Thermal management system safety control method and system and vehicle

Abstract

The invention provides a thermal management system safety control method and system and a vehicle. The control method comprises the steps that the suction superheat degree of an inlet of a compressor and the exhaust superheat degree of an outlet of the compressor are obtained; the refrigerant leakage grade is judged according to the suction superheat degree and the exhaust superheat degree; according to the leakage grade, the rotating speed of a compressor is controlled to be reduced, and / or the opening degree of an expansion valve is increased, and / or the rotating speed of a cooling fan is increased, and the expansion valve is connected to a refrigerant inlet of a condenser. According to the method, the refrigerant leakage is judged by utilizing the existing sensor of the existing thermal management system and through a proper algorithm, the cost does not need to be increased, meanwhile, the spreading of the leakage is controlled by controlling the actions of different parts in the thermal management system, an additional fan does not need to be added to execute protective measures, and the cost is relatively low.

Description

Technical Field

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

[0002] Based on the current industry demand for the use of environmentally friendly refrigerants, various OEMs are currently 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 excellent thermophysical properties and is widely used as an ideal alternative refrigerant for electric vehicle heat pump systems. However, the flammable and explosive characteristics of R290 are important factors restricting its development, resulting in challenges to the large-scale application of R290 working fluids. Therefore, how to prevent refrigerant leakage in the R290 thermal management system and how to eliminate leakage are particularly important. Summary of the invention

[0003] In view of the above shortcomings of the prior art, the purpose of the present invention is to provide a thermal management system safety control method, system and vehicle to solve the problem of monitoring refrigerant leakage in the R290 thermal management system and how to eliminate the leaked R290.

[0004] To achieve the above-mentioned purpose and other related purposes, the present invention provides a control method for the safety of a thermal management system, comprising:

[0005] Obtain the suction superheat at the compressor inlet and the exhaust superheat at the compressor outlet;

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

[0007] The rotation speed of the compressor is reduced according to the leakage level control, and / or the opening of the expansion valve is increased, and / or the rotation speed of the cooling fan is increased, wherein the expansion valve is connected to the refrigerant inlet of the condenser.

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

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

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

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

[0012] Acquire the suction superheat according to the suction pipe temperature and the first refrigerant saturation temperature;

[0013] The exhaust superheat is obtained according to the exhaust pipe temperature and the second refrigerant saturation temperature.

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

[0015] Before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level increases, the speed of the compressor is controlled to gradually decrease, and / or the opening of the expansion valve is controlled to gradually increase until it is fully opened, and / or the speed of the cooling fan is controlled to gradually increase until it rotates 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 invention, judging the refrigerant leakage level according to the suction superheat and the exhaust superheat comprises:

[0017] When the first suction threshold value is less than the suction superheat degree ≤ the second suction threshold value, and the first exhaust threshold value is less than the exhaust superheat degree ≤ the second exhaust threshold value, the refrigerant leakage level is the first leakage level;

[0018] When the second suction threshold value is less than the suction superheat degree ≤ the third suction threshold value, and the second exhaust threshold value is less than the exhaust superheat degree ≤ the third exhaust threshold value, the refrigerant leakage level is the second leakage level;

[0019] When the suction superheat degree is greater than the third suction threshold value, and the discharge superheat degree is greater than the third discharge threshold value, the refrigerant leakage level is the third leakage level.

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

[0021] When the refrigerant leakage level is a first leakage level, controlling the compressor to reduce the rotation speed of a first preset threshold value, and controlling the opening of the expansion valve to a first preset opening;

[0022] When the refrigerant leakage level is a second leakage level, controlling the compressor to reduce the speed of the second preset threshold, controlling the opening of the expansion valve to a second preset opening, and controlling the cooling fan to rotate at a maximum speed;

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

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

[0025] In one embodiment of the present invention, after the actions of reducing the speed of the compressor and / or increasing the opening of the expansion valve and / or increasing the speed of the cooling fan according to the current leakage level are completed, the method further includes:

[0026] 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, and the compressor speed is controlled to be reduced, and / or the opening of the expansion valve is increased, and / or the speed of the cooling fan is increased to complete the corresponding leakage level action.

