Thermal management system and control method for hybrid aircraft

Abstract

The invention provides a thermal management system and a control method for a hybrid aircraft, the thermal management system comprises a fuel oil loop and a fuel oil loop, the fuel oil loop comprises a fuselage skin heat exchanger and a cooling liquid-fuel oil heat exchanger, and the fuselage skin heat exchanger performs heat exchange on air and fuel oil; the cooling liquid-fuel oil heat exchanger is used for carrying out heat exchange on cooling liquid and fuel oil; the subsystem cooling liquid loop is used for inputting cooling liquid in the cooling liquid-fuel oil heat exchanger into the subsystem so as to cool the subsystem; and the battery temperature control system controls the working mode of the subsystem cooling liquid loop according to the temperature of the battery. According to the heat management system architecture, airborne fuel oil and ram air serve as cold sources, and high-temperature cooling liquid flowing through a cooling loop serves as a heat source, so that the cooling function of all parts of the hybrid power system and the temperature control function of a battery are achieved, the burden of the fuel oil serving as a heat sink is reduced, and the situation that the temperature of the fuel oil is too high and exceeds the permissible temperature of an engine is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of thermal management system design of hybrid aircraft, in particular to a thermal management system and control method for hybrid aircraft. BACKGROUND

[0002] From the current development of the aviation industry, energy saving and low carbon is the trend of the aviation industry. Various aviation enterprises are actively developing different configurations of hybrid electric propulsion test and verification. By introducing the power system, the traditional engine can always work in a better state, and the oil saving goal can be achieved by improving the engine performance matching.

[0003] With the demand of hybrid aircraft for larger power level of power system and the improvement of integration level of power system components, the heat dissipation demand of hybrid aircraft also rises rapidly. Compared with the traditional wing-mounted propulsion system, a large number of power equipment are limited by installation space and structural bearing capacity, and can only be integrated and installed in the cabin, and cannot be exposed outside like the wing-mounted power, and cannot directly exchange heat with the high-speed airflow outside the nacelle.

[0004] The generator, motor and power converter in the hybrid power system dissipate heat in the form of electric energy loss when working, which needs to be removed by the thermal management system in time, otherwise the heat will continue to accumulate, which will cause the temperature rise in the subsystem and the cabin, resulting in demagnetization of permanent magnet and burning.

[0005] At present, the heat dissipation technology of hybrid system is divided into air cooling and liquid cooling. If air cooling is adopted, all power systems need to be placed outside the cabin, or a cooling gas inlet is added at the fuselage, which will greatly affect the flight performance of the aircraft. However, the fin structure of the air-cooled liquid heat exchanger has a large design margin, which can be more easily integrated with the fuselage skin. Therefore, the cooling liquid can be used as a medium to transport the heat of the power system in the cabin to the heat exchanger integrated with the fuselage, and exchange heat with the outside atmosphere, which can improve the integration degree of the thermal management system and reduce the burden of the fuel heat sink, and avoid the influence of excessive fuel temperature rise on the operation of the aircraft engine.

[0006] Hybrid power systems have various configurations, for example, series hybrid is to convert all the energy of the prime mover into electric energy, and then use electric energy for propulsion. Parallel hybrid is to provide power by the prime mover and the power system at the same time. The difference between different hybrid configurations is mainly the proportion of electric propulsion power, that is, the power mixing degree is different. However, the main components are basically the same, including prime mover, generator, power converter, battery and controller. The difference is mainly in the power level of different components, but all these systems need to be cooled.

[0007] At present, the existing thermal management system scheme design is mainly concentrated on the further optimization of the thermal management system of traditional fuel-powered aircraft and the architecture design of the thermal management system of hybrid electric vehicles. For hybrid electric aircraft which is still in a new field, there is no related design patent of the thermal management system of hybrid electric aircraft which is optimized according to its characteristics.

[0008] However, the thermal management system of hybrid electric aircraft has different heat dissipation requirements from the thermal management systems of ordinary aircraft and vehicles, such as larger power motors, electric control system cooling, large-capacity battery system temperature control, and using fuel and external atmosphere as a cold source which cannot be used by vehicles.

[0009] Therefore, the present application inventors design a thermal management system and control method for hybrid electric aircraft to overcome the above technical problems. SUMMARY

[0010] The technical problem solved by the present application is to overcome the defects in the prior art that the thermal management system is not designed for hybrid electric aircraft and cannot be used for hybrid electric aircraft with different hybrid configurations, and to provide a thermal management system and control method for hybrid electric aircraft.

[0011] The present application solves the above technical problems by the following technical solutions:

[0012] A thermal management system for hybrid electric aircraft, characterized in that the thermal management system comprises:

[0013] a fuel circuit, the fuel circuit comprising a fuselage skin heat exchanger and a coolant-oil heat exchanger, the fuselage skin heat exchanger performing heat exchange between air and fuel, and the coolant-oil heat exchanger performing heat exchange between coolant and fuel;

[0014] a subsystem coolant circuit, the subsystem coolant circuit inputting the coolant in the coolant-oil heat exchanger into a subsystem to cool the subsystem;

[0015] a battery temperature control system, the battery temperature control system controlling the working mode of the subsystem coolant circuit according to the temperature of the battery.

