Vehicle control device

Abstract

To enhance energy efficiency of a vehicle.SOLUTION: A vehicular control device comprises: a planetary gear mechanism comprising a first rotation element, a second rotation element and a third rotation element; a first wheel connected to the first rotation element through a first passage; a second wheel connected to the second rotation element through a second passage; an engine connected to the third rotation element through a third passage; a motor generator provided in the first passage; a wheel driving clutch positioned between the motor generator and the first wheel; and a control system that controls the motor generator and the wheel driving clutch. The control system has a motor stopping mode in which the wheel driving clutch is controlled into a disengaged state and the motor generator is controlled into a rotation stopped state.SELECTED DRAWING: Figure 7A

Description

[Technical field]

[0001] The present invention relates to a vehicle control device that controls a vehicle. [Background technology]

[0002] Hybrid vehicles equipped with an engine and a motor generator as a power source have been developed (see Patent Documents 1 to 3). Furthermore, as hybrid vehicles, all-wheel drive vehicles in which both the front and rear wheels are driven have also been developed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-43696 A [Patent Document 2] JP 2007-244111 A [Patent Document 3] JP 2020-168971 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in an all-wheel drive vehicle in which the front and rear wheels are driven, there is a problem that the energy loss in the drive path is likely to increase because the drive path is complicated and made up of rotating shafts, gears, etc. For this reason, there is a demand to improve the energy efficiency of the vehicle by reducing the energy loss in the drive path.

[0005] An object of the present invention is to increase the energy efficiency of vehicles. [Means for solving the problem]

[0006] A vehicle control device in one embodiment is a vehicle control device that controls a vehicle, and includes a planetary gear mechanism having a first rotating element, a second rotating element, and a third rotating element, a first wheel connected to the first rotating element via a first path, a second wheel connected to the second rotating element via a second path, an engine connected to the third rotating element via a third path, a motor generator provided on the first path, and a wheel drive clutch provided on the first path and positioned between the motor generator and the first wheel. an electric storage device connected to the motor generator; and a differential limiting clutch that fastens at least two of the first rotating element, the second rotating element, and the third rotating element; a processor and a memory communicatively connected to each other; 、 The wheel drive clutch and said differential limiting clutch A control system for controlling the do. The control system includes: Controlling the differential limiting clutch to a disengaged state; The vehicle has a motor stop mode in which the wheel drive clutch is controlled to a released state and the motor generator is controlled to a rotation stopped state. The control system has a motor regeneration mode in which the limited slip differential clutch is controlled to an engaged state, the wheel drive clutch is controlled to a released state, and the motor generator is controlled to a regenerative state. The control system executes the motor stop mode when the vehicle is decelerating and the SOC of the power storage device exceeds a threshold. The control system executes the motor regeneration mode when the vehicle is decelerating and the SOC of the power storage device falls below the threshold. A vehicle control device according to one embodiment is a vehicle control device for controlling a vehicle, the vehicle control device including a planetary gear mechanism including a first rotating element, a second rotating element, and a third rotating element, a first wheel connected to the first rotating element via a first path, a second wheel connected to the second rotating element via a second path, an engine connected to the third rotating element via a third path, a motor generator provided on the first path, a wheel drive clutch provided on the first path and positioned between the motor generator and the first wheel, a speed change mechanism provided on the third path, and a control system including a processor and a memory communicatively connected to each other, the control system controlling the motor generator, the wheel drive clutch, and the speed change mechanism. The control system has a motor stop mode in which the wheel drive clutch is controlled to a released state and the motor generator is controlled to a rotation stop state. The control system has an all-wheel drive mode in which the wheel drive clutch is controlled to an engaged state and the motor generator is controlled to a powered state. The control system executes an upshift of the speed change mechanism when switching from the motor stop mode to the all-wheel drive mode. Effect of the Invention

[0007] A vehicle control device according to an embodiment of the present invention includes a control system for controlling a motor generator and a wheel drive clutch. The control system has a motor stop mode in which the wheel drive clutch is controlled to a released state and the motor generator is controlled to a rotation stop state. This can improve the energy efficiency of the vehicle. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of the configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a power unit and a rear drive unit. [Diagram 3] FIG. 2 is a diagram showing an example of a power unit, a rear drive unit, and a control system. [Figure 4] FIG. 2 is a diagram simply illustrating the basic structure of each control unit. [Figure 5A]FIG. 11 is a diagram showing the execution status of an all-wheel drive mode and an all-wheel regenerative mode. [Figure 5B] FIG. 13 is a diagram showing an execution state of a front wheel regenerative mode. [Figure 5C] FIG. 11 is a diagram showing an execution status of a motor stop mode. [Figure 6] 4 is a flowchart showing an example of an execution procedure of the driving mode setting control 1. [Figure 7A] FIG. 13 is a diagram showing an execution state of the motor stop mode during coasting. [Figure 7B] FIG. 7B is a collinear diagram showing the operating state of the center differential shown in FIG. 7A. [Figure 8] FIG. 13 is a diagram showing an execution state of a front wheel regenerative mode during coasting. [Figure 9] FIG. 13 is a diagram showing an execution state of an all-wheel regenerative mode during coasting. [Figure 10] 4 is a flowchart showing an example of an execution procedure of a running mode setting control 2. [Figure 11A] FIG. 13 is a diagram showing an execution state of the motor stop mode during high-speed driving. [Figure 11B] FIG. 11B is a collinear diagram showing the operating state of the center differential shown in FIG. 11A. [Figure 12] FIG. 13 is a diagram showing the state in which the all-wheel drive mode is being executed when driving at high speed. [Figure 13] 4 is a flowchart showing an example of an execution procedure of a driving mode switching control. [Figure 14A] FIG. 11 is a diagram showing an execution status of a motor stop mode. [Figure 14B] FIG. 13 is a diagram showing the state in which the all-wheel drive mode is being executed. [Figure 15] FIG. 4 is a collinear diagram showing a transition of an operating state of a center differential during driving mode switching control. [Figure 16A] 4 is a timing chart showing an example of an execution state of a driving mode switching control as an embodiment. [Figure 16B] 5 is a timing chart showing an example of an execution state of driving mode switching control as a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or substantially same configurations and elements will be designated by the same reference numerals and will not be described repeatedly.

