CN113682150A - Pure electric vehicle power system, pure electric vehicle and control method - Google Patents

Pure electric vehicle power system, pure electric vehicle and control method Download PDF

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Publication number
CN113682150A
CN113682150A CN202111054898.7A CN202111054898A CN113682150A CN 113682150 A CN113682150 A CN 113682150A CN 202111054898 A CN202111054898 A CN 202111054898A CN 113682150 A CN113682150 A CN 113682150A
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China
Prior art keywords
motor
clutch
vehicle
wheel
torque
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CN202111054898.7A
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Chinese (zh)
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车显达
刘建康
王燕
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FAW Group Corp
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FAW Group Corp
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Priority to CN202111054898.7A priority Critical patent/CN113682150A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B60L15/2009—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed for braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/32—Control or regulation of multiple-unit electrically-propelled vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L7/00—Electrodynamic brake systems for vehicles in general
    • B60L7/10—Dynamic electric regenerative braking
    • B60L7/18—Controlling the braking effect
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/58—Combined or convertible systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/421—Speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/423—Torque
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/48—Drive Train control parameters related to transmissions
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention relates to the field of vehicles and discloses a pure electric vehicle power system, a pure electric vehicle and a control method, wherein the pure electric vehicle power system provided by the invention is characterized in that a first motor and a second motor are both wheel-side motors, a third motor is a centralized motor, and when the first motor is in transmission connection with a corresponding first wheel through a first clutch and the motors are in transmission connection with the corresponding first wheel through a second clutch, the wheel-side motors and the centralized motor jointly control the vehicle to run; when the first motor and the corresponding first wheel are disconnected through the first clutch and the motor and the corresponding first wheel are disconnected through the second clutch, the vehicle is controlled to run through the centralized motor independently, the two-wheel drive control and the four-wheel drive control are switched, the two-wheel drive control or the four-wheel drive control is selected conveniently according to actual requirements, and the problem of large energy loss when the four-wheel drive control is adopted for a long time is solved.

Description

Pure electric vehicle power system, pure electric vehicle and control method
Technical Field
The invention relates to the field of vehicles, in particular to a pure electric vehicle power system, a pure electric vehicle and a control method.
Background
The wheel edge motor realizes that the inner wheel and the outer wheel move at different rotating speeds when turning by an electronic differential control technology, a mechanical differential device is omitted, the weight of a power system is favorably reduced, the arrangement structure is simple, the transmission efficiency can be improved, the performance requirement on a motor assembly is reduced, and the like, so that the wheel edge motor is used more and more.
However, the wheel-side motor has larger back-dragging torque under the condition of follow-up rotation, and in order to prevent overhigh back electromotive force and larger weak magnetic current during high-speed running, the consumed electric energy is larger, so that the power consumption of the four-wheel drive adopting the wheel-side motor is higher, and the driving range of the whole vehicle is shorter.
Disclosure of Invention
The invention aims to provide a pure electric vehicle power system, a pure electric vehicle and a control method, which can reduce the energy consumption of the whole vehicle and prolong the endurance mileage of the whole vehicle.
In order to achieve the purpose, the invention adopts the following technical scheme:
the pure electric vehicle comprises two first wheels and two second wheels, wherein one of the first wheels and the second wheels is a front wheel, and the other one of the first wheels and the second wheels is a rear wheel; pure electric vehicles driving system includes:
the output end of the first motor is in transmission connection with one first wheel through a first clutch;
the output end of the second motor is in transmission connection with the other first wheel through a second clutch;
the output end of the third motor is in transmission connection with the two second wheels;
the first motor and the second motor are both wheel-side motors, and the third motor is a centralized motor.
As a preferred technical solution of the power system of the pure electric vehicle, the first clutch is a one-way clutch or a two-way clutch, and the second clutch is a one-way clutch or a two-way clutch.
As a preferable technical solution of the pure electric vehicle power system,
the first motor is connected with the corresponding first wheel through a first main speed reducer, and the first clutch is arranged between the first motor and the first main speed reducer or between the first main speed reducer and the corresponding first wheel;
the second motor is connected with the corresponding first wheel through a second main speed reducer, and the second clutch is arranged between the second motor and the second main speed reducer or between the second main speed reducer and the corresponding first wheel;
and the third motor is in transmission connection with the two second wheels through a transmission unit and a third main speed reducer.
As a preferred technical solution of the pure electric vehicle power system, the third motor is connected to the transmission unit through a third clutch, or the transmission unit is connected to the third main speed reducer through a third clutch, or the third main speed reducer is in transmission connection with the second wheel through a third clutch;
the transmission unit is a gear shifting transmission, and the third clutch is a two-way clutch.
The invention also provides a pure electric vehicle which comprises the pure electric vehicle power system in any scheme.
The invention also provides a control method of the pure electric vehicle, which is applied to the pure electric vehicle and comprises the following steps:
when the vehicle is in a running state, calculating the running torque required by the running of the vehicle;
if the running torque is larger than the maximum torque which can be generated from the third motor to the wheel end, the first motor, the second motor and the third motor drive the vehicle to run together;
and if the running torque is not larger than the maximum torque which can be generated from the third motor to the wheel end, driving the vehicle to run by the third motor.
As a preferred technical solution of the above pure electric vehicle control method, when the vehicle is in a braking state, calculating a braking torque required for braking the vehicle;
and if the braking torque is not larger than the maximum negative torque which can be generated from the third motor to the wheel end, the third motor provides the negative torque to brake the vehicle.
As a preferable technical solution of the above-mentioned pure electric vehicle control method, if the braking torque is greater than a maximum negative torque that can be generated from the third electric machine to the wheel end and the first clutch and the second clutch are both one-way clutches, the vehicle is braked by the negative torque provided by the third electric machine and the torque provided by a hydraulic braking system of the vehicle.
As a preferable technical solution of the control method of the pure electric vehicle,
if the first clutch and the second clutch are both bidirectional clutches and the braking torque is larger than the sum of the maximum negative torques which can be generated from the first motor, the second motor and the third motor to the wheel end, the first motor, the second motor and the third motor provide negative torques and a hydraulic braking system provides torques to brake the vehicle together;
if the first clutch and the second clutch are both bidirectional clutches, the braking torque is not larger than the sum of the maximum negative torques which can be generated from the first motor, the second motor and the third motor to the wheel end, and the braking torque is larger than the maximum negative torque which can be generated from the third motor to the wheel end, the first motor, the second motor and the third motor provide negative torques to brake the vehicle.
