Control device for hybrid vehicle

Abstract

The present invention relates to a control device for a hybrid vehicle. When the all-wheel drive mode is selected, it is not easy to cause discomfort to the driver. When the all-wheel drive mode is selected in the main drive wheel drive mode when the engine is in a stopped state, the stopped state of the engine is maintained before the switch from the main drive wheel drive mode to the all-wheel drive mode is completed, and the engine is started after the driver performs a predetermined operation for driving the hybrid vehicle, thereby avoiding the switching to the all-wheel drive mode and the engine starting at the same time, preventing the occurrence of shock, and further, starting the engine based on the driver's operation associated with the engine start. As a result, when the all-wheel drive mode is selected, it is not easy to cause discomfort to the driver.

Description

Technical Field

[0001] The present invention relates to a control device for a hybrid vehicle including an engine and an electric motor. Background Art

[0002] A control device for a hybrid vehicle is known, which includes an engine, an electric motor, and a driving force distribution device that distributes driving force to a main driving wheel and a secondary driving wheel. For example, the driving device of a hybrid vehicle described in Patent Document 1 is such a device. Patent Document 1 discloses a driving mode selected by a driver, which includes a first mode and a second mode in which power performance is given more importance than energy efficiency compared to the first mode. In addition, when the driver selects the second mode, the engine is started when the engine is in a stopped state. In addition, Patent Document 1 exemplifies a transfer case low driving mode in which the transmission in the transfer case as a driving force distribution device is set to a low gear and the vehicle is driven as the second mode.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-179780 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In addition, it is also known that there are vehicles having a main drive wheel drive mode in which driving force is distributed only to the main drive wheel and a full-wheel drive mode in which driving force is distributed to both the main drive wheel and the auxiliary drive wheel as a driving mode. In such a vehicle, in the full-wheel drive mode, power performance is more likely to be valued than energy efficiency compared to the main drive wheel drive mode. Therefore, it is considered that when the engine is in a stopped state, when switching from the main drive wheel drive mode to the full-wheel drive mode, the engine is started. However, when the driver chooses to switch from the main drive wheel drive mode to the full-wheel drive mode, it is possible that the driver does not necessarily intend to start the engine. Therefore, if the engine is started immediately when the full-wheel drive mode is selected, it is possible to cause discomfort to the driver. Alternatively, if the engine is started immediately when the full-wheel drive mode is selected, it is possible to perform the switch to the full-wheel drive mode and the engine start at the same time. Therefore, there is a concern that the hybrid vehicle generates an impact and causes discomfort to the driver.

[0008] The present invention has been made with the above-mentioned situation as the background, and an object of the present invention is to provide a control device for a hybrid vehicle that is less likely to give a driver a sense of discomfort when the all-wheel drive mode is selected.

[0009] Solutions for solving problems

[0010] The gist of the first invention is that (a) a control device for a hybrid vehicle comprises an engine, an electric motor, and a driving force distribution device for distributing driving force to a main drive wheel and a secondary drive wheel, the control device for the hybrid vehicle comprising: (b) an engine control unit for controlling the operating state of the engine; and (c) a driving mode control unit for controlling the driving of the hybrid vehicle to realize a driving mode selected by a driver, (d) the driving mode comprises a main drive wheel driving mode for driving the vehicle by distributing the driving force only to the main drive wheel and an all-wheel drive mode for driving the vehicle by distributing the driving force to both the main drive wheel and the secondary drive wheel, and (e) when the all-wheel drive mode is selected in the main drive wheel driving mode when the engine is in a stopped state, the engine control unit maintains the stopped state of the engine until the switching from the main drive wheel driving mode to the all-wheel drive mode by the driving mode control unit is completed, and starts the engine after the driver performs a predetermined operation for driving the hybrid vehicle.

[0011] In addition, according to the second invention, in the control device of the hybrid vehicle described in the first invention, the all-wheel drive mode is a driving mode for controlling the working state of the engine in a manner that increases the ratio of the driving time of the engine to the operating time of the hybrid vehicle, that is, the driving ratio of the engine, as compared with the main drive wheel drive mode.

[0012] Furthermore, a third invention is the control device for the hybrid vehicle according to the first invention or the second invention, wherein the predetermined operation is an acceleration request operation for increasing the driving force.

[0013] In addition, according to the 4th invention, in the control device of the hybrid vehicle described in the 1st invention or the 2nd invention, the predetermined operation is an acceleration request operation to increase the driving force, and when the all-wheel drive mode is selected in the main drive wheel drive mode when the hybrid vehicle is stopped, the engine control unit maintains the stopped state of the engine when a switching operation is performed from a state in which the vehicle power transmission device selected to transmit the driving force cannot transmit the driving force to a state in which the vehicle power transmission device is selected to transmit the driving force. When the acceleration request operation is performed after the switching operation, the engine is started.

[0014] In addition, the fifth invention is a control device for the hybrid vehicle described in the first invention or the second invention, further comprising a motor control unit, wherein when the engine is set to a stopped state when switching from the main drive wheel drive mode to the all-wheel drive mode, the motor control unit outputs a predetermined torque from the motor to produce a creep phenomenon.

[0015] In addition, according to the 6th invention, in the control device of the hybrid vehicle described in the 5th invention, when the main drive wheel drive mode is selected in the all-wheel drive mode when the predetermined torque is output from the electric motor, the motor control unit reduces the output torque of the electric motor from the predetermined torque to zero after a predetermined time has passed since the switching from the all-wheel drive mode to the main drive wheel drive mode performed by the driving mode control unit is completed.

[0016] In addition, according to the 7th invention, in the control device of the hybrid vehicle described in the 6th invention, when the vehicle power transmission device for transmitting the driving force is in a non-driving position where it cannot transmit the driving force and switches from the all-wheel drive mode to the main drive wheel drive mode, the motor control unit reduces the output torque of the motor.

[0017] In addition, the 8th invention is a control device for a hybrid vehicle described in the 1st invention or the 2nd invention, wherein the all-wheel drive mode includes a low-speed all-wheel drive mode in which a transmission provided in the driving force distribution device selectively forms a low-speed segment and a high-speed segment through the operation of a meshing clutch and the transmission is set to the low-speed segment, and a high-speed all-wheel drive mode in which the transmission is set to the high-speed segment, and the main drive wheel drive mode is a high-speed main drive wheel drive mode in which the transmission is set to the high-speed segment, and the control device for the hybrid vehicle also includes a motor control unit, and when the hybrid vehicle is stopped, when the engine is set to a stopped state when switching from the high-speed main drive wheel drive mode to the high-speed all-wheel drive mode, the motor control unit outputs a predetermined torque from the motor to produce a creep phenomenon.

[0018] In addition, according to the 9th invention, in the control device of the hybrid vehicle described in the 8th invention, when controlling in the high-speed main drive wheel drive mode when both the engine and the electric motor are set to a stopped state, if the high-speed all-wheel drive mode is selected, the electric motor control unit outputs the predetermined torque from the electric motor.

[0019] In addition, according to the 10th invention, in the control device of the hybrid vehicle described in the 1st invention or the 2nd invention, the engine control unit allows intermittent operation of the engine by switching the engine between a running state and a stopped state in the main drive wheel drive mode, and prohibits switching of the engine from a running state to a stopped state in the all-wheel drive mode.

[0020] Effects of the Invention

[0021] According to the first invention, when the all-wheel drive mode is selected in the main drive wheel drive mode when the engine is stopped, the engine is kept stopped until the switch from the main drive wheel drive mode to the all-wheel drive mode is completed, and the engine is started after the driver performs a predetermined operation for driving the hybrid vehicle, thereby avoiding the switching to the all-wheel drive mode and the engine starting at the same time, preventing the occurrence of shock, and the engine is started based on the driver's operation related to the engine start. As a result, when the all-wheel drive mode is selected, it is less likely to cause discomfort to the driver.

[0022] Furthermore, according to the second invention, the all-wheel drive mode is a driving mode in which the operating state of the engine is controlled in a manner that the driving ratio of the engine is increased compared to the main drive wheel drive mode, so that even in the all-wheel drive mode in which the driving ratio of the engine is increased in priority to the power performance, the engine can be maintained in a stopped state before the operation of actually driving the hybrid vehicle is performed. Thus, both energy efficiency and power performance can be achieved.

[0023] In addition, according to the third invention, the predetermined operation is an acceleration request operation for increasing the driving force, so the engine can be kept in a stopped state before the driver's intention to start or accelerate can be confirmed. This can reduce the discomfort to the driver. In addition, energy efficiency can be improved.

