Oil pump assembly suitable for piston aircraft engine and piston aircraft engine

Abstract

The present invention discloses an oil pump assembly suitable for a piston aircraft engine, comprising a first low-pressure oil pump, a second low-pressure oil pump, a casing, a first one-way valve connected to the oil outlet of the first low-pressure oil pump, a second one-way valve connected to the oil outlet of the second low-pressure oil pump, a fuel pressure accumulator rail connected to the first one-way valve and the second one-way valve, a fuel pressure sensor arranged on the fuel pressure accumulator rail, and a pressure regulating valve connected to the oil outlet of the fuel pressure accumulator rail. The first low-pressure oil pump, the second low-pressure oil pump, the first one-way valve, the second one-way valve and the pressure regulating valve are arranged inside the casing. The present invention is suitable for an oil pump assembly of a piston aircraft engine, can reduce system complexity, and has a high degree of integration. The present invention also provides a piston aircraft engine.

Description

Technical Field

[0001] The present invention belongs to the technical field of engines, and in particular, relates to an oil pump assembly suitable for a piston aircraft engine and the piston aircraft engine. Background Art

[0002] Piston aircraft engines have been widely used in fixed-wing and rotary-wing aircraft, and are very widely used in civil and military unmanned aerial vehicles and general aviation aircraft. The development of piston aircraft engines has gone through the stages of carburetor gasoline engines and mechanical pump diesel engines, and is currently gradually developing towards electronically controlled gasoline engines, electronically controlled common rail diesel engines, and heavy oil engines. As for the application of common rail diesel engines, ensuring the safety of the low-pressure oil system is a key research topic.

[0003] In the aviation field, the design of redundant key components is adopted as one of the important means to ensure the safety of the system. In common rail diesel engines, FADEC dual-channel system control, redundant design of key sensors and actuators and other solutions are mature in application. As the fuel supply system design of common rail diesel engines, dual low-pressure oil pumps are adopted. At the same time, necessary monitoring measures are designed to ensure sufficient safety, which is an important means to ensure the robustness of the fuel system.

[0004] The design of dual low-pressure oil pumps for engines faces the following obvious risks:

[0005] 1. High system complexity: Under the premise of meeting the requirements of overall engine performance and reliability, the system should be designed to be as simple as possible. The higher the system complexity, the more potential failure risk points it brings, and it is also not conducive to achieving the lightweight design of the engine and the power-to-weight ratio goals. It is difficult for electronically controlled gasoline engines to achieve closed-loop control and adjustment of the oil intake and injector injection amount. It is difficult to complete the closed-loop timely adjustment of the system injection amount when the low-pressure oil pump's oil output fluctuates greatly. Electronically controlled gasoline engines usually use a series of dual low-pressure oil pumps. The output flow of the series oil pump is not much different when the dual pumps work and the single pump works, which can better meet the working needs of the gasoline engine. In principle, this type of tandem low-pressure oil pump can be transplanted and applied to common rail diesel engines. However, because the tandem low-pressure oil pump system needs to design a bypass passage to ensure that when a single low-pressure oil pump is damaged, the fuel can enter the oil inlet of the high-pressure oil pump through the bypass passage. The bypass passage must be equipped with a one-way valve to ensure that the fuel does not flow back into the fuel tank and when a single pump stops working, another oil pump can suck or deliver oil through the bypass passage one-way valve. The one-way valve must have a sufficiently small opening pressure and a small pressure loss to ensure that when the low-pressure oil pump close to the fuel tank is damaged, another low-pressure oil pump in series can suck the one-way valve open and draw oil from the bypass passage. The overall complexity of the system increases, and the failure caused by the sticking and blockage of the one-way valve, the leakage and aging of the bypass line, etc., bring new risk points to the low-pressure oil circuit. Therefore, the widely used tandem low-pressure oil pump solution has a high system complexity and great potential risk points, and is not a good choice for common rail diesel engines.

[0006] 2. System consistency is difficult to control: The different relative positions of the dual low-pressure oil pumps, pressure regulating valves, and sensors in the low-pressure fuel system, due to the different lengths, bends, and losses along the connecting pipelines, will cause differences in parameters such as fuel pressure and temperature at the inlet of the high-pressure oil pumps of different engines. This difference will change the calibrated and solidified fuel inlet parameters of the engine, affecting the consistency of the entire engine system. Therefore, the risk of difficult control of system consistency caused by the scattered arrangement of components in the system is a problem that is difficult to solve at present;

[0007] 3. The fault alarm strategy lacks a simple and effective solution. Summary of the invention

[0008] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an oil pump assembly suitable for a piston aircraft engine, the purpose of which is to reduce system complexity.