[0016] According to one embodiment of the present application, the fuel circuit further comprises a fuel pump and a fuel tank, and the fuselage skin heat exchanger, the fuel tank, the fuel pump and the coolant-oil heat exchanger are connected in sequence along the fuel flow direction on the fuel circuit to form a ring circuit.

[0017] According to one embodiment of the present application, the subsystem coolant circuit comprises:

[0018] A prime mover cooling liquid circuit for inputting the cooling liquid in the cooling liquid-fuel heat exchanger into a prime mover system to cool the prime mover system;

[0019] A generator cooling liquid circuit for inputting the cooling liquid in the cooling liquid-fuel heat exchanger into a generator system to cool the generator system;

[0020] A battery cooling liquid circuit for inputting the cooling liquid in the cooling liquid-fuel heat exchanger into a battery system to cool the battery system;

[0021] The prime mover cooling liquid circuit, the generator cooling liquid circuit and the battery cooling liquid circuit are arranged in parallel with each other.

[0022] According to one embodiment of the present application, on the prime mover cooling liquid circuit, the cooling liquid-fuel heat exchanger, a first cooling liquid pump and a prime mover are arranged in sequence along the cooling liquid flow direction.

[0023] According to one embodiment of the present application, on the generator cooling liquid circuit, the cooling liquid-fuel heat exchanger, a second cooling liquid pump, a generator controller, a generator, a motor controller and a motor are arranged in sequence along the cooling liquid flow direction.

[0024] According to one embodiment of the present application, on the battery cooling liquid circuit, the cooling liquid-fuel heat exchanger, a third cooling liquid pump and a battery are arranged in sequence along the cooling liquid flow direction.

[0025] According to one embodiment of the present application, the cooling liquid outlet of the prime mover on the prime mover cooling liquid circuit is communicated with the battery cooling liquid circuit through a first pipeline, and the cooling liquid outlet of the motor on the generator cooling liquid circuit is communicated with the battery cooling liquid circuit through a second pipeline.

[0026] According to one embodiment of the present application, a first electromagnetic valve is arranged on the first pipeline, a second electromagnetic valve is arranged on the second pipeline, and a third electromagnetic valve is arranged on the battery cooling liquid circuit.

[0027] The present application also provides a control method of a thermal management system for a hybrid aircraft, characterized in that the control method adopts the thermal management system for a hybrid aircraft as described above, and independently judges the battery temperature according to different flight conditions, and selects the corresponding working mode of the battery temperature control system;

[0028] Suppose that the temperature suitable range of the battery is Tmin to Tmax, a suitable safety temperature threshold Tsafe is selected, then:

[0029] Mode one: if the battery temperature is between Tmin+Tsafe and Tmax-Tsafe, the battery is in the most suitable temperature interval, no temperature control is needed, and the passive temperature control mode is adopted; at this time, the electromagnetic valves of the battery cooling pipeline and the heating pipeline are closed simultaneously;

[0030] Mode two: if the battery temperature is higher than Tmax-Tsafe, the battery temperature is higher than the suitable temperature interval, the battery needs to be cooled, and the active cooling mode is adopted;

[0031] At this time, by controlling the pipeline electromagnetic valve, the high-temperature cooling liquid pipeline after flowing through the component cooling pipeline is closed, only the low-temperature cooling liquid input pipeline is connected, the cooling of the battery is completed, and the battery heat is transferred to the fuel oil through the cooling liquid-fuel oil heat exchanger;

[0032] Mode three: if the battery temperature is lower than Tmin+Tsafe, the battery temperature is lower than the suitable temperature interval, the battery needs to be heated, and the active heating mode is adopted;

[0033] At this time, by controlling the opening and closing degree of the pipeline electromagnetic valve, the proportion of the high-temperature cooling liquid pipeline after flowing through the component cooling loop and the low-temperature cooling liquid input pipeline without cooling is controlled, and the cooling liquid with a suitable temperature is obtained to control the heating power of the battery.

[0034] According to one embodiment of the present application, when the mode three is in the active heating mode, the method further comprises: judging the power level of the power system;

[0035] If the power system is in a low working condition, the low-temperature cooling liquid input is opened, the engine cooling loop input is opened, and the power component cooling loop input is closed;

[0036] If the power system is in a high working condition, the low-temperature cooling liquid input is opened, the engine cooling loop input is opened, and the power component cooling loop input is opened.