[0024] In addition, according to the fourth invention, the predetermined operation is an acceleration request operation for increasing the driving force, and when the all-wheel drive mode is selected in the main drive wheel drive mode when the hybrid vehicle is stopped, when a switching operation is performed from a state of selecting a non-driving position of the vehicle power transmission device to a state of selecting a driving position, the engine is maintained in a stopped state, and when the acceleration request operation is performed after the switching operation, the engine is started, so that the engine cannot be started only by a preparatory operation for actually driving the hybrid vehicle performed before the acceleration request operation, and the engine can be maintained in a stopped state until the driver's intention to start and the intention to accelerate can be confirmed. As a result, energy efficiency can be improved.

[0025] According to the fifth invention, when the engine is stopped when switching from the main drive wheel drive mode to the all-wheel drive mode, a predetermined torque that causes a creep phenomenon is output from the electric motor, thereby improving energy efficiency while suppressing deterioration of acceleration responsiveness.

[0026] In addition, according to the sixth invention, when the main drive wheel drive mode is selected in the all-wheel drive mode when the predetermined torque is output from the electric motor, the output torque of the electric motor is reduced from the predetermined torque to zero after a predetermined time has passed since the switch from the all-wheel drive mode to the main drive wheel drive mode is completed, thereby suppressing the deterioration of the acceleration responsiveness after switching to the main drive wheel drive mode and improving energy efficiency.

[0027] In addition, according to the seventh invention, when switching from the all-wheel drive mode to the main drive wheel drive mode when the vehicle power transmission device is in a non-driving position, the output torque of the electric motor is reduced, thereby being able to appropriately improve energy efficiency when no preparatory operations are performed for actually driving the hybrid vehicle.

[0028] Furthermore, according to the eighth invention, when the hybrid vehicle is stopped, when the engine is set to a stopped state when switching from the high-speed main drive wheel drive mode to the high-speed all-wheel drive mode, the predetermined torque that generates the creep phenomenon is output from the electric motor, so that in the high-speed all-wheel drive mode, the rotation required for the operation of the meshing clutch provided in the transmission of the driving force distribution device can be easily obtained by the rotation of the electric motor. That is, in the high-speed all-wheel drive mode, preparations for switching to the low-speed all-wheel drive mode can be made.

[0029] In addition, according to the ninth invention, when the high-speed all-wheel drive mode is selected during control in the high-speed main drive wheel drive mode when both the engine and the electric motor are set to a stopped state, a predetermined torque is output from the electric motor, so that even if the engine is set to a stopped state after switching to the high-speed all-wheel drive mode, preparation for switching to the low-speed all-wheel drive mode can be reliably performed.

[0030] In addition, according to the tenth invention, in the main drive wheel drive mode, the engine is allowed to operate intermittently, so that energy efficiency can be easily improved. On the other hand, in the all-wheel drive mode, the engine is prohibited from switching from the running state to the stopped state, so that the responsiveness of the driving force can be easily ensured. Alternatively, the busy feeling caused by the engine being set to the running state immediately after being set to the stopped state in the all-wheel drive mode can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The diagram is a diagram for explaining a schematic configuration of a vehicle to which the present invention is applied, and is a diagram for explaining control functions for various controls in the vehicle and a main part of the control system.

[0032] Figure 2 Yes Description Figure 1 Schematic diagram of the structure of the transfer case.

[0033] Figure 3This is a flowchart for explaining a main part of the control operation of the electronic control device, and is a flowchart for explaining the control operation for preventing the driver from feeling uncomfortable when the AWD mode is selected.

[0034] Figure 4 is a flowchart for explaining the main part of the control operation of the electronic control device, is a flowchart for explaining the control operation when switching from the AWD mode to the 2WD mode during the creep torque output, and is Figure 3 Flowcharts of different embodiments.

[0035] Description of Reference Numerals

[0036] 10: vehicle (hybrid vehicle), 12: engine, 14: front wheel (auxiliary drive wheel), 16: rear wheel (main drive wheel), 18: power transmission device (power transmission device for vehicle), 26: transfer case (driving force distribution device), 90: electronic control device (control device), 92a: engine control unit, 92b: electric motor control unit, 96: driving mode control unit, 106: subtransmission (transmission), 120: meshing clutch for subtransmission (meshing clutch), MG: electric motor. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0038] [Example 1]

[0039] Figure 1 1 is a diagram for explaining a schematic structure of a vehicle 10 to which the present invention is applied, and is a diagram for explaining control functions for various controls in the vehicle 10 and a main part of the control system. Figure 1 In the figure, the vehicle 10 is a hybrid vehicle including an engine 12 and an electric motor MG as driving force sources for traveling. In addition, the vehicle 10 includes a pair of left and right front wheels 14, a pair of left and right rear wheels 16, and a power transmission device 18. The power transmission device 18 is a vehicle power transmission device that transmits the driving force from the engine 12 and the like to the front wheels 14 and the rear wheels 16, respectively.

[0040] The vehicle 10 is an all-wheel drive vehicle based on a main drive wheel drive vehicle of the FR (front engine rear wheel drive) method. The vehicle 10 is a vehicle having four wheels, including two front wheels 14 and two rear wheels 16, and is therefore also a four-wheel drive vehicle based on a two-wheel drive vehicle of the FR method. In the present embodiment, main drive wheel drive is synonymous with two-wheel drive (=2WD), and all-wheel drive (=AWD) is synonymous with four-wheel drive (=4WD). The rear wheel 16 is a main drive wheel that becomes a drive wheel in both 2WD driving and AWD driving. In addition, the front wheel 14 is a secondary drive wheel that becomes a driven wheel in 2WD driving and a drive wheel in AWD driving. 2WD driving is driving in a 2WD state in which the driving force from the engine 12, etc. is transmitted only to the rear wheel 16. AWD driving is driving in an AWD state in which the driving force from the engine 12, etc. is transmitted to the rear wheel 16 and the front wheel 14.

[0041] The engine 12 is a well-known internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 is controlled by an electronic control device 90 described later to control an engine control device 50 provided in the vehicle 10 including a throttle actuator, a fuel injection device, an ignition device, etc., thereby controlling an engine torque Te which is an output torque of the engine 12.

[0042] The electric motor MG is a rotating electric machine having the function of an engine that generates mechanical power from electric power and the function of a generator that generates electric power from mechanical power, and is a so-called electric generator. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The battery 54 is a storage device that sends and receives electric power to the electric motor MG. The electric motor MG controls the MG torque Tm, which is the output torque of the electric motor MG, by controlling the inverter 52 using an electronic control device 90 described later. For example, when the rotation direction of the electric motor MG is the same rotation direction as that of the engine 12 when driving, that is, positive rotation, the MG torque Tm is a power running torque in a positive torque on the acceleration side, and is a regenerative torque in a negative torque on the deceleration side. The electric power is also synonymous with electric energy when not specifically distinguished. The power is also synonymous with torque and force when not specifically distinguished.

[0043] The power transmission device 18 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, a transfer case 26, a rear propeller shaft 28, a rear differential 30, a pair of left and right rear drive shafts 32, a front propeller shaft 34, a front differential 36, and a pair of left and right front drive shafts 38. In the power transmission device 18, the K0 clutch 20, the torque converter 22, and the automatic transmission 24 are arranged in a housing 40 as a non-rotating member attached to the vehicle body. In addition, the power transmission device 18 includes an engine connecting shaft 42 connecting the engine 12 and the K0 clutch 20, a motor connecting shaft 44 connecting the K0 clutch 20 and the torque converter 22, and the like in the housing 40.

[0044] The K0 clutch 20 is a clutch provided in the power transmission path between the engine 12 and the torque converter 22. That is, the torque converter 22 is connected to the engine 12 via the K0 clutch 20. The automatic transmission 24 is interposed in the power transmission path between the torque converter 22 and the transfer case 26. That is, the torque converter 22 is connected to the transmission input shaft 46, which is an input rotating member of the automatic transmission 24. The transfer case 26 is connected to the transmission output shaft 48, which is an output rotating member of the automatic transmission 24.

[0045] The electric motor MG is connected to the electric motor connecting shaft 44 in a power-transmittable manner in the housing 40. In other words, the electric motor MG is connected to the power transmission path between the K0 clutch 20 and the torque converter 22 in a power-transmittable manner. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 in a power-transmittable manner without passing through the K0 clutch 20.

[0046] The torque converter 22 is a fluid transmission device that transmits the driving forces from the engine 12 and the motor MG to the transmission input shaft 46 via a fluid. The automatic transmission 24 is a mechanical transmission device that transmits the driving forces from the engine 12 and the motor MG to the transfer case 26 .

