Braking energy recovery method, system and electric vehicle

Abstract

The present invention discloses a braking energy recovery method, system and electric vehicle, and relates to the technical field of braking energy recovery of electric vehicles. The braking energy recovery method comprises the following steps: step S10, determining the maximum percentage of braking torque that the motor can currently use according to the actual temperature and actual power of the battery; step S20, selecting a preset motor braking and rear axle braking distribution curve according to the maximum percentage of braking torque that the motor can currently use, determining the percentage of the motor's actual braking torque and the rear axle braking air pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and braking with the percentage of the motor's actual braking torque or / and the rear axle braking air pressure. The present invention can reasonably distribute motor braking and rear axle braking, give full play to the motor's braking capacity, and improve the efficiency of motor braking energy recovery.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle braking energy recovery, and in particular to a braking energy recovery method, system and electric vehicle. Background Art

[0002] At present, the anti-lock braking system (ABS) is used to automatically control the braking force of the brakes when the car brakes, so that the wheels are not locked and are in a state of rolling and sliding (slip rate is about 20%), so as to ensure that the adhesion between the wheels and the ground is at the maximum. The commonly used four-channel ABS has four wheel speed sensors, and a brake pressure regulator device is installed in the pipeline leading to the four wheel brake cylinders for independent control.

[0003] In order to improve the energy efficiency of electric vehicles, the existing technology adds an energy recovery function to electric vehicles, that is, directly superimposing a certain amount of motor braking on the basis of ABS system service braking to recover energy. Although a certain amount of energy can be recovered, the recovery efficiency is not high, and the energy efficiency improvement effect of electric vehicles is not obvious. Summary of the invention

[0004] The embodiments of the present invention provide a braking energy recovery method, system and electric vehicle to solve the technical problem of low recovery efficiency in the braking energy recovery process of existing electric vehicles in the related art.

[0005] In a first aspect, a braking energy recovery method is provided, characterized in that it comprises the following steps:

[0006] Determine the maximum percentage of braking torque that the motor can currently use according to the actual temperature and actual power of the battery;

[0007] A preset motor braking and rear axle braking distribution curve is selected according to the maximum percentage of the braking torque currently available to the motor, and the percentage of the actual motor braking torque and the rear axle braking pressure are determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and braking is performed with the percentage of the actual motor braking torque and / or the rear axle braking pressure.

[0008] In some embodiments, the step of selecting a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque currently available for the motor, determining the percentage of the actual motor braking torque and the rear axle braking pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and braking with the percentage of the actual motor braking torque and / or the rear axle braking pressure includes:

[0009] When the maximum percentage of the braking torque currently available for the motor is greater than 0, the percentage of the actual braking torque of the motor and the rear axle brake pressure are determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and the motor is first used for braking until the percentage of the actual braking torque of the motor reaches the maximum percentage of the braking torque currently available for the motor, and then the rear axle and the motor are used together for braking;

[0010] When the maximum percentage of braking torque currently available to the motor is 0, the rear axle brake pressure is determined according to the selected preset motor brake and rear axle brake distribution curve and the actual brake pedal travel, and only the rear axle is used for braking.

[0011] In some embodiments, the step of determining the maximum percentage of the braking torque that the motor can currently use according to the actual temperature and actual power of the battery includes:

[0012] When the actual battery power is not less than the preset battery power or the actual battery temperature is not less than the preset battery temperature, the maximum percentage of the braking torque that the motor can currently use is determined to be a%, and a% is 0;

[0013] When the actual battery power is less than the preset battery power and the actual battery temperature is not less than the preset battery temperature, the maximum percentage of the braking torque currently available for the motor is determined to be b% according to the actual battery temperature, 0<b%≤100%.

[0014] In some embodiments, before the step of determining the maximum percentage of the braking torque currently available for the motor according to the actual temperature and actual power of the battery, the method further comprises:

[0015] The braking torque currently available for the motor is determined based on a preset motor braking torque and speed curve and the current speed of the motor.

