Fuel cell heavy-duty engine thermal management system and cold start control method

Abstract

The present application relates to a kind of fuel cell heavy truck engine thermal management system and cold start control method, the cooling liquid outlet of battery stack is connected with the input end of thermostat by high-temperature circulating water pump;Thermostat is sequentially connected with water-heat PTC, hydrogen heater, hydrogen heater is connected with battery stack, forming first circulation loop;Thermostat is connected with three-way valve and is connected with first radiator in series, first radiator is connected with battery stack by hydrogen heater, forming second circulation loop;Three-way valve is connected with first radiator and second radiator in parallel, and is connected with hydrogen heater in series, hydrogen heater is connected with battery stack, forming third circulation loop;Thermal management controller determines thermostat, three-way valve opening time and shunt ratio based on the cooling liquid inlet and outlet water temperature of battery stack, power, determines the cooling liquid flow rate flowing through water-heat PTC, first radiator, second radiator;Realize the smooth and rapid rise of temperature, shorten the cold start process, improve user experience.

Description

Technical Field

[0001] This invention relates to the field of commercial vehicle technology, and in particular to a thermal management system and cold start control method for a fuel cell heavy-duty truck engine. Background Technology

[0002] Fuel cell heavy-duty trucks are a key area for future development due to their advantages such as short refueling time, long driving range, and environmental friendliness. However, fuel cell engines are highly sensitive to operating temperature, and different power outputs have different optimal operating temperatures. Therefore, quickly raising the coolant temperature to the required temperature for the fuel cell engine is crucial for improving its cold start rate. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a thermal management system and cold start control method for fuel cell heavy-duty truck engines.

[0004] This invention is achieved using the following technical solution:

[0005] A thermal management system for a fuel cell heavy-duty truck engine, characterized in that it includes a battery stack, a high-temperature circulating water pump, a thermostat, a hydrothermal PTC, a hydrogen heater, a three-way valve, a first radiator, and a second radiator.

[0006] The coolant outlet of the battery stack is connected to the input end of the thermostat via a high-temperature circulating water pump; the thermostat is provided with thermostat output end one and thermostat output end two.

[0007] The output terminal of the thermostat is connected in sequence to the hydrothermal PTC and the hydrogen heater. The hydrogen heater is connected to the coolant inlet of the battery stack to form a first circulation loop.

[0008] The three-way valve is provided with a three-way valve input end, a three-way valve output end one, and a three-way valve output end two;

[0009] The output terminal 2 of the thermostat is connected to the input terminal of the three-way valve. The output terminal 1 of the three-way valve is connected in series with the first radiator. The first radiator is connected to the coolant inlet of the battery stack through the hydrogen heater to form a second circulation loop.

[0010] The first and second output terminals of the three-way valve are connected in parallel with the first and second radiators, respectively, and then connected in series with the hydrogen heater. The hydrogen heater is connected to the coolant inlet of the battery stack to form a third circulation loop.

[0011] And a thermal management controller, which is used to acquire the output power of the fuel cell engine and the inlet and outlet temperatures of the battery stack in real time when the fuel cell vehicle is cold-started at low temperature; and based on the inlet and outlet water temperatures and power of the battery stack, determine the opening time and flow ratio of the thermostat and the three-way valve, and determine the flow rate of the coolant flowing through the hydrothermal PTC, the first radiator and the second radiator.

[0012] Furthermore, the thermal management controller includes a data acquisition unit;

[0013] The data acquisition unit includes a first temperature sensor, which is located at the coolant outlet of the battery stack and is used to acquire the coolant outlet temperature T1 of the battery stack.

[0014] The second temperature sensor is located at the coolant inlet of the battery stack and is used to obtain the inlet temperature T2 of the coolant entering the battery stack.

[0015] The third temperature sensor is installed on the pipeline connected in series with the hydrogen heater after the first and second radiators are connected in parallel, and is used to obtain the temperature T3 of the coolant flowing out of the mixture of the first and second radiators after parallel connection.

[0016] The fourth temperature sensor is located at the coolant outlet of the first radiator and is used to obtain the temperature T4 of the coolant flowing out of the first radiator.

[0017] The fifth temperature sensor is located at the coolant outlet of the second radiator and is used to obtain the temperature T5 of the coolant flowing out of the second radiator.

[0018] Furthermore, the thermal management controller also includes a data processing unit, which determines the opening time and flow split ratio of the thermostat and three-way valve based on the inlet and outlet water temperatures and power of the battery stack, and determines the flow rate of the coolant flowing through the hydrothermal PTC, the first radiator, and the second radiator.

