Method and device for determining refrigerant type, fuel cell system and medium

Abstract

The invention provides a method and a device for determining a refrigerant type, a fuel cell system and a medium. The method is applied to a fuel cell control unit in the fuel cell system, the fuel cell system further comprises a fuel cell stack and a thermal management subsystem, and a refrigerant flows in the thermal management subsystem and is used for adjusting the temperature of the fuel cell stack. The method comprises the following steps: acquiring a first pressure value of a refrigerant at an inlet of a fuel cell stack and a second pressure value of the refrigerant at an outlet of the fuel cell stack; and the type of the refrigerant is determined according to the difference value between the first pressure value and the second pressure value. In the application, the fuel cell control unit can automatically identify the type of the refrigerant in the fuel cell system, so that the conditions of low efficiency and high error rate during manual identification are avoided, and the refrigerant identification efficiency and the accuracy of an identification result are remarkably improved. When the identification result is applied to the control scene of the fuel cell system, the control precision of the fuel cell system can be improved.

Description

Technical Field

[0001] The present application relates to the automotive field, and in particular to a method and device for determining a refrigerant type, a fuel cell system, and a medium. Background Art

[0002] Fuel cell vehicles have gradually been widely used in the field of new energy vehicles because of their advantages such as long driving range, high power generation efficiency, pollution-free discharged water, and no need for frequent energy replenishment. The refrigerant in the fuel cell system has a great impact on the performance and life of the fuel cell system. The refrigerant itself is used for heat dissipation, but it also needs to circulate inside the fuel cell stack. The types of refrigerants commonly used at present include deionized water, ethylene glycol coolant, etc., and users often manually replace the refrigerant according to the actual environmental conditions. In some control scenarios for fuel cell systems, the parameters of the refrigerant are needed, and whether the working state of the fuel cell system can be accurately controlled depends on whether the parameters of the refrigerant can be accurately obtained, and whether the parameters of the refrigerant can be accurately obtained depends on whether the type of refrigerant in the fuel cell system at the current moment can be accurately identified. However, there is currently no solution in the relevant technology that can detect the type of refrigerant in the fuel cell system. Summary of the invention

[0003] The present application provides a method, device, fuel cell system and medium for determining the type of refrigerant, which can automatically identify the type of refrigerant in the fuel cell system without manual active identification, avoiding the situation of low efficiency and high error rate during manual identification, and significantly improving the efficiency of refrigerant identification and the accuracy of identification results. When the identification result of the refrigerant type is applied to the control scenario of the fuel cell system, it can also improve the control accuracy of the working state of the fuel cell system.

[0004] In a first aspect, the present application provides a method for determining a refrigerant type, which is applied to a fuel cell control unit in a fuel cell system, wherein the fuel cell system further includes a fuel cell stack and a thermal management subsystem, wherein a refrigerant flows in the thermal management subsystem, and the refrigerant is used to adjust the temperature of the fuel cell stack, and the method includes:

[0005] Acquiring a first pressure value of the refrigerant at an inlet of the fuel cell stack and a second pressure value of the refrigerant at an outlet of the fuel cell stack;

[0006] The type of the refrigerant is determined according to the difference between the first pressure value and the second pressure value.

[0007] Optionally, after determining the type of the refrigerant, the method further includes:

[0008] According to the refrigerant parameters matching the type, based on the model predictive control algorithm, the working state of the fuel cell system is controlled.

[0009] Optionally, determining the type of the refrigerant according to the difference between the first pressure value and the second pressure value includes:

[0010] Determining, among a plurality of pressure difference intervals, whether there is a target pressure difference interval to which the difference value belongs;

[0011] If the target pressure difference interval exists, the type of the refrigerant is determined according to the corresponding relationship between the target pressure difference interval and the preset pressure difference interval and the refrigerant type.

[0012] Optionally, the thermal management subsystem includes a water pump and a temperature control valve, the water pump is used to provide power for the circulation of the refrigerant, the temperature control valve is used to adjust the flow of the refrigerant according to the temperature of the fuel cell stack, and the determining whether there is a target pressure difference interval to which the difference value belongs in the multiple pressure difference intervals includes:

[0013] Obtaining the rotation speed of the water pump and the valve opening of the temperature control valve;

[0014] According to the rotation speed of the water pump and the valve opening, it is determined whether there is a target pressure difference interval to which the difference value belongs in the plurality of pressure difference intervals.

[0015] Optionally, the plurality of pressure difference intervals are pre-determined by the following steps:

[0016] Determining a combination of at least one rotation speed of the water pump and the valve opening according to at least one rotation speed of the water pump and at least one valve opening;

[0017] For each of the combinations, the pressure difference intervals corresponding to the different types of refrigerants are obtained to obtain a plurality of pressure difference intervals;

[0018] The determining, based on the rotation speed of the water pump and the valve opening, whether there is a target pressure difference interval to which the difference value belongs in the plurality of pressure difference intervals comprises:

[0019] It is determined whether there is a target pressure difference interval to which the difference value belongs among the plurality of pressure difference intervals corresponding to the combinations of the rotation speed of the water pump and the valve opening.

