An eVTOL aircraft lift electric drive cooling system

Abstract

The application discloses an eVTOL aircraft lift electric drive cooling system, which comprises a motor arm, a motor arm front fairing connected to the front end of the motor arm, a heat dissipation water tank connected below the motor arm front fairing, a controller and a lift motor connected to the rear end of the heat dissipation water tank through a liquid cooling assembly, wherein the lift motor and the controller are installed in the interior of the motor arm, the heat dissipation water tank adopts a conformal structure with the motor arm, and the outer surface of the heat dissipation water tank is of a curved surface structure. The system adopts a radiator integrated with the structure of the motor arm, so that the radiator does not need to be arranged outside the aircraft structure, and a cooling air duct is not needed, thereby reducing the resistance of the aircraft. The integrated heat dissipation water tank is cooled by external airflow, and the cooling requirement of the aircraft is met at an acceptable cost.

Description

Technical Field

[0001] This invention relates to the field of aviation technology, and more specifically to an eVTOL aircraft lift electric drive cooling system. Background Technology

[0002] The development of eVTOL (Electric Vertical Takeoff and Landing) aircraft has attracted widespread attention from aerospace companies, the automotive industry, and the transportation industry. Potential applications of eVTOL include urban passenger transport, regional passenger transport, freight transport, personal aircraft, and emergency medical services, among other scenarios. Compound wings are one of the important configuration forms for eVTOL aircraft (see typical eVTOL compound wing configurations). Figure 1 The compound wing propulsion system comprises a lift system and a thrust system. Typically, the lift system provides lift only during the vertical takeoff and landing (VTOL) and transition phases, while the thrust system provides forward propulsion during cruise flight. The compound wing employs a hybrid wing configuration combining a fixed wing and a multirotor, integrating the advantages of multirotor VTOL and the long cruise time, high speed, and long distance of a fixed-wing aircraft. The lift system of the compound wing includes motors, controllers, propellers, and related components. The lift system operates only during the vertical takeoff, landing, and hovering phases of the eVTOL aircraft. However, the power requirements during these phases are high. Simultaneously, due to the efficiency factors of the motors and controllers, the electric drive (motors and controllers) generates a significant amount of heat, with 5%–15% of the electrical energy released as heat. Furthermore, the core components of the motors and controllers may malfunction or fail under the influence of accumulated heat. In addition, for the permanent magnet synchronous motors that are commonly used, the permanent magnets of the motor will demagnetize at a certain temperature (about 170°C). A safety boundary must be reserved during use. The core components that perform the inversion in the controller are also usually limited by temperature. The heat flux density of the core components of the high-power motor controller is concentrated. Therefore, the core components of the controller and the motor must be cooled. How to effectively cool the electric drive system of the lift system is the guarantee for the normal operation of the eVTOL aircraft power system.

[0003] Existing technologies primarily employ traditional air-cooling or liquid-cooling systems to cool the lift system. However, both methods present several challenges: air-cooling typically requires cooling ducts to introduce relatively cool air into the components or their mounting locations, removing heat through natural or forced airflow. Air-cooling suffers from poor heat dissipation capacity, usually only capable of handling low-power cooling. Furthermore, the inlet and outlet of the cooling ducts disrupt the aircraft's aerodynamic shape, and complex flow fields and various environmental conditions must be considered, making system matching difficult.

[0004] Liquid cooling is highly efficient. Through liquid circulation, heat from the components being cooled is transferred to the coolant, which then circulates to transfer heat to an "air-fluid" radiator located externally on the aircraft or within the cooling duct. The radiator then transfers the heat to the outside air. While liquid cooling systems offer high heat exchange efficiency—with convective heat transfer coefficients typically 20 to 100 times that of air radiators—their layout and construction are more complex, resulting in greater weight. Furthermore, the placement of external radiators or the inlet / outlet of the cooling duct can disrupt the aircraft's aerodynamic shape, increasing drag.

[0005] Therefore, there is an urgent need for an aircraft lift electric drive cooling system that has strong heat dissipation capabilities, meets the requirements, is lightweight, and does not damage the aircraft's aerodynamic shape to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide an eVTOL aircraft lift electric drive cooling system to solve the problems mentioned in the background art. To achieve the above objective, this invention provides the following technical solution: an eVTOL aircraft lift electric drive cooling system, including a motor arm, the front end of which is connected to a front fairing, a heat sink connected below the front fairing, and the rear end of the heat sink connected to a controller and a lift motor via a liquid cooling assembly. The lift motor and controller are installed inside the motor arm, the shape of the heat sink conforms to the shape of the motor arm, and the outer surface of the heat sink is curved.