As a preferred technical solution of the above-mentioned pure electric vehicle control method, when the vehicle is braked by the negative torque provided by the electric motor, the braking energy generated by the electric motor providing the negative torque is formed into electric energy to be stored in the power battery.
The invention has the beneficial effects that: according to the pure electric vehicle power system provided by the invention, the first motor and the second motor both adopt wheel-side motors, the third motor adopts a centralized motor, and when the first motor is in transmission connection with the corresponding first wheel through the first clutch and the motor is in transmission connection with the corresponding first wheel through the second clutch, the wheel-side motors and the centralized motor can jointly control the vehicle to run; when the first motor is disconnected with the corresponding first wheel through the first clutch and the motor is disconnected with the corresponding first wheel through the second clutch, the centralized motor can be used for independently controlling the vehicle to run. By adopting the pure electric vehicle system, the switching between the two-wheel drive control and the four-wheel drive control can be realized, the two-wheel drive or four-wheel drive control can be conveniently selected according to actual requirements, and the problem of large energy loss when the four-wheel drive control is adopted for a long time is solved.
According to the pure electric vehicle and the control method provided by the invention, the first motor, the second motor and the third motor are selectively controlled to drive the vehicle to run together or the third motor is controlled to drive the vehicle to run independently according to the running torque required by the vehicle to run, because the third motor is a centralized motor, when the centralized motor drives the vehicle to run independently, the first motor and the second motor are in a static state, namely the first motor and the second motor do not work, the first motor and the second motor can not generate weak magnetic current to consume electric quantity at the moment and can not generate resistance, and the vehicle is driven to run independently by the third motor, so that the vehicle resistance is smaller, the power consumption of the whole vehicle is small, and the endurance mileage of the vehicle is longer.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a pure electric vehicle power system according to a first embodiment of the present invention;
FIG. 2 is a flowchart of vehicle driving control in a control method of a pure electric vehicle powertrain according to an embodiment of the present invention;
FIG. 3 is a graph showing a relationship between a vehicle speed and a running torque output from a third motor to a wheel end when the control system of the pure electric vehicle in the first embodiment is adopted;
FIG. 4 is a flowchart of vehicle braking control in a control method of a pure electric vehicle powertrain according to an embodiment of the present invention;
FIG. 5 is a graph showing a relationship between a vehicle speed and a braking torque output from a third motor to a wheel end when the control system of the pure electric vehicle according to the first embodiment of the present invention is adopted;
FIG. 6 is a flowchart related to vehicle braking control in a pure electric vehicle powertrain control method provided by the second embodiment of the invention;
FIG. 7 is a schematic structural diagram of a pure electric vehicle power system according to a third embodiment of the present invention;
fig. 8 and fig. 9 are schematic structural diagrams of a pure electric vehicle control system provided by other embodiments, respectively;
fig. 10 is a schematic structural diagram of a pure electric vehicle control system according to a fourth embodiment of the present invention;
FIG. 11 is a graph illustrating a relationship between a vehicle speed and a driving torque output from a third motor to a wheel end when the control system of the pure electric vehicle according to the fourth embodiment of the present invention is adopted;
FIG. 12 is a graph illustrating a relationship between a vehicle speed and a braking torque output from a third motor to a wheel end when the control system of the pure electric vehicle according to the fourth embodiment of the present invention is adopted;
FIG. 13 is a schematic structural diagram of a pure electric vehicle control system according to another embodiment;
fig. 14 is a schematic structural diagram of a pure electric vehicle control system according to a fifth embodiment of the present invention;
FIG. 15 is a schematic structural diagram of a pure electric vehicle control system according to another embodiment;
fig. 16 is a schematic structural diagram of a pure electric vehicle control system according to a sixth embodiment of the present invention;
FIG. 17 is a schematic structural diagram of a pure electric vehicle control system according to another embodiment;
fig. 18 is a schematic structural diagram of a pure electric vehicle control system according to a seventh embodiment of the present invention;
FIG. 19 is a schematic structural diagram of a pure electric vehicle control system according to another embodiment;
fig. 20 is a schematic structural diagram of a pure electric vehicle control system according to an eighth embodiment of the present invention;
FIG. 21 is a schematic structural diagram of a pure electric vehicle control system provided by other embodiments;
fig. 22 is a schematic structural diagram of a pure electric vehicle control system according to a ninth embodiment of the present invention;
fig. 23 is a schematic structural diagram of a pure electric vehicle control system according to another embodiment.
In the figure:
11. a first motor; 12. a first clutch; 13. a first final drive;
21. a second motor; 22. a second clutch; 23. a second final drive;
31. a third motor; 32. a third clutch; 33. a third main reducer; 34. a transmission unit;
41. a front wheel; 42. a rear wheel.
Detailed Description
In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.
Example one
Based on the problems that the power consumption is high and the driving mileage of the whole vehicle is short when a wheel-side motor is adopted to drive the four-wheel-drive vehicle to run and the vehicle is braked in a pure electric vehicle control system in the prior art, the embodiment provides the pure electric vehicle power system to reduce the energy consumption when the wheel-side motor drives the four-wheel-drive vehicle to run and the vehicle is braked.
Fig. 1 is a schematic structural diagram of a pure electric vehicle power system provided in this embodiment, and as shown in fig. 1, the pure electric vehicle includes two first wheels and two second wheels, and in this embodiment, the first wheels are taken as front wheels 41, and the second wheels are taken as rear wheels 42 as an example.
The pure electric vehicle power system provided by the embodiment comprises a first motor 11, a second motor 21 and a third motor 31, wherein the output end of the first motor 11 is in transmission connection with a first wheel through a first clutch 12; the output end of the second motor 21 is in transmission connection with another first wheel through a second clutch 22; the output of the third electric machine 31 is in driving connection with two second wheels.
The first motor 11 and the second motor 21 are both wheel-side motors, the third motor 31 is a centralized motor, and when the first motor 11 is in transmission connection with the corresponding first wheel through the first clutch 12 and the motors are in transmission connection with the corresponding first wheel through the second clutch 22, the wheel-side motors and the centralized motor are used for controlling the running and braking of the vehicle together. When the first motor 11 is disconnected from the corresponding first wheel through the first clutch 12 and the motor is disconnected from the corresponding first wheel through the second clutch 22, the centralized motor alone controls the vehicle to run, and selectively cooperates with a hydraulic braking system of the vehicle to brake.
