Aircraft thermal management system and control method

Abstract

The invention belongs to the technical field of aircraft thermal management, and discloses an aircraft thermal management system and a control method, the system comprises an evaporation circulation refrigeration loop, a liquid cooling circulation loop, a power battery, a motor control box and a motor; an in-cabin evaporator of the evaporation circulation refrigeration loop and an in-cabin radiator of the liquid cooling circulation loop are arranged in the same air duct, and the liquid cooling circulation loop flows through the power battery, the motor control box and the motor and dissipates heat for the power battery, the motor control box and the motor; an evaporation fan is arranged in the air duct.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft thermal management, and in particular relates to an aircraft thermal management system and a control method. Background Art

[0002] The entire flight process of an electric-driven vertical take-off and landing aircraft mainly relies on power batteries to provide power. Especially during take-off and landing, the output power of the rotor drive motor is close to 10 times that of cruising, and the discharge rate of the power battery is greatly increased. At this time, the power battery, motor control box and motor all have a sharp increase in internal temperature due to the huge output power, which in turn affects the performance and life of the power battery, motor control box and motor, and even causes safety accidents. Therefore, for electric-driven vertical take-off and landing aircraft, the improvement of thermal management technology is becoming increasingly important.

[0003] Traditional aircraft thermal management technologies mainly include forced air cooling, traditional liquid cooling, heat pipe cooling, microchannel cooling, phase change material heat storage, etc. According to the flight characteristics of electric drive vertical take-off and landing aircraft, the short-term heat generation power of power batteries, motor control boxes and motors is much greater than the heat generation power of conventional electronic equipment. At the same time, due to the current power battery capacity density and system weight, a single thermal management technology can no longer meet the requirements, and composite thermal management technology has gradually become a research hotspot. Summary of the invention

[0004] Purpose of the invention: To provide an aircraft thermal management system and control method, which can provide a comfortable riding environment for the occupants while meeting the heat dissipation requirements of the power battery, motor control box and motor.

[0005] In order to solve the above technical solutions,

[0006] An aircraft thermal management system includes an evaporative cycle refrigeration loop, a liquid cooling cycle loop, a power battery, a motor control box and a motor;

[0007] The cabin evaporator of the evaporative cycle refrigeration and the cabin radiator of the liquid cooling cycle loop are arranged in the same air duct, and the liquid cooling cycle loop flows through the power battery, the motor control box and the motor to dissipate heat for them;

[0008] An evaporating fan is arranged in the air duct.

[0009] Further, the evaporative cycle refrigeration includes: a compressor, a condenser, a condensing fan and an evaporator in the cabin;

[0010] The left end of the cabin evaporator is connected to the compressor, the condenser, the first electronic expansion valve and the right end of the cabin evaporator in sequence through pipelines;

[0011] The condensing fan dissipates heat for the condenser.

[0012] Furthermore, the liquid cooling circulation loop includes: the right end of the cabin radiator, a liquid storage tank, a liquid cooling evaporator, a boost pump, a heating joint, a power battery, a motor control box, a motor and the left end of the cabin radiator which are connected in sequence through pipelines.

[0013] Furthermore, a first three-way valve is provided at the outlet of the liquid cooling circuit of the power battery, and a second three-way valve is provided at the left end of the radiator in the cabin;

[0014] Port 1A of the first three-way valve is connected to the outlet of the power battery liquid cooling circuit, port 1B of the first three-way valve is connected to port 2A of the second three-way valve through a pipeline, and port 1C of the first three-way valve is connected to the inlet of the motor cooling unit; the outlet of the motor cooling unit is connected to port 2B of the second three-way valve, and port 2C of the second three-way valve is connected to the left end of the radiator in the cabin.

[0015] Furthermore, the motor heat dissipation unit includes two parallel branches, each branch includes a motor and a motor control box.

[0016] Furthermore, a switching valve is provided between the outlet of the motor cooling unit and the 2B port of the second three-way valve, and the switching valve is connected in parallel with the skin radiator.

[0017] Furthermore, a third three-way valve is provided on the pipeline between port 1B of the first three-way valve and port 2A of the second three-way valve, port 3A of the third three-way valve is connected to port 1B of the first three-way valve, port 3B of the third three-way valve is connected to port 2A of the second three-way valve, and port 3C of the third three-way valve is connected to the right end of the radiator in the cabin.

