A four-wheel drive range-extending powertrain torque distribution method, system and vehicle

Abstract

The application relates to a four-wheel drive range-extending power system torque distribution method, system and vehicle, which comprises the following steps: obtaining a driver demand torque, calculating driving capability boundary values of front and rear shafts; calculating longitudinal adhesion capability boundary values of the front and rear shafts; calculating a front shaft comprehensive torque maximum value and a front shaft comprehensive torque minimum value based on the driving capability boundary value of the front shaft and the longitudinal adhesion capability boundary value of the front shaft; calculating a rear shaft comprehensive torque maximum value and a rear shaft comprehensive torque minimum value based on the driving capability boundary value of the rear shaft and the longitudinal adhesion capability boundary value of the rear shaft; calculating front and rear shaft economic optimal torques under the current driver demand torque and vehicle speed based on the front and rear electric drive efficiencies; calculating front and rear shaft distribution torques, and then calculating target distribution torques of front and rear drive motors through speed ratio conversion. The application can meet the driver's power demand and realize optimal energy distribution under the premise of ensuring the safety and stability of the whole vehicle.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle electronic control technology, specifically to a torque distribution method, system, and vehicle for a four-wheel drive range-extended power system. Background Technology

[0002] A four-wheel drive range-extended powertrain system comprises four power sources: an engine, a generator, a main drive motor, and a secondary drive motor. The engine and generator, forming the range-extender system, generate electricity and do not directly participate in driving. The main drive motor and secondary drive motor drive the rear and front wheels, respectively. Compared to two-wheel drive vehicles, four-wheel drive vehicles achieve better overall vehicle power and driving performance. Compared to four-wheel drive electric vehicles, four-wheel drive range-extended vehicles require coordination of more power sources, increasing control complexity and difficulty. In actual operation, both drivability and fuel economy must be considered simultaneously to ensure optimal overall vehicle performance.

[0003] For example, patent document CN107640062B discloses a method for controlling the front and rear axle drive torque distribution of a four-wheel drive electric vehicle, including the following steps: S1, calculating the driver's total torque command Td based on the accelerator pedal and vehicle speed; S2, performing initial torque distribution based on the principle of optimal system efficiency, obtaining the initial drive torque Tdf0 of the front axle and the initial drive torque Tdr0 of the rear axle; S3, estimating the available road surface adhesion coefficient to obtain the adhesion coefficient μ; S4, calculating the front axle drive torque limit value Tufmax and the rear axle drive torque limit value Tormax based on the adhesion coefficient μ; S5, adjusting the initial torque distribution between the front and rear axles based on the front axle drive torque limit value Tufmax and the rear axle drive torque limit value Tormax; S6, calculating the front axle motor torque command Tmf and the rear axle motor torque command Tmr respectively, calculating the optimal front and rear axle drive force limit values ​​by real-time identification of the road surface adhesion coefficient, and transferring and distributing the front and rear axle drive torque accordingly, thereby achieving optimal power performance and actively avoiding wheel slippage. This method considers economy and safety, but does not take power performance into account.

[0004] Therefore, it is necessary to provide a torque distribution method, system, and vehicle for a four-wheel drive range-extended power system that can meet the driver's power needs and achieve optimal energy distribution while ensuring the safety and stability of the entire vehicle. Summary of the Invention

[0005] The purpose of this invention is to provide a torque distribution method, system, and vehicle for a four-wheel drive range-extended power system, which can meet power requirements and achieve optimal energy distribution while ensuring the safety and stability of the vehicle.

[0006] To achieve the above objectives, a first aspect of the present invention is to provide a torque distribution method for a four-wheel drive range-extended power system, comprising:

[0007] Obtain the torque required by the driver;

[0008] Based on the motor's external characteristics and operating state, the boundary values ​​of the driving capabilities of the front and rear axles are calculated.

[0009] The longitudinal adhesion boundary values ​​of the front and rear axles are calculated based on the current vehicle speed, slope, and steering angle.