[0020] Optionally, after determining whether there is a target pressure difference interval to which the difference value belongs, the method further includes:

[0021] If the target pressure difference interval does not exist, the type of the refrigerant is determined according to the refrigerant information input by the user.

[0022] Optionally, the thermal management subsystem includes a first pressure sensor and a second pressure sensor, the first pressure sensor is arranged at the inlet of the refrigerant relative to the fuel cell stack, and the second pressure sensor is arranged at the outlet of the refrigerant relative to the fuel cell stack; the obtaining of a first pressure value of the refrigerant at the inlet of the fuel cell stack and a second pressure value of the refrigerant at the outlet of the fuel cell stack includes:

[0023] The first pressure value is acquired through the first pressure sensor, and the second pressure value is acquired through the second pressure sensor.

[0024] In a second aspect, the present application provides a device for determining a refrigerant type, which is applied to a fuel cell system, wherein the fuel cell system includes a fuel cell stack and a thermal management subsystem, wherein a refrigerant flows in the thermal management subsystem, and the refrigerant is used to adjust the temperature of the fuel cell stack, and the device includes:

[0025] An acquisition module, used to acquire a first pressure value of the refrigerant at the inlet of the fuel cell stack and a second pressure value of the refrigerant at the outlet of the fuel cell stack;

[0026] The first determination module is used to determine the type of the refrigerant according to the difference between the first pressure value and the second pressure value.

[0027] Optionally, the device further comprises:

[0028] A control module is used to control the working state of the fuel cell system based on a model predictive control algorithm according to refrigerant parameters matching the type.

[0029] Optionally, the first determining module includes:

[0030] A first determination submodule is used to determine whether there is a target pressure difference interval to which the difference value belongs among multiple pressure difference intervals;

[0031] The second determination submodule is configured to determine the type of the refrigerant according to a correspondence between the target pressure difference interval and a preset pressure difference interval and the refrigerant type if the target pressure difference interval exists.

[0032] Optionally, the thermal management subsystem includes a water pump and a temperature control valve, the water pump is used to provide power for the circulation of the refrigerant, the temperature control valve is used to adjust the flow of the refrigerant according to the temperature of the fuel cell stack, and in the multiple pressure difference intervals, the first determination submodule includes:

[0033] A first acquisition submodule is used to acquire the rotation speed of the water pump and the valve opening of the temperature control valve;

[0034] The third determination submodule is used to determine whether there is a target pressure difference interval to which the difference belongs in the plurality of pressure difference intervals according to the rotation speed of the water pump and the valve opening.

[0035] Optionally, the plurality of pressure difference intervals are pre-determined by the following steps:

[0036] Determining a combination of at least one rotation speed of the water pump and the valve opening according to at least one rotation speed of the water pump and at least one valve opening;

[0037] For each of the combinations, the pressure difference intervals corresponding to the different types of refrigerants are obtained to obtain a plurality of pressure difference intervals;

[0038] The third determining submodule comprises:

[0039] The fourth determination submodule is used to determine whether there is a target pressure difference interval to which the difference belongs among the plurality of pressure difference intervals corresponding to the combination of the rotation speed of the water pump and the valve opening.

[0040] Optionally, the device further comprises:

[0041] The second determination module is configured to determine the type of the refrigerant according to the refrigerant information input by the user if the target pressure difference interval does not exist.

[0042] Optionally, the thermal management subsystem includes a first pressure sensor and a second pressure sensor, the first pressure sensor is arranged at the inlet of the refrigerant relative to the fuel cell stack, and the second pressure sensor is arranged at the outlet of the refrigerant relative to the fuel cell stack; the acquisition module includes:

[0043] The second acquisition submodule is configured to acquire the first pressure value through the first pressure sensor, and acquire the second pressure value through the second pressure sensor.

[0044] In a third aspect, the present application provides a fuel cell system, including a fuel cell stack, a thermal management subsystem and a fuel cell control unit, wherein a refrigerant flows in the thermal management subsystem, and the refrigerant is used to regulate the temperature of the fuel cell stack. The fuel cell control unit is used to execute a method for determining the refrigerant type as described in the first aspect of the present application.

[0045] In a fourth aspect, the present application provides a non-temporary computer-readable storage medium. When the instructions in the storage medium are executed by a fuel cell control unit in a fuel cell system, the fuel cell control unit is enabled to execute a method for determining a refrigerant type as described in the first aspect of the present application.

