Composite braking control method, composite braking system and vehicle

Abstract

A composite braking control method, a composite braking system and a vehicle, which relate to the technical field of vehicle braking systems. The composite braking control method comprises: acquiring a braking requirement signal, and calculating a real-time maximum regenerative braking strength and a target braking strength; when the maximum regenerative braking strength is 0, distributing the braking strength of different wheels on the basis of an initial braking strength distribution curve, the slope of the initial braking strength distribution curve being k; when there is a regenerative braking strength, on the basis of the maximum regenerative braking strength and the target braking strength, distributing the hydraulic braking strength and regenerative braking strength of different wheels according to a first braking strength threshold value; and a driving electric motor executing the regenerative braking strength, and a hydraulic braking system outputting the hydraulic braking strength of different wheels.

Description

A composite braking control method, system and vehicle

[0001] Cross-references

[0002] This application refers to Chinese patent application No. 202311507663.8 filed on November 14, 2023, entitled "A composite braking control method, its system, and vehicle", which is incorporated into this application in its entirety by reference. Technical Field

[0003] The present application relates to the technical field of vehicle braking systems, and in particular to a compound braking control method, a system thereof, and a vehicle. Background Art

[0004] In recent years, the use of new energy vehicles has become increasingly widespread. Braking performance is a key performance indicator for vehicles and is directly related to traffic safety. Regenerative braking refers to the process of converting the vehicle's kinetic energy into electrical energy and storing it in the battery during braking by controlling the drive motor to generate electricity. This allows for energy recovery during braking, thereby increasing the vehicle's range. Compound braking is a combination of hydraulic braking and regenerative braking, which coordinate these two processes to meet the vehicle's braking needs. Compound braking must ensure vehicle braking stability while maximizing brake energy recovery. Existing compound braking methods prioritize regenerative braking. When the maximum regenerative braking intensity cannot meet the braking demand, hydraulic braking with equal hydraulic pressure is requested on all four wheels, ensuring that the total braking demand is the sum of the regenerative braking intensity and the four-wheel hydraulic braking intensity. Currently, for single-axle drive vehicles, the hydraulic pressure on all four wheels remains the same, and the vehicle maintains the original hydraulic braking intensity distribution between the front and rear wheels.

[0005] The inventors discovered that the related art suffers from at least the following issues: During compound braking, regenerative braking is added to the existing front and rear hydraulic braking intensity distribution, disrupting the original vehicle's braking intensity distribution. This can easily cause the drive axle wheels to lock, leading to poor braking stability for the entire vehicle. Uneven compound braking distribution can lead to instability in single-axle drive vehicles. When the compound braking intensity exceeds the total braking intensity requirement, it can cause wheel lock in single-axle or dual-axle drive vehicles.

[0006] Summary of the Invention

[0007] An embodiment of the present application provides a compound braking control method, the method comprising: obtaining a braking demand signal, calculating a real-time maximum regenerative braking intensity and calculating a target braking intensity; when the maximum regenerative braking intensity is 0, the braking intensity of different wheels is distributed according to an initial braking intensity distribution curve, the slope of the initial braking intensity distribution curve is k; when there is regenerative braking intensity, according to the maximum regenerative braking intensity and the target braking intensity, the hydraulic braking intensity and regenerative braking intensity of different wheels are distributed according to a first braking intensity threshold, the different wheels including driving wheels and non-driving wheels; when the target braking intensity increases: S201, increasing the regenerative braking intensity of the driving wheel to a first regenerative threshold; S202, increasing the hydraulic braking intensity of the non-driving wheel to a first Hydraulic threshold; S203, according to the first braking intensity threshold, the hydraulic braking intensity of all wheels is increased simultaneously according to the slope k of the initial braking intensity distribution curve; S203 can also include S2031, increasing the regenerative braking intensity and hydraulic braking intensity of the driving wheel, and increasing the hydraulic braking intensity of the non-driving wheel, and the sum of the increased regenerative braking intensity and hydraulic braking intensity of the driving wheel is the same as the increased hydraulic braking intensity of the non-driving wheel; S2032, when the regenerative braking intensity of the driving wheel increases to the real-time maximum regenerative braking intensity, according to the first braking intensity threshold, the hydraulic braking intensity of all wheels is increased simultaneously according to the slope k of the initial braking intensity distribution curve; the regenerative braking intensity is executed by the driving motor, and the hydraulic braking intensity of different wheels is output through the hydraulic braking system.

[0008] The calculating of the real-time maximum regenerative braking intensity includes obtaining the current state of the driving motor, the state of the accumulator, and the state of the vehicle to determine the real-time maximum regenerative braking intensity.

[0009] The calculating of the target braking intensity includes obtaining a current brake pedal displacement signal to determine the target braking intensity.