[0010] The maximum combined torque T of the front axle is calculated based on the boundary values ​​of the front axle's driving capability and longitudinal adhesion capability. XFmax Minimum combined torque T with front axle XFmin ;

[0011] The maximum combined torque T of the rear axle is calculated based on the boundary values ​​of the rear axle's driving capability and longitudinal adhesion capability. XRmax Minimum combined torque T of the rear axle XRmin ;

[0012] Based on the efficiency of the front and rear electric drives, the economically optimal front axle torque T under the current driver's required torque and vehicle speed is calculated. FEco With the optimal economic torque T on the rear axle REco ;

[0013] Based on the maximum combined torque T of the front axle XFmax Front axle optimal torque T FEco Minimum combined torque T with front axle XFmin The front axle distributed torque T is calculated. F ,

[0014] Based on the maximum combined torque T of the rear axle XRmax Optimal rear axle torque T REco Minimum combined torque T of the rear axle XRmin The rear axle distributed torque T was calculated. R Then, the target torque T of the front drive motor is obtained by speed ratio conversion. FMotDmd and the target torque distribution T of the rear drive motor RMotDmd .

[0015] Furthermore, based on the current vehicle speed, accelerator pedal opening, and brake pedal opening, the driver's required torque is calculated, and the specific required torque is determined through actual vehicle calibration.

[0016] Furthermore, the front axle's drive capability boundary values ​​include the maximum front axle drive torque T. FrntDrvMax With the minimum front axle drive torque T FrntDrvMin The boundary values ​​of the rear axle's drive capability include the maximum value of the rear axle drive torque T. RearDrvMax Minimum drive torque T of the rear axle RearDrvMin .

[0017] Furthermore, the boundary values ​​for the longitudinal adhesion capability of the front axle include the maximum longitudinal adhesion torque T of the front axle. XFAdmax The longitudinal adhesion capability boundary values ​​of the rear axle include the maximum longitudinal adhesion torque T of the rear axle. XRAdmax The calculation method is as follows:

[0018] First, calculate the original maximum longitudinal adhesion torque T of the entire vehicle. XAdmax_Raw ,Right now

[0019] ,

[0020] Where G is the weight of the car, The slope angle is r, and the tire radius is r. F is the adhesion coefficient. zw For air lift;

[0021] Secondly, based on the vehicle's steering angle For the original longitudinal maximum adhesion torque T XAdmax_Raw The latest maximum longitudinal adhesion torque T of the whole vehicle is obtained by making corrections. XAdmax T XAdmax =T XAdmax_Raw ·cos( );

[0022] Then, the maximum longitudinal adhesion torque of the front axle is calculated as T. XFAdmax ,Right now

[0023] ,

[0024] Where b is the distance from the vehicle's center of gravity to the rear axle, r is the tire radius, and f is the rolling resistance coefficient. Where L is the road slope angle, h is the vehicle wheelbase, and h is the vehicle wheelbase. g M is the height of the car's center of gravity, g is the vehicle's mass, and I is the acceleration due to gravity. w For the moment of inertia of the wheel, T Dmd For driving torque requirements, F zwF This provides air lift for the front axle;

[0025] Finally, the maximum longitudinal adhesion torque T of the rear axle was calculated. XRAdmax That is, T XRAdmax =T XAdmax -T XFAdmax .

[0026] Furthermore, the maximum combined torque T of the front axle XFmax Minimum combined torque T with front axle XFmin The specific calculation method is as follows:

[0027] Maximum longitudinal adhesion torque T on the front axle XFAdmax With the maximum front axle drive torque T FrntDrvMaxTaking the smaller value yields the maximum combined torque T of the front axle. XFmax ,Right now

[0028] T XFmax =min{T XFAdmax T FrntDrvMax},

[0029] Maximum longitudinal adhesion torque T on the front axle XFAdmax Inverting it gives -T XFAdmax Then, with the minimum front axle drive torque T FrntDrvMin Taking the largest value yields the minimum combined front axle torque T. XFmin ,Right now

[0030] T XFmin =max{-T XFAdmax T FrntDrvMin},

[0031] Maximum combined torque of rear axle T XRmax Minimum combined torque T of the rear axle XRmin The specific calculation method is as follows:

