CN117227492B - Composite braking control method and system and vehicle - Google Patents
Composite braking control method and system and vehicle Download PDFInfo
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- CN117227492B CN117227492B CN202311507663.8A CN202311507663A CN117227492B CN 117227492 B CN117227492 B CN 117227492B CN 202311507663 A CN202311507663 A CN 202311507663A CN 117227492 B CN117227492 B CN 117227492B
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention relates to a compound braking control method and system and a vehicle, and relates to the technical field of vehicle braking systems. The compound brake control method comprises the steps of obtaining a brake demand signal, calculating the real-time maximum regenerative brake strength and calculating the target brake strength; 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 a regenerative braking intensity, according to the maximum regenerative braking intensity and the target braking intensity, distributing braking intensity of different wheels according to a first braking intensity threshold value, wherein the different wheels comprise driving wheels and non-driving wheels; the regenerative braking intensity is executed through the driving motor, the hydraulic braking intensity of different wheels is output through the hydraulic braking system, the stability of the vehicle is improved, the stability and the safety of the braking process of the vehicle are improved, and the driving experience is improved.
Description
Technical Field
The invention relates to the technical field of vehicle braking systems, in particular to a compound braking control method and system and a vehicle.
Background
In recent years, new energy automobiles are increasingly widely applied, and the braking performance is one of important performance indexes of the automobiles and directly relates to traffic safety. In the process of running of the electrically driven vehicle, the regenerative braking means that the driving motor is controlled to be in a power generation state, and the kinetic energy of the vehicle is converted into electric energy to be stored in the battery, so that energy recovery is realized in the process of braking the vehicle, and the driving mileage of the electrically driven vehicle is improved. The compound braking refers to the compound process of hydraulic braking and regenerative braking, and the braking requirements of the vehicle are jointly completed through coordination of the hydraulic braking and the regenerative braking. Composite braking is required to ensure braking stability of the vehicle while maximizing braking energy recovery. The existing compound braking method requests regenerative braking preferentially, when the maximum regenerative braking strength cannot meet the braking requirement, hydraulic braking with the same four-wheel hydraulic pressure is requested, and the total braking requirement is ensured to be the sum of the regenerative braking strength and the four-wheel hydraulic braking strength.
Currently, for a braking method of a single-axle driven vehicle, the hydraulic pressures of four wheels are kept consistent, and the original front and rear wheel hydraulic braking strength distribution relation of the whole vehicle is maintained. However, in the composite braking process, regenerative braking intensity is superimposed on the basis of original front and rear wheel hydraulic braking intensity distribution, and the composite braking breaks the braking intensity distribution of the original vehicle, so that the driving shaft wheel is locked easily, and the braking stability of the whole vehicle is poor. When the compound brake is not distributed evenly, instability of the single-axle drive vehicle will result. When the composite braking strength exceeds the total braking strength requirement, the problems of wheel locking of a single-shaft driving or double-shaft driving vehicle and the like are caused.
Therefore, it is desirable to provide a composite brake control method, a system thereof and a vehicle, wherein different wheel brake intensities are distributed according to a first brake intensity threshold value, so that the stability of the vehicle is improved, the stability and safety of the vehicle in the braking process are improved, and the driving experience is improved.
Disclosure of Invention
According to a first aspect of some embodiments of the present invention, there is provided a compound brake control method, which may include obtaining a brake demand signal, calculating a real-time maximum regenerative brake strength, and calculating a target brake strength; 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 the regenerative braking intensity exists, according to the maximum regenerative braking intensity and the target braking intensity, distributing different wheel braking intensities according to a first braking intensity threshold, wherein the different wheels comprise driving wheels and non-driving wheels, distributing hydraulic braking intensity and/or regenerative braking intensity of the driving wheels, and distributing hydraulic braking intensity of the non-driving wheels; when the target braking strength increases: s201, increasing the regenerative braking strength of the driving wheel to a first regenerative threshold; s202, increasing the hydraulic braking strength of the non-driving wheels to a first hydraulic threshold value; the first hydraulic threshold value is a difference value obtained by subtracting the first braking intensity threshold value from a product value 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 value is a preset value; s203, increasing the regenerative braking intensity and the hydraulic braking intensity of the driving wheels according to a first braking intensity threshold value according to an initial braking intensity distribution curve slope k, and increasing the hydraulic braking intensity of the non-driving wheels, wherein the sum of the braking hydraulic pressures corresponding to the increased regenerative braking intensity and the hydraulic braking intensity of the driving wheels is the same as the braking hydraulic pressure increased by the non-driving wheels; when the regenerative braking intensity of the driving wheel is increased to the real-time maximum regenerative braking intensity, simultaneously increasing the hydraulic braking intensity of all the wheels according to the initial braking intensity distribution curve slope k according to the first braking intensity threshold value; the regenerative braking strength is executed by a driving motor, and the hydraulic braking strengths of different wheels are output by a hydraulic braking system.
In some embodiments, the calculating the real-time maximum regenerative braking strength specifically includes obtaining a current vehicle state to determine the real-time maximum regenerative braking strength.
