Integrated fuel cell vehicle thermal management system and control method

Abstract

The present invention discloses an integrated fuel cell vehicle thermal management system and control method, relating to the field of thermal management of new energy hydrogen fuel cell vehicles. The system includes a fuel cell cooling circuit and a fuel cell heating circuit. The fuel cell cooling circuit includes a main cooling water circuit for connecting the fuel cell stack in series, and a cooling water branch connected in parallel to the main cooling water circuit via an electronically controlled three-way valve. The main cooling water circuit is provided with a first stack radiator and a water pump, and the cooling water branch is provided with a second stack radiator. The fuel cell heating circuit is connected to the fuel cell cooling circuits at both ends of the fuel cell stack, and one end of the fuel cell heating circuit is connected to a thermostat provided on the fuel cell cooling circuit. The fuel cell heating circuit is provided with a PTC water heater. The present invention can simplify the control strategy and improve the system control accuracy.

Description

Technical Field

[0001] The present invention relates to the field of thermal management of new energy hydrogen fuel cell vehicles, and in particular to an integrated fuel cell vehicle thermal management system and control method. Background Art

[0002] Hydrogen fuel cells have the characteristics of high power density, no pollution, and low noise, and are an ideal power source for electric vehicles. The optimal operating temperature range of hydrogen fuel cell stacks is generally between 60 and 80°C. If the temperature is too low, the activity of the catalyst inside the fuel cell will be reduced, ohmic polarization will be severe, and the battery impedance will increase, thereby reducing battery performance; if the temperature is too high, it will aggravate the evaporation of liquid water inside the battery and cause the proton exchange membrane to dehydrate and dry out, hindering the conduction of hydrogen ions and reducing the efficiency of the battery. Long-term high temperature will also damage the battery life. Therefore, the stack has high requirements for cooling water temperature, and the inlet water temperature generally requires T f (Flow temperature) ±2℃, the temperature difference between inlet and outlet is less than 10℃.

[0003] Since fuel cells have high requirements for the cooling system and require a small inlet water temperature range, the industry currently uses an independent fuel cell cooling system to reduce control difficulty and achieve control goals.

[0004] The independent fuel cell cooling system is unaffected by other systems and is relatively simple to control. However, due to the high temperature difference between the inlet and outlet of the fuel cell stack and the large space required for the radiator, as the power of the fuel cell stack increases, the vehicle lacks sufficient space for the radiator, resulting in an inability to meet the stack's heat dissipation requirements. Furthermore, fuel cell vehicles must also have a thermal management system for the drive motor, high-voltage accessories, and power batteries to meet the temperature control requirements of various assembly components and the cab. The multiple and dispersed thermal management systems make vehicle layout difficult and installation cumbersome. Summary of the Invention

[0005] In view of the defects existing in the prior art, the purpose of the present invention is to provide an integrated fuel cell vehicle thermal management system and control method, which can simplify the control strategy and improve the system control accuracy.

[0006] To achieve the above objectives, the present invention provides an integrated fuel cell vehicle thermal management system, comprising:

[0007] A fuel cell cooling circuit, comprising a main cooling water circuit for connecting the fuel cell stacks in series, and a branch cooling water circuit connected in parallel to the main cooling water circuit via an electronically controlled three-way valve, the main cooling water circuit being provided with a first fuel cell stack radiator and a water pump, and the branch cooling water circuit being provided with a second fuel cell stack radiator;

[0008] A fuel cell heating circuit, wherein the fuel cell heating circuit is connected to the fuel cell cooling circuit at both ends of the fuel cell stack, and one end of the fuel cell heating circuit is connected to a thermostat provided on the fuel cell cooling circuit, and the fuel cell heating circuit is provided with a PTC water heater;

[0009] Among them, the first stack radiator and the second stack radiator are both equipped with electronic fans, and the first stack radiator is arranged at the front of the vehicle. The first stack radiator is also equipped with an air-conditioning condenser, and the second stack radiator is also equipped with a motor and high-voltage accessory radiator, as well as a water-cooled unit condenser.

[0010] On the basis of the above technical solutions,

[0011] Temperature sensors are provided at both ends of the first stack radiator;

[0012] Temperature sensors are provided at both ends of the second stack radiator;

[0013] Temperature sensors are provided at both ends of the fuel cell stack.

[0014] On the basis of the above technical solutions,

[0015] The fuel cell cooling circuit is also provided with a pressure sensor, a filter and a deionizer, and the fuel cell cooling circuit is also connected to an expansion water tank;

[0016] The water-cooling unit condenser is the condenser of the battery water-cooling unit of the power battery, and the motor and high-voltage accessory radiator is connected to the motor and high-voltage accessories.