[0047] The front differential 36 is a differential with an ADD (Automatic Disconnecting Differential) mechanism 37. The ADD mechanism 37 is, for example, an engaging clutch that functions as a disconnecting clutch. The ADD mechanism 37 switches the front differential 36 to a locked state by setting the operating state, i.e., the control state, to an engaged state. On the other hand, the ADD mechanism 37 switches the front differential 36 to a free state by setting the control state to a released state. The ADD mechanism 37 switches the control state by controlling an ADD mechanism actuator 56 provided in the vehicle 10 using an electronic control device 90 described later.

[0048] The automatic transmission 24 is, for example, a well-known planetary gear type automatic transmission having one or more sets of planetary gear devices and a plurality of engagement devices CB (not shown). The engagement device CB is, for example, a well-known hydraulic friction engagement device. The engagement devices CB change their respective torque capacities, i.e., CB torques Tcb, by means of the CB hydraulic pressure PRcb after pressure regulation supplied from the hydraulic control circuit 58 provided in the vehicle 10, thereby switching control states such as an engagement state and a release state. The hydraulic control circuit 58 is controlled by an electronic control device 90 described later.

[0049] The automatic transmission 24 is a stepped transmission that forms any gear stage among a plurality of gear stages (also called gear stages) with different speed ratios (also called gear ratios) γat (=AT input speed Ni / AT output speed No) by engaging any of the engagement devices CB. The automatic transmission 24 switches the gear stage formed according to the accelerator operation of the driver (=driver), the vehicle speed V, etc., by using the electronic control device 90 described later. The AT input speed Ni is the speed of the transmission input shaft 46, which is the input speed of the automatic transmission 24. The AT output speed No is the speed of the transmission output shaft 48, which is the output speed of the automatic transmission 24.

[0050] The K0 clutch 20 is a wet or dry friction engagement device composed of, for example, a multi-plate or single-plate clutch pressed by a hydraulic actuator. The K0 clutch 20 changes the torque capacity of the K0 clutch 20, i.e., the K0 torque Tk0, by using the regulated K0 hydraulic pressure PRk0 supplied from the hydraulic control circuit 58, thereby switching the control state such as the engaged state and the released state.

[0051] The transfer case 26 selectively switches, for example, the interruption and connection of the power transmission between the rear propeller shaft 28 and the front propeller shaft 34. Thus, the transfer case 26 transmits the driving force transmitted from the automatic transmission 24 only to the rear wheels 16, or distributes it to the front wheels 14 and the rear wheels 16. In this way, the transfer case 26 is a driving force distribution device that distributes the driving force to the main drive wheels and the auxiliary drive wheels.

[0052] Figure 2 2 is a schematic diagram for explaining the structure of the transfer case 26. Figure 2 1 is a development view showing the axes of the input shaft 102, the first output shaft 104, and the second output shaft 112 described later on a common plane. Figure 2In the embodiment, the transfer case 26 includes a transfer case 100 which is a non-rotating member connected to the vehicle rear side of the case 40. The transfer case 26 includes an input shaft 102, a first output shaft 104, a sub-transmission 106, a power distribution clutch 108, a drive gear 110, etc., which are arranged on a common first axis CS1, in the transfer case 100. In addition, the transfer case 26 includes a second output shaft 112 and a driven gear 114, which are arranged on a common second axis CS2, in the transfer case 100. In addition, the transfer case 26 includes a chain 116 connecting the drive gear 110 and the driven gear 114.

[0053] The input shaft 102 is connected to the transmission output shaft 48. The first output shaft 104 is connected to the rear transmission shaft 28. The second output shaft 112 is connected to the front transmission shaft 34. The drive gear 110 is configured to selectively switch between allowing and preventing relative rotation with respect to the first output shaft 104. The driven gear 114 is configured to be unable to rotate relative to the second output shaft 112.

[0054] The auxiliary transmission 106 is provided with a planetary gear device 118 and an auxiliary transmission meshing clutch 120. The auxiliary transmission meshing clutch 120 has a high-side meshing mechanism 122 for establishing a high-speed gear stage with a small gear ratio, i.e., a high-speed stage GSH, and a low-side meshing mechanism 124 for establishing a low-speed gear stage with a large gear ratio, i.e., a low-speed stage GSL. The high-side meshing mechanism 122 and the low-side meshing mechanism 124 are meshing clutches with synchronous meshing mechanisms, for example. That is, the auxiliary transmission 106 is a transmission that selectively forms a low-speed stage GSL and a high-speed stage GSH by operating the auxiliary transmission meshing clutch 120 as a meshing clutch. The transfer case 26 transmits the rotation of the input shaft 102 to the first output shaft 104 via the auxiliary transmission 106.

[0055] The meshing clutch 108 for power distribution is an engagement device for selectively switching between the permission and prevention of the relative rotation of the drive gear 110 relative to the first output shaft 104. The meshing clutch 108 for power distribution is, for example, a meshing clutch with a synchronous meshing mechanism. By making the meshing clutch 108 for power distribution a released state, the drive gear 110 can rotate relative to the first output shaft 104 around the first axis CS1. As a result, power cannot be transmitted between the first output shaft 104 and the second output shaft 112 via the drive gear 110, etc. On the other hand, by making the meshing clutch 108 for power distribution a meshing state, the drive gear 110 is prevented from rotating relative to the first output shaft 104 around the first axis CS1. As a result, power can be transmitted between the first output shaft 104 and the second output shaft 112 via the drive gear 110, the chain 116, and the driven gear 114, etc.

[0056] The transfer case 26 further includes a shift actuator 126 fixed to the transfer case 100. The shift actuator 126 is an actuator for operating the auxiliary transmission dog clutch 120 and the power distribution dog clutch 108, respectively.

[0057] Back to Figure 1 When the power distribution meshing clutch 108 is set to the engaged state in the transfer case 26 and the ADD mechanism 37 is set to the engaged state in the front differential 36, the driving force distributed by the transfer case 26 to the second output shaft 112 is transmitted to the front differential 36 via the front propeller shaft 34 and to the front wheels 14 via the front drive shaft 38. In addition, the remaining driving force not distributed by the transfer case 26 to the second output shaft 112 is transmitted to the rear differential 30 via the rear propeller shaft 28 and to the rear wheels 16 via the rear drive shaft 32. As a result, the vehicle 10 is in the AWD state.

[0058] On the other hand, when the power distribution clutch 108 is released in the transfer case 26, the drive force is transmitted only to the rear wheels 16 by the transfer case 26, so that the vehicle 10 is in the 2WD state. In the vehicle 10, for example, the ADD mechanism 37 is released in conjunction with the 2WD state.

[0059] In the vehicle 10, when the K0 clutch 20 is engaged, the engine 12 and the torque converter 22 are connected in a power-transmitting manner. On the other hand, when the K0 clutch 20 is released, the power transmission between the engine 12 and the torque converter 22 is blocked. Since the motor MG is connected to the torque converter 22, the K0 clutch 20 functions as a clutch that disconnects and connects the engine 12 and the motor MG.

[0060] In the power transmission device 18, when the K0 clutch 20 is engaged, the driving force output from the engine 12 is transmitted from the engine connecting shaft 42 to the transfer case 26 via the K0 clutch 20, the motor connecting shaft 44, the torque converter 22, the automatic transmission 24, etc. in sequence. In addition, regardless of the control state of the K0 clutch 20, the driving force output from the motor MG is transmitted from the motor connecting shaft 44 to the transfer case 26 via the torque converter 22, the automatic transmission 24, etc. in sequence. And, in the case of the 2WD state, the driving force transmitted to the transfer case 26 is transmitted from the transfer case 26 to the rear wheels 16. Alternatively, in the case of the AWD state, the driving force transmitted to the transfer case 26 is distributed to the rear wheel 16 side and the front wheel 14 side through the transfer case 26.

[0061] The vehicle 10 is provided with a MOP60 as a mechanical oil pump, an EOP62 as an electric oil pump, a pump motor 64, etc. The MOP60 is connected to the motor connecting shaft 44, and is driven to rotate by the driving force source (engine 12, motor MG) to eject the working oil OIL used in the power transmission device 18. The pump motor 64 is a motor dedicated to the EOP62 for rotating the EOP62. The EOP62 is driven to rotate by the pump motor 64 to eject the working oil OIL. The working oil OIL ejected by the MOP60 and EOP62 is supplied to the hydraulic control circuit 58. The hydraulic control circuit 58 supplies the CB hydraulic pressure PRcb, the K0 hydraulic pressure PRk0, etc., which are respectively regulated based on the working oil OIL ejected by the MOP60 and / or EOP62.