In some embodiments, the calculating the target brake strength specifically includes obtaining a current brake pedal displacement signal to determine the target brake strength.
In some embodiments, the braking intensity of the driving wheels includes a regenerative braking intensity and/or a hydraulic braking intensity, and the braking intensity of the non-driving wheels is a hydraulic braking intensity.
In some embodiments, the first regenerative threshold is a fixed value preset according to the target braking intensity and the maximum regenerative braking intensity.
In some embodiments, the first regenerative threshold is set to be less than the real-time maximum regenerative braking strength.
In some embodiments, when the hydraulic braking strength of the non-driving wheel is increased in S202, a solenoid valve connected to the driving wheel in the hydraulic braking system is closed, a solenoid valve connected to the non-driving wheel is opened, and a corresponding braking hydraulic pressure is generated in the non-driving wheel.
In some embodiments, in S203, when the brake hydraulic pressure of the driving wheel is different from that of the non-driving wheel, opening a solenoid valve of the hydraulic brake system, generating a corresponding brake hydraulic pressure in the non-driving wheel; simultaneously adjusting the driving current of the electromagnetic valve of the driving wheel, and generating corresponding braking hydraulic pressure in the driving wheel; the brake fluid pressure of the driving wheel and the non-driving wheel is adjusted to be the same.
In some embodiments, in S203, when the brake fluid pressure of the driving wheel and the non-driving wheel is the same, a solenoid valve of the hydraulic brake system is opened, and a corresponding brake fluid pressure is generated in the driving wheel and the non-driving wheel.
In some embodiments, when the target braking intensity is reduced, specifically including S301, according to the first braking intensity threshold value, reducing the regenerative braking intensity of the driving wheel and the hydraulic braking intensity of the non-driving wheel proportionally at the same time until the regenerative braking intensity reaches the second regenerative threshold value; s302, according to a first braking intensity threshold value, simultaneously reducing the hydraulic braking intensity of all wheels according to an initial braking intensity distribution curve slope k; s303, reducing the residual regenerative braking strength of the driving wheel.
In some embodiments, the second regeneration threshold is set to be less than the real-time maximum regenerative braking strength.
In some embodiments, in S301, the reduced non-driving wheel hydraulic brake strength is k times the reduced driving wheel regenerative brake strength.
In some embodiments, in S301, when the hydraulic braking strength of the non-driving wheel is reduced, a 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.
In some embodiments, when the hydraulic braking strength of the non-driving wheel is reduced in S301, a solenoid valve connected to the non-driving wheel is opened, and a corresponding braking hydraulic pressure is generated in the non-driving wheel.
In some embodiments, in S302, when the hydraulic brake intensities of all the wheels are simultaneously reduced according to the first brake intensity threshold value by the initial brake intensity distribution curve slope k, all the solenoid valves of the hydraulic brake system are opened, and the corresponding brake hydraulic pressures are generated in the driving wheels and the non-driving wheels.
In some embodiments, when the maximum regenerative braking intensity in real time is obtained to be smaller than the current regenerative braking intensity, the current regenerative braking intensity is reduced to the maximum regenerative braking intensity in real time, and the hydraulic braking intensity of the driving wheel is increased, the increase value of the hydraulic braking intensity is the same as the decrease value of the regenerative braking intensity.
In some embodiments, the driving current of a solenoid valve connected to the driving wheel in the hydraulic brake system is adjusted to control the brake hydraulic pressure of the driving wheel to correspond to the hydraulic brake intensity.
According to a second aspect of some embodiments of the present invention, there is provided a compound brake system, which may include at least one drive motor connected to a wheel for effecting a conversion between kinetic and electrical energy of the vehicle and generating a regenerative braking strength at the wheel; at least one accumulator for storing said electrical energy; at least one hydraulic brake system for generating hydraulic brake strength, generating the same or different brake hydraulic pressures in each wheel brake; at least one electronic control unit for a compound brake control that distributes brake strength within each wheel brake; the different wheels comprise driving wheels and non-driving wheels, the hydraulic braking intensity and/or the regenerative braking intensity of the driving wheels are distributed, and the hydraulic braking intensity of the non-driving wheels is distributed.
In some embodiments, the hydraulic braking system specifically includes: at least one piston cylinder, wherein a piston is arranged in the piston cylinder and is filled with brake fluid, and the piston cylinder is hydraulically connected with the wheel brakes; at least one motor for moving the piston to push the brake fluid into the wheel brake to establish a brake fluid pressure in the wheel brake; and the motor, the transmission mechanism and the piston are sequentially and mechanically connected, and the transmission mechanism is used for transmitting the rotation of the motor to the piston.
In some embodiments, the hydraulic brake system further includes a solenoid valve connected in series with the piston cylinder, the solenoid valve, and the wheel brake, and the brake hydraulic pressure of the wheel brake connected to the solenoid valve is adjusted by adjusting a control current of the solenoid valve.
In some embodiments, the drive motor is configured to drive by converting battery power or engine kinetic energy into wheel end kinetic energy; under the working condition of kinetic energy recovery, the driving motor generates negative torque, the kinetic energy of the wheel end is converted into electric energy again, and the electric energy is stored in the energy accumulator.