By adopting the pure electric vehicle system, the switching between the two-wheel drive control and the four-wheel drive control can be realized, the two-wheel drive or four-wheel drive control can be conveniently selected according to actual requirements, and the problem of large energy loss when the four-wheel drive control is adopted for a long time is solved.
In the present embodiment, a one-way clutch is used for each of the first clutch 12 and the second clutch 22. It should be noted that the one-way clutch has only one default state, there is no separation or combination state, and the one-way clutch can only transmit power from one direction to the other direction, and cannot transmit power reversely, without being controlled by the controller. Examples are as follows: when the first clutch 12 is a one-way clutch, the driving force of the first motor 11 can be transmitted to the first final drive 13 through the first clutch 12, so that the vehicle can run forwards, but the vehicle cannot be driven to push backwards; in addition, in the process of forward driving of the vehicle, when the vehicle decelerates under the braking working condition, because of the unidirectional property of the transmission force of the one-way clutch, the first motor 11 cannot generate a resistance force which hinders the forward movement of the vehicle, and the first motor 11 also cannot realize the braking energy recovery function, namely, when the one-way clutch is adopted by the first clutch 12, the first motor 11 cannot be controlled to generate a negative torque to brake the vehicle and simultaneously feed back the electric energy to be stored in the power battery.
Further, the first motor 11 is connected with the corresponding first wheel through a first main reducer 13, and the first clutch 12 is arranged between the first motor 11 and the first main reducer 13; the second motor 21 is connected with the corresponding first wheel through a second main reducer 23, and the second clutch 22 is arranged between the second motor 21 and the second main reducer 23; the third electric machine 31 is in driving connection with the two second wheels via a transmission unit 34, a third final drive 33.
The pure electric vehicle power system further comprises a Vehicle Control Unit (VCU), an ESP electrically connected with the vehicle control unit, a first motor controller (MCU1), a second motor controller (MCU2), a third motor controller (MCU3), a power battery and a Battery Management System (BMS).
The battery management system is electrically connected with the power battery, can detect the residual electric quantity (SOC) of the power battery, the temperature of the power battery, the charging and discharging power of the power battery, the fault state of the power battery and the like, and can transmit a detection signal to the vehicle control unit.
First motor controller and first motor 11 electric connection, first motor controller can detect torque, rotational speed, power, temperature and the fault state etc. of first motor 11 to can transmit detected signal to vehicle control unit. The second motor controller is electrically connected with the second motor 21, can detect the torque, the rotating speed, the power, the temperature, the fault state and the like of the second motor 21, and can transmit the detection signal to the vehicle control unit. The third motor controller is electrically connected with the third motor 31, and the third motor controller can detect the torque, the rotating speed, the power, the temperature, the fault state and the like of the third motor 31 and can transmit the detection signal to the vehicle control unit.
The vehicle control unit can send control commands of motor torque and motor speed to the first motor controller, the second motor controller and the third motor controller, and the first motor controller, the second motor controller and the third motor 31 can control the first motor 11, the second motor 21 and the third motor 31 to operate according to the control commands.
The embodiment also provides a pure electric vehicle which comprises the pure electric vehicle power system. The embodiment also provides a control method of the pure electric vehicle, which is applied to the pure electric vehicle.
The control method can be divided into a control method in the running state and a control method in the braking state based on the vehicle state, whether the vehicle is in the running state is judged firstly, if so, the control method in the running state is executed, and if not, the control method in the braking state is executed when the vehicle is in the braking state.
As shown in fig. 2, the control method in the driving state includes the steps of:
and S111, calculating the running torque required by the running of the vehicle.
When the vehicle runs, the vehicle control unit calculates the running torque T _ driver required by the wheel end according to the opening degree of an accelerator pedal, the state of a brake pedal and a vehicle speed signal, namely the running torque required by the vehicle running. The above-described method of calculating the driving torque required for driving the vehicle is prior art in the automotive industry and will not be described in detail herein.
And S112, judging whether the running torque is larger than the maximum torque which can be generated from the third motor 31 to the wheel end, if so, executing S113, and if not, executing S114.
The method of calculating the maximum torque that can be generated by the third motor 31 to the wheel end is as follows: the third motor controller reports the maximum available torque of the third motor 31 as T3_ driver according to the state of the third motor 31maxThe maximum torque that can be generated from the third motor 31 to the wheel end is T3_ drivermaxXi 31, i31 is the product of the speed ratio of the transmission unit 34 and the speed ratio of the third final drive 33.
And S113, driving the vehicle to run by the first motor 11, the second motor 21 and the third motor 31 together.
When the driving torque is larger than the maximum torque which can be generated from the third motor 31 to the wheel end, which indicates that the vehicle is running under a heavy load condition, such as rapid acceleration of the vehicle, uphill slope, high-speed overtaking and the like, the power requirement for running the vehicle cannot be met by the third motor 31 alone, so the first motor 11, the second motor 21 and the third motor 31 drive the vehicle to run together.
Since the first clutch 12 and the second clutch 22 in this embodiment are both one-way clutches, there is no need to control the clutches, and in this case, torque distribution is required for the first motor 11, the second motor 21, and the third motor 31, as follows.
The method for calculating the maximum torque that can be generated by the first electric machine 11 to the wheel end is as follows: the first motor controller reports the maximum available torque T1_ driver of the first motor 11 according to the state of the first motor 11maxThe maximum torque generated from the first motor 11 to the wheel end is T1_ drivermaxAnd xi 11, i11 is the speed ratio of the first final drive 13.
The method of calculating the maximum torque that can be generated by the second electric machine 21 to the wheel end is as follows: the second motor controller reports the maximum available torque T2_ driver of the second motor 21 according to the state of the second motor 21maxThe maximum torque that can be generated from the second electric machine 21 to the wheel end is T2_ drivermaxAnd xi 21, i21 is the speed ratio of the second final drive 23.
