Control device for hybrid vehicle

Abstract

The present invention relates to a control device for a hybrid vehicle. When a low-speed all-wheel drive mode is selected, it is not easy to cause discomfort to the driver. In a high-speed all-wheel drive mode when the engine is stopped and a vehicle power transmission device is set to a non-driving position, when the low-speed all-wheel drive mode is selected, the engine is kept stopped before the switch from the high-speed all-wheel drive mode to the low-speed all-wheel drive mode is completed, and the engine is started after the switch to the low-speed all-wheel drive mode is completed, thereby avoiding the switching to the low-speed all-wheel drive mode and the engine starting at the same time, and the engine is started while preventing the generation of impact. As a result, when the low-speed 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, a driving force distribution device for distributing driving force to a main driving wheel and a secondary driving wheel, and a transmission provided in the driving force distribution device and selectively forming a low gear and a high gear. For example, the driving device of a hybrid vehicle described in Patent Document 1 is such a device. Patent Document 1 discloses that: as driving modes selected by the driver, there are a first mode and a second mode, and the second mode, compared with the first mode, places more emphasis on energy efficiency than on power performance; in addition, when the driver selects the second mode, the engine is started when the engine is in a stopped state. In addition, in Patent Document 1, as a second mode, a transfer case low driving mode in which the transmission in the transfer case as the driving force distribution device is set to a low gear and the vehicle is driven is exemplified.

[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, when the low-speed all-wheel drive mode is selected, in which the transmission provided in the driving force distribution device is set to the low gear stage, the driver may not necessarily intend to start the engine. Therefore, if the engine is started immediately when the low-speed all-wheel drive mode is selected, it may cause discomfort to the driver. Alternatively, if the engine is started immediately when the low-speed all-wheel drive mode is selected, it is possible that the switch to the low-speed all-wheel drive mode and the engine start are performed at the same time. Therefore, there is a concern that the hybrid vehicle will cause shock and cause discomfort to the driver.

[0008] The present invention has been made under the above circumstances, 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 a low-range all-wheel drive mode is selected.

[0009] Solutions for solving problems

[0010] As the gist of the first invention, (a) a control device for a hybrid vehicle, the hybrid vehicle comprises an engine, an electric motor, a driving force distribution device for distributing driving force to a main drive wheel and a secondary drive wheel, and a transmission provided on the driving force distribution device and selectively forming a low gear stage and a high gear stage, wherein the control device for the hybrid vehicle comprises: (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, and (d) an all-wheel drive mode for driving by distributing the driving force to both the main drive wheel and the secondary drive wheel. The mode includes a low-speed all-wheel drive mode in which the transmission is set to the low gear section and a high-speed all-wheel drive mode in which the transmission is set to the high gear section, and (e) in the high-speed all-wheel drive mode when the engine is in a stopped state and the vehicle power transmission device for transmitting the driving force is set to a non-driving position in which the driving force cannot be transmitted, when the low-speed all-wheel drive mode is selected, the engine control unit maintains the stopped state of the engine before the switching from the high-speed all-wheel drive mode to the low-speed all-wheel drive mode performed by the driving mode control unit is completed, and starts the engine after the switching to the low-speed all-wheel drive mode is completed.

[0011] In addition, according to the second invention, in the control device of the hybrid vehicle described in the first invention, after the driver performs a switching operation from selecting the non-driving position state of the vehicle power transmission device to selecting the driving position state capable of transmitting the driving force of the vehicle power transmission device, the engine control unit starts the engine.

[0012] In addition, according to the third invention, in the control device of the hybrid vehicle described in the first invention, the engine control unit starts the engine after the driver performs a switching operation from selecting the non-driving position state of the vehicle power transmission device to selecting the driving position state capable of transmitting the driving force of the vehicle power transmission device and an acceleration request operation to increase the driving force after the switching operation.