[0018] Furthermore, the liquid-cooled evaporator is connected between the liquid storage tank and the boost pump, the cabin radiator is connected between the skin radiator and the liquid storage tank, and a second electronic expansion valve is provided between the liquid-cooled evaporator and the condenser.

[0019] A method for controlling an aircraft thermal management system, comprising:

[0020] Method 1: Close the second electronic expansion valve, and start the evaporator fan, condenser fan, first electronic expansion valve and compressor in sequence to cool the cabin;

[0021] Method 2: The liquid cooling circulation loop is open, and the first three-way valve and the third three-way valve are adjusted so that the outlet of the power battery liquid cooling loop is directly connected to the liquid storage tank, so as to cool only the power battery;

[0022] Method 3: The liquid cooling circulation loop is turned on, and the first, second, and third three-way valves are adjusted, and the switching valve is opened so that the outlet of the power battery liquid cooling loop is directly connected to the liquid storage tank, and at the same time, the outlet of the power battery liquid cooling loop is connected to the motor cooling unit and then directly connected to the liquid storage tank;

[0023] Method 4: Switch the valve to close based on method 3.

[0024] Furthermore, when in the ground state, a ground heating device is connected via a heating joint.

[0025] In summary, the beneficial effects of the present invention are as follows:

[0026] 1. In the liquid cooling circulation loop of the present invention, the low-temperature coolant sequentially enters the power battery, the motor control box and the motor, realizing the step-by-step heat dissipation of the coolant, improving the heat dissipation efficiency of the coolant, and also improving the heat dissipation efficiency of the skin radiator, thereby reducing the weight and power consumption of the system;

[0027] 2. The combination of the liquid cooling circulation loop and the evaporative circulation refrigeration loop in the present invention reduces the temperature of the coolant in the liquid cooling circulation loop while making the temperature control of the power battery, the motor control box and the motor more flexible. By adjusting the compressor speed and the flow rate of the refrigerant, the differentiated heat dissipation requirements of different components are achieved;

[0028] 3. The combination of the liquid cooling circulation loop and the evaporative circulation refrigeration loop in the present invention can significantly improve the riding environment of the cabin personnel, enhance the comfort of the cabin passengers, and reduce the onboard power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Working principle diagram of thermal management system when dissipating heat;

[0030] Figure 2 Working principle diagram of thermal management system when heating the floor;

[0031] 1- compressor; 2- condenser; 3- condensing fan; 4- first electronic expansion valve; 5- liquid-cooled evaporator; 6- second electronic expansion valve; 7- cabin evaporator; 8- evaporating fan; 9- air duct; 10- boost pump; 11- heating connector; 12- first temperature and pressure sensor; 13- flow sensor; 14- power battery; 15- first motor control box; 16- second motor control box; 17- first motor; 18- second motor; 19- skin radiator; 20- rotor; 21- first three-way valve; 22- switching valve; 23- second three-way valve; 24- third three-way valve; 25- second temperature and pressure sensor; 26- cabin radiator; 27- liquid storage tank; 28- ground heating device. DETAILED DESCRIPTION

[0032] 1) A thermal management system combining an evaporative cycle refrigeration circuit, a liquid cooling cycle circuit and a skin radiator, such as Figure 1 As shown. The liquid cooling circulation loop consists of a booster pump, a cabin radiator, a liquid storage tank, a flow sensor, a temperature sensor, a switching valve, a three-way valve and liquid cooling pipelines. The evaporative cycle refrigeration loop consists of a compressor, a condenser, an electronic expansion valve, a liquid cooling evaporator, a cabin evaporator, a refrigerant pipeline, etc. The skin radiator consists of a wing skin flow channel and a rotor.

[0033] 2) In the above scheme, the evaporative cycle refrigeration circuit includes a liquid-cooled evaporator and an in-cabin evaporator. The two evaporators are connected in parallel in the evaporative cycle refrigeration circuit and are both equipped with electronic expansion valves. The evaporation temperature of the corresponding evaporator is controlled by adjusting the opening of the electronic expansion valve.