[0019] Furthermore, the fuel cell is a hydrogen fuel cell, a solid oxide fuel cell, or a direct methanol fuel cell.

[0020] A cold start control method, applied to the thermal management system of a fuel cell heavy-duty truck engine as described above, includes the following steps:

[0021] S1, after the vehicle is charged with high voltage in a low-temperature environment, obtain the maximum allowable charging power of the power battery Wmax;

[0022] If Wmax < Mmin, then execute S2; if Wmax ≥ Mmin, then execute S3.

[0023] Where Mmin is the minimum output power of the fuel cell engine;

[0024] S2, heat up the power battery until Wmax ≥ Mmin, then start the fuel cell and execute S3;

[0025] S3, after the fuel cell receives the start-up enable, obtain the coolant outlet temperature T1 of the fuel cell stack;

[0026] If T1 < T1min, then execute S4; if T1 ≥ T1min, then execute S5.

[0027] Where T1min is the minimum temperature threshold for battery stack startup;

[0028] S4, heat the battery stack until T1≥T1min, the battery stack starts, and S5 is executed;

[0029] S5, the battery stack is started and the battery stack is heated until T1≥T2min, then S6 is executed;

[0030] Where T2min is the coolant inlet temperature at which the fuel cell has the minimum output power;

[0031] S6: Obtain the real-time output power of the fuel cell engine and obtain the real-time fuel cell operating temperature Tymin based on the operating power; if the difference between the coolant inlet temperature T2 of the battery stack and the real-time fuel cell operating temperature Tymin is less than TXX, the thermostat opens.

[0032] S7, obtain the real-time output power of the fuel cell engine, and obtain the real-time fuel cell operating temperature Txu and the outlet temperature T4 of the first radiator based on the operating power;

[0033] Based on the difference between the outlet temperature T4 of the first radiator and the real-time operating temperature Txu of the fuel cell, the three-way valve opens when the difference between T4 and Txu is less than TCX.

[0034] Furthermore, S4 specifically involves: opening thermostat output terminal one, closing thermostat output terminal two, operating the high-temperature circulating water pump at the minimum power supply frequency, starting the hydrothermal PTC, and starting the battery stack until T1 ≥ T1min.

[0035] Furthermore, S5 specifically involves: starting the battery stack, continuously turning on the hydrothermal PTC until T1 ≥ T2 min, at which point the hydrothermal PTC is turned off.

[0036] Furthermore, S6 also includes: obtaining the current coolant inlet temperature T2 of the battery stack and the coolant temperature T3 of the mixture flowing out of the first radiator and the second radiator after being connected in parallel;

[0037] The opening degree of the thermostat is determined based on the difference between T2 and T3;

[0038] If the difference between T2 and T3 is less than 3℃, then both thermostat output terminals one and two will be opened.

[0039] Furthermore, the coolant temperature T4 flowing out of the first radiator and the coolant temperature T5 flowing out of the second radiator are obtained;

[0040] The opening degree of the three-way valve is determined based on the difference between T4 and T5;

[0041] If the difference between T4 and T5 is less than 2℃, then both the first and second output terminals of the three-way valve will be fully open.

[0042] Compared with the prior art, the present invention has the following beneficial technical effects:

[0043] A dual-heat dissipation structure consisting of a first radiator and a second radiator is adopted. Based on the coolant temperature during cold start, the opening sequence and degree of the three-way valve and thermostat are determined to improve the coolant heating rate and reduce the cold start time of fuel cell heavy-duty trucks. Based on the coolant temperature at the inlet of the fuel cell stack and the temperature difference between the coolant outlets of the first and second radiators, the flow split ratio of the three-way valve and thermostat is calculated, thereby reducing the cooling temperature fluctuation at the inlet of the fuel cell stack coolant. This enables adaptive adjustment of the coolant addition amount according to changes in coolant temperature, achieving a stable and rapid temperature rise, shortening the cold start process, and improving the user experience. Attached Figure Description

[0044] Figure 1 This is a logic diagram of the thermal management system in this invention;

[0045] Figure 2 This is a flowchart of the cold start control method in this invention;

[0046] Figure 3 This is a flowchart illustrating the opening of the thermostat in this invention;

[0047] Figure 4 This is a flowchart of the three-way valve opening process in this invention.