[0009] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an oil pump assembly suitable for a piston aircraft engine, including a first low-pressure oil pump, a second low-pressure oil pump, a casing, a first one-way valve connected to the oil outlet of the first low-pressure oil pump, a second one-way valve connected to the oil outlet of the second low-pressure oil pump, a fuel pressure accumulator rail connected to the first one-way valve and the second one-way valve, a fuel pressure sensor arranged on the fuel pressure accumulator rail, and a pressure regulating valve connected to the oil outlet of the fuel pressure accumulator rail, and the first low-pressure oil pump, the second low-pressure oil pump, the first one-way valve, the second one-way valve and the pressure regulating valve are arranged inside the casing.

[0010] The first low-pressure oil pump and the second low-pressure oil pump are arranged side by side inside the box, and the first low-pressure oil pump and the second low-pressure oil pump are located on the same side of the fuel pressure accumulator rail.

[0011] The first low-pressure oil pump, the second low-pressure oil pump and the pressure regulating valve are located on the same side of the fuel pressure accumulator rail, and the first low-pressure oil pump is located between the second low-pressure oil pump and the pressure regulating valve.

[0012] When the first low-pressure fuel pump is working and the second low-pressure fuel pump is not working, the detection result of the fuel pressure sensor corresponds to the system fuel pressure when the first low-pressure fuel pump is damaged.

[0013] The oil pump assembly suitable for a piston aircraft engine also includes a shock-absorbing pad arranged inside the housing and made of a soft material, wherein the shock-absorbing pad is located between the first low-pressure oil pump, the second low-pressure oil pump and the housing.

[0014] The shock-absorbing pad is made of rubber material.

[0015] The oil inlets of the first low-pressure oil pump and the second low-pressure oil pump are both provided with pressure relief valves.

[0016] The box body comprises a lower shell and an upper cover connected with the lower shell.

[0017] The present invention also provides a piston aircraft engine, comprising the above-mentioned oil pump assembly.

[0018] The invention is applicable to the oil pump assembly of a piston aircraft engine, can reduce the complexity of the system and has a high degree of integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] This specification includes the following drawings, which show the following contents:

[0020] Figure 1 It is an exploded schematic diagram of an oil pump assembly applicable to a piston aircraft engine of the present invention;

[0021] Figure 2It is a schematic diagram of the fuel flow of the oil pump assembly applicable to a piston aircraft engine of the present invention;

[0022] The markings in the figure are: 1. Upper cover; 2. Fuel pressure sensor; 3. Fuel pressure accumulator rail; 4. Fuel rail plug; 5. Pressure regulating valve; 6. First low-pressure oil pump; 7. Shock absorber pad; 8. Lower shell; 9. Pressure relief valve; 10. Oil pump clamp; 11. Second low-pressure oil pump; 12. First wiring harness plug-in; 13. First non-return valve; 14. Second non-return valve; 15. First oil inlet pipe; 16. Second oil inlet pipe; 17. Oil outlet pipe; 18. Second wiring harness plug-in; 19. Oil return port. DETAILED DESCRIPTION

[0023] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0024] It should be noted that, in the following embodiments, the “first” and “second” mentioned do not represent an absolute distinction in structure and / or function, nor do they represent a sequential order of execution, but are merely for the convenience of description.

[0025] like Figure 1 and Figure 2 As shown, the present invention provides an oil pump assembly suitable for a piston aircraft engine, comprising a first low-pressure oil pump 6, a second low-pressure oil pump 11, a casing, a first one-way valve 13 connected to the oil outlet of the first low-pressure oil pump 6, a second one-way valve 14 connected to the oil outlet of the second low-pressure oil pump 11, a fuel pressure accumulator rail 3 connected to the first one-way valve 13 and the second one-way valve 14, a fuel pressure sensor 2 arranged on the fuel pressure accumulator rail 3, a pressure regulating valve 5 connected to the oil outlet of the fuel pressure accumulator rail 3, and an oil outlet pipe 17 connected to the pressure regulating valve 5. The first low-pressure oil pump 6, the second low-pressure oil pump 11, the first one-way valve 13, the second one-way valve 14 and the pressure regulating valve 5 are arranged inside the casing.

