Four-wheel drive environment-friendly vehicle, method of distributing drive force thereof, and recording medium

Abstract

The present application relates to a four-wheel drive eco-friendly vehicle, a method of distributing driving force thereof, and a recording medium. A method of distributing driving force of a four-wheel drive (4WD) eco-friendly vehicle includes determining a first allowable range of driving force of each driving force based on determination of travel stability, determining a second allowable range of driving force of each driving wheel based on a system limit of at least one of a first driving source and a second driving source, determining a range of available driving force of a first driving wheel based on the first allowable range of driving force and the second allowable range of driving force, determining a first target driving force of the first driving wheel in the range of available driving force, considering efficiency of the first driving source, and determining a second target driving force of a second driving wheel based on the first target driving force and a requested torque.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an eco-friendly vehicle including a driving motor and a method of controlling a driving force thereof, and particularly, to a four-wheel drive (4WD) eco-friendly vehicle including different power sources for respective driving wheels and a method of controlling a driving force thereof. BACKGROUND

[0002] A general vehicle uses any one of front and rear wheels as a driving wheel, and only two wheels of the four wheels generate a driving force, and thus the vehicle is also called two-wheel drive (2WD). In contrast, a vehicle including front and rear wheels and all of which generate a driving force, all four wheels are driving wheels, and thus the driving method is called four-wheel drive or 4WD.

[0003] Figure 1 FIG. 1 is a diagram illustrating an example of a configuration of a general four-wheel drive.

[0004] Referring to Figure 1 , an engine / transmission controller 11 can control an engine 21 and a transmission 22. A four-wheel drive (4WD) controller 12 can analyze a behavior of the vehicle based on output torque information acquired from the engine / transmission controller 11, wheel speeds of each wheel, longitudinal / lateral acceleration information, etc., and can calculate a distribution ratio of driving forces of a primary driving wheel 31 and a secondary driving wheel 32 to make the driving force of each driving wheel within a limit of a grip between a tire and a road surface. The 4WD controller 12 can control a coupling strength of a hydraulic clutch in a power distributor 23 based on the calculated distribution ratio, and can distribute the driving force to the secondary driving wheel.

[0005] Therefore, the control concept of the 4WD controller 12 is used to distribute power to secure a grip of each driving wheel, and the grip is affected by a friction coefficient and a normal force, which will be described below with reference to Figure 2 .

[0006] Figure 2 FIG. 2 is a diagram illustrating an example of a relationship between input torque and output torque according to a friction coefficient and a normal force.

[0007] In Figure 2 , a horizontal axis indicates input torque, and a vertical axis indicates output torque. Referring to Figure 2 , in a general case, input torque and output torque are maintained in a proportional relationship up to a grip limit depending on a friction coefficient and a normal force between a tire and a road surface. However, when the input torque exceeds the grip limit, the output torque is reduced, and the tire loses a grip and slips on the road surface (i.e., wheel spin occurs). However, as the friction coefficient or the normal force is reduced, the grip limit is also reduced, and thus the four-wheel drive controller needs to continuously determine the grip limit according to a behavior or a condition of the vehicle.

[0008] Therefore, the control of a four-wheel drive controller can be broadly categorized into feedforward control and feedback control.

[0009] Feedforward control includes start-up control, which is related to the longitudinal direction, and turning (maneuvering) control, which is related to the lateral direction.

[0010] In launch control, the four-wheel drive controller reduces the driving force on the corresponding drive wheels because, during sudden acceleration or hill starts, the normal force on some drive wheels (e.g., the front wheels during sudden acceleration or uphill driving) decreases with the weight of the vehicle. In cornering control, understeer occurs when the front wheels have excessive driving force while cornering, resulting in a turning angle smaller than the steering angle; conversely, oversteer occurs when the rear wheels have excessive driving force while cornering, resulting in a turning angle larger than the steering angle. Therefore, the four-wheel drive controller distributes driving force to each drive wheel to prevent understeer or oversteer. In other words, in launch control or cornering control, feedforward control is applied in advance to prevent slippage.

[0011] Feedback control is often used in longitudinal friction control, where feedback control is employed to reduce existing friction in order to overcome irregular friction conditions on road or rough surfaces.