[0062] The vehicle 10 is further provided with an electronic control device 90 including a control device of the vehicle 10 associated with control of the engine 12 and the like. The electronic control device 90 is configured to include a so-called microcomputer including, for example, a CPU, a RAM, a ROM, an input / output interface, etc. The CPU uses the temporary storage function of the RAM and performs signal processing according to a program pre-stored in the ROM to execute various controls of the vehicle 10. The electronic control device 90 is configured to include various computers for engine control, motor control, hydraulic control, etc. as necessary.

[0063] Various signals based on detection values ​​of various sensors (e.g., an engine speed sensor 70, an input speed sensor 71, an output speed sensor 72, an MG speed sensor 73, a wheel speed sensor 74, an accelerator opening sensor 75, a throttle opening sensor 76, a brake pedal sensor 77, a G sensor 78, a yaw rate sensor 79, a shift position sensor 80, a drive switching dial switch 81, a battery sensor 82, an oil temperature sensor 83, etc.) provided in the vehicle 10 are supplied to the electronic control unit 90 (e.g., the engine speed Ne of the engine 12, the AT input speed Ni, the AT output speed No corresponding to the vehicle speed V, the MG speed Nm of the motor MG, the wheel speed Nm of each wheel of the front wheel 14 and the rear wheel 16). degree Nr, the accelerator operation amount indicating the magnitude of the driver's acceleration operation, namely the accelerator opening θacc, the opening of the electronic throttle, namely the throttle opening θth, the signal indicating the state of the brake pedal for operating the wheel brake being operated by the driver, namely the brake-on signal Bon, the longitudinal acceleration Gx and the left and right acceleration Gy of the vehicle 10, the angular velocity of rotation of the vehicle 10 around the vertical axis, namely the yaw rate Ryaw, the shift operation position POSsh indicating the operation position of the shift lever 66 of the vehicle 10, the signal indicating the operation position of the drive switching dial switch 81, namely the dial operation position POSdl, the battery temperature THbat of the battery 54, the battery charge and discharge current Ibat, the battery voltage Vbat, the temperature of the working oil OIL, namely the working oil temperature THoil, etc.).

[0064] The shift lever 66 is a shift operating member operated by the driver to any of a plurality of shift operating positions POSsh. The shift operating position POSsh is an operating position of the shift lever 66 for selecting a shift position of the power transmission device 18, particularly the automatic transmission 24, and includes, for example, P, R, N, and D operating positions.

[0065] The P operation position is a parking operation position in which the parking position (=P position) as the parking position of the automatic transmission 24 is selected. The P position of the automatic transmission 24 is a shift position of the automatic transmission 24 in which the automatic transmission 24 is set to a neutral state and the rotation of the transmission output shaft 48 is mechanically blocked. The neutral state of the automatic transmission 24 is a state in which the automatic transmission 24 cannot transmit the driving force, for example, by setting the engagement device CB to a released state so that the power transmission of the automatic transmission 24 is blocked. The state in which the rotation of the transmission output shaft 48 is mechanically blocked is a parking lock state in which the transmission output shaft 48 is fixed to be non-rotatable by a known parking lock mechanism provided in the vehicle 10. The R operation position is a reverse travel operation position in which the reverse travel position (=R position) as the reverse travel position of the automatic transmission 24 is selected. The R position of the automatic transmission 24 is a shift position of the automatic transmission 24 that enables the vehicle 10 to travel in reverse. The N operating gear position is a neutral operating gear position in which the neutral gear position (=N gear position) as the neutral position of the automatic transmission 24 is selected. The N gear position of the automatic transmission 24 is a shift gear position of the automatic transmission 24 in which the automatic transmission 24 is in a neutral state. The D operating gear position is a forward travel operating gear position in which the forward travel gear position (=D gear position) as the forward travel position of the automatic transmission 24 is selected. The D gear position of the automatic transmission 24 is a shift gear position of the automatic transmission 24 in which the automatic speed change control of the automatic transmission 24 is performed so that the vehicle 10 can travel forward. The P gear position and the N gear position of the automatic transmission 24 are non-driving positions of the automatic transmission 24 in which the automatic transmission 24 cannot transmit the driving force. The R gear position and the D gear position of the automatic transmission 24 are driving positions of the automatic transmission 24 in which the automatic transmission 24 can transmit the driving force.

[0066] The drive switching dial switch 81 is, for example, provided near the driver's seat and is a dial switch operated by the driver to select the driving state of the vehicle 10. The drive switching dial switch 81 has, for example, three operating positions, namely, "H-2WD", "H-AWD" and "L-AWD". When the operating position of the drive switching dial switch 81 is set to "H-2WD", the high-speed 2WD mode is selected as the driving mode. When the operating position of the drive switching dial switch 81 is set to "H-AWD", the high-speed AWD mode is selected as the driving mode. When the operating position of the drive switching dial switch 81 is set to "L-AWD", the low-speed AWD mode is selected as the driving mode. The high-speed 2WD mode is a driving mode in which the driving state of the vehicle 10 is set to the 2WD state in which the auxiliary transmission 106 of the transfer case 26 is set to the high-speed level GSH. In the 2WD mode, which is a driving mode in which the driving force is distributed only to the rear wheels 16 and the vehicle travels, the auxiliary transmission 106 is basically set to the high-speed level GSH. That is, in this embodiment, the 2WD mode is the high-speed 2WD mode. The high-speed AWD mode is a driving mode in which the driving state of the vehicle 10 is set to the AWD state in which the auxiliary transmission 106 is set to the high-speed GSH. The low-speed AWD mode is a driving mode in which the driving state of the vehicle 10 is set to the AWD state in which the auxiliary transmission 106 is set to the low-speed GSL. In the present embodiment, the driving mode in which the driving force is distributed to both the rear wheels 16 and the front wheels 14 for driving, that is, the AWD mode, includes the low-speed AWD mode and the high-speed AWD mode. In addition, the drive switching dial switch 81 is not limited to the above-mentioned dial type, and may be, for example, a sliding type, an interactive conversion type, etc.

[0067] Various command signals (e.g., an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the electric motor MG, an ADD switching control command signal Sadd for switching the control state of the ADD mechanism 37, a CB hydraulic control command signal Scb for controlling the engagement device CB, a K0 hydraulic control command signal Sk0 for controlling the K0 clutch 20, an EOP control command signal Seop for controlling the EOP62, a high-low switching control command signal Sh1 for switching the gear stage of the auxiliary transmission 106 between the high gear stage GSH and the low gear stage GSL, a drive state switching control command signal Swd for controlling the switching between the 2WD state and the AWD state realized by the transfer case 26, etc.) are output from the electronic control device 90 to each device of the vehicle 10 (e.g., the engine control device 50, the inverter 52, the ADD mechanism actuator 56, the hydraulic control circuit 58, the pump motor 64, the shift actuator 126, etc.).

[0068] The electronic control device 90 includes a hybrid control unit 92 as a hybrid control means, a hydraulic control unit 94 as a hydraulic control means, and a driving mode control unit 96 as a driving mode control means in order to realize various controls of the vehicle 10 .

[0069] The hybrid control unit 92 includes the functions of an engine control unit 92a as an engine control component for controlling the operation of the engine 12 and a motor control unit 92b as a motor control component for controlling the operation of the motor MG via the inverter 52. These control functions are used to perform hybrid drive control based on the engine 12 and the motor MG.

[0070] The hybrid control unit 92 calculates the driver's drive requirement for the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to the drive requirement map. The drive requirement map is a relationship that is obtained and stored in advance through experiments or design, that is, a predetermined relationship. The drive requirement is, for example, the required drive torque Trdem of the drive wheels (rear wheels 16, front wheels 14). In other words, the required drive torque Trdem [Nm] is the required drive power Prdem [W] at the vehicle speed V at this time. As the drive requirement, the required drive force Frdem [N] of the drive wheels, the required AT output torque of the transmission output shaft 48, etc. can also be used. In the calculation of the drive requirement, the AT output speed No, etc. can also be used instead of the vehicle speed V.

[0071] The hybrid control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the motor MG in consideration of transmission loss, auxiliary machine load, gear ratio γat of the automatic transmission 24, chargeable power Win of the battery 54, dischargeable power Wout, etc., so as to realize the required driving power Prdem. The engine control command signal Se is, for example, a command value of the power of the engine 12, that is, the engine power Pe, which outputs the engine torque Te at the current engine speed Ne. The MG control command signal Sm is, for example, a command value of the power consumption Wm of the motor MG, which outputs the MG torque Tm at the current MG speed Nm.