[0032] Maximum longitudinal adhesion torque T on the rear axle XRAdmax With the maximum drive torque T of the rear axle RearDrvMax Taking the smaller value yields the maximum combined rear axle torque T. XRmax ,Right now

[0033] T XRmax =min{T XRAdmax T RearDrvMax},

[0034] Maximum longitudinal adhesion torque T on the rear axle XRAdmax Inverting it gives -T XRAdmax Then, with the minimum rear axle drive torque T RearDrvMin Taking the larger value yields the minimum combined rear axle torque T. XRmin ,Right now

[0035] T XRmin =max{-T XRAdmax T RearDrvMin}

[0036] Furthermore, the optimal economic torque T on the front axle FEco With the optimal economic torque T on the rear axle REco The specific calculation method is as follows: Based on the front electric drive efficiency and the rear electric drive efficiency, and according to the driver's required torque and the current vehicle speed, the optimal economic torque T of the front axle under the current driving requirements and vehicle speed is obtained by iterating through the front and rear electric drive torques. FEco and the optimal economic torque T on the rear axle REco .

[0037] Furthermore, the target torque T distributed to the front drive motor is calculated. FMotDmd and the target torque distribution T of the rear drive motor RMotDmd The specific calculation method is as follows:

[0038] First, calculate the front axle torque distribution T. F and rear axle torque distribution T R The maximum combined torque T of the front axle XFmax With the front axle's optimal economic torque T FEco Take the smaller value and then combine it with the minimum combined torque T of the front axle. XFmin Take the larger value to obtain the front axle distributed torque T F Then, by using the maximum combined torque T of the rear axle... XRmax With the optimal economic torque T on the rear axle REco Take the smaller value, and then combine it with the minimum combined rear axle torque T. XRmin Take the larger value to obtain the rear axle distributed torque T R ,Right now

[0039] T F =max{min{T XFmax T FEco}, T XFmin},

[0040] T R =max{min{T XRmax T REco}, T XRmin},

[0041] Finally, the target torque T of the front drive motor can be obtained by speed ratio conversion. FMotDmd and the target torque distribution T of the rear drive motor RMotDmd ,T FMotDmd =T F / r FWhl =T R / r RWhl r FWhl and r RWhl These are the speed ratios from the front motor to the wheel end and the speed ratios from the rear motor to the wheel end, respectively.

[0042] Furthermore, it also includes: obtaining the target distributed torque T of the front drive motor. FMotDmd and the target torque distribution T of the rear drive motor RMotDmd Subsequently, based on the energy management strategy of ECMS, the target torque T of the engine is determined. EngDmd and generator target speed n GMDmd The specific calculation method is as follows:

[0043] First, calculate the equivalent power P at the operating points of the engine and motor. Equiv ,

[0044] P Equiv =P Eng +s·P Elec · , where P Eng Where P is the engine power, s is the equivalent factor, and P is the engine power. Elec For motor power, For battery efficiency, P Eng The calculation method is as follows:

[0045] ,

[0046] Among them, T EngDmd and n GMDmd These are the target torque of the engine and the target speed of the generator, where the motor power P Elec The calculation method is as follows:

[0047] ,

[0048] Among them, T FMotDmd and n FMotDmd The target torque and target speed are respectively allocated to the front drive motor, T RMotDmd and n RMotDmd The target torque and target speed are respectively allocated to the rear drive motor. To improve the efficiency of engine-generator transmission;

[0049] Then, all equivalent power P at the current moment Equiv The lowest point in the equation corresponds to the operating point of the engine and generator, which is used as the original engine target torque T. EngDmd_Raw and the target speed n of the original generator GMDmd_Raw ;

[0050] Finally, based on the target at the previous moment, the original engine target torque T is adjusted accordingly. EngDmd_Raw and the target speed n of the original generator GMDmd_Raw The final target engine torque T is obtained by filtering. EngDmd and generator target speed n GMDmd .

[0051] A second aspect of the present invention provides a torque distribution system for a four-wheel drive range-extended power system, including a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the torque distribution method for the four-wheel drive range-extended power system described above is implemented.

[0052] A third aspect of the present invention provides a vehicle employing the torque distribution system of a four-wheel drive range-extending power system as described above.