[0010] [Overall configuration of vehicle control device] Fig. 1 is a diagram showing an example of the configuration of a vehicle 11 equipped with a vehicle control device 10 according to an embodiment of the present invention. As shown in Fig. 1, the vehicle 11 is equipped with a power unit 14 equipped with an engine 12 and a transmission 13. In addition, rear wheels 18 are connected to an output shaft 15 of the power unit 14 via a propeller shaft 16 and a rear drive unit 17. Furthermore, a front differential 19 is incorporated in the transmission 13, and front wheels 20 are connected to the front differential 19.

[0011] Fig. 2 is a diagram showing an example of the configuration of the power unit 14 and the rear drive unit 17. As shown in Fig. 2, the power unit 14 is provided with a center differential 22 equipped with a planetary gear mechanism 21. The rear wheels 18 are connected to the center differential 22 via a rear wheel drive path 23, and the front wheels 20 are connected to the center differential 22 via a front wheel drive path 24. In addition, the engine 12 is connected to the center differential 22 via a power transmission path 25. In this way, the engine 12, the front wheels 20, and the rear wheels 18 are connected to each other via the center differential 22.

[0012] [Power unit] The configuration of the power unit 14 will be described. As described above, the power unit 14 is provided with a center differential 22 equipped with a planetary gear mechanism 21. The planetary gear mechanism 21 has a ring gear R also called an internal gear, a carrier C that rotatably supports a pinion P that meshes with the ring gear R, and a sun gear S that meshes with the pinion P. The center differential 22 is also provided with a differential limiting clutch 26 that fastens the ring gear R and the carrier C to each other.

[0013] The ring gear (first rotating element) R of the center differential 22 is connected to the rear wheels (first wheels) 18 via a rear-wheel drive path (first path) 23. Furthermore, the sun gear (second rotating element) S of the center differential 22 is connected to the front wheels (second wheels) 20 via a front-wheel drive path (second path) 24. Furthermore, the engine 12 is connected to the carrier (third rotating element) C of the center differential 22 via a power transmission path (third path) 25.

[0014] A torque converter 30, a forward / reverse switching mechanism 31, and a speed change mechanism 32 are provided between the engine 12 and the center differential 22. In other words, the engine 12 and the center differential 22 are connected via a power transmission path 25 consisting of the torque converter 30, the forward / reverse switching mechanism 31, the speed change mechanism 32, etc. A forward / reverse switching mechanism 31 that switches the rotation direction of a carrier 34c is connected to the torque converter 30 that is connected to a crankshaft 33 of the engine 12. The forward / reverse switching mechanism 31 has a double pinion type planetary gear train 34, a forward clutch 35 that fastens the sun gear 34s and the carrier 34c of the planetary gear train 34 to each other, and a reverse brake 37 that fixes the ring gear 34r of the planetary gear train 34 to a transmission case 36.

[0015] During forward travel, the forward clutch 35 is engaged and the reverse brake 37 is released. This allows the rotational directions of the input side sun gear 34s and the output side carrier 34c to coincide with each other, allowing the transmission mechanism 32 to rotate in the rotational direction during forward travel. On the other hand, during reverse travel, the reverse brake 37 is engaged and the forward clutch 35 is released. This allows the rotational directions of the input side sun gear 34s and the output side carrier 34c to be reversed from each other, allowing the transmission mechanism 32 to rotate in the rotational direction during reverse travel.

[0016] The speed change mechanism 32 has a primary pulley 41 supported by a primary shaft 40 and a secondary pulley 43 supported by a secondary shaft 42. A primary oil chamber 41a is provided in the primary pulley 41, and a secondary oil chamber 43a is provided in the secondary pulley 43. A drive chain 44 is wound around the primary pulley 41 and the secondary pulley 43. In this speed change mechanism 32, the winding diameter of the drive chain 44 can be changed by adjusting the hydraulic pressure in the primary oil chamber 41a and the secondary oil chamber 43a, thereby enabling infinitely variable speed change from the primary shaft 40 to the secondary shaft 42. A carrier C, which is an input element of the center differential 22, is connected to the secondary shaft 42 of the speed change mechanism 32.

[0017] In addition, a gear train 50 and a front differential 19 are provided between the center differential 22 and the front wheels 20. In other words, the center differential 22 and the front wheels 20 are connected via a front wheel drive path 24 consisting of the gear train 50, the front differential 19, etc. That is, a drive gear 50a is connected to a sun gear S, which is an output element of the center differential 22, and a front wheel drive shaft 51 is connected to a driven gear 50b meshing with the drive gear 50a. A pinion 52 is provided at the tip of the front wheel drive shaft 51, and a bevel gear 54 fixed to a differential case 53 of the front differential 19 is meshed with the pinion 52. The front wheels 20 are connected to a front shaft 55 extending from the front differential 19. The pinion 52 and the bevel gear 54, which mesh with each other, are configured as a spiral bevel gear or a hypoid (registered trademark) gear having curved teeth.