[0010] The braking intensity of the driving wheels includes regenerative braking intensity and / or hydraulic braking intensity, and the braking intensity of the non-driving wheels is hydraulic braking intensity.

[0011] Among them, the first hydraulic threshold is the difference between the product of the braking intensity of the driving wheel and the slope k of the initial braking intensity distribution curve minus the first braking intensity threshold. The first regeneration threshold is a fixed value preset according to the braking intensity and the maximum regenerative braking intensity. The first braking intensity threshold is a preset value.

[0012] The first regeneration threshold is set to be smaller than the real-time maximum regenerative braking intensity.

[0013] When the hydraulic braking intensity of the non-driving wheel is increased, the solenoid valve connected to the driving wheel in the hydraulic braking system is closed, the solenoid valve connected to the non-driving wheel is opened, and the corresponding braking hydraulic pressure is generated in the non-driving wheel.

[0014] Among them, when the hydraulic braking intensity of all wheels is increased simultaneously according to the slope k of the initial braking intensity distribution curve based on the first braking intensity threshold, when the braking hydraulic pressure of the driving wheel is different from that of the non-driving wheel, the solenoid valve of the hydraulic braking system is opened to generate a corresponding braking hydraulic pressure in the non-driving wheel; at the same time, the driving current of the solenoid valve of the driving wheel is adjusted to generate a corresponding braking hydraulic pressure in the driving wheel; and the braking hydraulic pressure of the driving wheel and the non-driving wheel are adjusted to be the same.

[0015] Among them, when the hydraulic braking intensity of all wheels is increased simultaneously according to the slope k of the initial braking intensity distribution curve based on the first braking intensity threshold, when the braking hydraulic pressure of the driving wheel and the non-driving wheel is the same, the solenoid valve of the hydraulic braking system is opened, and corresponding braking hydraulic pressure is generated in the driving wheel and the non-driving wheel.

[0016] Among them, when the target braking intensity is reduced, it may include S301, according to the first braking intensity threshold, proportionally reducing the regenerative braking intensity of the driving wheels and the hydraulic braking intensity of the non-driving wheels at the same time until the regenerative braking intensity reaches the second regenerative threshold; S302, according to the first braking intensity threshold, reducing the hydraulic braking intensity of all wheels at the same time according to the slope k of the initial braking intensity distribution curve; S303, reducing the remaining regenerative braking intensity of the driving wheels.

[0017] The second regeneration threshold is set to be smaller than the real-time maximum regenerative braking intensity.

[0018] In step S301 , the reduced hydraulic braking intensity of the non-driving wheels is k times the reduced regenerative braking intensity of the driving wheels.

[0019] When the hydraulic braking intensity of the non-driving wheel is reduced, the solenoid valve connected to the driving wheel in the hydraulic braking system is closed, and the braking hydraulic pressure of the driving wheel remains unchanged.

[0020] When the hydraulic braking intensity of the non-driving wheel is reduced, the solenoid valve connected to the non-driving wheel is opened, and a corresponding braking hydraulic pressure is generated in the non-driving wheel.

[0021] When the hydraulic braking intensity of all wheels is reduced simultaneously according to the slope k of the initial braking intensity distribution curve based on the first braking intensity threshold, all the solenoid valves of the hydraulic braking system are opened, and corresponding braking hydraulic pressure is generated in the driving wheels and the non-driving wheels.

[0022] Among them, when the real-time maximum regenerative braking intensity is reduced to less than the current regenerative braking intensity, the current regenerative braking intensity is reduced to the real-time maximum regenerative braking intensity, and the hydraulic braking intensity of the driving wheel is increased, and the increase value of the hydraulic braking intensity is the same as the decrease value of the regenerative braking intensity.

[0023] Wherein, the driving current of the solenoid valve connected to the driving wheel in the hydraulic braking system is adjusted to control the braking hydraulic pressure of the driving wheel to correspond to the hydraulic braking intensity.

[0024] An embodiment of the present application also provides a compound braking system, which may include at least one drive motor connected to the wheel, for realizing the conversion between the vehicle's kinetic energy and electrical energy, and generating regenerative braking intensity at the wheel; at least one accumulator, for storing the electrical energy; at least one hydraulic braking system, for generating hydraulic braking intensity, generating the same and / or different braking hydraulic pressure in each wheel brake; and at least one electronic control unit, for compound braking control, for distributing the regenerative braking intensity and the hydraulic braking intensity in each wheel brake.

[0025] Among them, the hydraulic braking system may include: at least one piston cylinder, in which a piston is arranged and filled with brake fluid, and the piston cylinder is hydraulically connected to the wheel brake; at least one motor, which is used to drive the piston to move and push the brake fluid into the wheel brake to establish brake hydraulic pressure in the wheel brake; at least one transmission mechanism, in which the motor, the transmission mechanism and the piston are mechanically connected in sequence, and the transmission mechanism is used to transmit the rotation of the motor to the piston.

