Control method, system and vehicle for thermal management system safety

Abstract

The application provides a control method and system for safety of a thermal management system and a vehicle. The control method comprises: obtaining suction superheat of a compressor inlet and exhaust superheat of a compressor outlet; determining a refrigerant leakage level according to the suction superheat and the exhaust superheat; and controlling the speed of the compressor to be reduced, the opening of an expansion valve to be increased, and / or the speed of a cooling fan to be increased according to the leakage level, wherein the expansion valve is connected to a refrigerant inlet of a condenser. The application determines refrigerant leakage by using existing sensors of the thermal management system and a suitable algorithm, without increasing cost. The application controls the spread of leakage by controlling the actions of different components in the thermal management system, without increasing additional fans to perform protective measures, and has low cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of automobile thermal management system control, and particularly relates to a thermal management system safety control method and system and a vehicle. BACKGROUND

[0002] Based on the current industry demand for environmentally friendly refrigerants, various host manufacturers are actively working on the replacement of environmentally friendly refrigerants. Since R290 (propane) is a naturally occurring substance, its ODP (Ozone Depletion Potential) is 0, and its GWP (Global Warming Potential) is 0.03. It is a clean hydrocarbon refrigerant with superior thermophysical properties and is widely used as an ideal alternative refrigerant for electric vehicle heat pump systems. However, R290 has characteristics such as flammability and explosiveness, which are important factors limiting its development, leading to challenges in the large-scale application of R290 working medium. Therefore, how to prevent R290 thermal management system refrigerant leakage and eliminate the leakage method is particularly important. SUMMARY

[0003] In view of the above shortcomings of the prior art, the present application aims to provide a thermal management system safety control method and system and a vehicle to solve the problems of monitoring R290 thermal management system refrigerant leakage and eliminating R290 after leakage.

[0004] To achieve the above object and other related objects, the present application provides a thermal management system safety control method, comprising:

[0005] obtaining the suction superheat of the compressor inlet and the exhaust superheat of the outlet;

[0006] judging the refrigerant leakage level according to the suction superheat and the exhaust superheat;

[0007] controlling the reduction of the compressor speed, and / or the increase of the opening degree of the expansion valve, and / or the increase of the speed of the cooling fan according to the leakage level, wherein the expansion valve is connected at the refrigerant inlet of the condenser.

[0008] In an embodiment of the present application, the step of obtaining the suction superheat of the compressor inlet and the exhaust superheat of the outlet comprises:

[0009] obtaining the suction pipe temperature, the suction pipe pressure, the exhaust pipe temperature and the exhaust pipe pressure of the compressor;

[0010] obtaining the first refrigerant saturation temperature according to the suction pipe pressure;

[0011] obtaining the second refrigerant saturation temperature according to the exhaust pipe pressure;

[0012] the suction gas superheat degree is obtained according to the suction pipe temperature and the first refrigerant saturation temperature;

[0013] the discharge gas superheat degree is obtained according to the discharge pipe temperature and the second refrigerant saturation temperature.

[0014] In one embodiment of the present application, the step of controlling the compressor speed to decrease, and / or the expansion valve opening to increase, and / or the cooling fan speed to increase according to the refrigerant leakage level comprises:

[0015] Before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level rises, the compressor speed is gradually decreased, and / or the expansion valve opening is gradually increased until fully open, and / or the cooling fan speed is gradually increased until rotating at the maximum speed, wherein when the refrigerant leakage level rises to the highest, the compressor and the expansion valve are closed.

[0016] In one embodiment of the present application, the step of judging the refrigerant leakage level according to the suction gas superheat degree and the discharge gas superheat degree comprises:

[0017] when the first suction threshold < suction gas superheat degree ≤ second suction threshold, and the first discharge threshold < discharge gas superheat degree ≤ second discharge threshold, the refrigerant leakage level is the first leakage level;

[0018] when the second suction threshold < suction gas superheat degree ≤ third suction threshold, and the second discharge threshold < discharge gas superheat degree ≤ third discharge threshold, the refrigerant leakage level is the second leakage level;

[0019] when the suction gas superheat degree > third suction threshold, and the discharge gas superheat degree > third discharge threshold, the refrigerant leakage level is the third leakage level.