[0017] The present invention provides an integrated fuel cell vehicle thermal management control method for controlling the integrated fuel cell vehicle thermal management system described above, specifically including fuel cell stack startup heating control logic and fuel cell stack cooling control logic;

[0018] The fuel cell stack startup heating control logic is specifically as follows:

[0019] For startup at low ambient temperatures, the water pump is turned on and initially heated by a PTC water heater. The vehicle's waste heat is then used to heat the coolant in the second stack radiator.

[0020] For startup at room temperature, the water pump is turned on to use the waste heat of the vehicle to heat the coolant in the second stack radiator;

[0021] For startup at high ambient temperature, only the water pump is turned on;

[0022] The fuel cell stack cooling control logic is specifically as follows:

[0023] Initially, only the electronic fan at the first stack radiator works, and as the water inlet temperature of the fuel cell stack rises, the electronic fan at the second stack radiator works, and the opening of the electronically controlled three-way valve and the speed of the electronic fans at the first and second stack radiators are dynamically adjusted.

[0024] Based on the above technical solution, for startup at low ambient temperature, the water pump is turned on, and the PTC water heater is initially used for heating. Then, the waste heat of the vehicle is used to heat the coolant in the second stack radiator. The specific steps include:

[0025] The water pump and PTC water heater are turned on, and the PTC water heater is controlled by the thermostat to heat the fuel cell stack;

[0026] Then when the water inlet temperature of the fuel cell stack is higher than the temperature T fw0 When the PTC water heater is turned off, the thermostat is adjusted and the fuel cell cooling circuit enters circulation;

[0027] Then when the outlet temperature of the motor and high-voltage accessories radiator is T ra When the temperature is higher than the set temperature, the electronically controlled three-way valve opens, and the electronic fan at the second stack radiator starts to work, using the hot air passing through the water-cooled unit condenser, motor, and high-voltage accessory radiator to heat the coolant in the second stack radiator;

[0028] After that, when the water inlet temperature of the second stack radiator is higher than T ra At -1℃, the electric three-way valve is closed.

[0029] On the basis of the above technical solution, for startup under normal temperature, the water pump is turned on and the coolant in the second stack radiator is heated by utilizing the waste heat of the vehicle. The specific steps include:

[0030] The water pump is turned on, and the thermostat controls only the fuel cell cooling circuit to be connected to the fuel cell stack, and the electronic fan at the first stack radiator is turned off;

[0031] Then when the outlet temperature of the motor and high-voltage accessories radiator is T ra When the temperature is higher than the set temperature, the electronically controlled three-way valve opens, and the electronic fan at the second stack radiator starts to work, using the hot air passing through the water-cooled unit condenser, motor, and high-voltage accessory radiator to heat the coolant in the second stack radiator;

[0032] After that, when the water inlet temperature of the second stack radiator is higher than T ra At -1℃, the electric three-way valve is closed.

[0033] On the basis of the above technical solution, for startup under high ambient temperature, only the water pump is turned on, and the specific steps include:

[0034] The water pump is turned on, and the thermostat is used to control only the fuel cell cooling circuit to be connected to the fuel cell stack. The electronic fan at the first stack radiator is turned off, and the electronically controlled three-way valve is closed.

[0035] On the basis of the above technical solution, in the fuel cell stack cooling control logic, initially only the electronic fan at the first stack radiator works, specifically:

[0036] When the fuel cell stack is started, the water pump is turned on, and only the fuel cell cooling circuit is connected to the fuel cell stack. The electronic fans at the first and second stack radiators are turned off, and the electronically controlled three-way valve is closed.

[0037] Then when the fuel cell stack inlet water temperature T fw Greater than temperature T fw1 When the electronic fan at the first stack radiator operates at a first set speed;

[0038] Then, as the inlet water temperature of the fuel cell stack increases, the speed of the electronic fan at the first stack radiator increases linearly, and when the inlet water temperature of the fuel cell stack T fw Rise to T fw2 At +1°C, the electronic fan at the first stack radiator operates at the second set speed.

