Shift control method for fuel cell electric vehicle and control system thereof

Abstract

The application provides a shift control method and a control system of a fuel cell electric vehicle, and belongs to the technical field of fuel cell electric vehicle control, and solves the problem that the AMT control strategy in the prior art cannot effectively save energy and reduce emissions. The method comprises the following steps: obtaining the throttle opening degree, upshift speed and downshift speed of the AMT shift strategy in the vehicle power system during vehicle driving; based on the target of the lowest fuel consumption per 100 kilometers of the vehicle, the throttle opening degree, upshift speed and downshift speed are optimized in real time; the AMT is controlled to execute the optimized upshift speed and downshift speed to shift, and the fuel cell is controlled to execute the optimized throttle opening degree during shifting; the vehicle power system is calculated according to the optimized throttle opening degree, upshift speed and downshift speed, the optimized fuel consumption per 100 kilometers of the vehicle is output and displayed.

Description

Technical Field

[0001] This invention relates to the field of fuel cell electric vehicle control technology, and in particular to a shift control method and control system for a fuel cell electric vehicle. Background Technology

[0002] In recent years, with the increasing severity of the energy crisis and environmental pollution, countries around the world have introduced corresponding policies to promote the transformation and development of the traditional automobile industry. Fuel cell electric vehicles, combining the advantages of both gasoline and electric vehicles, have experienced rapid development. A fuel cell electric vehicle is a vehicle that uses hydrogen and other fuels, along with oxygen from the air, to generate electricity through an electrochemical reaction in the presence of a catalyst, and uses this electricity as its primary power source.

[0003] The AMT (Automated Manual Transmission) shifting strategy, a key component of fuel cell electric vehicles, affects the vehicle's power and fuel economy. AMT is an electronically controlled mechanical automatic transmission used in fuel cell electric vehicles. Based on a traditional dry clutch and manual gear transmission, it adds an electronic control system, transforming the manual shifting mechanism into an automatic shifting mechanism, thus achieving a stepped mechanical automatic transmission with automatic gear shifting.

[0004] Most existing AMT shifting strategies fail to consider effective energy saving and emission reduction. For example, the shifting control method for fuel cell vehicle transmissions disclosed in Chinese patent CN2022110899583, by adjusting the fuel cell engine power in advance to ensure that the driving motor braking power meets the speed regulation requirements during the speed regulation phase, can avoid shifting failures. However, because the shifting pattern corresponding to this technology is affected by the speed regulation and braking power requirements of the driving motor, the shifting time and shifting pattern are not optimal, and the overall fuel economy of the vehicle may be poor. The AMT shifting control method disclosed in Chinese patent CN202310224786.4 shifts based on the actual engine speed and target speed, and can regulate the temperature and flow of engine coolant. However, this technology also does not consider fuel economy, and the preset temperature threshold may be disturbed or need to be continuously adjusted, increasing the complexity of system control. Summary of the Invention

[0005] Based on the above analysis, the embodiments of the present invention aim to provide a shift control method and control system for fuel cell electric vehicles, in order to solve the problem that the existing AMT control strategy fails to effectively save energy and reduce emissions.

[0006] On one hand, embodiments of the present invention provide a shift control method for a fuel cell electric vehicle, comprising the following steps:

[0007] S1. During vehicle operation, acquire the throttle opening, upshift speed, and downshift speed of the AMT shift strategy in the vehicle power system.

[0008] S2. Based on the goal of minimizing the vehicle's fuel consumption per 100 kilometers, the throttle opening, upshift speed, and downshift speed are optimized in real time.

[0009] S3. Control the AMT to perform optimized upshift and downshift speeds for gear shifting, and control the fuel cell to perform optimized throttle opening during gear shifting;

[0010] S4. Calculate the vehicle's power system based on the optimized throttle opening, upshift speed, and downshift speed, and output and display the optimized fuel consumption per 100 kilometers.

[0011] The beneficial effects of the above technical solution are as follows: This method adopts a two-parameter shift control strategy based on vehicle speed and throttle opening (the throttle is located at the fuel gas inlet of the fuel cell stack), which is stable, reliable, and simple to implement. Optimizing the AMT shift strategy helps improve the vehicle's economy, power, safety, and emissions performance. A correct shift control strategy can ensure smooth vehicle operation, save fuel and reduce emissions, and improve driving comfort.