[0026] Specifically, if Figure 1 and Figure 2As shown, the box is a rectangular structure with a hollow interior, and the first low-pressure oil pump 6 and the second low-pressure oil pump 11 are arranged side by side inside the box, and the first low-pressure oil pump 6 and the second low-pressure oil pump 11 are located on the same side of the fuel pressure accumulator rail 3. The length direction of the first low-pressure oil pump 6 and the second low-pressure oil pump 11 is parallel to the length direction of the box, and the first low-pressure oil pump 6 and the second low-pressure oil pump 11 are on the same straight line parallel to the width direction of the box, and the length direction of the fuel pressure accumulator rail 3 is parallel to the width direction of the box, and the fuel pressure accumulator rail 3 is located at one end of the length direction of the box, and the fuel pressure accumulator rail 3 is fixedly connected to the box. The first low-pressure oil pump 6, the second low-pressure oil pump 11 and the pressure regulating valve 5 are located on the same side of the fuel pressure accumulator rail 3, and the first low-pressure oil pump 6 is located between the second low-pressure oil pump 11 and the pressure regulating valve 5, and the first low-pressure oil pump 6, the second low-pressure oil pump 11 and the pressure regulating valve 5 are on the same straight line parallel to the width direction of the box, and the pressure regulating valve 5 is fixedly connected to the box.

[0027] like Figure 1 and Figure 2 As shown, the piston aircraft engine is a diesel engine, and the oil outlet pipe 17 is used to guide the fuel from the pressure regulating valve 5 to the fuel fine filter of the piston aircraft engine. The fuel filtered by the fuel fine filter flows to the high-pressure oil pump of the piston aircraft engine, and the high-pressure oil pump supplies oil to the fuel rail of the piston aircraft engine. One end of the oil outlet pipe 17 is connected to the oil outlet of the pressure regulating valve 5, and the other end of the oil outlet pipe 17 passes through the side wall of the box and extends toward the outside of the box. The oil inlet of the pressure regulating valve 5 is connected to the oil outlet of the fuel pressure accumulator rail 3, and the length direction of the oil outlet pipe 17 is parallel to the length direction of the box.

[0028] like Figure 1 and Figure 2As shown, the oil inlet of the first low-pressure oil pump 6 is connected to the first oil inlet pipe 15, the oil inlet of the second low-pressure oil pump 11 is connected to the second oil inlet pipe 16, the first oil inlet pipe 15 and the second oil inlet pipe 16 are located outside the box, the first oil inlet pipe 15 and the second oil inlet pipe 16 are arranged side by side, the first oil inlet pipe 15, the second oil inlet pipe 16 and the oil outlet pipe 17 are on the same straight line parallel to the width direction of the box, and the first oil inlet pipe 15 and the second oil inlet pipe 16 are connected to the fuel tank. The oil outlet of the first low-pressure oil pump 6 is connected to the oil inlet of the first check valve 13, the oil outlet of the first check valve 13 is connected to one oil inlet of the fuel pressure accumulator rail 3, the oil outlet of the second low-pressure oil pump 11 is connected to the oil inlet of the second check valve 14, and the oil outlet of the second check valve 14 is connected to the other oil inlet of the fuel pressure accumulator rail 3. The first one-way valve 13 allows the fuel to flow only from the first low-pressure oil pump 6 to the fuel pressure accumulator rail 3, and the fuel in the fuel pressure accumulator rail 3 cannot flow back to the first low-pressure oil pump 6 through the first one-way valve 13. Similarly, the second one-way valve 14 allows the fuel to flow only from the second low-pressure oil pump 11 to the fuel pressure accumulator rail 3, and the fuel in the fuel pressure accumulator rail 3 cannot flow back to the second low-pressure oil pump 11 through the second one-way valve 14. Therefore, by setting two one-way valves, the fuel pumped out of the two low-pressure oil pumps is prevented from flowing back to the low-pressure oil pumps, and the fuel pumped out of the first low-pressure oil pump 6 and the fuel pumped out of the second low-pressure oil pump 11 merge in the fuel pressure accumulator rail 3. The function of the fuel pressure accumulator rail 3 is to stabilize the pressure of the fuel output by the first low-pressure oil pump 6 and the second low-pressure oil pump 11, eliminate certain fuel pressure fluctuations, and the fuel pressure output by the fuel pressure accumulator rail is more stable.