[0037] According to one embodiment of the present application, when the mode three is in the active heating mode, the control process of the power system power in the low working condition comprises:

[0038] The target temperature is selected as: T_set=(Tmin+Tmax) / 2;

[0039] The battery temperature deviation is calculated: T_Error=T_Battery-T_set;

[0040] The high and low temperature fuel mixing ratio is adjusted according to the temperature deviation:

[0041] The engine cooling loop flow ratio is calculated: K_Hot_Engine=(T_set-T_cold) / (T_Engine-T_cold);

[0042] Calculate the flow rate proportion of the electric power system cooling loop: K_Hot_Elec = 0;

[0043] Calculate the flow rate proportion of the low-temperature cooling liquid loop: K_Cold = 1 - K_Hot_Engine;

[0044] Wherein: T_cold is the temperature of the cooling liquid in the low-temperature cooling loop, T_Engine is the temperature of the cooling liquid in the engine cooling loop, and T_Elec is the temperature of the cooling liquid in the electric power system cooling loop.

[0045] According to the T_Battery table, the total flow rate Q_total required by the battery system is obtained;

[0046] Calculate the flow rate provided by the engine cooling loop: Q_Hot_Engine = Q_total * K_Hot_Engine;

[0047] Calculate the flow rate provided by the electric power system cooling loop: Q_Hot_Elec = 0;

[0048] Calculate the flow rate provided by the low-temperature cooling liquid loop: Q_Cold = 1 - Q_total * K_Cold;

[0049] According to the expected flow rate, carry out flow rate feedback control.

[0050] According to one embodiment of the present application, when the mode three is in the active heating mode, the control process of the electric power system power under the high working condition includes:

[0051] The target temperature is selected as: T_set = (Tmin + Tmax) / 2;

[0052] Calculate the battery temperature deviation: T_Error = T_Battery - T_set;

[0053] Adjust the mixing proportion of high and low temperature fuels according to the temperature deviation;

[0054] Obtain the relationship of T_set, T_Engine, T_Elec, T_cold and the two-way high-temperature loop flow rate weight coefficients K1 and K2 through optimization, wherein K1 + K2 = 1;

[0055] Calculate the flow rate proportion of the engine cooling loop: K_Hot_Engine = (T_set - T_cold) / (T_Engine - T_cold) * K1;

[0056] Calculate the flow rate proportion of the electric power system cooling loop: K_Hot_Elec = (T_set - T_cold) / (T_Elec - T_cold) * K2;

[0057] Calculate the low-temperature cooling liquid circuit flow ratio: K_Cold = 1 - K_Hot_Engine - K_Hot_Elec;

[0058] Wherein: T_cold is the temperature of the cooling liquid in the low-temperature cooling circuit, T_Engine is the temperature of the cooling liquid in the engine cooling circuit, and T_Elec is the temperature of the cooling liquid in the electric power system cooling circuit.

[0059] Obtain the total flow Q_total required for the battery system temperature control according to the T_Battery lookup table;

[0060] Calculate the engine cooling circuit flow: Q_Hot_Engine = Q_total * K_Hot_Engine;

[0061] Calculate the electric power system cooling circuit flow: Q_Hot_Elec = Q_total * K_Hot_Elec;

[0062] Calculate the low-temperature cooling liquid circuit flow: Q_Cold = 1 - Q_total * K_Cold;

[0063] Carry out flow feedback control according to the expected flow.

[0064] The positive progress effect of the present application is that:

[0065] The present application is a thermal management system and control method for a hybrid aircraft, which adopts airborne fuel and ram air as a cold source and high-temperature cooling liquid flowing through a cooling circuit as a heat source, realizes the cooling of each component of the hybrid power system and the temperature control of the battery, reduces the burden of fuel as a heat sink, and avoids the fuel temperature from being too high to exceed the engine allowable temperature.

[0066] The proportion between the high-temperature cooling liquid flowing through the cooling circuit and the low-temperature cooling liquid without cooling is adjusted by the opening of the pipeline electromagnetic valve to obtain temperature control liquid with a suitable temperature, realize the utilization of waste heat of the hybrid power system, and realize the battery warming function with low energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0067] The above and other features, properties, and advantages of the present application will become more apparent through the following description with reference to the accompanying drawings and embodiments, in which the same reference numerals represent the same features throughout the drawings, in which:

[0068] Figure 1 The structure diagram of the thermal management system for a hybrid aircraft of the present application.

[0069] Figure 2For the heat management system for hybrid aircraft of the present application, battery passive cooling mode operation logic diagram.

[0070] Figure 3 For the heat management system for hybrid aircraft of the present application, battery cooling mode operation logic diagram.

[0071] Figure 4 For the heat management system for hybrid aircraft of the present application, battery heating mode operation logic diagram when the hybrid system is working in low operating condition.

[0072] Figure 5 For the heat management system for hybrid aircraft of the present application, battery heating mode operation logic diagram when the hybrid system is working in high operating condition.

[0073] Figure 6 Flow chart of the control method for the heat management system for hybrid aircraft of the present application. DETAILED DESCRIPTION

[0074] In order to make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0075] Reference will now be made in detail to the embodiments of the present application, examples of which are illustrated in the accompanying drawings. The detailed description of the present application will be made with specific reference to the preferred embodiments of the present application, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0076] In addition, although the terms used in the present application are selected from publicly-known terms, some of the terms mentioned in the specification of the present application can be selected by the applicant in his or her judgment, and the detailed meanings thereof are described in the relevant part of the description herein.

