CN117048357A - Torque distribution method and system for four-wheel drive range-extending power system and vehicle - Google Patents

Torque distribution method and system for four-wheel drive range-extending power system and vehicle Download PDF

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Publication number
CN117048357A
CN117048357A CN202311075308.8A CN202311075308A CN117048357A CN 117048357 A CN117048357 A CN 117048357A CN 202311075308 A CN202311075308 A CN 202311075308A CN 117048357 A CN117048357 A CN 117048357A
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China
Prior art keywords
torque
axle
rear axle
front axle
value
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李蒙娜
叶明辉
汪泊舟
张才干
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Chongqing Changan Automobile Co Ltd
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Chongqing Changan Automobile Co Ltd
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Priority to CN202311075308.8A priority Critical patent/CN117048357A/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
    • B60L15/2045—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 optimising the use of energy
    • 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
    • B60L2220/00—Electrical machine types; Structures or applications thereof
    • B60L2220/40—Electrical machine applications
    • B60L2220/42—Electrical machine applications with use of more than one motor
    • 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
    • B60L2240/10—Vehicle control parameters
    • B60L2240/12—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
    • B60L2240/10—Vehicle control parameters
    • B60L2240/24—Steering angle
    • 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
    • B60L2240/60—Navigation input
    • B60L2240/64—Road conditions
    • B60L2240/642—Slope of road
    • 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
    • B60L2260/00—Operating Modes
    • B60L2260/20—Drive modes; Transition between modes
    • B60L2260/28—Four wheel or all wheel drive

Abstract

The invention relates to a torque distribution method and system of a four-wheel drive range-extending power system and a vehicle, wherein the method comprises the following steps: acquiring the torque required by a driver, and calculating the driving capability boundary values of the front axle and the rear axle; calculating the longitudinal adhesion capacity boundary values of the front shaft and the rear shaft; calculating to obtain a maximum value of the comprehensive torque of the front axle and a minimum value of the comprehensive torque of the front axle based on the driving capability boundary value of the front axle and the longitudinal attachment capability boundary value of the front axle; calculating to obtain a rear axle comprehensive torque maximum value and a rear axle comprehensive torque minimum value based on the driving capability boundary value of the rear axle and the longitudinal attachment capability boundary value of the rear axle; the front axle economic optimal torque and the rear axle economic optimal torque under the current driver demand torque and the vehicle speed are respectively calculated based on the front electric drive efficiency and the rear electric drive efficiency; and calculating to obtain front and rear axle distribution torque, and then obtaining front and rear driving motor target distribution torque respectively through speed ratio conversion. The invention can meet the dynamic requirements of the driver and realize the optimal distribution of energy on the premise of ensuring the safety and stability of the whole vehicle.

Description

Torque distribution method and system for four-wheel drive range-extending power system and vehicle
Technical Field
The invention relates to the technical field of electric control of electric automobiles, in particular to a torque distribution method and system of a four-wheel drive range-extending power system and a vehicle.
Background
The four-wheel drive range-extending power system comprises 4 power sources of an engine, a generator, a main drive motor and an auxiliary drive motor. The engine and the generator form a range-extending system for generating power, the power is not directly involved in driving, and the main driving motor and the auxiliary driving motor respectively drive the rear wheel and the front wheel. Compared with a two-drive automobile, the four-drive automobile can achieve better whole automobile power and drivability. Compared with a four-wheel drive electric automobile, the four-wheel drive range-extending automobile has the advantages that the number of power sources which are required to be coordinated is increased, and the control complexity and difficulty are increased. In the actual running process, the drivability and economy of the whole vehicle are required to be simultaneously considered so as to ensure the optimal comprehensive performance of the whole vehicle.
The method for controlling the front and rear axle driving torque distribution of the four-wheel drive electric vehicle disclosed in the patent document CN107640062B comprises the following steps: s1, calculating a total torque command Td of a driver according to an accelerator pedal and a vehicle speed value; s2, carrying out initial torque distribution based on a system efficiency optimization principle to obtain a front axle initial driving torque Tdf0 and a rear axle initial driving torque Tdr0; s3, estimating an adhesion coefficient available to the road surface to obtain an adhesion coefficient mu; s4, calculating a front axle driving torque limit value Tufmax and a rear axle driving torque limit value Turmax according to the adhesion coefficient mu; s5, adjusting front and rear axle initial torque distribution according to the front axle driving torque limit value Tufmax and the rear axle driving torque limit value Turmax; s6, respectively calculating a front axle motor torque command Tmf and a rear axle motor torque command Tmr, calculating an optimal front and rear axle driving force limit value by identifying road adhesion coefficients in real time, and accordingly transferring and distributing the front and rear axle driving torques, so that optimal power performance is realized, and wheel slip is actively avoided. Economic and safety considerations are taken into account, but dynamic considerations are not taken into account.