[0039] On the basis of the above technical solution, the opening of the electronically controlled three-way valve and the dynamic adjustment of the speed of the electronic fan at the second stack radiator in the fuel cell stack cooling control logic are specifically as follows:

[0040] When the speed of the electronic fan at the first stack radiator is the second set speed and the inlet water temperature of the fuel cell stack is T fw Greater than T fw2 At +1°C, the opening of the electronically controlled three-way valve is dynamically adjusted based on the outlet water temperature of the first and second stack radiators and the total flow rate of the fuel cell cooling circuit;

[0041] At the same time, when the outlet water temperature of the second stack radiator is greater than T fw2 When the temperature is -1℃, the electronically controlled three-way valve is fully opened. Then, according to the inlet water temperature T fw Adjust the speed of the electronic fan at the second stack radiator. Specifically, when the inlet water temperature of the fuel cell stack is T fw Reach T fw2 When the temperature is -1℃, read the speed of the electronic fan at the second stack radiator. Then, as the water inlet temperature T fw As the temperature of the water inlet of the fuel cell stack increases, the speed of the electronic fan at the second stack radiator increases linearly, and when the water inlet temperature of the fuel cell stack T fw Rise to T fw2At +1°C, the electronic fan at the second stack radiator operates at the fourth set speed.

[0042] On the basis of the above technical solution, the opening of the electronically controlled three-way valve is dynamically adjusted based on the outlet water temperature of the first stack radiator, the outlet water temperature of the second stack radiator and the total flow of the fuel cell cooling circuit. The specific adjustment formula is:

[0043] Q2=(T w1o -T fw2 +1) / (T w1o -T w2O )*Q

[0044] Among them, Q2 represents the opening of the electric three-way valve, T w1o Indicates the outlet water temperature of the first stack radiator, T w2O It represents the outlet water temperature of the second stack radiator, and Q represents the total flow rate of the fuel cell cooling circuit.

[0045] Compared with the existing technology, the advantages of the present invention are: by integrating the first stack radiator and the air-conditioning condenser, and integrating the second stack radiator, the water-cooled unit condenser and the motor and high-voltage accessory radiator, and sharing a fan, while meeting the heat dissipation of the stack, the layout is compact and the cost is low; by setting an electronically controlled three-way valve, the intervention timing and intervention degree of the second stack radiator can be adjusted, reducing the influencing variables of the fuel cell thermal management system cooling control, simplifying the control strategy, and improving the system control accuracy; when the fuel cell is cold-started at low temperature, the waste heat of the motor, high-voltage accessories, power battery, etc. is fully utilized to assist the PTC water heater in heating the stack, effectively shortening the stack startup time, and making the whole vehicle more energy-efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0047] Figure 1 Schematic diagram of the structure of an integrated fuel cell vehicle thermal management system in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. It should be noted that the orientation or position relationship indicated by the terms "upper" and "lower" is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a communication between the two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising the element.

[0049] The present invention mainly solves the problems of low integration, difficult layout, high cost and imprecise control of fuel cell thermal management system, and effectively reduces the energy consumption of the whole vehicle and improves the driving range. Figure 1 As shown, an embodiment of the present invention provides an integrated fuel cell vehicle thermal management system, including a fuel cell cooling circuit and a fuel cell heating circuit. The integrated fuel cell vehicle thermal management system includes heating and cooling functions, enabling the fuel cell stack to start up quickly and maintain the fuel cell stack within the appropriate operating temperature range during operation.

[0050] The fuel cell cooling circuit includes a main cooling water circuit for connecting the fuel cell stacks in series, and a branch cooling water circuit connected in parallel to the main cooling water circuit via an electronically controlled three-way valve. The main cooling water circuit is equipped with a first fuel cell stack radiator and a water pump, while the branch cooling water circuit is equipped with a second fuel cell stack radiator. The branch cooling water circuit can be connected to the main cooling water circuit under the control of the electronically controlled three-way valve.

[0051] The fuel cell heating circuit is connected to the fuel cell cooling circuit at both ends of the fuel cell stack, and one end of the fuel cell heating circuit is connected to the thermostat provided on the fuel cell cooling circuit. The fuel cell heating circuit is equipped with a PTC (positive temperature coefficient thermistor) water heater. That is, under the control of the thermostat, the fuel cell heating circuit is connected to the fuel cell stack, and the PTC water heater heats the fuel cell stack. Alternatively, the fuel cell heating circuit is disconnected from the fuel cell stack, and only the fuel cell cooling circuit is connected to the fuel cell stack.

[0052] In the present invention, electronic fans are installed at both the first and second stack radiators. The first stack radiator is located at the front of the vehicle and is also equipped with an air conditioning condenser. The second stack radiator is also equipped with a motor and high-voltage accessory radiator, as well as a water-cooled unit condenser. The first stack radiator, air conditioning condenser, and electronic fan at the first stack radiator together form the first radiator assembly, fully utilizing headwind for cooling. The first stack radiator is the primary stack radiator.