[0012] However, the method of distributing some of the driving force from the main drive wheels to the auxiliary drive wheels based on vehicle behavior characteristics only applies to systems that have a single power transmission path with the drive wheels (similar to...). Figure 1 This is effective in the manner shown. That is, in environmentally friendly vehicles such as electric vehicles (EVs) or hybrid electric vehicles (HEVs), systems that connect separate drive sources to the front and rear wheels respectively require the integration of separation technology for distributing drive force.

[0013] For example, including Figure 1 The hybrid vehicle with the powertrain shown (in which an electric motor (not shown) is additionally installed between the engine 21 and the transmission 22) basically has a single power transmission path; however, when there is no power distributor 23 to transmit driving force to a separate drive source (e.g., a different engine, a different electric motor, or a combination thereof) for the auxiliary drive wheel 32, a separation technology for distributing driving force is required. Summary of the Invention

[0014] Therefore, this disclosure relates to an environmentally friendly vehicle employing four-wheel drive (4WD) to more effectively distribute driving force and a method for controlling vehicle braking.

[0015] The technical problems solved by the implementation methods are not limited to the above-mentioned technical problems, and other technical problems not described herein will become apparent to those skilled in the art based on the following description.

[0016] To achieve these and other advantages, and in accordance with the purposes of this disclosure, as embodied and broadly described herein, a method for distributing driving force to a four-wheel drive (4WD) environmentally friendly vehicle (having a first drive wheel connected to a first drive source and a second drive wheel connected to a second drive source) comprises: determining a first permissible range of driving force for each drive wheel based on a determination of driving stability; determining a second permissible range of driving force for each drive wheel based on system limitations of at least one of the first and second drive sources; determining a range of available driving force for the first drive wheel based on the first and second permissible ranges of driving force; within the range of available driving force, determining a first target driving force for the first drive wheel based on the efficiency of the first drive source; and determining a second target driving force for the second drive wheel based on the first target driving force and a requested torque.

[0017] In another aspect of this disclosure, a four-wheel drive (4WD) environmentally friendly vehicle includes: a first drive source; a first drive wheel connected to the first drive source; a second drive source; a second drive wheel connected to the second drive source; a first controller configured to determine a first permissible range of drive force for each drive wheel based on a determination of driving stability; and a second controller configured to determine a second permissible range of drive force for each drive wheel based on system limitations of at least one of the first and second drive sources, such that a range of available drive force for the first drive wheel is determined based on the first and second permissible ranges of drive force, and within the range of available drive force, a first target drive force for the first drive wheel is determined based on the efficiency of the first drive source, and a second target drive force for the second drive wheel is determined based on the first target drive force and a requested torque. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of this disclosure and are incorporated in and constitute a part of this application, illustrate exemplary embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure. In the drawings:

[0019] Figure 1 This is a diagram illustrating an example of the construction of a typical four-wheel drive system;

[0020] Figure 2 This is a diagram illustrating an example of the relationship between input torque and output torque based on the coefficient of friction and normal force;

[0021] Figure 3 This is a diagram illustrating an example of the construction of a hybrid vehicle applicable to embodiments of this disclosure;

[0022] Figure 4 This is a diagram illustrating an example of a control system according to an embodiment of the present disclosure;

[0023] Figure 5 This is a diagram illustrating an example of the operation of a driving force range determiner according to an embodiment of the present disclosure;

[0024] Figure 6 This is a diagram illustrating another example of the operation of a driving force range determiner according to an embodiment of the present disclosure;

[0025] Figure 7 This is a diagram illustrating an example of the operation of a target driving force determiner according to an embodiment of the present disclosure;

[0026] Figure 8 This is an example of determining the driving force of the drive wheel according to embodiments of this disclosure; and

[0027] Figure 9 This is a flowchart illustrating an example of a process for distributing driving force in a four-wheel drive (4WD) environmentally friendly vehicle according to an embodiment of the present disclosure. Detailed Implementation

[0028] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to facilitate implementation by those skilled in the art. However, the present disclosure can be implemented in various ways and is not limited to the embodiments described herein. In the drawings, for clarity of description, parts unrelated to the description of the present disclosure will be omitted, and similar parts throughout the specification will be indicated by similar reference numerals.