[0026] The hydraulic brake system further includes a solenoid valve. The piston cylinder, the solenoid valve and the wheel brake are connected in series. By adjusting the control current of the solenoid valve, the brake hydraulic pressure of the wheel brake connected to the solenoid valve is adjusted.

[0027] The drive motor converts battery electrical energy or engine kinetic energy into wheel-end kinetic energy to achieve driving; under the condition of kinetic energy recovery, the drive motor generates negative torque, converts the wheel-end kinetic energy back into electrical energy and stores it in the accumulator.

[0028] An embodiment of the present application also provides a vehicle that applies the compound braking system of the present application or executes the compound braking control method of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] One or more embodiments are exemplarily described by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0030] FIG1 is an exemplary schematic diagram of a compound braking system according to an embodiment of the present application;

[0031] FIG2 is an exemplary flow chart of a compound braking control method according to an embodiment of the present application;

[0032] FIG3 is an exemplary flow chart of a method for controlling compound braking during boosting according to an embodiment of the present application;

[0033] FIG4 is an exemplary schematic diagram of a braking intensity distribution curve during boosting according to an embodiment of the present application;

[0034] FIG5 is an exemplary flow chart of a method for controlling compound braking during decompression according to an embodiment of the present application;

[0035] FIG. 6 is an exemplary schematic diagram of a braking intensity distribution curve during decompression according to an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of this application more clear, some embodiments of this application are further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain this application and are not used to limit this application.

[0037] Some embodiments of the present application relate to a compound braking system, as shown in FIG1 . The compound braking system may include at least one drive motor (Motor), which is connected to a wheel and is used to convert the vehicle's kinetic energy into electrical energy and generate regenerative braking intensity at the wheel; at least one accumulator (Battery), which is used to store the electrical energy; at least one hydraulic braking system, which is used to generate hydraulic braking intensity, generating the same and / or different brake hydraulic pressures in each wheel brake; and at least one electronic control unit (ECU) for compound braking control, which distributes the regenerative braking intensity and the hydraulic braking intensity in each wheel brake, with the brake hydraulic pressures in each wheel brake being the same or different. As an example, the accumulator (Battery) may be an electrochemical accumulator. For another example, the hydraulic braking system may be a wire-controlled electronic hydraulic braking system, or an integrated wire-controlled hydraulic braking system (iEHB).

[0038] In some embodiments, the hydraulic braking system may include at least one piston cylinder, in which a piston is arranged and filled with brake fluid, and the piston cylinder is hydraulically connected to the wheel brake; at least one motor, which is used to drive the piston to move and push the brake fluid into the wheel brake to establish braking hydraulic pressure in the wheel brake; and at least one transmission mechanism, in which the motor, the transmission mechanism and the piston are mechanically connected in sequence, and the transmission mechanism is used to transmit the rotation of the motor to the piston.

[0039] In some embodiments, the hydraulic braking system further includes a solenoid valve, the piston cylinder, the solenoid valve and the wheel brake are connected in series, and the brake hydraulic pressure of the wheel brake connected to the solenoid valve is adjusted by adjusting the control current of the solenoid valve.

[0040] In some embodiments, the drive motor achieves driving by converting battery electrical energy or engine kinetic energy into wheel-end kinetic energy; under kinetic energy recovery conditions, the drive motor generates negative torque, converting the wheel-end kinetic energy back into electrical energy and storing it in an accumulator.

[0041] In some embodiments, the compound braking system can be applied to single-axle drive vehicles or multi-axle drive vehicles. For example, in a single-axle drive scenario, the vehicle's wheels include a drive wheel and a non-drive wheel. The braking strength of the drive wheel includes regenerative braking strength and hydraulic braking strength, while the braking strength of the non-drive wheel is hydraulic braking strength. The compound braking system performs compound braking on the drive wheel using the regenerative braking strength and hydraulic braking strength. For another example, in a multi-axle drive scenario, the vehicle includes multiple drive axles and correspondingly multiple pairs of drive wheels. The compound braking system performs compound braking on the drive wheel using the regenerative braking strength and hydraulic braking strength.

[0042] An embodiment of the present application also provides a compound braking method, which may include: S101, obtaining a braking demand signal and calculating a real-time maximum regenerative braking intensity and a target braking intensity; when the maximum regenerative braking intensity is 0, distributing the braking intensity of different wheels according to an initial braking intensity distribution curve, wherein the slope of the initial braking intensity distribution curve is k, and the different wheels include drive wheels and non-drive wheels; in this case, the braking intensity of the drive wheels only includes the hydraulic braking intensity. In some embodiments, calculating the real-time maximum regenerative braking intensity specifically includes obtaining the current state of the drive motor, the state of the accumulator, and the state of the vehicle to determine the real-time maximum regenerative braking intensity. In some embodiments, calculating the target braking intensity specifically includes obtaining the current brake pedal displacement signal to determine the target braking intensity.

