Fuel cell tractor trailer tandem radiator cooling system and method

Abstract

The present application belongs to the technical field of fuel cell heat dissipation control. A fuel cell tractor trailer interconnection type double radiator cooling system and method are proposed. The fuel cell stack outlet is connected with a water pump. The water pump outlet is divided into two paths. One path passes through an auxiliary valve, a thermostat and a base radiator to form a base cooling circuit, and returns to the fuel cell stack. The other path passes through a flow regulating valve, a tractor and a trailer side liquid supply connector, a trailer side interconnection valve, an auxiliary radiator, a check throttle element, a trailer and a tractor side liquid return connector, and a tractor side interconnection valve to return to the fuel cell stack, forming an auxiliary cooling circuit that can be interconnected. The controller is electrically connected with the water pump and each control valve to realize intelligent control of the on-off and flow of the cooling circuit. The present application can meet the heat dissipation requirements of the fuel cell under different working conditions through flexible interconnection of the tractor and trailer radiators, and improve the cooling efficiency and operating stability.

Description

Technical Field

[0001] This invention relates to the field of fuel cell heat dissipation control technology, and in particular to a fuel cell tractor-trailer connected dual radiator cooling system and method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] As a crucial solution for zero-emission transportation of heavy-duty commercial vehicles, fuel cell tractor trucks rely heavily on their thermal management systems, which directly impact the lifespan of the fuel cell stack and the overall vehicle performance. Due to the separate structure of the tractor and trailer, and the significant load variations and complex aerodynamic characteristics of the trailer, traditional cooling solutions typically only place basic heat dissipation modules at the tractor's cab. Under long-distance uphill climbing or high-load conditions, the limited heat dissipation area at the cab often fails to meet the heat dissipation requirements of the high-power fuel cell stack. While some existing technologies attempt to add auxiliary cooling devices to the trailer, limitations in the reliability of the fluid connection between the tractor and trailer, the coordination of the control system, and spatial layout have prevented the development of a mature, integrated, and efficient cooling architecture. This has resulted in the overall vehicle thermal management potential not being fully realized, limiting the continuous operation capability of fuel cell heavy-duty trucks under extreme conditions.

[0004] Existing fuel cell tractor cooling systems suffer from a major technical challenge when dealing with high heat loads: the inability to dynamically connect and coordinate the heat dissipation resources of the tractor and trailer. Traditional solutions often involve the tractor's main circuit and the trailer's auxiliary circuit operating independently or lacking a reliable, rapid connection mechanism. This prevents the efficient distribution of coolant to the trailer's auxiliary radiator when enhanced cooling is needed, leading to overload of the tractor's main radiator and idle trailer cooling resources. Furthermore, the lack of an integrated control strategy for trailer connection status and dual-circuit flow distribution makes it difficult for the system to accurately adjust the proportion of coolant flowing through the trailer's branch circuits based on the real-time heat generation of the fuel cell stack. This easily results in stack temperature fluctuations due to circuit switching lag or uneven flow distribution, failing to meet the stringent requirements of fuel cell stacks for high responsiveness and stability in their cooling systems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a fuel cell tractor-trailer interconnected dual radiator cooling system and method, which can effectively solve the problem that the heat dissipation resources of the tractor and trailer cannot be dynamically connected and coordinated in the existing technology, and realizes flexible connection and disconnection of the tractor main circuit (i.e., the first circulation circuit) and the trailer auxiliary circuit (i.e., the second circulation circuit).

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a fuel cell tractor-trailer connected dual radiator cooling system.

[0007] A fuel cell tractor-trailer connected dual radiator cooling system includes a basic radiator, a water pump, a thermostat, a cross-vehicle connection valve group, a first liquid supply connector, a second liquid supply connector, a first liquid return connector, a second liquid return connector, an auxiliary radiator, a trailer-side connecting valve, a check valve, and a controller. The cooling pipe outlet of the fuel cell stack, the water pump, the first inlet of the cross-vehicle connection valve group, the first outlet of the cross-vehicle connection valve group, the thermostat, the base radiator, and the cooling pipe inlet of the fuel cell stack are connected in series through pipes to form the first circulation loop. The cooling pipe outlet of the fuel cell stack, water pump, first inlet of the cross-vehicle connection valve group, second outlet of the cross-vehicle connection valve group, first liquid supply connector, second liquid supply connector, trailer side connecting valve, auxiliary radiator, check valve, first return liquid connector, second return liquid connector, second inlet of the cross-vehicle connection valve group, third outlet of the cross-vehicle connection valve group, and cooling pipe inlet of the fuel cell stack are connected in series through pipes to form a second circulation loop; The controller is electrically connected to the water pump, the crossover valve assembly, and the trailer-side connecting valve, and is configured to dynamically control the water pump speed, the opening and closing of the crossover valve assembly and the trailer-side connecting valve.