[0013] According to a fourth invention, in the control device for the hybrid vehicle described in the second invention or the third invention, the engine control unit does not start starting the engine during the transition of the vehicle power transmission device from the non-driving position to the driving position accompanying the switching operation.

[0014] In addition, the fifth invention is a control device for the hybrid vehicle described in the first invention, which further includes: a motor control unit, which outputs a predetermined torque that produces a creep phenomenon from the motor in the high-speed all-wheel drive mode when the engine is set to a stopped state, and in the state where the predetermined torque is output from the motor, the driving mode control unit operates the meshing clutch of the transmission to switch the transmission from the high-speed range to the low-speed range, thereby performing a switch from the high-speed all-wheel drive mode to the low-speed all-wheel drive mode while maintaining the stopped state of the engine.

[0015] According to a sixth aspect of the present invention, in the hybrid vehicle control device according to the first aspect of the present invention, the engine control unit prohibits switching of the engine from a running state to a stopped state in each of the high all-wheel drive mode and the low all-wheel drive mode.

[0016] In addition, the 7th invention is a control device for the hybrid vehicle described in the 1st invention, as a main drive wheel drive mode for driving by distributing the drive force only to the main drive wheels, the driving mode includes a high-speed main drive wheel drive mode in which the transmission is set to the high-speed range, and when the low-speed all-wheel drive mode is selected in the high-speed main drive wheel drive mode when the engine is set to a stopped state, the driving mode control unit does not execute the switching from the high-speed main drive wheel drive mode to the low-speed all-wheel drive mode, and executes the switching from the high-speed main drive wheel drive mode to the high-speed all-wheel drive mode while maintaining the stopped state of the engine.

[0017] In addition, the 8th invention is based on the control device of the hybrid vehicle described in the 7th invention, and also includes a notification control unit. When the low-range all-wheel drive mode is selected in the high-range main drive wheel drive mode, the notification control unit notifies the driver that the switch to the high-range all-wheel drive mode has been executed and prompts the driver to switch from selecting the low-range all-wheel drive mode to selecting the high-range all-wheel drive mode.

[0018] Effects of the Invention

[0019] According to the first invention, when the low-speed all-wheel drive mode is selected in the high-speed all-wheel drive mode when the engine is stopped and the vehicle power transmission device is set to the non-driving position, the engine is kept stopped until the switching from the high-speed all-wheel drive mode to the low-speed all-wheel drive mode is completed, and the engine is started after the switching to the low-speed all-wheel drive mode is completed, thereby avoiding the switching to the low-speed all-wheel drive mode and the engine starting being performed simultaneously, and the engine is started while preventing the occurrence of shock. As a result, when the low-speed all-wheel drive mode is selected, it is possible to prevent the driver from feeling uncomfortable.

[0020] In addition, according to the second invention, the engine is started after the driver performs a switching operation from the state of selecting the non-driving position of the vehicle power transmission device to the state of selecting the driving position. Therefore, starting the engine based on the driver's operation related to the engine start can make it less likely to cause discomfort to the driver. In addition, the engine can be started before an operation such as an acceleration request operation to actually drive the hybrid vehicle, thereby improving the drivability.

[0021] In addition, according to the third invention, the engine is started after the driver performs a switching operation from the state of selecting the non-driving position of the vehicle power transmission device to the state of selecting the driving position and an acceleration request operation to increase the driving force after the switching operation. Therefore, the engine is started based on the driver's operation related to the engine start, which can make it less likely to cause discomfort to the driver. In addition, before the operation of actually driving the hybrid vehicle is performed, the engine is kept in a stopped state, and energy efficiency is improved.

[0022] In addition, according to the fourth invention, in the transition of the vehicle power transmission device from the non-driving position to the driving position accompanied by the switching operation from the state of selecting the non-driving position of the vehicle power transmission device to the state of selecting the driving position, the engine start is not initiated, thereby avoiding the simultaneous execution of the switching of the vehicle power transmission device from the non-driving position to the driving position and the engine start, preventing the occurrence of impact.

