Coordinated regenerative braking system and method applied to fuel cell vehicle

Abstract

The invention provides a coordinated regenerative braking system and method applied to a fuel cell vehicle, and the system comprises a brake pedal which is used for transmitting a brake signal to a brake controller when being stepped down; the braking controller is used for calculating the deceleration required by the vehicle, the braking torque T which is equal to m * a * r and is required by the vehicle, the distribution electric feedback braking torque T1 and the supplementary distribution air pressure braking torque T2, so that T1 + T2 is equal to T; the driving motor is used for generating negative torque, providing braking force, generating reverse current to charge the high-voltage battery and converting part of kinetic energy of the vehicle into chemical energy to be stored in the high-voltage battery; and the high-voltage battery is used for converting part of kinetic energy of the vehicle into chemical energy for storage through the driving motor. The technical scheme is used for solving the technical problems that in the prior art, the vehicle endurance mileage increasing degree is limited, obvious jerking feeling can occur in supplementary air braking, and the rushing phenomenon occurs in the speed reduction process.

Description

Technical Field

[0001] The present application relates to the field of energy-saving technology for fuel cell vehicles, and in particular to a coordinated regenerative braking system and method for fuel cell vehicles. Background Art

[0002] With the acceleration of global industrialization, greenhouse gas emissions have increased dramatically, leading to a series of serious environmental problems, such as global warming and frequent extreme weather events. These phenomena not only destroy the ecological balance, reduce biodiversity, but also threaten the sustainable use of natural resources. Extreme weather events such as high temperatures, droughts, and floods caused by climate change have had a profound impact on human health and socio-economic development. Against this background, energy conservation and emission reduction have become the focus of global attention. Traditional vehicles use ABS braking systems (anti-lock braking systems, Antilock Brake System, is an advanced automobile safety control system. Its main function is to automatically control the braking force of the brakes when the car brakes to prevent the wheels from being completely locked, thereby maintaining the ability of the wheels to rotate during braking) and EBS systems (electronic brake control systems, is an electronic control system that completely uses electronically controlled air brakes to improve braking comfort and safety. The system adds a brake management function to the original ABS function, and many brake assist systems can be expanded on the EBS electronic control system). Braking energy recovery uses parallel or series braking energy recovery. Such as Figure 1 As shown in FIG. 1 , the parallel type braking energy recovery braking system cannot completely recover the vehicle's kinetic energy, but can only recover part of the energy, and the extent to which the vehicle's cruising range is increased is limited; Figure 2 As shown, although the series-type braking energy recovery braking system can recover more vehicle kinetic energy, the electric feedback torque is too large. When the ABS is activated, the electric brake is withdrawn and the supplementary air pressure brake will cause an obvious jerk. Due to the characteristics of electric brakes, when the vehicle speed is low, the electric feedback braking torque will become smaller or even zero, and the deceleration will also decrease accordingly, causing the vehicle to jerk. Summary of the invention

[0003] In view of this, the present invention provides a coordinated regenerative braking system and method for fuel cell vehicles to solve technical problems such as the limited degree of increasing vehicle cruising range in the prior art, obvious jerkiness when supplementing air pressure braking, and jerking during deceleration.

[0004] The present invention provides a coordinated regenerative braking system for a fuel cell vehicle, the system comprising: a brake pedal, for sending a braking signal to a brake controller when being stepped on, the braking signal comprising a brake pedal opening; a brake controller, connected to the brake pedal, for calculating a required deceleration of the vehicle according to the brake signal, and then calculating a required braking torque T=m*a*r of the vehicle according to the deceleration, firstly allocating an electric feedback braking torque T1 according to the recovery capacity of a drive motor, and then supplementing and allocating a pneumatic braking torque T2, so that T1+T2=T, wherein r is a tire rolling radius, m is a current mass of the vehicle, and a is a required deceleration of the vehicle; a drive motor, connected to the brake pedal and the brake controller, for generating a negative torque under an electric braking condition, providing a braking force, and generating a reverse current to charge a high-voltage battery, so as to convert part of the kinetic energy of the vehicle into chemical energy and store it in the high-voltage battery for the next vehicle drive; and a high-voltage battery, connected to the drive motor, for converting part of the kinetic energy of the vehicle into chemical energy for storage through the drive motor, thereby realizing energy recovery.

[0005] Furthermore, the brake controller is also used to stop distributing the electric feedback braking force and the pneumatic braking force when the vehicle stops or the brake pedal is released.

[0006] Furthermore, the brake controller is also used to adjust the pneumatic braking torque T2 accordingly when the electric feedback braking torque T1 changes, so that T1+T2=T.