[0016] In a second aspect, a braking energy recovery system is provided, comprising: an ABS controller and a motor controller, wherein the motor controller and the ABS controller are electrically connected;

[0017] The motor controller is used to determine the maximum percentage of braking torque that the motor can currently use according to the actual temperature and actual power of the battery;

[0018] The ABS controller is used to select a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque currently available to the motor, determine the percentage of the actual motor braking torque and the rear axle braking pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and brake at the percentage of the actual motor braking torque and / or the rear axle braking pressure.

[0019] In some embodiments, when the maximum percentage of the braking torque currently available for the motor is greater than 0, the ABS controller is used to determine the percentage of the actual braking torque of the motor and the rear axle braking air pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and first use the motor for braking until the percentage of the actual braking torque of the motor reaches the maximum percentage of the braking torque currently available for the motor, and then use the rear axle and the motor together for braking;

[0020] When the maximum percentage of braking torque currently available to the motor is 0, the ABS controller is used to determine the rear axle brake pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual brake pedal travel, and only use the rear axle for braking.

[0021] In some embodiments, when the actual battery power is not less than the preset battery power or the actual battery temperature is not less than the preset battery temperature, the motor controller is used to determine that the maximum percentage of the braking torque that the motor can currently use is a%, and a% is 0;

[0022] When the actual battery power is less than the preset battery power and the actual battery temperature is not less than the preset battery temperature, the motor controller is used to determine the maximum percentage of braking torque currently available for the motor as b% according to the actual battery temperature, 0<b%≤100%.

[0023] In some embodiments, the braking energy recovery system further comprises:

[0024] A stroke sensor is arranged on the brake pedal and is electrically connected to the ABS controller. The stroke sensor is used to collect the stroke of the brake pedal.

[0025] In some embodiments, the braking energy recovery system further comprises:

[0026] A rear axle control valve group, wherein the rear axle control valve group is provided with a first interface, a second interface, a third interface, a fourth interface, a chamber, a first solenoid valve, a second solenoid valve and a third control valve, wherein the first interface is connected to the air storage compartment, the inlet of the second solenoid valve and the chamber, the fourth interface is connected to the foot brake valve and the inlet of the first solenoid valve, the second interface is connected to the outlet of the chamber and the ABS valve, the third interface is connected to the outside world, the outlet of the first solenoid valve is connected to the chamber and the inlet of the third control valve, the outlet of the second solenoid valve is connected to the inlet of the third control valve, and the outlet of the third control valve is connected to the third interface.

[0027] In a third aspect, an electric vehicle is provided, comprising the aforementioned braking energy recovery system.

[0028] The beneficial effects brought about by the technical solution provided by the present invention include:

[0029] The embodiment of the present invention provides a braking energy recovery method, system and electric vehicle, firstly determining the maximum percentage of braking torque currently available for the motor according to the actual temperature and actual power of the battery, then selecting a preset motor braking and rear axle braking distribution curve according to the maximum percentage of braking torque currently available for the motor, determining the percentage of the actual braking torque of the motor and the rear axle braking air pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and braking is performed with the percentage of the actual braking torque of the motor or / and the rear axle braking air pressure. The present invention reasonably distributes motor braking and rear axle braking, gives full play to the braking capacity of the motor, and improves the efficiency of motor braking energy recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A flow chart of a braking energy recovery method provided by an embodiment of the present invention;

[0032] Figure 2 A preset motor braking and rear axle braking distribution curve provided in an embodiment of the present invention;

[0033] Figure 3 Another preset motor braking and rear axle braking distribution curve provided by an embodiment of the present invention;

[0034] Figure 4 Another preset motor braking and rear axle braking distribution curve provided in an embodiment of the present invention;

[0035] Figure 5 A schematic diagram of a braking energy recovery system provided by an embodiment of the present invention;

[0036] Figure 6 A schematic diagram of a foot brake valve provided in an embodiment of the present invention;

[0037] Figure 7 A schematic diagram of a rear axle control valve group provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The embodiment of the present invention provides a braking energy recovery method, which can solve the technical problem of low recovery efficiency in the braking energy recovery process of existing electric vehicles.