[0053] This invention provides a torque distribution method, system, and vehicle for a four-wheel drive range-extended powertrain. First, the required torque is determined. Based on the motor's external characteristics and operating state, the driving capability boundary values ​​for the front and rear axles are calculated. Then, based on the current vehicle speed, gradient, and steering angle, the longitudinal adhesion boundary values ​​for the front and rear axles are calculated. Next, the maximum and minimum combined torque values ​​for the front and rear axles are calculated based on the driving capability boundary values ​​and the longitudinal adhesion boundary values, respectively. Finally, based on the optimal economic torque for the front and rear axles and the maximum and minimum combined torque values, the target torque distribution for the front and rear drive motors is determined through speed ratio conversion. This maximizes the vehicle's power performance while ensuring safety and stability. Furthermore, based on this, the invention utilizes an ECMS-based energy management strategy to determine the engine's target torque T. EngDmd and generator target speed n GMDmd This effectively improves the energy economy of vehicles during operation. Attached Figure Description

[0054] Figure 1 This is a flowchart of the torque distribution method for the four-wheel drive range-extended power system of the present invention;

[0055] Figure 2 This is a schematic diagram of the range extender system in this invention. Detailed Implementation

[0056] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0057] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0058] Example 1

[0059] Please see Figure 1 The present invention provides a torque distribution method for a four-wheel drive range-extended power system, comprising:

[0060] The required torque for the driver is calculated based on the current vehicle speed, accelerator pedal opening, and brake pedal opening. The specific required torque is determined through actual vehicle calibration.

[0061] Based on the motor's external characteristics and operating conditions, the driving capability boundary values ​​for the front and rear axles are calculated. In this embodiment, the driving capability boundary value for the front axle includes the maximum driving torque T of the front axle. FrntDrvMax With the minimum front axle drive torque T FrntDrvMin The boundary values ​​of the rear axle's drive capability include the maximum value of the rear axle drive torque T. RearDrvMax Minimum drive torque T of the rear axle RearDrvMin .

[0062] The longitudinal adhesion capability boundary values ​​for the front and rear axles are calculated based on the current vehicle speed, gradient, and steering angle. In this embodiment, the longitudinal adhesion capability boundary value for the front axle includes the maximum longitudinal adhesion torque T of the front axle. XFAdmax The longitudinal adhesion capability boundary values ​​of the rear axle include the maximum longitudinal adhesion torque T of the rear axle. XRAdmax The calculation method is as follows:

[0063] First, calculate the original maximum longitudinal adhesion torque T of the entire vehicle. XAdmax_Raw ,Right now

[0064] ,

[0065] Where G is the weight of the car, The slope angle is r, and the tire radius is r. F is the adhesion coefficient. zw This is lift generated by air. Where F... zw It is mainly determined by the vehicle's frontal area and speed, and is usually based on experimental tests, so we will not go into details here.

[0066] Secondly, based on the vehicle's steering angle For the original longitudinal maximum adhesion torque T XAdmax_Raw The latest maximum longitudinal adhesion torque T of the whole vehicle is obtained by making corrections. XAdmax T XAdmax =T XAdmax_Raw ·cos( Here, the original longitudinal maximum adhesion torque T is... XAdmax_Raw The reason for the correction is that in actual driving, if the vehicle is turning, the maximum adhesion torque is not entirely along the longitudinal direction, but may have lateral torque, so the correction is made.

[0067] Then, the maximum longitudinal adhesion torque of the front axle is calculated as T. XFAdmax ,Right now

[0068] .

[0069] Where b is the distance from the vehicle's center of gravity to the rear axle, r is the tire radius, and f is the rolling resistance coefficient. Where L is the road slope angle, h is the vehicle wheelbase, and h is the vehicle wheelbase.g M is the height of the car's center of gravity, g is the vehicle's mass, and I is the acceleration due to gravity. w For the moment of inertia of the wheel, T Dmd For driving torque requirements, F zwF This is for the front axle's air lift. F zwF Primarily determined by the vehicle's frontal area and speed, this is usually based on experimental testing and will not be discussed in detail here. Finally, the maximum longitudinal adhesion torque of the rear axle is calculated to be T. XRAdmax That is, T XRAdmax =T XAdmax -T XFAdmax .