[0046] The method for determining the type of refrigerant in a fuel cell system in the present application is adopted to first obtain a first pressure value of the refrigerant at the inlet of the fuel cell stack and a second pressure value at the outlet of the fuel cell stack; then the type of the refrigerant is determined according to the difference between the first pressure value and the second pressure value. Through the method of the present application, the fuel cell control unit can automatically identify the type of refrigerant in the fuel cell system without manual active identification, which can avoid the situation of low efficiency and high error rate during manual identification, and significantly improve the efficiency of refrigerant identification and the accuracy of identification results. In addition, the identification results of the refrigerant type can be applied to the control scenarios for the fuel cell system. Due to the high accuracy of the refrigerant identification results, the control accuracy of the working state of the fuel cell system can be improved to ensure the stable operation of the fuel cell system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 is a structural schematic diagram of a fuel cell system shown in one embodiment of the present application;

[0049] Figure 2 is a flow chart of a method for determining the type of refrigerant in a fuel cell system according to an embodiment of the present application;

[0050] Figure 3 is a flow chart of a method for determining the type of refrigerant in a fuel cell system according to an embodiment of the present application;

[0051] Figure 4 This is a structural block diagram of a device for determining the type of refrigerant in a fuel cell system shown in one embodiment of the present application. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0053] The present application provides a method for determining the type of refrigerant in a fuel cell system, which is specifically applied to a fuel cell control unit (FCU) in the fuel cell system. Before describing the method in detail, the fuel cell system of the present application is first introduced below. Figure 1 It is a structural schematic diagram of a fuel cell system shown in one embodiment of the present application.

[0054] Reference Figure 1 The fuel cell system of the present application includes a fuel cell stack 1, a thermal management subsystem and a fuel cell control unit 7. A refrigerant flows in the thermal management subsystem, and the refrigerant is used to adjust the temperature of the fuel cell stack.

[0055] Among them, the thermal management subsystem includes an integrated temperature and pressure sensor 2 for entering the stack, a water pump 3, a heat dissipation assembly 4, a deionizer 5, a temperature control valve 6, an intercooler 8, a water tank 9 and an integrated temperature and pressure sensor 10 for exiting the stack. The integrated temperature and pressure sensor has the function of detecting both temperature and pressure. The heat dissipation assembly 4 is mainly responsible for the effective dissipation of the heat generated by the fuel cell stack 1 during operation to maintain the fuel cell stack 1 operating within a suitable operating temperature range. The deionizer 5 is used to remove conductive ions in the refrigerant to maintain the conductivity of the refrigerant at a stable and low level. The function of the intercooler 8 is to cool the air entering the fuel cell stack 1 to ensure that the fuel cell stack 1 operates at a suitable temperature.

[0056] Figure 2 FIG. 1 is a flow chart of a method for determining the type of refrigerant in a fuel cell system according to an embodiment of the present application. Figure 2 The method for determining the type of refrigerant in a fuel cell system of the present application may include the following steps:

[0057] S11: obtaining a first pressure value of the refrigerant at the inlet of the fuel cell stack 1 and a second pressure value of the refrigerant at the outlet of the fuel cell stack 1 .

[0058] In this embodiment, the thermal management subsystem includes a first pressure sensor and a second pressure sensor. Figure 1 The inlet temperature and pressure integrated sensor 2 is arranged at the inlet of the refrigerant relative to the fuel cell stack 1. The second pressure sensor is Figure 1 The stack outlet temperature and pressure integrated sensor 10 is arranged at the outlet of the refrigerant relative to the fuel cell stack 1.

[0059] Accordingly, S11 specifically includes:

[0060] The first pressure value is obtained through the inlet temperature-pressure integrated sensor 2 , and the second pressure value is obtained through the outlet temperature-pressure integrated sensor 10 .

[0061] S12: Determine the type of refrigerant according to the difference between the first pressure value and the second pressure value.

[0062] In S12, the difference between the first pressure value and the second pressure value is first determined, and then the type of the refrigerant is determined according to the difference.

[0063] The principle of determining the type of refrigerant based on the pressure difference between the refrigerant entering and exiting the fuel cell stack 1 will be described in detail below:

[0064] The refrigerant in the fuel cell system needs a special pressure difference to flow in the fuel cell stack 1 to overcome the friction of the internal pipes and joints of the fuel cell stack 1. The pressure difference depends on the diameter, length, shape, surface finish and Reynolds number of the internal pipes of the fuel cell stack 1. The Reynolds number is the ratio of inertia to the friction coefficient of the flowing medium, which is a dimensionless coefficient and is defined as:

[0065]

[0066] In the above formula, R e represents the Reynolds number, D represents the diameter of the pipe inside the fuel cell stack 1 (unit: m), w represents the average flow velocity (unit: m / s), and ρ represents the density of the flow medium (unit: kg / m 3 ), η represents the dynamic viscosity of the flowing medium (unit: Pa.s).