[0040] See also Figure 1 As shown, an embodiment of the present invention provides a braking energy recovery method, comprising the following steps:

[0041] Step S10, determining the maximum percentage of the braking torque that the motor can currently use according to the actual temperature and actual power of the battery.

[0042] Specifically, the step of determining the maximum percentage of the braking torque that the motor can currently use according to the actual temperature and actual power of the battery includes:

[0043] When the actual battery power is not less than the preset battery power or the actual battery temperature is not less than the preset battery temperature, the maximum percentage of braking torque that the motor can currently use is determined to be a%, and a% is 0. When the actual battery power is not less than the preset battery power, it means that the battery power is sufficient, and it is not recommended to recharge by braking. When the actual battery temperature is greater than the preset battery temperature, continuing to recharge by braking may bring safety hazards, and it is not recommended to recharge by braking.

[0044] When the actual battery power is less than the preset battery power and the actual battery temperature is less than the preset battery temperature, the maximum percentage of the braking torque that the motor can currently use is determined to be b% according to the actual battery temperature, 0<b%≤100%. When the actual battery power is less than the preset battery power and the actual battery temperature is less than the preset battery temperature, it means that the battery power is insufficient and the battery temperature is appropriate, meeting the requirements of braking recovery charging. At this time, the maximum percentage of the braking torque that the motor can currently use can be determined according to the actual battery temperature. For example, when the actual battery temperature is 50°C, the maximum percentage of the braking torque that the motor can currently use is determined to be 50%; when the actual battery temperature is 40°C, the maximum percentage of the braking torque that the motor can currently use is determined to be 70%; when the actual battery temperature is below 30°C, the maximum percentage of the braking torque that the motor can currently use is determined to be 100%, which can be determined based on multiple test calibrations.

[0045] Step S20, select a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque currently available for the motor, then determine the percentage of the actual motor braking torque and the rear axle braking pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and brake at the percentage of the actual motor braking torque and / or the rear axle braking pressure.

[0046] Specifically, the step of selecting a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque currently available for the motor, and then determining the percentage of the actual motor braking torque and the rear axle braking pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and braking with the percentage of the actual motor braking torque and / or the rear axle braking pressure includes:

[0047] When the maximum percentage of braking torque currently available for use by the motor is greater than 0, the percentage of the motor's actual braking torque and the rear axle braking pressure are determined based on the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal. The motor is first used for braking until the percentage of the motor's actual braking torque reaches the maximum percentage of the motor's currently available braking torque, and then the rear axle and motor are used together for braking.

[0048] When the maximum percentage of braking torque currently available to the motor is 0, the rear axle brake pressure is determined according to the selected preset motor brake and rear axle brake distribution curve and the actual brake pedal travel, and only the rear axle is used for braking.

[0049] For example, see Figure 2 As shown, when the maximum percentage of the braking torque that the motor can currently use is 50%, the percentage of the motor's actual braking torque and the rear axle braking pressure are determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal. The motor is used for braking first. When the actual travel of the brake pedal reaches about 38 mm, the percentage of the motor's actual braking torque reaches 50% of the maximum percentage of the braking torque that the motor can currently use. The rear axle is then involved, and the rear axle and the motor are used together to brake. The motor braking and rear axle braking are reasonably distributed to give full play to the motor's braking capacity, improve the efficiency of motor braking energy recovery, and thereby improve the energy utilization rate of electric vehicles.