[0020] In one embodiment of the present application, the step of controlling the compressor speed to decrease, and / or the expansion valve opening to increase, and / or the cooling fan speed to increase according to the refrigerant leakage level comprises:

[0021] when the refrigerant leakage level is the first leakage level, the compressor is controlled to decrease the speed by a first preset threshold, and the expansion valve opening is controlled to the first preset opening;

[0022] when the refrigerant leakage level is the second leakage level, the compressor is controlled to decrease the speed by a second preset threshold, the expansion valve opening is controlled to the second preset opening, and the cooling fan is controlled to rotate at the maximum speed;

[0023] When the refrigerant leakage level is the third leakage level, the compressor and the expansion valve are controlled to be closed, and the cooling fan is controlled to rotate at the maximum speed.

[0024] In one embodiment of the present application, the control method further comprises: when the refrigerant leakage level is the third leakage level, a refrigerant leakage fault is sent and an alarm is given.

[0025] In one embodiment of the present application, after the action of reducing the speed of the compressor, and / or increasing the opening degree of the expansion valve, and / or increasing the speed of the cooling fan according to the current leakage level is completed, the method further comprises:

[0026] If the suction superheat degree and the discharge superheat degree increase within the first preset time, the refrigerant leakage level is controlled to jump to the corresponding leakage level, and the action of reducing the speed of the compressor, and / or increasing the opening degree of the expansion valve, and / or increasing the speed of the cooling fan to complete the action of the corresponding leakage level.

[0027] In one embodiment of the present application, after the action of reducing the speed of the compressor, and / or increasing the opening degree of the expansion valve, and / or increasing the speed of the cooling fan according to the current leakage level is completed, the method further comprises:

[0028] The suction superheat degree and the discharge superheat degree are acquired again after a second preset time interval;

[0029] If the suction superheat degree and the discharge superheat degree do not decrease, it is determined that the refrigerant leakage level increases, and jumps to the next leakage level;

[0030] The speed of the compressor is reduced, and / or the opening degree of the expansion valve is increased, and / or the speed of the cooling fan is increased according to the level of the next leakage level to complete the action of the corresponding level.

[0031] The present application also proposes a control system for the safety of the thermal management system of an electric vehicle, comprising:

[0032] A superheat degree acquisition module is configured to acquire the suction superheat degree at the inlet of the compressor and the discharge superheat degree at the outlet of the compressor.

[0033] A leakage level determination module is configured to determine the refrigerant leakage level according to the suction superheat degree and the discharge superheat degree.

[0034] A control module is configured to control the speed of the compressor to be reduced, and / or the opening degree of the expansion valve to be increased, and / or the speed of the cooling fan to be increased according to the leakage level, wherein the expansion valve is connected at the refrigerant inlet of the condenser.

[0035] The application also provides a vehicle comprising a thermal management system and a controller configured to control the thermal management system to implement the method for controlling safety of the thermal management system according to any one of the above embodiments.

[0036] The application provides a method and system for controlling safety of a thermal management system and a vehicle. The method comprises determining a leakage level of R290 refrigerant by monitoring suction superheat of a suction pipe and discharge superheat of a discharge pipe of a compressor, and reducing a local refrigerant accumulation concentration by using a corresponding control scheme. If the leakage level cannot be controlled within a certain time, the leakage can be controlled by upgrading the leakage level. The application uses existing sensors of the thermal management system and a suitable algorithm to determine the refrigerant leakage without increasing cost. The leakage can be controlled by controlling the operation of different components of the thermal management system without using additional fans to perform protective measures, thus reducing cost. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor.

[0038] Figure 1 A flowchart of a method for controlling safety of a thermal management system according to an embodiment of the application is shown.