[0070] The maximum combined torque T of the front axle is calculated based on the boundary values ​​of the front axle's driving capability and longitudinal adhesion capability. XFmax Minimum combined torque T with front axle XFmin In this embodiment, the maximum combined torque T of the front axle is... XFmax Minimum combined torque T with front axle XFmin The specific calculation method is as follows:

[0071] Maximum longitudinal adhesion torque T on the front axle XFAdmax With the maximum front axle drive torque T FrntDrvMax Taking the smaller value yields the maximum combined torque T of the front axle. XFmax ,Right now

[0072] T XFmax =min{T XFAdmax T FrntDrvMax},

[0073] Maximum longitudinal adhesion torque T on the front axle XFAdmax Inverting it gives -T XFAdmax Then, with the minimum front axle drive torque T FrntDrvMin Taking the largest value yields the minimum combined front axle torque T. XFmin ,Right now

[0074] T XFmin =max{-T XFAdmax T FrntDrvMin}

[0075] The reason for reversing the maximum value of the longitudinal adhesion torque of the front axle here is because the longitudinal torque is divided into different directions, and the reason for the following is the same.

[0076] The maximum combined torque T of the rear axle is calculated based on the boundary values ​​of the rear axle's driving capability and longitudinal adhesion capability. XRmax Minimum combined torque T of the rear axle XRmin In this embodiment, the maximum combined torque T of the rear axle is... XRmax Minimum combined torque T of the rear axle XRminThe specific calculation method is as follows:

[0077] Maximum longitudinal adhesion torque T on the rear axle XRAdmax With the maximum drive torque T of the rear axle RearDrvMax Taking the smaller value yields the maximum combined rear axle torque T. XRmax ,Right now

[0078] T XRmax =min{T XRAdmax T RearDrvMax},

[0079] Maximum longitudinal adhesion torque T on the rear axle XRAdmax Inverting it gives -T XRAdmax Then, with the minimum rear axle drive torque T RearDrvMin Taking the larger value yields the minimum combined rear axle torque T. XRmin ,Right now

[0080] T XRmin =max{-T XRAdmax T RearDrvMin}

[0081] Based on the efficiency of the front and rear electric drives, the economically optimal front axle torque T under the current driver's required torque and vehicle speed is calculated. FEco With the optimal economic torque T on the rear axle REco The efficiency of the front electric drive and the efficiency of the rear electric drive are usually determined based on bench tests, which is common knowledge to those skilled in the art and will not be discussed further here.

[0082] In this embodiment, the optimal economic torque T on the front axle is... FEco With the optimal economic torque T on the rear axle REco The specific calculation method is as follows: Based on the front electric drive efficiency and the rear electric drive efficiency, and according to the driver's required torque and the current vehicle speed, the optimal economic torque T of the front axle under the current driving requirements and vehicle speed is obtained by iterating through the front and rear electric drive torques. FEco and the optimal economic torque T on the rear axle REco .

[0083] Based on the maximum combined torque T of the front axle XFmax Front axle optimal torque T FEco Minimum combined torque T with front axle XFmin The front axle distributed torque T is calculated. F ,

[0084] Based on the maximum combined torque T of the rear axle XRmax Optimal rear axle torque T REco Minimum combined torque T of the rear axle XRmin The rear axle distributed torque T was calculated. R Then, the target torque T of the front drive motor is obtained by speed ratio conversion.FMotDmd and the target torque distribution T of the rear drive motor RMotDmd .