[0023] In addition, according to the fifth invention, when a predetermined torque that generates creep phenomenon is output from the electric motor, the meshing clutch of the transmission is operated, thereby performing a switch from the high-speed all-wheel drive mode to the low-speed all-wheel drive mode while maintaining the engine in a stopped state. Therefore, the rotation required for the operation of the meshing clutch can be easily obtained by the rotation of the electric motor, and the switch to the low-speed all-wheel drive mode can be reliably performed.

[0024] Furthermore, according to the sixth invention, the switching of the engine from the running state to the stopped state is prohibited in the high-speed all-wheel drive mode and the low-speed all-wheel drive mode, so that the responsiveness of the driving force can be easily ensured in the all-wheel drive mode. Alternatively, the busy feeling caused by the engine being switched to the running state immediately after being set to the stopped state can be prevented.

[0025] In addition, according to the seventh invention, when the low-range all-wheel drive mode is selected in the high-range main drive wheel drive mode when the engine is set to a stopped state, the switch to the low-range all-wheel drive mode is not executed, and the switch to the high-range all-wheel drive mode is executed while maintaining the stopped state of the engine, thereby avoiding the simultaneous execution of the switching of the transmission from the high gear to the low gear and the switching from the main drive wheel drive mode to the all-wheel drive mode, thereby preventing the occurrence of impact.

[0026] Furthermore, according to the eighth invention, when the low-range all-wheel drive mode is selected in the high-range main drive wheel drive mode, the driver is notified that the switch to the high-range all-wheel drive mode is executed and the switch from the low-range all-wheel drive mode to the high-range all-wheel drive mode is prompted, so that the driver can be prompted to make a selection that matches the high-range all-wheel drive mode actually controlled. As a result, the driver is prompted to perform an operation to select the appropriate low-range all-wheel drive mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 2 Yes Description Figure 1 Schematic diagram of the structure of the transfer case.

[0029] Figure 3 This 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 low range AWD mode is selected.

[0030] 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 for preventing the driver from feeling uncomfortable when the low-range AWD mode is selected, and is Figure 3 Flowcharts of different embodiments.

[0031] Description of Reference Numerals

[0032] 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, 98: notification control unit, 106: subtransmission (transmission), 120: meshing clutch for subtransmission (meshing clutch), MG: electric motor. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0034] [Example 1]

[0035] 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.

[0036] 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 this 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 serves as a drive wheel in both 2WD driving and AWD driving. In addition, the front wheel 14 is a secondary drive wheel that serves as a driven wheel in 2WD driving and as a drive wheel in AWD driving. 2WD driving is driving in a 2WD state in which the driving force from the engine 12 or the like 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 or the like is transmitted to the rear wheel 16 and the front wheel 14.

[0037] 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 including a throttle actuator, a fuel injection device, an ignition device, etc. provided in the vehicle 10, thereby controlling an engine torque Te which is an output torque of the engine 12.

[0038] The electric motor MG is a rotating electrical machine having the function of an engine that generates mechanical power using electric power and the function of a generator that generates electric power using 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 transfers electric power to and from the electric motor MG. The electric motor MG controls the inverter 52 by using an electronic control device 90 described later, thereby controlling the MG torque Tm, which is the output torque of the electric motor MG. For example, when the rotation direction of the electric motor MG is positive rotation, that is, the same rotation direction as the engine 12 when driving, the MG torque Tm is a power running torque in a positive torque on the acceleration side, and a regenerative torque in a negative torque on the deceleration side. In the case where no special distinction is made, the electric power is also synonymous with electric energy. In the case where no special distinction is made, the power is also synonymous with torque and force.

[0039] 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 wheel drive shafts 38. In the power transmission device 18, the K0 clutch 20, the torque converter 22, and the automatic transmission 24 are provided in a housing 40, which is 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, and a motor connecting shaft 44 connecting the K0 clutch 20 and the torque converter 22 in the housing 40.