[0039] Figure 2 A structure block diagram of a thermal management system according to an embodiment of the application is shown.

[0040] Figure 3 A flowchart of a method for obtaining superheat according to an embodiment of the application is shown.

[0041] Figure 4 A structure block diagram of a control system for safety of an electric vehicle thermal management system according to an embodiment of the application is shown. DETAILED DESCRIPTION

[0042] The embodiments of the application are described below through specific and concrete examples. Those skilled in the art can easily understand other advantages and effects of the application from the disclosure. The application can also be implemented or applied through different specific embodiments, and the details in the description can be modified or changed based on different views and applications without departing from the spirit of the application.

[0043] It should be noted that the diagrams provided in the embodiments only schematically illustrate the basic concepts of the present application, and only the components related to the present application are shown in the diagrams, rather than being drawn according to the number, shape and size of the components in actual implementation. The shapes, number and proportions of the components in actual implementation can be arbitrarily changed, and the layout pattern of the components can be more complex.

[0044] Please refer to Figure 1 The present application provides a control method and system for the safety of a thermal management system and a vehicle to solve the problems of monitoring the leakage of R290 refrigerant in the thermal management system and eliminating the leaked R290. For example, in the prior art, the R290 refrigerant side components are integrated into one body, wrapped with a metal shell on the outside, and a separate electronic fan is provided. If leakage occurs, the fan is started to blow away the refrigerant to reduce the local concentration. However, this solution has the problems of high cost, large space occupation and difficult application. Therefore, the present application provides a control method for the safety of a thermal management system, as shown in Figure 1 and Figure 2 The present application provides a control method for the safety of a thermal management system, as shown in Figure 1 The present application provides a control method for the safety of a thermal management system, as shown in Figure 2 The present application provides a control method for the safety of a thermal management system, as shown in

[0045] S1, obtaining the suction superheat degree at the inlet of the compressor and the discharge superheat degree at the outlet of the compressor;

[0046] Please refer to Figure 3 The present application provides a control method for the safety of a thermal management system, as shown in Figure 3 The present application provides a control method for the safety of a thermal management system, as shown in

[0047] S11, obtaining the suction pipe temperature, suction pipe pressure, discharge pipe temperature and discharge pipe pressure of the compressor; For example, the suction pipe temperature, suction pipe pressure, discharge pipe temperature and discharge pipe pressure of the compressor can be detected by the temperature sensor and pressure sensor of the thermal management system itself, without the need for additional components, excessive space occupation, cost reduction and application difficulty.

[0048] S12, obtaining the first refrigerant saturation temperature according to the suction pipe pressure;

[0049] S13, obtaining a second refrigerant saturation temperature according to the exhaust pipe pressure;

[0050] It can be understood that the refrigerant saturation temperature refers to the temperature at which the refrigerant changes from liquid to gas or from gas to liquid at a certain pressure, which can be directly determined by the pressure of the refrigerant and the corresponding saturation curve (such as the vapor pressure curve of the refrigerant).

[0051] S14, obtaining the suction superheat according to the suction pipe temperature and the first refrigerant saturation temperature, wherein the suction superheat is the difference between the suction pipe temperature and the first refrigerant saturation temperature.

[0052] S15, obtaining the exhaust superheat according to the exhaust pipe temperature and the second refrigerant saturation temperature, wherein the exhaust superheat is the difference between the exhaust pipe temperature and the second refrigerant saturation temperature.

[0053] It can be understood that in the present embodiment, steps S12 and S13 are not sequential and can be performed simultaneously, and steps S14 and S15 are not sequential and can be performed simultaneously.

[0054] S2, determining the refrigerant (R290) leakage level according to the suction superheat and the exhaust superheat, wherein the higher the refrigerant leakage level, the more serious the refrigerant leakage.