[0008] In one implementation of the first aspect of the present invention, the cross-vehicle connection valve group includes an auxiliary valve, a flow regulating valve, and a tractor-side connecting valve, and the cooling pipe outlet of the fuel cell stack is connected to the inlet of the water pump. The outlet of the water pump is connected to the inlet of the auxiliary valve and the inlet of the flow regulating valve, respectively. The outlet of the auxiliary valve is connected to the inlet of the thermostat. The outlet of the thermostat is connected to the inlet of the base radiator. The outlet of the base radiator is connected to the inlet of the cooling pipe of the fuel cell stack. The outlet of the flow regulating valve is connected to the second liquid supply connector on the trailer side via the first liquid supply connector on the tractor side. The second liquid supply connector is connected to the inlet of the trailer-side connecting valve. The outlet of the trailer-side connecting valve is connected to the inlet of the auxiliary radiator. The outlet of the auxiliary radiator is connected to the inlet of the first return fluid connector on the trailer side through a check valve throttling element; the outlet of the first return fluid connector is connected to the inlet of the second return fluid connector on the tractor side, and the outlet of the second return fluid connector is connected to the cooling pipe inlet of the fuel cell stack through a connecting valve on the tractor side.

[0009] In one implementation of the first aspect of the present invention, the device further includes a coupling detection device and a tractor fan. The coupling detection device is disposed at the connection between the tractor and the trailer and is used to detect the coupling status and locking effectiveness. The coupling detection device is electrically connected to the controller. The tractor fan is disposed next to the base radiator and the control terminal of the tractor fan is electrically connected to the controller.

[0010] In one implementation of the first aspect of the present invention, a temperature sensor is further included. The temperature sensor is disposed at the coolant outlet and coolant inlet of the fuel cell stack, and the signal output terminal of the temperature sensor is electrically connected to the controller.

[0011] In one implementation of the first aspect of the present invention, a trailer fan for heat dissipation is provided at the location of the auxiliary radiator, and an auxiliary pump is provided on the pipeline between the auxiliary radiator and the check valve throttling element. The trailer fan and the auxiliary pump are electrically connected to the controller respectively.

[0012] In one implementation of the first aspect of the present invention, the thermostat is provided with a bypass outlet, which is directly connected to the cooling pipe inlet of the fuel cell stack, so as to allow the coolant to flow back directly without passing through the base radiator under low temperature conditions.

[0013] Secondly, the present invention provides a method for cooling fuel cell tractor trailers with interconnected dual radiators.

[0014] A method for cooling a fuel cell tractor-trailer with interconnected dual radiators, utilizing the fuel cell tractor-trailer interconnected dual radiator cooling system of the first aspect of this invention, includes the following steps: When the tractor fails to tow the trailer or the hook-up is invalid, it enters single-loop mode: the controller controls the auxiliary valve to open and controls the second circulation loop to close. The coolant flows out from the fuel cell stack, is pumped by the water pump, and flows through the opened cross-vehicle connection valve group and thermostat. After entering the base radiator for heat dissipation, it returns to the fuel cell stack. When the connection is valid, the connection between the first liquid supply connector and the second liquid supply connector, as well as between the first liquid return connector and the second liquid return connector, is valid; and when the coolant outlet temperature is greater than the first set threshold, or the power of the fuel cell stack is greater than the second set threshold, or the coolant outlet temperature rise rate is greater than the third set threshold, the system enters dual-loop mode: The controller controls the opening of the first and second circulation loops. The coolant is pumped by the water pump and then divided into two paths. The two coolant paths merge and return to the fuel cell stack.

[0015] In one implementation of the second aspect of the present invention, in a dual-loop control mode, the controller estimates the heat generated by the fuel cell stack based on the power of the fuel cell stack and determines the target heat exchange requirement. The controller calculates the target coolant flow rate based on the target heat exchange requirement, the specific heat capacity of the coolant, and the difference between the coolant outlet temperature and the coolant inlet temperature. The cross-vehicle access valve group includes a flow regulating valve located on the second circulation loop. The controller calculates the target opening degree of the flow regulating valve based on the heat generated by the fuel cell stack, vehicle speed and ambient temperature, so that the heat dissipation share undertaken by the trailer auxiliary branch is matched with the current heat load and heat exchange capacity. The controller outputs commands to adjust the speed of the water pump to track the target coolant flow rate, and also outputs commands to adjust the opening of the flow control valve to track the target opening.

[0016] As a further limitation of the second aspect of the present invention, the controller uses one of the empirical function method, the lookup table method or the model calculation method to estimate the heat generation of the fuel cell stack based on the power of the fuel cell stack; the target coolant flow rate is the ratio of the target heat exchange demand to the product of the specific heat capacity and temperature difference of the coolant.