[0012] Based on further improvements to the above method, the objective function in step S2 optimization is:

[0013] Q min =min[f(x1,x2,x3)],

[0014] In the formula, Q min This represents the vehicle's minimum fuel consumption per 100 kilometers, where x1 is the throttle opening, x2 is the upshift speed, and x3 is the downshift speed.

[0015] The constraints of the objective function include:

[0016] g (j) (x)≥0, j=1, 2, 3,..., m,

[0017] x i 1 ≤x i ≤x i u i = 1, 2, 3

[0018] In the formula, j is the index of the current constraint, m is the total number of constraints, and x is the independent variable in the objective function, including x1, x2, and x3; g (j) (x) represents the j-th constraint; x i 1 For the independent variable x i The lower limit value, x i u For the independent variable x i The upper limit.

[0019] Furthermore, for upshifting, the constraints of the objective function include:

[0020] The maximum speed within 30 minutes is greater than 120 km / h;

[0021] The maximum speed per kilometer is greater than 120 km / h;

[0022] Acceleration time from 0 to 100 km / h is less than 15 seconds.

[0023] Furthermore, for downgrading, the constraints of the objective function include:

[0024] The maximum gradient is greater than 30%.

[0025] Furthermore, step S2 further includes:

[0026] S21. Establish a mathematical relationship model between the vehicle's fuel consumption per 100 kilometers and the throttle opening, upshift speed, and downshift speed of the AMT shift strategy, and determine the coefficients in the above mathematical relationship model through actual measurement data.

[0027] S22. Based on the objective of minimizing the vehicle's fuel consumption per 100 kilometers, the objective function is optimized using a multi-island genetic algorithm to determine the optimized throttle opening, upshift speed, and downshift speed.

[0028] Furthermore, step S22 further includes:

[0029] S221. Set the parameters in the multi-island genetic algorithm, including population size, generation number, number of islands, migration probability, and migration interval;

[0030] S222. Based on the goal of minimizing the vehicle's fuel consumption per 100 kilometers, the objective function is optimized by using a multi-island genetic algorithm with the above parameters set, generating new throttle opening, upshift speed, and downshift speed as a new population.

[0031] S223. Determine the fitness value of the new population, as well as the fuel consumption per 100 kilometers of the vehicle corresponding to the new throttle opening, upshift speed, and downshift speed.

[0032] S224. Determine whether the fitness value of the new population and the fuel consumption per 100 kilometers of the vehicle meet the set optimization termination conditions. If yes, proceed to step S225; otherwise, return to step S221 to reset the parameters in the multi-island genetic algorithm and optimize the objective function again.

[0033] S225. End the optimization process and use the new throttle opening, upshift speed, and downshift speed obtained in step S222 as the optimized throttle opening, upshift speed, and downshift speed output.

[0034] Furthermore, the objective function in step S2 is replaced with:

[0035] Q min =min[f(x1,x2,x3,C,T)],

[0036] In the formula, C is the road characteristic parameter and T is the ambient temperature parameter.

[0037] Furthermore, the shift control method also includes the following steps:

[0038] S5. Obtain the speed regulation and braking power of the drive motor;

[0039] S6. When it is identified that the speed regulation braking power is less than the difference between the set charging power of the power battery and the power generation power of the fuel cell, the power generation power of the fuel cell remains unchanged during the gear shifting process;

[0040] S7. When it is identified that the speed regulation braking power is greater than the difference between the set charging power of the power battery and the power generation power of the fuel cell, the power generation power of the fuel cell is reduced in advance during the gear shifting process.

[0041] Furthermore, the shift control method also includes the following steps:

[0042] S0. Identify whether the working status of the brake pedal, fuel cell, power battery, high-voltage distribution box, and drive motor is normal. If the working status of the brake pedal, fuel cell, power battery, high-voltage distribution box, and drive motor is normal, then execute steps S1 to S4. Otherwise, the vehicle controller sends an alarm message to the vehicle display screen.

[0043] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0044] 1. Based on the multi-island genetic algorithm, the upshift speed, downshift speed, and throttle opening during upshift and downshift in the shift strategy of fuel cell electric vehicles equipped with AMT are optimized to improve the fuel economy of fuel cell electric vehicles.