[0018] [Rear drive unit] The configuration of the rear drive unit 17 will be described. The rear drive unit 17 is connected to the output shaft 15 connected to the ring gear R, which is the output element of the center differential 22, that is, the output shaft 15 of the power unit 14, via the propeller shaft 16. A motor generator 60 and a rear differential 61 are incorporated in the rear drive unit 17. A bevel gear 63 is provided on a rotor shaft 62 of the motor generator 60, and a pinion 64 connected to the propeller shaft 16 is meshed with the bevel gear 63. The pinion 64 and the bevel gear 63 mesh with each other and are configured as a spiral bevel gear or a hypoid (registered trademark) gear having curved teeth. A drive gear 66 is connected to the rotor shaft 62 of the motor generator 60 via a rear clutch (wheel drive clutch) 65. Furthermore, a driven gear 68 fixed to a differential case 67 of the rear differential 61 is meshed with the drive gear 66. The rear wheels 18 are connected to a rear shaft 69 extending from the rear differential 61 .

[0019] In this manner, the center differential 22 and the rear wheels 18 are connected via a rear wheel drive path 23 that includes the propeller shaft 16 and the rear drive unit 17. The rear wheel drive path 23 that connects the center differential 22 and the rear wheels 18 is provided with a motor generator 60 and a rear clutch 65. The rear clutch 65 is located between the motor generator 60 and the rear wheels 18. By controlling the rear clutch 65 to a released state, the rear wheels 18 can be disconnected from the pinion shaft and the rotor shaft 62, and the engine 12 and the motor generator 60 can be disconnected from the rear wheels 18. On the other hand, by controlling the rear clutch 65 to an engaged state, the rear wheels 18 can be connected to the pinion shaft and the rotor shaft 62, and the rear wheels 18 can be connected to the engine 12 and the motor generator 60.

[0020] [Control System] FIG. 3 is a diagram showing an example of the power unit 14, the rear drive unit 17, and the control system 70. As shown in FIG. 3, the vehicle control device 10 is provided with a control system 70 consisting of a plurality of electronic control units in order to control the power unit 14, the rear drive unit 17, and the like. As electronic control units constituting the control system 70, an engine control unit (ECU: Engine Control Unit) 71 and a transmission control unit (TCU: Transmission Control Unit) 72 are provided. As electronic control units constituting the control system 70, a motor control unit (MCU: Motor Control Unit) 73 and a battery control unit (BCU: Battery Control Unit) 74 are provided. Furthermore, as electronic control units constituting the control system 70, a vehicle control unit (VCU: Vehicle Control Unit) 75 that outputs control signals to the control units 71 to 74 is provided.

[0021] These control units 71-75 are connected to each other so as to be able to communicate with each other via an in-vehicle network 76 such as CAN or LIN. The vehicle control unit 75 sets operation targets for the engine 12, the motor generator 60, the transmission mechanism 32, the limited differential clutch 26, the rear clutch 65, etc., based on input information from the various control units 71-74 and various sensors described below. Then, the vehicle control unit 75 generates control signals according to the operation targets for the engine 12, the motor generator 60, etc., and outputs these control signals to the various control units 71-74.

[0022] Sensors connected to the vehicle control unit 75 include a vehicle speed sensor 77 that detects the vehicle speed, which is the traveling speed of the vehicle 11, an accelerator sensor 78 that detects the amount of accelerator pedal operation (hereinafter referred to as accelerator opening), and a brake sensor 79 that detects the amount of brake pedal operation. Sensors connected to the vehicle control unit 75 include a wheel speed sensor 80 that detects the rotation speed of the front wheels 20 and the rear wheels 18, and a steering angle sensor 81 that detects the steering angle of the steering operated by the driver. A start switch 82 that is operated by the driver when starting up the control system 70 is connected to the vehicle control unit 75.

[0023] Also connected to the transmission control unit 72 are a primary rotation sensor 83 which detects the rotation speed of the primary pulley 41, and a secondary rotation sensor 84 which detects the rotation speed of the secondary pulley 43. Furthermore, connected to the motor control unit 73 is a motor rotation sensor 85 which detects the rotation speed of the rotor 60r of the motor generator 60 (hereinafter referred to as the motor rotation speed). Furthermore, connected to the battery control unit 74 is a battery sensor 86 which detects the charge / discharge current, terminal voltage, temperature, etc. of the battery 93 which will be described later.

[0024] Furthermore, in order to control hydraulic devices such as the forward / reverse switching mechanism 31, the transmission mechanism 32, the limited slip clutch 26, and the rear clutch 65, the vehicle 11 is provided with a valve unit 90 consisting of a plurality of electromagnetic valves, oil passages, and the like. Furthermore, an oil pump 91 driven by the engine 12 or the like is connected to the valve unit 90. The hydraulic oil discharged from the oil pump 91 is supplied to the hydraulic devices such as the limited slip clutch 26 and the rear clutch 65, with the supply destination, pressure, and the like being controlled by the valve unit 90. In order to control hydraulic devices such as the limited slip clutch 26 and the rear clutch 65 via this valve unit 90, the transmission control unit 72 outputs a control signal to the valve unit 90.