The sum of the running torques output to the wheel end by the first motor 11 and the second motor 21 is T1_ driver + T2_ driver, and the running torque output to the wheel end by the third motor 31 is T3_ driver; note that T1_ driver ≦ T1_ drivermax×i11，T2_driver≤T2_drivermax×i21，T3_driver≤T3_drivermax×i31。
The vehicle-mounted controller is characterized in that T1_ driver + T2_ driver is y2 multiplied by T _ driver, T3_ driver is y1 multiplied by T _ driver, y1+ y2 is 1, and y1 and y2 are determined according to the requirements and the optimal performance of the whole vehicle. Illustratively, T1_ driver ═ T2_ driver, y1 ═ y2 ═ 1/2. It should be noted that specific values of y1 and y2 are not limited to the above limitations, and T1_ driver and T2_ driver may not be equal.
And S114, driving the vehicle to run by the third motor 31.
When the running torque is not greater than the maximum torque which can be generated from the third motor 31 to the wheel end, which indicates that the vehicle runs under a low-load working condition, such as vehicle starting, smooth acceleration, high-speed stable running and the like, the power requirement for running of the vehicle can be met by solely relying on the third motor 31, so that the vehicle can be driven by the third motor 31 to run.
Fig. 3 is a graph of the relationship between the vehicle speed and the running torque output from the third motor to the wheel end provided in the present embodiment, and referring to fig. 3, when the running torque is not greater than the maximum torque that can be generated from the third motor 31 to the wheel end, in the region a shown in fig. 3, the third motor 31 is controlled to output power according to the running torque, and the first motor 11 and the second motor 21 are in a stationary state and do not output torque.
Because first motor 11 and second motor 21 do not work, and first motor 11 and second motor 21 are the wheel limit motor, consequently first motor 11 and second motor 21 can not produce weak magnetic current power consumption this moment, also can not produce the resistance, and it is littleer to rely on third motor 31 to drive the vehicle to travel alone, and vehicle resistance is less, and whole car power consumption is little, and the continuation of the journey mileage of vehicle is longer.
As shown in fig. 4, the control method in the braking state includes the steps of:
and S121, calculating the braking torque required by vehicle braking.
The vehicle control unit calculates the braking torque T _ brake required by the wheel end according to the pressure of the brake master cylinder of the driver, the state of the accelerator pedal and the like, namely the braking torque required by the vehicle braking. The above-described method of calculating the braking torque required for braking the vehicle is prior art in the automotive industry and will not be described in detail herein.
And S122, judging whether the braking torque is larger than the maximum negative torque which can be generated from the third motor 31 to the wheel end, if so, executing S123, and if not, executing S124.
The maximum allowable braking torque of the third motor 31 itself is T3_ brakemaxMaximum negative load generated from the third motor 31 to the wheel endTorque T3_ brakemaxXi 31, i31 is the product of the speed ratio of the transmission unit 34 and the speed ratio of the third final drive 33.
And S123, braking the vehicle by the aid of the negative torque provided by the third motor 31 and the torque provided by a hydraulic braking system of the vehicle.
When the braking torque is greater than the maximum negative torque which can be generated from the third motor 31 to the wheel end, it is indicated that emergency braking is performed at this time, the driver re-steps on the brake pedal, the demand for the braking torque is large, and braking by the negative torque provided by the third motor 31 alone cannot meet the demand for the braking torque.
When the braking torque is larger than the maximum negative torque which can be generated from the third motor 31 to the wheel end, the negative torque generated from the third motor 31 to the wheel end is T3_ brakemaxX i31, torque T _ brake' T _ brake-T3 _ brake provided by the hydraulic brake system for brakingmaxAnd the multiplied by i31, so that the third motor 31 can generate the maximum braking energy, and the braking energy generated by the third motor 31 can be conveniently formed into electric energy to be stored in a power battery, thereby realizing energy recycling.
And S124, providing negative torque by the third motor 31 to brake the vehicle.
When the braking torque is not greater than the maximum negative torque which can be generated from the third motor 31 to the wheel end, it indicates that the braking torque requirement can be met by braking with the negative torque provided by the third motor 31 alone, the vehicle control unit sends a control command to the first motor controller, the second motor controller and the third motor controller according to the braking torque, the vehicle is braked with the negative torque provided by the third motor 31 alone, the first motor 11 and the second motor 21 are both static and do not work, the braking torque is not output, the electric energy is not recycled, and the electric energy is not consumed. Fig. 5 is a graph of the relationship between the vehicle speed and the braking torque output from the third motor to the wheel end, and referring to fig. 5, when the braking torque is not greater than the maximum negative torque that can be generated from the third motor 31 to the wheel end, in the region a1 shown in fig. 5, the third motor 31 is controlled to output power according to the braking torque. Because the third motor 31 is a centralized motor, compared with a permanent magnet synchronous motor, the centralized motor has higher efficiency of recovering electric energy, and is more favorable for reducing the electric energy consumption of the whole vehicle.
Example two
The present embodiment differs from the first embodiment in that a bidirectional clutch is used for both the first clutch 12 and the second clutch 22.
The pure electric vehicle power system provided by the embodiment further comprises a clutch controller, wherein the clutch controller is electrically connected with a vehicle control unit (TCU), the clutch controller is electrically connected with the first clutch 12 and the second clutch 22, and the clutch controller can detect the states of the first clutch 12 and the second clutch 22 and transmit a detection signal to the vehicle control unit; the vehicle control unit is capable of adjusting the state of the first clutch 12 and the second clutch 22 via the clutch control.
It should be noted that the bidirectional clutch has three states, namely a separation state, a combination state and a slip state, and the state of the bidirectional clutch can be adjusted by sending a control command to the clutch controller through the vehicle controller. When the bidirectional clutch is in a separation state, parts at two ends of the bidirectional clutch cannot transmit power; when the bidirectional clutch is in a combined state, the parts at the two ends of the bidirectional clutch can normally transmit power; when the two-way clutch is in a slip state, the two-way clutch can transmit a part of power. The following is illustrated in connection with fig. 1: when the first clutch 12 is in the engaged state, the first motor 11 can transmit the driving force to the front wheels 41 to drive the vehicle to run; in the braking process of the vehicle, the first motor 11 can also be controlled to generate power, negative torque is generated to brake the vehicle, and meanwhile, braking energy is recovered. When the first clutch 12 is in the disengaged state, the first motor 11 cannot drive the vehicle, and cannot recover the braking energy, and the first motor 11 also cannot generate resistance to the vehicle.