[0007] Preferably, the rear end of the heat dissipation tank is connected to a water tank inlet pipe and a water tank outlet pipe, the upper end of the heat dissipation tank is equipped with a water tank filling port and a water tank vent valve, the water tank filling port is equipped with a water tank filling port cover, and the heat dissipation tank is composed of an outer surface and an inner surface through two layers of curved surfaces.

[0008] Preferably, the liquid cooling assembly includes a liquid cooling pump, the liquid cooling pump is connected to the water tank outlet pipe and the controller inlet pipe, the controller inlet pipe is connected to the controller, the controller is connected to the controller outlet pipe, the controller outlet pipe is connected to the water tank inlet pipe, the controller integrates a liquid cooling plate, and the controller outlet pipe and the controller outlet pipe are connected to the liquid cooling plate.

[0009] Preferably, the liquid cooling assembly includes a liquid cooling pump, which is connected to the water tank outlet pipe and the controller inlet pipe. The controller inlet pipe is connected to the controller, the controller is connected to the motor inlet pipe, the motor inlet pipe is connected to the lift motor, and the lift motor is connected to the water tank inlet pipe through the motor outlet pipe. The controller has an integrated liquid cooling plate, and the lift motor has a liquid cooling channel inside. The liquid cooling plate is connected to the controller inlet pipe and the motor inlet pipe.

[0010] Preferably, the upper end of the cooling water tank is provided with an upper docking surface, the water tank filling port and the water tank vent valve are installed on the upper docking surface, the upper docking surface of the water tank is connected to the lower bottom surface of the front screed of the motor arm, the front end of the motor arm is provided with a structural docking surface, and the rear end of the cooling water tank is provided with an inner mounting surface, the structural docking surface is connected to the inner mounting surface of the water tank.

[0011] The technical effects and advantages of this invention are as follows: It meets the heat dissipation requirements of the lift electric drive: This system meets the heat dissipation requirements of the lift motor and its controller in a stable and reliable way, overcomes the problem of low air cooling efficiency, is less affected by the environment, especially high temperature, and can meet the requirements of eVTOL aircraft vertical take-off and landing in hot weather.

[0012] The problem of liquid cooling system radiators being unable to accept incoming airflow cooling was solved: a radiator integrated with the motor arm structure was adopted, eliminating the need for external radiator placement and cooling air ducts, thus reducing aircraft drag. The integrated radiator tank accepts external incoming airflow cooling, meeting the aircraft's cooling requirements at an acceptable cost;

[0013] The complexity of the aircraft's power cooling system has been reduced, and heat dissipation efficiency has been improved: the water tank, designed integrally with the structure, serves as a radiator and simultaneously acts as a flight structure to ensure the aircraft's aerodynamic shape. It combines three functions in one. The elimination of a separate water tank improves structural efficiency and reduces aircraft weight. The outer wall of the water tank, acting as the surface of the radiator, can withstand the high-speed airflow during forward flight, efficiently meeting the heat dissipation requirements of the lift system at minimal cost. Attached Figure Description

[0014] Figure 1 This is an isometric view of the installation of the present invention;

[0015] Figure 2 This is an isometric view of the cooling water tank of the present invention;

[0016] Figure 3 This is an isometric view of the installation of the cooling water tank and the motor arm of the present invention;

[0017] Figure 4 This is an axonometric view of the eVTOL aircraft lift electric drive cooling system in Example 1;

[0018] Figure 5 This is an axonometric view of the eVTOL aircraft lift electric drive cooling system in Example 2.

[0019] In the diagram: 1. Motor arm; 3. Front fairing of motor arm; 4. Lift motor; 5. Lift propeller; 6. Cooling water tank; 7. Liquid cooling pump; 8. Controller inlet pipe; 9. Controller; 10. Controller outlet pipe; 15. Motor inlet pipe; 16. Motor outlet pipe; 20. Water tank outlet pipe; 21. Water tank inlet pipe; 22. Water tank filling port; 23. Water tank filling port cover; 24. Water tank vent valve; 25. Water tank heat dissipation outer surface; 26. Water tank inner surface; 27. Water tank inner mounting surface; 30. Water tank upper mating surface; 31. Structural mating surface. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention will be further described below with reference to specific illustrations. In the description of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "connection" should be interpreted broadly. For example, they can be fixed connections, detachable connections, integral connections, mechanical connections, or electrical connections; they can be direct connections or indirect connections through an intermediate medium; and they can be internal connections between two components.

