CN-116557516-B - Gear shifting control method and gear shifting control system for fuel cell electric automobile

CN116557516BCN 116557516 BCN116557516 BCN 116557516BCN-116557516-B

Abstract

The invention provides a gear shifting control method and a gear shifting control system for a fuel cell electric vehicle, belongs to the technical field of fuel cell electric vehicle control, and solves the problem that an AMT control strategy in the prior art cannot effectively save energy and reduce emission. The method comprises the steps of obtaining throttle opening, upshift speed and downshift speed of an AMT gear shifting strategy in a whole vehicle power system in the running process of the vehicle, optimizing the throttle opening, upshift speed and downshift speed in real time based on the lowest hundred kilometer fuel consumption of the vehicle, controlling the AMT to execute the optimized upshift speed and downshift speed to shift gears, controlling a fuel cell to execute the optimized throttle opening during gear shifting, and calculating the whole vehicle power system according to the optimized throttle opening, upshift speed and downshift speed to output and display the optimized hundred kilometer fuel consumption of the vehicle.

Inventors

ZHENG ZHIQIANG
WANG WEIQIANG
LIU RAN
GAO YUNQING
Fang chuan

Assignees

北京亿华通科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20230522

Claims (9)

1. A shift control method of a fuel cell electric vehicle, comprising the steps of: s1, acquiring throttle opening, upshift speed and downshift speed of an AMT gear shifting strategy in a whole vehicle power system in the running process of a vehicle; S2, optimizing the opening degree of a throttle valve, the speed of upshift and the speed of downshift in real time based on the minimum hundred kilometer fuel consumption of the vehicle as a target; S3, controlling the AMT to execute the optimized upshift speed and downshift speed to shift gears, and controlling the fuel cell to execute the optimized throttle opening during shifting gears; S4, calculating a whole vehicle power system according to the optimized throttle opening, the upshift speed and the downshift speed, and outputting and displaying the optimized hundred kilometer fuel consumption of the vehicle; In the optimization process of step S2, the objective function is: Q min =min[f（x 1 ,x 2 ,x 3 )], Wherein Q min is the lowest value of hundred kilometers of fuel consumption of the vehicle, x 1 is the opening degree of a throttle valve, x 2 is the upshift speed, and x 3 is the downshift speed; 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, Wherein j is the sequence number of the current constraint condition, m is the total number of the constraint conditions, x is the independent variable in the objective function, x 1 、x 2 、x 3 ;g (j) (x) is the j constraint condition, x i 1 is the lower limit value of the independent variable x i , and x i u is the upper limit value of the independent variable x i .
2. The shift control method of the fuel cell electric vehicle according to claim 1, wherein the constraint condition of the objective function for upshifting includes: the highest speed of the vehicle is more than 120km/h within 30 min; the highest vehicle speed of 1km is greater than 120km/h; the acceleration time of 0-100 km/h is less than 15s.
3. The shift control method of a fuel cell electric vehicle according to claim 1 or 2, characterized in that the constraint condition of the objective function for a downshift includes: The maximum climbing gradient is more than 30 percent.
4. The shift control method of a fuel cell electric vehicle according to claim 3, characterized in that the step S2 further includes: S21, establishing a mathematical relationship model of hundred kilometers fuel consumption of the vehicle and throttle opening, upshift speed and downshift speed of an AMT gear shifting strategy, and determining coefficients in the mathematical relationship model through measured data; s22, optimizing an objective function through a multi-island genetic algorithm based on the minimum hundred kilometer fuel consumption of the vehicle as a target, and determining the optimized throttle opening, upshift speed and downshift speed.
5. The shift control method of a fuel cell electric vehicle according to claim 4, wherein the step S22 further includes: s221, setting parameters in a multi-island genetic algorithm, wherein the parameters comprise population number, evolution algebra, island number, migration probability and migration interval; S222, optimizing an objective function by a multi-island genetic algorithm after setting the parameters based on the minimum hundred kilometers of fuel consumption of the vehicle as a target, and generating a new throttle opening, an upshift speed and a downshift speed as a new group; S223, determining the fitness value of the new group, and the hundred kilometers of fuel consumption of the vehicle corresponding to the new throttle opening, the upshift speed and the downshift speed; S224, judging whether the fitness value of the new group and the hundred kilometers of fuel consumption of the vehicle meet the set optimization termination condition, if so, executing the step S225, otherwise, returning to the step S221 to reset parameters in the multi-island genetic algorithm, and optimizing the objective function again; S225, finishing the optimization process, and outputting the new throttle opening degree, the upshift speed and the downshift speed obtained in the step S222 as the optimized throttle opening degree, upshift speed and downshift speed.
6. The shift control method of a fuel cell electric vehicle according to claim 1, wherein the objective function in step S2 is replaced with: Q min =min[f（x 1 ,x 2 ,x 3 ,C,T)], wherein, C is a road characteristic parameter, and T is an ambient temperature parameter.
7. The shift control method of the fuel cell electric vehicle according to any one of claims 1,2, 4, 5, 6, characterized by further comprising the steps of: s5, acquiring the speed regulation braking power of the driving motor; S6, when the speed regulation braking power is identified to be smaller than the difference between the set charging power of the power battery and the power generation power of the fuel battery, the power generation power of the fuel battery is kept unchanged in the gear shifting process; S7, when the speed regulation braking power is recognized to be larger than the difference between the set charging power of the power battery and the power generation power of the fuel battery, carrying out load reduction adjustment on the power generation power of the fuel battery in advance in the gear shifting process.
8. The shift control method of the fuel cell electric vehicle according to any one of claims 1,2, 4, 5, 6, characterized by further comprising the steps of: S0. identifying whether the working states of the brake pedal, the fuel cell, the power cell, the high-voltage distribution box and the driving motor are normal, if the working states of the brake pedal, the fuel cell, the power cell, the high-voltage distribution box and the driving motor are normal, executing the steps S1-S4, otherwise, sending alarm information to a vehicle display screen by the whole vehicle controller.
9. A fuel cell vehicle control system using the shift control method according to any one of claims 1 to 8, characterized by comprising a fuel cell, a drive motor, an AMT, a final drive, a power cell, and a vehicle controller, wherein, The power supply end of the driving motor is respectively connected with the output ends of the fuel cell and the power cell, and the output end of the driving motor is connected with the main speed reducer through the AMT to control the wheel rotating speed of the fuel cell vehicle; The output end of the whole vehicle controller is connected with the control ends of the driving motor, the AMT, the main speed reducer, the fuel cell and the power cell; The method comprises the steps of pre-storing a plurality of AMT gear shifting theoretical rotating speeds in a whole vehicle controller, wherein the AMT gear shifting theoretical rotating speeds comprise an upshift speed and a downshift speed, the AMT gear shifting theoretical rotating speeds are used for acquiring throttle opening, the upshift speed and the downshift speed of an AMT gear shifting strategy in a whole vehicle power system in the running process of the vehicle, the throttle opening, the upshift speed and the downshift speed are optimized in real time based on the minimum hundred kilometers of fuel consumption of the vehicle, the AMT is controlled to execute the optimized upshift speed and the downshift speed to shift gears, the fuel cell is controlled to execute the optimized throttle opening during gear shifting, and the operation of the whole vehicle power system is carried out according to the optimized throttle opening, the upshift speed and the downshift speed, and the hundred kilometers of fuel consumption of the optimized vehicle is output and displayed.