[0043] S102, when there is regenerative braking intensity, the hydraulic braking intensity and regenerative braking intensity of different wheels are allocated according to the maximum regenerative braking intensity and the target braking intensity according to the first braking intensity threshold; when the target braking intensity increases, process 200 (as shown in Figure 2) is executed. In some embodiments, the different wheels include driving wheels and non-driving wheels, the braking intensity of the driving wheels includes regenerative braking intensity and / or hydraulic braking intensity, and the braking intensity of the non-driving wheels is hydraulic braking intensity. As an example, the first braking intensity threshold is a preset value. Figure 2 is an exemplary flow chart of a compound braking control method provided according to some embodiments of the present invention. As shown in Figure 2, the compound braking control method may include:

[0044] S201, increasing the regenerative braking intensity of the driving wheel to a first regenerative threshold; as an example, the first regenerative threshold is a non-fixed value preset according to the braking intensity and the maximum regenerative braking intensity, and the first regenerative threshold is set to be less than the real-time maximum regenerative braking intensity.

[0045] For example, referring to Figure 4, the front wheel is a driving wheel and the rear wheel is a non-driving wheel. When the braking intensity of the front and rear wheels is 0g, Z free / k=0,Z free The current non-driven wheel braking intensity. When regenerative braking is enabled, the front wheel regenerative braking intensity is initially allocated to increase the front wheel braking intensity to the first regenerative threshold (0.3g). The first regenerative threshold can be a fixed value preset based on the braking intensity and the maximum regenerative braking intensity. The first regenerative threshold is set to be less than the maximum regenerative braking intensity. g is the unit of braking intensity.

[0046] S202, increase the hydraulic braking intensity of the non-driving wheel to a first hydraulic threshold; as an example, the first hydraulic threshold is the product of the braking intensity of the driving wheel and the slope k of the initial braking intensity distribution curve minus the difference between the first braking intensity threshold.

[0047] For example, referring to FIG4 , when the front wheel regenerative braking intensity is distributed to increase the front wheel braking intensity to the first regenerative threshold (0.3g), the rear wheel hydraulic braking intensity is distributed to increase the rear wheel braking intensity to the first hydraulic threshold (Z drive ×kZ threshold =0.06g), Z drive is the current driving wheel braking strength, Z threshold The first hydraulic threshold is the difference between the product of the real-time driving wheel braking intensity and the slope k of the initial braking intensity distribution curve and the first braking intensity threshold.

[0048] In some embodiments, in step S202, when the hydraulic braking intensity of the non-driven wheel is increased, the solenoid valve connected to the driving wheel in the hydraulic braking system is closed, the solenoid valve connected to the non-driven wheel is opened, and the corresponding braking hydraulic pressure is generated in the non-driven wheel.

[0049] S203 simultaneously increases the hydraulic braking intensity of all wheels according to a first braking intensity threshold and the slope k of the initial braking intensity distribution curve. For example, the first braking intensity threshold is a preset value. When the target braking intensity increases, the first braking intensity threshold is set as a buffer zone to prevent excessive increases in the braking intensity of all wheels. The difference between the corresponding rear wheel braking intensity in the initial braking intensity distribution curve and the actual rear wheel braking intensity in the distribution strategy curve according to this method is the set first braking intensity threshold. S203 may specifically execute S2031 and S2032 (as shown in FIG3 ).

[0050] In some embodiments, in step S203, when the hydraulic braking intensity of all wheels is increased simultaneously according to the slope k of the initial braking intensity distribution curve based on the first braking intensity threshold, when the braking hydraulic pressure of the driving wheel is different from that of the non-driving wheel, the solenoid valve of the hydraulic braking system is opened to generate corresponding braking hydraulic pressure in the non-driving wheel; at the same time, the driving current of the solenoid valve of the driving wheel is adjusted to generate corresponding braking hydraulic pressure in the driving wheel; the braking hydraulic pressure of the driving wheel and the non-driving wheel is adjusted to be the same, the solenoid valve of the hydraulic braking system is opened, and corresponding braking hydraulic pressure is generated in the driving wheel and the non-driving wheel.

[0051] In some embodiments, in step S203, when the hydraulic braking intensity of all wheels is increased simultaneously according to the slope k of the initial braking intensity distribution curve based on the first braking intensity threshold, when the braking hydraulic pressure of the driving wheel and the non-driving wheel is the same, the solenoid valve of the hydraulic braking system is opened, and corresponding braking hydraulic pressure is generated in the driving wheel and the non-driving wheel.