[0053] The second stack radiator, water-cooled unit condenser, motor, and high-voltage accessory radiator together form the second radiator assembly. The second stack radiator is the auxiliary radiator of the stack. Figure 1 In the figure, the right side of the fuel cell stack is the inlet and the left side is the outlet.

[0054] In the present invention, both ends of the first stack radiator are provided with temperature sensors; both ends of the second stack radiator are provided with temperature sensors; and both ends of the fuel cell stack are provided with temperature sensors.

[0055] In the present invention, a pressure sensor, a filter and a deionizer are also provided on the fuel cell cooling circuit, and an expansion water tank is also connected to the fuel cell cooling circuit; the water-cooled unit condenser is the condenser of the battery water-cooled unit of the power battery, and the motor and high-voltage accessory radiator is connected to the motor and high-voltage accessories.

[0056] An embodiment of the present invention provides an integrated fuel cell vehicle thermal management control method for controlling the integrated fuel cell vehicle thermal management system described above. The integrated fuel cell vehicle thermal management control method specifically includes fuel cell stack startup heating control logic and fuel cell stack cooling control logic.

[0057] In the present invention, the fuel cell stack startup heating control logic is specifically as follows:

[0058] For startup at low ambient temperatures, the water pump is turned on and initially heated by a PTC water heater. The vehicle's waste heat is then used to heat the coolant in the second stack radiator.

[0059] For startup at room temperature, the water pump is turned on to use the waste heat of the vehicle to heat the coolant in the second stack radiator;

[0060] For startup at higher ambient temperatures, only the water pump is turned on.

[0061] In the present invention, the fuel cell stack cooling control logic is specifically as follows:

[0062] Initially, only the electronic fan at the first stack radiator works, and as the water inlet temperature of the fuel cell stack rises, the electronic fan at the second stack radiator works, and the opening of the electronically controlled three-way valve and the speed of the electronic fans at the first and second stack radiators are dynamically adjusted.

[0063] In the embodiment of the present invention, when starting up at a low ambient temperature, the water pump is turned on and initially heated by a PTC water heater. Then, the waste heat of the vehicle is used to heat the coolant in the second stack radiator. The specific steps include:

[0064] S101: The water pump and the PTC water heater are turned on, the water path is controlled by the thermostat, and the PTC water heater heats the fuel cell stack; that is, the coolant passing through the fuel cell stack is heated by the PTC water heater.

[0065] S102: When the water inlet temperature of the fuel cell stack is higher than the temperature T fw0 When the temperature is low, the PTC water heater is turned off, the thermostat is adjusted, and the fuel cell cooling circuit enters circulation. At this time, the electronic fan at the first stack radiator is off, and when the air outlet temperature of the motor and high-voltage accessory radiator is low, the electronically controlled three-way valve is closed.

[0066] S103: Then when the outlet air temperature of the motor and high-voltage accessory radiator is T ra When the temperature is higher than the set temperature, the electronically controlled three-way valve opens and the electronic fan at the second stack radiator starts to work, using the hot air passing through the water-cooled unit condenser, motor, and high-voltage accessory radiator to heat the coolant in the second stack radiator, making full use of the vehicle's waste heat to assist in heating the stack and shortening the stack startup time.

[0067] S104: When the water inlet temperature of the second stack radiator is higher than T ra At -1℃, the electronically controlled three-way valve is closed, and the electronic fan at the second stack radiator continues to operate according to the heat dissipation requirements of the motor, high-voltage accessory radiator, and water-cooled unit condenser.

[0068] In the embodiment of the present invention, for startup under normal temperature, the water pump is turned on and the coolant in the second stack radiator is heated using the waste heat of the vehicle. The specific steps include:

[0069] S201: The water pump is turned on, and only the fuel cell cooling circuit is connected to the fuel cell stack through the thermostat control, and the electronic fan at the first stack radiator is turned off; at this time, the electronic fan at the first stack radiator is in the off state, and when the air outlet temperature of the motor and high-voltage accessory radiator is low, the electronically controlled three-way valve is closed.

[0070] S202: Then when the outlet air temperature of the motor and high-voltage accessory radiator is T ra When the temperature is higher than the set temperature, the electronically controlled three-way valve opens and the electronic fan at the second stack radiator starts to work, using the hot air passing through the water-cooled unit condenser, motor, and high-voltage accessory radiator to heat the coolant in the second stack radiator, making full use of the vehicle's waste heat to assist in heating the stack and shortening the stack startup time.