[0034] 3) In the above scheme, the liquid-cooled evaporator is used to cool the high-temperature coolant flowing into the liquid-cooled circulation loop, and the cabin evaporator is used to cool the cabin personnel to provide a comfortable riding environment for the cabin personnel. The two evaporators do not interfere with each other;

[0035] 4) In the above scheme, the compressor speed of the evaporative cycle refrigeration loop is adjustable, and the compressor speed is adjusted by monitoring the temperature of the coolant at both ends of the heat-generating device in the liquid cooling cycle loop, so as to match the cooling capacity of the evaporative cycle refrigeration loop with the heat dissipation of the liquid cooling cycle loop, thereby improving system reliability and saving on-board power consumption.

[0036] 5) In the above scheme, the liquid cooling pipeline of the liquid cooling circulation loop connects the power battery, the motor control box and the motor in series in the system. The low-temperature coolant first flows into the power battery for heat dissipation, and then flows into the motor control box and the motor for heat dissipation. Because the power battery has a temperature resistance of less than 45°C, the motor control box has a temperature resistance of less than 120°C, and the motor has a temperature resistance of less than 180°C, this connection method can prevent the temperature of the coolant flowing into the power battery from overheating, and at the same time achieve step-by-step heat dissipation;

[0037] 6) In the above scheme, a first three-way valve is provided on the liquid cooling pipeline between the power battery and the motor control box and the motor. After the coolant passes through the power battery, part of the coolant flows back to the liquid storage tank through the first three-way valve and the third three-way valve, and the rest enters the motor control box and the motor to continue to dissipate heat. By controlling the flow rate of this part of the coolant, the coolant temperature at the motor outlet can be increased as much as possible while meeting the heat dissipation of the motor control box and the motor. When the high-temperature coolant flows into the skin radiator, due to the large temperature difference between the coolant and the outside atmosphere, the heat dissipation power of the skin radiator can be greatly improved to reduce the heat dissipation pressure of the radiator and the liquid-cooled evaporator in the rear cabin.

[0038] 7) In the above scheme, the skin radiator uses the downwash airflow of the rotor to dissipate the heat of the coolant in the flow channel. When the electric-driven vertical take-off and landing aircraft takes off and lands, the rotor is in the rotor downwash mode, and there is no forward flight ramjet airflow. At this time, the power battery, motor control box and motor simultaneously enter the high-power heating stage, and the skin radiator can make full use of the downwash airflow provided by the rotor for heat dissipation.

[0039] 8) In the above scheme, the cabin radiator set in the liquid cooling circulation loop is connected in series with the cabin evaporator of the evaporative circulation refrigeration loop, and the cabin radiator and the cabin evaporator share a fan. When the system dissipates heat, the cabin air first precools the coolant in the liquid cooling circulation loop, and the higher temperature air passing through the cabin radiator is cooled in the cabin evaporator before being used to cool the cabin personnel.

[0040] 9) In the above scheme, three three-way valves are set in the liquid cooling circulation loop, and an electronic expansion valve is set in the evaporative cycle refrigeration loop. When the system dissipates heat, the control system sends instructions to adjust the states of the three-way valve and the electronic expansion valve, and changes the flow direction of the coolant and the refrigerant, thereby realizing different heat dissipation modes, including a heat dissipation mode for the power battery only, a heat dissipation mode for the cabin personnel only, a heat dissipation mode for the power battery and the cabin personnel at the same time, and a heat dissipation mode for the cabin personnel, power battery, motor control box and motor at the same time.

[0041] 10) In the above scheme, a heating joint is provided in the liquid cooling circulation loop. When the power battery and the personnel in the cabin need to be heated on the ground, the ground heating device is connected to the heating joint. After the coolant is heated by the ground heating device, the high-temperature coolant first flows into the power battery for heating, and then heats the personnel in the cabin through the radiator in the cabin.

[0042] 11) In the above scheme, the liquid cooling circulation loop can achieve heating of the cabin personnel during flight by connecting the power battery, motor control box and motor in series. When the cabin needs to be heated during flight, the coolant flow entering the motor control box and the motor is controlled to maximize the coolant temperature while satisfying the heat dissipation of the motor control box and the motor. When the switching valve is opened, the high-temperature coolant bypasses the skin radiator and directly enters the cabin radiator, which heats the cabin personnel.