[0072] The chargeable power Win of the battery 54 is the maximum power that can be inputted, which specifies the limit of the input power of the battery 54, and indicates the input limit of the battery 54. The dischargeable power Wout of the battery 54 is the maximum power that can be outputted, which specifies the limit of the output power of the battery 54, and indicates the output limit of the battery 54. The chargeable power Win and the dischargeable power Wout of the battery 54 are calculated by the electronic control unit 90, for example, based on the battery temperature THbat and the state of charge value SOC[%] of the battery 54. The state of charge value SOC of the battery 54 is a value indicating the state of charge corresponding to the charge amount of the battery 54, and is calculated by the electronic control unit 90, for example, based on the battery charge and discharge current Ibat and the battery voltage Vbat.

[0073] The hybrid control unit 92 sets the driving mode to the motor driving (=EV driving) mode when the required driving torque Trdem is provided only by the output of the electric motor MG. In the EV driving mode, the hybrid control unit 92 performs EV driving in which the vehicle is driven only by the electric motor MG as a driving force source in the released state of the K0 clutch 20. On the other hand, the hybrid control unit 92 sets the driving mode to the engine driving mode, i.e., the hybrid driving (=HV driving) mode, when the required driving torque Trdem cannot be provided without at least the output of the engine 12. In the HV driving mode, the hybrid control unit 92 performs engine driving in which the vehicle is driven at least by the engine 12 as a driving force source in the engaged state of the K0 clutch 20, i.e., the HV driving mode. On the other hand, even when the required driving torque Trdem is provided only by the output of the electric motor MG, the hybrid control unit 92 establishes the HV driving mode when the state of charge value SOC of the battery 54 is less than a predetermined engine start threshold value SOCengf, when preheating of the engine 12, etc. is required, etc. The engine start threshold value SOCengf is a predetermined threshold value of the state of charge value SOC for judging whether it is necessary to forcibly start the engine 12 to charge the battery 54. In this way, the hybrid control unit 92 automatically stops the engine 12 during HV driving, restarts the engine 12 after the engine is stopped, or starts the engine 12 during EV driving, thereby switching the EV driving mode and the HV driving mode based on the required drive torque Trdem, etc.

[0074] The engine control unit 92a determines whether there is a request to start the engine 12. For example, when in the EV driving mode, the engine control unit 92a determines whether there is a request to start the engine 12 based on whether the required drive torque Trdem is greater than the range provided by the output of the motor MG alone, whether preheating of the engine 12 is required, or whether the state of charge value SOC of the battery 54 is less than the engine start threshold value SOCengf.

[0075] When the engine control unit 92a determines that there is a request to start the engine 12, the hydraulic control unit 94 outputs a K0 hydraulic control command signal Sk0 for controlling the K0 clutch 20 in the released state to the engaged state to the hydraulic control circuit 58 in order to obtain a K0 torque Tk0 for transmitting a torque for increasing the engine speed Ne to the engine 12 side, that is, a torque required for starting the engine 12. In the present embodiment, the torque required for starting the engine 12 is referred to as a required starting torque Tcrn.

[0076] When the engine control unit 92a determines that there is a request to start the engine 12, the motor control unit 92b outputs an MG control command signal Sm to the inverter 52 for causing the motor MG to output the required cranking torque Tcrn in response to the switching of the K0 clutch 20 to the engaged state by the hydraulic control unit 94.

[0077] When determining that there is a request to start the engine 12, the engine control unit 92a outputs an engine control command signal Se for starting fuel supply, engine ignition, etc. to the engine control device 50 in conjunction with the start of the engine 12 by the K0 clutch 20 and the motor MG.

[0078] When the engine 12 is started during EV driving, the motor control unit 92b outputs an MG torque Tm corresponding to the required starting torque Tcrn from the motor MG in addition to the MG torque Tm for EV driving, i.e., the MG torque Tm for generating the driving torque Tr. Therefore, during EV driving, it is necessary to prepare for the start of the engine 12 and ensure the required starting torque Tcrn. Therefore, the range in which the required driving torque Trdem is provided only by the output of the motor MG becomes a torque range in which the required starting torque Tcrn is subtracted from the maximum torque of the motor MG that can be output. The maximum torque of the motor MG that can be output is the maximum MG torque Tm that can be output by the dischargeable power Wout of the battery 54.

[0079] The engine control unit 92a determines whether there is a stop request for the engine 12. For example, in the HV driving mode, the engine control unit 92a determines whether there is a stop request for the engine 12 based on whether the required drive torque Trdem is within the range provided by the output of the motor MG alone, whether preheating of the engine 12 is not required, whether the charge state value SOC of the battery 54 is greater than the engine start threshold value SOCengf, etc.

[0080] When determining that there is a request to stop the engine 12, the engine control unit 92a outputs the engine control command signal Se for stopping the fuel supply to the engine 12 to the engine control device 50. That is, when the engine 12 is stopped, the engine control unit 92a outputs the engine control command signal Se for controlling the engine 12 to stop the operation of the engine 12 to the engine control device 50.

[0081] When the engine control unit 92 a determines that there is a request to stop the engine 12 , the hydraulic control unit 94 outputs a K0 hydraulic control command signal Sk0 for controlling the engaged K0 clutch 20 to a released state to the hydraulic control circuit 58 .

[0082] In this manner, the engine control unit 92 a controls the operating state of the engine 12 based on the travel mode and the state of the vehicle 10 to start or stop the engine 12 .

[0083] The hydraulic control unit 94 uses, for example, a shift map as a predetermined relationship to determine the shift of the automatic transmission 24, and outputs the CB hydraulic control command signal Scb for executing the shift control of the automatic transmission 24 to the hydraulic control circuit 58 as needed. The shift map is, for example, a predetermined relationship having a shift line for determining the shift of the automatic transmission 24 on a two-dimensional coordinate with the vehicle speed V and the required drive torque Trdem as variables. In the shift map, the AT output speed No and the like may be used instead of the vehicle speed V, or the required drive force Frdem, the accelerator opening θacc, the throttle opening θth and the like may be used instead of the required drive torque Trdem.

[0084] The driving mode control unit 96 controls the driving of the vehicle 10 so as to realize the driving mode selected by the driver. Specifically, the driving mode includes a 2WD mode, namely a high 2WD mode, and an AWD mode including a low AWD mode and a high AWD mode.

[0085] When the high-speed 2WD mode is selected using the drive switching dial switch 81, the driving mode control unit 96 outputs a high-low switching control command signal Shl for setting the gear stage of the sub-transmission 106 to the high-speed stage GSH and a driving state switching control command signal Swd for setting the power distribution clutch 108 to the released state to the shift actuator 126, and outputs an ADD switching control command signal Sadd for setting the ADD mechanism 37 to the released state to the ADD mechanism actuator 56.

[0086] When the high-speed AWD mode is selected using the drive switching dial switch 81, the driving mode control unit 96 outputs a high-low switching control command signal Shl for setting the gear stage of the auxiliary transmission 106 to the high-speed stage GSH and a driving state switching control command signal Swd for setting the power distribution clutch 108 to the engaged state to the shift actuator 126, and outputs an ADD switching control command signal Sadd for setting the ADD mechanism 37 to the engaged state to the ADD mechanism actuator 56.

[0087] When the low-speed AWD mode is selected using the drive switching dial switch 81, the driving mode control unit 96 outputs a high-low switching control command signal Shl for setting the gear stage of the sub-transmission 106 to the low-speed stage GSL and a driving state switching control command signal Swd for setting the power distribution clutch 108 to the engaged state to the shift actuator 126, and outputs an ADD switching control command signal Sadd for setting the ADD mechanism 37 to the engaged state to the ADD mechanism actuator 56.

[0088] Here, in the AWD mode, a larger driving force Fr is easily required compared with the 2WD mode. For the HV driving mode, since the engine 12 is in the operating state, it is easy to obtain a larger driving force Fr than in the EV driving mode. Therefore, when the AWD mode is selected with the engine 12 in the stopped state, it is considered to start the engine 12 and set it to the operating state. The AWD mode is a driving mode in which the engine control unit 92a controls the working state of the engine 12 in a manner that increases the driving ratio Reng of the engine 12 compared with the 2WD mode. The driving ratio Reng of the engine 12 is a value of the ratio of the driving time of the engine 12 to the operating time of the vehicle 10. The operating time of the vehicle 10 is the time during which the main power supply of the vehicle 10 is in the on state, and is the total time of the driving time of the engine 12 and the stopping time of the engine 12. The driving time of the engine 12 is the time during which the engine 12 is in the operating time of the vehicle 10. The stopping time of the engine 12 is the time during which the engine 12 is in the stopped state during the operating time of the vehicle 10.