[0071] S203: When the water inlet temperature of the second stack radiator is higher than T ra At -1℃, the electronically controlled three-way valve is closed, and the electronic fan at the second stack radiator continues to operate according to the heat dissipation requirements of the motor, high-voltage accessory radiator, and water-cooled unit condenser.

[0072] In the embodiment of the present invention, for startup under high ambient temperature, only the water pump is turned on, and the specific steps include:

[0073] The water pump is turned on, and the thermostat is used to control only the fuel cell cooling circuit to be connected to the fuel cell stack. The electronic fan at the first stack radiator is turned off, and the electronically controlled three-way valve is closed.

[0074] In the embodiment of the present invention, in the fuel cell stack cooling control logic, initially only the electronic fan at the first stack radiator works, specifically:

[0075] S301: After the fuel cell stack is started and operating normally, the water pump is turned on, only the fuel cell cooling circuit is connected to the fuel cell stack, the electronic fans at the first stack radiator and the second stack radiator are turned off, and the electronically controlled three-way valve is closed;

[0076] S302: Then when the fuel cell stack inlet water temperature T fw Greater than temperature T fw1 When the fan is turned on, the electronic fan at the first stack radiator operates at a first set speed; the first set speed is the speed when the rated cooling capacity of the cab is met. Since the cooling capacity of the air-conditioned cab is relatively small, the speed is low at this time and the heat dissipation of the first stack radiator is small. During the process of the fan speed changing from off to the first set speed, the stack cooling water temperature fluctuates less.

[0077] S303: Then, as the inlet water temperature of the fuel cell stack increases, the speed of the electronic fan at the first stack radiator increases linearly, and when the inlet water temperature of the fuel cell stack T fw Rise to T fw2When the temperature is +1℃, the electronic fan at the first stack radiator operates at the second set speed. That is, after the electronic fan at the first stack radiator starts to rotate, the speed is linearly adjusted as the inlet water temperature of the fuel cell stack rises. When the inlet water temperature of the fuel cell stack is T fw Rise to T fw2 At +1°C, the electronic fan at the first stack radiator operates at a second set speed, which is the maximum speed of the electronic fan at the first stack radiator.

[0078] In the embodiment of the present invention, the opening of the electronically controlled three-way valve and the dynamic adjustment of the speed of the electronic fan at the second stack radiator in the fuel cell stack cooling control logic are specifically as follows:

[0079] When the speed of the electronic fan at the first stack radiator is the second set speed and the inlet water temperature of the fuel cell stack is T fw Greater than T fw2 At +1°C, the opening of the electronically controlled three-way valve is dynamically adjusted based on the outlet water temperature of the first and second stack radiators and the total flow rate of the fuel cell cooling circuit;

[0080] At the same time, when the outlet water temperature of the second stack radiator is greater than T fw2 When the temperature is -1℃, the electronically controlled three-way valve is fully opened. Then, according to the inlet water temperature T fw Adjust the speed of the electronic fan at the second stack radiator. Specifically, when the inlet water temperature of the fuel cell stack is T fw Reach T fw2 When the temperature is -1℃, read the speed of the electronic fan at the second stack radiator. Then, as the water inlet temperature T fw As the temperature of the water inlet of the fuel cell stack increases, the speed of the electronic fan at the second stack radiator increases linearly, and when the water inlet temperature of the fuel cell stack T fw Rise to T fw2 +1℃, the electronic fan at the second stack radiator operates at the fourth set speed. That is, when the electronically controlled three-way valve is fully opened, according to the inlet water temperature T fw The fourth set speed is the maximum speed of the electronic fan at the second stack radiator.

[0081] By using the above method, the water inlet temperature of the fuel cell stack is always maintained at T fw2 +1 and T fw1 -1, meeting the heat dissipation requirements of the fuel cell stack.

[0082] The following describes in detail the fuel cell stack startup heating control logic of the present invention with reference to specific examples.