[0029] like Figure 1 and Figure 2As shown, the first low-pressure oil pump 6 and the second low-pressure oil pump 11 are both electric oil pumps. The first low-pressure oil pump 6 and the second low-pressure oil pump 11 are controlled by a controller. The first low-pressure oil pump 6 and the second low-pressure oil pump 11 are powered by the controller control relay. The power supply roller pump assembly of the first low-pressure oil pump 6 and the second low-pressure oil pump 11 rotates to generate a vacuum at the oil pump suction port, and the fuel is sucked out of the fuel tank by the oil pump. The fuel pressure sensor 2 is used to detect the fuel pressure in the fuel pressure accumulator rail 3. The output voltage value when the first low-pressure oil pump 6 and the second low-pressure oil pump 11 are normally supplied by the fuel pressure sensor 2 is calibrated to indicate the fuel pressure when the system is working normally; when the first low-pressure oil pump 6 is working and the second low-pressure oil pump 11 is not working, the detection result of the fuel pressure sensor 2 corresponds to the system fuel pressure when the first low-pressure oil pump 6 is damaged; when the second low-pressure oil pump 11 is working and the first low-pressure oil pump 6 is not working, the detection result of the fuel pressure sensor 2 corresponds to the system fuel pressure when the second low-pressure oil pump 11 is damaged. The fuel pressure sensor 2 is electrically connected to the controller. When the pumping pressure of the first low-pressure oil pump 6 and the second low-pressure oil pump 11 is too high or too low, a voltage signal can be output by the fuel pressure sensor 2 and processed by the controller analog-to-digital conversion module (analog signal is converted into digital signal). The controller records the fault code information and determines whether to issue an alarm message based on the definition of the control strategy.

[0030] like Figure 1 and Figure 2 As shown, the oil pump assembly for a piston aircraft engine of the present invention further includes a shock-absorbing pad 7 arranged inside the box body and made of soft material, and the shock-absorbing pad 7 is located between the first low-pressure oil pump 6 and the second low-pressure oil pump 11 and the box body. The shock-absorbing pad 7 plays a shock-absorbing role, and can provide sufficient protection and shock-absorbing effect to the first low-pressure oil pump 6 and the second low-pressure oil pump 11 during the flight of the aircraft.

[0031] Preferably, the shock-absorbing pad 7 is made of rubber material and is clamped between the first low-pressure oil pump 6 and the inner wall of the box. At the same time, the shock-absorbing pad 7 is also clamped between the second low-pressure oil pump 11 and the inner wall of the box. The length direction of the shock-absorbing pad 7 is parallel to the length direction of the box.

[0032] The pressure regulating valve 5 is used to make the fuel pressure flowing to the oil outlet pipe 17 within the set range. The fuel is finally output through the regulation of the pressure regulating valve 5. The pressure regulating valve 5 uses the opening of the opening and closing parts in the control valve body to adjust the flow rate of the fuel medium and control the fuel pressure. The fuel pressure output by the entire system will be stable within a certain range to meet the oil inlet pressure requirements of the high-pressure fuel system.

[0033] like Figure 1 and Figure 2As shown, preferably, the oil inlets of the first low-pressure oil pump 6 and the second low-pressure oil pump 11 are both provided with pressure relief valves 9, and the pressure relief valve 9 is connected to the fuel tank through an oil return pipe. In this way, when the pressure regulating valve 5 is abnormal or the oil pressure increases abnormally, the increased oil pressure due to the continuous oil supply of the first low-pressure oil pump 6 and the second low-pressure oil pump 11 can be relieved and returned to the oil through the pressure relief valve 9, thereby ensuring the safety of the entire system.

[0034] like Figure 1 and Figure 2 As shown, the box body includes a lower shell 8 and an upper cover 1 connected to the lower shell 8, the upper cover 1 is fixedly connected to the lower shell 8, the lower shell 8 is a rectangular shell structure with a hollow interior, the first low-pressure oil pump 6, the second low-pressure oil pump 11, the fuel accumulator rail 3 and the pressure regulating valve 5 are fixedly arranged in the lower shell 8, the upper cover 1 closes the opening of the lower shell 8, the shock-absorbing pad 7 is clamped between the first low-pressure oil pump 6 and the second low-pressure oil pump 11 and the inner wall surface of the lower shell 8, and the first low-pressure oil pump 6 and the second low-pressure oil pump 11 are fixed in the inner cavity of the lower shell 8 by oil pump clamps.