[0089] In addition, when the driver selects the AWD mode, he or she may not necessarily want to start the engine 12. Alternatively, if the engine 12 is started immediately when the AWD mode is selected, a shock may occur due to the simultaneous execution of the switch from the 2WD mode to the AWD mode and the engine start. It is desirable that the driver does not feel uncomfortable when the AWD mode is selected.

[0090] Therefore, when the engine 12 is stopped and the driving mode is the 2WD mode, the engine control unit 92a does not immediately start the engine 12 when the AWD mode is selected. When the engine control unit 92a is in the 2WD mode, when the AWD mode is selected, the engine 12 is started when the driver performs an operation that does not easily cause discomfort even when the engine 12 is started.

[0091] That is, when the AWD mode is selected in the 2WD mode when the engine 12 is stopped, the engine control unit 92a maintains the stopped state of the engine 12 until the switching from the 2WD mode to the AWD mode by the driving mode control unit 96 is completed, and starts the engine 12 after the driver performs a predetermined operation AMf for driving the vehicle 10. In addition, in the switching between the high-speed 2WD mode and the low-speed AWD mode, the switching between the high-speed segment GSH and the low-speed segment GSL and the switching between the 2WD mode and the AWD mode are required. Therefore, it is not preferable to directly switch between the high-speed 2WD mode and the low-speed AWD mode. Therefore, in the present embodiment, the switching between the high-speed 2WD mode and the high-speed AWD mode is exemplified as the switching between the 2WD mode and the AWD mode.

[0092] The scheduled operation AMf is an operation that can confirm the driver's intention to start and accelerate, such as an acceleration request operation to increase the driving force Fr. The acceleration request operation to increase the driving force Fr is, for example, an accelerator start operation to increase the required driving force Frdem. In addition, the switching operation from the state of selecting the non-driving position of the automatic transmission 24 to the state of selecting the driving position of the automatic transmission 24 is a preparatory operation performed before the acceleration request operation for actually driving the vehicle 10. Therefore, the switching operation is not included in the scheduled operation AMf. The state of selecting the non-driving position of the automatic transmission 24 is a state in which the shift operation gear position POSsh is set to the P operating gear position or the N operating gear position. The state of selecting the driving position of the automatic transmission 24 is a state in which the shift operation gear position POSsh is set to the D operating gear position or the R operating gear position. In other words, the above-mentioned switching operation is an N(P)→D(R) operation.

[0093] When the high-speed AWD mode is selected in the high-speed 2WD mode when the vehicle 10 is stopped and the engine 12 is in a stopped state, the engine control unit 92a maintains the stopped state of the engine 12 when an N(P)→D(R) operation is performed, and starts the engine 12 when an acceleration request operation is performed after the N(P)→D(R) operation.

[0094] In the switching between the high-speed AWD mode and the low-speed AWD mode, it is necessary to switch the auxiliary transmission meshing clutch 120 in the auxiliary transmission 106. In the switching of the auxiliary transmission meshing clutch 120, the input shaft 102 and the like need to rotate to a certain extent. In the switching between the high-speed AWD mode and the low-speed AWD mode, it is necessary to set the engine 12 to an operating state, or to rotate the motor MG. Alternatively, from another point of view, in the AWD mode, in order not to deteriorate the responsiveness of the driving force Fr, that is, the acceleration responsiveness, it is desired to be in a state where the driving force can be quickly output from the engine 12 or the motor MG. Therefore, in the AWD mode, if the engine 12 is in a stopped state, the motor MG is set to a rotating state. Therefore, when the engine 12 is maintained in a stopped state when switching from the high-speed 2WD mode to the high-speed AWD mode, the motor MG is set to a rotating state.

[0095] The motor control unit 92b, when the engine 12 is set to a stopped state when switching from the high 2WD mode to the high AWD mode, performs, for example, an idle speed control of the motor MG, i.e., an MG idle speed control. The MG idle speed control is a control to maintain the MG speed Nm at, for example, a predetermined idle speed of the motor MG, i.e., an MG idle speed, so that the motor MG is in an idle state. The MG idle speed control is a control such that, for example, when the accelerator is closed in the stopped state of the engine 12, by closing the brake in a temporary stop, a predetermined torque is output from the motor MG for generating a creep phenomenon in which the vehicle 10 moves slowly while the accelerator is kept closed. The predetermined torque is a creep torque for, for example, performing a brake closing operation in the stopped state of the vehicle and driving the vehicle 10 in a so-called creep driving while the accelerator is kept closed. When switching between the high AWD mode and the low AWD mode, it is necessary that the engine 12 is set to an operating state or the motor MG rotates, especially when the vehicle 10 is stopped. The MG idle control by the motor control unit 92 b is executed when the vehicle 10 is stopped.

[0096] When the High AWD mode is selected during control in the High 2WD mode when both the engine 12 and the electric motor MG are stopped, the electric motor control unit 92b executes the MG idle control to output the creep torque from the electric motor MG.

[0097] Specifically, the engine control unit 92a determines whether the engine 12 is in a stopped state.

[0098] The driving mode control unit 96 determines whether the driving mode is the high 2WD mode when the engine control unit 92a determines that the engine 12 is stopped. The driving mode control unit 96 determines whether the high AWD mode is selected based on the dial operation position POSd1 when the driving mode is determined to be the high 2WD mode.

[0099] When determining that the High AWD mode is selected, the driving mode control unit 96 switches from the High 2WD mode to the High AWD mode. The driving mode control unit 96 determines whether the switching from the High 2WD mode to the High AWD mode is completed.

[0100] When the motor control unit 92 b switches from the High 2WD mode to the High AWD mode while maintaining the stopped state of the engine 12 , if the motor MG is brought into the stopped state, the motor MG outputs creep torque.

[0101] When the driving mode control unit 96 determines that the switch from the High 2WD mode to the High AWD mode has been completed, the engine control unit 92a determines whether an acceleration request operation as a predetermined operation AMf has been performed. When the engine control unit 92a determines that the acceleration request operation has been performed, it starts the engine 12.

[0102] The high-end 2WD mode gives priority to energy efficiency compared to the AWD mode. Therefore, in the high-end 2WD mode, it is desirable to switch between the EV driving mode and the HV driving mode by performing intermittent operation of the engine to switch the engine 12 between the running state and the stopped state. On the other hand, the AWD mode gives priority to the responsiveness of the driving force Fr compared to the high-end 2WD mode. Therefore, in the AWD mode, it is desirable to prohibit the intermittent operation of the engine without making the engine 12 stop after the engine 12 is temporarily set to the running state. The engine control unit 92a allows the intermittent operation of the engine in the high-end 2WD mode. On the other hand, the engine control unit 92a prohibits the switching of the engine 12 from the running state to the stopped state in the AWD mode.

[0103] Figure 3 This is a flowchart for explaining the main part of the control operation of the electronic control device 90 , and is a flowchart for explaining the control operation for preventing the driver from feeling uncomfortable when the AWD mode is selected, and is executed repeatedly, for example.

[0104] exist Figure 3In the routine, first, in step S10 corresponding to the function of the engine control unit 92a (hereinafter, step omitted), it is determined whether the engine 12 is in a stopped state. If the determination of S10 is negative, this routine is terminated. If the determination of S10 is positive, in S20 corresponding to the function of the driving mode control unit 96, it is determined whether the driving mode is the high-end 2WD mode. If the determination of S20 is negative, this routine is terminated. If the determination of S20 is positive, in S30 corresponding to the function of the driving mode control unit 96, it is determined whether the high-end AWD mode is selected. If the determination of S30 is negative, this routine is terminated. If the determination of S30 is positive, in S40 corresponding to the function of the driving mode control unit 96, switching from the high-end 2WD mode to the high-end AWD mode is executed. Next, in S50 corresponding to the function of the motor control unit 92b, if the motor MG is set to a stopped state, a creep torque is output from the motor MG. Next, in S60 corresponding to the function of the driving mode control unit 96, it is determined whether the switch from the high-end 2WD mode to the high-end AWD mode is completed. If the determination of this S60 is negative, the process returns to the above-mentioned S40. If the determination of this S60 is positive, in S70 corresponding to the function of the engine control unit 92a, it is determined whether the acceleration request operation as the predetermined operation AMf has been performed. If the determination of this S70 is negative, the process returns to the above-mentioned S30. If the determination of this S70 is positive, in S80 corresponding to the function of the engine control unit 92a, the engine 12 is started. In addition, intermittent operation of the engine is prohibited, and switching of the engine 12 from the running state to the stopped state is prohibited.