[0029] Throughout this specification, when it is said that a part "includes" a component, this does not mean that other components are excluded, unless otherwise specifically stated otherwise. The same reference numerals will be used throughout the accompanying drawings to refer to the same or similar parts.

[0030] Embodiments of this disclosure provide a method for determining the range of driving force in an environmentally friendly vehicle with different drive sources installed in the front and rear wheels. This method determines the range of driving force based on the driving stability and system conditions of each drive wheel, and ultimately determines the driving force of each drive wheel based on the efficiency of the power transmission system within the range of driving force.

[0031] For example, an environmentally friendly vehicle applicable to this implementation may include a first power source for providing driving force to the front wheels and a second power source for providing driving force to the rear wheels. Here, the first power source may include a first engine or a first motor, or it may be constructed by connecting the first engine and the first motor in parallel or in series / parallel. The second power source may include a second engine different from the first engine or a second motor different from the first motor, or it may be constructed by connecting the second engine and the second motor in parallel or in series / parallel.

[0032] First, refer to Figure 3 The construction of a powertrain to which embodiments of the present disclosure may be applied is described.

[0033] Figure 3 This is a diagram illustrating an example of the construction of a hybrid vehicle applicable to embodiments of this disclosure.

[0034] refer to Figure 3 The drive shaft of the hybrid powertrain, which combines the engine 110 and the first motor 120, can be connected to the first drive wheel 310 via the transmission 150, and the drive shaft of the second motor 140 can be connected to the second drive wheel 320 without the transmission.

[0035] The first and second motors can receive power from battery 170.

[0036] Needless to say, Figure 3 The vehicle configuration described herein is exemplary, and this disclosure is not limited to any particular powertrain combination, as long as the individual drive sources described above are connected to the respective drive wheels and provide driving force. For example, the first drive wheel 310 and the second drive wheel 320 may each be driven by only different electric motors, and a transmission (not shown) may be additionally mounted between the second drive wheel 320 and the second electric motor 140. As another example, the first electric motor 120 may be omitted from the hybrid powertrain, and the first drive wheel 310 may be driven only by the engine 110.

[0037] However, in the following description, for ease of description, Figure 3 The vehicle configuration shown is exemplary, and it is assumed that the first drive wheel 310 is the rear wheel and the second drive wheel 320 is the front wheel.

[0038] Figure 4 This is a diagram illustrating an example of a control system according to an embodiment of the present disclosure.

[0039] refer to Figure 4The hybrid vehicle according to the embodiment may include a hybrid power control unit (HCU) 240 and a four-wheel drive (4WD) controller 260 to determine the driving force of each drive wheel. Needless to say, when different motors are installed in the front and rear wheels respectively, the HCU 240 can be replaced by a controller suitable for the powertrain, and for example, the HCU 240 can be replaced by a vehicle control unit (VCU).

[0040] HCU 240 may include a request torque determiner 241, a system limit determiner 242, a driving force range determiner 243, and a target driving force determiner 244, and the four-wheel drive controller 260 may include a vehicle state determiner 261, a slip controller 262, a start controller 263, and a handling controller 264.

[0041] The vehicle state determiner 261 of the four-wheel drive controller 260 can determine behavioral characteristics related to the driving stability of the vehicle based on at least one of the torque requested by the driver, the speed of each drive wheel, the steering angle, the longitudinal acceleration, and the lateral acceleration. Depending on the behavioral characteristics, the normal force of each drive wheel can be estimated, and the grip limit of each drive wheel can be determined.

[0042] In this case, the slip controller 262 can determine whether slip occurs in each drive wheel, and can transmit the torque limit of each drive wheel determined based on feedback control to the drive force range determiner 243 of the HCU 240.

[0043] The start controller 263 and the steering controller 264 can send the torque limit of each drive wheel (determined by feedforward control in the case of vehicle starting on a slope, sudden acceleration or turning) to the drive force range determiner 243 of the HCU 240.

[0044] Then, the requested torque determiner 241 of HCU 240 can determine the torque requested by the driver based on the accelerator pedal sensor (APS) value, vehicle speed, driving mode setting, etc., and can provide the determined requested torque to another component inside HCU 240 or four-wheel drive controller 260.

[0045] The system limit determiner 242 can determine the system limit driving force for each drive wheel based on the capacity (maximum output, maximum torque, or maximum RPM) of the drive source connected to each of the front and rear wheels, such as an engine or motor, and can send information about the determined driving force to the driving force range determiner 243.