[0040] 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 as the input rotating member of the automatic transmission 24. The transfer case 26 is connected to the transmission output shaft 48 as the output rotating member of the automatic transmission 24.

[0041] The electric motor MG is connected to the electric motor connecting shaft 44 in a power-transmittable manner in the housing 40. That is, 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.

[0042] 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 .

[0043] 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.

[0044] 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 torque capacities, i.e., CB torques Tcb, respectively, 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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 2 In 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, etc., which are arranged on a common second axis CS2, in the transfer case 100. In addition, the transfer case 26 includes a chain 116 that connects the drive gear 110 and the driven gear 114.

[0049] 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 relative rotation with respect to the first output shaft 104 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.

[0050] The auxiliary transmission 106 includes a planetary gear device 118 and an auxiliary transmission meshing clutch 120. The auxiliary transmission meshing clutch 120 includes a high-side meshing mechanism 122 for establishing a high gear stage GSH, which is a gear stage on the high speed side with a small gear ratio, and a low-side meshing mechanism 124 for establishing a low gear stage GSL, which is a gear stage on the low speed side with a large gear ratio. 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 gear stage GSL and a high gear stage GSH by operating the auxiliary transmission meshing clutch 120, which is 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.

[0051] The meshing clutch 108 for power distribution is an engagement device for selectively switching between allowing the relative rotation of the drive gear 110 relative to the first output shaft 104 and preventing 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 into 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 into an engaged 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.

[0052] 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.

[0053] 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 is transmitted to the front wheels 14 via the front wheel 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 is transmitted to the rear wheels 16 via the rear drive shaft 32. As a result, the vehicle 10 is in the AWD state.

[0054] 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.

[0055] In the vehicle 10, when the K0 clutch 20 is engaged, the engine 12 and the torque converter 22 are connected so that power can be transmitted. On the other hand, when the K0 clutch 20 is released, 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.

[0056] 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 wheels 16 side and the front wheels 14 side through the transfer case 26.

[0057] 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.

[0058] The vehicle 10 further includes an electronic control device 90 including a control device of the vehicle 10 associated with the 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.

[0059] Various signals based on detection values ​​obtained by various sensors provided in the vehicle 10 (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 gear position sensor 80, a drive switching dial switch 81, a battery sensor 82, an oil temperature sensor 83, etc.) are respectively provided 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 speeds of the front wheels 14 and the rear wheels 16, etc.) Nr, the accelerator operation amount indicating the magnitude of the driver's acceleration operation, i.e., the accelerator opening θacc, the electronic throttle opening θth, the brake-on signal Bon indicating the state of the brake pedal for operating the wheel brakes being operated by the driver, the longitudinal acceleration Gx and the left-right acceleration Gy of the vehicle 10, the yaw rate Ryaw, the shift operation position POSsh indicating the operation position of the shift lever 66 of the vehicle 10, the dial operation position POSdl indicating the operation position of the drive switching dial switch 81, 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, i.e., the working oil temperature THoil, etc.).

[0060] 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 gear of the power transmission device 18, particularly the automatic transmission 24, and includes, for example, P, R, N, and D operating positions.

[0061] The P operation position is a parking operation position for selecting a parking position (=P position) as a parking position of the automatic transmission 24. The P position of the automatic transmission 24 is a 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 a driving force, and is achieved by, for example, setting all the engagement devices CB to a released state to block the power transmission of the automatic transmission 24. 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 for selecting a reverse travel position (=R position) as a reverse travel position of the automatic transmission 24. The R position of the automatic transmission 24 is a position of the automatic transmission 24 for enabling the vehicle 10 to travel in reverse. The N operating gear position is a neutral operating gear position for selecting the neutral gear position (=N gear position) as the neutral position of the automatic transmission 24. The N gear position of the automatic transmission 24 is a 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 driving gear position (=D gear position) selected as the forward driving position of the automatic transmission 24. The D gear position of the automatic transmission 24 is a gear position of the automatic transmission 24 for executing the automatic speed change control of the automatic transmission 24 so that the vehicle 10 can move 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.