[0055] S3, controlling the reduction of the compressor speed, and / or the increase of the opening degree of the expansion valve connected at the refrigerant inlet of the condenser, and / or the increase of the rotation speed of the cooling fan according to the leakage level. It can be understood that the expansion valve is connected at the refrigerant inlet of the condenser, i.e. the expansion valve is connected between the refrigerant inlet of the condenser and the outlet of the liquid storage tank, the flow of refrigerant entering the condenser can be controlled by controlling the opening degree of the expansion valve, and the flow and speed of refrigerant entering the compressor can be controlled by reducing the rotation speed of the compressor to control the spread of leakage, and the local concentration of refrigerant (R290) can be reduced by controlling the rotation speed of the cooling fan to ensure safety when leakage occurs.

[0056] Specifically, in the present embodiment, the step of controlling the reduction of the compressor speed, the opening degree of the expansion valve, and the rotation speed of the cooling fan according to the leakage level comprises:

[0057] Before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level rises, gradually reduce the speed of the compressor, and / or gradually increase the opening of the expansion valve until fully open, and / or gradually increase the speed of the cooling fan until rotating at the maximum speed, wherein when the refrigerant leakage level rises to the highest, the compressor and the expansion valve are closed, that is, the more serious the refrigerant leakage, the lower the speed of the compressor, the larger the opening of the expansion valve, and the faster the speed of the cooling fan, and each leakage level can correspond to a compressor speed, an expansion valve opening, and a cooling fan speed, so that when a refrigerant leakage event occurs, the controller can control the compressor, the expansion valve, and the cooling fan in the system to perform corresponding actions at each refrigerant leakage level, to control the spread of leakage and reduce the local concentration of refrigerant (R290), wherein when the refrigerant leakage level rises to the highest, the compressor and the expansion valve are closed, and the system stops running, while the cooling fan continues to rotate to reduce the local concentration of refrigerant.

[0058] Please refer to Figure 1 In the embodiment, the refrigerant leakage level can be divided into three levels, namely the first leakage level, the second leakage level, and the third leakage level. Specifically, the refrigerant leakage level is determined according to the suction superheat and the discharge superheat, which includes:

[0059] When the first suction threshold < suction superheat ≤ second suction threshold, and the first discharge threshold < discharge superheat ≤ second discharge threshold, the refrigerant leakage level is the first leakage level;

[0060] When the second suction threshold < suction superheat ≤ third suction threshold, and the second discharge threshold < discharge superheat ≤ third discharge threshold, the refrigerant leakage level is the second leakage level;

[0061] When the suction superheat > third suction threshold, and the discharge superheat > third discharge threshold, the refrigerant leakage level is the third leakage level.

[0062] In the embodiment, the first suction threshold, the first suction threshold, and the third suction threshold are 20, 30, and 40 respectively, and the first discharge threshold, the second suction threshold, and the third discharge threshold are 40, 50, and 60 respectively. Of course, in some other embodiments, the above thresholds can be set to other values as needed. It can be understood that the refrigerant leakage level can also be subdivided into more leakage levels, and corresponding suction thresholds and discharge thresholds can be set to achieve more subdivided leakage level determination.

[0063] Please refer to Figure 1As shown, the step of controlling the compressor to reduce the rotation speed, and / or controlling the expansion valve to increase the opening degree, and / or controlling the cooling fan to increase the rotation speed according to the refrigerant leakage level comprises:

[0064] When the refrigerant leakage level is the first leakage level, the compressor is controlled to reduce the rotation speed by a first preset threshold, and the opening degree of the expansion valve is controlled to a first preset opening degree, and the system operates normally;

[0065] When the refrigerant leakage level is the second leakage level, the compressor is controlled to reduce the rotation speed by a second preset threshold, the opening degree of the expansion valve is controlled to a second preset opening degree, and the cooling fan is controlled to rotate at the maximum rotation speed, and the system operates normally;

[0066] When the refrigerant leakage level is the third leakage level, the compressor and the expansion valve are controlled to be closed, and the cooling fan is controlled to rotate at the maximum rotation speed.