[0085] In this embodiment, the target torque T of the front drive motor is calculated. FMotDmd and the target torque distribution T of the rear drive motor RMotDmd The specific calculation method is as follows:

[0086] First, calculate the front axle torque distribution T. F and rear axle torque distribution T R The maximum combined torque T of the front axle XFmax With the front axle's optimal economic torque T FEco Take the smaller value and then combine it with the minimum combined torque T of the front axle. XFmin Take the larger value to obtain the front axle distributed torque T F Then, by using the maximum combined torque T of the rear axle... XRmax With the optimal economic torque T on the rear axle REco Take the smaller value, and then combine it with the minimum combined rear axle torque T. XRmin Take the larger value to obtain the rear axle distributed torque T R ,Right now

[0087] T F =max{min{T XFmax T FEco}, T XFmin},

[0088] T R =max{min{T XRmax T REco}, T XRmin},

[0089] Finally, the target torque T of the front drive motor can be obtained by speed ratio conversion. FMotDmd and the target torque distribution T of the rear drive motor RMotDmd T FMotDmd =T F / r FWhl T RMotDmd =T R / r RWhl r FWhl and r RWhl These are the speed ratios from the front motor to the wheel end and the speed ratios from the rear motor to the wheel end, respectively.

[0090] Please see Figure 2 In this embodiment, solid lines represent mechanical connections, and dashed lines represent electrical connections. For the range extender system, the target engine torque T is determined based on the ECMS-based energy management strategy. EngDmd and generator target speed n GMDmd The specific calculation method is as follows:

[0091] First, calculate the equivalent power P at the operating points of the engine and motor. Equiv ,

[0092] P Equiv =P Eng +s·P Elec · , where P Eng Where P is the engine power, s is the equivalent factor, and P is the engine power. Elec For motor power, For battery efficiency, P Eng The calculation method is as follows:

[0093] ,

[0094] Among them, T EngDmd and n GMDmd These are the target torque of the engine and the target speed of the generator, where the motor power P Elec The calculation method is as follows:

[0095] ,

[0096] Among them, T FMotDmd and n FMotDmd The target torque and target speed are respectively allocated to the front drive motor, T RMotDmd and n RMotDmd The target torque and target speed are respectively allocated to the rear drive motor. To improve the efficiency of engine-generator transmission;

[0097] Then, all equivalent power P at the current moment Equiv The lowest point in the equation corresponds to the operating point of the engine and generator, which is used as the original engine target torque T. EngDmd_Raw and the target speed n of the original generator GMDmd_Raw ;

[0098] Finally, based on the target at the previous moment, the original engine target torque T is adjusted accordingly. EngDmd_Raw and the target speed n of the original generator GMDmd_Raw The final target engine torque T is obtained by filtering. EngDmd and generator target speed n GMDmd The purpose of filtering is to avoid the engine target torque T. EngDmd and generator target speed n GMDmd A transition has occurred. The previous time point here is defined as 10ms ago.

[0099] Example 2

[0100] The present invention also provides a torque distribution system for a four-wheel drive range-extended power system, including a processor and a memory. The memory stores a computer program, and when the computer program is executed by the processor, it implements the torque distribution method for the four-wheel drive range-extended power system as described above.

[0101] Example 3

[0102] The present invention also provides a vehicle employing the four-wheel drive range-extended power system torque distribution system described above.

[0103] In summary, the present invention provides a torque distribution method, system, and vehicle for a four-wheel drive range-extended powertrain. First, the required torque of the vehicle is determined. Then, based on the efficiency and speed of the front and rear electric drives, the economically optimal torque for the front and rear axles is determined. Next, the maximum and minimum combined torque of the front and rear axles are determined based on the maximum and minimum values ​​of the front and rear axle drive torques and the maximum value of the front and rear axle longitudinal adhesion torques. Finally, based on the economically optimal torque of the front and rear axles and the maximum and minimum combined torque of the front and rear axles, the target torque distribution to the front and rear drive motors is determined through speed ratio conversion. Therefore, the overall vehicle power performance can be maximized while ensuring safety and stability. Furthermore, based on this, the present invention utilizes an ECMS-based energy management strategy to determine the engine's target torque T. EngDmd and generator target speed n GMDmd This effectively improves the energy economy of vehicles during operation.