According to a third aspect of some embodiments of the present invention there is provided a vehicle, applying the compound brake system of the present application, or performing the compound brake control method of the present application.
Drawings
For a better understanding and to set forth embodiments of the invention, reference will now be made to the description of embodiments taken in conjunction with the accompanying drawings in which like reference numerals identify corresponding parts throughout.
FIG. 1 is an exemplary schematic illustration of a compound brake system provided in accordance with some embodiments of the present invention.
Fig. 2 is an exemplary flow chart of a compound brake control method provided in accordance with some embodiments of the present invention.
Fig. 3 is an exemplary flow chart of a method of compound brake control at boost provided in accordance with some embodiments of the present invention.
FIG. 4 is an exemplary schematic diagram of a brake strength distribution curve at boost provided in accordance with some embodiments of the present invention.
Fig. 5 is an exemplary flow chart of a method of controlling a compound brake at reduced pressure provided in accordance with some embodiments of the present invention.
FIG. 6 is an exemplary schematic diagram of a brake strength distribution curve at reduced pressure provided in accordance with some embodiments of the present invention.
Detailed Description
Embodiments of the invention include various specific details for ease of understanding, but these are to be considered exemplary only. Accordingly, those skilled in the art will appreciate that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions will be omitted herein for brevity and clarity of description.
The terms and phrases used in the following specification and claims are not limited to a literal sense, but rather are only used for the purpose of clearly and consistently understanding the present invention. Thus, it will be appreciated by those skilled in the art that the descriptions of the various embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It is noted that the terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used in this disclosure refers to and encompasses any or all possible combinations of one or more of the associated listed items. The expressions "first", "second", "said first" and "said second" are used for modifying the respective elements irrespective of order or importance, and are used merely for distinguishing one element from another element without limiting the respective elements.
The embodiment of the invention provides a compound braking control method, a compound braking control system and a vehicle. In order to facilitate understanding of the embodiments of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
FIG. 1 is an exemplary schematic illustration of a compound brake system provided in accordance with some embodiments of the present invention. As shown in fig. 1, the compound brake system may include at least one drive Motor (motorr) coupled to the wheels for effecting conversion between kinetic and electrical energy of the vehicle and generating regenerative braking strength at the wheels; at least one accumulator (Battery) for storing said electrical energy; at least one hydraulic brake system for generating hydraulic brake strength, generating the same or different brake hydraulic pressures in each wheel brake; at least one electronic control unit for a compound brake control that distributes the regenerative brake strength and the hydraulic brake strength within each wheel brake, the brake hydraulic pressure within each wheel brake being the same or different. As an example, the accumulator (Battery) may be an electrochemical accumulator. As another example, the hydraulic brake system may be an electro-hydraulic brake-by-wire system, or may be an integrated hydraulic brake-by-wire system (iefb, integrated Electro-Hydraulic Braking System), or the like.
According to some embodiments of the invention, the hydraulic brake system may comprise at least one piston cylinder in which a piston is arranged and which is filled with brake fluid, the piston cylinder being hydraulically connected to the wheel brake; at least one motor for moving the piston to push the brake fluid into the wheel brake to establish a brake fluid pressure in the wheel brake; and the motor, the transmission mechanism and the piston are sequentially and mechanically connected, and the transmission mechanism is used for transmitting the rotation of the motor to the piston.
In some embodiments, the hydraulic brake system further includes a solenoid valve connected in series with the piston cylinder, the solenoid valve, and the wheel brake, and the brake hydraulic pressure of the wheel brake connected to the solenoid valve is adjusted by adjusting a control current of the solenoid valve.
In some embodiments, the drive motor is configured to drive by converting battery power or engine kinetic energy into wheel end kinetic energy; under the working condition of kinetic energy recovery, the driving motor generates negative torque, the kinetic energy of the wheel end is converted into electric energy again, and the electric energy is stored in the energy accumulator.
According to some embodiments of the present application, the compound brake system may be applied to a single axle drive vehicle, or a multi-axle drive vehicle, or the like. As an example, in a single axle driving scenario, a vehicle wheel includes a driving wheel, the braking strength of which includes a regenerative braking strength and a hydraulic braking strength, and a non-driving wheel, the braking strength of which is a hydraulic braking strength, and the compound braking system performs compound braking at the driving wheel by the regenerative braking strength and the hydraulic braking strength. For another example, in a multi-axle drive scenario, a vehicle includes a plurality of drive axles, with a corresponding plurality of pairs of drive wheels, where the compound brake system applies compound braking via regenerative braking strength and hydraulic braking strength.
According to some embodiments of the present application, the compound braking method may include:
s101, acquiring a brake demand signal, calculating real-time maximum regenerative brake strength and calculating target brake strength; 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, and the different wheels comprise driving wheels and non-driving wheels; in this case, the braking strength of the driving wheel includes only the hydraulic braking strength. In some embodiments, the calculating the real-time maximum regenerative braking strength specifically includes obtaining a current driving motor state, an accumulator state, and a vehicle state to determine the real-time maximum regenerative braking strength. In some embodiments, the calculating the target brake strength specifically includes obtaining a current brake pedal displacement signal to determine the target brake strength.