[0077] In addition, the present application should be understood not only by the actual terms used, but also by the meanings implied by each term.

[0078] As Figures 1 to 5 As shown in the drawings, the present application discloses a heat management system for hybrid aircraft, which focuses on the architecture design of the heat management system that meets the additional technical requirements of hybrid aircraft, and selects the outside atmosphere and the on-board fuel as the cold source and the high-temperature cooling liquid after cooling as the heat source in combination with the characteristics of the aircraft.

[0079] The thermal management system comprises a fuel circuit 100, a subsystem coolant circuit 200 and a battery temperature control system 300. The fuel circuit 100 comprises an airframe skin heat exchanger 110 for exchanging heat between air and fuel, and a coolant-fuel heat exchanger 120 for exchanging heat between coolant and fuel. The subsystem coolant circuit 200 inputs the coolant in the coolant-fuel heat exchanger 120 into subsystems to cool the subsystems. The battery temperature control system 300 controls the working mode of the subsystem coolant circuit 200 according to the temperature of the battery.

[0080] Preferably, the fuel circuit 100 further comprises a fuel pump 130 and a fuel tank 140, and the airframe skin heat exchanger 110, the fuel tank 140, the fuel pump 130 and the coolant-fuel heat exchanger 120 are connected in sequence along the fuel flow direction on the fuel circuit 100 to form a loop circuit.

[0081] Preferably, the subsystem coolant circuit 200 comprises a prime mover coolant circuit 210 for inputting the coolant in the coolant-fuel heat exchanger 120 into a prime mover system to cool the prime mover system, a generator coolant circuit 220 for inputting the coolant in the coolant-fuel heat exchanger 120 into a generator system to cool the generator system, and a battery coolant circuit 230 for inputting the coolant in the coolant-fuel heat exchanger 120 into a battery system to cool the battery system. The prime mover coolant circuit 210, the generator coolant circuit 220 and the battery coolant circuit 230 are parallelly connected to each other.

[0082] On the prime mover coolant circuit 210, the coolant-fuel heat exchanger 120, a first coolant pump 211 and a prime mover 212 are sequentially arranged along the coolant flow direction.

[0083] On the generator coolant circuit 220, the coolant-fuel heat exchanger 120, a second coolant pump 221, a generator controller 222, a generator 223, an electric motor controller 224 and an electric motor 225 are sequentially arranged along the coolant flow direction.

[0084] On the battery coolant circuit 230, the coolant-fuel heat exchanger 120, a third coolant pump 231 and a battery 232 are sequentially arranged along the coolant flow direction.

[0085] The coolant outlet of the prime mover on the prime mover coolant circuit 210 is communicated with the battery coolant circuit 230 through a first pipeline 213, and the coolant outlet of the electric motor 225 on the generator coolant circuit 220 is communicated with the battery coolant circuit 230 through a second pipeline 226.

[0086] In addition, a first electromagnetic valve 214 is arranged on the first pipeline 213, a second electromagnetic valve 227 is arranged on the second pipeline 226, and a third electromagnetic valve is arranged on the battery cooling liquid circuit 230.

[0087] According to the above description, the heat management system for the hybrid aircraft adopts a two-stage cooling architecture, absorbs heat generated by different components during operation by using cooling liquid, and flows into a cooling liquid-fuel heat exchanger after collection, and absorbs heat in the cooling liquid of each subsystem by using fuel as a medium.

[0088] After the heat exchange between the cooling liquid and the fuel is completed, the low-temperature cooling liquid is recycled for component cooling, and the high-temperature fuel is introduced into an air-fuel heat dissipation structure integrated with the aircraft skin, so as to transfer heat to the atmosphere outside the aircraft skin, realize cooling of the fuel, and take away the heat generated during operation of the hybrid aircraft.

[0089] By adjusting the opening of the pipeline electromagnetic valve, the proportion of the high-temperature cooling liquid flowing through the cooling circuit and the low-temperature cooling liquid without cooling is obtained, and the temperature control liquid with a suitable temperature is obtained, the utilization of waste heat of the hybrid power system is realized, and the temperature control of the battery cooling and heating is realized with low energy consumption.

[0090] In the present application, various forms can be used between the subsystem cooling liquid circuits, for example:

[0091] I. In series, using the same cooling liquid and the same cooling circuit to cool each subsystem in turn;

[0092] II. In parallel, different cooling liquids and independent cooling circuits can be used according to the special needs of each subsystem;

[0093] III. A combination of the two ways, in the subsequent embodiment diagram (for example Figures 2 to 5 ) a series architecture is described.

[0094] Figures 2 to 5 The running logic diagram of the heat management system when the battery is in different temperature control modes is shown, wherein the solid arrows represent the flow direction of the cooling liquid, and the dashed lines represent that the cooling liquid does not flow in the pipeline. In the figure, M1-M4 represent different pumps for maintaining the flow in the pipeline.