[0104] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0105] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A torque distribution method for a four-wheel drive range-extended power system, characterized in that, include: Obtain the torque required by the driver; Based on the motor's external characteristics and operating state, the boundary values ​​of the driving capabilities of the front and rear axles are calculated. The front axle's drive capability boundary values ​​include the maximum front axle drive torque T. FrntDrvMax With the minimum front axle drive torque T FrntDrvMin The boundary values ​​of the rear axle's drive capability include the maximum value of the rear axle drive torque T. RearDrvMax Minimum drive torque T of the rear axle RearDrvMin ; The longitudinal adhesion capability boundary values ​​for the front and rear axles are calculated based on the current vehicle speed, gradient, and steering angle; the longitudinal adhesion capability boundary value for the front axle includes the maximum longitudinal adhesion torque T. XFAdmax The longitudinal adhesion capability boundary values ​​of the rear axle include the maximum longitudinal adhesion torque T of the rear axle. XRAdmax The calculation method is as follows: First, calculate the original maximum longitudinal adhesion torque T of the entire vehicle. XAdmax_Raw ,Right now ， Where G is the weight of the car, The slope angle is r, and the tire radius is r. F is the adhesion coefficient. zw For air lift; Secondly, based on the vehicle's steering angle For the original longitudinal maximum adhesion torque T XAdmax_Raw The latest maximum longitudinal adhesion torque T of the whole vehicle is obtained by making corrections. XAdmax T XAdmax =T XAdmax_Raw ·cos( ); Then, the maximum longitudinal adhesion torque of the front axle is calculated as T. XFAdmax ,Right now ， Where b is the distance from the vehicle's center of gravity to the rear axle, r is the tire radius, and f is the rolling resistance coefficient. Where L is the road slope angle, h is the vehicle wheelbase, and h is the vehicle wheelbase. g M is the height of the car's center of gravity, g is the vehicle's mass, and I is the acceleration due to gravity. w For the moment of inertia of the wheel, T Dmd For driving torque requirements, F zwF This provides air lift for the front axle; Finally, the maximum longitudinal adhesion torque T of the rear axle was calculated. XRAdmax That is, T XRAdmax =T XAdmax -T XFAdmax ; The maximum combined torque T of the front axle is calculated based on the boundary values ​​of the front axle's driving capability and longitudinal adhesion capability. XFmax Minimum combined torque T with front axle XFmin ; The maximum combined torque T of the rear axle is calculated based on the boundary values ​​of the rear axle's driving capability and longitudinal adhesion capability. XRmax Minimum combined torque T of the rear axle XRmin ; Based on the efficiency of the front and rear electric drives, the economically optimal front axle torque T under the current driver's required torque and vehicle speed is calculated. FEco With the optimal economic torque T on the rear axle REco ; Based on the maximum combined torque T of the front axle XFmax Front axle optimal torque T FEco Minimum combined torque T with front axle XFmin The front axle distributed torque T is calculated. F , Based on the maximum combined torque T of the rear axle XRmax Optimal rear axle torque T REco Minimum combined torque T of the rear axle XRmin The rear axle distributed torque T was calculated. R Then, the target torque T of the front drive motor is obtained by speed ratio conversion. FMotDmd and the target torque distribution T of the rear drive motor RMotDmd .

2. The torque distribution method for a four-wheel drive range-extended power system according to claim 1, characterized in that: The required torque for the driver is calculated based on the current vehicle speed, accelerator pedal opening, and brake pedal opening. The specific required torque is determined through actual vehicle calibration.

3. The torque distribution method for a four-wheel drive range-extended power system according to claim 1, characterized in that, Maximum combined torque of front axle T XFmax Minimum combined torque T with front axle XFmin The specific calculation method is as follows: Maximum longitudinal adhesion torque T on the front axle XFAdmax With the maximum front axle drive torque T FrntDrvMax Taking the smaller value yields the maximum combined torque T of the front axle. XFmax ,Right now T XFmax =min{T XFAdmax ,T FrntDrvMax }, Maximum longitudinal adhesion torque T on the front axle XFAdmax Inverting it gives -T XFAdmax Then, with the minimum front axle drive torque T FrntDrvMin Taking the largest value yields the minimum combined front axle torque T. XFmin ,Right now T XFmin =max{-T XFAdmax ,T FrntDrvMin }, Maximum combined torque of rear axle T XRmax Minimum combined torque T of the rear axle XRmin The specific calculation method is as follows: Maximum longitudinal adhesion torque T on the rear axle XRAdmax With the maximum drive torque T of the rear axle RearDrvMax Taking the smaller value yields the maximum combined rear axle torque T. XRmax ,Right now T XRmax =min{T XRAdmax ,T RearDrvMax }, Maximum longitudinal adhesion torque T on the rear axle XRAdmax Inverting it gives -T XRAdmax Then, with the minimum rear axle drive torque T RearDrvMin Taking the larger value yields the minimum combined rear axle torque T. XRmin ,Right now T XRmin =max{-T XRAdmax ,T RearDrvMin }。 4. The torque distribution method for a four-wheel drive range-extended power system according to claim 1, characterized in that, Front axle optimal torque T FEco With the optimal economic torque T on the rear axle REco The specific calculation method is as follows: Based on the front electric drive efficiency and the rear electric drive efficiency, and according to the driver's required torque and the current vehicle speed, the optimal economic torque T of the front axle under the current driving requirements and vehicle speed is obtained by iterating through the front and rear electric drive torques. FEco and the optimal economic torque T on the rear axle REco .