[0050] For another example, see Figure 3As shown, when the maximum percentage of braking torque currently available for the motor is 100%, the percentage of the actual braking torque of the motor and the rear axle brake pressure are determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal. The motor is used for braking first. When the actual travel of the brake pedal reaches about 60 mm, the percentage of the actual braking torque of the motor reaches 100%, the maximum percentage of the braking torque currently available for the motor. The rear axle is then involved, and the rear axle and the motor are used together for braking. The motor braking and the rear axle braking are reasonably distributed. At this time, the maximum braking capacity of the motor is exerted, and the braking energy is recovered with the highest efficiency.

[0051] See also Figure 4 As shown, when the maximum percentage of braking torque currently available to the motor is 0, the rear axle brake pressure is determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and only the rear axle is used for braking, and the motor does not participate in braking, that is, when the motor is not suitable for participating in brake energy recovery, the basic braking capacity is guaranteed to be effective.

[0052] The braking energy recovery method in the embodiment of the present invention first determines the maximum percentage of the braking torque that the motor can currently use according to the actual temperature and actual power of the battery, then selects a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque that the motor can currently use, determines the percentage of the motor's actual braking torque and the rear axle braking pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and brakes with the percentage of the motor's actual braking torque or / and the rear axle braking pressure. The present invention reasonably distributes motor braking and rear axle braking, gives full play to the motor's braking capacity, and improves the efficiency of motor braking energy recovery.

[0053] As an optional implementation, in an embodiment of the invention, before the step of determining the maximum percentage of the braking torque currently available for the motor according to the actual temperature and actual power of the battery, the method includes:

[0054] The braking torque currently available for the motor is determined based on the preset motor braking torque and speed curve and the current speed of the motor. Specifically, Figure 4 The preset motor torque and speed curve. When the electric vehicle is running, according to Figure 4 The curve determines the braking torque that the motor can currently use at the current speed of the motor. When braking to recover energy, the actual braking torque of the motor is finally determined for braking based on the percentage of the braking torque that the motor can currently use and the actual braking torque of the motor.

[0055] See also Figure 5 As shown, the embodiment of the present invention also provides a braking energy recovery system, including: an ABS controller and a motor controller. Figure 5 As shown, the ABS braking system generally includes an ABS controller 8, a foot brake valve 1, four ABS valves 5, four brakes 6, four wheel speed sensors 7, a plurality of air storage compartments 10, etc. In the present invention, the ABS controller 8 is electrically connected to the motor controller 9.

[0056] The motor controller is used to determine the maximum percentage of the braking torque that the motor can currently use according to the actual temperature and actual power of the battery.

[0057] Specifically, when the actual battery power is not less than the preset battery power or the actual battery temperature is not less than the preset battery temperature, the motor controller is used to determine that the maximum percentage of braking torque that the motor can currently use is a%, and a% is 0. When the actual battery power is not less than the preset battery power, it means that the battery power is sufficient, and it is not recommended to recharge by braking. When the actual battery temperature is greater than the preset battery temperature, continuing to recharge by braking may bring safety hazards, and it is not recommended to recharge by braking.

[0058] When the actual battery power is less than the preset battery power and the actual battery temperature is not less than the preset battery temperature, the motor controller is used to determine the maximum percentage of the braking torque that the motor can currently use is b% according to the actual battery temperature, 0<b%≤100%. When the actual battery power is less than the preset battery power and the actual battery temperature is less than the preset battery temperature, it means that the battery power is insufficient and the battery temperature is appropriate, meeting the requirements of braking recovery charging. At this time, the maximum percentage of the braking torque that the motor can currently use can be determined according to the actual battery temperature. For example, when the actual temperature of the battery is 50°C, the maximum percentage of the braking torque that the motor can currently use is determined to be 50%; when the actual temperature of the battery is 40°C, the maximum percentage of the braking torque that the motor can currently use is determined to be 70%; when the actual temperature of the battery is below 30°C, the maximum percentage of the braking torque that the motor can currently use is determined to be 100%, which can be determined based on multiple test calibrations.