[0007] Furthermore, the control method of the brake controller is that when the opening and closing angle of the brake pedal is A∈[0, θ1], the vehicle deceleration a=0; when the opening and closing angle of the brake pedal is A∈(θ1, θ2], the vehicle deceleration a=β1A+β2, wherein β1 and β2 are constants; when the opening and closing angle of the brake pedal is A∈(θ2, θ3], the vehicle deceleration is a=β3A+β4, wherein β3 and β4 are constants; when the opening and closing angle of the brake pedal is A∈(θ3, 100], the vehicle deceleration is a=β0m / s2, wherein β0 is a constant.

[0008] The present invention also provides a method for a coordinated regenerative braking system applied to a fuel cell vehicle, the method comprising: step 1, when the brake pedal is pressed, sending a braking signal to a brake controller, the braking signal comprising a brake pedal opening; step 2, the brake controller calculating the required deceleration of the vehicle according to the brake pedal opening; step 3, the brake controller calculating the required braking torque T=m*a*r of the vehicle according to the deceleration, wherein r is the tire rolling radius, m is the current mass of the vehicle, and a is the required deceleration of the vehicle; step 4, the brake controller first allocates the electric feedback braking torque T1 according to the recovery capacity of the drive motor, and then supplements the allocation of the pneumatic braking torque T2, so that T1+T2=T; step 5, during the electric braking process, the drive motor generates a negative torque, provides a braking force, and generates a reverse current to charge the high-voltage battery; step 6, during the charging process, the high-voltage battery converts part of the kinetic energy of the vehicle into chemical energy for storage, which is used for the next vehicle drive, thereby achieving energy recovery.

[0009] Furthermore, the method also includes: step 7, when the vehicle stops or the brake pedal is released, the brake controller stops distributing the electric feedback braking force and the pneumatic braking force.

[0010] Furthermore, the step 4 also includes: when the electric feedback braking force F1 changes, the pneumatic braking force F2 is also adjusted accordingly, so that F1+F2=F.

[0011] Further, step 2 includes: step 21, when the opening and closing angle of the brake pedal A∈[0, θ1], the vehicle deceleration a=0; step 22, when the opening and closing angle of the brake pedal A∈(θ1, θ2], the vehicle deceleration a=β1A+β2, wherein β1 and β2 are constants; step 23, when the opening and closing angle of the brake pedal A∈(θ2, θ3], the vehicle deceleration is a=β3A+β4, wherein β3 and β4 are constants; step 24, when the opening and closing angle of the brake pedal A∈(θ3, 100], the vehicle deceleration is a=β0 m / s 2 , where β0 is a constant.

[0012] The present invention provides a coordinated regenerative braking system and method for fuel cell vehicles, which utilizes a kinetic energy recovery adjustment function associated with the braking pedal strength to proportionally distribute electric braking force and air braking force according to the braking strength. Under electric braking conditions, the high-voltage battery and the drive motor cooperate to achieve energy recovery and achieve the purpose of energy conservation and emission reduction. At the same time, with the same battery power, the vehicle has a longer cruising range. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the relationship between the pedal opening and the braking torque of a parallel brake energy recovery system provided by the prior art; Figure 2It is a schematic diagram of the relationship between the pedal opening and the braking torque of a series braking energy recovery system provided by the prior art; Figure 3 It is a schematic diagram of the relationship between vehicle speed, time and torque acceleration of the coordinated regenerative braking system provided by the present invention; Figure 4 It is a schematic diagram of the relationship between the pedal opening and the deceleration of the coordinated regenerative braking system provided by the present invention; Figure 5 The present invention provides a schematic flow chart of a coordinated regenerative braking method for a fuel cell vehicle. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Device Item Example: The present invention provides a coordinated regenerative braking system for a fuel cell vehicle, the system comprising a brake pedal, a brake controller, a drive motor, and a high-voltage battery.