[0017] In one implementation of the second aspect of the present invention, the controller monitors in real time the coupling status between the tractor and the trailer, the connection status between the first fluid supply connector and the second fluid supply connector and between the first fluid return connector and the second fluid return connector, the electrical connection status between the controller and each component, and the pressure of the pipeline through which the coolant flows. When an abnormal connection status, abnormal connection status, electrical connection interruption, abnormal pressure of the coolant pipeline, or leakage risk is detected, the controller controls the flow regulating valve to close to zero opening and controls the second circulation loop to close.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention innovatively proposes a fuel cell tractor-trailer interconnected dual radiator cooling system, which effectively solves the problem of the inability to dynamically connect and coordinate the heat dissipation resources of the tractor and trailer in the prior art. By setting up a controllable liquid circuit switching network composed of flow regulating valves, trailer-side interconnecting valves, and tractor-side interconnecting valves, and combining the integrated electrical connection of the water pump and various valves by the controller, flexible connection and disconnection of the tractor's main circuit and the trailer's auxiliary circuit are realized. When the connection is detected to be effective and enhanced heat dissipation is required, the controller can precisely adjust the opening of the flow regulating valve to divert part of the high-temperature coolant to the auxiliary radiator on the trailer side for heat dissipation, and then return it to the fuel cell stack through the interconnecting valve. This breaks through the bottleneck of the limited area of ​​the radiator on the front of the vehicle, makes full use of the heat dissipation potential of the trailer space, and significantly improves the continuous heat dissipation capacity of the whole vehicle under extreme conditions such as heavy load climbing.

[0019] Thanks to the system's precise control over dual-loop flow distribution, this invention avoids the temperature fluctuation problems of fuel cell stacks caused by loop switching lag or uneven flow distribution in traditional solutions. The controller can dynamically adjust the ratio of coolant flowing through the basic radiator and auxiliary radiator according to the real-time heat generation demand of the fuel cell stack, ensuring precise matching between the two heat dissipation loads and the heat load of the fuel cell stack. This active collaborative control mechanism based on hardware architecture not only eliminates the phenomenon of idle trailer heat dissipation resources but also ensures the stability of coolant temperature, effectively preventing adverse effects on fuel cell stack performance and lifespan caused by local overheating or severe temperature fluctuations, and significantly improving the response speed and control accuracy of the thermal management system.

[0020] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0022] Figure 1 A schematic diagram of a fuel cell tractor-trailer connected dual radiator cooling system provided as an exemplary embodiment of the present invention; Figure 2 A schematic flowchart of a fuel cell tractor-trailer connected dual radiator cooling method provided as an exemplary embodiment of the present invention; Figure 3 A schematic diagram of the electrical connections of a controller provided for an exemplary embodiment of the present invention; Among them, 1. Tractor; 11. Fuel cell stack; 12. Base radiator; 13. Water pump; 14. Thermostat; 15. Crossover valve assembly; 151. Auxiliary valve; 152. Flow regulating valve; 153. Tractor side connecting valve; 16. First fluid supply connector; 17. Second fluid return connector; 2. Trailer; 21. Auxiliary radiator; 22. Second fluid supply connector; 23. Trailer side connecting valve; 24. First fluid return connector; 25. Check valve throttling element; 3. Controller. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] Currently, single-radiator cooling systems are widely used in fuel cell tractor vehicles. These systems are mostly designed with the radiator based on the peak heat load of traction conditions, resulting in large radiator sizes and high fan power. To cover high heat load scenarios such as heavy traction and hill climbing, the radiator heat exchange area must be increased and the fan power increased. Under non-traction (light load) conditions, the excessively large radiator generates additional wind resistance, and the high-power fan operation produces unnecessary parasitic energy consumption, leading to a significant reduction in overall vehicle efficiency. Simultaneously, the large radiator increases the difficulty of vehicle layout. Existing systems cannot dynamically adapt to changes in operating conditions, relying solely on the fixed cooling capacity of the radiator itself, without additional cooling channels. When the heat load reaches its peak during traction, the radiator's cooling capacity is insufficient, causing the fuel cell stack coolant temperature to surge, resulting in low thermal safety margins and a risk of fuel cell stack damage. Under non-traction conditions, excessive cooling capacity further exacerbates wind resistance and wastes energy. The existing system lacks an adaptive switching mechanism for operating conditions, and does not have heat dissipation control logic that is linked to the trailer's attachment status. It cannot distinguish between "independent operation" and "traction operation" operating conditions, and cannot meet the core requirements of both operating conditions (energy efficiency of independent operation and thermal safety of traction operation).