Since the present embodiment uses different types of the first clutch 12 and the second clutch 22 than the first embodiment, the control method of the pure electric vehicle is different. Based on the pure electric vehicle power system provided by this embodiment, a detailed description is given below of a control method of a power vehicle using the pure electric vehicle power system.
The control method under the driving state comprises the following steps:
and S211, calculating the running torque required by the running of the vehicle.
When the vehicle runs, the vehicle control unit calculates the running torque T _ driver required by the wheel end according to the opening degree of an accelerator pedal, the state of a brake pedal and a vehicle speed signal, namely the running torque required by the vehicle running. The above-described method of calculating the driving torque required for driving the vehicle is prior art in the automotive industry and will not be described in detail herein.
And S212, judging whether the running torque is larger than the maximum torque which can be generated from the third motor 31 to the wheel end, if so, executing S213, and if not, executing S214.
The third motor controller reports the maximum available torque T3 — driver of the third motor 31 depending on the state of the third motor 31maxThe maximum torque that can be generated from the third motor 31 to the wheel end is T3_ drivermaxXi 31, i31 is the product of the speed ratio of the transmission unit 34 and the speed ratio of the third final drive 33.
And S213, driving the vehicle to run by the first motor 11, the second motor 21 and the third motor 31 together.
When the driving torque is larger than the maximum torque which can be generated from the third electric machine 31 to the wheel end, it is described that the power requirement for driving the vehicle cannot be met by the third electric machine 31 alone. Since the first clutch 12 and the second clutch 22 in this embodiment are both bidirectional clutches, when the driving torque is greater than the maximum torque that can be generated from the third motor 31 to the wheel end, the vehicle controller sends a command to the clutch controller to switch the first clutch 12 and the second clutch 22 to the engaged state, so as to realize that the vehicle is driven by the first motor 11, the second motor 21 and the third motor 31 together to run. In this case, torque distribution is required for the first motor 11, the second motor 21, and the third motor 31, and the specific method is as follows.
The method of the maximum torque that can be generated by the first electric machine 11 to the wheel end is as follows: the first motor controller reports the maximum available torque T1_ driver of the first motor 11 according to the state of the first motor 11maxThe maximum torque generated from the first motor 11 to the wheel end is T1_ drivermaxAnd xi 11, i11 is the speed ratio of the first final drive 13.
The second motor controller reports the maximum available torque T2_ driver of the second motor 21 according to the state of the second motor 21maxThe maximum torque that can be generated from the second electric machine 21 to the wheel end is T2_ drivermaxAnd xi 21, i21 is the speed ratio of the second final drive 23.
The sum of the running torques output to the wheel end by the first motor 11 and the second motor 21 is T1_ driver + T2_ driver, and the running torque output to the wheel end by the third motor 31 is T3_ driver. Note that T1_ driver ≦ T1_ drivermax×i11，T2_driver≤T2_drivermax×i21，T3_driver≤T3_drivermax×i31。
The vehicle-mounted controller is characterized in that T3_ driver is y1 multiplied by T _ driver, T1_ driver + T2_ driver is y2 multiplied by T _ driver, y1+ y2 is 1, and y1 and y2 are determined according to the requirements and the optimal performance of the whole vehicle. Illustratively, T1_ driver ═ T2_ driver, y1 ═ y2 ═ 1/2. It should be noted that specific values of y1 and y2 are not limited to the above limitations, and T1_ driver and T2_ driver may not be equal.
And S214, driving the vehicle to run by the third motor 31.
When the running torque is not greater than the maximum torque which can be generated from the third motor 31 to the wheel end, which indicates that the power requirement of the vehicle running can be met by solely depending on the third motor 31, the vehicle controller sends a control command to the clutch controller, the first motor controller, the second motor controller and the third motor controller according to the running torque so as to switch the first clutch 12 and the second clutch 22 to the separated state, the first motor 11 and the second motor 21 are stationary and do not work, and the vehicle is driven by the third motor 31 to run alone. Referring to fig. 3 in the first embodiment, when the running torque is not greater than the maximum torque that can be generated from the third motor 31 to the wheel end, in the region a shown in fig. 3, the third motor 31 is controlled to output power according to the running torque, and the first motor 11 and the second motor 21 are in a stationary state and do not output torque.
Because first motor 11 and second motor 21 do not work, and first motor 11 and second motor 21 are the wheel limit motor, consequently first motor 11 and second motor 21 can not produce weak magnetic current power consumption this moment, also can not produce the resistance, and it is littleer to rely on third motor 31 to drive the vehicle to travel alone, and vehicle resistance is less, and whole car power consumption is little, and the continuation of the journey mileage of vehicle is longer.
As shown in fig. 6, the control method in the braking state includes the steps of:
and S221, calculating the braking torque required by the vehicle braking.
The vehicle control unit calculates the braking torque T _ brake required by the wheel end according to the pressure of the brake master cylinder of the driver, the state of the accelerator pedal and the like, namely the braking torque required by the vehicle braking. The above-described method of calculating the braking torque required for braking the vehicle is prior art in the automotive industry and will not be described in detail herein.
S222, judging whether the braking torque is larger than the sum of the maximum negative torques which can be generated from the first motor 11, the second motor 21 and the third motor 31 to the wheel end, if so, executing S223, and if not, executing S224.
The maximum allowable braking torque of the first electric machine 11 itself is T1_ brakemaxThe maximum negative torque generated from the first motor 11 to the wheel end is T1_ brakemaxAnd xi 11, i11 is the speed ratio of the first final drive 13.
The maximum allowable braking torque of the second electric machine 21 is T2_ brakemaxThe maximum negative torque generated from the second motor 21 to the wheel end is T2_ brakemaxAnd xi 21, i21 is the speed ratio of the second final drive 23.
The maximum allowable braking torque of the third motor 31 itself is T3_ brakemaxThe maximum negative torque generated from the third motor 31 to the wheel end is T3_ brakemaxXi 31, i31 is the product of the speed ratio of the transmission unit 34 and the speed ratio of the third final drive 33.
First and second motors 11 and 11The sum of the maximum negative torques that can be generated by the motor 21 and the third motor 31 to the wheel end is equal to T1_ brakemax×i11+T2_brakemax×i21+T3_brakemax×i31。
And S223, braking the vehicle by jointly providing the negative torque by the first motor 11, the second motor 21 and the third motor 31 and providing the torque by a hydraulic braking system of the vehicle.