Therefore, it is necessary to provide a torque distribution method, a torque distribution system and a torque distribution vehicle for a four-wheel drive range-extending power system, which can meet the power requirements of a driver and realize the optimal distribution of energy on the premise of ensuring the safety and the stability of the whole vehicle.
Disclosure of Invention
The invention aims to provide a torque distribution method and system for a four-wheel drive range-extending power system and a vehicle, which can meet the power requirements and realize optimal distribution of energy on the premise of ensuring the safety and stability of the whole vehicle.
In order to achieve the above object, a first aspect of the present invention provides a torque distribution method of a four-wheel drive range-extending power system, including:
acquiring a driver demand torque;
calculating to obtain a driving capability boundary value of the front shaft and the rear shaft based on the external characteristics and the working state of the motor;
calculating to obtain a longitudinal attachment capacity boundary value of the front axle and the rear axle based on the current vehicle speed value, the gradient and the steering angle;
calculating to obtain a maximum value T of the comprehensive torque of the front axle based on the driving capability boundary value of the front axle and the longitudinal attachment capability boundary value of the front axle XFmax Torque minimum value T integrated with front axle XFmin ；
Calculating based on the driving capability boundary value of the rear axle and the longitudinal attachment capability boundary value of the rear axle to obtain the maximum value T of the comprehensive torque of the rear axle XRmax Combined torque minimum value T with rear axle XRmin ；
Front axle economic optimal torque T under current driver demand torque and vehicle speed is calculated based on front and rear electric drive efficiency FEco Optimal torque T for rear axle economy REco ；
Calculating to obtain front axle distribution torque T F ＝f(T XFmax ，T FEco ，T XFmin ) And rear axle split torque T R ＝f(T XRmax ，T REco ，T XRmin ) Then the target distribution torque T of the front driving motor is respectively obtained through speed ratio conversion FMotDmd And rear drive motor target distribution torque T RMotDmd 。
Further, according to the current vehicle speed value, the opening degree of an accelerator pedal and the opening degree of a brake pedal, the required torque of the driver is calculated, and the specific required torque is determined through real vehicle calibration.
Further, the driving capability boundary value of the front axle includes a front axle driving torque maximum value T FrntDrvMax Minimum value T of driving torque of front axle FrntDrvMin The drive capability boundary value of the rear axle includes a rear axle drive torque maximum value T RearDrvMax Minimum value T of driving torque of rear axle RearDrvMin ；
The specific calculation mode is as follows: when the working states of the front axle motor and the rear axle motor are torque control, the maximum value T of the front axle driving torque FrntDrvMax And front axle drive torque minimum value T FrntDrvMin The method comprises the following steps:
T FrntDrvMax ＝F FMax ·r FWh l ，
T FrntDrvMin ＝F FMin ·r FWh l ，
maximum value T of rear axle driving torque RearDrvMax And rear axle drive torque minimum value T RearDrvMin The method comprises the following steps:
T RearDrvMax ＝F BMax ·r RWh l ，
T RearDrvMin ＝F BMin ·r RWh l ，
the reverse front axle drive torque and the reverse rear axle drive torque are both zero, wherein F FMax And F FMin Respectively a maximum driving force value and a minimum driving force value of the front motor, F BMax And F BMin Respectively a maximum value and a minimum value of the driving force of the rear motor, r FWhl And r RWhl The front motor to wheel end speed ratio and the rear motor to wheel end speed ratio are respectively.
Further, the longitudinal adhesion capability boundary value of the front axle includes a front axle longitudinal adhesion torque maximum value T XFAdmax The longitudinal attachment capability boundary value of the rear axle includes a rear axle longitudinal attachment torque maximum value T XRAdmax The calculation mode is specifically as follows:
first, the original longitudinal maximum attachment torque T of the whole vehicle is calculated XAdmax_Raw I.e.
Wherein G is the gravity of the automobile, alpha is the road gradient angle, r is the radius of the tire,for the adhesion coefficient F zw Is an air lift force;
secondly, the original longitudinal maximum attachment torque T is based on the steering angle theta of the whole vehicle XAdmax_Raw Correcting to obtain the latest longitudinal maximum attachment torque T of the whole vehicle XAdmax ，T XAdmax ＝T XAdmax_Raw ·cos(θ)；
Then, the maximum value of the front axle longitudinal adhesion torque is calculated as T XFAdmax I.e.