[0067] When the structure and components of the fuel cell system are determined, the diameter D, length, shape, and surface finish of the internal pipeline of the fuel cell stack 1 remain unchanged, and the pressure difference of the refrigerant entering and leaving the fuel cell stack 1 is determined by the Reynolds number R e When the speed of the water pump 3 and the opening of the temperature control valve 6 are fixed, the average flow velocity w is also fixed, so the Reynolds number R e It depends on the density ρ of the flowing medium and the dynamic viscosity η of the flowing medium, and the density ρ of the flowing medium and the dynamic viscosity η of the flowing medium are both inherent characteristics of the medium. Therefore, the type of the medium can be judged by the pressure difference of the medium entering and exiting the fuel cell stack 1 relative to the fuel cell stack. The above-mentioned medium is also the refrigerant in this application.

[0068] Using the method of determining the type of refrigerant in the fuel cell system in the present application, first obtain a first pressure value of the refrigerant at the inlet of the fuel cell stack 1 and a second pressure value at the outlet of the fuel cell stack 1; then determine the type of refrigerant based on the difference between the first pressure value and the second pressure value. Through the method of the present application, the fuel cell control unit 7 can automatically identify the type of refrigerant in the fuel cell system, significantly improving the efficiency of refrigerant identification and the accuracy of the identification results. In addition, the identification results of the refrigerant type can be applied to control scenarios for fuel cell systems. Due to the high accuracy of the refrigerant identification results, the control accuracy of the working state of the fuel cell system can be significantly improved.

[0069] In combination with the above embodiments, in one implementation manner, after determining the type of the refrigerant, the method further includes:

[0070] S13: According to the refrigerant parameters matching the type of the refrigerant, based on the model predictive control algorithm, the working state of the fuel cell system is controlled.

[0071] Specifically, S13 may include:

[0072] Importing refrigerant parameters matching the type into the simulation model corresponding to the fuel cell system;

[0073] According to the simulation model, the working state of the fuel cell system is controlled based on the model predictive control algorithm.

[0074] In this embodiment, the identification result of the refrigerant type can be applied to a model predictive control (MPC) algorithm.

[0075] Generally, the control of fuel cell systems can adopt PID (Proportional-Integral-Derivative Control) feedforward control method, model predictive control method, etc. PID controller combines the three basic control functions of proportion, integration and differentiation to deal with the static error, dynamic response and steady-state accuracy problems in the system. Model predictive control performs prediction and optimization control based on the dynamic model of the controlled object. It determines the future control input sequence by solving the finite time domain optimization problem online to optimize a performance indicator. The main steps of the algorithm include establishing a system model (a mathematical model that describes the dynamic behavior of the system, which can be a state space equation, transfer function, neural network model, etc.), model linearization and discretization, prediction model derivation, design objective function, set constraints, optimization solution, application of control input, feedback correction.

[0076] In the present application, the core of applying the model predictive control method to the field of fuel cell system control is to establish an accurate simulation fuel cell system model. In the modeling process based on the mechanism formula, it is necessary to simulate and calculate the heat exchange and pressure drop in the thermal management subsystem. If the type of refrigerant used in the thermal management subsystem is unclear (different types of refrigerants have different thermodynamic, fluid mechanics and other parameter values), then it is impossible to import accurate refrigerant parameter values ​​into the fuel cell system model, which will cause the fuel cell system model to be unable to output accurate simulation calculation results, and further cause the fuel cell control unit 7 to be unable to accurately control the working state of the fuel cell system based on the model predictive control algorithm.

[0077] Based on the above problems, the control of the fuel cell system in the related art mainly adopts the PID feedforward control method. However, the method of this application can quickly and accurately identify the type of refrigerant, and then import accurate refrigerant parameter values ​​into the fuel cell system model, thus overcoming the above problems and finally achieving effective control of the working state of the fuel cell system through the model predictive control algorithm.

[0078] In this embodiment, the refrigerant has multiple types, including but not limited to: deionized water (with characteristics such as low price and no antifreeze at low temperature), ethylene glycol coolant (with characteristics such as good antifreeze performance and low conductivity). When the user actually uses the vehicle, he often manually replaces the refrigerant of the fuel cell system according to demand (for example, when the ambient temperature is higher than 0°C, in order to reduce costs, deionized water is often used as a refrigerant, and when there is a need for antifreeze, ethylene glycol coolant is often used as a refrigerant), resulting in a change in the type of refrigerant. The fuel cell control unit 7 cannot accurately control the working state of the fuel cell system if the user does not actively inform the type of refrigerant. If the user is required to actively inform the fuel cell control unit 7 of the refrigerant information every time, it will undoubtedly bring a huge burden to the user and reduce the user's driving experience. Therefore, using the method for determining the type of refrigerant in the fuel cell system provided by the present application, the fuel cell control unit 7 can automatically identify the type of refrigerant in the fuel cell system, which can not only ensure the user's driving experience, but also contribute to the smooth implementation of the model predictive control algorithm.