[0052] S103: The regenerative braking intensity is applied via the drive motor, and the hydraulic braking intensity of different wheels is output via the hydraulic braking system. For example, the braking hydraulic pressures of the different wheels may be the same or different. In some embodiments, when the target braking intensity is less than the maximum regenerative braking intensity, only the regenerative braking intensity is applied to the drive wheels; when the braking intensity of the drive wheels reaches a first regenerative threshold, the hydraulic braking intensity is applied to the non-drive wheels. For another example, when the target braking intensity is greater than the maximum regenerative braking intensity, the braking demand of the drive wheels is the sum of the maximum regenerative braking intensity and the hydraulic braking intensity, while the braking demand of the non-drive wheels is the hydraulic braking intensity. The hydraulic braking intensity of the drive wheels and the hydraulic braking intensity of the non-drive wheels may be the same or different. The hydraulic braking intensity is the product of the braking hydraulic pressure and a preset coefficient. The preset coefficients are different for the drive wheels and the non-drive wheels. When the braking hydraulic pressures of the drive wheels and the non-drive wheels are the same, the hydraulic braking intensity of the drive wheels and the non-drive wheels increase or decrease according to an initial braking intensity distribution curve, wherein the slope of the initial braking intensity distribution curve is k.

[0053] Some embodiments of the present application also provide a compound braking control method, as shown in Figure 3, the method may include: S2031, increasing the regenerative braking intensity and hydraulic braking intensity of the driving wheel, increasing the hydraulic braking intensity of the non-driving wheel, and the sum of the increased regenerative braking intensity and hydraulic braking intensity of the driving wheel is the same as the increased hydraulic braking intensity of the non-driving wheel.

[0054] For example, referring to Figure 4 , when the front wheel regenerative braking intensity is increased to a first regenerative threshold (0.3g), and the rear wheel hydraulic braking intensity is allocated to increase the rear wheel braking intensity to a first hydraulic threshold (0.06g), the regenerative braking intensity and hydraulic braking intensity of the drive wheels are increased simultaneously, and the hydraulic braking intensity of the non-drive wheels is increased. The sum of the increased regenerative braking intensity and hydraulic braking intensity of the drive wheels is the same as the increased hydraulic braking intensity of the non-drive wheels. For example, the sum of the regenerative braking intensity and hydraulic braking intensity corresponding to an increase in front wheel braking intensity from 0.3g to 0.4g is the same as the hydraulic braking intensity corresponding to an increase in rear wheel braking intensity from 0.06g to 0.09g.

[0055] S2032: When the regenerative braking intensity of the driving wheel reaches the real-time maximum regenerative braking intensity, the hydraulic braking intensity of all wheels is increased simultaneously according to the first braking intensity threshold and the slope k of the initial braking intensity distribution curve.

[0056] For example, referring to Figure 4, when the front wheel regenerative braking intensity increases to 0.4g and the rear wheel hydraulic braking intensity is allocated to 0.09g, the hydraulic braking intensity of all wheels is increased simultaneously according to the slope k of the initial braking intensity allocation curve based on the first braking intensity threshold. For example, when the front wheel braking intensity increases from 0.4g to 0.6g, the corresponding rear wheel braking intensity in the initial braking intensity allocation curve increases from 0.12g to 0.18g. In this allocation strategy, the actual rear wheel braking intensity increases from 0.09g to 0.15g based on the first braking intensity threshold. The first braking intensity threshold is 0.03g.

[0057] In some embodiments, when the real-time maximum regenerative braking intensity decreases to less than the current regenerative braking intensity, the current regenerative braking intensity is reduced to the real-time maximum regenerative braking intensity, and the hydraulic braking intensity of the drive wheel is increased, with the increase in hydraulic braking intensity being equal to the decrease in regenerative braking intensity. In some embodiments, the driving current of a solenoid valve connected to the drive wheel in the hydraulic braking system is adjusted to control the brake hydraulic pressure of the drive wheel to correspond to the hydraulic braking intensity.

[0058] The composite braking control method during decompression provided by an embodiment of the present application, as shown in FIG5 , may include the following steps: S301 , proportionally reducing the regenerative braking intensity of the drive wheels and the hydraulic braking intensity of the non-drive wheels according to a first braking intensity threshold, until the regenerative braking intensity reaches a second regenerative threshold. The second regenerative threshold is set to be less than the real-time maximum regenerative braking intensity.

[0059] In some embodiments, in S301 , the reduced hydraulic braking intensity of the non-driven wheels is k times the reduced regenerative braking intensity of the driven wheels.