[0045] 2. This method can provide a reference for optimizing the AMT shifting strategy of fuel cell electric vehicles, and can be combined with other parameters to further formulate a better AMT shifting strategy.

[0046] 3. The optimized energy consumption was reduced by 5.6% compared to the unoptimized state, thus improving energy utilization.

[0047] 4. It can avoid shifting failures and ensure that the braking power of the drive motor meets the speed regulation requirements during the commissioning stage, thus achieving the purpose of shifting safety and comfort.

[0048] On the other hand, embodiments of the present invention provide a fuel cell vehicle control system using the above-described shift control method, including a fuel cell, a drive motor, an AMT (Automated Manual Transmission), a main reducer, a power battery, and a vehicle controller; wherein,

[0049] The power supply terminal of the drive motor is connected to the output terminals of the fuel cell and the power battery, respectively. Its output terminal is connected to the main reducer via the AMT to control the wheel speed of the fuel cell vehicle.

[0050] The output of the vehicle controller is connected to the control terminals of the drive motor, AMT, main reducer, fuel cell, and power battery;

[0051] The vehicle controller pre-stores multiple theoretical shift speeds for the AMT (Automated Manual Transmission) system, including upshift and downshift speeds. These are used to acquire the throttle opening, upshift speed, and downshift speed of the AMT shift strategy within the vehicle's powertrain during operation. Furthermore, based on the goal of minimizing fuel consumption per 100 kilometers, the controller performs real-time optimization of the throttle opening, upshift speed, and downshift speed. It also controls the AMT to execute the optimized upshift and downshift speeds for gear shifting, and controls the fuel cell to execute the optimized throttle opening during shifting. Finally, it performs calculations for the vehicle's powertrain system based on the optimized throttle opening, upshift speed, and downshift speed, outputting and displaying the optimized fuel consumption per 100 kilometers.

[0052] The beneficial effects of the above technical solution are as follows: It presents a power structure for a control system employing a shift control method. This power structure utilizes a two-parameter shift control strategy based on vehicle speed and throttle opening (the throttle is located at the fuel gas inlet of the fuel cell stack), which is stable, reliable, and simple to implement. Optimizing the AMT shift strategy helps improve vehicle economy, power, safety, and emissions performance. A correct shift control strategy can ensure smooth vehicle operation, fuel saving and emission reduction, and improve driving comfort.

[0053] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or essential features of the invention, nor is it intended to limit the scope of the invention. Attached Figure Description

[0054] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0055] Figure 1 A schematic diagram of the steps of the shift control method in Embodiment 1 is shown;

[0056] Figure 2A flowchart illustrating the shift control method of Embodiment 2 is shown;

[0057] Figure 3 A schematic diagram of the calculation process of the optimization method in Example 2 is shown;

[0058] Figure 4 A schematic diagram of the power structure of the fuel cell vehicle control system in Embodiment 2 is shown. Detailed Implementation

[0059] Embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0060] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0061] Gear shifting strategies can be categorized into single-parameter, dual-parameter, three-parameter, and four-parameter shifting based on the number of control parameters. Single-parameter shifting uses vehicle speed as the sole control parameter, shifting gears upon reaching a specified speed. While the control structure is simple, the driver cannot intervene in the shifting process. Three-parameter shifting, compared to two-parameter shifting, adds the vehicle's acceleration parameter, providing a more accurate reflection of the vehicle's actual handling characteristics. However, the development of three-parameter shifting strategies is very complex, resulting in limited engineering applications. Four-parameter shifting adds the throttle opening rate of change to the three-parameter shifting strategy, and currently, its application is limited to theoretical research in engineering vehicles. This invention employs dual-parameter shifting, using vehicle speed and throttle opening as control parameters, offering stability, reliability, and ease of implementation.

[0062] Fuel cells can be any type of fuel cell currently known, such as hydrogen fuel cells, phosphoric acid fuel cells, and alkaline fuel cells. The shifting timing between gears varies according to changes in shifting control parameters; this is called the shifting law. Any combination of input parameters for the shifting law corresponds to a unique output. The problem that the shifting law needs to solve is selecting which parameters to use as control parameters and when to shift gears, which directly affects the vehicle's power and fuel economy.