[0026] In view of the problems existing in the existing solutions, this implementation proposes a fuel cell tractor-trailer interconnected dual radiator cooling system. By designing an interconnected dual radiator system of "tractor basic heat dissipation + trailer auxiliary heat dissipation" and the corresponding dynamic control method, the heat dissipation capacity can be increased as needed, taking into account both low energy consumption in non-traction conditions and high thermal safety margin in traction conditions, while ensuring the independent operation capability of the tractor and the reliability in the docking condition.

[0027] The specific connection relationships of the various components of the system are as follows: Figure 1 As shown, the tractor 1 is equipped with a fuel cell stack 11, a basic radiator 12, a water pump 13, a thermostat 14, a crossover valve group 15, an auxiliary valve 151, a flow regulating valve 152, a tractor side connecting valve 153, a first liquid supply connector 16, and a second liquid return connector 17. The trailer 2 is equipped with an auxiliary radiator 21, a second liquid supply connector 22, a trailer side connecting valve 23, a first liquid return connector 24, and a check valve 25.

[0028] The cooling pipe outlet of the fuel cell stack 11 is connected to the inlet of the water pump 13. The outlet of the water pump 13 is connected to the inlet of the auxiliary valve 151 and the inlet of the flow regulating valve 152. The outlet of the auxiliary valve 151 is connected to the inlet of the thermostat 14. The outlet of the thermostat 14 is connected to the inlet of the base radiator 12. The outlet of the base radiator 12 is connected to the inlet of the fuel cell stack 11. The outlet of the flow regulating valve 152 is connected to the second liquid supply connector 22 on the trailer side through the first liquid supply connector 16 on the tractor side. The second liquid supply connector 22 is connected to the inlet of the trailer-side connecting valve 23. The outlet of the trailer-side connecting valve 23 is connected to the inlet of the auxiliary radiator 21. The outlet of the auxiliary radiator 21 is connected to the inlet of the first return fluid connector 24 on the trailer side via a check valve throttling element 25; the outlet of the first return fluid connector 24 is connected to the inlet of the second return fluid connector 17 on the tractor side, and the outlet of the second return fluid connector 17 is connected to the inlet of the fuel cell stack 11 via the tractor side connecting valve 153; the controller 3 is electrically connected to the water pump 13, the auxiliary valve 151, the flow regulating valve 152, the tractor side connecting valve 153, and the trailer side connecting valve 23, respectively.

[0029] This implementation also includes a coupling detection device, which is installed at the connection between the tractor 1 and the trailer 2 to detect the coupling status and locking effectiveness. The coupling detection device is electrically connected to the controller 3, and the coupling detection device is introduced to monitor the mechanical connection status in real time, providing the controller 3 with a key input signal of "whether coupling is in place", preventing the dual-loop mode from being mistakenly activated when coupling is not in place or the coupling is unreliable, and ensuring the system logic safety.

[0030] This implementation also includes a tractor fan, which is located next to the base radiator 12. The control terminal of the tractor fan is connected to the controller 3, thereby enhancing the heat dissipation effect of the base radiator 12.

[0031] This implementation also includes a temperature sensor, which is installed at the coolant outlet and coolant inlet of the fuel cell stack 11. The signal output terminal of the temperature sensor is connected to the controller 3. By deploying the temperature sensor, the coolant temperature difference data is collected in real time, providing the controller with accurate thermal load calculation basis and closed-loop control feedback signal, thus realizing precise temperature control.

[0032] In this implementation, a trailer fan for heat dissipation is provided at the location of the auxiliary radiator 21, and an auxiliary pump is provided on the pipeline between the auxiliary radiator 21 and the check throttling element 25 to ensure the circulation effect of the coolant and improve the heat dissipation effect.

[0033] In this implementation, the thermostat 14 is provided with a bypass outlet, which is directly connected to the inlet of the fuel cell stack 11, so that the coolant can flow back directly without passing through the base radiator 12 under low temperature conditions.

[0034] The system implemented in this way includes two loops, specifically: Single-loop mode: Auxiliary valve 151 is open, while flow regulating valve 152, tractor-side connecting valve 153, trailer-side connecting valve 23, and check valve / throttling element 25 are closed. Cooling circuit flow: fuel cell stack 11 → water pump 13 → auxiliary valve 151 open → thermostat 14 → base radiator 12 → fuel cell stack 11. A portion of the coolant flowing into thermostat 14 can flow directly to fuel cell stack 11.

[0035] Dual-loop mode: Auxiliary valve 151 is open, and flow regulating valve 152, tractor-side connecting valve 153, trailer-side connecting valve 23, and check valve 25 are also open. Cooling circuit flow direction: The coolant entering the cross-vehicle connection valve group 15 from the water pump 13 is divided into two parts. The first part flows to the thermostat 14 through the auxiliary valve 151, and then returns to the inlet side of the fuel cell stack 11 through the base radiator 12. The second part flows through the flow regulating valve 152, the first supply connector 16, the second supply connector 22, the trailer-side connecting valve 23, the auxiliary radiator 21, the trailer fan, and the check valve 25, and then flows back to the inlet side of the fuel cell stack 11 through the first return connector 24, the second return connector 17, and the tractor-side connecting valve 153, forming a parallel cooling branch for the dual radiators.