[0095] As Figure 6 shown, the present application also provides a control method for a heat management system for a hybrid aircraft, which adopts the heat management system for a hybrid aircraft as described above, independently judges the battery temperature according to different flight conditions, and selects the corresponding working mode of the battery temperature control system;

[0096] Assuming that the temperature range of the battery is Tmin to Tmax, a suitable safety temperature threshold Tsafe is selected, and then:

[0097] Mode one: if the battery temperature is between Tmin+Tsafe and Tmax-Tsafe, the battery is in the most suitable temperature range, and no temperature control is needed. At this time, the battery cooling pipeline and heating pipeline electromagnetic valves are closed at the same time, and the passive temperature control mode is adopted (as shown in Figure 2

[0098] Mode two: if the battery temperature is higher than Tmax-Tsafe, the battery temperature is higher than the suitable temperature range, and the battery needs to be cooled, and the active cooling mode is adopted.

[0099] At this time, by controlling the pipeline electromagnetic valve, the high-temperature cooling liquid pipeline after the component cooling pipeline is closed, only the low-temperature cooling liquid input pipeline is connected, and after the cooling of the battery is completed, the cooling liquid-fuel heat exchanger is flowed into, and the battery heat is transferred to the fuel (as shown in Figure 3

[0100] Mode three: if the battery temperature is lower than Tmin+Tsafe, the battery temperature is lower than the suitable temperature range, and the battery needs to be heated, and the active heating mode is adopted.

[0101] At this time, by controlling the opening and closing degree of the pipeline electromagnetic valve, the proportion of the high-temperature cooling liquid pipeline after the component cooling loop and the low-temperature cooling liquid input pipeline without cooling is controlled, and the cooling liquid with a suitable temperature is obtained to control the heating power of the battery.

[0102] Preferably, when the mode three is in the active heating mode, it further includes: judging the power level of the power system.

[0103] If the power system is in low working condition, the low-temperature cooling liquid input is opened, the engine cooling loop input is opened, and the power component cooling loop input is closed. That is, when the power level of the power system is low, only the cooling liquid flowing through the engine cooling loop is used as a heat source to heat the battery (as shown in Figure 4

[0104] If the power system is in high working condition, the low-temperature cooling liquid input is opened, the engine cooling loop input is opened, and the power component cooling loop input is opened. That is, when the power level of the power system is high, the cooling liquid flowing through the power system cooling loop and the engine cooling loop is mixed and used as a heat source to heat the battery (as shown in Figure 5

[0105] When the mode three is in the active heating mode, the control logic of the power system power in the low working condition includes:

[0106] ​​​​The target temperature is selected as T_set=(Tmin+Tmax) / 2, which can be optimized and adjusted according to the actual situation of weather and power system load;

[0107] The battery temperature deviation is calculated as T_Error=T_Battery-T_set;

[0108] The high and low temperature fuel mixture ratio is adjusted according to the temperature deviation:

[0109] The engine cooling loop flow ratio is calculated as K_Hot_Engine=(T_set-T_cold) / (T_Engine-T_cold);

[0110] The power system cooling loop flow ratio is calculated as K_Hot_Elec=0;

[0111] The low temperature cooling liquid loop flow ratio is calculated as K_Cold=1-K_Hot_Engine;

[0112] Wherein: T_cold is the temperature of the cooling liquid in the low temperature cooling loop, T_Engine is the temperature of the cooling liquid in the engine cooling loop, and T_Elec is the temperature of the cooling liquid in the power system cooling loop;

[0113] According to T_Battery, the total flow Q_total required by the battery system is obtained;

[0114] The engine cooling loop flow is calculated as Q_Hot_Engine=Q_total*K_Hot_Engine;

[0115] The power system cooling loop flow is calculated as Q_Hot_Elec=0;

[0116] The low temperature cooling liquid loop flow is calculated as Q_Cold=1-Q_total*K_Cold;

[0117] According to the expected flow, the flow feedback control is carried out.

[0118] Preferably, when the mode three is in the active heating mode, the power system power control process under high working condition includes:

[0119] The target temperature is selected as T_set=(Tmin+Tmax) / 2, which can be optimized and adjusted according to the actual situation of weather and power system load;

[0120] The battery temperature deviation is calculated as T_Error=T_Battery-T_set;

[0121] The high and low temperature fuel mixture ratio is adjusted according to the temperature deviation:

[0122] The relationship of T_set, T_Engine, T_Elec, T_cold and two high-temperature loop flow weight coefficients K1, K2 is optimized, wherein K1+K2=1;

[0123] The engine cooling loop flow ratio is calculated: K_Hot_Engine=(T_set-T_cold) / (T_Engine-T_cold)*K1;

[0124] The power system cooling loop flow ratio is calculated: K_Hot_Elec=(T_set-T_cold) / (T_Elec-T_cold)*K2;

[0125] The low-temperature cooling liquid loop flow ratio is calculated: K_Cold=1-K_Hot_Engine-K_Hot_Elec;

[0126] Wherein: T_cold is the temperature of the cooling liquid in the low-temperature cooling loop, T_Engine is the temperature of the cooling liquid in the engine cooling loop, and T_Elec is the temperature of the cooling liquid in the power system cooling loop.