[0063] Example 1

[0064] One embodiment of the present invention discloses a shift control method for a fuel cell electric vehicle, such as... Figure 1 As shown, it includes the following steps:

[0065] S1. During vehicle operation, acquire the throttle opening, upshift speed, and downshift speed of the AMT shifting strategy in the vehicle power system; wherein, the throttle can be located on the fuel gas input branch and air input branch of the fuel cell stack in the fuel cell system, as described in CN202021235027.6 and CN202010449922.6;

[0066] S2. Based on the goal of minimizing the vehicle's fuel consumption per 100 kilometers (minimum energy consumption), the throttle opening, upshift speed, and downshift speed are optimized in real time. The optimization method is not limited. In addition to the optimization method described in Example 2, the optimization algorithm in existing patents such as CN201910520108 can also be used.

[0067] S3. Control the AMT to perform optimized upshift and downshift speeds for gear shifting, and control the fuel cell to perform optimized throttle opening during gear shifting;

[0068] S4. Calculate the vehicle's power system based on the optimized throttle opening, upshift speed, and downshift speed, and output and display the optimized fuel consumption per 100 kilometers.

[0069] During implementation, the calculation of the vehicle powertrain system is as follows:

[0070] Q = f(x1,x2,x3,M),

[0071] In the formula, Q is the vehicle's fuel consumption per 100 kilometers, x1 is the throttle opening, x2 is the upshift speed, x3 is the downshift speed, M is other parameters considered (including road characteristic parameters, ambient temperature parameters, and weather conditions), and f() is the calibration function, whose parameters can be calibrated through experiments.

[0072] Compared with existing technologies, the shift control method provided in this embodiment adopts a two-parameter shift control strategy based on vehicle speed and throttle opening (the throttle is located at the fuel gas inlet of the fuel cell stack), which is stable, reliable, and simple to implement. Optimizing the AMT shift strategy helps improve the vehicle's economy, power, safety, and emissions performance. A correct shift control strategy can ensure smooth vehicle operation, save fuel and reduce emissions, and improve driving comfort.

[0073] Example 2

[0074] Based on Example 1, and without considering environmental parameters (i.e., sunny weather, normal temperature (not extremely cold or hot weather), and ordinary roads (highways), the objective function in step S2 optimization can be set as:

[0075] Q min =min[f(x1,x2,x3)],

[0076] In the formula, Q min The objective function represents the minimum fuel consumption per 100 kilometers for the vehicle, where x1 is the throttle opening, x2 is the upshift speed, x3 is the downshift speed, and f() is the calibration function. This objective function uses the throttle opening, upshift speed, and downshift speed of the transmission's upshift and downshift curves as optimization variables.

[0077] The vehicle's fuel consumption per 100 kilometers, Q, is:

[0078] Q = f(x1,x2,x3),

[0079] The constraints of the objective function include:

[0080] g (j) (x)≥0, j=1, 2, 3,..., m,

[0081] x i 1 ≤x i ≤x i u i = 1, 2, 3

[0082] In the formula, j is the index of the current constraint, m is the total number of constraints, and x is the independent variable in the objective function, including x1, x2, and x3; g (j) (x) represents the j-th constraint; x i 1 For the independent variable x i The lower limit value, x i u For the independent variable x i The upper limit.

[0083] Preferably, for upshifting, the constraints of the objective function include:

[0084] 1) The maximum speed in 30 minutes is greater than 120 km / h;

[0085] 2) The maximum speed per kilometer is greater than 120 km / h;

[0086] 3) Acceleration time from 0 to 100 km / h is less than 15 seconds.

[0087] Preferably, for downgrading, the constraints of the objective function include:

[0088] 4) The maximum gradient is greater than 30%.

[0089] In summary, there are four important constraints.

[0090] Preferably, step S2 further includes:

[0091] S21. Establish a mathematical relationship model between the vehicle's fuel consumption per 100 kilometers and the throttle opening, upshift speed, and downshift speed of the AMT shift strategy, and determine the coefficients in the above mathematical relationship model through actual measurement data.

[0092] S22. Based on the objective of minimizing the vehicle's fuel consumption per 100 kilometers, the objective function is optimized using a multi-island genetic algorithm to determine the optimized throttle opening, upshift speed, and downshift speed.

[0093] The entire shift control strategy implementation process is as follows: Figure 2 As shown.