S102, when the regenerative braking intensity exists, distributing the braking intensity of different wheels according to a first braking intensity threshold value according to the maximum regenerative braking intensity and the target braking intensity; the process 200 (shown in fig. 2) is performed when the target brake strength increases. In some embodiments, the different wheels include a drive wheel and a non-drive wheel, the braking strength of the drive wheel including a regenerative braking strength and/or a hydraulic braking strength, the braking strength of the non-drive wheel being a hydraulic braking strength. As an example, the first brake strength threshold value is a preset value. Fig. 2 is an exemplary flow chart of a compound brake control method provided in accordance with some embodiments of the present invention. As shown in fig. 2, the compound brake control method may include:
s201, increasing the regenerative braking strength of the driving wheel to a first regenerative threshold; as an example, the first regenerative threshold value may be a fixed value preset according to the target braking intensity and the maximum regenerative braking intensity, or may be a non-fixed value; the first regeneration threshold is set to be less than the real-time maximum regenerative braking strength.
By way of example, FIG. 4 is an exemplary schematic illustration of a brake strength distribution curve at boost provided in accordance with some embodiments of the present invention, as shown in FIG. 4, with the front wheels being the driven wheels and the rear wheels being the non-driven wheels, Z when the front and rear wheel brake strengths are both 0g free /k＝0g，Z free For the current non-driving wheel brake strength, when there is a regenerative brake strength, the front wheel regenerative brake strength is first assigned to a first regenerative threshold (0.3 g). The first regeneration threshold may be a fixed value preset according to the target braking intensity and the maximum regenerative braking intensity, and the first regeneration threshold is set to be smaller than the maximum regenerative braking intensity. g is the unit of braking strength.
S202, increasing the hydraulic braking strength of the non-driving wheels to a first hydraulic threshold value; as an example, the first hydraulic threshold value is a difference value of a product value of the braking strength of the driving wheel and the initial braking strength distribution curve slope k minus a first braking strength threshold value, which is a preset value.
As an example, as shown in fig. 4, when the front wheel regenerative braking intensity is assigned to the first regenerative threshold value (0.3 g), the rear wheel hydraulic braking intensity is assigned to the first hydraulic threshold value (Z drive ×k-Z threshold ＝0.06g)，Z drixe Z is the current driving wheel braking strength threshold Is a first brake strength threshold. The first hydraulic threshold value is the difference value obtained by subtracting the first braking strength threshold value from the product value of the real-time driving wheel braking strength and the initial braking strength distribution curve slope k.
In some embodiments, when the hydraulic braking strength of the non-driving wheel is increased in S202, a solenoid valve connected to the driving wheel in the hydraulic braking system is closed, a solenoid valve connected to the non-driving wheel is opened, and a corresponding braking hydraulic pressure is generated in the non-driving wheel.
S203, simultaneously increasing the hydraulic braking intensity of all wheels according to the slope k of the initial braking intensity distribution curve according to the first braking intensity threshold value; as an example, the first brake strength threshold value is a preset value, and when the target brake strength increases, the first brake strength threshold value is set as a buffer zone in order to avoid excessive increase of the brake strength of all wheels; the same front wheel braking intensity is based on the corresponding rear wheel braking intensity in the initial braking intensity distribution curve, and the difference value between the same front wheel braking intensity and the corresponding actual rear wheel braking intensity in the distribution strategy curve based on the method is a set first braking intensity threshold value. S203 may specifically execute S2031, S2032 (as shown in fig. 3).
In some embodiments, in S203, when the hydraulic brake intensities of all the wheels are simultaneously increased according to the first brake intensity threshold value according to the initial brake intensity distribution curve slope k, when the brake hydraulic pressures of the driving wheels and the non-driving wheels are different, opening the solenoid valve of the hydraulic brake system, and generating corresponding brake hydraulic pressures in the non-driving wheels; simultaneously adjusting the driving current of the electromagnetic valve of the driving wheel, and generating corresponding braking hydraulic pressure in the driving wheel; and adjusting the brake hydraulic pressures of the driving wheels and the non-driving wheels to be the same, opening an electromagnetic valve of the hydraulic brake system, and generating corresponding brake hydraulic pressures in the driving wheels and the non-driving wheels.
In some embodiments, in S203, when the hydraulic brake pressures of all the wheels are simultaneously increased according to the first brake intensity threshold value according to the initial brake intensity distribution curve slope k, when the brake hydraulic pressures of the driving wheels and the non-driving wheels are the same, solenoid valves of the hydraulic brake system are opened, and corresponding brake hydraulic pressures are generated in the driving wheels and the non-driving wheels.