[0079] In combination with the above embodiments, in one implementation, in S12, determining the type of refrigerant according to the difference between the first pressure value and the second pressure value may include:

[0080] S121: Determine whether there is a target pressure difference interval to which the difference value belongs in a plurality of pressure difference intervals;

[0081] S122: If there is a target pressure difference range, determine the type of refrigerant according to the corresponding relationship between the target pressure difference range and the preset pressure difference range and the refrigerant type.

[0082] In this embodiment, the multiple pressure difference intervals are pressure difference intervals determined in advance through multiple tests, and each pressure difference interval uniquely corresponds to a refrigerant type. Therefore, after calculating the pressure difference between the first pressure value and the second pressure value, the target pressure difference interval in which the difference is located is first determined, and then, based on the correspondence between the pressure difference interval and the refrigerant type, the refrigerant type corresponding to the target pressure difference interval is directly used as the type of refrigerant flowing in the fuel cell system at the current moment.

[0083] It is particularly noted here that the various pressure difference intervals in the present application do not overlap with each other, that is, there will not be a situation where the determined pressure differences are simultaneously in different pressure difference intervals.

[0084] For example, the predetermined multiple pressure difference intervals include △PAmin~△PAmax, △PBmin~△PBmax, △PCmin~△PCmax, wherein △PAmin~△PAmax is the pressure difference interval corresponding to the refrigerant of type A, △PBmin~△PBmax is the pressure difference interval corresponding to the refrigerant of type B, and △PCmin~△PCmax is the pressure difference interval corresponding to the refrigerant of type C. If the calculated pressure difference is △P, it is determined in which pressure difference interval △P is located, if △PAmin≤△P≤△PAmax is satisfied, the type of the refrigerant is determined to be type A, if △PBmin≤△P≤PBmax is satisfied, the type of the refrigerant is determined to be type B, and if △PCmin≤△P≤△PCmax is satisfied, the type of the refrigerant is determined to be type C.

[0085] Through this embodiment, the type of refrigerant can be quickly determined according to the pressure difference range in which the difference between the first pressure value and the second pressure value lies.

[0086] In combination with the above embodiments, in one implementation, the thermal management subsystem includes a water pump 3 and a temperature control valve 6, the water pump 3 is used to provide power for the circulation of the refrigerant, and the temperature control valve 6 is used to adjust the flow of the refrigerant according to the temperature of the fuel cell stack 1. In multiple pressure difference intervals, determining whether there is a target pressure difference interval to which the difference belongs may include:

[0087] Obtain the rotation speed of the water pump 3 and the valve opening of the temperature control valve 6;

[0088] According to the rotation speed and valve opening of the water pump 3, it is determined whether there is a target pressure difference interval to which the difference value belongs in a plurality of pressure difference intervals.

[0089] In this embodiment, the plurality of pressure difference intervals can be determined in advance according to the rotation speed of the water pump 3 and the valve opening of the temperature control valve 6 by the following steps:

[0090] Determine a combination of at least one rotation speed of the water pump 3 and the valve opening according to at least one rotation speed of the water pump 3 and at least one valve opening;

[0091] For each combination, the pressure difference intervals corresponding to the different types of refrigerants are obtained to obtain multiple pressure difference intervals.

[0092] In this embodiment, there may be multiple rotation speeds of the water pump 3, and there may be multiple valve openings of the temperature control valve 6. Therefore, there will be multiple different combinations of different rotation speeds of the water pump 3 and different valve openings. For each combination, for different types of refrigerants, the difference between the first pressure value and the second pressure value is collected multiple times to obtain the fluctuation range of the difference, and the fluctuation range of the pressure difference corresponding to each type of refrigerant is used as the corresponding pressure difference range. For example, there are n rotation speeds of the water pump 3, and m valve openings of the temperature control valve 6, then there are m*n combinations. Assuming that there are 2 types of refrigerants, there are pressure difference ranges corresponding to the 2 types of refrigerants in each combination, as shown in Table 1 below.