[0021] Example 1

[0022] like Figures 1-4 As shown, the eVTOL aircraft lift electric drive cooling system includes a radiator 6, which is installed at the lower front end of the motor arm 1. The radiator 6 is connected to the front fairing 3 of the motor arm, which is connected to the motor arm 1. The rear end of the radiator 6 is connected to a water tank inlet pipe 21 and a water tank outlet pipe 20. The water tank outlet pipe 20 is connected to a liquid cooling pump 7. The liquid cooling pump 7 is connected to the liquid cooling plate integrated inside the controller 9 through the controller inlet pipe 8. The liquid cooling plate is connected to the water tank inlet pipe 21 through the controller outlet pipe 10. When cooling the controller 9, the coolant inside the radiator 6 is sent to the liquid cooling plate at the bottom of the controller 9 through the liquid cooling pump 7, transferring the heat from the inverter and other heat-generating components inside the controller 9 to the liquid cooling system. The coolant circulates back into the radiator 6, and the heat absorbed by the coolant raises the temperature of the coolant inside the radiator 6, which is then dissipated through the temperature difference with the environment.

[0023] The shape of the radiator 6 is conformally designed to fit the motor arm 1. The outer wall of the radiator 6 also serves as the aircraft structure, with an outer surface that is a curved surface with good aerodynamic characteristics, ensuring acceptable drag during forward flight. The radiator 6 is made of a thermally conductive metal material, such as aluminum alloy or an alloy with even better thermal conductivity. The outer wall of the radiator 6 has low thermal resistance, allowing heat to be dissipated to the external environment through thermal conduction. The structure of the radiator 6 maximizes its cooling area by using two layers of curved surfaces to form the outer surface 25 and the inner surface 26 of the radiator 6. At the same time, the thickness of the radiator 6 is reduced to ensure a relatively large outer surface for a given volume. The radiator 6 is equipped with a radiator filler port 22, which is fitted with a radiator filler cap 23. The radiator filler port 22 allows for easy filling with the desired amount of coolant. The upper part of the radiator has a radiator vent valve 24 to ensure pressure balance between the radiator 6 and the external environment without coolant leakage.

[0024] The capacity of the cooling water tank 6 is determined based on the required heat dissipation volume and capacity of the flight profile. The greater the heat dissipation volume and the worse the heat dissipation capacity, the larger the volume of the cooling water tank 6 needs to be, and the larger its front surface area is required. Where conditions permit, through design trade-offs, such as reducing the thickness of the cooling water tank 6 and maximizing the area of ​​its outer surface heat dissipation surface, the cooling water tank 6 has an upper docking surface 30, the front end of the motor arm 1 has a structural docking surface 31, and the rear end of the cooling water tank 6 has an inner mounting surface 27. The structural docking surface 31 and the inner mounting surface 27 are correspondingly connected, thereby ensuring a reliable connection between the cooling water tank 6 and the load-bearing structure of the motor arm 1, while also ensuring good fit with the motor arm 1.

[0025] The installation, structure, and operation of the radiator 6 mounted at the front end of the motor arm 1 meet the cooling requirements of the lift electric drive system for vertical takeoff and landing (VTOL) aircraft. The lift system primarily supports the aircraft's vertical takeoff and landing. During vertical takeoff, the lift system operates at high power, and the liquid cooling system maintains the controller inverter components at a reasonable temperature. Simultaneously, the coolant absorbs heat and its temperature rises, but does not exceed operating limits. When the aircraft transitions to forward flight and cruise flight, the frontal airflow directly cools the outer wall of the radiator 6, making it a liquid-air heat exchanger. The radiator 6 has a relatively large outer surface area, and given the aircraft's relatively high forward flight speed (typically reaching approximately 200 km / h), the radiator 6 provides ideal heat dissipation. Through heat dissipation during the cruise phase (a few minutes to tens of minutes), the temperature of the coolant in the radiator 6 is reduced to a lower initial temperature. When the aircraft needs to reverse course until landing, it can meet the heat storage requirements during the landing phase, compared to traditional liquid cooling systems. No dedicated liquid-air radiator is required; it fully utilizes the frontal airflow for cooling during forward flight. The radiator tank simultaneously holds coolant and functions as a radiator.

[0026] Example 2

[0027] like Figure 1-3 and Figure 5 As shown, the eVTOL aircraft lift electric drive cooling system includes a radiator 6, which is installed at the lower front end of the motor arm 1. The radiator 6 is connected to the front fairing 3 of the motor arm, which is connected to the motor arm 1. The rear end of the radiator 6 is connected to a water tank inlet pipe 21 and a water tank outlet pipe 20. The water tank outlet pipe 20 is connected to a liquid cooling pump 7. The liquid cooling pump 7 is connected to the liquid cooling plate integrated inside the controller 9 through the controller inlet pipe 8. The liquid cooling plate is connected to the liquid cooling channel inside the lift motor 4 through the motor inlet pipe 15. The liquid cooling channel is connected to the water tank inlet pipe 21 through the motor outlet pipe 16. The lift motor 4 is connected to the lift propeller 5 to provide power. The cooling system uses a series connection to cool the controller 9 and the lift motor 4 simultaneously. The coolant flows out of the radiator 6, is pressurized by the liquid cooling pump 7, and enters the liquid cooling plate inside the controller 9. After absorbing the heat from the liquid cooling plate, it enters the liquid cooling channel inside the lift motor 4 through the motor inlet pipe 15. After cooling the internal windings of the lift motor 4, the coolant returns to the radiator tank 6 via the motor outlet pipe 16. The capacity and flow rate of the liquid cooling system need to be carefully balanced to meet overall heat exchange requirements and weight limitations.