And S103, executing the regenerative braking strength through a driving motor, and outputting the hydraulic braking strengths of different wheels through a hydraulic braking system. As an example, the brake fluid pressure of the different wheels is the same or different. In some embodiments, only regenerative braking strength is allocated at the drive wheel when the target braking strength is less than the maximum regenerative braking strength; when the braking intensity of the driving wheel reaches a first regeneration threshold value, hydraulic braking intensity is distributed to the non-driving wheel. For another example, when the target braking intensity is greater than the maximum regenerative braking intensity, the braking demand of the driving wheels is the sum of the maximum regenerative braking intensity and the hydraulic braking intensity, and the braking demand of the non-driving wheels is the hydraulic braking intensity; the hydraulic brake strength of the driving wheels may be the same as or different from the hydraulic brake strength of the non-driving wheels. The hydraulic braking strength is the product value of the braking hydraulic pressure and a preset coefficient, the preset coefficients of the driving wheel and the non-driving wheel are different, and when the braking hydraulic pressures of the driving wheel and the non-driving wheel are the same, the hydraulic braking strength of the driving wheel and the non-driving wheel is increased or decreased according to an initial braking strength distribution curve, and the slope of the initial braking strength distribution curve is k.
Fig. 3 is an exemplary flow chart of a method of compound brake control at boost provided in accordance with some embodiments of the present invention. As shown in fig. 3, the method specifically includes:
s2031, increasing the regenerative braking strength and the hydraulic braking strength of the driving wheels, and increasing the hydraulic braking strength of the non-driving wheels, wherein the sum of the braking hydraulic pressures corresponding to the increased regenerative braking strength and the hydraulic braking strength of the driving wheels is the same as the braking hydraulic pressure increased by the non-driving wheels;
as an example, fig. 4 is an exemplary schematic diagram of a brake strength distribution curve at the time of boosting, provided according to some embodiments of the present invention, as shown in fig. 4, when the front wheel regenerative brake strength is increased to a first regenerative threshold value (0.3 g), the rear wheel hydraulic brake strength is distributed to a first hydraulic threshold value (0.06 g), the regenerative brake strength and the hydraulic brake strength of the driving wheels are simultaneously increased, and the hydraulic brake strength of the non-driving wheels is increased, and the sum of the brake hydraulic pressures corresponding to the increased regenerative brake strength and the hydraulic brake strength of the driving wheels is the same as the increased brake hydraulic pressure of the non-driving wheels. For example, the sum of the brake fluid pressures corresponding to the front wheel brake strength increased from 0.3g to 0.4g is the same as the brake fluid pressure corresponding to the rear wheel brake strength increased from 0.06g to 0.09 g.
S2032, when the regenerative braking strength of the drive wheels increases to the real-time maximum regenerative braking strength, simultaneously increasing the hydraulic braking strengths of all the wheels according to the initial braking strength distribution curve slope k according to the first braking strength threshold value.
As an example, as shown in fig. 4, when the front wheel regenerative braking strength is increased to 0.4g and the rear wheel hydraulic braking strength is allocated to 0.09g, the hydraulic braking strengths of all the wheels are simultaneously increased according to the first braking strength threshold value at the initial braking strength allocation curve slope k. For example, when the front wheel brake strength increases from 0.4g to 0.6g, the corresponding rear wheel brake strength increases from 0.12g to 0.18g in the initial brake strength distribution curve; in the present method distribution strategy, the actual rear wheel brake strength is increased from 0.09g to 0.15g according to the first brake strength threshold. The first brake strength threshold value is 0.03g.
In some embodiments, when the maximum regenerative braking intensity in real time is obtained to be smaller than the current regenerative braking intensity, the current regenerative braking intensity is reduced to the maximum regenerative braking intensity in real time, and the hydraulic braking intensity of the driving wheel is increased, the increase value of the hydraulic braking intensity is the same as the decrease value of the regenerative braking intensity. In some embodiments, the driving current of a solenoid valve connected to the driving wheel in the hydraulic brake system is adjusted to control the brake hydraulic pressure of the driving wheel to correspond to the hydraulic brake intensity.
Fig. 5 is an exemplary flow chart of a method of controlling a compound brake at reduced pressure provided in accordance with some embodiments of the present invention. As shown in fig. 5, when the target braking strength is reduced, specifically including:
s301, according to the first braking intensity threshold value, the regenerative braking intensity of the driving wheels and the hydraulic braking intensity of the non-driving wheels are reduced proportionally at the same time until the regenerative braking intensity reaches the second braking threshold value. The second regeneration threshold is set to be less than the real-time maximum regenerative braking strength.
In some embodiments, in S301, the reduced non-driving wheel hydraulic brake strength is k times the reduced driving wheel regenerative brake strength.
In some embodiments, in S301, when the hydraulic braking strength of the non-driving wheel is reduced, a 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. Opening a solenoid valve connected to the non-driving wheel and generating a corresponding brake hydraulic pressure in the non-driving wheel.