[0127] The total flow Q_total required by the battery system is obtained according to the T_Battery table;

[0128] The engine cooling loop flow Q_Hot_Engine is calculated: Q_Hot_Engine=Q_total*K_Hot_Engine;

[0129] The power system cooling loop flow Q_Hot_Elec is calculated: Q_Hot_Elec=Q_total*K_Hot_Elec;

[0130] The low-temperature cooling liquid loop flow Q_Cold is calculated: Q_Cold=1-Q_total*K_Cold;

[0131] The flow feedback control is carried out according to the expected flow.

[0132] According to the description of the above control method, the operation mode of the thermal management system for different aircraft flight conditions is:

[0133] I. In the ground slow vehicle state, the power system heat generation is low, and the heat source mainly comes from the engine cooling liquid loop. There is no air ram effect, and the cold source is only the on-board fuel, but because the working time is short, it can rely on the fuel-cooling liquid heat exchanger loop to carry out heat dissipation.

[0134] At this time, the component cooling circuit runs at the lowest flow rate, and after the component cooling is completed, the heat exchange between the coolant and the fuel is carried out, the fuel absorbing the heat of the coolant only passes through the air-fuel radiator, but does not carry out a large degree of heat exchange, and after flowing out of the heat exchanger, is directly combusted or flows back to the fuel tank.

[0135] II. In the ground take-off state, the engine and the power system work in a high-power state, and the heat source comes from the engine and the power system cooling circuit. At the same time, because the flight speed of the aircraft is low, the ram effect of the airflow is weak, and the cold source is still mainly the on-board fuel. However, because the working time is also short, the heat dissipation can be carried out entirely by relying on the fuel-coolant heat exchanger circuit, which is the maximum load state of the thermal management system.

[0136] At this time, the component cooling circuit runs at the highest flow rate, and after the component cooling is completed, the heat exchange between the coolant and the fuel is carried out, the fuel absorbing the heat of the coolant only passes through the air-fuel radiator, but does not carry out a large degree of heat exchange, and after flowing out of the heat exchanger, is directly combusted or flows back to the fuel tank.

[0137] III. In the climbing state, the engine and the power system still work in a high-power state, and the heat source comes from the engine and the power system cooling circuit. However, with the increase of the flight speed and the height, the ram airflow appears on the surface of the fuselage, and the temperature of the airflow decreases. Therefore, the air-coolant heat exchanger circuit can work simultaneously with the fuel-coolant heat exchanger circuit, and the cold source is jointly borne by the external ram air and the fuel.

[0138] At this time, the component cooling circuit runs at a high flow rate, and after the component cooling is completed, the heat exchange between the coolant and the fuel is carried out, the fuel absorbing the heat of the coolant passes through the air-fuel radiator, and the heat of the fuel is transmitted to the ram airflow flowing through the surface of the fuselage, and after flowing out of the heat exchanger, is directly combusted or flows back to the fuel tank.

[0139] IV. In the cruising state, the engine and the power system work in a low-power state, and the heat source comes from the engine and the power system cooling circuit. The flight speed and the height in the cruising state are high, and the low-temperature ram airflow on the surface of the fuselage has the highest heat dissipation capacity, which can bear the main heat dissipation load at this time.

[0140] At this time, the component cooling circuit runs at a low flow rate, and after the component cooling is completed, the heat exchange between the coolant and the fuel is carried out, the fuel absorbing the heat of the coolant passes through the air-fuel radiator, and the heat of the fuel is transmitted to the ram airflow flowing through the surface of the fuselage, and after flowing out of the heat exchanger, is directly combusted or flows back to the fuel tank.

[0141] As described above, the thermal management system for a hybrid aircraft and the control method thereof have the following characteristics:

[0142] I. Compared with the traditional aircraft thermal management system, the hybrid aircraft introduces new subsystems such as motors, batteries, electric controls, etc. The present application proposes a new thermal management system architecture and control logic that is more suitable for hybrid aircraft to meet the heat dissipation requirements of these new components, and provides a general thermal management system framework for hybrid aircraft with different hybrid configurations.

[0143] II. The present application provides thermal management system control switching logic for different flight conditions and operating modes of the aircraft.

[0144] III. The present application makes full use of the waste heat generated by the hybrid power system during operation as a heat source to achieve battery warming function at high altitude or low temperature, reducing the system heat dissipation requirement and saving the energy required for battery warming.

[0145] IV. Based on the traditional fuel cold source, the present application integrates the heat exchanger with the aircraft fuselage, fully utilizes the ram air generated during flight as an additional cold source, meets the additional power system heat dissipation power requirement at a small cost, and reduces the heat dissipation burden of fuel as a cold source.