[0093]

[0094]

[0095] Table 1

[0096] In conjunction with Table 1, in one embodiment, the types of refrigerants include deionized water and ethylene glycol coolant, deionized water is a type 1 refrigerant, and ethylene glycol coolant is a type 2 refrigerant. In the process of collecting the data in Table 1, the refrigerant in the cooling pipeline of the thermal management subsystem is first replaced with deionized water, and then the fuel cell system is started. After the speed of the water pump 3 reaches speed 1 and the valve opening of the temperature control valve 6 reaches valve opening 1, the fuel cell control unit 7 reads the first pressure value detected by the inlet temperature and pressure integrated sensor 2 and the second pressure value detected by the outlet temperature and pressure integrated sensor 10 at this moment, and calculates the pressure difference value. Repeat the measurement multiple times to obtain the fluctuation range of the pressure difference value, which can be used as the pressure difference interval corresponding to the combination of deionized water speed 1 and valve opening 1. Next, the refrigerant in the cooling pipeline of the thermal management subsystem is replaced with ethylene glycol coolant, and then the fuel cell system is started. After the speed of the water pump 3 reaches speed 1 and the valve opening of the temperature control valve 6 reaches valve opening 1, the fuel cell control unit 7 reads the first pressure value detected by the inlet temperature and pressure integrated sensor 2 and the second pressure value detected by the outlet temperature and pressure integrated sensor 10 at this moment, and calculates the pressure difference value. Repeat the measurement multiple times to obtain the fluctuation range of the pressure difference value, which can be used as the pressure difference range corresponding to the combination of ethylene glycol coolant speed 1 and valve opening 1. According to the same principle as above, the pressure difference range corresponding to each type of refrigerant under multiple different combinations of speeds and valve openings can be obtained.

[0097] Accordingly, according to the rotation speed and valve opening of the water pump 3, determining whether there is a target pressure difference interval to which the difference value belongs in a plurality of pressure difference intervals may include:

[0098] It is determined whether there is a target pressure difference interval to which the difference value belongs among the plurality of pressure difference intervals corresponding to the combinations of the rotation speed and the valve opening of the water pump 3 .

[0099] In this embodiment, after obtaining the inlet and outlet stack pressure difference of the refrigerant at the current moment, multiple pressure difference intervals corresponding to the combination of the speed of the water pump 3 and the valve opening at the current moment can be screened out from the multiple pressure difference intervals shown in Table 1 according to the combination of the speed of the water pump 3 and the valve opening at the current moment, and then the target pressure difference interval where the inlet and outlet stack pressure difference is located is further determined in this screened part of the pressure difference interval. For example, if the speed of the water pump 3 at the current moment is speed 1 and the valve opening is valve opening 1, then the target pressure interval is determined in the pressure difference interval 11 (refrigerant of type 1) and the pressure difference interval 11' (refrigerant of type 2). For another example, if the speed of the water pump 3 at the current moment is speed 2 and the valve opening is valve opening 1, then the target pressure interval is determined in the pressure difference interval 21 (refrigerant of type 1) and the pressure difference interval 21' (refrigerant of type 2).

[0100] In this embodiment, a plurality of pressure difference intervals are determined in advance according to the rotation speed of the water pump 3 and the valve opening of the temperature control valve 6. Thus, after obtaining the inlet and outlet stack pressure difference of the refrigerant, the target pressure difference interval to which the inlet and outlet stack pressure difference of the refrigerant belongs can be quickly and accurately determined according to the combination of the rotation speed of the water pump 3 and the valve opening of the temperature control valve 6.

[0101] In combination with the above embodiments, in one implementation, after determining whether there is a target pressure difference interval to which the difference value belongs, the method of the present application may further include:

[0102] If the target pressure difference range does not exist, the type of refrigerant is determined according to the refrigerant information input by the user.

[0103] In this embodiment, if the target pressure difference interval of the refrigerant inlet and outlet pressure difference cannot be determined, the user actively inputs the type of refrigerant. Generally, if the number and types of multiple pressure intervals obtained by pre-testing in this embodiment are rich enough, there will be almost no situation where the target pressure difference interval cannot be determined.

[0104] Figure 3 This is a flow chart of a method for determining the type of refrigerant in a fuel cell system according to an embodiment of the present application. Figure 3 The method for determining the type of refrigerant in a fuel cell system of the present application is described in detail with a complete embodiment. In this embodiment, the types of refrigerants are mainly divided into type A and type B.

[0105] During the start-up process of the fuel cell system, when the speed of the water pump 3 reaches the start-up speed X and the valve opening of the temperature control valve 6 reaches the valve opening Y, the fuel cell control unit 7 receives the pressure values ​​of the inlet temperature and pressure integrated sensor 2 and the outlet temperature and pressure integrated sensor 10 at that moment, and then calculates the inlet and outlet pressure difference △P of the refrigerant relative to the fuel cell stack 1 at that moment. Next, the fuel cell control unit 7 searches for the target pressure difference interval where △P is located in the multiple preset pressure difference intervals corresponding to the combination of the speed X and the valve opening Y. If △PAmin≤△P≤△PAmax (i.e., the pressure difference interval corresponding to the refrigerant of type A), the type of the refrigerant is determined to be type A. If △PBmin≤△P≤PBmax (i.e., the pressure difference interval corresponding to the refrigerant of type B) is satisfied, the type of the refrigerant is determined to be type B. If there is no target pressure difference interval, it is prompted to manually confirm the type of the refrigerant.