By way of example, FIG. 6 is an exemplary schematic diagram of a brake strength distribution curve at reduced pressure provided in accordance with some embodiments of the present invention, as shown in FIG. 6, with front wheels being driven and rear wheels being non-driven, and with front wheel brake strength being 0.6g and rear wheel brake strength being 0.15g, the regenerative brake strength of the drive wheels and the hydraulic brake strength of the non-drive wheels being proportionally reduced in accordance with a first brake strength threshold until the regenerative brake strength reaches a second regenerative threshold. The second regeneration threshold is set to be less than the real-time maximum regenerative braking strength. For example, if the second regeneration threshold is set to 0.3g, when the front wheel brake strength is reduced from 0.6g to 0.3g, the corresponding rear wheel brake strength is reduced from 0.18g to 0.09g in the initial brake strength distribution curve, and in the present method distribution strategy, the actual rear wheel brake strength is reduced from 0.15g to 0.06g according to the first brake strength threshold.
S302, according to the first braking intensity threshold value, 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 brake intensities of all the wheels are simultaneously reduced according to the first brake intensity threshold value by the initial brake intensity distribution curve slope k, solenoid valves of the hydraulic brake system are opened, and corresponding brake hydraulic pressures are generated in the driving wheels and the non-driving wheels.
As an example, as shown in fig. 6, when the regenerative braking strength of the driving wheel reaches the second regenerative threshold value, the hydraulic braking strengths of all the wheels are simultaneously reduced at the initial braking strength distribution curve slope k. For example, when the front wheel brake strength reaches the second regeneration threshold, the hydraulic brake strength of all wheels is reduced simultaneously according to the slope k of the initial brake strength distribution curve, and when the front wheel brake strength is reduced from 0.3g to 0.1g, the corresponding rear wheel brake strength is reduced from 0.09g to 0.03g in the initial brake strength distribution curve, and in the method distribution strategy, the actual rear wheel brake strength is reduced from 0.06g to 0g according to the first brake strength threshold.
S303, reducing the residual regenerative braking strength of the driving wheel. S303 distributes the regenerative braking strength in the driving wheel brake by means of an electronic control unit.
As an example, as shown in fig. 6, when the non-driving wheel braking strength decreases to 0g, the remaining regenerative braking strength of the driving wheel is reduced. For example, when the rear wheel brake strength is reduced to 0g, the remaining regenerative brake strength of the front wheels is reduced, that is, the front wheel brake strength is reduced from 0.1g to 0g.
According to some embodiments of the present application, the compound braking method may be applied to a single-axle drive vehicle, or a dual-axle drive vehicle, or the like. As an example, in a single-axis driving scenario, a vehicle wheel includes a driving wheel, the braking strength of which includes a regenerative braking strength and a hydraulic braking strength, and a non-driving wheel, the braking strength of which is a hydraulic braking strength, and the compound braking method is applied to the driving wheel to compound brake by the regenerative braking strength and the hydraulic braking strength. For another example, in a multi-axle drive scenario, where the vehicle includes a plurality of drive axles, and a corresponding plurality of pairs of drive wheels, the compound brake method is applied to compound brake the drive wheels with regenerative and hydraulic braking strengths.
According to some embodiments of the present application, a vehicle of the present application may include applying a compound braking system of the present application and performing a compound braking method. The compound brake system comprises at least one driving motor connected with wheels for realizing conversion between kinetic energy and electric energy of the vehicle and generating regenerative braking intensity at the wheels; at least one accumulator for storing said electrical energy; at least one hydraulic brake system for generating hydraulic brake strength, generating the same or different brake hydraulic pressures in each wheel brake; at least one electronic control unit for a compound brake control that distributes brake strength within each wheel brake; the different wheels comprise driving wheels and non-driving wheels, the hydraulic braking intensity and/or the regenerative braking intensity of the driving wheels are distributed, and the hydraulic braking intensity of the non-driving wheels is distributed. As an example, the brake fluid pressure in each wheel brake is the same or different. The driving motor converts battery electric energy or engine kinetic energy into wheel end kinetic energy so as to realize driving; under the working condition of kinetic energy recovery, the driving motor generates negative torque, the kinetic energy of the wheel end is converted into electric energy again, and the electric energy is stored in the energy accumulator.
It should be noted that the above description of the compound brake system, the compound brake method, and the like is for convenience of description only, and is not intended to limit the present invention to the scope of the illustrated embodiments. It will be understood by those skilled in the art that various modifications and changes in form and detail of the functions of implementing the above-described apparatus and operations may be made to the individual structures in any combination or constituent sub-structures with other structures without departing from the principles of the present apparatus based on the principles. For example, the compound brake system may be further applied to a multi-axle drive vehicle or the like. Such variations are within the scope of the invention.
In summary, the composite brake control method, the system and the vehicle of the invention comprise the steps of obtaining a brake demand signal, calculating the real-time maximum regenerative brake strength and calculating the target brake strength; when the maximum regenerative braking intensity is 0, the braking intensity of different wheels is distributed according to an initial braking intensity distribution curve, wherein the slope of the initial braking intensity distribution curve is k; when the regenerative braking intensity exists, according to the maximum regenerative braking intensity and the target braking intensity, the hydraulic braking intensity and the regenerative braking intensity of different wheels are distributed according to a first braking intensity threshold value; the regenerative braking intensity is executed through the driving motor, the hydraulic braking intensity of different wheels is output through the hydraulic braking system, the stability of the vehicle is improved, the stability and the safety of the braking process of the vehicle are improved, and the driving experience is improved.