[0059] The ABS controller is used to select a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque currently available to the motor, determine the percentage of the actual motor braking torque and the rear axle braking pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and brake at the percentage of the actual motor braking torque and / or the rear axle braking pressure.

[0060] Specifically, when the maximum percentage of braking torque currently available for use by the motor is greater than 0, the ABS controller is used to determine the percentage of the motor's actual braking torque and the rear axle braking pressure based on the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and first use the motor for braking until the percentage of the motor's actual braking torque reaches the maximum percentage of the braking torque currently available for use by the motor, and then use the rear axle and the motor together for braking.

[0061] When the maximum percentage of the braking torque currently available to the motor is 0, the ABS controller is used to determine the rear axle brake pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and only use the rear axle for braking. The ABS controller causes the motor controller to exit controlling the motor braking.

[0062] For example, see Figure 2 As shown, when the maximum percentage of the braking torque that the motor can currently use is 50%, the percentage of the motor's actual braking torque and the rear axle brake pressure are determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal. The motor is used for braking first. When the actual travel of the brake pedal reaches about 38 mm, the percentage of the motor's actual braking torque reaches 50% of the maximum percentage of the braking torque that the motor can currently use. The rear axle is then involved, and the rear axle and motor are used together for braking. The motor braking and rear axle braking are reasonably distributed to give full play to the motor's braking capacity and improve the efficiency of motor braking energy recovery.

[0063] For example, see Figure 3 As shown, when the maximum percentage of braking torque currently available for the motor is 100%, the percentage of the actual braking torque of the motor and the rear axle brake pressure are determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal. The motor is used for braking first. When the actual travel of the brake pedal reaches about 60 mm, the percentage of the actual braking torque of the motor reaches 100%, the maximum percentage of the braking torque currently available for the motor. The rear axle is then involved, and the rear axle and the motor are used together for braking. The motor braking and the rear axle braking are reasonably distributed. At this time, the maximum braking capacity of the motor is exerted, and the braking energy is recovered with the highest efficiency.

[0064] See also Figure 4 As shown, when the maximum percentage of braking torque currently available to the motor is 0, the rear axle brake pressure is determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and only the rear axle is used for braking, and the motor does not participate in braking, that is, when the motor is not suitable for participating in brake energy recovery, the basic braking capacity is guaranteed to be effective.

[0065] The braking energy recovery system in the embodiment of the present invention reasonably distributes motor braking and rear axle braking, fully utilizes the motor braking capacity, and improves the efficiency of motor braking energy recovery.

[0066] As an optional implementation, in one embodiment of the invention, the braking energy recovery system further includes: a travel sensor 16, the travel sensor 16 is arranged on the foot brake valve and is electrically connected to the ABS controller, and the travel sensor 16 is used to collect the travel of the brake pedal. Figure 6 As shown, the travel sensor 16 can be integrated inside the foot brake valve 1 to collect the travel of the brake pedal in real time and send the travel data to the ABS controller 8 . Figure 6 The travel sensor 16 in the apparatus can be provided with two circuits to verify the results with each other.

[0067] As an optional implementation, in an embodiment of the invention, see Figure 7 As shown, the braking energy recovery system also includes: a rear axle control valve group 3, the rear axle control valve group is provided with a first interface 31, a second interface 32, a third interface 33, a fourth interface 34, a chamber 35, a first solenoid valve A, a second solenoid valve B and a third control valve C, the rear axle control valve group, the first interface 31 is connected to the air storage compartment 10, the inlet of the second solenoid valve B and the chamber 35, the fourth interface 34 is connected to the foot brake valve 1 and the inlet of the first solenoid valve A, the second interface 32 is connected to the outlet of the chamber 35 and the ABS valve 5, the third interface 33 is connected to the outside, the outlet of the first solenoid valve A is connected to the chamber 35 and the inlet of the third control valve C, the outlet of the second solenoid valve B is connected to the inlet of the third control valve C, and the outlet of the third control valve C is connected to the third interface 33.