[0083] When the ambient temperature is lower than 15°C and the fuel cell stack is started, the water pump and the PTC water heater are turned on. The thermostat controls only the PTC water heater to heat the fuel cell stack. At this time, the electronic fan at the first fuel cell stack radiator is off. When the inlet water temperature of the fuel cell stack is higher than 15°C, the PTC water heater is turned off, the thermostat is adjusted, and the fuel cell cooling circuit enters the cycle. When the outlet air temperature of the motor and high-voltage accessory radiator is T ra When the temperature exceeds 45°C, the electronically controlled three-way valve opens, and the electronic fan at the second stack radiator operates. This uses the hot air passing through the water-cooled unit condenser, the motor, and the high-voltage accessory radiator to heat the coolant in the second stack radiator, fully utilizing the vehicle's waste heat to assist in heating the stack and shortening its startup time. Subsequently, when the water inlet temperature to the second stack radiator exceeds 44°C, the electronically controlled three-way valve closes, and the electronic fan at the second stack radiator continues to operate to meet the cooling needs of the motor, high-voltage accessory radiator, and the water-cooled unit condenser.

[0084] When the ambient temperature is 15-25℃, the stack is started, the water pump is turned on, and the thermostat controls only the fuel cell cooling circuit to be connected to the fuel cell stack, and the electronic fan at the first stack radiator is turned off; then, when the air outlet temperature T ra When the temperature exceeds 45°C, the electronically controlled three-way valve opens, and the electronic fan at the second stack radiator operates. This uses the hot air passing through the water-cooled unit condenser, the motor, and the high-voltage accessory radiator to heat the coolant in the second stack radiator, fully utilizing the vehicle's waste heat to assist in heating the stack and shortening its startup time. Subsequently, when the water inlet temperature to the second stack radiator exceeds 44°C, the electronically controlled three-way valve closes, and the electronic fan at the second stack radiator continues to operate to meet the cooling needs of the motor, high-voltage accessory radiator, and the water-cooled unit condenser.

[0085] For startup at an ambient temperature above 25°C, the water pump is turned on, and only the fuel cell cooling circuit is connected to the fuel cell stack through the thermostat control. The electronic fan at the first stack radiator is turned off, and the electronically controlled three-way valve is closed.

[0086] In the present invention, the opening of the electronically controlled three-way valve is dynamically adjusted based on the outlet water temperature of the first stack radiator, the outlet water temperature of the second stack radiator, and the total flow rate of the fuel cell cooling circuit. The specific adjustment formula is:

[0087] Q2=(T w1o -T fw2 +1) / (T w1o -T w2O )*Q

[0088] Among them, Q2 represents the opening of the electric three-way valve, T w1o Indicates the outlet water temperature of the first stack radiator, T w2OIt represents the outlet water temperature of the second stack radiator, and Q represents the total flow rate of the fuel cell cooling circuit.

[0089] The fuel cell stack cooling control logic of the present invention is described in detail below with reference to specific examples.

[0090] When the fuel cell stack is started and running normally, only the water pump is turned on, only the fuel cell cooling circuit is connected to the fuel cell stack, the electronic fans at the first and second stack radiators are turned off, and the electronically controlled three-way valve is closed. fw When the temperature is greater than 71℃, the electronic fan at the first stack radiator is set to 30% Ⅰmax To work, n Ⅰmax The maximum speed of the electronic fan at the first stack radiator is 30% of the speed of the electronic fan at the first stack radiator. Ⅰmax When the air conditioning condenser can meet the rated cooling capacity of the cab, the cooling capacity of the air-conditioned cab is relatively small, the speed is low at this time, the heat dissipation of the first stack radiator is small, and the fan is turned from off to 30%n Ⅰmax During the rotation speed process, the stack cooling water temperature fluctuates slightly.

[0091] After the electronic fan at the first stack radiator starts to rotate, the speed is linearly adjusted as the fuel cell stack inlet water temperature rises. When the fuel cell stack inlet water temperature T fw When the temperature rises to 74℃, the electronic fan at the first stack radiator rotates at a speed n Ⅰmax to carry out the work.

[0092] When the speed of the electronic fan at the first stack radiator is n Ⅰmax , and the fuel cell stack water inlet temperature T fw When it is greater than 74℃, read the outlet water temperature T of the first stack radiator w1o , the outlet water temperature of the second stack radiator T w2O and the total flow rate Q of the fuel cell cooling circuit, T under different systems and different working conditions w1o 、T w2O , Q are different, according to the formula Q2=(T w1o -72) / (T w1o -T w2O )*Q, real-time adjustment of the opening of the electric three-way valve.

[0093] At the same time, when the outlet water temperature of the second stack radiator is greater than 72°C, the electronically controlled three-way valve is fully opened, and the fuel cell stack inlet water temperature T fw Adjust the speed of the electronic fan at the second stack radiator. When the inlet water temperature of the fuel cell stack is T fwWhen the temperature reaches 72℃, the electronically controlled three-way valve is fully opened, and the speed of the electronic fan at the second stack radiator is adjusted to meet the cooling requirements of the motor, high-voltage accessory radiator, and water-cooled unit condenser. fw As the temperature of the fuel cell stack water inlet T increases, the speed of the electronic fan at the second stack radiator increases linearly. fw When the temperature rises to 74° C., the electronic fan at the second stack radiator operates at a fourth set speed, which is the maximum speed of the electronic fan at the second stack radiator.