[0067] Referring to Figure 1 As shown, in the embodiment, the control method further comprises: when the refrigerant leakage level is the third leakage level, a refrigerant leakage fault is sent and an alarm is given to remind the user, so as to ensure safety.

[0068] It can be understood that, in the embodiment, the first preset threshold in the first leakage level and the second preset threshold in the second leakage level are in the range of 1000 rpm to 3000 rpm, and the first preset threshold and the second preset threshold can be the same or different, and when in the first leakage level, the rotation speed of the compressor is controlled to reduce by the first preset threshold, and when the leakage level rises from the first leakage level to the second leakage level, the rotation speed of the compressor is controlled to reduce by the second preset threshold again on the basis of reducing by the first preset threshold. It can also be understood that the second preset opening degree is greater than the first preset opening degree, so that the opening degree of the expansion valve gradually increases as the leakage level rises until the opening degree reaches 100%, for example, the first preset opening degree is 80%, and the second preset opening degree is 100%.

[0069] Referring to Figure 1 As shown, in the embodiment, after the action of controlling the compressor to reduce the rotation speed, and / or controlling the expansion valve to increase the opening degree, and / or controlling the cooling fan to increase the rotation speed according to the current leakage level is completed, the method further comprises:

[0070] If the suction superheat and the discharge superheat increase within the first preset time, the refrigerant leakage level is controlled to jump to a corresponding leakage level, and the actions of decreasing the rotation speed of the compressor, and / or increasing the opening degree of the expansion valve, and / or increasing the rotation speed of the cooling fan to complete the actions of the corresponding leakage level are controlled. For example, in the present embodiment, when the actions of decreasing the rotation speed of the compressor by the first preset threshold value and controlling the opening degree of the expansion valve to 80% are completed according to the first leakage level control, if the suction superheat and the discharge superheat increase within 1 minute after the actions are completed, the refrigerant leakage level is controlled to jump to the second leakage level, and the rotation speed of the compressor is decreased by the second preset threshold value, the opening degree of the expansion valve is controlled to the second preset opening degree, and the cooling fan is controlled to rotate at the maximum rotation speed.

[0071] Referring to Figure 1 In the present embodiment, after the actions of decreasing the rotation speed of the compressor, and / or increasing the opening degree of the expansion valve, and / or increasing the rotation speed of the cooling fan to complete the actions according to the current leakage level control, the method further comprises:

[0072] The suction superheat and the discharge superheat are acquired again after a second preset time interval;

[0073] If the suction superheat and the discharge superheat do not decrease, it is determined that the refrigerant leakage level increases, and jumps to the next leakage level;

[0074] The rotation speed of the compressor, and / or the opening degree of the expansion valve, and / or the rotation speed of the cooling fan are controlled to complete the actions according to the level of the next leakage level.

[0075] For example, after the actions of decreasing the rotation speed of the compressor, the opening degree of the expansion valve, and the rotation speed of the cooling fan are completed according to the first leakage level control, the suction superheat and the discharge superheat are acquired again, for example, after an interval of 5 minutes. If the suction superheat and the discharge superheat do not decrease from the suction superheat and the discharge superheat when the first leakage level, it is determined that the refrigerant leakage level increases, and jumps to the second leakage level, and the rotation speed of the compressor, the opening degree of the expansion valve, and the rotation speed of the cooling fan are controlled to complete the actions according to the second leakage level.

[0076] It can be understood that the second preset time is greater than the first preset time, that is, if the suction superheat and the exhaust superheat increase within the first preset time, the refrigerant leakage level is controlled to jump to the corresponding leakage level, at this time, it is not necessary to wait for the second preset time to obtain the suction superheat and the exhaust superheat again, and it is judged whether it decreases; if the suction superheat and the exhaust superheat do not increase within the first preset time, after the action of controlling to reduce the rotation speed of the compressor, the opening of the expansion valve, and the rotation speed of the cooling fan according to the current leakage level is completed, the suction superheat and the exhaust superheat are obtained again after the second preset time, and it is judged whether it decreases, if it does not decrease, the refrigerant leakage level is controlled to increase, and jumps to the next leakage level.