[0060] In some embodiments, in S301, when reducing the hydraulic braking intensity of the non-driven wheel, the solenoid valve connected to the driving wheel in the hydraulic braking system is closed, and the braking hydraulic pressure of the driving wheel remains unchanged. The solenoid valve connected to the non-driven wheel is opened, and the corresponding braking hydraulic pressure is generated in the non-driven wheel.

[0061] For example, FIG6 is an exemplary schematic diagram of a braking intensity distribution curve during decompression provided according to some embodiments of the present invention. As shown in FIG6 , the front wheels are driving wheels and the rear wheels are non-driving wheels. When the front wheel braking intensity is 0.6g and the rear wheel braking intensity is 0.15g, the regenerative braking intensity of the driving wheels and the hydraulic braking intensity of the non-driving wheels are proportionally reduced simultaneously according to the first braking intensity threshold until the regenerative braking intensity reaches the second regeneration threshold. The second regeneration threshold is set to be less than the real-time maximum regenerative braking intensity. For example, if the second regeneration threshold is set to 0.3g, when the front wheel braking intensity is reduced from 0.6g to 0.3g, the corresponding rear wheel braking intensity in the initial braking intensity distribution curve is reduced from 0.18g to 0.09g. In the allocation strategy of this method, the actual rear wheel braking intensity is reduced from 0.15g to 0.06g according to the first braking intensity threshold.

[0062] S302: Based on a first braking intensity threshold, the hydraulic braking intensity of all wheels is simultaneously reduced according to the slope k of the initial braking intensity distribution curve. In some embodiments, in S302, when the hydraulic braking intensity of all wheels is simultaneously reduced according to the slope k of the initial braking intensity distribution curve based on the first braking intensity threshold, the solenoid valve of the hydraulic braking system is opened, and corresponding brake hydraulic pressure is generated in the driven wheels and the non-driven wheels.

[0063] As an example, as shown in Figure 6, when the regenerative braking intensity of the drive wheels reaches the second regeneration threshold, the hydraulic braking intensity of all wheels is reduced simultaneously according to the slope k of the initial braking intensity distribution curve. For example, when the front wheel braking intensity reaches the second regeneration threshold, the hydraulic braking intensity of all wheels is reduced simultaneously according to the slope k of the initial braking intensity distribution curve. When the front wheel braking intensity decreases from 0.3g to 0.1g, the corresponding rear wheel braking intensity in the initial braking intensity distribution curve decreases from 0.09g to 0.03g. In this allocation strategy, the actual rear wheel braking intensity is reduced from 0.06g to 0g based on the first braking intensity threshold.

[0064] S303: Reduce the remaining regenerative braking intensity of the driving wheel. S303: Allocate the regenerative braking intensity to the driving wheel brake via an electronic control unit.

[0065] As an example, as shown in Figure 6, when the braking intensity of the non-driven wheels drops to 0g, the remaining regenerative braking intensity of the driven wheels is reduced. For example, when the braking intensity of the rear wheels drops to 0g, the remaining regenerative braking intensity of the front wheels is reduced, that is, the front wheel braking intensity is reduced from 0.1g to 0g.

[0066] In some embodiments, the compound braking method can be applied to single-axle drive vehicles or dual-axle drive vehicles. For example, in a single-axle drive scenario, the vehicle's wheels include a drive wheel and a non-drive wheel. The braking intensity of the drive wheel includes regenerative braking intensity and hydraulic braking intensity, while the braking intensity of the non-drive wheel is hydraulic braking intensity. The compound braking method is applied to the drive wheel using the regenerative braking intensity and hydraulic braking intensity to perform compound braking. For another example, in a multi-axle drive scenario, the vehicle includes multiple drive axles and correspondingly multiple pairs of drive wheels. The compound braking method is applied to the drive wheels using the regenerative braking intensity and hydraulic braking intensity to perform compound braking.

[0067] In some embodiments, a vehicle of the present application may include a compound braking system employing the present application and implement a compound braking method. The compound braking system includes at least one drive motor connected to a wheel for converting vehicle kinetic energy into electrical energy and generating regenerative braking intensity at the wheel; at least one accumulator for storing the electrical energy; at least one hydraulic braking system for generating hydraulic braking intensity, producing the same or different brake hydraulic pressures within each wheel brake; and at least one electronic control unit for compound braking control, which distributes the regenerative braking intensity and the hydraulic braking intensity within each wheel brake. For example, the brake hydraulic pressures within each wheel brake are the same or different. The drive motor achieves drive by converting battery electrical energy or engine kinetic energy into wheel-end kinetic energy. During kinetic energy recovery, the drive motor generates negative torque, converting wheel-end kinetic energy back into electrical energy, which is stored in the accumulator.