Wherein b is the distance from the mass center of the automobile to the rear axle, r is the tire radius, f is the rolling resistance coefficient, alpha is the road gradient angle, L is the automobile wheelbase, and h g The mass center height of the automobile, M is the mass of the whole automobile, g is the gravity acceleration, I w For moment of inertia of wheel, T Dmd To drive the required torque, F zwF The front axle air lift force is;
finally, calculating the maximum value of the longitudinal attachment torque of the rear axle as T XRAdmax T, i.e XRAdmax ＝T XAdmax -T XFAdmax 。
Further, the front axle integrated torque maximum value T XFmax Torque minimum value T integrated with front axle XFmin The calculation mode of (a) is specifically as follows:
maximum value T of torque longitudinally attached to front axle XFAdmax Maximum value T of driving torque of front axle FrntDrvMax Taking small to obtain the maximum value T of the comprehensive torque of the front axle XFmax I.e.
T XFmax ＝min{T XFAdmax ，T FrntDrvMax }，
Maximum value T of torque longitudinally attached to front axle XFAdmax The reaction is reversed to obtain the-T XFAdmax Then with the front axle driving torque minimum value T FrntDrvMin Obtaining the minimum value T of the comprehensive torque and torque of the front axle XFmin I.e.
T XFmin ＝max{-T XFAdmax ，T FrntDrvMin }，
Maximum value T of comprehensive torque of rear axle XRmax Combined torque minimum value T with rear axle XRmin The calculation mode of (a) is specifically as follows:
maximum value T of torque longitudinally attached to rear axle XRAdmax Maximum value T of driving torque of rear axle RearDrvMax Taking out to obtain the maximum value T of the comprehensive torque of the rear axle XRmax I.e.
T XRmax ＝min{T XRAdmax ，T RearDrvMax }，
Maximum value T of torque longitudinally attached to rear axle XRAdmax The reaction is reversed to obtain the-T XRAdmax Then with the rear axle driving torque minimum value T RearDrvMin Obtaining the minimum value T of the comprehensive torque of the rear axle XRmin I.e.
T XRmin ＝max{-T XRAdmax ，T RearDrvMin }。
Further, the front axle is at an optimal torque T FEco And rear axle economy optimum torque T REco The specific calculation mode of (a) is as follows: based on the front electric drive efficiency and the rear electric drive efficiency and according to the driver demand torque and the current vehicle speed value, the front axle economic optimal torque T under the current driving demand and the vehicle speed is obtained by traversing the front electric drive torque and the rear electric drive torque FEco And rear axle economy optimum torque T REco 。
Further, the front drive motor target distribution torque T is calculated FMotDmd And rear drive motor target distribution torque T RMotDmd The specific calculation mode of (a) is as follows:
first, the front axle split torque T is calculated F And rear axle split torque T R Through the maximum value T of the total torque of the front axle XFmax Optimal torque T for front axle economy FEco Taking small value and then combining with front axle to obtain torque minimum value T XFmin Obtaining the front axle distribution torque T F The method comprises the steps of carrying out a first treatment on the surface of the Then through the rear axle integrated torque maximum T XRmax Optimal torque T for rear axle economy REco Taking small value and then combining with the minimum value T of the rear axle comprehensive torque XRmin Obtaining the rear axle distribution torque T R I.e.
T F ＝max{min{T XFmax ，T FEco }，T XFmin }，
T R ＝max{min{T XRmax ，T REco }，T XRmin }，
Finally, the target distribution torque T of the front driving motor can be obtained through speed ratio conversion FMotDmd And rear drive motor target distribution torque T RMotDmd ，T FMotDmd ＝T F /r FWhl And T RMotDmd ＝T R /r RWhl 。
Further, the method further comprises the following steps: obtaining target distribution torque T of front driving motor FMotDmd And rear drive motor target distribution torque T RMotDmd Then, determining the target torque T of the engine based on an ECMS energy management strategy EngDmd And a target rotation speed n of the generator GMDmd The specific calculation mode is as follows:
first, calculate the equivalent power P at the engine and motor operating points Equiv ，P Equiv ＝P Eng +s·P Elec ·η Batt Wherein P is Eng Is the engine power, s is the equivalent factor, P Elec Is the motor power eta Batt For battery efficiency, P Eng The calculation mode of (a) is as follows:
wherein T is EngDmd And n GMDmd Engine target torque and generator target rotational speed, respectively, wherein motor power P Elec The calculation mode of (a) is as follows:
wherein T is FMotDmd And n FMotDmd Respectively distributing torque and target rotating speed for a front driving motor target, T RMotDmd And n RMotDmd Respectively distributing torque and target rotating speed eta to a target of a rear driving motor Gen Forwarding motor transfer efficiency for the engine;
then, all equivalent powers P at the current moment Equiv The engine and generator operating point corresponding to the lowest point in (a) is used as the original engine target torque T EngDmd_Raw And the original generator target rotation speed n GMDmd_Raw .
