected to the metering device 4, with a one-way valve 7 interposed in between. The other pipeline is connected to the inlet of the second gear pump, and a return valve 6 is installed on the pipeline 8. The return valve 6 can receive control commands to execute the opening and closing functions of the second return oil pipe 8. The return valve 6 is a normally open electromagnetic unloading valve. When it does not receive a control signal, it is normally open, that is, the fuel system operates in the first fuel supply operating mode. The control system calculates and compares parameters such as fuel pressure Pf1, temperature Tf, fuel flow rate WfDem, and engine speed N2, and then outputs an open or close control command to act on the normally open electromagnetic unloading valve. When the return valve 6 is open, it is in the first fuel supply operating mode. When the return valve 6 is closed, it is in the second fuel supply operating mode.

[0050] The fuel metering device 4 calculates the fuel supply amount WfDem for the combustion chamber based on the throttle lever PLA, the engine high-pressure speed N2, and the engine inlet temperature T2, and drives the opening of the hydraulic valve through the actuator to supply fuel to the main combustion chamber according to WfDem. If the combined fuel supply amount is greater than WfDem, the excess fuel is discharged into the return oil chamber.

[0051] Temperature sensors 12 are respectively provided on the outlet pipe of the fuel tank 1 and the output pipe of the metering device 4 to measure the temperature of the fuel system.

[0052] A pressure sensor 14 is provided on the pipeline between the outlet of the first gear pump 31 and the inlet of the metering device 4 to measure the outlet pressure of the first gear pump 31 .

[0053] The dual-mode conversion algorithm integrated into the control system calculates and outputs a control command for the oil return valve 6 based on the fuel temperature rise ΔTf, the pump outlet pressure Pf1, the fuel flow rate WfRe, and the engine speed N2. If the control command is "on," the normally-open solenoid unloading valve is de-energized, the second oil return line 8 is open, and the inlet and outlet lines of the second gear pump 32 are connected, with almost no pressure increase, minimizing power consumption. Since pressure increase is proportional to temperature rise, the temperature rise of the second gear pump 32 is also very small, and the system enters the first fuel supply mode. Simultaneously, the check valve 7 closes due to the drop in pressure after the second gear pump 32, preventing fuel backflow through the metering device 4. If the control command is "off," the normally-open solenoid unloading valve is energized, the second oil return line 8 is disconnected, and the second gear pump 32 begins to increase pressure. The check valve 7 opens when it senses that the pressure after the second gear pump 32 exceeds a threshold. At this point, the second gear pump 32 and the first gear pump 31 simultaneously supply fuel to the main combustion chamber through the metering device 4, and the system enters the second fuel supply mode.

[0054] The embodiment of the present application also discloses a dual-mode conversion method for a dual gear pump oil supply system architecture.

[0055] like Figure 2 As shown, a dual-mode conversion method of a double gear pump oil supply system architecture is provided. The double gear pump oil supply system architecture is the above-mentioned double gear pump oil supply system architecture. The dual-mode conversion method of the double gear pump oil supply system architecture includes:

[0056] Step 1: Establish the first gear pump model, WfRe=f(N2, Pf1), where N2 is the percentage of engine speed and Pf1 is the pressure after the first gear pump.

[0057] Step 2: Calculate the theoretical oil flow rate WfRe(t) of the first gear pump at the current speed and pressure in real time.

[0058] Step 3: The control system calculates the relative change in the difference between WfDem(t) at the current moment t and WfRe(t) calculated by the first gear pump model in real time, and compares it with the set threshold W0. When it is greater than W0, the return valve conduction instruction is output. The calculation formula is as follows:

[0059]

[0060] Step 4: Output the oil return valve control instruction according to the judgment result of step 3.

[0061] Step 5, calculate the fuel system temperature rise (attached Figure 21007), set the temperature rise threshold, and output the oil return valve opening signal when the following formula is met. The calculation formula is as follows: ΔT f =(T f -T fin )≥T f0 .

[0062] Where: T f is the fuel temperature at the outlet of the metering device, T fin is the fuel system inlet temperature, T f0 is the temperature rise threshold.

[0063] According to the conclusions drawn in step 4 and step 5, if one of them is established, the return valve opening control instruction is output to make the double gear pump oil supply system work in the single pump working mode, otherwise it works in the double pump working mode.

[0064] ((Tf-Tfin)≥Tf0or(WfRe-WfDem) / WfRe≥W0)=true

[0065] Step 1: Based on the pressure-speed-flow characteristics of the small flow gear pump, a calculation model for the WfRe parameter is developed (see Appendix Figure 2 The model is obtained based on the performance test data of the small flow gear pump, and the model data after normalization is shown in Table 1.

[0066] Table 1 WfRe calculation model of the first gear pump

[0067]

[0068]

[0069] In step 2, the nearest neighbor interpolation method is used to calculate the theoretical oil supply flow rate WfRe(t) at the current speed and pressure of the first gear pump in real time.