[0046] Taking into account the requested torque determined by the requested torque determiner 241, the system-limited driving force of each drive wheel determined by the system limit determiner 242, the torque limit of each drive wheel based on feedback provided by the four-wheel drive controller 260, and the torque limit of each drive wheel based on feedforward, the driving force range determiner 243 can determine the range of available driving force based on either the front or rear wheels. (See also...) Figure 5 and Figure 6 The method for determining the range of available driving forces by the driving force range determiner 243 is described in detail.

[0047] Figure 5 This is a diagram illustrating an example of the operation of a driving force range determiner according to an embodiment of the present disclosure.

[0048] refer to Figure 5 The driving force range determiner 243 can determine the range of available driving force in the integrated type based on the rear wheels.

[0049] In detail, the minimum value among the following can be determined as the maximum driving force of the rear wheels: the torque limit of the rear wheels for starting control, the torque limit of the rear wheels for turning control, and the torque limit of the rear wheels for slip control due to system limitations.

[0050] Alternatively, the minimum value among the maximum driving force of the front wheels, the torque limit for front wheel start-up control, the torque limit for front wheel cornering control, and the torque limit for front wheel slip control due to system limitations can be determined as the maximum driving force of the front wheels. The minimum driving force of the rear wheels can be determined by subtracting the determined maximum driving force of the front wheels from the torque requested by the driver. In this case, the minimum driving force of the rear wheels can refer to the minimum value that ensures the grip of the front wheels, and the maximum driving force of the rear wheels can refer to the maximum value that ensures the grip of the rear wheels.

[0051] However, like Figure 3 Like the second drive wheel 320, the power connected to the drive shaft of the motor has only a system limit value, which changes according to the battery's state of charge. Therefore, 4WD control features with consistently consistent behavior are required; for example, the cornering control limit could be set to a limit that is always output, regardless of the remaining battery charge. In this case, it can be as follows: Figure 6 The method shown is modified to determine the maximum driving force of the front wheels.

[0052] Figure 6 This is a diagram illustrating another example of the operation of a driving force range determiner according to an embodiment of the present disclosure.

[0053] refer to Figure 6 When calculating the maximum driving force of the drive wheel connected only to the motor, i.e., according toFigure 3 When calculating the maximum driving force of the front wheels, assuming that cornering control is in operation (i.e., activated when cornering control is executed), the torque limit of the front wheel cornering control related to stability during cornering can be replaced by the smaller of the value determined by the steering controller 264 and the maximum driving force that is always available regardless of the battery's state of charge. Here, when a low SoC is preset for battery efficiency and system protection, or in series mode where the battery is charged using engine power, the maximum driving force independent of the battery's state of charge can refer to the maximum driving force output by the motor connected to the corresponding drive wheel.

[0054] When the driving force range determiner 243 determines the range of available driving forces, including the maximum and minimum driving forces of the rear wheels, the target driving force determiner 244 can determine each of the target driving forces of the rear wheels (which correspond to the final driving force) and the target driving forces of the front wheels based on torque, to optimize the efficiency of the drive source connected to the rear wheels within the range of available driving forces. Figure 7 The description is in the middle.

[0055] Figure 7 This is a diagram illustrating an example of the operation of a target driving force determiner according to an embodiment of the present disclosure.

[0056] refer to Figure 7 The target driving force determiner 244 can compare the smaller of the optimal torque for powertrain (drive source) efficiency and the maximum driving force of the rear wheels determined by the driving force range determiner 243 with the larger of the optimal torque and minimum driving force of the rear wheels determined by the driving force range determiner 243, and can determine the larger value as the target driving force of the rear wheels. The target driving force of the front wheels can be obtained by subtracting the determined target driving force of the rear wheels from the torque requested by the driver (drive request torque).

[0057] according to Figure 3 The vehicle shown is configured to transmit the target driving force of the rear wheels to a controller (not shown) for controlling the second motor 140, and to transmit the target driving force of the front wheels to a controller (not shown) for controlling the engine 110 and the first motor 120.

[0058] Figure 8 This is an example of determining the driving force of the drive wheel according to an embodiment of the present disclosure.