Finally, the original engine target torque T is based on the target of the last moment EngDmd_Raw And the original generator target rotation speed n GMDmd_Raw Filtering to obtain final distributed engine target torque T EngDmd And a target rotation speed n of the generator GMDmd 。
The second aspect of the invention provides a torque distribution system of a four-wheel drive range-extending power system, which comprises a processor and a memory, wherein the memory is stored with a computer program, and the computer program realizes the torque distribution method of the four-wheel drive range-extending power system when being executed by the processor.
A third aspect of the invention provides a vehicle employing a four-drive range-extending powertrain torque distribution system as described above.
The invention provides a torque distribution method, a torque distribution system and a vehicle of a four-wheel drive range-extending power system. And then, respectively calculating the maximum and minimum values of the comprehensive torque of the front and rear axles according to the driving capability boundary values of the front and rear axles and the longitudinal adhesion capability boundary values of the front and rear axles. And finally, determining target distribution torque of the front and rear driving motors through speed ratio conversion based on the maximum and minimum values of the economic optimal torque of the front and rear axles and the comprehensive torque of the front and rear axles. Therefore, the dynamic performance of the whole vehicle can be improved to the maximum extent on the premise of ensuring the safety and stability. In addition, on the basis, the energy management strategy based on ECMS can determine the target torque T of the engine EngDmd And a target rotation speed n of the generator GMDmd The energy economy of the vehicle in the running process is effectively improved.
Drawings
FIG. 1 is a flow chart of a torque distribution method of a four-wheel drive range-extending power system of the present invention;
fig. 2 is a schematic diagram of a range-extending system in the present invention.
Detailed Description
Further advantages and effects of the present invention will become readily apparent to those skilled in the art from the disclosure herein, by referring to the accompanying drawings and the preferred embodiments. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be understood that the preferred embodiments are presented by way of illustration only and not by way of limitation.
It should be noted that the illustrations provided in the following embodiments merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.
Example 1
Referring to fig. 1, the torque distribution method of the four-wheel drive range-extending power system provided by the invention comprises the following steps:
and calculating to obtain the required torque of the driver according to the current vehicle speed value, the opening degree of the accelerator pedal and the opening degree of the brake pedal, wherein the specific required torque is determined through real vehicle calibration.
Based on the external characteristics and the working state of the motor, the driving capability boundary values of the front shaft and the rear shaft are calculated. In the present embodiment, the driving capability boundary value of the front axle includes the maximum value T of the front axle driving torque FrntDrvMax Minimum value T of driving torque of front axle FrntDrvMin The drive capability boundary value of the rear axle includes a rear axle drive torque maximum value T RearDrvMax Minimum value T of driving torque of rear axle RearDrvMin . The specific calculation mode is as follows: when the working states of the front axle motor and the rear axle motor are torque control, the maximum value T of the front axle driving torque FrntDrvMax And front axle drive torque minimum value T FrntDrvMin The method comprises the following steps:
T FrntDrvMax ＝F FMax ·r FWh l ，
T FrntDrvMin ＝F FMin ·r FWh l 。
maximum value T of rear axle driving torque RearDrvMax And rear axle drive torque minimum value T RearDrvMin The method comprises the following steps:
T RearDrvMax ＝F BMax ·r RWh l ，
T RearDrvMin ＝F BMin ·r RWh l 。
the reverse front axle drive torque and the reverse rear axle drive torque are both zero, wherein F FMax And F FMin Respectively a maximum driving force value and a minimum driving force value of the front motor, F BMax And F BMin Respectively a maximum value and a minimum value of the driving force of the rear motor, r FWhl And r RWhl The front motor to wheel end speed ratio and the rear motor to wheel end speed ratio are respectively.
And calculating the longitudinal adhesion capability boundary value of the front axle and the rear axle based on the current vehicle speed value, the gradient and the steering angle. In the present embodiment, the longitudinal adhesion capability boundary value of the front axle includes the front axle longitudinal adhesion torque maximum value T XFAdmax The longitudinal attachment capability boundary value of the rear axle includes a rear axle longitudinal attachment torque maximum value T XRAdmax . The calculation mode is specifically as follows:
first, the original longitudinal maximum attachment torque T of the whole vehicle is calculated XAdmax_Raw I.e.
Wherein G is the gravity of the automobile, alpha is the road gradient angle, r is the radius of the tire,for the adhesion coefficient F zw Is an air lift. Wherein F is zw The method is mainly determined by the windward area and the vehicle speed of the whole vehicle, and is generally obtained based on experimental tests, and is not elaborated here.
Second, the baseMaximum attachment torque T of the steering angle theta of the whole vehicle to the original longitudinal direction XAdmax_Raw Correcting to obtain the latest longitudinal maximum attachment torque T of the whole vehicle XAdmax ，T XAdmax ＝T XAdmax_Raw Cos (θ) present, maximum adhesion torque T to original machine direction XAdmax_Raw The correction is performed because the maximum adhering torque is not completely in the longitudinal direction and may have a lateral torque if the vehicle turns during actual running.