[0025] A battery (electricity storage device) 93 such as a lithium ion battery is connected to the stator 60s of the motor generator 60 via an inverter 92. A motor control unit 73 that controls the motor generator 60 outputs a control signal to the inverter 92, which is a power conversion device. A battery control unit 74 that monitors the charge and discharge status of the battery 93 has a function of calculating a state of charge (SOC) of the battery 93 based on a charge and discharge current detected by a battery sensor 86. The SOC of the battery 93 is a ratio indicating the remaining amount of electricity in the battery 93, and is a ratio of the amount of stored electricity to the full charge capacity of the battery 93. For example, when the battery 93 is charged to an upper limit capacity, the SOC is calculated as 100%, and when the battery 93 is discharged to a lower limit capacity, the SOC is calculated as 0%. An engine control unit 71 that controls the engine 12 outputs a control signal to an auxiliary device 94 such as a throttle valve and an injector.

[0026] Fig. 4 is a diagram simply illustrating the basic structure of each of the control units 71 to 75. As shown in Fig. 4, each of the control units 71 to 75 has a microcontroller 102 incorporating a processor 100, a memory 101, and the like. A predetermined program is stored in the memory 101, and an instruction set of the program is executed by the processor 100. The processor 100 and the memory 101 are connected to each other so as to be able to communicate with each other. In the illustrated example, one processor 100 and one memory 101 are incorporated in the microcontroller 102, but this is not limited thereto, and a plurality of processors 100 may be incorporated in the microcontroller 102, and a plurality of memories 101 may be incorporated in the microcontroller 102.

[0027] Each of the control units 71 to 75 is provided with an input conversion circuit 103, a drive circuit 104, a communication circuit 105, an external memory 106, a power supply circuit 107, and the like. The input conversion circuit 103 converts signals input from various sensors into signals that can be input to the microcontroller 102. The drive circuit 104 generates drive signals for actuators such as the valve unit 90 described above based on signals output from the microcontroller 102. The communication circuit 105 converts signals output from the microcontroller 102 into communication signals directed to other control units. The communication circuit 105 also converts communication signals received from other control units into signals that can be input to the microcontroller 102. The power supply circuit 107 supplies a stable power supply voltage to the microcontroller 102, the input conversion circuit 103, the drive circuit 104, the communication circuit 105, the external memory 106, and the like. The external memory 106, such as a non-volatile memory, stores data that should be retained even when power is not applied.

[0028] [Driving mode] Next, the driving modes of the vehicle 11 will be described. Fig. 5A is a diagram showing the execution status of the all-wheel drive mode and the all-wheel regeneration mode, Fig. 5B is a diagram showing the execution status of the front-wheel regeneration mode, and Fig. 5C is a diagram showing the execution status of the motor stop mode. As will be described later, the control system 70 has the all-wheel drive mode, the all-wheel regeneration mode, the front-wheel regeneration mode, and the motor stop mode as driving modes when the vehicle 11 is driven.

[0029] As shown in FIG. 5A, when the all-wheel drive mode or the all-wheel regeneration mode is executed, the differential limiting clutch 26 is controlled to a released state, and the rear clutch 65 is controlled to an engaged state. As a result, the engine 12, the motor generator 60, the front wheels 20, and the rear wheels 18 are connected to each other via the center differential 22. That is, in the all-wheel drive mode executed during acceleration driving or steady driving, the differential limiting clutch 26 is controlled to a released state, the rear clutch 65 is controlled to an engaged state, and the motor generator 60 is controlled to a powering state. As a result, the driving force output from the engine 12 and the motor generator 60 can be distributed to both the front wheels 20 and the rear wheels 18. Furthermore, in the all-wheel drive mode, the driving force distribution ratio of the front and rear wheels 18, 20 can be freely adjusted by controlling the powering torque of the motor generator 60. In the illustrated example, the differential limiting clutch 26 is controlled to a released state, but this is not limited thereto, and the differential limiting clutch 26 may be controlled to an engaged state.

[0030] In the all-wheel regeneration mode executed during deceleration, the limited slip clutch 26 is controlled to a released state, the rear clutch 65 is controlled to an engaged state, and the motor generator 60 is controlled to a regenerative state. This allows the braking force generated in the engine 12 and the motor generator 60 to be distributed to both the front wheels 20 and the rear wheels 18. Furthermore, in the all-wheel regeneration mode, the braking force distribution ratio of the front and rear wheels 18, 20 can be freely adjusted by controlling the regenerative torque of the motor generator 60. In the illustrated example, the limited slip clutch 26 is controlled to a released state, but this is not limiting and the limited slip clutch 26 may be controlled to an engaged state.

[0031] 5B, when the front wheel regeneration mode (motor regeneration mode) is executed, the differential limiting clutch 26 is controlled to an engaged state, the rear clutch 65 is controlled to a released state, and the motor generator 60 is controlled to a regenerative state. This allows the motor generator 60 to be disconnected from the rear wheels 18 and connected to the front wheels 20. In other words, since the motor generator 60 can be directly connected to the front wheels 20, which can easily increase the braking force, the regenerative torque of the motor generator 60 can be significantly increased, and the energy efficiency of the vehicle 11 can be improved.

[0032] Also, as shown in FIG. 5C, when the motor stop mode is executed, the differential limiting clutch 26 is controlled to be in a released state, the rear clutch 65 is controlled to be in a released state, and the motor generator 60 is controlled to be in a rotation stop state. That is, since the rear clutch 65 is released, the rear wheels 18 can be separated from the motor generator 60. Also, since the differential limiting clutch 26 is released, the motor generator 60 can be stopped while the front wheels 20 are rotating. As a result, the rotation of the propeller shaft 16, the pinion 64, the bevel gear 63, and the rotor 60r can be stopped while the vehicle is traveling. That is, the rotation resistance of the rear wheel drive path 23 can be reduced, and the energy efficiency of the vehicle 11 can be improved. The rotation stop state of the motor generator 60 is a state in which the motor torque is controlled so as to maintain the motor rotation speed at zero.