[0094] Through the above control strategy, the inlet water temperature of the fuel cell stack is always maintained between 70°C and 74°C during operation, meeting the heat dissipation requirements of the fuel cell stack.

[0095] The integrated fuel cell vehicle thermal management control method of the embodiment of the present invention integrates the first stack radiator and the air-conditioning condenser, and integrates the second stack radiator, the water-cooling unit condenser and the motor and high-voltage accessory radiator, and shares a fan. While meeting the heat dissipation requirements of the stack, the layout is compact and the cost is low. By setting an electronically controlled three-way valve, the intervention timing and intervention degree of the second stack radiator can be adjusted, reducing the variables affecting the cooling control of the fuel cell thermal management system, simplifying the control strategy, and improving the system control accuracy. When the fuel cell is cold-started at low temperature, the waste heat of the motor, high-voltage accessories, power battery, etc. is fully utilized to assist the PTC water heater in heating the stack, effectively shortening the stack startup time and making the entire vehicle more energy-efficient.

[0096] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0097] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0098] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. An integrated fuel cell vehicle thermal management system, characterized in that: include: A fuel cell cooling circuit, comprising a main cooling water circuit for connecting the fuel cell stack in series, and a branch cooling water circuit connected in parallel to the main cooling water circuit via an electronically controlled three-way valve, the main cooling water circuit being provided with a first fuel cell stack radiator and a water pump, and the branch cooling water circuit being provided with a second fuel cell stack radiator; A fuel cell heating circuit, wherein the fuel cell heating circuit is connected to the fuel cell cooling circuit at both ends of the fuel cell stack, and one end of the fuel cell heating circuit is connected to a thermostat provided on the fuel cell cooling circuit, and the fuel cell heating circuit is provided with a PTC water heater; The first stack radiator and the second stack radiator are both equipped with electronic fans, and the first stack radiator is arranged at the front of the vehicle. The first stack radiator is also equipped with an air conditioning condenser, and the second stack radiator is also equipped with a motor and high-voltage accessory radiator, as well as a water-cooled unit condenser. The electronically controlled three-way valve dynamically adjusts its opening according to the fuel cell stack inlet water temperature, the first stack radiator outlet water temperature, and the second stack radiator outlet water temperature. The adjustment formula is: Q2=(T w1o -T fw2 +1) / ( T w1o -T w2O )*Q Among them, Q2 represents the opening of the electric three-way valve, T w1o Indicates the outlet water temperature of the first stack radiator, T w2O represents the outlet water temperature of the second stack radiator, and Q represents the total flow rate of the fuel cell cooling circuit; The thermostat is used to control the timing of connecting to the fuel cell heating circuit. When the inlet water temperature of the fuel cell stack is lower than T fw0 When the water inlet temperature is higher than T fw0 When the PTC water heater is turned off and switched to cooling cycle; Among them, in the fuel cell stack cooling control logic, initially only the electronic fan at the first stack radiator works, specifically: When the fuel cell stack is started, the water pump is turned on, and only the fuel cell cooling circuit is connected to the fuel cell stack. The electronic fans at the first and second stack radiators are turned off, and the electronically controlled three-way valve is closed. Then when the fuel cell stack inlet water temperature T fw Greater than temperature T fw1 When the electronic fan at the first stack radiator operates at a first set speed; Then, as the inlet water temperature of the fuel cell stack increases, the speed of the electronic fan at the first stack radiator increases linearly, and when the inlet water temperature of the fuel cell stack T fw Rise to T fw2 At +1°C, the electronic fan at the first stack radiator operates at the second set speed; Among them, for the fuel cell stack cooling control logic, the electronically controlled three-way valve opening and the dynamic adjustment of the electronic fan speed at the second stack radiator are specifically as follows: When the speed of the electronic fan at the first stack radiator is the second set speed and the inlet water temperature of the fuel cell stack is T fw Greater than T fw2 At +1°C, the opening of the electronically controlled three-way valve is dynamically adjusted based on the outlet water temperature of the first and second stack radiators and the total flow rate of the fuel cell cooling circuit; At the same time, when the outlet water temperature of the second stack radiator is greater than T fw2 When the temperature is -1℃, the electronically controlled three-way valve is fully opened. Then, according to the inlet water temperature T fw Adjust the speed of the electronic fan at the second stack radiator. Specifically, when the inlet water temperature of the fuel cell stack is T fw Reach T fw2 When the temperature is -1℃, read the speed of the electronic fan at the second stack radiator. Then, as the water inlet temperature T fw As the temperature of the water inlet of the fuel cell stack increases, the speed of the electronic fan at the second stack radiator increases linearly, and when the water inlet temperature of the fuel cell stack T fw Rise to T fw2 At +1°C, the electronic fan at the second stack radiator operates at the fourth set speed.