Then, the maximum value of the front axle longitudinal adhesion torque is calculated as T XFAdmax I.e.
Wherein b is the distance from the mass center of the automobile to the rear axle, r is the tire radius, f is the rolling resistance coefficient, alpha is the road gradient angle, L is the automobile wheelbase, and h g The mass center height of the automobile, M is the mass of the whole automobile, g is the gravity acceleration, I w For moment of inertia of wheel, T Dmd To drive the required torque, F zwF Is the front axle air lift. F (F) zwF The method is mainly determined by the windward area and the vehicle speed of the whole vehicle, and is generally obtained based on experimental tests, and is not elaborated here. Finally, calculating the maximum value of the longitudinal attachment torque of the rear axle as T XRAdmax T, i.e XRAdmax ＝T XAdmax -T XFAdmax 。
Calculating to obtain a maximum value T of the comprehensive torque of the front axle based on the driving capability boundary value of the front axle and the longitudinal attachment capability boundary value of the front axle XFmax Torque minimum value T integrated with front axle XFmin . In the present embodiment, the front axle integrated torque maximum value T XFmax Torque minimum value T integrated with front axle XFmin The calculation mode of (a) is specifically as follows:
maximum value T of torque longitudinally attached to front axle XFAdmax Maximum value T of driving torque of front axle FrntDrvMax Taking small to obtain the maximum value T of the comprehensive torque of the front axle XFmax I.e.
T XFmax ＝min{T XFAdmax ，T FrntDrvMax }，
Maximum value T of torque longitudinally attached to front axle XFAdmax The reaction is reversed to obtain the-T XFAdmax Then with the front axle driving torque minimum value T FrntDrvMin Obtaining the minimum value T of the comprehensive torque and torque of the front axle XFmin I.e.
T XFmin ＝max{-T XFAdmax ，T FrntDrvMin }。
The reason why the maximum value of the longitudinal adhesion torque of the front axle is inverted here is because the longitudinal torque is divided into different directions, and the latter reason is the same.
Calculating based on the driving capability boundary value of the rear axle and the longitudinal attachment capability boundary value of the rear axle to obtain the maximum value T of the comprehensive torque of the rear axle XRmax Combined torque minimum value T with rear axle XRmin . In the present embodiment, the rear axle integrated torque maximum value T XRmax Combined torque minimum value T with rear axle XRmin The calculation mode of (a) is specifically as follows:
maximum value T of torque longitudinally attached to rear axle XRAdmax Maximum value T of driving torque of rear axle RearDrvMax Taking out to obtain the maximum value T of the comprehensive torque of the rear axle XRmax I.e.
T XRmax ＝min{T XRAdmax ，T RearDrvMax }，
Maximum value T of torque longitudinally attached to rear axle XRAdmax The reaction is reversed to obtain the-T XRAdmax Then with the rear axle driving torque minimum value T RearDrvMin Obtaining the minimum value T of the comprehensive torque of the rear axle XRmin I.e.
T XRmin ＝max{-T XRAdmax ，T RearDrvMin }。
Front axle economic optimal torque T under current driver demand torque and vehicle speed is calculated based on front and rear electric drive efficiency FEco Optimal torque T for rear axle economy REco . The precursor and post-drive efficiencies are typically based on bench test testing, and are not described in detail herein as being common knowledge to those skilled in the art.
In the present embodiment, the front axle is subjected to the optimum torque T FEco And rear axle economy optimum torque T REco The specific calculation mode of (a) is as follows: based on precursor electric driveEfficiency and rear electric drive efficiency, and according to the driver demand torque and the current vehicle speed value, obtaining the front axle economic optimal torque T under the current driving demand and the vehicle speed by traversing the front electric drive torque and the rear electric drive torque FEco And rear axle economy optimum torque T REco 。
Calculating to obtain front axle distribution torque T F ＝f(T XFmax ，T FEco ，T XFmin ) And rear axle split torque T R ＝f(T XRmax ，T REco ，T XRmin ) Then the target distribution torque T of the front driving motor is respectively obtained through speed ratio conversion FMotDmd And rear drive motor target distribution torque T RMotDmd . In this embodiment, the specific calculation method is as follows: calculating the target distribution torque T of the front driving motor FMotDmd And rear drive motor target distribution torque T RMotDmd The specific calculation mode of (a) is as follows:
first, the front axle split torque T is calculated F And rear axle split torque T R Through the maximum value T of the total torque of the front axle XFmax Optimal torque T for front axle economy FEco Taking small value and then combining with front axle to obtain torque minimum value T XFmin Obtaining the front axle distribution torque T F . Then through the rear axle integrated torque maximum T XRmax Optimal torque T for rear axle economy REco Taking small value and then combining with the minimum value T of the rear axle comprehensive torque XRmin Obtaining the rear axle distribution torque T R I.e.