[0016] A brake pedal, used to send a brake signal to a brake controller when being depressed, wherein the brake signal includes a brake pedal opening; The brake controller is connected to the brake pedal and is used to calculate the required deceleration of the vehicle based on the brake signal, and then calculate the required braking torque T=m*a*r of the vehicle based on the deceleration. The electric feedback braking torque T1 is first allocated according to the recovery capacity of the drive motor, and then the pneumatic braking torque T2 is additionally allocated, so that T1+T2=T, wherein r is the rolling radius of the tire, m is the current mass of the vehicle, and a is the required deceleration of the vehicle. The brake controller is also used to stop allocating the electric feedback braking force and the pneumatic braking force when the vehicle stops or the brake pedal is released. The brake controller is also used to adjust the pneumatic braking torque T2 accordingly when the electric feedback braking torque T1 changes, so that T1+T2=T, such as Figure 3 As shown. Figure 4As shown, the control method of the brake controller is that when the opening and closing angle of the brake pedal A∈[0, θ1], the vehicle deceleration a=0; when the opening and closing angle of the brake pedal A∈(θ1, θ2], the vehicle deceleration a=β1A+β2, wherein β1 and β2 are constants; when the opening and closing angle of the brake pedal A∈(θ2, θ3], the vehicle deceleration is a=β3A+β4, wherein β3 and β4 are constants; when the opening and closing angle of the brake pedal A∈(θ3, 100], the vehicle deceleration is a=β0m / s2, wherein β0 is a constant.

[0017] The drive motor is connected to the brake pedal and the brake controller, and is used to generate negative torque under electric braking conditions to provide braking force, and to generate reverse current to charge the high-voltage battery, thereby converting part of the vehicle's kinetic energy into chemical energy and storing it in the high-voltage battery for the next vehicle drive; The high-voltage battery is connected to the drive motor and is used to convert part of the vehicle's kinetic energy into chemical energy for storage through the drive motor, thereby achieving energy recovery.

[0018] The present invention provides a coordinated regenerative braking system for fuel cell vehicles. When the driver's deceleration demand is small, the system mainly uses motor braking to achieve energy recovery; when the driver's deceleration demand is large, the motor braking is insufficient and the vehicle is decelerated, and the system mainly uses air pressure braking to achieve rapid braking. The pedal feel of the two is kept consistent throughout the whole process, so that the driver cannot feel the difference.

[0019] Method Item Example: The present application provides a coordinated regenerative braking method for a fuel cell vehicle, such as Figure 5 As shown, the method steps are as follows.

[0020] Step 1: When the brake pedal is depressed, a brake signal is sent to a brake controller, wherein the brake signal includes a brake pedal opening; Step 2, the brake controller calculates the required deceleration of the vehicle according to the brake pedal opening; like Figure 4 As shown, the specific steps of calculating the required deceleration of the vehicle according to the brake pedal opening are as follows.

[0021] Step 21, when the opening and closing angle of the brake pedal is A∈[0,θ1], the vehicle deceleration a=0; Step 22, when the opening and closing angle of the brake pedal is A∈(θ1, θ2], the vehicle deceleration a=β1A+β2, where β1 and β2 are constants; Step 23, when the opening and closing angle of the brake pedal is A∈(θ2, θ3], the vehicle deceleration is a=β3A+β4, where β3 and β4 are constants; Step 24: When the brake pedal is opened and closed at an angle A∈(θ3, 100], the vehicle deceleration is a=β0 m / s 2 , where β0 is a constant.

[0022] From the above content, it can be seen that θ1, θ2, and θ3 can be pre-adjusted according to actual conditions.

[0023] Step 3, the brake controller calculates the required braking torque T = m*a*r of the vehicle according to the deceleration, where r is the rolling radius of the tire, m is the current mass of the vehicle, and a is the required deceleration of the vehicle; Step 4: The brake controller first distributes the electric feedback braking torque T1 according to the recovery capacity of the drive motor, and then distributes the pneumatic braking torque T2 in addition, so that T1+T2=T; The step 4 also includes: when the electric feedback braking force F1 changes, the pneumatic braking force F2 is also adjusted accordingly, so that F1+F2=F.

[0024] Step 5: During the electric braking process, the drive motor generates negative torque to provide braking force and generates reverse current to charge the high-voltage battery; Step 6: During the charging process, the high-voltage battery converts part of the vehicle's kinetic energy into chemical energy for storage, which is used for the next vehicle drive, thereby achieving energy recovery.

[0025] Step 7: When the vehicle stops or the brake pedal is released, the brake controller stops distributing the electric feedback braking force and the air pressure braking force.

[0026] The present invention provides a coordinated regenerative braking method for fuel cell vehicles. When the driver's deceleration demand is small, the motor braking is mainly used to achieve energy recovery; when the driver's deceleration demand is large, the motor braking is insufficient and the vehicle is decelerated, and the air pressure braking is mainly used to achieve rapid braking. The pedal feel of the two is kept consistent throughout the whole process, so that the driver cannot feel the difference.