[0068] This application has at least the following beneficial effects:

[0069] The composite braking control method and its system and vehicle of the present application include obtaining a braking demand signal and calculating the real-time maximum regenerative braking intensity and the target braking intensity; when the maximum regenerative braking intensity is 0, the braking intensity of different wheels is distributed according to an initial braking intensity distribution curve, and the slope of the initial braking intensity distribution curve is k; when there is regenerative braking intensity, the hydraulic braking intensity and regenerative braking intensity of different wheels are distributed according to the maximum regenerative braking intensity and the target braking intensity according to a first braking intensity threshold; the regenerative braking intensity is executed by driving a motor, and the hydraulic braking intensity of different wheels is output through a hydraulic braking system, thereby increasing vehicle stability, improving the stability and safety of the vehicle braking process, and improving the driving experience.

[0070] It should be noted that the above description of the compound braking system and compound braking method is for convenience only and does not limit the present invention to the scope of the illustrated embodiments. It is understood that those skilled in the art, based on the principles of the present device, may arbitrarily combine the various structures, or combine the substructures with other structures, and make various modifications and changes in form and detail to the functions of the above-described device and operations, without departing from such principles. For example, the compound braking system may be further applied to multi-axle drive vehicles, etc. Such variations are within the scope of protection of the present invention.

Claims

1. A composite braking control method, wherein: The method comprises: Obtain a braking demand signal, calculate a real-time maximum regenerative braking intensity and a target braking intensity; when the maximum regenerative braking intensity is 0, the braking intensity of different wheels is distributed according to an initial braking intensity distribution curve, and the slope of the initial braking intensity distribution curve is k; When there is regenerative braking intensity, the hydraulic braking intensity and the regenerative braking intensity of different wheels are allocated according to the maximum regenerative braking intensity and the target braking intensity according to the first braking intensity threshold; when the target braking intensity increases: S201, increasing the regenerative braking intensity of the driving wheels to a first regeneration threshold; S202, increasing the hydraulic braking intensity of the non-driving wheels to a first hydraulic threshold; S203, increasing the hydraulic braking intensity of all wheels simultaneously according to the first braking intensity threshold and the slope of the initial braking intensity distribution curve; including: S2031, increasing the regenerative braking intensity and hydraulic braking intensity of the driving wheel, and increasing the hydraulic braking intensity of the non-driving wheel, wherein the sum of the increased regenerative braking intensity and hydraulic braking intensity of the driving wheel is the same as the increased hydraulic braking intensity of the non-driving wheel; S2032, when the regenerative braking intensity of the driving wheel increases to the real-time maximum regenerative braking intensity, the hydraulic braking intensity of all wheels is increased simultaneously according to the first braking intensity threshold and the slope k of the initial braking intensity distribution curve; The regenerative braking intensity is executed by driving the motor, and the hydraulic braking intensity of different wheels is output through the hydraulic braking system.

2. The method according to claim 1, wherein: The calculation of the real-time maximum regenerative braking intensity includes obtaining the current state of the driving motor, the state of the accumulator, and the state of the vehicle to determine the real-time maximum regenerative braking intensity.

3. The method according to claim 1, wherein: The calculating the target braking intensity includes acquiring a current brake pedal displacement signal to determine the target braking intensity.

4. The method according to claim 1, wherein: The braking strength of the driving wheel includes regenerative braking strength and / or hydraulic braking strength, and the braking strength of the non-driving wheel is hydraulic braking strength.

5. The method according to claim 1, wherein: The first hydraulic threshold is the difference between the product of the braking intensity of the driving wheel and the slope k of the initial braking intensity distribution curve and the first braking intensity threshold. The first regeneration threshold is a fixed value preset according to the braking intensity and the maximum regenerative braking intensity. The first braking intensity threshold is a preset value.

6. The method according to claim 5, wherein: The first regeneration threshold is set to be smaller than the real-time maximum regenerative braking intensity.

7. The method according to claim 1, wherein: When the hydraulic braking strength of the non-driving wheel is increased, the solenoid valve connected to the driving wheel in the hydraulic braking system is closed, the solenoid valve connected to the non-driving wheel is opened, and the corresponding braking hydraulic pressure is generated in the non-driving wheel.

8. The method according to claim 1, wherein: When the hydraulic braking intensity of all wheels is increased simultaneously according to the first braking intensity threshold value and the slope k of the initial braking intensity distribution curve, when the braking hydraulic pressure of the driving wheel is different from that of the non-driving wheel, the solenoid valve of the hydraulic braking system is opened to generate the corresponding braking hydraulic pressure in the non-driving wheel; at the same time, the driving current of the solenoid valve of the driving wheel is adjusted to generate the corresponding braking hydraulic pressure in the driving wheel; the braking hydraulic pressure of the driving wheel and the non-driving wheel are adjusted to be the same.