2. The integrated fuel cell vehicle thermal management system according to claim 1, characterized in that: Temperature sensors are provided at both ends of the first stack radiator; Temperature sensors are provided at both ends of the second stack radiator; Temperature sensors are provided at both ends of the fuel cell stack.

3. The integrated fuel cell vehicle thermal management system according to claim 1, characterized in that: The fuel cell cooling circuit is also provided with a pressure sensor, a filter and a deionizer, and the fuel cell cooling circuit is also connected to an expansion water tank; The water-cooling unit condenser is the condenser of the battery water-cooling unit of the power battery, and the motor and high-voltage accessory radiator is connected to the motor and high-voltage accessories.

4. An integrated fuel cell vehicle thermal management control method for controlling the integrated fuel cell vehicle thermal management system according to any one of claims 1 to 3, characterized in that: Specifically including fuel cell stack startup heating control logic and fuel cell stack cooling control logic; The fuel cell stack startup heating control logic is specifically as follows: For startup at low ambient temperatures, the water pump is turned on and initially heated by a PTC water heater. The vehicle's waste heat is then used to heat the coolant in the second stack radiator. For startup at room temperature, the water pump is turned on to use the waste heat of the vehicle to heat the coolant in the second stack radiator; For startup at high ambient temperature, only the water pump is turned on; The fuel cell stack cooling control logic is specifically as follows: Initially, only the electronic fan at the first stack radiator works, and as the water inlet temperature of the fuel cell stack rises, the electronic fan at the second stack radiator works, and the opening of the electronically controlled three-way valve and the speed of the electronic fans at the first and second stack radiators are dynamically adjusted.

5. The integrated fuel cell vehicle thermal management control method according to claim 4, characterized in that: For startup at a low ambient temperature, the water pump is turned on, and the PTC water heater is initially used for heating. Then, the waste heat of the vehicle is used to heat the coolant in the second stack radiator. The specific steps include: The water pump and PTC water heater are turned on, and the PTC water heater is controlled by the thermostat to heat the fuel cell stack; Then when the water inlet temperature of the fuel cell stack is higher than the temperature T fw0 When the PTC water heater is turned off, the thermostat is adjusted and the fuel cell cooling circuit enters circulation; Then when the outlet temperature of the motor and high-voltage accessories radiator is T ra When the temperature is higher than the set temperature, the electronically controlled three-way valve opens, and the electronic fan at the second stack radiator starts to work, using the hot air passing through the water-cooled unit condenser, motor, and high-voltage accessory radiator to heat the coolant in the second stack radiator; After that, when the water inlet temperature of the second stack radiator is higher than T ra At -1℃, the electric three-way valve is closed.

6. The integrated fuel cell vehicle thermal management control method according to claim 4, characterized in that: For startup under normal temperature, the water pump is turned on to heat the coolant in the second stack radiator using the waste heat of the vehicle. The specific steps include: The water pump is turned on, and the thermostat controls only the fuel cell cooling circuit to be connected to the fuel cell stack, and the electronic fan at the first stack radiator is turned off; Then when the outlet temperature of the motor and high-voltage accessories radiator is T ra When the temperature is higher than the set temperature, the electronically controlled three-way valve opens, and the electronic fan at the second stack radiator starts to work, using the hot air passing through the water-cooled unit condenser, motor, and high-voltage accessory radiator to heat the coolant in the second stack radiator; After that, when the water inlet temperature of the second stack radiator is higher than T ra At -1℃, the electric three-way valve is closed.

7. The integrated fuel cell vehicle thermal management control method according to claim 4, characterized in that: For startup at a high ambient temperature, only the water pump is turned on. The specific steps include: The water pump is turned on, and the thermostat is used to control only the fuel cell cooling circuit to be connected to the fuel cell stack. The electronic fan at the first stack radiator is turned off, and the electronically controlled three-way valve is closed.

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