[0146] In summary, the present application provides a thermal management system and control method for hybrid aircraft, which adopts an on-board fuel and ram air as a cold source, and a high-temperature cooling liquid after flowing through the cooling circuit as a heat source. The thermal management system architecture not only realizes the cooling of each component of the hybrid power system and the temperature control function of the battery, but also reduces the burden of fuel as a heat sink, avoiding the fuel temperature from being too high to exceed the engine allowable temperature.

[0147] By adjusting the opening of the pipeline solenoid valve, the proportion of high-temperature cooling liquid after flowing through the cooling circuit and low-temperature cooling liquid without cooling is obtained to obtain a suitable temperature of the temperature control liquid, realizing the utilization of waste heat of the hybrid power system, and achieving the battery warming function with low energy consumption.

[0148] For those skilled in the art, the above disclosure of the application is only as an example and does not constitute a limitation on the present application. Although it is not explicitly stated here, those skilled in the art can make various modifications, improvements and corrections to the present application. Such modifications, improvements and corrections are suggested in the present application, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the present application.

[0149] Also, the use of "a" or "an" to describe an item or feature of the application should be taken to mean "one or more" unless otherwise indicated. Furthermore, the use of the term "including" as well as other forms for, e.g., "include", "includes", "included", "including", "contain", "contains", "contained", etc., should be taken to be open-ended, meaning that there are other items or features that are also contained within the present application. As used herein, the term "exemplary" is used interchangeably with "for illustration," "for example," and "by way of example." The terms "example" and "exemplary" are used to indicate functionality, the possession of which by a component, instrumentality, or article of manufacture, makes it suitable for

[0150] Similarly, it is to be noticed that the term "comprising", used in the description, should not be interpreted as being restricted only to the means of the recitation of the patent claim. It is thus to be understood that other items can be said to be "comprised" by any of the patent claims of the present application, to the extent that the claims do not, in their context, exclude other items.

[0151] While the application has been described in connection with specific embodiments thereof, it will be understood that it is carried out in subtilty and the scope of the application is indicated by the appended claims. Changes in form and details of the application can be made without departing from the spirit and scope of the application.

Claims

1. A thermal management system for a hybrid-electric aircraft, characterized in that, The thermal management system includes: The fuel circuit includes a fuselage skin heat exchanger and a coolant-fuel heat exchanger. The fuselage skin heat exchanger exchanges heat between air and fuel, and the coolant-fuel heat exchanger exchanges heat between coolant and fuel. Subsystem coolant circuit, wherein the subsystem coolant circuit inputs coolant from the coolant-fuel heat exchanger into the subsystem to cool the subsystem; A battery temperature control system, wherein the battery temperature control system controls the working mode of the coolant circuit of the battery temperature control subsystem.

2. The thermal management system for a hybrid-electric aircraft as described in claim 1, characterized in that, The fuel circuit also includes a fuel pump and a fuel tank. The fuselage skin heat exchanger, the fuel tank, the fuel pump, and the coolant-fuel heat exchanger are connected sequentially to the fuel circuit along the fuel flow direction to form a ring circuit.

3. The thermal management system for a hybrid-electric aircraft as described in claim 2, characterized in that, The subsystem coolant circuit includes: The prime mover coolant circuit is used to input the coolant in the coolant-fuel heat exchanger into the prime mover system to cool the prime mover system; A generator coolant circuit is used to introduce coolant from the coolant-fuel heat exchanger into the generator system to cool the generator system. A battery coolant circuit is used to introduce coolant from the coolant-fuel heat exchanger into the battery system to cool the battery system; The prime mover coolant circuit, the generator coolant circuit, and the battery coolant circuit are connected in parallel.

4. The thermal management system for a hybrid-electric aircraft as described in claim 3, characterized in that, The coolant circuit of the prime mover consists of, in sequence along the coolant flow direction, the coolant-fuel heat exchanger, the first coolant pump, and the prime mover.

5. The thermal management system for a hybrid-electric aircraft as described in claim 4, characterized in that, The generator coolant circuit consists of, in sequence along the coolant flow direction, the coolant-fuel heat exchanger, the second coolant pump, the generator controller, the generator, the motor controller, and the motor.

6. The thermal management system for a hybrid-electric aircraft as described in claim 5, characterized in that, The battery coolant circuit consists of, in sequence along the coolant flow direction, the coolant-fuel heat exchanger, the third coolant pump, and the battery.

7. The thermal management system for a hybrid-electric aircraft as described in claim 6, characterized in that, The coolant outlet of the prime mover in the prime mover coolant circuit is connected to the battery coolant circuit through a first pipe, and the coolant outlet of the motor in the generator coolant circuit is connected to the battery coolant circuit through a second pipe.

8. The thermal management system for a hybrid-electric aircraft as described in claim 7, characterized in that, A first solenoid valve is installed on the first pipeline, a second solenoid valve is installed on the second pipeline, and a third solenoid valve is installed on the battery coolant circuit.