[0062] 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 in the high gear stage 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, basically, the auxiliary transmission 106 is set to the high gear stage GSH. That is, in the present embodiment, the 2WD mode is a 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 in the high gear stage 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 in the low gear stage 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, i.e., the AWD mode, includes a low-speed AWD mode and a 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, a seesaw type, etc.

[0063] 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 pressure control command signal Scb for controlling the engagement device CB, a K0 hydraulic pressure control command signal Sk0 for controlling the K0 clutch 20, an EOP control command signal Seop for controlling the EOP 62, an information notification control command signal Sinf for notifying the driver of various information, 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 based on 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 information notification device 68, the shift actuator 126, etc.).

[0064] The information notification device 68 is a device that notifies the driver of various information when, for example, an operation of a control request that is not permitted is performed in the vehicle 10 or a function related to the driving of the vehicle 10 is degraded. The information notification device 68 is, for example, a display device such as a monitor, a display, or a warning light, and / or a sound output device such as a speaker or a buzzer.

[0065] 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, a driving mode control unit 96 as a driving mode control means, and a notification control unit 98 as a notification control means, in order to realize various controls of the vehicle 10 .

[0066] 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.

[0067] The hybrid control unit 92 calculates the driver's drive request for the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to the drive request map. The drive request map is a relationship that is obtained and stored in advance through experiments or design, that is, a predetermined relationship. The drive request is, for example, the requested drive torque Trdem of the drive wheels (rear wheels 16, front wheels 14). In other words, the requested drive torque Trdem [Nm] is the requested drive power Prdem [W] at the vehicle speed V at this time. As the drive request, the requested drive force Frdem [N] of the drive wheels, the requested AT output torque of the transmission output shaft 48, etc. can also be used. In the calculation of the drive request, the AT output speed No, etc. can also be used instead of the vehicle speed V.

[0068] 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, i.e., the engine power Pe, for outputting 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 for outputting the MG torque Tm at the current MG speed Nm.

[0069] The chargeable power Win of the battery 54 is the maximum power that can be inputted to limit the input power of the battery 54, indicating the input limit of the battery 54. The dischargeable power Wout of the battery 54 is the maximum power that can be outputted to limit the output power of the battery 54, indicating the output limit of the battery 54. The chargeable power Win and the dischargeable power Wout of the battery 54 are calculated, for example, by the electronic control unit 90 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, for example, by the electronic control unit 90 based on the battery charge and discharge current Ibat and the battery voltage Vbat.

[0070] The hybrid control unit 92 sets the driving mode to the motor driving (=EV driving) mode when the requested 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 drives only with 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 power driving (=HV driving) mode, when the requested 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 drives at least with 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 requested 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 determining that the engine 12 needs to be forcibly started 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 requested drive torque Trdem, etc.

[0071] 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 requested drive torque Trdem is larger than the range provided by the output of the motor MG alone, whether preheating of the engine 12 is required, or whether the charge state value SOC of the battery 54 is less than the engine start threshold value SOCengf.

[0072] 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 the required starting torque Tcrn.

[0073] 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 torque Tcrn for starting, in response to the switching of the K0 clutch 20 to the engaged state by the hydraulic control unit 94.

[0074] 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.

[0075] When the engine 12 is started during EV driving, the motor control unit 92b generates the MG torque Tm for EV driving, i.e., the MG torque Tm of the driving torque Tr, and also outputs the MG torque Tm of the required torque Tcrn for starting from the motor MG. Therefore, during EV driving, in preparation for starting the engine 12, it is necessary to ensure the torque of the required torque Tcrn for starting. Therefore, the range in which the requested driving torque Trdem is provided only by the output of the motor MG is the torque range after the required torque Tcrn for starting 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.