[0027] In one embodiment of the present invention, after the actions of reducing the speed of the compressor and / or increasing the opening of the expansion valve and / or increasing the speed of the cooling fan according to the current leakage level are completed, the method further includes:

[0028] Obtaining the suction superheat and the exhaust superheat again after a second preset time interval;

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

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

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

[0032] A superheat acquisition module is used to obtain the suction superheat at the compressor inlet and the exhaust superheat at the outlet;

[0033] A leakage level determination module, used for determining the refrigerant leakage level according to the suction superheat and the exhaust superheat;

[0034] A control module is used to control the reduction of the speed of the compressor and / or increase the opening of the expansion valve and / or increase the speed of the cooling fan according to the leakage level, wherein the expansion valve is connected to the refrigerant inlet of the condenser.

[0035] The present invention further proposes a vehicle, comprising a thermal management system and a controller, wherein the controller is used to control the thermal management system to implement a thermal management system safety control method as described in any one of the above embodiments.

[0036] The present invention proposes a control method, system and vehicle for the safety of a thermal management system, which determine the leakage level of R290 refrigerant by monitoring the suction superheat of the compressor suction pipe and the exhaust superheat of the exhaust pipe, so as to adopt a corresponding control scheme to reduce the local refrigerant accumulation concentration; at the same time, if the refrigerant leakage level cannot be controlled within a certain period of time, the spread of the leakage can be controlled by upgrading the leakage level; the present application utilizes the existing sensors of the existing thermal management system and uses a suitable algorithm to determine the refrigerant leakage without increasing the cost, and at the same time controls the spread of the leakage by controlling the actions of different components in the thermal management system, without adding additional fans to implement protective measures, and the cost is relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0038] Figure 1 Shown is a flow chart of a method for controlling the safety of a thermal management system in one embodiment of the present application.

[0039] Figure 2 Shown is a structural block diagram of a thermal management system in one embodiment of the present application.

[0040] Figure 3 Shown is a schematic diagram of a process for obtaining superheat in one embodiment of the present application.

[0041] Figure 4 Shown is a structural block diagram of a control system for the safety of an electric vehicle thermal management system in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0043] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0044] See also Figure 1 As shown, the present invention proposes a control method, system and vehicle for the safety of a thermal management system to solve the problem of monitoring the refrigerant leakage of the R290 thermal management system and how to eliminate the R290 after the leakage. For example, in the prior art, by integrating the R290 refrigerant side components into one, and wrapping them with a metal shell on the outside and setting a separate electronic fan, if there is a leak, the fan is started to blow away the refrigerant to reduce the local concentration, but this solution has the problems of high cost, large space occupation and high application difficulty. Therefore, the present application provides a control method for the safety of a thermal management system, please refer to Figure 1 and Figure 2 As shown, Figure 1 Shown is a flow chart of a method for controlling the safety of a thermal management system in one embodiment of the present application; Figure 2 The structure block diagram of the thermal management system in one embodiment of the present application is shown, which uses existing sensors in the existing thermal management system and uses appropriate algorithms to determine refrigerant leakage, and at the same time controls the actions of different components in the thermal management system to control the spread of the leakage, so as to solve the problems in the prior art and achieve the purpose of monitoring the refrigerant leakage of the R290 thermal management system and eliminating the R290 after the leakage. In this embodiment, the control method of the safety of the thermal management system includes the following steps:

[0045] S1, obtaining the suction superheat at the compressor inlet and the exhaust superheat at the compressor outlet;

[0046] See also Figure 3 As shown, Figure 3 The flowchart of obtaining superheat in one embodiment of the present application is shown. Specifically, the steps of obtaining the suction superheat at the compressor inlet and the exhaust superheat at the outlet include:

[0047] S11. Obtaining the suction pipe temperature, suction pipe pressure, exhaust pipe temperature and exhaust pipe pressure of the compressor; for example, the suction pipe temperature, suction pipe pressure, exhaust pipe temperature and exhaust pipe pressure of the compressor can be detected by the temperature sensor and pressure sensor of the thermal management system itself, without adding additional parts, without occupying too much space, reducing costs and application difficulty.

[0048] S12, obtaining a 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 under a specific pressure. This temperature can be directly determined by the refrigerant pressure and the corresponding saturation curve (such as the refrigerant vapor pressure curve).

[0051] S14. Obtaining the suction superheat according to the suction pipe temperature and the first refrigerant saturation temperature, wherein the suction superheat is a 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 this embodiment, step S12 and step S13 can be performed in any order and can be performed simultaneously, and step S14 and step S15 can be performed in any order and can be performed simultaneously.