[0094] Preferably, such as Figure 3 As shown, step S22 further includes:

[0095] S221. Set the parameters in the multi-island genetic algorithm, including population size, generation number, number of islands, migration probability, and migration interval;

[0096] S222. Based on the goal of minimizing the vehicle's fuel consumption per 100 kilometers, the objective function is optimized by using a multi-island genetic algorithm with the above parameters set, generating new throttle opening, upshift speed, and downshift speed as a new population.

[0097] S223. Determine the fitness value of the new population, as well as the fuel consumption per 100 kilometers of the vehicle corresponding to the new throttle opening, upshift speed, and downshift speed.

[0098] S224. Determine whether the fitness value of the new population and the fuel consumption per 100 kilometers of the vehicle meet the set optimization termination conditions. If yes, proceed to step S225; otherwise, return to step S221 to reset the parameters in the multi-island genetic algorithm and optimize the objective function again.

[0099] S225. End the optimization process and use the new throttle opening, upshift speed, and downshift speed obtained in step S222 as the optimized throttle opening, upshift speed, and downshift speed output.

[0100] Specifically, the optimization algorithm constructs a very high-quality approximation model based on the Kriging interpolation model. Therefore, this interpolation model is used in the optimization method for the configuration approximation model. Then, the optimization method is set as follows: the population size is 10, the number of iterations is 10, and the number of islands is 10. A smaller migration interval is more conducive to the fusion between subpopulations. In addition, a larger migration interval is conducive to the timely propagation of superior individuals to all subpopulations and can also play a good guiding role in the evolutionary direction of the population, which is conducive to improving the accuracy of the solution and the convergence speed of the population. Therefore, the migration interval is set to 2. Since the best individual in each subpopulation is generally regarded as the migrated individual, if the migration rate is selected to be larger, it will be more beneficial to the propagation of superior individuals in the entire population and the convergence speed. However, with the increase in communication channels and the decrease in speedup ratio, the diversity of the population will decrease, which is not conducive to the algorithm's ability to search in multiple directions simultaneously. Therefore, the value of the mobility ratio should be reasonably selected based on experience. In this embodiment, the mobility ratio is 0.5. After setting the corresponding optimization method, the model optimization method is calculated to generate a new optimization population. Its fitness value and objective function value are optimized and calculated. It is then determined whether the termination condition is met. If the corresponding termination condition is met, the population is unlocked.

[0101] New shifting strategies can be generated by optimizing the throttle opening, upshift speed, and downshift speed.

[0102] During the optimization process, the changes in the objective function can be monitored in real time to obtain the optimization process of the objective function under different optimization strategies. This invention takes the lowest fuel consumption per 100 kilometers as the objective and the vehicle's power performance as the constraint. The upshift and downshift speeds and throttle opening in the AMT shift strategy are selected as optimization variables to establish an optimization mathematical model. Through the above optimization method, the optimization results show that the energy consumption after optimization is 5.6% higher than that before optimization, thus improving the energy utilization rate.

[0103] Preferably, considering environmental parameters, i.e., normal temperature or extremely cold or hot weather, and highway or mountain road conditions, the objective function in step S2 is replaced with:

[0104] Q min =min[f(x1,x2,x3,C,T)],

[0105] In the formula, C is the road characteristic parameter and T is the ambient temperature parameter. C and T can be obtained through experimental calibration, which can be understood by those skilled in the art.

[0106] Preferably, the method further includes the following steps:

[0107] S5. Obtain the speed regulation and braking power of the drive motor;

[0108] S6. When it is identified that the speed regulation braking power is less than the difference between the set charging power of the power battery and the power generation power of the fuel cell, the power generation power of the fuel cell remains unchanged during the gear shifting process;

[0109] S7. When it is identified that the speed regulation braking power is greater than the difference between the set charging power of the power battery and the power generation power of the fuel cell, the power generation power of the fuel cell is reduced in advance during the gear shifting process.

[0110] Steps S5 to S7 can prevent gear shifting failures and ensure that the braking power of the drive motor meets the speed regulation requirements during the commissioning phase, thereby achieving the goals of gear shifting safety and comfort.

[0111] Preferably, the method further includes the following steps:

[0112] S0. Identify whether the working status of the brake pedal, fuel cell, power battery, high-voltage distribution box, and drive motor is normal. If the working status of the brake pedal, fuel cell, power battery, high-voltage distribution box, and drive motor is normal, then execute steps S1 to S4. Otherwise, the vehicle controller sends an alarm message to the vehicle display screen.