[0027] In summary, the embodiments of the present invention provide a coordinated regenerative braking system and method for fuel cell vehicles. The technical solution has a strong energy recovery capability, which can increase the cruising range by 10% to 15%. The deceleration smoothness is good, and the connection between electric braking and pneumatic braking is smooth without any difference. The pedal feel is excellent, and CRBS (brake energy recovery) has the same braking driving feel and pedal feel as the basic power assist.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A coordinated regenerative braking system for a fuel cell vehicle, characterized in that: The system comprises: A brake pedal, used to send a brake signal to a brake controller when being depressed, wherein the brake signal includes a brake pedal opening; The brake controller is connected to the brake pedal and is used to calculate the required deceleration of the vehicle according to the brake signal, and then calculate the required braking torque T=m*a*r of the vehicle according to the deceleration. The electric feedback braking torque T1 is first allocated according to the recovery capacity of the drive motor, and then the pneumatic braking torque T2 is additionally allocated, so that T1+T2=T, where r is the tire rolling radius, m is the current mass of the vehicle, and a is the required deceleration of the vehicle; The drive motor is connected to the brake pedal and the brake controller, and is used to generate negative torque under electric braking conditions to provide braking force, and to generate reverse current to charge the high-voltage battery, thereby converting part of the vehicle's kinetic energy into chemical energy and storing it in the high-voltage battery for the next vehicle drive; The high-voltage battery is connected to the drive motor and is used to convert part of the vehicle's kinetic energy into chemical energy for storage through the drive motor, thereby achieving energy recovery.

2. A coordinated regenerative braking system for a fuel cell vehicle according to claim 1, characterized in that: The brake controller is also used to stop distributing the electric feedback braking force and the pneumatic braking force when the vehicle stops or the brake pedal is released.

3. The coordinated regenerative braking system for a fuel cell vehicle according to claim 1, characterized in that: The brake controller is also used to adjust the pneumatic braking torque T2 accordingly when the electric feedback braking torque T1 changes, so that T1+T2=T.

4. According to claim 1, a coordinated regenerative braking system for a fuel cell vehicle is characterized in that: The control method of the brake controller is that when the opening and closing angle of the brake pedal A∈[0, θ1], the vehicle deceleration a=0; when the opening and closing angle of the brake pedal A∈(θ1, θ2], the vehicle deceleration a=β1A+β2, wherein β1 and β2 are constants; when the opening and closing angle of the brake pedal A∈(θ2, θ3], the vehicle deceleration is a=β3A+β4, wherein β3 and β4 are constants; when the opening and closing angle of the brake pedal A∈(θ3, 100], the vehicle deceleration is a=β0m / s 2 , where β0 is a constant.

5. A method for using the coordinated regenerative braking system for a fuel cell vehicle according to claims 1-4, characterized in that: The method comprises: Step 1, when the brake pedal is stepped on, a brake signal is sent to a brake controller, wherein the brake signal includes a brake pedal opening; Step 2, the brake controller calculates the required deceleration of the vehicle according to the brake pedal opening; Step 3, the brake controller calculates the required braking torque T = m*a*r of the vehicle according to the deceleration, where r is the rolling radius of the tire, m is the current mass of the vehicle, and a is the required deceleration of the vehicle; Step 4: The brake controller first distributes the electric feedback braking torque T1 according to the recovery capacity of the drive motor, and then distributes the pneumatic braking torque T2 in addition, so that T1+T2=T; Step 5: During the electric braking process, the drive motor generates negative torque to provide braking force and generates reverse current to charge the high-voltage battery; Step 6: During the charging process, the high-voltage battery converts part of the vehicle's kinetic energy into chemical energy for storage, which is used for the next vehicle drive, thereby achieving energy recovery.

6. A coordinated regenerative braking method for a fuel cell vehicle according to claim 5, characterized in that: The method further comprises: Step 7: When the vehicle stops or the brake pedal is released, the brake controller stops distributing the electric feedback braking force and the air pressure braking force.

7. A coordinated regenerative braking method for a fuel cell vehicle according to claim 5, characterized in that: The step 4 also includes: when the electric feedback braking force F1 changes, the pneumatic braking force F2 is also adjusted accordingly, so that F1+F2=F.

8. A coordinated regenerative braking method for a fuel cell vehicle according to claim 5, characterized in that: The step 2 comprises: Step 21, when the opening and closing angle of the brake pedal is A∈[0,θ1], the vehicle deceleration a=0; Step 22, when the opening and closing angle of the brake pedal is A∈(θ1, θ2], the vehicle deceleration a=β1A+β2, where β1 and β2 are constants; Step 23, when the opening and closing angle of the brake pedal is A∈(θ2, θ3], the vehicle deceleration is a=β3A+β4, where β3 and β4 are constants; Step 24: When the brake pedal is opened and closed at an angle A∈(θ3, 100], the vehicle deceleration is a=β0 m / s 2 , where β0 is a constant.

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