[0059] like Figure 8As shown, this can be effective when distributing drive force through the aforementioned process because the drive source responsible for a particular drive wheel determines the output torque within the available force range to achieve maximum efficiency. In particular, when the motor is connected only to a specific drive wheel, steering characteristics can be stably maintained regardless of the battery state, and therefore it may be advantageous not to alter the vehicle's behavior through variable parameters (such as the battery SoC).

[0060] exist Figure 9 The flowchart summarizes the methods for allocating driving forces described so far.

[0061] Figure 9 This is a flowchart illustrating an example of a process for distributing driving force in a 4WD environmentally friendly vehicle according to an embodiment of the present disclosure.

[0062] refer to Figure 9 First, the HCU 240 can determine the torque requested by the driver at the S910.

[0063] At S920, the four-wheel drive controller 260 can determine the vehicle's driving stability based on the torque requested by the driver, longitudinal / lateral acceleration, wheel speed of each wheel, etc., and at S930A, it can determine the allowable range of driving force for each drive wheel based on the determined vehicle driving stability.

[0064] At S930B, HCU 240 can determine the allowable range of driving force for each drive wheel due to system limitations. In this case, for drive wheels connected only to the drive source motor, the output driving force can be further considered without taking into account the battery state.

[0065] At S940, HCU 240 can determine the available driving force for each drive wheel based on the permissible range of driving force for each drive wheel determined according to driving stability and the permissible range of driving force for each drive wheel due to system limitations. For example, the current operation can be performed to obtain the range of available driving force relative to either the front or rear drive wheel.

[0066] Then, HCU 240 can determine the target driving force of the corresponding drive wheel within the range of available forces based on the efficiency characteristics of the powertrain connected to the drive wheel, and determine the range of its available driving force at S950.

[0067] At S960, when the target driving force of one drive wheel is determined, the target driving force of any one drive wheel can be subtracted from the torque requested by the driver to determine the target driving force of the other drive wheel.

[0068] The environmentally friendly vehicle configured as described above, in relation to at least one embodiment of this disclosure, can determine the range of driving force based on the driving stability of each drive wheel and the system condition, and ultimately can determine the driving force of each drive wheel based on the efficiency of the powertrain within the driving force range, thereby improving efficiency.

[0069] Those skilled in the art will recognize that the effects achievable with this disclosure are not limited to those specifically described above, and that other advantages of this disclosure will become clearer from the detailed description.

[0070] This disclosure can also be implemented as computer-readable code on a computer-readable recording medium. A computer-readable recording medium is any data storage device that can store data that can be subsequently read by a computer system. Examples of computer-readable recording media include read-only memory (ROM), random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage devices.

[0071] Therefore, the exemplary embodiments described above should be construed as exemplary and not restrictive in all respects. The scope of this disclosure should be determined by the appended claims and their legal equivalents, rather than by the above description, and all changes falling within the meaning and scope of the appended claims should be included therein.

Claims

1. A method for distributing driving force in a four-wheel drive environmentally friendly vehicle, the four-wheel drive environmentally friendly vehicle comprising a first drive wheel connected to a first drive source and a second drive wheel connected to a second drive source, the method comprising: The first permissible range of driving force for each of the first drive wheel and the second drive wheel is determined based on the determination of driving stability. Based on system limitations of at least one of the first drive source and the second drive source, a second permissible range of driving force for each of the first drive wheel and the second drive wheel is determined; The range of available driving force for the first drive wheel is determined based on the first permissible range of driving force and the second permissible range of driving force; Within the range of available driving force, a first target driving force is determined for the first drive wheel based on the efficiency of the first drive source; as well as The second target driving force of the second drive wheel is determined based on the first target driving force and the requested torque.

2. The method according to claim 1, wherein, The determination of driving stability is performed based on at least one of the wheel speed, longitudinal acceleration, and lateral acceleration of each of the first and second drive wheels.

3. The method according to claim 1, wherein, Determining the first permissible range of driving force includes: The first torque limit for each drive wheel is determined based on feedback control; and The second torque limit for each drive wheel is determined based on feedforward control.

4. The method according to claim 1, wherein, Determining the first permissible range of driving force includes: Determine the initial torque limit for each drive wheel to reduce wheel slippage; and Determine a second torque limit for each drive wheel to prevent a decrease in normal force due to weight transfer or a decrease in driving stability due to cornering.