[0035] like Figure 2 As shown, the first oil inlet pipe 15 and the second oil inlet pipe 16 are connected to the fuel tank, the first wiring harness plug-in 12, the second wiring harness plug-in 18 and the wiring harness plug-in of the fuel pressure sensor 2 are reliably connected to the corresponding matching connectors of the wiring harness assembly, the return oil of the pressure regulating valve 5 is connected to the fuel tank, and the oil outlet pipe 17 is connected to the fuel fine filter. The controller controls the relays of the first low-pressure oil pump 6 and the second low-pressure oil pump 11 to be energized, and the first low-pressure oil pump 6 and the second low-pressure oil pump 11 start to work, and the first low-pressure oil pump 6 and the second low-pressure oil pump 11 pump out The fuel flows to the fuel pressure accumulator rail 3 through the first one-way valve 13 and the second one-way valve 14 respectively, and then enters the high-pressure fuel pump through the pressure regulating valve 5, the oil outlet pipe 17, the fuel fine filter and the fuel rail in turn. The controller controls the fuel rail pressure and the fuel metering valve of the high-pressure fuel pump in a closed loop, and PID regulation corrects the deviation. In theory, the oil delivery of the dual low-pressure fuel pumps working at the same time can be adjusted by the controller in a closed loop to adjust the opening of the fuel metering valve, so that the actual rail pressure of the diesel engine fuel rail reaches the target rail pressure and the fuel rail pressure remains stable.

[0036] In the event that one of the first low-pressure oil pump 6 and the second low-pressure oil pump 11 fails to work, the oil output of the other oil pump that works normally can also be adjusted to the stable high-pressure system required oil pressure through the pressure regulating valve 5. The difference in the reduced flow rate is adjusted by the controller in combination with the rail pressure sensor signal closed-loop PID to adjust the current of the high-pressure oil pump fuel metering valve, and then control the opening of the fuel metering valve to control the quantitative fuel entering the high-pressure oil pump plunger chamber for pressurization, so as to achieve the target rail pressure of the actual rail pressure of the diesel engine oil rail and keep the rail pressure of the diesel engine oil rail stable. When the fuel pressure in the fuel rail remains stable, the controller can achieve the engine performance indicators that are not affected by the abnormality of a single pump in the low-pressure fuel system through the reasonable control of the injector solenoid valve power-on time and the injection timing.

[0037] At the same time, in the case of system abnormality, the fuel pressure sensor 2 arranged on the fuel accumulator rail 3 outputs a voltage signal that is inconsistent with the calibrated normal situation. By comparing the output voltage of the fuel pressure sensor 2 with the calibrated characteristic curve of the fuel pressure, the controller can process and determine whether the system oil pressure is in an abnormal situation at this time, record the fault code and determine whether to alarm, prompt the operator of the abnormal situation, and perform maintenance or replacement in time.

[0038] The fuel pressure sensor 2 collects the oil pressure in the fuel pressure accumulator rail 3 and transmits the signal to the controller. When the controller determines that the oil pressure in the fuel pressure accumulator rail 3 is not within the set range based on the signal sent by the fuel pressure sensor 2, the controller determines that the oil pump assembly is in an abnormal state at this time, and the oil pump assembly is in a fault mode. The controller sends an alarm signal to the alarm device, and the alarm device sends a fault alarm to prompt the fault to be checked. The alarm device is located in the cockpit of the aircraft. The alarm device can be a fault alarm light or a buzzer

[0039] Therefore, the control strategy of the oil pump assembly of the present invention can ensure that when the first low-pressure oil pump 6 and the second low-pressure oil pump 11 are controlled at the same time, the output oil volume of the oil pump assembly can meet the fuel volume demand of the engine, and when any one of the first low-pressure oil pump 6 and the second low-pressure oil pump 11 is abnormal, the output oil volume of the remaining low-pressure oil pump should also meet the fuel volume demand of the engine. At the same time, the controller can record and select whether to warn the abnormal state of the oil pump through the sensor signal, so that the operator can check and further process it.

[0040] The present invention also provides a piston aircraft engine, including an oil pump assembly of the above structure. The specific structure of the oil pump assembly can be referred to Figure 1 and Figure 2 Since the piston aircraft engine of the present invention includes the oil pump assembly in the above embodiment, it has all the advantages of the above oil pump assembly.