Description

Gear shifting control method and gear shifting control system for fuel cell electric automobile Technical Field The invention relates to the technical field of control of fuel cell electric automobiles, in particular to a gear shifting control method and a gear shifting control system of a fuel cell electric automobile. Background In recent years, with the increasing rise of energy crisis and environmental pollution problems, corresponding policies are put out all over the world to promote the transformation development of the traditional automobile industry. The fuel cell electric vehicle is rapidly developed due to the advantages of both the fuel vehicle and the electric vehicle. The fuel cell electric automobile is an automobile which utilizes fuel such as hydrogen and oxygen in the air to generate electric energy through electrochemical reaction under the action of a catalyst and is driven by taking the electric energy as a main power source. The key component of the fuel cell electric automobile, namely an AMT gear shifting strategy, can influence the dynamic property and the economical efficiency of the whole automobile. The AMT (for short, gearbox) is an electric control mechanical automatic transmission on a fuel cell electric automobile, and an electronic control system is additionally arranged on the basis of a traditional dry clutch and a manual gear transmission to modify a manual gear shifting mechanism into an automatic gear shifting mechanism, so that the automatic gear shifting stepped mechanical automatic transmission is realized. Most of the existing AMT gear shifting strategies cannot consider effective energy conservation and emission reduction. For example, in the gear-shifting control method of the gear-box of the fuel cell vehicle disclosed in chinese patent CN2022110899583, by adjusting the power of the engine of the fuel cell in advance, the braking power of the driving motor in the speed-adjusting stage is ensured to meet the speed-adjusting requirement, and the gear-shifting failure can be avoided, but the corresponding gear-shifting rule of the technology can be influenced by the speed-adjusting braking power requirement of the driving motor, so that the gear-shifting moment and the gear-shifting rule are not optimal, and the fuel economy of the whole vehicle may be poor. According to the AMT gear shifting control method disclosed in the China patent CN202310224786.4, gear shifting is carried out based on the actual rotating speed and the target rotating speed of the engine, the temperature and the flow of the engine cooling liquid can be regulated, but the technology does not consider the fuel economy, and meanwhile, the preset temperature threshold value can be disturbed or needs to be continuously regulated, so that the complexity of system control is increased. Disclosure of Invention In view of the above analysis, the embodiment of the invention aims to provide a gear shift control method and a control system thereof for a fuel cell electric vehicle, which are used for solving the problem that an AMT control strategy in the prior art cannot effectively save energy and reduce emission. In one aspect, an embodiment of the present invention provides a gear shift control method for a fuel cell electric vehicle, including the steps of: s1, acquiring throttle opening, upshift speed and downshift speed of an AMT gear shifting strategy in a whole vehicle power system in the running process of a vehicle; S2, optimizing the opening degree of a throttle valve, the speed of upshift and the speed of downshift in real time based on the minimum hundred kilometer fuel consumption of the vehicle as a target; S3, controlling the AMT to execute the optimized upshift speed and downshift speed to shift gears, and controlling the fuel cell to execute the optimized throttle opening during shifting gears; S4, calculating a whole vehicle power system according to the optimized throttle opening, the upshift speed and the downshift speed, and outputting and displaying the optimized hundred kilometer fuel consumption of the vehicle. The technical scheme has the beneficial effects that the method adopts a double-parameter gear shifting control strategy based on the speed and the throttle opening (the throttle valve is arranged at the fuel gas inlet of the electric pile), and has the characteristics of stability, reliability and simplicity in implementation. Optimization of the AMT shift strategy is beneficial to improving economy, power, safety and emissions performance of the vehicle. The correct gear-shifting control strategy can ensure the stable running of the automobile, save oil and reduce emission and improve the driving comfort. Based on a further improvement of the above method, in the optimization process of step S2, the objective function is: Qmin＝min[f(x1,x2,x3)], Wherein Q min is the lowest value of hundred kilometers of fuel consumption of the vehicle, x 1 is the opening degree of a thrott