[0033] [Driving mode setting control 1] A driving mode setting control 1 for setting a driving mode during deceleration driving will be described. FIG. 6 is a flowchart showing an example of an execution procedure of the driving mode setting control 1. Each step shown in the flowchart of FIG. 6 shows a process executed by one or more processors 100 constituting the control system 70. The driving mode setting control 1 shown in FIG. 6 is a control executed by the control system 70 at predetermined intervals after the driver operates the start switch 82 and the control system 70 consisting of the vehicle control unit 75 and the like is started. FIG. 7A is a diagram showing an execution state of the motor stop mode during coasting, and FIG. 7B is a collinear diagram showing the operating state of the center differential 22 shown in FIG. 7A. Furthermore, FIG. 8 is a diagram showing an execution state of the front wheel regeneration mode during coasting. Note that torque flows are shown by arrows in FIG. 7A and FIG. 8.

[0034] 6, in step S10, it is determined whether or not the preconditions for the driving mode setting control 1 are satisfied. Here, the preconditions for the driving mode setting control 1 include that the control system 70 is functioning normally and that the regenerative operation of the motor generator 60 is permitted. That is, in step S10, if the control system 70 is functioning normally and the regenerative operation of the motor generator 60 is permitted, it is determined that the preconditions are satisfied, and the process proceeds to the next step S11.

[0035] In step S11, it is determined whether the vehicle 11 is in a coasting state. That is, if it is determined in step S11 that the driver has released the accelerator pedal and the brake pedal, it is determined that the vehicle 11 is in a coasting state, which gradually decelerates the vehicle 11. If it is determined in step S11 that the vehicle is in a coasting state, the process proceeds to step S12, where it is determined whether the SOC of the battery 93 exceeds a predetermined threshold value S1 (for example, 95%).

[0036] If it is determined in step S12 that the SOC of the battery 93 exceeds the threshold value S1, energy regeneration by the motor generator 60 is difficult, so the process proceeds to step S13, and a motor stop mode is executed to stop the rotation of the motor generator 60. That is, as shown in FIG. 7A, the control system 70 controls the limited differential clutch 26 to a released state, controls the rear clutch 65 to a released state, and controls the motor generator 60 to a rotation stop state. This makes it possible to stop the rotation of the propeller shaft 16, the pinion 64, the bevel gear 63, and the rotor 60r during coasting in which the vehicle 11 is decelerating slowly. That is, the rotational resistance and the oil agitation resistance of the rear wheel drive path 23 can be reduced, so that the travel distance by coasting can be extended and the energy efficiency of the vehicle 11 can be improved.

[0037] 7B, by executing the motor stop mode during coasting, the rotation of the motor generator 60 can be stopped (symbol A1), and the rotation speed of the carrier C can be reduced (arrow A2) while maintaining the vehicle speed. This reduces the rotation speed of the power transmission path 25, which includes the transmission mechanism 32 and the like, and reduces the rotational resistance and oil agitation resistance of the power transmission path 25, thereby extending the travel distance during coasting and improving the energy efficiency of the vehicle 11. Furthermore, because the motor generator 60 is controlled to a rotation stop state, it is possible to avoid field weakening control of the motor generator 60, and this also improves the energy efficiency of the vehicle 11.

[0038] 6, when it is determined that the SOC of the battery 93 is equal to or lower than the threshold value S1, energy regeneration by the motor generator 60 is required, and the process proceeds to step S14, where a front wheel regeneration mode in which the front wheels 20 are directly connected to the motor generator 60 is executed. That is, as shown in FIG. 8, the control system 70 controls the limited slip clutch 26 to an engaged state, controls the rear clutch 65 to a released state, and controls the motor generator 60 to a regenerative state. This allows the motor generator 60 to actively regenerate during coasting in which the vehicle 11 is decelerating slowly, and the energy efficiency of the vehicle 11 can be improved. In the example shown in FIG. 8, a part of the power input from the front wheels 20 is transmitted from the center differential 22 to the engine 12.

[0039] In the above description, when it is determined that the SOC of the battery 93 is equal to or lower than the threshold value S1 during coasting, the front wheel regeneration mode is executed as the driving mode, but this is not limited to this. For example, when it is determined that the SOC of the battery 93 is equal to or lower than the threshold value S1 during coasting, the all-wheel regeneration mode may be executed as the driving mode. Here, FIG. 9 is a diagram showing the execution status of the all-wheel regeneration mode during coasting. Note that FIG. 9 shows torque flow using arrows.

[0040] As shown in Fig. 9, when it is determined that the SOC of the battery 93 is equal to or lower than the threshold value S1 during coasting, the all-wheel regeneration mode may be executed as the driving mode. That is, as shown in Fig. 9, the control system 70 controls the differential limiting clutch 26 to a released state, controls the rear clutch 65 to an engaged state, and controls the motor generator 60 to a regenerative state. As a result, even when the motor generator 60 is regenerated during coasting, the braking force can be distributed to the front wheels 20 and the rear wheels 18, so that coasting can be stabilized even on a slippery road surface such as a snowy road. In the example shown in Fig. 9, the differential limiting clutch 26 is controlled to a released state, but the present invention is not limited to this, and the differential limiting clutch 26 may be controlled to an engaged state.