[0043] 12) In the above scheme, when the thermal management system is heating, the control system sends instructions to set the state of the regulating valve, which can change the flow direction of the coolant, thereby realizing different heating modes, including a power battery heating mode only and a power battery and cabin personnel heating mode at the same time.

[0044] Embodiment 1, aerial work

[0045] The thermal management system of the electric drive vertical take-off and landing aircraft during flight includes a cooling mode for cabin personnel only, a cooling mode for the power battery only, a cooling mode for both the power battery and cabin personnel at the same time, a cooling mode for cabin personnel, power battery, motor control box and motor at the same time, and a heating mode for cabin personnel only, as shown in 1.

[0046] When only the people in the cabin are in cooling mode, the control system sends a command to first close the second electronic expansion valve 6, and then start the evaporating fan 8, the condensing fan 3, the first electronic expansion valve 4 and the compressor 1 in sequence. At this time, the required cooling capacity is small, the compressor 1 runs at a low speed, and the evaporating fan 8 draws air from the cabin to cool it through the evaporator 7 in the cabin, and then provides cool air for the people in the cabin through the air duct 9.

[0047] When only the power battery heat dissipation mode is used, first, the control system sends a command to start the liquid cooling circulation loop, adjust the first three-way valve 21, the second three-way valve 23 and the third three-way valve 24, so that only the 1A port and the 1B port of the first three-way valve 21 are opened, the valve ports of the second three-way valve 23 are all closed, and only the 3A port and the 3C port of the third three-way valve 24 are opened, and then the boost pump 10 is started to drive the coolant to flow; secondly, the evaporative cycle refrigeration loop is started, the first electronic expansion valve 4 is closed, and then the condensing fan 3, the second electronic expansion valve 6 and the compressor 1 are started in sequence. At this time, the required cooling capacity is relatively large, and the compressor 1 runs at medium speed. The refrigerant in the liquid-cooled evaporator 5 changes phase to cool the coolant, and the cooled coolant then dissipates heat to the power battery.

[0048] When the power battery and the cabin personnel are in the heat dissipation mode at the same time, first, the control system sends a command to start the liquid cooling circulation loop, adjust the first three-way valve 21, the second three-way valve 23 and the third three-way valve 24, so that only the 1A port and the 1B port of the first three-way valve 21 are opened, the valve ports of the second three-way valve 23 are all closed, and only the 3A port and the 3C port of the third three-way valve 24 are opened, and then the boost pump 10 is started, and the coolant passing through the liquid cooling evaporator 5 first cools the power battery 14, and then flows back to the liquid storage tank 27 through the first three-way valve 21 and the third three-way valve 24; secondly, the evaporation cycle refrigeration loop is started, and the condensing fan 3, the evaporating fan 8, the second electronic expansion valve 6, the first electronic expansion valve 4 and the compressor 1 are started in sequence. At this time, the required cooling capacity is large, and the compressor 1 runs at a high speed. The refrigerant in the liquid cooling evaporator 5 changes phase to cool the coolant, and the evaporating fan 8 draws the cabin air to cool it through the cabin evaporator 7, and then provides cool air for the cabin personnel through the air duct 9.