9. A control method for a thermal management system of a hybrid-electric aircraft, characterized in that, The control method employs the thermal management system for hybrid-electric aircraft as described in any one of claims 1-8, which independently judges the battery temperature according to different flight conditions and selects the corresponding working mode of the battery temperature control system. Assuming the suitable temperature range for the battery is from Tmin to Tmax, and selecting a suitable safe temperature threshold Tsafe, then: Mode 1: If the battery temperature is between Tmin+Tsafe and Tmax-Tsafe, the battery is in the most suitable temperature range and no temperature control is required; it is in passive temperature control mode. At this time, the solenoid valves of the battery cooling pipe and heating pipe are closed simultaneously. Mode 2: If the battery temperature is higher than Tmax-Tsafe, the battery temperature is above the suitable temperature range and the battery needs to be cooled, so it is in active cooling mode. At this point, by controlling the solenoid valve of the pipeline, the high-temperature coolant pipeline after the component cooling pipeline is closed, and only the low-temperature coolant input pipeline is connected. After the battery is cooled, it flows into the coolant-fuel heat exchanger to transfer the battery heat to the fuel. Mode 3: If the battery temperature is lower than Tmin+Tsafe, the battery temperature is below the suitable temperature range and the battery needs to be heated, thus entering active heating mode; At this point, by controlling the opening and closing degree of the solenoid valves in the pipeline, the ratio of the high-temperature coolant pipeline after flowing through the component cooling circuit to the uncooled low-temperature coolant input pipeline is controlled, thereby obtaining coolant at a suitable temperature to control the heating power of the battery.

10. The control method for a thermal management system of a hybrid-electric aircraft as described in claim 9, characterized in that, When Mode 3 is in active heating mode, it also includes: determining the power system power level; If the power system is under low operating conditions, the low temperature coolant input is turned on, the engine cooling circuit input is turned on, and the power component cooling circuit input is turned off. If the electrical system is under high operating conditions, the cryogenic coolant input is turned on, the engine cooling circuit input is turned on, and the electrical component cooling circuit input is turned on.

11. The control method for a thermal management system of a hybrid-electric aircraft as described in claim 10, characterized in that, When Mode 3 is in active heating mode, the control process under low power conditions of the power system includes: The target temperature is selected as: T_set = (Tmin + Tmax) / 2; Calculate battery temperature deviation: T_Error = T_Battery – T_set; Adjust the mixing ratio of high and low temperature fuels according to the temperature deviation: Calculate the engine cooling circuit flow rate ratio: K_Hot_Engine = (T_set - T_cold) / (T_Engine - T_cold); Calculate the flow rate ratio of the power system cooling loop: K_Hot_Elec = 0; Calculate the flow rate ratio of the cryogenic coolant circuit: K_Cold = 1 - K_Hot_Engine; Where: T_cold is the coolant temperature in the low-temperature cooling circuit, T_Engine is the coolant temperature in the engine cooling circuit, and T_Elec is the coolant temperature in the power system cooling circuit; Based on T_Battery, look up the table to obtain the total temperature control flow rate Q_total required by the battery system; Calculate the flow rate provided by the engine cooling circuit: Q_Hot_Engine = Q_total * K_Hot_Engine; Calculate the flow rate supplied by the power system cooling loop: Q_Hot_Elec = 0; Calculate the flow rate supplied by the cryogenic coolant circuit: Q_Cold = 1 - Q_total * K_Cold; Traffic feedback control is implemented based on expected traffic volume.

12. The control method for a thermal management system of a hybrid-electric aircraft as described in claim 10, characterized in that, When Mode 3 is in active heating mode, the control process under high power conditions of the power system includes: The target temperature is selected as: T_set = (Tmin + Tmax) / 2; Calculate battery temperature deviation: T_Error = T_Battery – T_set; Adjust the mixing ratio of high and low temperature fuels according to the temperature deviation; The relationship between T_set, T_Engine, T_Elec, T_cold and the flow weight coefficients K1 and K2 of the two high-temperature loops is obtained by optimization, where K1+K2=1; Calculate the engine cooling circuit flow ratio: K_Hot_Engine = (T_set - T_cold) / (T_Engine - T_cold) * K1; Calculate the flow rate ratio of the power system cooling loop: K_Hot_Elec = (T_set - T_cold) / (T_Elec - T_cold) * K2; Calculate the flow rate ratio of the cryogenic coolant loop: K_Cold = 1 - K_Hot_Engine - K_Hot_Elec; Where: T_cold is the coolant temperature in the low-temperature cooling circuit, T_Engine is the coolant temperature in the engine cooling circuit, and T_Elec is the coolant temperature in the power system cooling circuit; The total required temperature control flow rate Q_total of the battery system is obtained by looking up the table based on T_Battery; Calculate the flow rate provided by the engine cooling circuit: Q_Hot_Engine = Q_total * K_Hot_Engine; Calculate the flow rate provided by the power system cooling loop: Q_Hot_Elec = Q_total * K_Hot_Elec; Calculate the flow rate supplied by the cryogenic coolant circuit: Q_Cold = 1 - Q_total * K_Cold; Traffic feedback control is implemented based on expected traffic volume.

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