9. The method according to claim 8, wherein: When the hydraulic braking intensity of all wheels is increased simultaneously according to the first braking intensity threshold and the slope k of the initial braking intensity distribution curve, when the braking hydraulic pressure of the driving wheel and the non-driving wheel are the same, the solenoid valve of the hydraulic braking system is opened, and corresponding braking hydraulic pressure is generated in the driving wheel and the non-driving wheel.

10. The method according to claim 1, wherein: When the hydraulic braking intensity of all wheels is increased simultaneously according to the first braking intensity threshold and the slope k of the initial braking intensity distribution curve, when the braking hydraulic pressure of the driving wheel and the non-driving wheel are the same, the solenoid valve of the hydraulic braking system is opened, and corresponding braking hydraulic pressure is generated in the driving wheel and the non-driving wheel.

11. The method according to claim 1, wherein: When the target braking intensity is reduced, it includes: S301, according to the first braking intensity threshold, proportionally reducing the regenerative braking intensity of the driving wheels and the hydraulic braking intensity of the non-driving wheels simultaneously until the regenerative braking intensity reaches a second regenerative threshold; S302, according to the first braking intensity threshold, reducing the hydraulic braking intensity of all wheels at the same time according to the slope k of the initial braking intensity distribution curve; S303, reducing the remaining regenerative braking intensity of the driving wheel.

12. The method according to claim 11, wherein: The second regeneration threshold is set to be smaller than the real-time maximum regenerative braking intensity.

13. The method according to claim 11, wherein: In S301 , the reduced non-driving wheel hydraulic braking intensity is k times the reduced driving wheel regenerative braking intensity.

14. The method according to claim 11, wherein: When the hydraulic braking intensity of the non-driving wheel is reduced, the solenoid valve connected to the driving wheel in the hydraulic braking system is closed, and the braking hydraulic pressure of the driving wheel remains unchanged.

15. The method according to claim 14, wherein: When the hydraulic braking intensity of the non-driving wheel is reduced, the solenoid valve connected to the non-driving wheel is opened, and the corresponding braking hydraulic pressure is generated in the non-driving wheel.

16. The method according to claim 15, wherein: When the hydraulic braking intensity of all wheels is reduced simultaneously according to the first braking intensity threshold and the slope k of the initial braking intensity distribution curve, the solenoid valve of the hydraulic braking system is opened, and corresponding braking hydraulic pressure is generated in the driving wheel and the non-driving wheel.

17. The method according to any one of claims 1 to 16, wherein: When the real-time maximum regenerative braking intensity is reduced and is less than the current regenerative braking intensity, the current regenerative braking intensity is reduced to the real-time maximum regenerative braking intensity, and the hydraulic braking intensity of the drive wheel is increased, and the increase value of the hydraulic braking intensity is the same as the decrease value of the regenerative braking intensity.

18. The method according to claim 17, wherein: The driving current of the solenoid valve connected to the driving wheel in the hydraulic braking system is adjusted to control the braking hydraulic pressure of the driving wheel to correspond to the required hydraulic braking intensity.

19. A composite brake system, using the method according to any one of claims 1 to 18, wherein: include: at least one drive motor connected to the wheels for converting kinetic energy of the vehicle into electrical energy and generating regenerative braking intensity at the wheels; at least one accumulator, the accumulator being used to store the electrical energy; at least one hydraulic brake system, the hydraulic brake system being used to generate hydraulic braking intensity and to generate the same and / or different brake hydraulic pressure in each wheel brake; At least one electronic control unit is configured to control a compound braking operation, wherein the compound braking operation distributes the regenerative braking intensity and the hydraulic braking intensity in each wheel brake.

20. The system of claim 19, wherein: The hydraulic brake system comprises: at least one piston cylinder, in which a piston is arranged and filled with brake fluid, and the piston cylinder is hydraulically connected to the wheel brake; at least one motor, the motor being used to drive the piston to move, pushing the brake fluid into the wheel brake to establish brake hydraulic pressure in the wheel brake; At least one transmission mechanism, the motor, the transmission mechanism and the piston are mechanically connected in sequence, and the transmission mechanism is used to transmit the rotation of the motor to the piston.

21. The system of claim 20, wherein: The hydraulic brake system further comprises a solenoid valve. The piston cylinder, the solenoid valve and the wheel brake are connected in series. The brake hydraulic pressure of the wheel brake connected to the solenoid valve is adjusted by adjusting the control current of the solenoid valve.

22. The system of claim 19, wherein: The drive motor converts battery electrical energy or engine kinetic energy into wheel-end kinetic energy to achieve driving; under the condition of kinetic energy recovery, the drive motor generates negative torque to convert the wheel-end kinetic energy back into electrical energy and store it in the accumulator.

23. A vehicle, wherein: Execute the composite braking method described in any one of claims 1 to 18.

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