[0077] Please refer to Figure 4 shown, Figure 4 A structure block diagram of a control system for safety of an electric vehicle thermal management system in the embodiment of the application is shown. In the embodiment, a control system for safety of an electric vehicle thermal management system is provided, which corresponds to the control method for safety of a thermal management system in the above embodiment. Specifically, the control system for safety of an electric vehicle thermal management system 100 comprises a superheat obtaining module 10, a leakage level determining module 20 and a control module 30, and each functional module is described in detail as follows:

[0078] The superheat obtaining module 10 is used to obtain the suction superheat of the compressor inlet and the exhaust superheat of the outlet; specifically, the superheat obtaining module 10 comprises a temperature detecting unit 11, a pressure detecting unit 12, a refrigerant saturation temperature obtaining unit 13 and a superheat calculating unit 14, specifically,

[0079] The temperature detecting unit 11 is used to obtain the suction pipe temperature and the exhaust pipe temperature of the compressor; for example, the temperature detecting unit 11 is a temperature sensor of the thermal management system itself, which is located at the suction pipe position and the exhaust pipe position of the compressor.

[0080] The pressure detecting unit 12 is used to obtain the suction pipe pressure and the exhaust pipe pressure of the compressor; for example, the pressure detecting unit 12 is a pressure sensor of the thermal management system itself, which is located at the suction pipe position and the exhaust pipe position of the compressor.

[0081] The refrigerant saturation temperature obtaining unit 13 is used to obtain the first refrigerant saturation temperature according to the suction pipe pressure, and the second refrigerant saturation temperature according to the exhaust pipe pressure; the refrigerant saturation temperature obtaining unit 13 obtains the first refrigerant saturation temperature and the first refrigerant saturation temperature according to the suction pipe pressure, the exhaust pipe pressure and the pressure and saturation curve of the corresponding refrigerant.

[0082] The superheat degree calculation unit 14 is configured to obtain the suction superheat degree according to the suction pipe temperature and the first refrigerant saturation temperature, and obtain the discharge superheat degree according to the discharge pipe temperature and the second refrigerant saturation temperature.

[0083] The leakage level determination module 20 is configured to determine the refrigerant leakage level according to the suction superheat degree and the discharge superheat degree; in particular, the leakage level determination module 20 determines the refrigerant (R290) leakage level according to the value of the suction superheat degree and the value of the discharge superheat degree, wherein the higher the refrigerant leakage level, the more serious the refrigerant leakage.

[0084] The control module 30 is configured to control the compressor speed to be reduced, and / or the opening degree of the expansion valve to be increased, and / or the cooling fan speed to be increased according to the leakage level, wherein the expansion valve is connected at the refrigerant inlet of the condenser; in particular, as the refrigerant leakage level increases, the control module 30 controls the compressor speed to be gradually reduced until the compressor is turned off, the opening degree of the expansion valve to be gradually increased until the expansion valve is fully opened, and the cooling fan speed to be gradually increased until the cooling fan rotates at the maximum speed.

[0085] The specific limitations of the control system for the safety of the electric vehicle thermal management system can refer to the limitations of the control method for the safety of the thermal management system described above, which will not be repeated here. Each module in the control system for the safety of the electric vehicle thermal management system can be realized by software, hardware, or a combination thereof. Each module described above can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0086] Please refer to Figure 1 The present application also provides a vehicle, which comprises a thermal management system and a controller, wherein the controller is configured to control the thermal management system to implement the control method for the safety of the thermal management system according to any one of the above embodiments, and specifically implement the following steps:

[0087] obtain the suction superheat degree at the compressor inlet and the discharge superheat degree at the outlet;

[0088] determine the refrigerant leakage level according to the suction superheat degree and the discharge superheat degree;

[0089] control the compressor speed to be reduced, and / or the opening degree of the expansion valve to be increased, and / or the cooling fan speed to be increased according to the leakage level, wherein the expansion valve is connected at the refrigerant inlet of the condenser.