[0105] As described above, according to the present embodiment, when the AWD mode is selected in the 2WD mode when the engine 12 is in the stopped state, the stopped state of the engine 12 is maintained until the switching from the 2WD mode to the AWD mode is completed, and the engine 12 is started after the predetermined operation AMf is performed, thereby avoiding the switching to the AWD mode and the engine starting being performed at the same time, preventing the occurrence of shock, and further, starting the engine 12 based on the driver's operation related to the engine starting. As a result, when the AWD mode is selected, it is possible to prevent the driver from feeling uncomfortable.

[0106] In addition, according to the present embodiment, the AWD mode is a driving mode in which the operating state of the engine 12 is controlled in such a manner that the driving ratio Reng of the engine 12 is increased compared to the 2WD mode. Therefore, even in the AWD mode in which the driving ratio of the engine 12 is increased by giving priority to the power performance, the engine 12 can be maintained in a stopped state before the operation of actually driving the vehicle 10 is performed. Thus, both energy efficiency and power performance can be achieved.

[0107] In addition, according to the present embodiment, the predetermined operation AMf is an acceleration request operation for increasing the driving force Fr, so the engine 12 can be maintained in a stopped state before the driver's starting intention and acceleration intention can be confirmed. This can reduce the discomfort to the driver. In addition, energy efficiency can be improved.

[0108] In addition, according to the present embodiment, when the high-speed AWD mode is selected in the high-speed 2WD mode when the vehicle 10 is stopped, the engine 12 is kept stopped when the N(P)→D(R) operation is performed, and the engine 12 is started when the acceleration request operation is performed after the N(P)→D(R) operation. Therefore, the engine 12 cannot be started only by the preparatory operation for actually driving the vehicle 10, and the engine 12 can be kept stopped until the driver's intention to start or accelerate can be confirmed. As a result, energy efficiency can be improved.

[0109] Furthermore, according to the present embodiment, when the engine 12 is stopped when switching from the High 2WD mode to the High AWD mode, creep torque is output from the electric motor MG, thereby improving energy efficiency while suppressing deterioration in acceleration responsiveness.

[0110] In addition, according to the present embodiment, when the vehicle 10 is stopped, when the engine 12 is set to a stopped state when switching from the high 2WD mode to the high AWD mode, the creep torque is output from the electric motor MG, so that in the high AWD mode, the rotation required for the operation of the auxiliary transmission meshing clutch 120 in the auxiliary transmission 106 can be easily obtained by the rotation of the electric motor MG. That is, in the high AWD mode, preparation for switching to the low AWD mode can be performed.

[0111] In addition, according to the present embodiment, when controlling in the high-speed 2WD mode when both the engine 12 and the electric motor MG are set to a stopped state, if the high-speed AWD mode is selected, a creep torque is output from the electric motor MG, so that even if the engine 12 is set to a stopped state after switching to the high-speed AWD mode, preparation for switching to the low-speed AWD mode can be reliably performed.

[0112] In addition, according to the present embodiment, in the high 2WD mode, the intermittent operation of the engine is allowed, so that it is easy to improve energy efficiency. On the other hand, in the AWD mode, the switching of the engine 12 from the running state to the stopped state is prohibited, so it is easy to ensure the responsiveness of the driving force Fr. Or, in the AWD mode, the busy feeling caused by the engine 12 being set to the running state immediately after being set to the stopped state is prevented.

[0113] Next, other embodiments of the present invention will be described. It should be noted that in the following description, the same reference numerals are given to the common parts of the embodiments, and the description thereof will be omitted.

[0114] [Example 2]

[0115] In the aforementioned first embodiment, when switching from the high-end 2WD mode to the high-end AWD mode while maintaining the stopped state of the engine 12, if the electric motor MG is set to the stopped state, the creep torque is output from the electric motor MG. Here, the high-end 2WD mode is a driving mode that emphasizes energy efficiency. Alternatively, in the high-end 2WD mode, there is no need to prepare for switching to the low-end AWD mode. Therefore, in a state where the creep torque is output from the electric motor MG, when switching from the high-end AWD mode to the high-end 2WD mode, it is considered to quickly put the electric motor MG into a stopped state and stop the output of the creep torque. However, when an operation related to driving is performed, such as when the drive switching dial switch 81 is operated, in the case where an acceleration request operation is immediately performed, the driver's requirement for starting and accelerating with good responsiveness may be high.

[0116] Therefore, when the high 2WD mode is selected in the high AWD mode when the creep torque is output from the electric motor MG, the motor control unit 92b reduces the MG torque Tm from the creep torque to zero after the predetermined time TMf has passed since the switching from the high AWD mode to the high 2WD mode by the driving mode control unit 96 is completed. The motor control unit 92b stops the output of the creep torque by stopping the electric motor MG, thereby reducing the MG torque Tm. The predetermined time TMf is, for example, a predetermined threshold value for determining that the demand for starting and accelerating with good responsiveness has become lower.

[0117] When the shift operation position POSsh is set to the P operation position or the N operation position and the automatic transmission 24 is in the non-driving position, the driver's intention to drive is considered low. When the motor control unit 92b switches from the High AWD mode to the High 2WD mode when the automatic transmission 24 is in the non-driving position, it reduces the MG torque Tm.

[0118] Specifically, the running mode control unit 96 determines whether the running mode is the high AWD mode.

[0119] When the running mode control unit 96 determines that the running mode is the High AWD mode, the motor control unit 92 b determines whether creep torque is output from the motor MG while the engine 12 is stopped.

[0120] When the motor control unit 92b determines that the creep torque is output from the electric motor MG, the travel mode control unit 96 determines whether the high 2WD mode is selected based on the dial operation position POSd1.

[0121] When determining that the High 2WD mode is selected, the driving mode control unit 96 switches from the High AWD mode to the High 2WD mode. The driving mode control unit 96 determines whether the switching from the High AWD mode to the High 2WD mode is completed.

[0122] When the driving mode control unit 96 determines that the switch from the High AWD mode to the High 2WD mode has been completed, the hydraulic control unit 94 determines whether the automatic transmission 24 is set to the non-driving position.

[0123] When the hydraulic control unit 94 determines that the automatic transmission 24 is in the non-driving position, the motor control unit 92b determines whether a predetermined time TMf has passed since the switch to the high 2WD mode is completed. When the motor control unit 92b determines that the predetermined time TMf has passed, it stops the motor MG and stops the output of the creep torque.

[0124] Figure 4 This is a flowchart for explaining the main part of the control operation of the electronic control device 90 , and is a flowchart for explaining the control operation when switching from the AWD mode to the 2WD mode during creep torque output, and is, for example, repeatedly executed. Figure 4 is with Figure 3 Flowcharts of different embodiments.

[0125] exist Figure 4In the routine, first, in S10b corresponding to the function of the driving mode control unit 96, it is determined whether the driving mode is the high-speed AWD mode. If the determination of S10b is negative, this routine is terminated. If the determination of S10b is positive, in S20b corresponding to the function of the motor control unit 92b, it is determined whether the creep torque is output from the motor MG in the stopped state of the engine 12. If the determination of S20b is negative, this routine is terminated. If the determination of S20b is positive, in S30b corresponding to the function of the driving mode control unit 96, it is determined whether the high-speed 2WD mode is selected. If the determination of S30b is negative, this routine is terminated. If the determination of S30b is positive, in S40b corresponding to the function of the driving mode control unit 96, the switching from the high-speed AWD mode to the high-speed 2WD mode is executed. Next, in S50b corresponding to the function of the driving mode control unit 96, it is determined whether the switching from the high-speed AWD mode to the high-speed 2WD mode is completed. If the judgment of S50b is negative, the routine returns to the above-mentioned S40b. If the judgment of S50b is positive, in S60b corresponding to the function of the hydraulic control unit 94, it is determined whether the automatic transmission 24 is set to the non-driving position. If the judgment of S60b is negative, the routine ends. If the judgment of S60b is positive, in S70b corresponding to the function of the motor control unit 92b, it is determined whether a predetermined time TMf has passed since the switch to the high-end 2WD mode was completed. If the judgment of S70b is negative, the routine returns to the above-mentioned S30b. If the judgment of S70b is positive, in S80b corresponding to the function of the motor control unit 92b, the motor MG is set to a stopped state and the output of the creep torque is stopped.