[0106] In summary, the technical solution of this application has at least the following technical effects:

[0107] First, the present application can determine the type of refrigerant only through the inlet temperature and pressure integrated sensor 2 and the outlet temperature and pressure integrated sensor 10 in the thermal management subsystem, without the need to install other types of sensors to detect the type of refrigerant, which can effectively reduce the cost of the fuel cell system.

[0108] Second, the present application can automatically identify the type of refrigerant through the program, and then import accurate refrigerant parameter values ​​into the fuel cell system model, thereby achieving effective control of the working state of the fuel cell system through the model predictive control algorithm. Due to the high accuracy of the refrigerant identification results, the control accuracy of the working state of the fuel cell system can be significantly improved.

[0109] It should be noted that, for the method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present application are not limited by the described order of actions, because according to the embodiments of the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present application.

[0110] Based on the same inventive concept, an embodiment of the present application provides a device 400 for determining the type of refrigerant, which is applied to a fuel cell system. The fuel cell system includes a fuel cell stack and a thermal management subsystem, wherein a refrigerant flows in the thermal management subsystem, and the refrigerant is used to adjust the temperature of the fuel cell stack. Figure 4 FIG. 1 is a structural block diagram of a device for determining the type of refrigerant according to an embodiment of the present application. Figure 4 As shown, the device 400 includes:

[0111] An acquisition module 401 is used to acquire a first pressure value of the refrigerant at the inlet of the fuel cell stack and a second pressure value of the refrigerant at the outlet of the fuel cell stack;

[0112] The first determination module 402 is configured to determine the type of the refrigerant according to a difference between the first pressure value and the second pressure value.

[0113] Optionally, the device 400 further includes:

[0114] A control module is used to control the working state of the fuel cell system based on a model predictive control algorithm according to refrigerant parameters matching the type.

[0115] Optionally, the first determining module 402 includes:

[0116] A first determination submodule is used to determine whether there is a target pressure difference interval to which the difference value belongs among multiple pressure difference intervals;

[0117] The second determination submodule is configured to determine the type of the refrigerant according to a correspondence between the target pressure difference interval and a preset pressure difference interval and the refrigerant type if the target pressure difference interval exists.

[0118] Optionally, the thermal management subsystem includes a water pump and a temperature control valve, the water pump is used to provide power for the circulation of the refrigerant, the temperature control valve is used to adjust the flow of the refrigerant according to the temperature of the fuel cell stack, and in the multiple pressure difference intervals, the first determination submodule includes:

[0119] A first acquisition submodule is used to acquire the rotation speed of the water pump and the valve opening of the temperature control valve;

[0120] The third determination submodule is used to determine whether there is a target pressure difference interval to which the difference belongs in the plurality of pressure difference intervals according to the rotation speed of the water pump and the valve opening.

[0121] Optionally, the plurality of pressure difference intervals are pre-determined by the following steps:

[0122] Determining a combination of at least one rotation speed of the water pump and the valve opening according to at least one rotation speed of the water pump and at least one valve opening;

[0123] For each of the combinations, the pressure difference intervals corresponding to the different types of refrigerants are obtained to obtain a plurality of pressure difference intervals;

[0124] The third determining submodule comprises:

[0125] The fourth determination submodule is used to determine whether there is a target pressure difference interval to which the difference belongs among the plurality of pressure difference intervals corresponding to the combination of the rotation speed of the water pump and the valve opening.

[0126] Optionally, the device 400 further includes:

[0127] The second determination module is configured to determine the type of the refrigerant according to the refrigerant information input by the user if the target pressure difference interval does not exist.

[0128] Optionally, the thermal management subsystem includes a first pressure sensor and a second pressure sensor, the first pressure sensor is arranged at the inlet of the refrigerant relative to the fuel cell stack, and the second pressure sensor is arranged at the outlet of the refrigerant relative to the fuel cell stack; the acquisition module includes:

[0129] The second acquisition submodule is used to acquire the first pressure value through the first pressure sensor and acquire the second pressure value through the second pressure sensor. As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0130] An embodiment of the present application also provides a fuel cell system, including a fuel cell stack, a thermal management subsystem and a fuel cell control unit, wherein a refrigerant flows in the thermal management subsystem, and the refrigerant is used to regulate the temperature of the fuel cell stack. The fuel cell control unit is used to execute a method for determining the refrigerant type described in an embodiment of the present application.

[0131] In the fuel cell system of the present application, the fuel cell control unit can automatically identify the type of refrigerant in the fuel cell system without manual active identification, avoiding the low efficiency and high error rate of manual identification, and significantly improving the efficiency of refrigerant identification and the accuracy of identification results. In addition, the identification results of the refrigerant type can be applied to the control scenarios for the fuel cell system. Due to the high accuracy of the refrigerant identification results, the control accuracy of the working state of the fuel cell system can be improved to ensure the stable operation of the fuel cell system.