[0090] The application provides a control method and system for safety of a thermal management system and a vehicle. The control method comprises the following steps: monitoring suction overheating degree of a suction pipe of a compressor and exhaust overheating degree of an exhaust pipe; determining a leakage level of R290 refrigerant; and adopting a corresponding control scheme to reduce a local refrigerant accumulation concentration. Meanwhile, if the refrigerant leakage degree cannot be controlled within a certain time, the leakage spreading can be controlled by upgrading the leakage level. The application uses existing sensors of the existing thermal management system and a suitable algorithm to determine the refrigerant leakage without increasing the cost. The spreading of the leakage is controlled by controlling the actions of different components of the thermal management system without increasing an additional fan to perform a protection measure, and the cost is low.

[0091] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

[0092] In addition to the technical features described in the specification, the remaining technical features are known to those skilled in the art, and in order to highlight the innovative features of the present application, the remaining technical features are not described here.

Claims

1. A control method of thermal management system safety, characterized by, In the heat management system, the compressor, the LCC heat exchanger, the liquid storage tank, the expansion valve, the condenser and the compressor are connected in sequence, comprising: obtaining the suction superheat of the compressor inlet and the exhaust superheat of the outlet; determining the refrigerant leakage level according to the suction superheat and the exhaust superheat; controlling the opening of the expansion valve to increase according to the leakage level, wherein the expansion valve is connected at the refrigerant inlet of the condenser; the step of controlling the opening of the expansion valve to increase according to the leakage level comprises: before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level rises, the opening of the expansion valve is gradually increased until it is fully opened, and when the refrigerant leakage level rises to the highest, the compressor and the expansion valve are closed.

2. The control method of thermal management system safety according to claim 1, characterized in that, The control method further comprises: controlling the speed of the compressor to decrease according to the leakage level, comprising: before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level rises, the speed of the compressor is gradually reduced, and when the refrigerant leakage level rises to the highest, the compressor is closed; and / or, controlling the speed of the cooling fan to increase according to the leakage level, comprising: before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level rises, the speed of the cooling fan is gradually increased until it rotates at the maximum speed.

3. The control method of thermal management system safety according to claim 1, characterized in that, The step of obtaining the suction superheat of the compressor inlet and the exhaust superheat of the outlet comprises: obtaining the suction pipe temperature, the suction pipe pressure, the exhaust pipe temperature and the exhaust pipe pressure of the compressor; obtaining the first refrigerant saturation temperature according to the suction pipe pressure; obtaining the second refrigerant saturation temperature according to the exhaust pipe pressure; obtaining the suction superheat according to the suction pipe temperature and the first refrigerant saturation temperature; obtaining the exhaust superheat according to the exhaust pipe temperature and the second refrigerant saturation temperature.

4. The control method of thermal management system safety according to claim 2, characterized in that, The step of determining the refrigerant leakage level according to the suction superheat and the exhaust superheat comprises: when the first suction threshold < suction superheat ≤ second suction threshold, and the first exhaust threshold < exhaust superheat ≤ second exhaust threshold, the refrigerant leakage level is the first leakage level; when the second suction threshold < suction superheat ≤ third suction threshold, and the second exhaust threshold < exhaust superheat ≤ third exhaust threshold, the refrigerant leakage level is the second leakage level; when the suction superheat > third suction threshold, and the exhaust superheat > third exhaust threshold, the refrigerant leakage level is the third leakage level.