[0049] When the cabin personnel, power batteries, motor control box and motor are in cooling mode at the same time. First, start the liquid cooling circulation loop, adjust the first three-way valve 21, the second three-way valve 23 and the third three-way valve 24, so that the valve ports of the first three-way valve 21 are all open, the valve ports of the second three-way valve 23 are all open, and only the 3A port and the 3B port of the third three-way valve 24 are open, close the switching valve 22, and then start the boost pump 10. The coolant passing through the liquid cooling evaporator 5 first cools the power battery 14. By controlling the opening of the first three-way valve 211C port and the 1B port, part of the coolant flows into the cabin radiator 26 through the third three-way valve 24 and the second three-way valve 23, and the rest enters the first motor control box 15, the second motor control box 16, the first motor 17 and the second motor 18 for heat dissipation. By controlling the flow rate of this part of the coolant, it can meet the motor While the control box and the motor are dissipating heat, the temperature of the coolant at the motor outlet is increased as much as possible. When the coolant flows into the skin radiator 19, due to the large temperature difference between the coolant and the outside atmosphere at this location, the downwash airflow of the rotor 20 can be used to greatly improve the heat dissipation efficiency of the skin radiator 19. The coolant after heat dissipation flows into the radiator 26 in the cabin for pre-cooling, and finally flows back to the liquid storage tank 27 for recirculation; secondly, the evaporative cycle refrigeration circuit is started, and the condensing fan 3, the evaporating fan 8, the second electronic expansion valve 6, the first electronic expansion valve 4 and the compressor 1 are started in turn. At this time, the required cooling capacity is very large, and the compressor 1 runs at a high speed. The refrigerant in the liquid-cooled evaporator 5 changes phase to cool the coolant, and the evaporating fan 8 provides cold air to the people in the cabin through the air duct 9.

[0050] In the cabin personnel heating mode, first, start the liquid cooling circulation loop, adjust the first three-way valve 21, the second three-way valve 23 and the third three-way valve 24, so that the valve ports of the first three-way valve 21 are all open, only the 2B port and the 2C port of the second three-way valve 23 are open, and only the 3A port and the 3C port of the third three-way valve 24 are open, open the switching valve 22, and then start the boost pump 10, the coolant absorbs heat through the power battery 14, and then part of the coolant flows back to the liquid storage tank through the third three-way valve 24, and the rest enters the first electromechanical control box 15 and the second The motor control box 16, the first motor 17 and the second motor 18 absorb heat, and by adjusting the opening of the first three-way valve 211C and 1B, the flow rate of this part of the coolant is controlled to increase its temperature, and then the coolant flows into the radiator 26 in the cabin through the switching valve 22 and the second three-way valve 23, and finally flows back to the storage tank 27 for recirculation; at this time, only the evaporating fan 8 of the evaporative cycle refrigeration circuit is started, and the cold air in the cabin sucked by it enters the radiator 26 in the cabin to absorb the heat of the high-temperature coolant, and then enters the cabin to heat the people in the cabin.

[0051] Embodiment 2: Ground work

[0052] When the electric drive vertical take-off and landing aircraft is on the ground, its heat dissipation mode is the same as the air mode. The main difference is in the heating mode. When on the ground, the motor control box and the motor are not working, and there is no heat source on the aircraft. In order to reduce the weight on the aircraft, the ground heating device is required for ground heating. The ground heating mode of the thermal management system includes a power battery heating mode and a power battery and cabin personnel heating mode.

[0053] Only the power battery heating mode is Figure 2 As shown, first, the ground heating device 28 is connected to the heating joint 11. Secondly, the liquid cooling circulation loop is started, and the first three-way valve 21, the second three-way valve 23 and the third three-way valve 24 are adjusted so that only the 1A port and the 1B port of the first three-way valve 21 are opened, the valve ports of the second three-way valve 23 are all closed, and only the 3A port and the 3C port of the third three-way valve 24 are opened, and then the booster pump 10 is started to drive the low-temperature coolant to flow into the ground heating device 28 for heating. The heated coolant enters the power battery 14 for heating, and then flows back to the liquid storage tank 27 through the first three-way valve 21 and the third three-way valve 24 for recirculation. At this time, the evaporative cycle refrigeration loop does not need to be started.

[0054] The power battery and cabin personnel are heated simultaneously. Figure 2 As shown, firstly, the ground heating device 28 is connected to the heating joint 11; secondly, the liquid cooling circulation loop is started, and the first three-way valve 21, the second three-way valve 23 and the third three-way valve 24 are adjusted so that only the 1A port and the 1B port of the first three-way valve 21 are opened, only the 2A port and the 2C port of the second three-way valve 23 are opened, and only the 3A port and the 3B port of the third three-way valve 24 are opened, and then the booster pump 10 is started to drive the low-temperature coolant to flow into the ground heating device 28 for heating. The heated coolant first enters the power battery 14 for heating, and then flows into the cabin radiator 26 through the first three-way valve 21, the third three-way valve 24 and the second three-way valve 23, and then flows back to the liquid storage tank 27 for recirculation. At this time, only the evaporation fan 8 of the evaporation cycle refrigeration loop is started, and the cold air sucked by it enters the cabin radiator 26 to absorb the heat of the high-temperature coolant, and then enters the cabin to heat the cabin personnel.