When the braking torque is larger than the sum of the maximum negative torques which can be generated from the first motor 11, the second motor 21 and the third motor 31 to the wheel end, the emergency braking is performed, and the driver re-steps on the brake pedal, so that the braking torque is greatly required. Although the first clutch 12 and the second clutch 22 in this embodiment are both bidirectional clutches, so that the first motor 11 and the second motor 21 can provide negative torque, the braking by the negative torque provided by the first motor 11, the second motor 21 and the third motor 31 together still cannot meet the braking torque requirement, and therefore, the braking by the negative torque provided by the first motor 11, the second motor 21 and the third motor 31 and the torque provided by the hydraulic braking system of the vehicle together can brake the vehicle.
When the braking torque is larger than the sum of the maximum negative torques which can be generated from the first motor 11, the second motor 21 and the third motor 31 to the wheel end, the vehicle control unit sends a control command to the clutch controller, the first motor controller, the second motor controller and the third motor controller according to the braking torque, so that the first clutch 12 and the second clutch 22 are combined, and the first motor 11, the second motor 21 and the third motor 31 all generate negative torques.
The negative torque output by the first motor 11 to the wheel end is T1_ brakemaxXi 11, and the negative torque output by the second motor 21 to the wheel end is T2_ brakemaxXi 21, and the negative torque output to the wheel end by the third motor 31 is T3_ brakemaxAnd xi 31, the torque provided by the hydraulic brake system for braking is T _ brake'.
T_brake’＝T_brake－T1_brakemax×i11－T2_brakemax×i21－T3_brakemaxX i31 to generate the maximum braking energy for the first motor 11, the second motor 21 and the third motor 31, so as to generate the braking energy for the first motor 11, the second motor 21 and the third motor 31The braking energy is formed into electric energy to be stored in the power battery, and the energy is recycled.
And S224, judging whether the braking torque is larger than the maximum negative torque which can be generated from the third motor 31 to the wheel end, if so, executing S225, and if not, executing S226.
And S225, the first motor 11, the second motor 21 and the third motor 31 provide negative torque to brake the vehicle.
When the braking torque is not greater than the sum of the maximum negative torques which can be generated from the first motor 11, the second motor 21 and the third motor 31 to the wheel end and is greater than the maximum negative torque which can be generated from the third motor 31 to the wheel end, it is shown that the braking demand is relatively large when the driver steps on the brake pedal at this time, although the braking torque demand cannot be met by independently depending on the third motor 31 to provide the negative torque, because the first clutch 12 and the second clutch 22 are both bidirectional clutches, the first motor 11 and the second motor 21 can provide the negative torque, and the braking torque demand can be met by depending on the first motor 11, the second motor 21 and the third motor 31 to provide the negative torque together to perform braking.
When the braking torque is not greater than the sum of the maximum negative torques which can be generated from the first motor 11, the second motor 21 and the third motor 31 to the wheel end and is greater than the maximum negative torque which can be generated from the third motor 31 to the wheel end, the vehicle control unit sends a control command to the clutch controller, the first motor controller, the second motor controller and the third motor controller according to the braking torque, so that the first clutch 12 and the second clutch 22 are combined, and the first motor 11, the second motor 21 and the third motor 31 all generate the negative torques.
The sum of the braking torques output to the wheel ends by the first motor 11 and the second motor 21 is T1_ brake + T2_ brake, and the braking torque output to the wheel ends by the third motor 31 is T3_ brake.
Wherein, T1_ brake + T2_ brake ═ x2 × T _ brake, T3_ brake ═ x1 × T _ brake, x1+ x2 ═ 1, and x1 and x2 are determined according to the braking performance of the wheel-side motor and the centralized motor. Illustratively, x1 ═ x2 ═ 1/2, and T1_ break ═ T2_ break. It should be noted that specific values of x1 and x2 are not limited to the above limitations, and T1_ break and T2_ break may not be equal.
S226, the third electric machine 31 provides negative torque to brake the vehicle.
When the braking torque is not greater than the maximum negative torque which can be generated from the third electric machine 31 to the wheel end, it indicates that the braking torque requirement can be met already by the braking with the negative torque provided by the third electric machine 31 alone, so the vehicle can be braked with the negative torque provided by the third electric machine 31 alone. Although the first clutch 12 and the second clutch 22 are bidirectional clutches to enable the first motor 11 and the second motor 21 to provide braking torques, the centralized motor has higher electric energy recovery efficiency than a wheel-side motor, and is more favorable for reducing the electric energy consumption of the whole vehicle, so that the third motor 31 is selected to provide negative torques to brake the vehicle under the condition.
When the braking torque is not greater than the maximum negative torque which can be generated from the third motor 31 to the wheel end, the vehicle controller sends a control command to the clutch controller, the first motor controller, the second motor controller and the third motor controller according to the braking torque, so that the first clutch 12 and the second clutch 22 are switched to a separated state, the first motor 11 and the second motor 21 are both static and do not work, and the third motor 31 generates the negative torque. Referring to fig. 5 in the first embodiment, when the braking torque is not greater than the maximum negative torque that can be generated from the third motor 31 to the wheel end, in the region a1 shown in fig. 5, the third motor 31 is controlled to output power according to the braking torque, and the first motor 11 and the second motor 21 are in a stationary state and do not output torque.
When the braking torque is not greater than the maximum negative torque that can be generated from the third electric machine 31 to the wheel end, the braking torque is the negative torque that the third electric machine 31 outputs to the wheel end, i.e., T _ brake is T3_ brake.
Because first motor 11 and second motor 21 are wheel limit motor, and third motor 31 is centralized motor, and centralized motor compares wheel limit motor, and centralized motor carries out the efficiency that electric energy was retrieved higher, is favorable to reducing whole car electric energy consumption more.
EXAMPLE III
The present embodiment differs from the first and second embodiments in that, as shown in fig. 7, the first clutch 12 is provided between the first final drive 13 and the corresponding first wheel, and the second clutch 22 is provided between the second final drive 23 and the corresponding first wheel.
The pure electric vehicle control method provided by the embodiment is respectively referred to in the first embodiment and the second embodiment according to the types of the first clutch 12 and the second clutch 22, and the description is not repeated here.
In other embodiments, as shown in fig. 8 and 9, the first wheel may be the rear wheel 42, and the second wheel may be the front wheel 41.