[0076] 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 requested drive torque Trdem is within the range that can be 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.

[0077] When determining that there is a request to stop the engine 12, the engine control unit 92a outputs an 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 an engine control command signal Se for controlling the engine 12 to stop the operation of the engine 12 to the engine control device 50.

[0078] 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 .

[0079] 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 .

[0080] The hydraulic control unit 94 uses, for example, a shift map as a predetermined relationship to perform a shift judgment of the automatic transmission 24, and outputs a 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 judging 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.

[0081] 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 high 2WD mode, a high AWD mode, and a low AWD mode.

[0082] When the high-speed 2WD mode is selected by 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 gear 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.

[0083] When the high-speed AWD mode is selected by 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 gear 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.

[0084] When the low-speed AWD mode is selected by 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 subtransmission 106 to the low gear 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.

[0085] In switching between the low-range AWD mode and the high-range AWD mode, it is necessary to switch the auxiliary transmission meshing clutch 120 in the auxiliary transmission 106. In switching the auxiliary transmission meshing clutch 120, the input shaft 102 and the like need to rotate to a certain extent. In switching between the low-range AWD mode and the high-range AWD mode, it is necessary to set the engine 12 to a running state or rotate the motor MG. In the AWD mode, if the engine 12 is in a stopped state, the motor MG is set to a rotating state.

[0086] In each of the low-range AWD mode and the high-range AWD mode when the engine 12 is set to a stopped state, the motor control unit 92b performs, for example, idle speed control of the motor MG, i.e., MG idle speed control. The MG idle speed control is a control to keep the motor MG in an idle state by maintaining the MG speed Nm at, for example, a predetermined idle speed of the motor MG, i.e., the MG idle speed. The MG idle speed control is a control as follows: for example, when the accelerator is disconnected in the stopped state of the engine 12, by disconnecting 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 maintaining the accelerator disconnected. The predetermined torque is a creep torque for, for example, performing a brake disconnection operation in a stopped state of the vehicle and causing the vehicle 10 to travel in a so-called creep travel while maintaining the accelerator disconnected state.

[0087] For example, when an operation is performed in the vehicle 10 that requests an unauthorized control, or when a function related to the driving of the vehicle 10 is reduced, the notification control unit 98 outputs an information notification control instruction signal Sinf to the information notification device 68 to notify the driver that the current operation is invalid, or to prompt the driver to perform other operations, or to notify the current status of the vehicle 10.

[0088] Here, in the low-range AWD mode, a larger driving force Fr is likely to be required than in the high-range 2WD mode and the high-range AWD mode. In the HV driving mode, since the engine 12 is in the running state, a larger driving force Fr is likely to be obtained than in the EV driving mode. Therefore, when the low-range AWD mode is selected with the engine 12 stopped, it is considered to start the engine 12 and set it to the running state.

[0089] In addition, when the driver selects the low AWD mode, the driver may not necessarily intend to start the engine 12. For example, when the automatic transmission 24 is set to the non-driving position, the driver is more likely to not intend to start the engine 12 than when the automatic transmission 24 is set to the driving position. Alternatively, if the engine 12 is started immediately when the low AWD mode is selected, a shock may be generated due to the simultaneous execution of the switch to the low AWD mode and the engine start. It is desirable that when the low AWD mode is selected, the driver is less likely to feel uncomfortable.

[0090] Therefore, when the engine 12 is stopped and the driving mode is the high 2WD mode or the high AWD mode, when the low AWD mode is selected, the engine control unit 92a does not immediately start the engine 12. When the low AWD mode is selected in the high AWD mode, the engine control unit 92a starts the engine 12 after completing the switch to the low AWD mode. In addition, when the driver performs an operation that does not easily feel uncomfortable even if the engine 12 is started after the switch to the low AWD mode is completed, the engine control unit 92a starts the engine 12.