[0041] [Driving mode setting control 2] Next, the driving mode setting control 2 for setting the driving mode during acceleration driving or steady driving will be described. FIG. 10 is a flowchart showing an example of the execution procedure of the driving mode setting control 2. Each step shown in the flowchart of FIG. 10 shows processing executed by one or more processors 100 constituting the control system 70. The driving mode setting control 2 shown in FIG. 10 is a control executed by the control system 70 at predetermined intervals after the driver operates the start switch 82 and the control system 70 consisting of the vehicle control unit 75 and the like is started. FIG. 11A is a diagram showing the execution status of the motor stop mode during high-speed driving, and FIG. 11B is a collinear diagram showing the operating state of the center differential 22 shown in FIG. 11A. Furthermore, FIG. 12 is a diagram showing the execution status of the all-wheel drive mode during high-speed driving. Note that torque flow is shown by arrows in FIG. 11A and FIG. 12.

[0042] 10, in step S20, it is determined whether or not the preconditions for the traveling mode setting control 2 are satisfied. Here, the preconditions for the traveling mode setting control 2 include that the control system 70 is functioning normally and that the powering operation of the motor generator 60 is permitted. That is, in step S20, if the control system 70 is functioning normally and the powering operation of the motor generator 60 is permitted, it is determined that the preconditions are satisfied, and the process proceeds to the next step S21.

[0043] In step S21, it is determined whether or not the accelerator pedal is being operated by the driver. If it is determined in step S21 that the accelerator pedal is being operated, that is, if it is determined that the vehicle 11 is accelerating or running steadily, the process proceeds to step S22, where it is determined whether or not the vehicle speed exceeds a predetermined threshold value V1. If it is determined in step S22 that the vehicle speed is high-speed running and exceeds threshold value V1, the energy efficiency of motor generator 60 is likely to decrease, so the process proceeds to step S23, where a motor stop mode is executed to stop the rotation of motor generator 60.

[0044] That is, as shown in FIG. 11A, the control system 70 controls the differential limiting clutch 26 to a released state, controls the rear clutch 65 to a released state, and controls the motor generator 60 to a rotation stop state. As a result, during high-speed running where the vehicle speed exceeds the threshold value V1, the rotation of the motor generator 60 can be stopped, and the field weakening control for maintaining the high-speed rotation of the motor generator 60 can be avoided. As a result, the energy loss of the motor generator 60 can be reduced, and the energy efficiency of the vehicle 11 can be improved. Also, during high-speed running where the vehicle speed exceeds the threshold value V1, the rotation of the propeller shaft 16, the pinion 64, the bevel gear 63, and the rotor 60r can be stopped. That is, since the rotational resistance and the oil stirring resistance of the rear wheel drive path 23 can be reduced, the energy efficiency of the vehicle 11 during high-speed running can be improved.

[0045] 11B, by executing the motor stop mode during high-speed driving, the rotation of the motor generator 60 can be stopped (symbol B1), and the rotation speed of the carrier C can be reduced (arrow B2) while maintaining the vehicle speed. This allows the rotation speed of the power transmission path 25, which includes the transmission mechanism 32 and the like, to be reduced, and the rotational resistance and oil agitation resistance of the power transmission path 25 can be reduced, thereby improving the energy efficiency of the vehicle 11 during high-speed driving.

[0046] 10, if it is determined that the vehicle speed is equal to or lower than the threshold value V1, the energy efficiency of the motor generator 60 is not significantly reduced, so the process proceeds to step S24, and the all-wheel drive mode in which both the front wheels 20 and the rear wheels 18 are driven is executed. That is, as shown in FIG 12, the control system 70 controls the limited slippery differential clutch 26 to a released state, controls the rear clutch 65 to an engaged state, and controls the motor generator 60 to a powering state. This allows the driving force to be distributed to the front wheels 20 and the rear wheels 18, so that the posture of the vehicle 11 can be stabilized even on a slippery road surface such as a snowy road.

[0047] In the example shown in Fig. 12, the differential limiting clutch 26 is controlled to a released state, but this is not limited thereto, and the differential limiting clutch 26 may be controlled to an engaged state. In addition, in the example shown in Fig. 12, the motor generator 60 is controlled to a powering state, but this is not limited thereto. In other words, when the engine 12 torque is large, the accelerator opening is small, the SOC is low, etc., the motor generator 60 may be controlled to a regenerative state even in an all-wheel drive mode for accelerating or steady driving.

[0048] [Driving mode switching control] Hereinafter, a description will be given of a driving mode switching control for switching the driving mode from the motor stop mode to the all-wheel drive mode. FIG. 13 is a flowchart showing an example of a procedure for executing the driving mode switching control. Each step shown in the flowchart of FIG. 13 shows a process executed by one or more processors 100 constituting the control system 70. The driving mode switching control shown in FIG. 13 is a control executed by the control system 70 during the motor stop mode. FIG. 14A is a diagram showing an execution state of the motor stop mode, and FIG. 14B is a diagram showing an execution state of the all-wheel drive mode. Furthermore, FIG. 15 is a collinear diagram showing a transition of the operating state of the center differential 22 in the driving mode switching control. Note that torque flows are shown by arrows in FIG. 14A and FIG. 14B.

[0049] As shown in Fig. 13, in step S30, the motor stop mode is executed as the driving mode. That is, as shown in Fig. 14A, the control system 70 controls the limited differential clutch 26 to a released state, controls the rear clutch 65 to a released state, and controls the motor generator 60 to a rotation stop state. Next, as shown in Fig. 13, in step S31, it is determined whether or not the all-wheel drive request flag is set based on the driving situation, traveling situation, etc.