T F ＝max{min{T XFmax ，T FEco }，T XFmin }，
T R ＝max{min{T XRmax ，T REco }，T XRmin }，
Finally, the target distribution torque T of the front driving motor can be obtained through speed ratio conversion FMotDmd And rear drive motor target distribution torque T RMotDmd ，T FMotDmd ＝T F /r FWhl And T RMotDmd ＝T R /r RWhl °
Referring to fig. 2, in the present embodiment, the solid line represents the mechanical connection, and the dotted line represents the electrical connection. ECMS-based energy management for extended range systemsStrategy for determining engine target torque T EngDmd And a target rotation speed n of the generator GMDmd . The specific calculation mode is as follows:
first, calculate the equivalent power P at the engine and motor operating points Equiv ，P Equiv ＝P Eng +s·P Elec ·η Batt Wherein P is Eng Is the engine power, s is the equivalent factor, P Elec Is the motor power eta Batt For battery efficiency, P Eng The calculation mode of (a) is as follows:
wherein T is EngDmd And n GMDmd Engine target torque and generator target rotational speed, respectively, wherein motor power P Elec The calculation mode of (a) is as follows:
wherein T is FMotDmd And n FMotDmd Respectively distributing torque and target rotating speed for a front driving motor target, T RMotDmd And n RMotDmd Respectively distributing torque and target rotating speed eta to a target of a rear driving motor Gen And forwarding the motor transfer efficiency for the engine. In the actual calculation process, multiple engine target working points are selected at each moment to be compared, i.e. multiple T are present EngDmd And n GMDmd Corresponding equivalent power P Equiv 。
Then, all equivalent powers P at the current moment Equiv The engine and generator operating point corresponding to the lowest point in (a) is used as the original engine target torque T EngDmd_Raw And the original generator target rotation speed n GMDmd_Raw .
Finally, the original engine target torque T is based on the target of the last moment EngDmd_Raw And the original generator target rotation speed n GMDmd_Raw Filtering to obtain final distributed engine target torque T FngDmd And a target rotation speed n of the generator GMDmd . Wherein the purpose of the filtering is to avoid the engine target torque T EngDmd And a target rotation speed n of the generator GMDmd A jump occurs. The last time is defined here as 10ms ago.
Example 2
The invention also provides a torque distribution system of the four-wheel drive range-extending power system, which comprises a processor and a memory, wherein the memory is stored with a computer program, and the torque distribution method of the four-wheel drive range-extending power system is realized when the computer program is executed by the processor.
Example 3
The invention also provides a vehicle, which adopts the four-wheel drive range-extending power system torque distribution system.
In summary, the torque distribution method and system for the four-wheel drive range-extending power system and the vehicle provided by the invention are characterized in that firstly, the required torque of the vehicle is determined, and then the economic optimal torque of the front axle and the rear axle is determined according to the front and the rear electric drive efficiency and the rotating speed. And determining the maximum and minimum values of the total torque of the front and rear shafts according to the maximum and minimum values of the driving torque of the front and rear shafts and the maximum value of the longitudinal attachment torque of the front and rear shafts, and finally determining the target distribution torque of the front and rear driving motor through speed ratio conversion based on the optimal torque of the front and rear shafts and the maximum and minimum values of the total torque of the front and rear shafts. Therefore, the dynamic performance of the whole vehicle can be improved to the maximum extent on the premise of ensuring the safety and stability. In addition, on the basis, the energy management strategy based on ECMS can determine the target torque T of the engine EngDmd And a target rotation speed n of the generator GMDmd The energy economy of the vehicle in the running process is effectively improved.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
Finally, it should be noted that: the above examples are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention, but it should be understood by those skilled in the art that the present invention is not limited thereto, and that the present invention is described in detail with reference to the foregoing examples: any person skilled in the art may modify or easily conceive of the technical solution described in the foregoing embodiments, or perform equivalent substitution of some of the technical features, while remaining within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. The torque distribution method of the four-wheel drive range-extending power system is characterized by comprising the following steps of:
acquiring a driver demand torque;
calculating to obtain a driving capability boundary value of the front shaft and the rear shaft based on the external characteristics and the working state of the motor;
calculating to obtain a longitudinal attachment capacity boundary value of the front axle and the rear axle based on the current vehicle speed value, the gradient and the steering angle;
calculating to obtain a maximum value T of the comprehensive torque of the front axle based on the driving capability boundary value of the front axle and the longitudinal attachment capability boundary value of the front axle XFmax Torque minimum value T integrated with front axle XFmin ；
Calculating based on the driving capability boundary value of the rear axle and the longitudinal attachment capability boundary value of the rear axle to obtain the comprehensive torque of the rear axleMaximum T XRmax Combined torque minimum value T with rear axle XRmin ；
Front axle economic optimal torque T under current driver demand torque and vehicle speed is calculated based on front and rear electric drive efficiency FEco Optimal torque T for rear axle economy REco ；
Calculating to obtain front axle distribution torque T F ＝f(T XFmax ，T FEco ，T XFmin ) And rear axle split torque T R ＝f(T XRmax ，T REco ，T XRmin ) Then the target distribution torque T of the front driving motor is respectively obtained through speed ratio conversion FMotDmd And rear drive motor target distribution torque T RMotDmd 。
2. The four-wheel drive range-extending powertrain torque distribution method of claim 1, wherein: and calculating to obtain the required torque of the driver according to the current vehicle speed value, the opening degree of the accelerator pedal and the opening degree of the brake pedal, wherein the specific required torque is determined through real vehicle calibration.