[0036] It should be noted that the trailer fan can be placed near the auxiliary radiator 21 to assist in heat dissipation, i.e., directly blowing on the auxiliary radiator 21, or it can directly blow on the pipeline between the auxiliary radiator 21 and the check throttling element 25 to dissipate heat. Those skilled in the art can choose according to the specific working conditions, which will not be elaborated here.

[0037] Based on the aforementioned fuel cell tractor-trailer connected dual radiator cooling system, this implementation automatically achieves dynamic switching between "independent cooling for the tractor, enhanced cooling under traction conditions, and abnormal isolation protection" via a controller. Furthermore, the control strategy is strongly correlated with the operating parameters of the fuel cell stack 11 to address the heat dissipation problem caused by rapid changes in heat load and high peak heat load under hydrogen fuel cell traction conditions. Figure 2 As shown, the specific process is as follows: S201: Single-loop mode (when not connected or connection is invalid).

[0038] When the attachment detection device detects "untethered trailer" or "attachment invalid," controller 3 outputs a command to close flow regulating valve 152 and tractor-side connecting valve 153, isolating the cross-vehicle circuit. The specific electrical connections of controller 3 are as follows: Figure 3 As shown, the coolant circulates only in a single loop within the tractor unit 1, and is cooled by the base radiator 12, ensuring the tractor unit 1's independent operation capability.

[0039] S202: Connection detection.

[0040] The coupling detection device confirms whether the coupling between the tractor 1 and the trailer 2 is "effective". It determines whether the connection between the first liquid supply connector 16 and the second liquid supply connector 22 and the first liquid return connector 24 and the second liquid return connector 17 is effective. When the coupling is effective and the connection is effective, proceed to step S203.

[0041] S203: Connectivity determination.

[0042] The controller collects the power of fuel cell stack 11. Speed Ambient temperature Coolant outlet temperature With inlet temperature When the coolant outlet temperature The power of the fuel cell stack 11 is greater than the first set threshold. When the temperature rise rate at the coolant outlet exceeds the second set threshold, or exceeds the third set threshold, the system enters dual-loop mode.

[0043] S204: Turn on China Unicom.

[0044] in accordance with Estimate the heat generation of fuel cell stack 11 (Empirical functions, table lookups, or model calculations can be used), followed by the target heat exchange requirement. (Based on the heat generated by the obtained fuel cell stack 11) The calculation is performed using a table lookup method, and the target coolant flow rate (or volumetric flow rate) is calculated. : (1); in, The required flow rate is calculated based on the law of conservation of energy, and the theoretical flow rate is deduced from the heat generation and target temperature difference. This provides a precise feedforward setpoint for water pump control, ensuring that the heat carried away by the cooling medium is in balance with the heat generation of the fuel cell stack 11.

[0045] Optionally, when using model calculations, the heat generation of fuel cell stack 11 can be obtained using the following calculation method. : (2); Optionally, in some other implementations, the target heat exchange requirement is... Besides looking up a table, the following method can also be used to calculate it: (3); in: The heat generation coefficient of fuel cell stack 11 is obtained from the efficiency characteristics of fuel cell stack 11 (usually...). ); Total target heat exchange requirement of the system (unit: W); The actual outlet temperature of the coolant in the fuel cell stack (unit: °C). The target control temperature of the coolant for fuel cell stack 11 (unit: °C). The power feedforward gain coefficient was calibrated through bench testing. The temperature feedback gain coefficient, calibrated through bench testing, is used to eliminate steady-state temperature differences. A composite calculation model of "power feedforward + temperature feedback" is employed here. This model utilizes power to quickly respond to changes in heat generation and uses temperature differences to correct steady-state errors, improving the accuracy of heat load estimation and dynamic response speed, while eliminating the lag inherent in simple feedback control.

[0046] At the same time, the controller calculates the opening degree of the flow regulating valve. This ensures that the heat dissipation portion of the trailer's cooling circuit matches the heat exchange capacity of the fuel cell stack 11, including its heat load level, vehicle speed, and ambient temperature.

[0047] The valve opening can be determined by looking up a table and matching it with the heat load level of the fuel cell stack 11, vehicle speed, and ambient temperature. Alternatively, in some other implementations, the calculation can be performed in the following manner: (4) (5); (6); in, The actual heat dissipation capacity (unit: W) that the main radiator of tractor 1 can handle under the current operating conditions (vehicle speed, fan speed). The remaining heat dissipation required for the auxiliary branch of the trailer (unit: W); The theoretical target split ratio (dimensionless, range 0~1). This is the target opening command for the flow control valve after amplitude limiting (dimensionless, 0 indicates fully closed, 1 indicates fully open). For the amplitude limiting function, when When 0 is taken, The value is 1. Here, the optimal distribution ratio of the trailer branch circuit is dynamically calculated. After deducting the maximum capacity of the main radiator under the current environment, the remaining heat load is distributed to the trailer to maximize the use of existing heat dissipation resources and avoid energy waste caused by over-opening the trailer circuit or overheating caused by under-opening.