[0041] The oil pump assembly of the above structure has the following advantages:

[0042] 1) Better maintainability and high troubleshooting efficiency. When an abnormality occurs, the component module can be directly replaced without checking the sub-components one by one;

[0043] 2) Easier product quality control: By defining modular product factory standards, it is easier for OEMs and end customers to match applications and conduct quality inspections than by defining various sub-component standards;

[0044] 3) High degree of commonality, mature oil pump assembly development, after reliability verification, can be directly transplanted and applied to different application fields;

[0045] 4) Better upgradeability: the oil pump assembly module can be upgraded in terms of performance or reliability by replacing sub-components to meet the requirements of different application fields;

[0046] 5) Higher safety. It provides a feasible solution to improve the safety of the common rail diesel engine low-pressure fuel supply system. The oil pump assembly adopts a dual low-pressure oil pump redundant design. When one low-pressure oil pump stops working, the other low-pressure oil pump can still ensure the normal operation of the common rail engine; and the fuel pressure sensor can detect and warn fault signals;

[0047] 6) Product consistency is easier to control. The relative positions of low-pressure oil pumps, oil pipes, pressure regulating valves and other sub-components are fixed in the module, making it easier to control the output characteristics and product consistency of the oil pump assembly compared with the scattered arrangement of sub-components. The pressure regulating valve designed in the oil pump assembly can make the output of the oil pump assembly stable. The fuel parameters output by the oil pump assembly to the inlet of the engine's high-pressure fuel system are therefore more controllable, and the matching calibration of the high and low pressure fuel systems is better;

[0048] 7) Higher protection: The key components of the low-pressure fuel system are protected by the housing and shock-absorbing pads to form an oil pump assembly, which can effectively prevent the key components from being affected by corrosion, vibration and electromagnetic interference;

[0049] 8) The oil pump assembly has the ability to maintain operation under abnormal system oil pressure conditions. The pressure relief valve designed in the oil pump assembly can ensure that when the system oil pressure rises abnormally, the excessive fuel pressure can be relieved through the pressure relief valve and maintained at a relatively safe and stable low-pressure system oil pressure. Under this oil pressure, the fuel pressure sensor can detect and warn of fault signals. At the same time, the engine can also maintain operation under this extreme state and be taken to the maintenance site for inspection and maintenance.

[0050] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. An oil pump assembly applicable to a piston aircraft engine, comprising a first low-pressure oil pump and a second low-pressure oil pump, characterized in that: The invention also includes a casing, a first one-way valve connected to the oil outlet of the first low-pressure oil pump, a second one-way valve connected to the oil outlet of the second low-pressure oil pump, a fuel pressure accumulator rail connected to the first one-way valve and the second one-way valve, a fuel pressure sensor arranged on the fuel pressure accumulator rail, and a pressure regulating valve connected to the oil outlet of the fuel pressure accumulator rail. The fuel pressure accumulator rail, the first low-pressure oil pump, the second low-pressure oil pump, the first one-way valve, the second one-way valve and the pressure regulating valve are arranged inside the casing.

2. The oil pump assembly suitable for a piston aircraft engine according to claim 1, characterized in that: The first low-pressure oil pump and the second low-pressure oil pump are arranged side by side inside the box, and the first low-pressure oil pump and the second low-pressure oil pump are located on the same side of the fuel pressure accumulator rail.

3. The oil pump assembly suitable for a piston aircraft engine according to claim 2, characterized in that: The first low-pressure oil pump, the second low-pressure oil pump and the pressure regulating valve are located on the same side of the fuel pressure accumulator rail, and the first low-pressure oil pump is located between the second low-pressure oil pump and the pressure regulating valve.

4. The oil pump assembly for a piston aircraft engine according to any one of claims 1 to 3, characterized in that: When the first low-pressure fuel pump is working and the second low-pressure fuel pump is not working, the detection result of the fuel pressure sensor corresponds to the system fuel pressure when the first low-pressure fuel pump is damaged.

5. The oil pump assembly for a piston aircraft engine according to any one of claims 1 to 3, characterized in that: It also includes a shock-absorbing pad which is arranged inside the box and is made of soft material. The shock-absorbing pad is located between the first low-pressure oil pump, the second low-pressure oil pump and the box.

6. The oil pump assembly suitable for a piston aircraft engine according to claim 5, characterized in that: The shock-absorbing pad is made of rubber material.

7. The oil pump assembly suitable for a piston aircraft engine according to any one of claims 1 to 3, characterized in that: The oil inlets of the first low-pressure oil pump and the second low-pressure oil pump are both provided with pressure relief valves.

8. The oil pump assembly for a piston aircraft engine according to any one of claims 1 to 3, characterized in that: The box body comprises a lower shell and an upper cover connected with the lower shell.

9. A piston aircraft engine, characterized in that: Comprising the oil pump assembly as described in any one of claims 1 to 8.

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