[0048] Figure Labels

[0049] 1. Battery stack; 2. High-temperature circulating water pump; 3. Thermostat; 4. Hydrothermal PTC; 5. Hydrogen heater; 6. Three-way valve; 7. First radiator; 8. Second radiator; 9. First temperature sensor; 10. Second temperature sensor; 11. Third temperature sensor; 12. Fourth temperature sensor; 13. Fifth temperature sensor. Detailed Implementation

[0050] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0051] Example 1

[0052] A thermal management system for a fuel cell heavy-duty truck engine includes a battery stack 1, a high-temperature circulating water pump 2, a thermostat 3, a hydrothermal PTC 4, a hydrogen heater 5, a three-way valve 6, a first radiator 7, and a second radiator 8.

[0053] The coolant outlet of the battery stack 1 is connected to the input end of the thermostat 3 via a high-temperature circulating water pump 2; the thermostat 3 is provided with a thermostat output end one and a thermostat output end two.

[0054] The output of the thermostat is connected in sequence to the hydrothermal PTC4 and the hydrogen heater 5. The hydrogen heater 5 is connected to the coolant inlet of the battery stack 1 to form the first circulation loop.

[0055] The three-way valve is provided with a three-way valve inlet, a three-way valve outlet one, and a three-way valve outlet two;

[0056] The output end 2 of the thermostat is connected to the input end of the three-way valve. The output end 1 of the three-way valve is connected in series with the first radiator 7. The first radiator 7 is connected to the coolant inlet of the battery stack 1 through the hydrogen heater 5 to form a second circulation loop.

[0057] The first and second output terminals of the three-way valve are connected in parallel with the first radiator 7 and the second radiator 8 respectively, and then connected in series with the hydrogen heater 5. The hydrogen heater 5 is connected to the coolant inlet of the battery stack 1 to form a third circulation loop.

[0058] And a thermal management controller, which is used to acquire the output power of the fuel cell engine and the inlet and outlet temperatures of the coolant in the battery stack 1 in real time when the fuel cell vehicle is cold-started at low temperature; and based on the inlet and outlet water temperatures and power of the coolant in the battery stack 1, determine the opening time and flow ratio of the thermostat 3 and the three-way valve 6, and determine the flow rate of the coolant flowing through the hydrothermal PTC 4, the first radiator 7 and the second radiator 8.

[0059] The thermal management controller includes a data acquisition unit;

[0060] The data acquisition unit includes a first temperature sensor 9, which is located at the coolant outlet of the battery stack 1 and is used to acquire the coolant outlet temperature T1 of the battery stack.

[0061] The second temperature sensor 10 is located at the coolant inlet of the battery stack 1 and is used to obtain the coolant inlet temperature T2 of the battery stack.

[0062] The third temperature sensor 11 is located on the pipeline connected in series with the hydrogen heater 5 after the first radiator 7 and the second radiator 8 are connected in parallel, and is used to obtain the temperature T3 of the coolant flowing out of the mixture of the first radiator 7 and the second radiator 8 after being connected in parallel.

[0063] The fourth temperature sensor 12 is located at the coolant outlet of the first radiator 7 and is used to obtain the temperature T4 of the coolant flowing out of the first radiator 7.

[0064] The fifth temperature sensor 13 is located at the coolant outlet of the second radiator 8 and is used to obtain the temperature T5 of the coolant flowing out of the second radiator 8.

[0065] The thermal management controller also includes a data processing unit. Based on the coolant inlet and outlet water temperatures and power of the battery stack 1, the data processing unit determines the opening time and flow ratio of the thermostat 3 and the three-way valve 6, and determines the coolant flow rate through the hydrothermal PTC 4, the first radiator 7, and the second radiator 8.

[0066] Fuel cells can be hydrogen fuel cells, solid oxide fuel cells, or direct methanol fuel cells.

[0067] Example 2

[0068] A cold start control method, applied to the thermal management system of any of the above-mentioned fuel cell heavy-duty truck engines, includes the following steps:

[0069] S1, after the vehicle is charged with high voltage in a low-temperature environment, obtain the maximum allowable charging power of the power battery Wmax;

[0070] If Wmax < Mmin, then execute S2; if Wmax ≥ Mmin, then execute S3.

[0071] Where Mmin is the minimum output power of the fuel cell engine;

[0072] S2, heat up the power battery until Wmax ≥ Mmin, then start the fuel cell and execute S3;

[0073] S3, when the fuel cell receives the start-up enable, obtain the coolant outlet temperature T1 of the battery stack 1;

[0074] If T1 < T1min, then execute S4; if T1 ≥ T1min, then execute S5.