Example four
As shown in fig. 10, the present embodiment further defines the transmission unit 34 as a shift transmission based on the first embodiment, the third electric machine 31 is connected to the transmission unit 34 through a third clutch 32, and the third clutch 32 is a bidirectional clutch.
In this embodiment, use the derailleur of shifting to be the double-gear derailleur as the example, in order to realize automatic shifting, above-mentioned pure electric vehicles driving system still includes the shift controller, shift controller and vehicle control unit electric connection, and the shift controller can send control command to the double-gear derailleur to make the actuating mechanism that shifts of double-gear derailleur take off the gear or put into gear. The pure electric vehicle control method adopting the pure electric vehicle control system provided by the embodiment refers to the first embodiment and the second embodiment according to the types of the first clutch 12 and the second clutch 22, and the description is not repeated here.
When the two-gear transmission is in the first gear, the product of the speed ratio of the two-gear transmission and the speed ratio of the third main speed reducer 33 is i31, and the corresponding maximum vehicle speed is V31; when the two-speed transmission is in two-speed, the product of the speed ratio of the two-speed transmission and the speed ratio of the third final drive 33 is i32, and the corresponding maximum vehicle speed is V32.
Fig. 11 is a graph showing the relationship between the vehicle speed and the running torque output from the third motor to the wheel end, which is provided by the present embodiment, and the shift strategy is as follows: if the vehicle is in a running state and the vehicle speed and the running torque distributed to the third motor 31 are both in the region B in fig. 13, the transmission is preferably in the second gear; if the vehicle speed and the running torque distributed to the third motor 31 are in the region C in fig. 13, the transmission is preferably in first gear. If the vehicle speed and the running torque distributed to the third motor 31 are in the region a in fig. 13, the motor rotation speed N1 corresponding to the first gear operation of the transmission is calculated according to the vehicle speed and the first gear ratio, and the motor rotation speed N2 corresponding to the second gear operation of the transmission is calculated according to the vehicle speed and the second gear ratio, referring to the motor efficiency map shown in fig. 14, fig. 14 shows the relationship between the motor rotation speed and the torque, the torque T1 corresponding to N1 and the torque T2 corresponding to N2 are calculated according to the motor efficiency map, if T1 is greater than T2, the transmission is preferably the first gear, and if T1 is less than T2, the transmission is preferably the second gear.
When the first gear is shifted to the second gear, the clutch is adjusted to the separation state, the gear shifting actuating mechanism is controlled to be shifted, the rotating speed of the third motor 31 is adjusted to the target rotating speed of the second gear, the gear shifting actuating mechanism is controlled to be shifted, the clutch is adjusted to the combination state, and the gear shifting transmission is switched to the second gear. And the second gear target rotating speed is equal to the rotating speed of the motor before gear shifting multiplied by a second gear speed ratio/first gear speed ratio.
When the second gear is shifted down to the first gear, the clutch is adjusted to a separated state, the gear shifting actuating mechanism is controlled to be shifted, the rotating speed of the third motor 31 is adjusted to a target rotating speed of the first gear, the gear shifting actuating mechanism is controlled to be shifted, and then the clutch is adjusted to a combined state, so that the gear shifting transmission is switched to the first gear. The first gear target rotating speed is equal to the rotating speed of the motor before gear shifting multiplied by the first gear speed ratio/the second gear speed ratio.
The control method for shifting by adopting the gear shifting control strategy when the pure electric vehicle runs is as follows:
s51, acquiring the vehicle speed;
s52, determining a target gear according to the vehicle speed;
the method for acquiring the target gear is detailed in the gear shifting strategy.
And S53, switching the gear shifting transmission to the target gear.
It should be noted that the shift control strategy provided in the present embodiment is only applicable to a pure electric vehicle in which a clutch is disposed between the third electric machine 31 and the shift transmission, and the clutch is a bidirectional clutch.
Fig. 12 is a graph showing the relationship between the vehicle speed and the braking torque output from the third motor 31 to the wheel end, and the present embodiment provides the following gear shift strategy: if the vehicle is in a braking state and the vehicle speed and the braking torque distributed to the third electric machine 31 are both in the region B in fig. 13, the transmission is preferably in the second gear; if the vehicle speed and the braking torque distributed to the third motor 31 are in the region C in fig. 13, the transmission is preferably in first gear. If the vehicle speed and the braking torque distributed to the third motor 31 are in the region a in fig. 13, the motor speed N1 corresponding to the first gear operation of the transmission is calculated according to the vehicle speed and the first gear ratio, the motor speed N2 corresponding to the second gear operation of the transmission is calculated according to the vehicle speed and the second gear ratio, the torque T1 corresponding to N1 and the torque T2 corresponding to N2 are calculated according to the motor efficiency map, if T1 is greater than T2, the transmission is preferably the first gear, and if T1 is less than T2, the transmission is preferably the second gear.
In other embodiments, as shown in fig. 13, a first wheel may be provided as the rear wheel 42, and a second wheel may be provided as the front wheel 41.
EXAMPLE five
The present embodiment is different from the fourth embodiment in that, as shown in fig. 14, the first clutch 12 is provided between the first final drive 13 and the corresponding first wheel, and the second clutch 22 is provided between the second final drive 23 and the corresponding first wheel.
The control method of the pure electric vehicle provided by the embodiment is the same as that of the fourth embodiment, and the description is not repeated here.
In other embodiments, as shown in fig. 15, a first wheel may be provided as the rear wheel 42, and a second wheel may be provided as the front wheel 41.
EXAMPLE six
The present embodiment is different from the fourth embodiment in that, as shown in fig. 16, the third clutch 32 is provided between the transmission unit 34 and the third final drive 33, the transmission unit 34 transmits power to the third final drive 33 through the third clutch 32, and the third final drive 33 transmits power to the final drive.
When the pure electric vehicle control system provided by the embodiment is used for controlling the vehicle to run and brake, the third clutch 32 is in the engaged state, and the specific control method is the same as that of the fourth embodiment, and the description is not repeated here.
In other embodiments, as shown in fig. 17, a first wheel may be provided as the rear wheel 42, and a second wheel may be provided as the front wheel 41.
EXAMPLE seven
The present embodiment is different from the sixth embodiment in that, as shown in fig. 18, the first clutch 12 is provided between the first final drive 13 and the corresponding first wheel, and the second clutch 22 is provided between the second final drive 23 and the corresponding first wheel.