3. The four-wheel drive range-extending powertrain torque distribution method according to claim 1, wherein the front axle drive capability boundary value includes a front axle drive torque maximum value T FrntDrvMax Minimum value T of driving torque of front axle FrntDrvMin The drive capability boundary value of the rear axle includes a rear axle drive torque maximum value T RearDrvMax Minimum value T of driving torque of rear axle RearDrvMin The specific calculation mode is as follows: when the working states of the front axle motor and the rear axle motor are torque control, the maximum value T of the front axle driving torque FrntDrvMax And front axle drive torque minimum value T FrntDrvMin The method comprises the following steps:
T FrntDrvMax ＝F FMax ·r FWh l ，
T FrntDrvMin ＝F FMin ·r FWh l ，
maximum value T of rear axle driving torque RearDrvMax And rear axle drive torque minimum value T RearDrvMin The method comprises the following steps:
T RearDrvMax ＝F BMax ·r RWh l ，
T RearDrvMin ＝F BMin ·r RWh l ，
the reverse front axle drive torque and the reverse rear axle drive torque are both zero, wherein F FMax And F FMin Respectively a maximum driving force value and a minimum driving force value of the front motor, F BMax And F BMin Respectively a maximum value and a minimum value of the driving force of the rear motor, r FWhl And r RWhl The front motor to wheel end speed ratio and the rear motor to wheel end speed ratio are respectively.
4. The four-wheel drive range-extending powertrain torque distribution method according to claim 1, wherein the longitudinal adhesion capability boundary value of the front axle includes a front axle longitudinal adhesion torque maximum value T XFAdmax The longitudinal attachment capability boundary value of the rear axle includes a rear axle longitudinal attachment torque maximum value T XRAdmax The calculation mode is specifically as follows:
first, the original longitudinal maximum attachment torque T of the whole vehicle is calculated XAdmax_Raw I.e.
Wherein G is the gravity of the automobile, alpha is the road gradient angle, r is the radius of the tire,for the adhesion coefficient F zw Is an air lift force;
secondly, the original longitudinal maximum attachment torque T is based on the steering angle theta of the whole vehicle XAdmax_Raw Correcting to obtain the latest longitudinal maximum attachment torque T of the whole vehicle XAdmax ，T XAdmax ＝T XAdmax_Raw ·cos(θ)；
Then, the maximum value of the front axle longitudinal adhesion torque is calculated as T XFAdmax I.e.
Wherein b is the distance from the mass center of the automobile to the rear axle, r is the tire radius, f is the rolling resistance coefficient, alpha is the road gradient angle, L is the automobile wheelbase, and h g The mass center height of the automobile, M is the mass of the whole automobile, g is the gravity acceleration, I w For moment of inertia of wheel, T Dmd To drive the required torque, F zwF The front axle air lift force is;
finally, calculating the maximum value of the longitudinal attachment torque of the rear axle as T XRAdmax T, i.e XRAdmax ＝T XAdmax -T XFAdmax 。
5. The four-wheel drive range-increasing power system torque distribution method according to claim 1, wherein the front axle integrated torque maximum value T XFmax Torque minimum value T integrated with front axle XFmin The calculation mode of (a) is specifically as follows:
maximum value T of torque longitudinally attached to front axle XFAdmax Maximum value T of driving torque of front axle FrntDrvMax Taking small to obtain the maximum value T of the comprehensive torque of the front axle XFmax I.e.
T XFmax ＝min{T XFAdmax ,T FrntDrvMax }，
Maximum value T of torque longitudinally attached to front axle XFAdmax The reaction is reversed to obtain the-T XFAdmax Then with the front axle driving torque minimum value T FrntDrvMin Obtaining the minimum value T of the comprehensive torque and torque of the front axle XFmin I.e.
T XFmin ＝max{-T XFAdmax ,T FrntDrvMin }，
Maximum value T of comprehensive torque of rear axle XRmax Combined torque minimum value T with rear axle XRmin The calculation mode of (a) is specifically as follows:
maximum value T of torque longitudinally attached to rear axle XRAdmax Maximum value T of driving torque of rear axle RearDrvMax Taking out to obtain the maximum value T of the comprehensive torque of the rear axle XRmax I.e.