[0054] S2. Determine the refrigerant leakage level according to the suction superheat and the exhaust superheat. In step S2, determine 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. According to the leakage level, the speed of the compressor is reduced, and / or the opening of the expansion valve is increased, and / or the speed of the cooling fan is increased, wherein the expansion valve is connected to the refrigerant inlet of the condenser. It is understandable that the expansion valve is connected to the refrigerant inlet of the condenser, that is, the expansion valve is connected between the refrigerant inlet of the condenser and the outlet of the liquid storage tank, and the flow rate of the refrigerant entering the condenser can be controlled by controlling the opening of the expansion valve, and the flow rate and speed of the refrigerant entering the compressor can be controlled by reducing the speed of the compressor to control the spread of the leakage, and the local concentration of the refrigerant (R290) can be reduced by controlling the speed of the cooling fan, thereby ensuring safety when leakage occurs.

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

[0057] Before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level increases, the speed of the compressor is controlled to gradually decrease, and / or the opening of the expansion valve is controlled to gradually increase until it is fully opened, and / or the speed of the cooling fan is controlled to gradually increase until it rotates 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 is, 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 perform corresponding actions on the compressor, the expansion valve, and the cooling fan in the thermal management system at each refrigerant leakage level to control the spread of the leakage and reduce the local concentration of the refrigerant (R290), wherein, when the refrigerant leakage level rises to the highest, the compressor and the expansion valve are closed, the system stops running, and the cooling fan continues to rotate to reduce the local refrigerant concentration.

[0058] See also Figure 1 As shown, in this embodiment, the refrigerant leakage level can be divided into three levels, namely, a first leakage level, a second leakage level and a third leakage level. Specifically, judging the refrigerant leakage level according to the suction superheat and the exhaust superheat includes:

[0059] When the first suction threshold value is less than the suction superheat degree ≤ the second suction threshold value, and the first exhaust threshold value is less than the exhaust superheat degree ≤ the second exhaust threshold value, the refrigerant leakage level is the first leakage level;

[0060] When the second suction threshold value is less than the suction superheat degree ≤ the third suction threshold value, and the second exhaust threshold value is less than the exhaust superheat degree ≤ the third exhaust threshold value, the refrigerant leakage level is the second leakage level;

[0061] When the suction superheat degree is greater than a third suction threshold value, and the discharge superheat degree is greater than a third discharge threshold value, the refrigerant leakage level is the third leakage level.

[0062] In this embodiment, the first air intake threshold, the first air intake threshold and the third air intake threshold are 20, 30 and 40 respectively, and the first air exhaust threshold, the second air intake threshold and the third air exhaust 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 be further subdivided into more leakage levels, and the corresponding air intake threshold and air exhaust threshold are set to achieve a more subdivided leakage level determination.

[0063] See also Figure 1As shown, the step of controlling to reduce the speed of the compressor according to the leakage level, and / or increasing the opening of the expansion valve, and / or increasing the speed of the cooling fan includes:

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

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

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

[0067] See also Figure 1 As shown, in this embodiment, the control method further includes: when the refrigerant leakage level is the third leakage level, a refrigerant leakage fault is sent and an alarm is issued to remind the user, thereby ensuring safety.

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

[0069] See also Figure 1 As shown, in this embodiment, after the actions of reducing the speed of the compressor according to the current leakage level control, and / or increasing the opening of the expansion valve, and / or increasing the speed of the cooling fan are completed, the method further includes:

[0070] Within the first preset time, if the suction superheat and the exhaust superheat increase, the refrigerant leakage level is controlled to jump to the corresponding leakage level, and the corresponding leakage level is completed by reducing the speed of the compressor, and / or increasing the opening of the expansion valve, and / or increasing the speed of the cooling fan. For example, in this embodiment, after the action of controlling the compressor to reduce the speed to the first preset threshold value and controlling the opening of the expansion valve to 80% according to the first leakage level is completed, within 1 minute after the action is completed, if the suction superheat and the exhaust superheat increase, the refrigerant leakage level is controlled to jump to the second leakage level, and the compressor is controlled to reduce the speed of the second preset threshold value, the opening of the expansion valve is controlled to the second preset opening, and the cooling fan is controlled to rotate at the maximum speed.

[0071] See also Figure 1 As shown, in this embodiment, after the actions of reducing the speed of the compressor according to the current leakage level control, and / or increasing the opening of the expansion valve, and / or increasing the speed of the cooling fan are completed, the method further includes:

[0072] Obtaining the suction superheat and the exhaust superheat again after a second preset time interval;

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

[0074] According to the level of the next leakage level, the speed of the compressor is controlled to be reduced, and / or the opening of the expansion valve is increased, and / or the speed of the cooling fan is increased to complete the action of the corresponding level.