[0132] An embodiment of the present application also provides a non-temporary computer-readable storage medium. When the instructions in the storage medium are executed by a fuel cell control unit in a fuel cell system, the fuel cell control unit is enabled to execute a method for determining a refrigerant type as described in an embodiment of the present application.

[0133] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0134] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0135] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0136] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0137] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0138] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for determining the type of refrigerant, characterized in that: A fuel cell control unit applied to a fuel cell system, the fuel cell system further comprising a fuel cell stack and a thermal management subsystem, a refrigerant flowing in the thermal management subsystem, the refrigerant being used to regulate the temperature of the fuel cell stack, the method comprising: Acquiring a first pressure value of the refrigerant at an inlet of the fuel cell stack and a second pressure value of the refrigerant at an outlet of the fuel cell stack; The type of the refrigerant is determined according to the difference between the first pressure value and the second pressure value.

2. The method according to claim 1, characterized in that After determining the type of the refrigerant, the method further includes: According to the refrigerant parameters matching the type, based on the model predictive control algorithm, the working state of the fuel cell system is controlled.

3. The method according to claim 1, characterized in that The determining the type of the refrigerant according to the difference between the first pressure value and the second pressure value includes: Determining, among a plurality of pressure difference intervals, whether there is a target pressure difference interval to which the difference value belongs; If the target pressure difference interval exists, the type of the refrigerant is determined according to the corresponding relationship between the target pressure difference interval and the preset pressure difference interval and the refrigerant type.

4. The method according to claim 3, characterized in that The thermal management subsystem includes a water pump and a temperature control valve, the water pump is used to provide power for the circulation of the refrigerant, the temperature control valve is used to adjust the flow of the refrigerant according to the temperature of the fuel cell stack, and the determination of whether there is a target pressure difference interval to which the difference value belongs in multiple pressure difference intervals includes: Obtaining the rotation speed of the water pump and the valve opening of the temperature control valve; According to the rotation speed of the water pump and the valve opening, it is determined whether there is a target pressure difference interval to which the difference value belongs in the plurality of pressure difference intervals.

5. The method according to claim 4, characterized in that The plurality of pressure difference intervals are determined in advance by the following steps: Determining a combination of at least one rotation speed of the water pump and the valve opening according to at least one rotation speed of the water pump and at least one valve opening; For each of the combinations, the pressure difference intervals corresponding to the different types of refrigerants are obtained to obtain a plurality of pressure difference intervals; The determining, according to the rotation speed of the water pump and the valve opening, whether there is a target pressure difference interval to which the difference value belongs in the plurality of pressure difference intervals comprises: It is determined whether there is a target pressure difference interval to which the difference value belongs among the plurality of pressure difference intervals corresponding to the combinations of the rotation speed of the water pump and the valve opening.

6. The method according to claim 3, characterized in that After determining whether there is a target pressure difference interval to which the difference value belongs, the method further includes: If the target pressure difference interval does not exist, the type of the refrigerant is determined according to the refrigerant information input by the user.

7. The method according to claim 1, characterized in that The thermal management subsystem includes a first pressure sensor and a second pressure sensor, wherein the first pressure sensor is disposed at an inlet of the refrigerant relative to the fuel cell stack, and the second pressure sensor is disposed at an outlet of the refrigerant relative to the fuel cell stack; the step of obtaining a first pressure value of the refrigerant at the inlet of the fuel cell stack and a second pressure value of the refrigerant at the outlet of the fuel cell stack includes: The first pressure value is acquired through the first pressure sensor, and the second pressure value is acquired through the second pressure sensor.

8. A device for determining the type of refrigerant, characterized in that: Applied to a fuel cell system, the fuel cell system includes a fuel cell stack and a thermal management subsystem, a refrigerant flows in the thermal management subsystem, the refrigerant is used to adjust the temperature of the fuel cell stack, and the device includes: An acquisition module, used to acquire a first pressure value of the refrigerant at the inlet of the fuel cell stack and a second pressure value of the refrigerant at the outlet of the fuel cell stack; The first determination module is used to determine the type of the refrigerant according to the difference between the first pressure value and the second pressure value.

9. A fuel cell system, characterized in that: It includes a fuel cell stack, a thermal management subsystem and a fuel cell control unit. A refrigerant flows in the thermal management subsystem, and the refrigerant is used to regulate the temperature of the fuel cell stack. The fuel cell control unit is used to execute a method for determining the refrigerant type as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, when the instructions in the storage medium are executed by a fuel cell control unit in a fuel cell system, the fuel cell control unit is enabled to execute a method for determining a refrigerant type as described in any one of claims 1 to 7.

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