[0126] As described above, according to the present embodiment, when the high-end 2WD mode is selected in the high-end AWD mode when the creep torque is output from the electric motor MG, the MG torque Tm is reduced from the creep torque to zero after a predetermined time TMf has elapsed from the completion of the switch from the high-end AWD mode to the high-end 2WD mode, thereby suppressing the deterioration of the acceleration responsiveness after the switch to the high-end 2WD mode and improving the energy efficiency.

[0127] Furthermore, according to the present embodiment, when switching from the High AWD mode to the High 2WD mode when the automatic transmission 24 is in the non-driving position, the MG torque Tm is reduced, so that energy efficiency can be appropriately improved when a preparatory operation for actually driving the vehicle 10 is not performed.

[0128] As mentioned above, although the embodiment of the present invention is described in detail based on the drawings, the present invention is also applicable to other aspects.

[0129] For example, in the aforementioned embodiment 1, it is also possible to Figure 3 In S70 of the flowchart of FIG. 1 , after the N(P)→D(R) operation is performed while the vehicle 10 is stopped, it is determined whether the acceleration request operation as the predetermined operation AMf is performed. Figure 3 In addition, it is also possible to Figure 3 In S80 of the flowchart, the intermittent operation of the engine is not prohibited. Figure 3 The flowchart may also be executed while the vehicle 10 is stopped.

[0130] In addition, in the aforementioned embodiment 2, it is also possible not to execute Figure 4 In addition, Figure 4 The flowchart may also be executed while the vehicle 10 is stopped.

[0131] In addition, in the aforementioned embodiment, when a dedicated motor for starting the engine 12, namely a starter, is equipped on the vehicle 10, when the vehicle 10 is stopped with the MG speed Nm set to zero, for example, when starting based on the electric motor MG cannot be fully performed due to an extremely low outside air temperature, a starting method can be adopted in which the engine 12 is ignited after being started by the starter.

[0132] In the above-mentioned embodiment, a planetary gear type automatic transmission is exemplified as the automatic transmission 24, but the automatic transmission 24 is not limited to this form. The automatic transmission 24 may be a synchromesh type parallel 2-axis automatic transmission including a known DCT (Dual Clutch Transmission), a known belt-type continuously variable transmission, or the like.

[0133] In addition, in the aforementioned embodiment, the vehicle 10 is an AWD vehicle based on a 2WD vehicle of FR mode, and is a parallel hybrid vehicle in which the driving force from the engine 12 and the electric motor MG is transmitted to the rear wheels 16, etc., but it is not limited to this mode. For example, even an AWD vehicle based on a 2WD vehicle of FF (front engine front wheel drive) mode, a hybrid vehicle equipped with a known electric continuously variable transmission, a series hybrid vehicle in which the driving force from the electric motor driven by the power of the generator driven by the power of the engine and / or the electric power of the battery is transmitted to the drive wheels, etc., can also be applied to the present invention. Alternatively, in the above-mentioned series hybrid vehicles, there is also a case where an automatic transmission is not provided.

[0134] In addition, in the above-mentioned embodiment, the AWD mode is not limited to the mode including the transfer case 26 and the ADD mechanism 37. For example, the AWD mode may be an AWD mode that switches between the 2WD mode and the AWD mode without the ADD mechanism 37. Alternatively, the transfer case 26 may be an AWD mode that switches between the 2WD mode and the AWD mode without the auxiliary transmission 106 and without the switching between the high gear stage GSH and the low gear stage GSL. In this case, the MG idle speed control that switches between the high gear stage GSH and the low gear stage GSL is not executed.

[0135] In addition, in the above-mentioned embodiment, the torque converter 22 is used as the fluid transmission device, but it is not limited to this method. For example, as the fluid transmission device, other fluid transmission devices such as a hydraulic coupling without a torque amplification function may be used instead of the torque converter 22. Alternatively, the fluid transmission device is not necessarily provided, and it may be replaced by a clutch for starting, for example.

[0136] The above-described content is merely one embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

Claims

1. A control device (90) for a hybrid vehicle (10), the hybrid vehicle (10) comprising an engine (12), a motor (MG), and a driving force distribution device (26) for distributing driving force to main driving wheels (16) and auxiliary driving wheels (14), The control device (90) of the hybrid vehicle (10) is characterized by comprising: An engine control unit (92a) for controlling the operating state of the engine (12); as well as a driving mode control unit (96) for controlling the driving of the hybrid vehicle (10) to realize a driving mode selected by a driver, The driving modes include a main drive wheel driving mode in which the driving force is distributed only to the main drive wheel (16) and an all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14). When the all-wheel drive mode is selected in the main drive wheel drive mode when the engine (12) is in a stopped state, the engine control unit (92a) maintains the stopped state of the engine (12) until the switching from the main drive wheel drive mode to the all-wheel drive mode by the driving mode control unit (96) is completed, and starts the engine (12) after the driver performs a predetermined operation for driving the hybrid vehicle (10). The predetermined operation is an acceleration requesting operation to increase the driving force.

2. The control device (90) of the hybrid vehicle (10) according to claim 1, characterized in that: The all-wheel drive mode is a driving mode for controlling the operating state of the engine (12) in such a manner as to increase the ratio of the driving time of the engine (12) to the operating time of the hybrid vehicle (10), i.e., the driving ratio (Reng) of the engine (12), compared with the main drive wheel drive mode.

3. The control device (90) of the hybrid vehicle (10) according to claim 1 or 2, characterized in that: When the all-wheel drive mode is selected in the main drive wheel drive mode when the hybrid vehicle (10) is stopped, the engine control unit (92a) maintains the stopped state of the engine (12) when performing a switching operation from a state in which the vehicle power transmission device (18) for transmitting the driving force cannot transmit the driving force to a state in which the vehicle power transmission device (18) is selected to transmit the driving force. When the acceleration request operation is performed after the switching operation, the engine (12) is started.

4. The control device (90) of the hybrid vehicle (10) according to claim 1 or 2, characterized in that: The invention also includes a motor control unit (92b) which outputs a predetermined torque for generating a creep phenomenon from the motor (MG) when the engine (12) is set to a stopped state when switching from the main drive wheel drive mode to the all-wheel drive mode.

5. The control device (90) of the hybrid vehicle (10) according to claim 4, characterized in that: When the main drive wheel drive mode is selected in the all-wheel drive mode when the predetermined torque is output from the electric motor (MG), the electric motor control unit (92b) reduces the output torque of the electric motor (MG) from the predetermined torque to zero after a predetermined time has passed since the switching from the all-wheel drive mode to the main drive wheel drive mode by the driving mode control unit (96) is completed.

6. The control device (90) of the hybrid vehicle (10) according to claim 5, characterized in that: When the vehicle power transmission device (18) transmitting the driving force is in a non-driving position where the driving force cannot be transmitted and the all-wheel drive mode is switched to the main drive wheel drive mode, the motor control unit (92b) reduces the output torque of the motor (MG).

7. The control device (90) of the hybrid vehicle (10) according to claim 1 or 2, characterized in that: The all-wheel drive mode includes a low-speed all-wheel drive mode in which a transmission (106) provided in the driving force distribution device (26) selectively forms a low-speed range and a high-speed range by operation of a meshing clutch and is set to the low-speed range, and a high-speed all-wheel drive mode in which the transmission (106) is set to the high-speed range. The main drive wheel driving mode is a high-speed main drive wheel driving mode in which the transmission (106) is set to the high-speed range, The control device (90) of the hybrid vehicle (10) further includes a motor control unit (92b) which, when the hybrid vehicle (10) is stopped and the engine (12) is set to a stopped state when switching from the high-speed main drive wheel drive mode to the high-speed all-wheel drive mode, outputs a predetermined torque from the motor (MG) to generate a creep phenomenon.

8. The control device (90) of the hybrid vehicle (10) according to claim 7, characterized in that: When the high-speed all-wheel drive mode is selected during control in the high-speed main drive wheel drive mode when both the engine (12) and the electric motor (MG) are set to a stopped state, the electric motor control unit (92b) outputs the predetermined torque from the electric motor (MG).

9. The control device (90) of the hybrid vehicle (10) according to claim 1 or 2, characterized in that: The engine control unit (92a) allows intermittent operation of the engine (12) by switching between a running state and a stopped state in the main drive wheel drive mode, and prohibits switching of the engine (12) from a running state to a stopped state in the all-wheel drive mode.

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