It should be noted that the above-described embodiments are merely examples, and the present invention is not limited to such examples, but various changes may be made.
It should be noted that in this specification the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The above disclosure is illustrative of only some of the preferred embodiments of the present invention and should not be taken as limiting the scope of the invention, as those skilled in the art will recognize that all or part of the structures described above may be implemented and equivalents thereof may be substituted for elements thereof which are shown in the claims below and still fall within the true scope of the present invention.
Claims (23)
1. A compound braking control method is characterized in that:
acquiring a brake demand signal, calculating the real-time maximum regenerative brake strength and calculating the target brake strength; 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 the regenerative braking intensity exists, according to the maximum regenerative braking intensity and the target braking intensity, distributing different wheel braking intensities according to a first braking intensity threshold, wherein the different wheels comprise driving wheels and non-driving wheels, distributing hydraulic braking intensity and/or regenerative braking intensity of the driving wheels, and distributing hydraulic braking intensity of the non-driving wheels; when the target braking strength increases:
s201, increasing the regenerative braking strength of the driving wheel to a first regenerative threshold;
s202, increasing the hydraulic braking strength of the non-driving wheels to a first hydraulic threshold value; the first hydraulic threshold value is a difference value obtained by subtracting the first braking intensity threshold value from a product value 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 value is a preset value;
s203, increasing the regenerative braking intensity and the hydraulic braking intensity of the driving wheels according to a first braking intensity threshold value according to an initial braking intensity distribution curve slope k, and increasing the hydraulic braking intensity of the non-driving wheels, wherein the sum of the braking hydraulic pressures corresponding to the increased regenerative braking intensity and the hydraulic braking intensity of the driving wheels is the same as the braking hydraulic pressure increased by the non-driving wheels; when the regenerative braking intensity of the driving wheel is increased to the real-time maximum regenerative braking intensity, simultaneously increasing the hydraulic braking intensity of all the wheels according to the initial braking intensity distribution curve slope k according to the first braking intensity threshold value;
the regenerative braking strength is executed by a driving motor, and the hydraulic braking strengths of different wheels are output by a hydraulic braking system.
2. The method of claim 1, wherein calculating the real-time maximum regenerative braking strength specifically comprises obtaining a current vehicle state to determine the real-time maximum regenerative braking strength.
3. The method of claim 1, wherein calculating the target brake strength specifically comprises obtaining a current brake pedal displacement signal to determine the target brake strength.
4. The method of claim 1, wherein the braking intensity of the driving wheels comprises regenerative braking intensity and/or hydraulic braking intensity, and the braking intensity of the non-driving wheels is hydraulic braking intensity.
5. The method of claim 1, wherein the first regenerative threshold is a fixed value preset based on the target brake strength and the maximum regenerative brake strength.
6. The method of claim 5, wherein the first regeneration threshold is set to be less than a real-time maximum regenerative braking strength.
7. The method according to claim 1, wherein in S202, when the hydraulic braking strength of the non-driving wheel is increased, a solenoid valve connected to the driving wheel in the hydraulic braking system is closed, a solenoid valve connected to the non-driving wheel is opened, and a corresponding brake hydraulic pressure is generated in the non-driving wheel.
8. The method according to claim 1, characterized in that in S203, when the brake hydraulic pressure of the driving wheel and the non-driving wheel is different, a solenoid valve of the hydraulic brake system is opened, and a corresponding brake hydraulic pressure is generated in the non-driving wheel; simultaneously adjusting the driving current of the electromagnetic valve of the driving wheel, and generating corresponding braking hydraulic pressure in the driving wheel; the brake fluid pressure of the driving wheel and the non-driving wheel is adjusted to be the same.
9. The method according to claim 8, wherein in S203, when the brake hydraulic pressure of the driving wheel and the non-driving wheel is the same, a solenoid valve of the hydraulic brake system is opened, and a corresponding brake hydraulic pressure is generated in the driving wheel and the non-driving wheel.
10. The method according to claim 1, characterized in that in S203, when the brake hydraulic pressure of the driving wheel and the non-driving wheel is the same, a solenoid valve of the hydraulic brake system is opened, and a corresponding brake hydraulic pressure is generated in the driving wheel and the non-driving wheel.
11. The method according to claim 1, characterized in that, when the target braking strength decreases, it comprises in particular:
s301, according to a first braking intensity threshold value, reducing the regenerative braking intensity of the driving wheel and the hydraulic braking intensity of the non-driving wheel proportionally at the same time until the regenerative braking intensity reaches a second regenerative threshold value;
s302, according to a first braking intensity threshold value, simultaneously reducing the hydraulic braking intensity of all wheels according to an initial braking intensity distribution curve slope k;
s303, reducing the residual regenerative braking strength of the driving wheel.
12. The method of claim 11, wherein the second regeneration threshold is set to be less than a real-time maximum regenerative braking strength.