5. The method according to claim 4, wherein, The range of available driving force for the first drive wheel includes: The minimum value of the torque limit of the first drive wheel in the first allowable range of driving force and the second allowable range of driving force is determined as the first maximum driving force of the first drive wheel; The minimum value of the torque limit of the second drive wheel within the first permissible range of the driving force and the second permissible range of the driving force is determined as the second maximum driving force of the second drive wheel; and The minimum driving force of the first drive wheel is determined by subtracting the second maximum driving force from the torque requested by the driver.

6. The method according to claim 5, wherein, When either the first drive source or the second drive source comprises only a motor, determining the second torque limit for each drive wheel to prevent a decrease in driving stability due to cornering includes: Determine a third torque limit for each drive wheel, said third torque limit being determined based on feedforward control during vehicle cornering; and The second torque limit is determined by the smaller of the third torque limit and the torque output from the motor, which is independent of the state of the battery used to power the motor.

7. The method according to claim 6, wherein, The torque output from the motor, regardless of the state of the battery, includes the torque that can be output during power generation using the motor or the battery at a preset minimum charge state.

8. The method according to claim 1, wherein, The first drive source includes at least one of a first electric motor and a first engine; and The second drive source includes at least one of a second motor and a second engine.

9. A computer-readable recording medium having a program recorded thereon for performing the method according to claim 1.

10. A four-wheel drive environmentally friendly vehicle, the vehicle comprising: First driving source; The first drive wheel connected to the first drive source; Second driving source; The second drive wheel is connected to the second drive source; The first controller is configured to determine a first permissible range of driving force for each of the first drive wheel and the second drive wheel based on a determination of driving stability. as well as A second controller is configured to determine a second permissible range of driving force for each of the first drive wheel and the second drive wheel based on system limitations of at least one of the first drive source and the second drive source, so as to determine a range of available driving force for the first drive wheel based on the first permissible range of driving force and the second permissible range of driving force, and within the range of available driving force, to determine a first target driving force for the first drive wheel based on the efficiency of the first drive source, and to determine a second target driving force for the second drive wheel based on the first target driving force and a requested torque.

11. The four-wheel drive environmentally friendly vehicle according to claim 10, wherein, The driving stability is determined based on at least one of the wheel speed, longitudinal acceleration, and lateral acceleration of each of the first and second drive wheels.

12. The four-wheel drive environmentally friendly vehicle according to claim 10, wherein, The first permissible range of driving force includes a first torque limit for each drive wheel based on feedback control and a second torque limit for each drive wheel based on feedforward control.

13. The four-wheel drive environmentally friendly vehicle according to claim 10, wherein, The first permissible range of driving force includes a first torque limit for each drive wheel to reduce wheel slippage, and a second torque limit for each drive wheel to prevent a decrease in normal force due to weight transfer or a decrease in driving stability due to cornering.

14. The four-wheel drive environmentally friendly vehicle according to claim 13, wherein, The second controller determines the minimum value of the torque limit of the first drive wheel within the first allowable range of the driving force and the second allowable range of the driving force as the first maximum driving force of the first drive wheel, determines the minimum value of the torque limit of the second drive wheel within the first allowable range of the driving force and the second allowable range of the driving force as the second maximum driving force of the second drive wheel, and determines the minimum driving force of the first drive wheel by subtracting the second maximum driving force from the torque requested by the driver.

15. The four-wheel drive environmentally friendly vehicle according to claim 14, wherein, When either the first drive source or the second drive source comprises only a motor, the second controller is configured as follows: Determine a third torque limit for each drive wheel, said third torque limit being determined based on feedforward control during vehicle cornering; and The second torque limit is determined by the smaller of the third torque limit and the torque output from the motor, which is independent of the state of the battery used to power the motor.

16. The four-wheel drive environmentally friendly vehicle according to claim 15, wherein, The torque output from the motor, regardless of the state of the battery, includes the torque that can be output during power generation using the motor or the battery at a preset minimum charge state.

17. The four-wheel drive environmentally friendly vehicle according to claim 10, wherein, The first drive source includes at least one of a first electric motor and a first engine; and The second drive source includes at least one of a second motor and a second engine.

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