5. The torque distribution method for a four-wheel drive range-extended power system according to claim 1, characterized in that, Calculate the target torque distribution T of the front drive motor FMotDmd and the target torque distribution T of the rear drive motor RMotDmd The specific calculation method is as follows: First, calculate the front axle torque distribution T. F and rear axle torque distribution T R The maximum combined torque T of the front axle XFmax With the front axle's optimal economic torque T FEco Take the smaller value and then combine it with the minimum combined torque T of the front axle. XFmin Take the larger value to obtain the front axle distributed torque T F Then, by using the maximum combined torque T of the rear axle... XRmax With the optimal economic torque T on the rear axle REco Take the smaller value, and then combine it with the minimum combined rear axle torque T. XRmin Take the larger value to obtain the rear axle distributed torque T R ,Right now T F =max{min{T XFmax ,T FEco },T XFmin }, T R =max{min{T XRmax ,T REco },T XRmin }, Finally, the target torque T of the front drive motor can be obtained by speed ratio conversion. FMotDmd and the target torque distribution T of the rear drive motor RMotDmd T FMotDmd =T F / r FWhl T RMotDmd =T R / r RWhl r FWhl and r RWhl These are the speed ratios from the front motor to the wheel end and the speed ratios from the rear motor to the wheel end, respectively.

6. The torque distribution method for a four-wheel drive range-extended power system according to any one of claims 1 to 5, characterized in that, Also includes: Obtain the target distributed torque T of the front drive motor FMotDmd and the target torque distribution T of the rear drive motor RMotDmd Subsequently, based on the energy management strategy of ECMS, the target torque T of the engine is determined. EngDmd and generator target speed n GMDmd The specific calculation method is as follows: First, calculate the equivalent power P at the operating points of the engine and motor. Equiv , P Equiv =P Eng +s·P Elec · , where P Eng Where P is the engine power, s is the equivalent factor, and P is the engine power. Elec For motor power, For battery efficiency, P Eng The calculation method is as follows: ， Among them, T EngDmd and n GMDmd These are the target torque of the engine and the target speed of the generator, where the motor power P Elec The calculation method is as follows: ， Among them, T FMotDmd and n FMotDmd The target torque and target speed are respectively allocated to the front drive motor, T RMotDmd and n RMotDmd The target torque and target speed are respectively allocated to the rear drive motor. To improve the efficiency of engine-generator transmission; Then, all equivalent power P at the current moment Equiv The lowest point in the equation corresponds to the operating point of the engine and generator, which is used as the original engine target torque T. EngDmd_Raw and the target speed n of the original generator GMDmd_Raw ; Finally, based on the target at the previous moment, the original engine target torque T is adjusted accordingly. EngDmd_Raw and the target speed n of the original generator GMDmd_Raw The final target engine torque T is obtained by filtering. EngDmd and generator target speed n GMDmd .

7. A torque distribution system for a four-wheel drive range-extended power system, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, it implements the torque distribution method of the four-wheel drive range-extending power system as described in any one of claims 1-6.

8. A vehicle, characterized in that, The torque distribution system of the four-wheel drive range-extending power system as described in claim 7 is adopted.

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