[0050] Here, the all-wheel drive request flag is a flag that is set when the driving mode is switched from the motor stop mode to the all-wheel drive mode. For example, when the accelerator opening exceeds a predetermined threshold, when the steering angle exceeds a predetermined threshold, or when the slip ratio of each wheel exceeds a predetermined threshold, the all-wheel drive request flag is set from the viewpoint of stabilizing vehicle driving. On the other hand, when the accelerator opening falls below the predetermined threshold, the steering angle falls below the predetermined threshold, and the slip ratio of each wheel falls below the predetermined threshold, the vehicle driving is stable and the all-wheel drive request flag is released.

[0051] If it is determined in step S31 that the all-wheel drive request flag is set, the process proceeds to step S32, where switching from the motor stop mode to the all-wheel drive mode is started. Here, as shown in FIG. 14A and FIG. 14B, in order to switch from the motor stop mode to the all-wheel drive mode, it is necessary to switch the rear clutch 65 from a released state to an engaged state. For this reason, it is required to rotate the stopped propeller shaft 16 and the rotor shaft 62 by controlling the motor generator 60 to a power running state, thereby eliminating the rotation speed difference before and after the rear clutch 65. That is, as shown in FIG. 15, when the rotation speed of the sun gear S during traveling is "N1", it is necessary to increase the motor rotation speed until the rotation speed of the ring gear R reaches "N1", as shown by the arrow C1. In the example shown in FIG. 15, the gear ratio of the front wheel drive path 24 and the gear ratio of the rear wheel drive path 23 are mutually matched. That is, the situation in which the rotation speeds of the ring gear R and the sun gear S are mutually matched is the situation in which the rotation speeds of the front wheels 20 and the rear wheels 18 are mutually matched.

[0052] When the motor rotation speed is increased in this manner, as shown by the arrow C2 in FIG. 15, the motor generator 60 increases the rotation speed of the carrier C, and the rotation speed of the crankshaft 33 (hereinafter referred to as the engine rotation speed) is also increased via the power transmission path 25. However, excessive changes in the engine rotation speed when switching the driving mode can cause the driver to feel uncomfortable. Therefore, in step S32 in FIG. 13, the control system 70 increases the motor rotation speed and executes an upshift of the transmission mechanism 32. Then, in step S33, it is determined whether the rotation speed difference ΔN before and after the rear clutch 65 is below a predetermined threshold value Nx (for example, 100 rpm). If it is determined in step S33 that the rotation speed difference ΔN is below the threshold value Nx, the rotation speed difference before and after the rear clutch 65 has been eliminated, so the process proceeds to step S34, where the rear clutch 65 is controlled to be in an engaged state, and the transition from the motor stop mode to the all-wheel drive mode is completed. The rotational speed difference ΔN before and after the rear clutch 65 is the rotational speed difference between the rotor shaft 62 and the drive gear 66 .

[0053] 16A is a timing chart showing an example of the execution state of the traveling mode switching control as an embodiment, and FIG. 16B is a timing chart showing an example of the execution state of the traveling mode switching control as a comparative example. In FIG. 16A and FIG. 16B, "Ne" is the engine rotation speed, "Nc" is the rotation speed of the carrier C linked to the motor rotation speed, and "Rg" is the gear ratio of the transmission mechanism 32.

[0054] As shown in FIG. 16A, when the switching from the motor stop mode to the all-wheel drive mode starts at time t1, the rotation speed Nc of the carrier C increases from N2 to N1 due to the increase in the motor rotation speed (symbol a1). At this time, the transmission mechanism 32 is upshifted, and the gear ratio Rg of the transmission mechanism 32 changes to the high side (symbol b1). In this way, by performing the upshift of the transmission mechanism 32, the increase in the engine rotation speed Ne accompanying the increase in the carrier C can be suppressed (symbol c1). Then, as shown at time t2, when the rotation speed Nc of the carrier C reaches N1 (symbol a2), the difference in rotation speed between the front and rear of the rear clutch 65 is eliminated, and the rear clutch 65 is engaged, completing the switching to the all-wheel drive mode. In this way, by performing the upshift of the transmission mechanism 32, the excessive increase in the engine rotation speed Ne can be suppressed, and the driving mode can be switched without giving a sense of discomfort to the driver. In the example shown in FIG. 16A, the engine rotation speed Ne is kept constant, but this is not limiting and the engine rotation speed Ne may be increased or decreased within a range that does not cause discomfort to the driver.

[0055] On the other hand, as shown in FIG. 16B, when the motor stop mode is switched to the all-wheel drive mode at time t1, the rotation speed Nc of the carrier C increases from N2 to N1 due to the increase in the motor rotation speed (symbol d1). At this time, if the speed ratio Rg of the transmission mechanism 32 is maintained (symbol e1), the engine rotation speed Ne increases with the increase in the carrier C (symbol f1). The increase in the engine rotation speed Ne continues until the rotation speed Nc of the carrier C reaches N1. In this way, if the speed ratio Rg of the transmission mechanism 32 is maintained, the engine rotation speed Ne may increase excessively, causing the driver to feel uncomfortable. In response to this, as shown in FIG. 16A, the transmission mechanism 32 is upshifted to suppress the excessive increase in the engine rotation speed Ne.