[0113] Step S0 further enhances shifting safety.

[0114] Compared with the prior art, the shift control method provided in this embodiment has the following advantages:

[0115] 1. Based on the multi-island genetic algorithm, the upshift speed, downshift speed, and throttle opening during upshift and downshift in the shift strategy of fuel cell electric vehicles equipped with AMT are optimized to improve the fuel economy of fuel cell electric vehicles.

[0116] 2. This method can provide a reference for optimizing the AMT shifting strategy of fuel cell electric vehicles, and can be combined with other parameters to further formulate a better AMT shifting strategy.

[0117] 3. The optimized energy consumption was reduced by 5.6% compared to the unoptimized state, thus improving energy utilization.

[0118] 4. It can avoid shifting failures and ensure that the braking power of the drive motor meets the speed regulation requirements during the commissioning stage, thus achieving the purpose of shifting safety and comfort.

[0119] Example 3

[0120] This invention also discloses a fuel cell vehicle control system using the shift control method described in Embodiment 1 or 2. The system includes a fuel cell, a drive motor, an AMT (Automated Manual Transmission), a main reducer, and a power battery, such as... Figure 4 As shown, and the vehicle controller.

[0121] The drive motor's power supply terminal is connected to the output terminals of the fuel cell and the power battery, respectively. Its output terminal is connected to the main reducer via the AMT to control the wheel speed of the fuel cell vehicle. The output terminal of the vehicle controller is connected to the control terminals of the drive motor, AMT, main reducer, fuel cell, and power battery.

[0122] The vehicle controller pre-stores multiple theoretical shift speeds for the AMT (Automated Manual Transmission) system, including upshift and downshift speeds. These are used to acquire the throttle opening, upshift speed, and downshift speed of the AMT shift strategy within the vehicle's powertrain during operation. Furthermore, based on the goal of minimizing fuel consumption per 100 kilometers, the controller performs real-time optimization of the throttle opening, upshift speed, and downshift speed. It also controls the AMT to execute the optimized upshift and downshift speeds for gear shifting, and controls the fuel cell to execute the optimized throttle opening during shifting. Finally, it performs calculations for the vehicle's powertrain system based on the optimized throttle opening, upshift speed, and downshift speed, outputting and displaying the optimized fuel consumption per 100 kilometers.

[0123] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or improvements to the prior art of the embodiments, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A shift control method for a fuel cell electric vehicle, characterized in that, Including the following steps: S1. During vehicle operation, acquire the throttle opening, upshift speed, and downshift speed of the AMT shift strategy in the vehicle power system. S2. Based on the goal of minimizing the vehicle's fuel consumption per 100 kilometers, the throttle opening, upshift speed, and downshift speed are optimized in real time. S3. Control the AMT to perform optimized upshift and downshift speeds for gear shifting, and control the fuel cell to perform optimized throttle opening during gear shifting; S4. Calculate the vehicle's power system based on the optimized throttle opening, upshift speed, and downshift speed, and output and display the optimized fuel consumption per 100 kilometers. In step S2 of the optimization process, the objective function is: Q min =min[f(x1,x2,x3)], In the formula, Q min This represents the vehicle's minimum fuel consumption per 100 kilometers, where x1 is the throttle opening, x2 is the upshift speed, and x3 is the downshift speed. The constraints of the objective function include: g (j) (x) ≥0, j=1,2,3,……,m, x i 1 ≤x i ≤x i u , i=1,2,3, In the formula, j is the index of the current constraint, m is the total number of constraints, and x is the independent variable in the objective function, including x1, x2, and x3; g (j) (x) represents the j-th constraint; x i 1 For the independent variable x i The lower limit value, x i u For the independent variable x i The upper limit.

2. The shift control method for a fuel cell electric vehicle according to claim 1, characterized in that, For upshifting, the constraints of the objective function include: The maximum speed within 30 minutes is greater than 120 km / h; The maximum speed per kilometer is greater than 120 km / h; Acceleration time from 0 to 100 km / h is less than 15 seconds.

3. The shift control method for a fuel cell electric vehicle according to claim 1 or 2, characterized in that, For downshifting, the constraints of the objective function include: The maximum gradient is greater than 30%.