[0075] Where T1min is the minimum temperature threshold for starting up battery stack 1;

[0076] S4, heat battery stack 1 until T1≥T1min, battery stack 1 starts up, execute S5;

[0077] S5, Battery stack 1 is started, and the temperature of battery stack 1 is increased until T1≥T2min, then S6 is executed;

[0078] Where T2min is the coolant inlet temperature at which the fuel cell has the minimum output power;

[0079] S6, obtain the real-time output power of the fuel cell engine, and obtain the real-time fuel cell operating temperature Tymin based on the operating power; based on the difference between the coolant inlet temperature T2 of the battery stack 1 and the real-time fuel cell operating temperature Tymin, if the difference between T2 and Tymin is less than TXX, the thermostat 3 opens.

[0080] S7, obtain the real-time output power of the fuel cell engine, and obtain the real-time fuel cell operating temperature Txu and the outlet temperature T4 of the first radiator 7 based on the operating power;

[0081] Based on the difference between the outlet temperature T4 of the first radiator 7 and the real-time operating temperature Txu of the fuel cell, if the difference between T4 and Txu is less than TCX, the three-way valve 6 will open.

[0082] S4 specifically means: thermostat output terminal one is open, thermostat output terminal two is closed, high-temperature circulating water pump 2 runs at the minimum power supply frequency, hydrothermal PTC4 starts, until T1≥T1min, battery stack 1 starts.

[0083] S5 specifically refers to: starting the battery stack 1, continuously turning on the hydrothermal PTC4 until T1≥T2min, at which point the hydrothermal PTC4 is turned off.

[0084] S6 also includes: obtaining the current coolant inlet temperature T2 of the battery stack 1 and the coolant temperature T3 of the mixture flowing out of the first radiator 7 and the second radiator 8 after being connected in parallel;

[0085] The opening degree of thermostat 3 is determined based on the difference between T2 and T3;

[0086] If the difference between T2 and T3 is less than 3℃, then both thermostat output terminals one and two will be opened.

[0087] Get the coolant temperature T4 flowing out of the first radiator 7 and the coolant temperature T5 flowing out of the second radiator 8;

[0088] The opening degree of the three-way valve 6 is determined based on the difference between T4 and T5;

[0089] If the difference between T4 and T5 is less than 2℃, then both the first and second output terminals of the three-way valve will be fully open.

Claims

1. A thermal management system for a fuel cell heavy-duty truck engine, characterized in that, Includes battery stack (1), high temperature circulating water pump (2), thermostat (3), hydrothermal PTC (4), hydrogen heater (5), three-way valve (6), first radiator (7), and second radiator (8); The coolant outlet of the battery stack (1) is connected to the input end of the thermostat (3) via a high-temperature circulating water pump (2); the thermostat (3) is provided with a thermostat output end one and a thermostat output end two. The output end of the thermostat is connected in sequence to the hydrothermal PTC (4) and the hydrogen heater (5). The hydrogen heater (5) is connected to the coolant inlet of the battery stack (1) to form a first circulation loop. The three-way valve is provided with a three-way valve input terminal, a three-way valve output terminal one, and a three-way valve output terminal two; The output end 2 of the thermostat is connected to the input end of the three-way valve. The output end 1 of the three-way valve is connected in series with the first radiator (7). The first radiator (7) is connected to the coolant inlet of the battery stack (1) through the hydrogen heater (5) to form a second circulation loop. The first and second output terminals of the three-way valve are connected in parallel with the first radiator (7) and the second radiator (8) respectively, and then connected in series with the hydrogen heater (5). The hydrogen heater (5) is connected to the coolant inlet of the battery stack (1) to form a third circulation loop. And a thermal management controller, which is used to acquire the output power of the fuel cell engine and the inlet and outlet temperatures of the coolant in the battery stack (1) in real time when the fuel cell vehicle is cold-started at low temperature; and based on the inlet and outlet water temperatures and power of the coolant in the battery stack (1), determine the opening time and flow ratio of the thermostat (3) and the three-way valve (6), and determine the flow rate of the coolant flowing through the hydrothermal PTC (4), the first radiator (7) and the second radiator (8).