[0055] The article explains the principles and implementation methods of the patent of the present invention. It should be pointed out that several improvements and modifications can be made to it without departing from the principles of the present invention, but these improvements and modifications also fall within the scope of protection of the claims of the patent of the present invention.

Claims

1. An aircraft thermal management system, characterized in that: Including evaporative cycle refrigeration circuit, liquid cooling cycle circuit, power battery, motor control box and motor; The cabin evaporator of the evaporative cycle refrigeration circuit and the cabin radiator of the liquid cooling cycle circuit are arranged in the same air duct, and the liquid cooling cycle circuit flows through the power battery, the motor control box and the motor to dissipate heat for them; An evaporating fan is arranged in the air duct.

2. The system according to claim 1, characterized in that: The evaporative cycle refrigeration circuit includes: compressor, condenser, condensing fan and cabin evaporator; The left end of the cabin evaporator is connected to the compressor, the condenser, the first electronic expansion valve and the right end of the cabin evaporator in sequence through pipelines; The condensing fan dissipates heat for the condenser.

3. The system according to claim 2, characterized in that: The liquid cooling circulation loop includes: the right end of the cabin radiator, a liquid storage tank, a liquid cooling evaporator, a boost pump, a heating joint, a power battery, a motor control box, a motor, and the left end of the cabin radiator which are connected in sequence through pipelines.

4. The system according to claim 3, characterized in that: A first three-way valve is provided at the outlet of the liquid cooling circuit of the power battery, and a second three-way valve is provided at the left end of the radiator in the cabin; Port 1A of the first three-way valve is connected to the outlet of the power battery liquid cooling circuit, port 1B of the first three-way valve is connected to port 2A of the second three-way valve through a pipeline, and port 1C of the first three-way valve is connected to the inlet of the motor cooling unit; the outlet of the motor cooling unit is connected to port 2B of the second three-way valve, and port 2C of the second three-way valve is connected to the left end of the radiator in the cabin.

5. The system according to claim 4, characterized in that: The motor cooling unit includes two parallel branches, each branch including a motor control box and a motor.

6. The system according to claim 5, characterized in that: A switching valve is provided between the outlet of the motor cooling unit and the 2B port of the second three-way valve, and the switching valve is connected in parallel with the skin radiator.

7. The system according to claim 6, characterized in that: A third three-way valve is provided on the pipeline between port 1B of the first three-way valve and port 2A of the second three-way valve, port 3A of the third three-way valve is connected to port 1B of the first three-way valve, port 3B of the third three-way valve is connected to port 2A of the second three-way valve, and port 3C of the third three-way valve is connected to the right end of the radiator in the cabin.

8. The system according to claim 7, characterized in that: The liquid-cooled evaporator is connected between the liquid storage tank and the boost pump, the cabin radiator is connected between the skin radiator and the liquid storage tank, and a second electronic expansion valve is arranged between the liquid-cooled evaporator and the condenser.

9. A method for controlling an aircraft thermal management system, used to control any of the above-mentioned systems, characterized in that: include: Method 1: Close the second electronic expansion valve, and start the evaporator fan, condenser fan, first electronic expansion valve and compressor in sequence to cool the cabin; Method 2: The liquid cooling circulation loop is open, and the first three-way valve and the third three-way valve are adjusted so that the outlet of the power battery liquid cooling loop is directly connected to the liquid storage tank, so as to cool only the power battery; Method 3: The liquid cooling circulation loop is turned on, and the first, second, and third three-way valves are adjusted, and the switching valve is opened so that the outlet of the power battery liquid cooling loop is directly connected to the liquid storage tank, and at the same time, the outlet of the power battery liquid cooling loop is connected to the motor cooling unit and then directly connected to the liquid storage tank; Method 4: Switch the valve to close based on method 3.

10. The method according to claim 9, characterized in that: When in ground state, connect the ground heating device through the heating joint.

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