[0048] The controller outputs the speed / flow command of water pump 13 to adjust the actual flow rate. track and output flow regulating valve 152 opening degree Make it track Optionally, a "feedforward + feedback" PID control strategy can be adopted to accurately track the pump flow and valve opening respectively.

[0049] Flow control of water pump 13: (7); (8); Opening control of flow regulating valve 152: (9); (10); in, For water pump motor control commands (such as PWM duty cycle or speed commands); For the target coolant flow rate (by (Calculated from the target temperature difference); This is the actual coolant flow rate feedback value; The flow feedforward compensation amount is obtained by looking up a table based on the pump characteristic curve; For the PID proportional, integral, and derivative coefficients of the flow loop; For the flow control valve actuator control commands; For the target valve opening (i.e., the one calculated above) ); This is the actual valve opening feedback value; The PID proportional, integral, and derivative coefficients of the valve position loop are defined; the PID control equations for flow rate and valve are defined, and the deviation between the set value and the actual value is eliminated by the combined action of the proportional, integral, derivative terms and feedforward, ensuring the smoothness and accuracy of pump and valve operation under complex working conditions and suppressing system oscillation.

[0050] S205: Enhanced heat dissipation.

[0051] In this implementation, the speeds of the tractor fan and trailer fan are adjusted separately (or synchronously if an auxiliary pump is configured). Optionally, the tractor fan and trailer fan can be controlled independently in a closed loop, but coordinated speed regulation based on the overall heat load can be performed to balance heat dissipation performance and energy consumption.

[0052] Tractor fan control: (11); Trailer fan control: (12); in, The target rotational speed of the tractor's fan; The target speed for the trailer fan; These are closed-loop PID controllers for the radiators of the tractor 1 and trailer 2, respectively. This refers to the coolant temperature at the outlet of the trailer's auxiliary radiator. Target outlet temperature for trailer auxiliary radiator; As an enabling factor, when hour, (The trailer fan is allowed to operate); when hour, (The trailer fan stops running to avoid wasted energy); An enabling factor based on valve opening is introduced, which allows the trailer fan to run only when the trailer water circuit is open, eliminating energy waste caused by "water without air" or "running without water", and achieving true on-demand heat dissipation.

[0053] The tractor fan and trailer fan independently adjust their speeds based on the real-time heat load of their respective cooling circuits. When the total system heat load is high, both fans operate at high speed simultaneously; when the heat load is low and is mainly borne by the tractor, the trailer fan maintains low speed or stops, thereby achieving a balance between optimal heat dissipation efficiency and minimum energy consumption under all operating conditions.

[0054] Through the aforementioned dual-loop mode, a collaborative control system of "fuel cell stack 11 power / current feedforward + temperature / temperature difference feedback" is formed. This approach can proactively increase the cooling flow rate and trailer branch flow ratio during sudden load changes, suppressing... Upward surge and Exceeding limits and reducing temperature fluctuations caused by relying solely on fan lag regulation.

[0055] In this implementation, when an unhooking trend, lockout anomaly, branch undervoltage, communication anomaly, branch voltage difference anomaly, or leakage risk is detected, the controller 3 immediately retracts the flow regulating valve 152 to [the specified position]. The tractor-side connecting valve 153, trailer-side connecting valve 23, and check valve throttling element 25 are closed to achieve rapid isolation of cross-vehicle branch circuits. The cooling circuit of the tractor 1 remains closed and can output derating or protection commands to the vehicle controller / fuel cell stack 11 controller to ensure thermal safety. Multiple anomaly detection and rapid isolation mechanisms are established. Once a cross-vehicle connection or communication failure is detected, the trailer branch circuit is immediately cut off and the system returns to single-vehicle mode to prevent coolant leakage, vapor lock, or runaway from damaging the fuel cell stack 11 and ensure system safety under extreme abnormal conditions.

[0056] In summary, this implementation separates the heat dissipation requirements of the tractor unit 1 and the trailer unit 2. The tractor unit 1 is only equipped with basic heat dissipation capabilities sufficient for normal / light load conditions, while the trailer unit 2 is equipped with an auxiliary heat dissipation module specifically designed to cover peak traction heat loads. This design eliminates the need to bear the additional wind resistance and parasitic energy consumption caused by peak heat dissipation during non-traction conditions, effectively improving the overall vehicle energy efficiency. At the same time, the basic radiator of the tractor unit 1 does not need to be excessively enlarged, reducing the difficulty of layout and making costs easier to control. Under high traction loads, the heat dissipation capacity of the trailer unit can be added as needed to fully cover peak heat loads and improve thermal safety margins.