[0070] The nearest neighbor interpolation method calculation formula is:

[0071]

[0072] Where t represents the current time, N represents the number of samples in the array [N2(i), Pf1(i), WfRe(i)] in the model, i represents the array number of the i-th sample, and p represents the relative importance of the distant sample of the estimated point, which is generally set to 4. WfRe(t) represents the theoretical oil flow rate of the first gear pump at time t, N2(t) represents the percentage of the measured engine speed at time t, and Pf1(t) represents the measured outlet pressure of the first gear pump at time t.

[0073] In step 3, when the relative change in the difference between WfDem(t) at the current time t and WfRe(t) calculated by the first gear pump model is less than or equal to the set threshold W0 minus 0.03, the dual-pump working mode is switched, as shown in the following formula:

[0074]

[0075] In engineering practice, the threshold W0 in step 3 is an adjustable parameter, which can be adjusted according to test verification results or fuel pump performance degradation.

[0076] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A dual-mode conversion method for a dual gear pump oil supply system architecture, characterized in that: The double gear pump oil supply system architecture includes: Fuel tank, storing oil; A double gear pump, comprising a first gear pump and a second gear pump, wherein the flow rate of the first gear pump is smaller than the flow rate of the second gear pump, the first gear pump and the second gear pump are both connected to the output pipe of the oil tank, and the first gear pump and the second gear pump are connected in parallel; A metering device, wherein the outlet of the first gear pump is connected to the metering device via a first pipeline, and the outlet of the second gear pump is connected to the metering device via a second pipeline. A one-way valve is provided on the second pipeline. The metering device combines the fuel from the first gear pump and the second gear pump, calculates the fuel supply to the combustion chamber based on the throttle lever, the engine high-pressure speed, and the engine inlet temperature, and drives the opening of the hydraulic valve through an actuator to supply fuel to the main combustion chamber. The one-way valve is opened when the outlet pressure of the second gear pump is not less than the pressure of the first gear pump, and is closed otherwise. The dual-mode conversion method of the double gear pump oil supply system architecture includes: Step 1: Establish the first gear pump model, WfRe=f(N2, Pf1), where N2 is the percentage of engine speed and Pf1 is the pressure after the first gear pump; Step 2: Calculate the theoretical oil flow rate WfRe(t) of the first gear pump at the current speed and pressure in real time; Step 3: Calculate the relative change in the difference between WfDem(t) at the current time t and WfRe(t) calculated by the first gear pump model in real time according to the control system, and compare it with the set threshold W0. If it is greater than W0, output the command to turn on the oil return valve; Step 4: Output the oil return valve control instruction according to the judgment result of step 3; Step 5: Calculate the temperature rise of the fuel system and set the temperature rise threshold. When the following formula is met, the return valve is output as an electrical signal to open. The calculation formula is as follows: ; in: is the fuel temperature at the outlet of the metering device, is the fuel system inlet temperature, is the temperature rise threshold; According to the conclusions drawn in step 4 and step 5, if one of them is established, the return valve opening control instruction is output to make the double gear pump oil supply system work in the single pump working mode, otherwise it works in the double pump working mode.

2. The dual-mode conversion method of the dual gear pump oil supply system architecture according to claim 1, characterized in that: In step 2, the interpolation method is used to calculate in real time the theoretical oil supply flow rate WfRe(t) at the current speed and pressure of the first gear pump.

3. The dual-mode conversion method of the dual gear pump oil supply system architecture according to claim 2, characterized in that: In step 3, the dual pump operation mode is switched when the relative change in the difference between WfDem(t) at the current time t and WfRe(t) calculated by the first gear pump model is less than or equal to the set threshold W0 minus 0.

03.

4. The dual-mode conversion method of the dual gear pump oil supply system architecture according to claim 1, characterized in that: The output pipe of the oil tank is connected to the first gear pump and the second gear pump through a low-pressure centrifugal pump, and the output pipe of the low-pressure centrifugal pump is connected to the inlets of the first gear pump and the second gear pump.

5. The dual-mode conversion method of the dual gear pump oil supply system architecture according to claim 1, characterized in that: The outlet of the second gear pump is provided with two outputs, one output is connected to the metering device, and the other output is provided with an oil return valve, the outlet of the oil return valve is connected to the inlet of the duplex gear pump.

6. The dual-mode conversion method of the dual gear pump oil supply system architecture according to claim 1, characterized in that: The metering device is provided with a first oil return pipeline connected to the oil tank output pipe.

7. The dual-mode conversion method of the dual gear pump oil supply system architecture according to claim 1, characterized in that: Temperature sensors are provided on the output pipe of the oil tank and the output pipe of the metering device.

8. The dual-mode conversion method of the dual gear pump oil supply system architecture according to claim 1, characterized in that: A pressure sensor is provided on the pipeline between the outlet of the first gear pump and the inlet of the metering device to measure the outlet pressure of the first gear pump.

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