[0075] For example, after the action of reducing the speed of the compressor, the opening of the expansion valve, and the speed of the cooling fan according to the first leakage level control is completed, the suction superheat and the exhaust superheat are obtained again, for example, at an interval of 5 minutes. If the suction superheat and the exhaust superheat do not decrease when they were at the first leakage level, it is determined that the refrigerant leakage level has increased, and it jumps to the second leakage level, and according to the second leakage level, the speed of the compressor, the opening of the expansion valve, and the speed of the cooling fan are controlled to be reduced to complete the action of the corresponding 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, and there is no need to wait for the second preset time to obtain the suction superheat and the exhaust superheat again, and judge whether they have decreased; if the suction superheat and the exhaust superheat do not increase within the first preset time, then after the action of controlling the reduction of the compressor speed, the opening of the expansion valve, and the cooling fan speed according to the current leakage level is completed, the suction superheat and the exhaust superheat are obtained again at an interval of the second preset time, and it is judged whether they have decreased. If not, the refrigerant leakage level is controlled to increase and jump to the next leakage level.

[0077] See also Figure 4 As shown, Figure 4 The structure block diagram of the control system for the safety of the thermal management system of an electric vehicle in the embodiment of the present application is shown. In this embodiment, a control system for the safety of the thermal management system of an electric vehicle is provided, and the control system for the safety of the thermal management system of an electric vehicle corresponds one-to-one with the control method for the safety of the thermal management system in the above embodiment. Specifically, the control system 100 for the safety of the thermal management system of an electric vehicle includes an overheat acquisition module 10, a leakage level determination module 20 and a control module 30, and each functional module is described in detail as follows:

[0078] The superheat acquisition module 10 is used to obtain the suction superheat at the compressor inlet and the exhaust superheat at the outlet; specifically, the superheat acquisition module 10 includes a temperature detection unit 11, a pressure detection unit 12, a refrigerant saturation temperature acquisition unit 13 and a superheat calculation unit 14. Specifically,

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

[0080] The pressure detection unit 12 is used to obtain the suction pipe pressure and the exhaust pipe pressure of the compressor; for example, the pressure detection 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 acquisition unit 13 is used to obtain the first refrigerant saturation temperature according to the intake pipe pressure, and to obtain the second refrigerant saturation temperature according to the exhaust pipe pressure; the refrigerant saturation temperature acquisition unit 13 obtains the first refrigerant saturation temperature and the second refrigerant saturation temperature according to the intake pipe pressure, the exhaust pipe pressure and the corresponding refrigerant pressure and saturation curve.

[0082] The superheat calculation unit 14 is used to obtain the intake superheat according to the intake pipe temperature and the first refrigerant saturation temperature, and to obtain the exhaust superheat according to the exhaust pipe temperature and the second refrigerant saturation temperature.

[0083] The leakage level determination module 20 is used to determine the refrigerant leakage level according to the suction superheat and the exhaust superheat; specifically, the leakage level determination module 20 determines the leakage level of the refrigerant (R290) according to the suction superheat value and the exhaust superheat value, wherein the higher the refrigerant leakage level, the more serious the refrigerant leakage.

[0084] The control module 30 is used to control the reduction of the speed of the compressor, and / or the increase of the opening 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 to the refrigerant inlet of the condenser. Specifically, as the refrigerant leakage level increases, the control module 30 controls the speed of the compressor to gradually decrease until it is closed, the opening of the expansion valve to gradually increase until it is fully opened, and the speed of the cooling fan to gradually increase until it rotates at the maximum speed.

[0085] For the specific definition of the control system for the safety of the thermal management system of an electric vehicle, please refer to the definition of the control method for the safety of the thermal management system mentioned above, which will not be repeated here. Each module in the above-mentioned control system for the safety of the thermal management system of an electric vehicle can be implemented in whole or in part by software, hardware, and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0086] See also Figure 1 As shown, the present invention further proposes a vehicle, the vehicle comprising a thermal management system and a controller, the controller is used to control the thermal management system to implement the thermal management system safety control method as described in any one of the above embodiments, specifically implementing the following steps:

[0087] Obtain the suction superheat at the compressor inlet and the exhaust superheat at the compressor outlet;

[0088] determining a refrigerant leakage level according to the suction superheat and the exhaust superheat;

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

[0090] The present invention proposes a control method, system and vehicle for the safety of a thermal management system, which determine the leakage level of R290 refrigerant by monitoring the suction superheat of the compressor suction pipe and the exhaust superheat of the exhaust pipe, so as to adopt a corresponding control scheme to reduce the local refrigerant accumulation concentration; at the same time, if the refrigerant leakage level cannot be controlled within a certain period of time, the spread of the leakage can be controlled by upgrading the leakage level; the present application utilizes the existing sensors of the existing thermal management system and uses a suitable algorithm to determine the refrigerant leakage without increasing the cost, and at the same time controls the spread of the leakage by controlling the actions of different components in the thermal management system, without adding additional fans to implement protective measures, and the cost is relatively low.