4. The shift control method for a fuel cell electric vehicle according to claim 3, characterized in that, Step S2 further includes: S21. Establish a mathematical relationship model between the vehicle's fuel consumption per 100 kilometers and the throttle opening, upshift speed, and downshift speed of the AMT shift strategy, and determine the coefficients in the above mathematical relationship model through actual measurement data. S22. Based on the objective of minimizing the vehicle's fuel consumption per 100 kilometers, the objective function is optimized using a multi-island genetic algorithm to determine the optimized throttle opening, upshift speed, and downshift speed.

5. The shift control method for a fuel cell electric vehicle according to claim 4, characterized in that, Step S22 further includes: S221. Set the parameters in the multi-island genetic algorithm, including population size, generation number, number of islands, migration probability, and migration interval; S222. Based on the goal of minimizing the vehicle's fuel consumption per 100 kilometers, the objective function is optimized by setting the above parameters using a multi-island genetic algorithm to generate new throttle opening, upshift speed, and downshift speed as a new population. S223. Determine the fitness value of the new population, as well as the fuel consumption per 100 kilometers of the vehicle corresponding to the new throttle opening, upshift speed, and downshift speed. S224. Determine whether the fitness value of the new population and the fuel consumption per 100 kilometers of the vehicle meet the set optimization termination conditions. If yes, proceed to step S225; otherwise, return to step S221 to reset the parameters in the multi-island genetic algorithm and optimize the objective function again. S225. End the optimization process and use the new throttle opening, upshift speed, and downshift speed obtained in step S222 as the optimized throttle opening, upshift speed, and downshift speed output.

6. The shift control method for a fuel cell electric vehicle according to claim 1, characterized in that, The objective function in step S2 is replaced with: Q min =min[f(x1,x2,x3,C,T)], In the formula, C is the road characteristic parameter and T is the ambient temperature parameter.

7. The shift control method for a fuel cell electric vehicle according to any one of claims 1, 2, 4, 5, and 6, characterized in that, It also includes the following steps: S5. Obtain the speed regulation and braking power of the drive motor; S6. When it is identified that the speed regulation braking power is less than the difference between the set charging power of the power battery and the power generation power of the fuel cell, the power generation power of the fuel cell remains unchanged during the gear shifting process; S7. When it is identified that the speed regulation braking power is greater than the difference between the set charging power of the power battery and the power generation power of the fuel cell, the power generation power of the fuel cell is reduced in advance during the gear shifting process.

8. The shift control method for a fuel cell electric vehicle according to any one of claims 1, 2, 4, 5, and 6, characterized in that, It also includes the following steps: S0. Identify whether the working status of the brake pedal, fuel cell, power battery, high-voltage distribution box, and drive motor is normal. If the working status of the brake pedal, fuel cell, power battery, high-voltage distribution box, and drive motor is normal, then execute steps S1 to S4. Otherwise, the vehicle controller sends an alarm message to the vehicle display screen.

9. A fuel cell vehicle control system using the shift control method according to any one of claims 1-8, characterized in that, This includes fuel cells, drive motors, AMT (Automated Manual Transmission), main reducers, power batteries, and vehicle controllers; among which, The power supply terminal of the drive motor is connected to the output terminals of the fuel cell and the power battery, respectively. Its output terminal is connected to the main reducer via the AMT to control the wheel speed of the fuel cell vehicle. The output of the vehicle controller is connected to the control terminals of the drive motor, AMT, main reducer, fuel cell, and power battery; The vehicle controller pre-stores multiple theoretical shift speeds for the AMT (Automated Manual Transmission) system, including upshift and downshift speeds. These are used to acquire the throttle opening, upshift speed, and downshift speed of the AMT shift strategy within the vehicle's powertrain during operation. Furthermore, based on the goal of minimizing fuel consumption per 100 kilometers, the controller performs real-time optimization of the throttle opening, upshift speed, and downshift speed. It also controls the AMT to execute the optimized upshift and downshift speeds for gear shifting, and controls the fuel cell to execute the optimized throttle opening during shifting. Finally, it performs calculations for the vehicle's powertrain system based on the optimized throttle opening, upshift speed, and downshift speed, outputting and displaying the optimized fuel consumption per 100 kilometers.

Images