[0057] This implementation uses both engagement status and threshold values ​​to adaptively switch between "independent heat dissipation" and "connected enhanced heat dissipation" modes. This balances the needs of the tractor unit while ensuring thermal safety under traction conditions, making it suitable for all operating scenarios. During peak heat load periods, this mode effectively reduces the temperature surge of the coolant, significantly improving the thermal safety margin of the fuel cell stack and ensuring stable system operation under various conditions.

[0058] This implementation employs a coupling interlocking system, a self-sealing quick-connect mechanism, and an abnormal return mechanism. Diversion is only allowed after the coupling / locking detection passes, and the cross-vehicle interface uses a self-sealing quick-connect structure. In abnormal situations, the diversion ratio is forced to approach zero, isolating the trailer branch circuit and allowing the tractor to quickly return to an independent cooling mode. This design can quickly isolate branch circuits during uncoupling and abnormal situations, reducing leakage risks and preventing trailer problems from affecting the tractor's drivability. It also adapts to frequent coupling scenarios, extends maintenance cycles, and enhances engineering practicality.

[0059] This implementation achieves continuous flow control strongly correlated with the fuel cell stack 11 by setting an electronically controlled proportional three-way flow divider valve (i.e., flow regulating valve 152), allowing for continuous adjustment of the flow divider ratio. The system uses the power / current of the fuel cell stack 11 as a feedforward signal, combined with temperature feedback, to coordinate the control of the valve position, pump, and fans at both ends. Compared to on / off switching, this continuous control method is smoother, has less temperature fluctuation, and the control target can be directly aligned with the temperature control requirements of the fuel cell stack 11, further improving temperature control accuracy and system stability.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-radiator cooling system for a fuel cell tractor-trailer, characterized in that, Includes a basic radiator (12), a water pump (13), a thermostat (14), a crossover valve assembly (15), a first liquid supply connector (16), a second liquid supply connector (22), a first liquid return connector (24), a second liquid return connector (17), an auxiliary radiator (21), a trailer-side connecting valve (23), a check valve (25), and a controller (3); The cooling pipe outlet of the fuel cell stack (11), the water pump (13), the first inlet of the cross-vehicle connection valve group (15), the first outlet of the cross-vehicle connection valve group (15), the thermostat (14), the base radiator (12), and the cooling pipe inlet of the fuel cell stack (11) are connected in series through pipes to form a first circulation loop. The cooling pipe outlet of the fuel cell stack (11), the water pump (13), the first inlet of the cross-vehicle connection valve group (15), the second outlet of the cross-vehicle connection valve group (15), the first liquid supply connector (16), the second liquid supply connector (22), the trailer side connecting valve (23), the auxiliary radiator (21), the check valve throttling element (25), the first return liquid connector (24), the second return liquid connector (17), the second inlet of the cross-vehicle connection valve group (15), the third outlet of the cross-vehicle connection valve group (15), and the cooling pipe inlet of the fuel cell stack (11) are connected in series through pipes to form a second circulation loop; The controller (3) is electrically connected to the water pump (13), the cross-vehicle connecting valve group (15) and the trailer-side connecting valve (23) respectively, and is configured to dynamically control the speed of the water pump (13), the opening and closing of the cross-vehicle connecting valve group (15) and the trailer-side connecting valve (23) and the degree of opening.

2. The fuel cell tractor-trailer connected dual radiator cooling system as described in claim 1, characterized in that, The cross-vehicle connection valve group (15) includes an auxiliary valve (151), a flow regulating valve (152), a tractor-side connection valve (153), and the cooling pipe outlet of the fuel cell stack (11) is connected to the inlet of the water pump (13). The outlet of the water pump (13) is connected to the inlet of the auxiliary valve (151) and the inlet of the flow regulating valve (152), respectively. The outlet of the auxiliary valve (151) is connected to the inlet of the thermostat (14). The outlet of the thermostat (14) is connected to the inlet of the base radiator (12). The outlet of the base radiator (12) is connected to the inlet of the cooling pipe of the fuel cell stack (11). The outlet of the flow regulating valve (152) is connected to the second liquid supply connector (22) on the trailer side via the first liquid supply connector (16) on the tractor side. The second liquid supply connector (22) is connected to the inlet of the trailer side connecting valve (23). The outlet of the trailer side connecting valve (23) is connected to the inlet of the auxiliary radiator (21). The outlet of the auxiliary radiator (21) is connected to the inlet of the first return fluid connector (24) on the trailer side through a check valve throttling element (25); the outlet of the first return fluid connector (24) is connected to the inlet of the second return fluid connector (17) on the tractor side; the outlet of the second return fluid connector (17) is connected to the cooling pipe inlet of the fuel cell stack (11) through a tractor side connecting valve (153).