[0091] That is, when the low AWD mode is selected in the high AWD mode when the engine 12 is stopped and the automatic transmission 24 is set to the non-driving position, the engine control unit 92a maintains the stopped state of the engine 12 until the driving mode control unit 96 completes the switching from the high AWD mode to the low AWD mode, and after the switching to the low AWD mode is completed, the engine control unit 92a starts the engine 12. In addition to completing the switching to the low AWD mode, the engine control unit 92a also starts the engine 12 after the driver performs a predetermined operation AMf for driving the vehicle 10.

[0092] The predetermined operation AMf is, for example, a switching operation from a state where the non-driving position of the automatic transmission 24 is selected to a state where the driving position of the automatic transmission 24 is selected. The state where the non-driving position of the automatic transmission 24 is selected is a state where the shift operation position POSsh is set to the P operating position or the N operating position. The state where the driving position of the automatic transmission 24 is selected is a state where the shift operation position POSsh is set to the D operating position or the R operating position. That is, the switching operation is an N(P)→D(R) operation.

[0093] Alternatively, the predetermined operation AMf is, for example, an N(P)→D(R) operation and an acceleration request operation for increasing the driving force Fr after the N(P)→D(R) operation. The acceleration request operation for increasing the driving force Fr is, for example, an accelerator-on operation for increasing the requested driving force Frdem.

[0094] Specifically, the engine control unit 92a determines whether the engine 12 is in a stopped state. The hydraulic control unit 94 determines whether the automatic transmission 24 is set to a non-driving position.

[0095] When the engine control unit 92a determines that the engine 12 is stopped and the hydraulic control unit 94 determines that the automatic transmission 24 is in the non-driving position, the driving mode control unit 96 determines whether the driving mode is the high AWD mode. When the driving mode control unit 96 determines that the driving mode is the high AWD mode, it determines whether the low AWD mode is selected based on the dial operation shift position POSd1.

[0096] When the driving mode control unit 96 determines that the low-range AWD mode is selected, the motor control unit 92b operates the auxiliary transmission meshing clutch 120 while the motor MG is outputting creep torque, and switches the auxiliary transmission 106 from the high gear stage GSH to the low gear stage GSL, thereby switching from the high-range AWD mode to the low-range AWD mode while maintaining the stopped state of the engine 12. The driving mode control unit 96 determines whether the switching from the high-range AWD mode to the low-range AWD mode is completed.

[0097] When the travel mode control unit 96 determines that the switch from the high AWD mode to the low AWD mode has been completed, the hydraulic control unit 94 determines whether an N(P)→D(R) operation as a predetermined operation AMf has been performed.

[0098] When the hydraulic control unit 94 determines that the N(P)→D(R) operation has been performed, the hydraulic control unit 94 switches the automatic transmission 24 from the non-driving position to the driving position according to the N(P)→D(R) operation. The hydraulic control unit 94 determines whether the switching of the automatic transmission 24 from the non-driving position to the driving position has been completed.

[0099] When the hydraulic control unit 94 determines that the switching of the automatic transmission 24 from the non-driving position to the driving position is completed, the engine control unit 92a starts the engine 12. That is, the engine control unit 92a does not start the engine 12 during the transition of the automatic transmission 24 from the non-driving position to the driving position accompanying the N(P)→D(R) operation.

[0100] The high-speed 2WD mode gives priority to energy efficiency compared to the AWD mode. Therefore, in the high-speed 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-speed 2WD mode. Therefore, in the AWD mode, it is desirable to prohibit the intermittent operation of the engine without making the engine 12 stopped after the engine 12 is temporarily set to the running state. The engine control unit 92a prohibits the switching of the engine 12 from the running state to the stopped state in the high-speed AWD mode and the low-speed AWD mode respectively.

[0101] 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 less likely to give the driver a sense of discomfort when the low range AWD mode is selected, and is executed repeatedly, for example.