[0068] See also Figure 5 and Figure 7 As shown, usually Figure 5The marks 2 and 3 are the front axle relay valve and the rear axle relay valve respectively. The embodiment of the present invention improves the rear axle relay valve into a rear axle control valve group 3. When the brake energy recovery system does not perform brake energy recovery, the first solenoid valve A, the second solenoid valve B and the third control valve C do not operate, and the fourth interface 34 is connected to the chamber 35. When the brake pedal is pressed, the foot brake valve 1 outputs air pressure to the chamber 35, and the air pressure of the second interface 32 is equal to the air pressure corresponding to the chamber 35, thereby ensuring the normal braking function of the whole vehicle. When the air pressure in the chamber 35 is higher than the air pressure in the second interface 32, the first interface 31 is connected to the second interface 32, the second interface 32 is disconnected from the third interface 33, and the compressed air flows from the first interface 31 to the second interface 32; when the air pressure in the chamber 35 is equal to the air pressure in the second interface 32, the first interface 31 is disconnected from the second interface 32, and the second interface 32 is disconnected from the third interface 33; when the air pressure in the chamber 35 is lower than the air pressure in the second interface 32, the first interface 31 is disconnected from the second interface 32, the second interface 32 is connected to the third interface 33, and the compressed air in the second interface 32 flows from the third interface 33 to the atmosphere. When the braking energy recovery system is performing braking energy recovery, the first solenoid valve A is actuated to close the fourth interface 34, and at the same time the second solenoid valve B is actuated, and the second solenoid valve B leads the compressed air to the chamber 35, and the compressed air goes directly from the first interface 31 to the second interface 32. When the air pressure sensor senses that the air pressure reaches the required air pressure, the second solenoid valve B is closed, and the first interface 31 is disconnected from the second interface 32; when the air pressure at the second interface 32 is too high, the third solenoid valve C is actuated, and the air pressure in the chamber 35 and the compressed air at the second interface 32 are discharged from the third interface 33 at the same time. When the air pressure reaches the required pressure, the third control valve C does not actuate.

[0069] The embodiment of the present invention further provides an electric vehicle, comprising the aforementioned braking energy recovery system, wherein the braking energy recovery system comprises: an ABS controller and a motor controller, wherein the motor controller and the ABS controller are electrically connected. The motor controller is used to determine the maximum percentage of the braking torque that the motor can currently use according to the actual temperature and actual power of the battery. The ABS controller is used to select a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque that the motor can currently use, determine the percentage of the actual braking torque of the motor and the rear axle braking pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and brake with the percentage of the actual braking torque of the motor or / and the rear axle braking pressure. The electric vehicle of the present invention reasonably distributes motor braking and rear axle braking, gives full play to the braking capacity of the motor, and improves the efficiency of motor braking energy recovery.

[0070] In the description of the present invention, it should be noted that the terms "upper", "lower", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0071] It should be noted that, in the present invention, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0072] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A braking energy recovery method, characterized in that: The following steps are involved: Determine the maximum percentage of braking torque that the motor can currently use according to the actual temperature and actual power of the battery; Selecting a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque currently available to the motor, determining the percentage of the actual motor braking torque and the rear axle braking air pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and braking at the percentage of the actual motor braking torque and / or the rear axle braking air pressure; The step of determining the maximum percentage of the braking torque currently available to the motor according to the actual temperature and actual power of the battery comprises: When the actual battery power is not less than the preset battery power or the actual battery temperature is not less than the preset battery temperature, the maximum percentage of braking torque that the motor can currently use is determined to be a%, and a% is 0. At this time, re-braking and recharging are not recommended; When the actual battery power is less than the preset battery power and the actual battery temperature is less than the preset battery temperature, the maximum percentage of braking torque that the motor can currently use is determined to be b% based on the actual battery temperature, 0<b%≤100%, and braking recovery charging is recommended at this time; The step of selecting a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque currently available for the motor, determining the percentage of the actual motor braking torque and the rear axle braking pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and braking with the percentage of the actual motor braking torque and / or the rear axle braking pressure includes: When the maximum percentage of the braking torque currently available for the motor is greater than 0, the percentage of the actual braking torque of the motor and the rear axle brake pressure are determined according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and the motor is first used for braking until the percentage of the actual braking torque of the motor reaches the maximum percentage of the braking torque currently available for the motor, and then the rear axle and the motor are used together for braking; When the maximum percentage of braking torque currently available to the motor is 0, the rear axle brake pressure is determined according to the selected preset motor brake and rear axle brake distribution curve and the actual brake pedal travel, and only the rear axle is used for braking.