3. The fuel cell tractor-trailer connected dual radiator cooling system as described in claim 1 or 2, characterized in that, It also includes a coupling detection device and a tractor fan. The coupling detection device is set at the connection between the tractor and the trailer to detect the coupling status and locking effectiveness. The coupling detection device is electrically connected to the controller (3). The tractor fan is set next to the base radiator (12). The control end of the tractor fan is electrically connected to the controller (3).

4. The fuel cell tractor-trailer connected dual radiator cooling system as described in claim 1 or 2, characterized in that, It also includes a temperature sensor, which is installed at the coolant outlet and coolant inlet of the fuel cell stack (11), and the signal output terminal of the temperature sensor is electrically connected to the controller (3).

5. The fuel cell tractor-trailer connected dual radiator cooling system as described in claim 1 or 2, characterized in that, A trailer fan for heat dissipation is provided at the location of the auxiliary radiator (21). An auxiliary pump is provided on the pipeline between the auxiliary radiator (21) and the check throttling element (25). The trailer fan and the auxiliary pump are electrically connected to the controller (3).

6. The fuel cell tractor-trailer connected dual radiator cooling system as described in claim 1 or 2, characterized in that, The thermostat (14) is provided with a bypass outlet, which is directly connected to the cooling pipe inlet of the fuel cell stack (11) to allow the coolant to flow back directly without passing through the base radiator (12) under low temperature conditions.

7. A method for cooling a fuel cell tractor-trailer with interconnected dual radiators, characterized in that, The fuel cell tractor-trailer connected dual radiator cooling system according to any one of claims 1-6 includes the following process: When the tractor fails to tow the trailer or the hook-up is invalid, it enters the single-loop mode: the controller (3) controls the auxiliary valve (151) to open and controls the second circulation loop to close. The coolant flows out from the fuel cell stack (11), is pumped by the water pump (13), and flows through the opened cross-vehicle connection valve group (15) and thermostat (14) to enter the base radiator (12) for heat dissipation before returning to the fuel cell stack (11). When the connection is valid, the connection between the first liquid supply connector (16) and the second liquid supply connector (22) and between the first liquid return connector (24) and the second liquid return connector (17) is valid, and when the coolant outlet temperature is greater than the first set threshold, or the power of the fuel cell stack (11) is greater than the second set threshold, or the coolant outlet temperature rise rate is greater than the third set threshold, the dual-loop mode is entered: The controller (3) controls the opening of the first and second circulation loops. The coolant is pumped by the water pump (13) and then divided into two paths. The two coolants merge and return to the fuel cell stack (11).

8. The fuel cell tractor-trailer connected dual radiator cooling method as described in claim 7, characterized in that, In the dual-loop control mode, the controller (3) estimates the heat generated by the fuel cell stack (11) based on the power of the fuel cell stack (11) and determines the target heat exchange requirement. The controller (3) calculates the target coolant flow rate based on the target heat exchange demand, the specific heat capacity of the coolant, and the difference between the coolant outlet temperature and the coolant inlet temperature; The cross-vehicle connection valve group (15) includes a flow regulating valve (152) located on the second circulation loop. The controller (3) calculates the target opening of the flow regulating valve (152) based on the heat generated by the fuel cell stack (11), vehicle speed and ambient temperature, so that the heat dissipation share undertaken by the trailer auxiliary branch is matched with the current heat load and heat exchange capacity. The controller (3) outputs a command to adjust the speed of the water pump (13) to track the target coolant flow rate, and outputs a command to adjust the opening of the flow regulating valve (152) to track the target opening.

9. The fuel cell tractor-trailer connected dual radiator cooling method as described in claim 8, characterized in that, The controller (3) estimates the heat generation of the fuel cell stack (11) based on the power of the fuel cell stack (11) using one of the empirical function method, table lookup method or model calculation method. The target coolant flow rate is the ratio of the target heat exchange requirement to the product of the coolant's specific heat capacity and temperature difference.

10. The fuel cell tractor-trailer connected dual radiator cooling method as described in claim 7, characterized in that, The controller (3) monitors in real time the coupling status between the tractor and the trailer, the connection status between the first liquid supply connector (16) and the second liquid supply connector (22) and between the first liquid return connector (24) and the second liquid return connector (17), the electrical connection status between the controller (3) and each component, and the pressure of the pipeline through which the coolant flows. When an abnormal connection status, abnormal connection status, electrical connection interruption, abnormal pressure of the coolant in the pipeline, or leakage risk is detected, the controller (3) controls the flow regulating valve (152) to close to zero opening and controls the second circulation loop to close.

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