[0028] After the coolant flows out of controller 9, its temperature rises. Under various operating conditions, the temperature of the coolant flowing out of controller 9 needs to meet the temperature requirements of the inlet of the liquid cooling channel inside the lift motor 4. Typically, the lift motor 4 operates at a high temperature, allowing for a higher coolant temperature. Therefore, connecting controller 9 and lift motor 4 in series for cooling is naturally feasible. Through reasonable selection of capacity and flow rate, and optimized design of the internal heat dissipation channel, the requirements for both controller 9 and lift motor 4 can be met simultaneously.

[0029] The shape of the radiator 6 is conformally designed to fit the motor arm 1. The outer wall of the radiator 6 also serves as the aircraft structure, with an outer surface that is a curved surface with good aerodynamic characteristics, ensuring acceptable drag during forward flight. The radiator 6 is made of a thermally conductive metal material, such as aluminum alloy or an alloy with even better thermal conductivity. The outer wall of the radiator 6 has low thermal resistance, allowing heat to be dissipated to the external environment through thermal conduction. The structure of the radiator 6 maximizes its cooling area by using two layers of curved surfaces to form the outer surface 25 and the inner surface 26 of the radiator 6. At the same time, the thickness of the radiator 6 is reduced to ensure a relatively large outer surface for a given volume. The radiator 6 is equipped with a radiator filler port 22, which is fitted with a radiator filler cap 23. The radiator filler port 22 allows for easy filling with the desired amount of coolant. The upper part of the radiator has a radiator vent valve 24 to ensure pressure balance between the radiator 6 and the external environment without coolant leakage.

[0030] The capacity of the cooling water tank 6 is determined based on the required heat dissipation volume and capacity of the flight profile. The greater the heat dissipation volume and the worse the heat dissipation capacity, the larger the volume of the cooling water tank 6 needs to be, and the larger the surface area of ​​its front portion is required. Where conditions permit, through design trade-offs, such as reducing the thickness of the cooling water tank 6 and maximizing the area of ​​its outer surface heat dissipation surface, the cooling water tank 6 is provided with an upper docking surface 30, and the front end of the motor arm 1 is provided with a structural docking surface 31. This ensures a reliable connection between the cooling water tank 6 and the load-bearing structure of the motor arm 1, while also ensuring good fit between them.

[0031] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An eVTOL aircraft lift electric drive cooling system, comprising a motor arm, characterized in that: The front end of the motor arm is connected to the front fairing of the motor arm, and a heat dissipation tank is connected below the front fairing of the motor arm. The rear end of the heat dissipation tank is connected to the controller and the lifting motor through a liquid cooling component. The lifting motor and the controller are installed inside the motor arm. The shape of the heat dissipation tank is conformal to the shape of the motor arm, and the outer surface of the heat dissipation tank is a curved structure. The liquid cooling assembly includes a liquid cooling pump, which is connected to the water tank outlet pipe and the controller inlet pipe. The controller inlet pipe is connected to the controller, the controller is connected to the motor inlet pipe, the motor inlet pipe is connected to the lift motor, and the lift motor is connected to the water tank inlet pipe through the motor outlet pipe. The controller integrates a liquid cooling plate, and the lift motor has a liquid cooling channel inside. The liquid cooling plate is connected to the controller inlet pipe and the motor inlet pipe. The cooling system uses a series connection to cool the controller and the lift motor simultaneously. The upper end of the cooling water tank is provided with a water tank upper docking surface. A water tank filling port and a water tank vent valve are installed on the water tank upper docking surface. The water tank upper docking surface is connected to the lower bottom surface of the front fairing of the motor arm. The front end of the motor arm is provided with a structural docking surface. The structural docking surface is connected to the rear end of the cooling water tank, ensuring a reliable connection between the cooling water tank and the load-bearing structure of the motor arm. The outer wall of the cooling water tank also serves as the aircraft structure.

2. The eVTOL aircraft lift electric drive cooling system according to claim 1, characterized in that: The water tank inlet pipe and water tank outlet pipe are connected to the rear end of the cooling water tank. A water tank filling port cover is installed on the water tank filling port. The cooling water tank has an outer surface for heat dissipation and an inner surface for heat dissipation through two layers of curved surfaces.

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