[0091] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

[0092] Except for the technical features described in the specification, the remaining technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present invention, the remaining technical features will not be described here in detail.

Claims

1. A method for controlling the safety of a thermal management system, characterized in that: include: Obtain the suction superheat at the compressor inlet and the exhaust superheat at the compressor outlet; determining a refrigerant leakage level according to the suction superheat and the exhaust superheat; The rotation speed of the compressor is reduced according to the leakage level control, and / or the opening of the expansion valve is increased, and / or the rotation speed of the cooling fan is increased, wherein the expansion valve is connected to the refrigerant inlet of the condenser.

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

3. The thermal management system safety control method according to claim 1, characterized in that: The step of controlling to reduce the speed of the compressor according to the leakage level, and / or increasing the opening of the expansion valve, and / or increasing the speed of the cooling fan comprises: Before the refrigerant leakage level rises to the highest leakage level, as the refrigerant leakage level increases, the speed of the compressor is controlled to gradually decrease, and / or the opening of the expansion valve is controlled to gradually increase until it is fully opened, and / or the speed of the cooling fan is controlled to gradually increase until it rotates at the maximum speed, wherein when the refrigerant leakage level rises to the highest, the compressor and the expansion valve are closed.

4. The method for controlling the safety of a thermal management system according to claim 3, characterized in that: The determining of the refrigerant leakage level according to the suction superheat and the exhaust superheat comprises: When the first suction threshold value is less than the suction superheat degree ≤ the second suction threshold value, and the first exhaust threshold value is less than the exhaust superheat degree ≤ the second exhaust threshold value, the refrigerant leakage level is the first leakage level; When the second suction threshold value is less than the suction superheat degree ≤ the third suction threshold value, and the second exhaust threshold value is less than the exhaust superheat degree ≤ the third exhaust threshold value, the refrigerant leakage level is the second leakage level; When the suction superheat degree is greater than the third suction threshold value, and the discharge superheat degree is greater than the third discharge threshold value, the refrigerant leakage level is the third leakage level.

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

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

7. The method for controlling the safety of a thermal management system according to claim 3, characterized in that: After the actions of reducing the speed of the compressor according to the current leakage level control, and / or increasing the opening of the expansion valve, and / or increasing the speed of the cooling fan are completed, the method further includes: 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, and the compressor speed is controlled to be reduced, and / or the opening of the expansion valve is increased, and / or the speed of the cooling fan is increased to complete the corresponding leakage level action.

8. The method for controlling the safety of a thermal management system according to claim 3, characterized in that: After the actions of reducing the speed of the compressor according to the current leakage level control, and / or increasing the opening of the expansion valve, and / or increasing the speed of the cooling fan are completed, the method further includes: Obtaining the suction superheat and the exhaust superheat again after a second preset time interval; If the suction superheat and the exhaust superheat do not decrease, it is determined that the refrigerant leakage level increases, and the control jumps to the next leakage level; According to the level of the next leakage level, the speed of the compressor is controlled to be reduced, and / or the opening of the expansion valve is increased, and / or the speed of the cooling fan is increased to complete the action of the corresponding level.

9. A control system for the safety of an electric vehicle thermal management system, characterized in that: include: A superheat acquisition module is used to obtain the suction superheat at the compressor inlet and the exhaust superheat at the compressor outlet; A leakage level determination module, used for determining the refrigerant leakage level according to the suction superheat and the exhaust superheat; A control module is used to control the reduction of the speed of the compressor and / or increase the opening of the expansion valve and / or increase the speed of the cooling fan according to the leakage level, wherein the expansion valve is connected to the refrigerant inlet of the condenser.

10. A vehicle, characterized in that: The vehicle includes a thermal management system and a controller, wherein the controller is used to control the thermal management system to implement the thermal management system safety control method according to any one of claims 1 to 8.

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