[0056] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the gist of the present invention. In the above description, the control system 70 is configured by a plurality of control units 71 to 75, but the present invention is not limited to this. For example, the control system 70 may be configured by one control unit. In the above description, a continuously variable transmission is used as the transmission mechanism 32, but the present invention is not limited to this, and a planetary gear type automatic transmission may be used as the transmission mechanism 32. In the above description, the ring gear R is connected to the rear wheel 18, and the sun gear S is connected to the front wheel 20, but the present invention is not limited to this, and the ring gear R may be connected to the front wheel 20, and the sun gear S may be connected to the rear wheel 18. That is, the ring gear R is used as the first rotating element, and the sun gear S is used as the second rotating element, but the present invention is not limited to this, and the sun gear S may be used as the first rotating element, and the ring gear R may be used as the second rotating element. In addition, in the illustrated example, a single-pinion type planetary gear mechanism is used as the planetary gear mechanism 21, but this is not limited thereto, and other types of planetary gear mechanisms may be used. In this way, even when other types of planetary gear mechanisms are used, it is possible to use the rotating elements located at both ends on the collinear diagram as the first rotating element and the second rotating element.

[0057] In the above description, the limited slip differential clutch 26 and the rear clutch 65 are hydraulic clutches, but the present invention is not limited to this. For example, the limited slip differential clutch 26 and the rear clutch 65 may be controlled by an electric actuator or the like. In addition, the limited slip differential clutch 26 and the rear clutch 65 are friction clutches, but the present invention is not limited to this, and the limited slip differential clutch 26 and the rear clutch 65 may be mesh clutches. In addition, the limited slip differential clutch 26 fastens the ring gear R and the carrier C to each other, but the present invention is not limited to this, and it is sufficient that at least two of the ring gear R, the carrier C, and the sun gear S are fastened.

[0058] In the above description, the rear wheels 18 are used as the first wheels and the front wheels 20 are used as the second wheels, but the present invention is not limited thereto. The front wheels 20 may be used as the first wheels and the rear wheels 18 may be used as the second wheels. In this case, the front wheels 20 are disconnected from the motor generator 60 and the engine 12 in the motor stop mode. In addition, in the flowchart shown in FIG. 6, the motor stop mode is executed when the SOC of the battery 93 exceeds the threshold value S1 during coasting, but the present invention is not limited thereto. For example, when the vehicle 11 is decelerated with the brake pedal depressed, if the SOC of the battery 93 falls below the threshold value S1, the differential limiting clutch 26 and the rear clutch 65 may be released and the motor generator 60 may be controlled to a rotation stop state to execute the motor stop mode. [Explanation of symbols]

[0059] 10 Vehicle control device 11 Vehicles 12 Engine 18 Rear wheel (1st wheel) 20 Front wheel (2nd wheel) 21 Planetary gear mechanism 23 Rear wheel drive path (first path) 24 Front wheel drive path (second path) 25 Power transmission path (third path) 26 Limited slip differential clutch 32 Transmission mechanism 60 Motor Generator 65 Rear clutch (wheel drive clutch) 70 Control System 93 Battery (energy storage device) 100 processors 101 Memory R Ring gear (first rotating element) S Sun gear (second rotating element) C Carrier (third rotating element) S1 Threshold V1 Threshold

Claims

1. A vehicle control device that controls a vehicle, a planetary gear mechanism including a first rotating element, a second rotating element, and a third rotating element; a first wheel coupled to the first rotating element via a first path; a second wheel coupled to the second rotating element via a second path; an engine connected to the third rotating element via a third path; a motor generator provided in the first path; a wheel drive clutch provided in the first path and positioned between the motor generator and the first wheel; an electricity storage device connected to the motor generator; a differential limiting clutch that engages at least two of the first rotating element, the second rotating element, and the third rotating element; a control system including a processor and a memory communicatively connected to each other, the control system controlling the motor generator, the wheel drive clutch, and the limited slip differential clutch; having the control system has a motor stop mode in which the differential limiting clutch is controlled to a released state, the wheel drive clutch is controlled to a released state, and the motor generator is controlled to a rotation stop state; the control system has a motor regeneration mode in which the differential limiting clutch is controlled to an engaged state, the wheel drive clutch is controlled to a released state, and the motor generator is controlled to a regeneration state; The control system executes the motor stop mode when the vehicle is decelerating and the SOC of the power storage device exceeds a threshold value. The control system executes the motor regeneration mode when the vehicle is decelerating and the SOC of the power storage device falls below the threshold value. Vehicle control device.

2. 2. The vehicle control device according to claim 1, The control system executes the motor stop mode when the vehicle speed exceeds a threshold. Vehicle control device.

3. 3. The vehicle control device according to claim 1, A speed change mechanism is provided in the third path, the control system has an all-wheel drive mode in which the wheel drive clutch is controlled to an engaged state and the motor generator is controlled to a powering state; the control system executes an upshift of the transmission mechanism when switching from the motor stop mode to the all-wheel drive mode. Vehicle control device.

4. A vehicle control device that controls a vehicle, a planetary gear mechanism including a first rotating element, a second rotating element, and a third rotating element; a first wheel coupled to the first rotating element via a first path; a second wheel coupled to the second rotating element via a second path; an engine connected to the third rotating element via a third path; a motor generator provided in the first path; a wheel drive clutch provided in the first path and positioned between the motor generator and the first wheel; A speed change mechanism provided in the third path; a control system including a processor and a memory communicatively connected to each other, the control system controlling the motor generator, the wheel drive clutch, and the transmission mechanism; having the control system has a motor stop mode in which the wheel drive clutch is controlled to a released state and the motor generator is controlled to a rotation stopped state; the control system has an all-wheel drive mode in which the wheel drive clutch is controlled to an engaged state and the motor generator is controlled to a powering state; the control system executes an upshift of the transmission mechanism when switching from the motor stop mode to the all-wheel drive mode. Vehicle control device.

Images