2. The braking energy recovery method according to claim 1, characterized in that: Before the step of determining the maximum percentage of the braking torque currently available for the motor according to the actual temperature and actual power of the battery, the method includes: The braking torque currently available for the motor is determined based on a preset motor braking torque and speed curve and the current speed of the motor.

3. A braking energy recovery system, characterized in that: include: An ABS controller and a motor controller, wherein the motor controller and the ABS controller are electrically connected; The motor controller is used to determine the maximum percentage of braking torque that the motor can currently use according to the actual temperature and actual power of the battery; The ABS controller is used to select a preset motor braking and rear axle braking distribution curve according to the maximum percentage of the braking torque currently available for the motor, determine the percentage of the actual motor braking torque and the rear axle braking air pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and brake at the percentage of the actual motor braking torque and / or the rear axle braking air pressure; When the actual battery power is not less than the preset battery power or the actual battery temperature is not less than the preset battery temperature, the motor controller is used to determine that the maximum percentage of braking torque currently available for the motor is a%, and a% is 0, and re-braking recovery charging is not recommended at this time; When the actual battery power is less than the preset battery power and the actual battery temperature is less than the preset battery temperature, the motor controller is used to determine the maximum percentage of braking torque that can be currently used by the motor as b% according to the actual battery temperature, 0<b%≤100%, and braking recovery charging is recommended at this time; When the maximum percentage of the braking torque currently available for the motor is greater than 0, the ABS controller is used to determine the percentage of the actual braking torque of the motor and the rear axle braking air pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual travel of the brake pedal, and first use the motor for braking until the percentage of the actual braking torque of the motor reaches the maximum percentage of the braking torque currently available for the motor, and then use the rear axle and the motor together for braking; When the maximum percentage of braking torque currently available to the motor is 0, the ABS controller is used to determine the rear axle brake pressure according to the selected preset motor braking and rear axle braking distribution curve and the actual brake pedal travel, and only use the rear axle for braking.

4. The braking energy recovery system according to claim 3, characterized in that: Also includes: A stroke sensor is provided on the foot brake valve and is electrically connected to the ABS controller. The stroke sensor is used to collect the stroke of the brake pedal.

5. The braking energy recovery system according to claim 3, characterized in that: Also includes: A rear axle control valve group, wherein the rear axle control valve group is provided with a first interface, a second interface, a third interface, a fourth interface, a chamber, a first solenoid valve, a second solenoid valve and a third control valve, wherein the first interface is connected to the air storage compartment, the inlet of the second solenoid valve and the chamber, the fourth interface is connected to the foot brake valve and the inlet of the first solenoid valve, the second interface is connected to the outlet of the chamber and the ABS valve, the third interface is connected to the outside world, the outlet of the first solenoid valve is connected to the chamber and the inlet of the third control valve, the outlet of the second solenoid valve is connected to the inlet of the third control valve, and the outlet of the third control valve is connected to the third interface.

6. An electric vehicle, characterized in that: Comprising a braking energy recovery system as claimed in any one of claims 3 to 5.

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