13. The method of claim 11, wherein in S301, the reduced non-driving wheel hydraulic brake strength is k times the reduced driving wheel regenerative brake strength.
14. The method according to claim 11, wherein in S301, when the hydraulic braking strength of the non-driving wheels is reduced, a solenoid valve connected to the driving wheels in the hydraulic braking system is closed, and the braking hydraulic pressure of the driving wheels is maintained.
15. The method according to claim 14, wherein in S301, when the hydraulic braking strength of the non-driving wheel is reduced, a solenoid valve connected to the non-driving wheel is opened, and a corresponding braking hydraulic pressure is generated in the non-driving wheel.
16. The method according to claim 15, wherein in S302, when the hydraulic brake intensities of all the wheels are simultaneously reduced according to the first brake intensity threshold value by the initial brake intensity distribution curve slope k, solenoid valves of the hydraulic brake system are opened, and corresponding brake hydraulic pressures are generated in the driving wheels and the non-driving wheels.
17. The method of any of claims 1-16, wherein when a real-time maximum regenerative braking strength decrease is obtained and is less than a current regenerative braking strength, decreasing the current regenerative braking strength to the real-time maximum regenerative braking strength, and increasing a hydraulic braking strength of the drive wheel, the hydraulic braking strength is increased by the same value as the decrease in regenerative braking strength.
18. The method of claim 17, wherein adjusting the drive current to a solenoid valve in the hydraulic brake system that is coupled to the drive wheel controls the brake fluid pressure to the drive wheel to correspond to a desired hydraulic brake strength.
19. A compound brake system applying the method of any one of claims 1-18, comprising:
at least one drive motor connected to the wheels for effecting conversion between kinetic and electrical energy of the vehicle and generating regenerative braking strength at the wheels;
at least one accumulator for storing said electrical energy;
at least one hydraulic brake system for generating hydraulic brake strength, generating the same or different brake hydraulic pressures in each wheel brake;
at least one electronic control unit for a compound brake control that distributes brake strength within each wheel brake; the different wheels comprise driving wheels and non-driving wheels, the hydraulic braking intensity and/or the regenerative braking intensity of the driving wheels are distributed, and the hydraulic braking intensity of the non-driving wheels is distributed.
20. The system according to claim 19, characterized in that said hydraulic braking system comprises in particular:
at least one piston cylinder, wherein a piston is arranged in the piston cylinder and is filled with brake fluid, and the piston cylinder is hydraulically connected with the wheel brakes;
at least one motor for moving the piston to push the brake fluid into the wheel brake to establish a brake fluid pressure in the wheel brake;
and the motor, the transmission mechanism and the piston are sequentially and mechanically connected, and the transmission mechanism is used for transmitting the rotation of the motor to the piston.
21. The system according to claim 20, wherein: the hydraulic brake system further comprises an electromagnetic valve, wherein the piston cylinder, the electromagnetic valve and the wheel brake are connected in series, and the brake hydraulic pressure of the wheel brake connected with the electromagnetic valve is adjusted by adjusting the control current of the electromagnetic valve.
22. The system according to claim 19, wherein: the driving motor converts battery electric energy or engine kinetic energy into wheel end kinetic energy so as to realize driving; under the working condition of kinetic energy recovery, the driving motor generates negative torque, the kinetic energy of the wheel end is converted into electric energy again, and the electric energy is stored in the energy accumulator.
23. A vehicle, characterized in that: a compound brake control method according to any one of claims 1 to 18.
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| CN202311507663.8A CN117227492B (en) | 2023-11-14 | 2023-11-14 | Composite braking control method and system and vehicle |
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|---|---|---|---|---|
| JPH0993712A (en) * | 1995-09-19 | 1997-04-04 | Hiroshi Shimizu | Method and apparatus for braking electric vehicle |
| JPH0993711A (en) * | 1995-09-19 | 1997-04-04 | Hiroshi Shimizu | Method and apparatus for braking electric automobile |
| JPH1035446A (en) * | 1996-07-25 | 1998-02-10 | Hiroshi Shimizu | Brake system for electric automobile |
| JP2021109566A (en) * | 2020-01-10 | 2021-08-02 | 株式会社アドヴィックス | Brake control device |
| CN115195679A (en) * | 2021-04-06 | 2022-10-18 | 丰田自动车株式会社 | Vehicle brake system |
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2023
- 2023-11-14 CN CN202311507663.8A patent/CN117227492B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0993712A (en) * | 1995-09-19 | 1997-04-04 | Hiroshi Shimizu | Method and apparatus for braking electric vehicle |
| JPH0993711A (en) * | 1995-09-19 | 1997-04-04 | Hiroshi Shimizu | Method and apparatus for braking electric automobile |
| JPH1035446A (en) * | 1996-07-25 | 1998-02-10 | Hiroshi Shimizu | Brake system for electric automobile |
| JP2021109566A (en) * | 2020-01-10 | 2021-08-02 | 株式会社アドヴィックス | Brake control device |
| CN115195679A (en) * | 2021-04-06 | 2022-10-18 | 丰田自动车株式会社 | Vehicle brake system |
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