T XRmax ＝min{T XRAdmax ,T RearDrvMax },
Maximum value T of torque longitudinally attached to rear axle XRAdmax The reaction is reversed to obtain the-T XRAmax Then with the rear axle driving torque minimum value T RearDrvMin Obtaining the minimum value T of the comprehensive torque of the rear axle XRmin I.e.
T XRmin ＝max{-T XRAdmax ,T RearDrvMin }。
6. The four-wheel drive range-extending powertrain torque distribution method according to claim 1, wherein the front axle is adapted to an optimal torque T FEco And rear axle economy optimum torque T REco The specific calculation mode of (a) is as follows: based on the front electric drive efficiency and the rear electric drive efficiency and according to the driver demand torque and the current vehicle speed value, the front axle economic optimal torque T under the current driving demand and the vehicle speed is obtained by traversing the front electric drive torque and the rear electric drive torque FEco And rear axle economy optimum torque T REco 。
7. The four-wheel drive range-extending powertrain torque distribution method according to claim 1, wherein the front drive motor target distribution torque T is calculated FMotDmd And rear drive motor target distribution torque T FMotDmd The specific calculation mode of (a) is as follows:
first, the front axle split torque T is calculated F And rear axle split torque T R Through the maximum value T of the total torque of the front axle XFmax Optimal torque T for front axle economy FEco Taking small value and then combining with front axle to obtain torque minimum value T XRmin Obtaining the front axle distribution torque T F The method comprises the steps of carrying out a first treatment on the surface of the Then through the rear axle integrated torque maximum T XRmax Optimal torque T for rear axle economy REco Taking small value and then combining with the minimum value T of the rear axle comprehensive torque XRmin Obtaining the rear axle distribution torque T R I.e.
T F ＝max{min{T XFmax ,T FEco },T XFmin }，
T R ＝max{min{T XFmax ,T REco },T XRmin }，
Finally, the purpose of the front driving motor can be obtained through the conversion of the speed ratioTarget torque T FMotDmd And rear drive motor target distribution torque T RMotDmd ,T FMotDmd ＝T F /r FWhl And T RMotDmd ＝T R /r RWhl 。
8. The four-wheel drive range-extending powertrain torque distribution method according to any one of claims 1 to 7, further comprising: obtaining target distribution torque T of front driving motor FMotDmd And rear drive motor target distribution torque T RMotDmd Then, determining the target torque T of the engine based on an ECMS energy management strategy EngDmd And a target rotation speed n of the generator GMDmd The specific calculation mode is as follows:
first, calculate the equivalent power P at the engine and motor operating points Equiv ，P Equiv ＝P Eng +s·P Elec ·η Batt Wherein P is Eng Is the engine power, s is the equivalent factor, P Elec Is the motor power eta Batt For battery efficiency, P Eng The calculation mode of (a) is as follows:
wherein T is EngDmd And n GMDmd Engine target torque and generator target rotational speed, respectively, wherein motor power P Elec The calculation mode of (a) is as follows:
wherein T is FMotDmd And n FMotDmd Respectively distributing torque and target rotating speed for a front driving motor target, T RMotDmd And n RMotDmd Respectively distributing torque and target rotating speed eta to a target of a rear driving motor Gen Forwarding motor transfer efficiency for the engine;
then, all equivalent powers P at the current moment Equiv Corresponding to the lowest point in (a)As the original engine target torque T EngDmd_Raw And the original generator target rotation speed n GMDmd_Raw ；
Finally, the original engine target torque T is based on the target of the last moment EngDmd_Raw And the original generator target rotation speed n GMDmd_Raw Filtering to obtain final distributed engine target torque T EngDmd And a target rotation speed n of the generator GMDmd 。
9. A four-wheel drive range-extending power system torque distribution system comprising a processor and a memory, wherein the memory stores a computer program which, when executed by the processor, implements the four-wheel drive range-extending power system torque distribution method of any one of claims 1-8.
10. A vehicle employing the four-wheel drive range-extending powertrain torque distribution system of claim 9.
CN202311075308.8A 2023-08-25 2023-08-25 Torque distribution method and system for four-wheel drive range-extending power system and vehicle Pending CN117048357A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117755103A (en) * 2024-02-22 2024-03-26 成都赛力斯科技有限公司 Control method and device for vehicle torque and storage medium

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117755103A (en) * 2024-02-22 2024-03-26 成都赛力斯科技有限公司 Control method and device for vehicle torque and storage medium
CN117755103B (en) * 2024-02-22 2024-04-16 成都赛力斯科技有限公司 Control method and device for vehicle torque and storage medium

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