5. The control method of thermal management system safety according to claim 4, characterized in that, The step of controlling the opening of the expansion valve to increase according to the leakage level, or, controlling the opening of the expansion valve to increase according to the leakage level, and controlling the speed of the compressor to decrease and / or controlling the speed of the cooling fan to increase comprises: when the refrigerant leakage level is the first leakage level, the speed of the compressor is controlled to decrease by a first preset threshold, and the opening of the expansion valve is controlled to the first preset opening; When the refrigerant leakage level is the second leakage level, the compressor is controlled to reduce the rotation speed of a second preset threshold, the opening degree of the expansion valve is controlled to a second preset opening degree, and the cooling fan is controlled to rotate at the maximum rotation speed; When the refrigerant leakage level is the third leakage level, the compressor and the expansion valve are controlled to be closed, and the cooling fan is controlled to rotate at the maximum rotation speed.

6. The control method of thermal management system safety according to claim 4, characterized in that, The control method further comprises: when the refrigerant leakage level is the third leakage level, a refrigerant leakage fault is sent and an alarm is given.

7. The control method of thermal management system safety according to claim 2, characterized in that, After the action of controlling to increase the opening degree of the expansion valve according to the leakage level, or, controlling to increase the opening degree of the expansion valve according to the leakage level, and controlling to reduce the rotation speed of the compressor and / or controlling to increase the rotation speed of the cooling fan is completed, the method further comprises: If the suction superheat degree and the discharge superheat degree increase within a first preset time, the refrigerant leakage level is controlled to jump to a corresponding leakage level, and the action of completing the corresponding leakage level by controlling to reduce the rotation speed of the compressor, to increase the opening degree of the expansion valve, and to increase the rotation speed of the cooling fan is completed.

8. The control method of thermal management system safety according to claim 2, characterized in that, After the action of controlling to increase the opening degree of the expansion valve according to the leakage level, or, controlling to increase the opening degree of the expansion valve according to the leakage level, and controlling to reduce the rotation speed of the compressor and / or controlling to increase the rotation speed of the cooling fan is completed, the method further comprises: The suction superheat degree and the discharge superheat degree are acquired again after a second preset time; If the suction superheat degree and the discharge superheat degree do not decrease, it is determined that the refrigerant leakage level is raised, and jumps to a next leakage level; The action of completing the corresponding level by controlling to increase the opening degree of the expansion valve according to the level of the next leakage level, or, controlling to increase the opening degree of the expansion valve according to the next leakage level, and controlling to reduce the rotation speed of the compressor and / or controlling to increase the rotation speed of the cooling fan is completed.

9. A control system for safety of an electric vehicle thermal management system, characterized by, In the thermal management system, the compressor, the LCC heat exchanger, the liquid storage tank, the expansion valve, the condenser and the compressor are connected in sequence, comprising: A superheat degree acquisition module is configured to acquire a suction superheat degree at the inlet of the compressor and a discharge superheat degree at the outlet of the compressor; A leakage level determination module is configured to determine a refrigerant leakage level according to the suction superheat degree and the discharge superheat degree; A control module is configured to control to increase the opening degree of the expansion valve according to the leakage level, wherein the expansion valve is connected at the refrigerant inlet of the condenser; the control to increase the opening degree of the expansion valve according to the leakage level comprises: Before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level rises, the opening degree of the expansion valve is gradually increased until fully opened, wherein when the refrigerant leakage level rises to the highest, the compressor and the expansion valve are closed.

10. The control system for safety of electric vehicle thermal management system according to claim 9, wherein, The control module is further configured to control to reduce the rotation speed of the compressor according to the leakage level, comprising: before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level rises, the rotation speed of the compressor is gradually reduced, wherein when the refrigerant leakage level rises to the highest, the compressor is closed; and / or, The control module is further configured to control the rotation speed of the cooling fan to increase according to the leakage level, including: before the refrigerant leakage level rises to the highest leakage level, gradually increasing the rotation speed of the cooling fan until rotating at the maximum rotation speed as the refrigerant leakage level rises.

11. A vehicle characterized by comprising: The vehicle comprises a thermal management system and a controller configured to control the thermal management system to implement the control method of the thermal management system safety according to any one of claims 1 to 8.

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