The control method of the pure electric vehicle provided by the embodiment is the same as that of the sixth embodiment, and the description is not repeated here.
In other embodiments, as shown in fig. 19, a first wheel may be provided as the rear wheel 42, and a second wheel may be provided as the front wheel 41.
Example eight
The present embodiment differs from the first embodiment in that a third clutch 32 is provided between a third final drive 33 and a second gear as shown in fig. 20.
The control method of the pure electric vehicle provided by the embodiment is the same as that of the sixth embodiment, and the description is not repeated here.
In other embodiments, as shown in fig. 21, a first wheel may be provided as the rear wheel 42, and a second wheel may be provided as the front wheel 41.
Nine embodiments
The present embodiment differs from the eighth embodiment in that, as shown in fig. 22, the first clutch 12 is provided between the first final drive 13 and the corresponding first wheel, and the second clutch 22 is provided between the second final drive 23 and the corresponding first wheel.
The control method of the pure electric vehicle provided by the embodiment is the same as that of the sixth embodiment, and the description is not repeated here.
In other embodiments, as shown in fig. 23, a first wheel may be provided as the rear wheel 42, and a second wheel may be provided as the front wheel 41.
The above embodiments of the present invention are all exemplified by the first clutch 12 and the second clutch 22 being both one-way clutches, or the first clutch 12 and the second clutch 22 being both two-way clutches. It should be noted that the first clutch 12 may be a one-way clutch and the second clutch 22 may be a two-way clutch; or the first clutch 12 is a two-way clutch and the second clutch 22 is a one-way clutch, both of which are within the scope of the present invention. However, in order to ensure the safety when controlling the vehicle to run and brake, when one of the first clutch 12 and the second clutch 22 is a one-way clutch and the other is a two-way clutch, the control method of the pure electric vehicle preferably adopts the control method when both the first clutch 12 and the second clutch 22 are one-way clutches.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Claims (10)

1. The pure electric vehicle comprises two first wheels and two second wheels, wherein one of the first wheels and the second wheels is a front wheel (41), and the other one of the first wheels and the second wheels is a rear wheel (42); the pure electric automobile power system is characterized by comprising:
a first electric machine (11), wherein the output end of the first electric machine (11) is in transmission connection with one first wheel through a first clutch (12);
a second electric machine (21), wherein the output end of the second electric machine (21) is in transmission connection with the other first wheel through a second clutch (22);
a third motor (31), wherein the output end of the third motor (31) is in transmission connection with the two second wheels;
the first motor (11) and the second motor (21) are both wheel-edge motors, and the third motor (31) is a centralized motor.
2. The pure electric vehicle power system according to claim 1, wherein the first clutch (12) is a one-way clutch or a two-way clutch, and the second clutch (22) is a one-way clutch or a two-way clutch.
3. A pure electric vehicle powertrain according to claim 1,
the first motor (11) is connected with the corresponding first wheel through a first main speed reducer (13), and the first clutch (12) is arranged between the first motor (11) and the first main speed reducer (13) or between the first main speed reducer (13) and the corresponding first wheel;
the second motor (21) is connected with the corresponding first wheel through a second main speed reducer (23), and the second clutch (22) is arranged between the second motor (21) and the second main speed reducer (23) or between the second main speed reducer (23) and the corresponding first wheel;
the third motor (31) is in transmission connection with the two second wheels through a transmission unit (34) and a third main speed reducer (33).
4. A pure electric vehicle powertrain according to claim 3, characterised in that the third electric machine (31) is connected to the transmission unit (34) via a third clutch (32), or the transmission unit (34) is connected to the third final drive (33) via a third clutch (32), or the third final drive (33) is in driving connection with the second wheel via a third clutch (32);
the transmission unit (34) is a gear shifting transmission, and the third clutch (32) is a bidirectional clutch.
5. A pure electric vehicle, characterized by comprising the pure electric vehicle power system of any one of claims 1 to 4.
6. The pure electric vehicle control method is applied to the pure electric vehicle in claim 5, and is characterized by comprising the following steps of:
when the vehicle is in a running state, calculating the running torque required by the running of the vehicle;
if the running torque is larger than the maximum torque which can be generated from the third motor (31) to the wheel end, the first motor (11), the second motor (21) and the third motor (31) drive the vehicle to run together;
if the running torque is not larger than the maximum torque which can be generated from the third motor (31) to the wheel end, the third motor (31) drives the vehicle to run.
7. The pure electric vehicle control method according to claim 6,
when the vehicle is in a braking state, calculating the braking torque required by the braking of the vehicle;
if the braking torque is not larger than the maximum negative torque generated from the third motor (31) to the wheel end, the third motor (31) provides negative torque to brake the vehicle.
8. The pure electric vehicle control method according to claim 7, characterized in that if the braking torque is larger than the maximum negative torque which can be generated from the third electric machine (31) to the wheel end and the first clutch (12) and the second clutch (22) are both one-way clutches, the braking of the vehicle is carried out by the combination of the negative torque provided by the third electric machine (31) and the torque provided by a hydraulic braking system of the vehicle.
9. The pure electric vehicle control method according to claim 7,
if the first clutch (12) and the second clutch (22) are both bidirectional clutches and the braking torque is greater than the sum of the maximum negative torques which can be generated from the first motor (11), the second motor (21) and the third motor (31) to the wheel end, the first motor (11), the second motor (21) and the third motor (31) provide negative torques and a hydraulic braking system provides torques to brake the vehicle together;
if the first clutch (12) and the second clutch (22) are both bidirectional clutches, the braking torque is not larger than the sum of the maximum negative torques which can be generated from the first motor (11), the second motor (21) and the third motor (31) to the wheel end, and the braking torque is larger than the maximum negative torque which can be generated from the third motor (31) to the wheel end, the first motor (11), the second motor (21) and the third motor (31) provide negative torques to brake the vehicle.
10. A pure electric vehicle control method according to claim 8 or 9, characterized in that when the vehicle is braked by the negative torque provided by the electric machine, the braking energy generated by the electric machine providing the negative torque is formed into electric energy to be stored in the power battery.
CN202111054898.7A 2021-09-09 2021-09-09 Pure electric vehicle power system, pure electric vehicle and control method Pending CN113682150A (en)

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