2. The fuel cell heavy-duty truck engine thermal management system according to claim 1, characterized in that, The thermal management controller includes a data acquisition unit; The data acquisition unit includes a first temperature sensor (9), which is located at the coolant outlet of the battery stack (1) and is used to acquire the coolant outlet temperature T1 of the battery stack. The second temperature sensor (10) is located at the coolant inlet of the battery stack (1) and is used to obtain the coolant inlet temperature T2 of the battery stack. The third temperature sensor (11) is located on the pipeline connected in series with the hydrogen heater (5) after the first radiator (7) and the second radiator (8) are connected in parallel. It is used to obtain the temperature T3 of the coolant flowing out of the first radiator (7) and the second radiator (8) after being connected in parallel. The fourth temperature sensor (12) is located at the coolant outlet of the first radiator (7) and is used to obtain the temperature T4 of the coolant flowing out of the first radiator (7). The fifth temperature sensor (13) is located at the coolant outlet of the second radiator (8) and is used to obtain the temperature T5 of the coolant flowing out of the second radiator (8).

3. The fuel cell heavy-duty truck engine thermal management system according to claim 2, characterized in that, The thermal management controller also includes a data processing unit. Based on the inlet and outlet water temperatures and power of the battery stack (1), the data processing unit determines the opening time and flow ratio of the thermostat (3) and the three-way valve (6), and determines the flow rate of the coolant flowing through the hydrothermal PTC (4), the first radiator (7), and the second radiator (8).

4. The thermal management system for a fuel cell heavy-duty truck engine according to claim 3, characterized in that, The fuel cell is a hydrogen fuel cell, a solid oxide fuel cell, or a direct methanol fuel cell.

5. A cold start control method, applied to the thermal management system of a fuel cell heavy-duty truck engine as described in any one of claims 1-3, characterized in that, Includes the following steps: S1, after the vehicle is charged with high voltage in a low-temperature environment, obtain the maximum allowable charging power of the power battery Wmax; If Wmax < Mmin, then execute S2; if Wmax ≥ Mmin, then execute S3. Where Mmin is the minimum output power of the fuel cell engine; S2, heat up the power battery until Wmax ≥ Mmin, then start the fuel cell and execute S3; S3, when the fuel cell receives the start-up enable, obtain the coolant outlet temperature T1 of the battery stack (1); If T1 < T1min, then execute S4; if T1 ≥ T1min, then execute S5. Where T1min is the minimum temperature threshold for starting the battery stack (1); S4, heat the battery stack (1) until T1≥T1min, the battery stack (1) starts, and S5 is executed; S5, the battery stack (1) is started and the battery stack (1) is heated until T1≥T2min, then S6 is executed; Where T2min is the coolant inlet temperature at which the fuel cell has the minimum output power; S6, obtain the real-time output power of the fuel cell engine, and obtain the real-time fuel cell operating temperature Tymin according to the operating power; according to the size of the coolant inlet temperature T2 of the battery stack (1) and the real-time fuel cell operating temperature Tymin, if the difference between T2 and Tymin is less than TXX, the thermostat (3) is opened. S7, obtain the real-time output power of the fuel cell engine, and obtain the real-time fuel cell operating temperature Txu and the outlet temperature T4 of the first radiator (7) based on the operating power; Based on the difference between the outlet temperature T4 of the first radiator (7) and the real-time operating temperature Txu of the fuel cell, if the difference between T4 and Txu is less than TXX, the three-way valve (6) opens.

6. The cold start control method according to claim 5, characterized in that, Specifically, S4 is as follows: the thermostat output terminal one is opened, the thermostat output terminal two is closed, the high-temperature circulating water pump (2) operates at the minimum power supply frequency, the hydrothermal PTC (4) is started, until T1≥T1min, the battery stack (1) is started.

7. The cold start control method according to claim 5, characterized in that, Specifically, S5 is as follows: the battery stack (1) is started, the hydrothermal PTC (4) is continuously turned on until T1≥T2min, and then the hydrothermal PTC (4) is turned off.

8. The cold start control method according to claim 5, characterized in that, The S6 further includes: obtaining the current coolant inlet temperature T2 of the battery stack (1) and the coolant temperature T3 of the mixture flowing out of the first radiator (7) and the second radiator (8) after being connected in parallel; The opening degree of the thermostat (3) is determined based on the difference between T2 and T3; If the difference between T2 and T3 is less than 3℃, then both thermostat output terminals one and two will be opened.

9. The cold start control method according to claim 5, characterized in that, The temperature of the coolant flowing out of the first radiator (7) T4 and the temperature of the coolant flowing out of the second radiator (8) T5 are obtained. The opening degree of the three-way valve (6) is determined based on the difference between T4 and T5; If the difference between T4 and T5 is less than 2℃, then both the first and second output terminals of the three-way valve will be fully open.

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