[0102] exist Figure 3In the routine, first, in step S10 corresponding to the function of the engine control unit 92a (hereinafter, the step is omitted), it is determined whether the engine 12 is in a stopped state. If the determination of S10 is negative, the routine is terminated. If the determination of S10 is positive, in S20 corresponding to the function of the hydraulic control unit 94, it is determined whether the automatic transmission 24 is set to a non-driving position. If the determination of S20 is negative, the 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 driving mode is a high-speed AWD mode. If the determination of S30 is negative, the routine is terminated. If the determination of S30 is positive, in S40 corresponding to the function of the driving mode control unit 96, it is determined whether the low-speed AWD mode is selected. If the determination of S40 is negative, the routine is terminated. In the case where the judgment of S40 is affirmative, in S50 corresponding to the function of the driving mode control unit 96, the switch from the high-speed AWD mode to the low-speed AWD mode is executed in the state where the creep torque is output from the electric 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-speed AWD mode to the low-speed AWD mode has been completed. In the case where the judgment of S60 is negative, the above-mentioned S50 is returned. In the case where the judgment of S60 is affirmative, in S70 corresponding to the function of the hydraulic control unit 94, it is determined whether the N(P)→D(R) operation as the predetermined operation AMf has been performed. In the case where the judgment of S70 is negative, the above-mentioned S40 is returned. In the case where the judgment of S70 is affirmative, in S80 corresponding to the function of the hydraulic control unit 94, the automatic transmission 24 is switched from the non-driving position to the driving position according to the N(P)→D(R) operation. Next, in S90 corresponding to the function of the hydraulic control unit 94, it is determined whether the switching of the automatic transmission 24 from the non-driving position to the driving position is completed. If the determination of S90 is negative, the process returns to the above-mentioned S80. If the determination of S90 is positive, in S100 corresponding to the function of the engine control unit 92a, the engine 12 is started. In addition, the intermittent operation of the engine is prohibited, and the switching of the engine 12 from the running state to the stopped state is prohibited.

[0103] As described above, according to the present embodiment, in the high AWD mode when the engine 12 is stopped and the automatic transmission 24 is set to the non-driving position, when the low AWD mode is selected, the stopped state of the engine 12 is maintained before the switch from the high AWD mode to the low AWD mode is completed, and the engine 12 is started after the switch to the low AWD mode is completed, thereby avoiding the switching to the low AWD mode and the engine starting being performed simultaneously, and the engine 12 is started while preventing the occurrence of shock. As a result, when the low AWD mode is selected, it is possible to prevent the driver from feeling uncomfortable.

[0104] In addition, according to the present embodiment, since the engine 12 is started after the driver performs the N(P)→D(R) operation, the engine 12 is started based on the driver's operation related to the engine start, which can reduce the driver's discomfort. In addition, the engine 12 can be started before the operation of actually driving the vehicle 10, such as the accelerator opening operation, to improve the drivability.

[0105] In addition, according to the present embodiment, the engine 12 is started after the driver performs the N(P)→D(R) operation and the acceleration request operation for increasing the driving force Fr after the N(P)→D(R) operation. Therefore, the engine 12 is started based on the driver's operation related to the engine start, which can make it less likely to give the driver a sense of discomfort. In addition, the engine 12 is kept stopped before the operation of actually driving the vehicle 10 is performed, and energy efficiency is improved.

[0106] In addition, according to the present embodiment, in the transition of the automatic transmission 24 switching from the non-driving position to the driving position accompanying the N(P)→D(R) operation, the starting of the engine 12 is not initiated, thereby avoiding the simultaneous execution of the switching of the automatic transmission 24 from the non-driving position to the driving position and the starting of the engine, thereby preventing the occurrence of shock.

[0107] In addition, according to the present embodiment, the sub-transmission clutch 120 is operated while the creep torque is output from the motor MG, thereby performing a switch from the high-speed AWD mode to the low-speed AWD mode while maintaining the stopped state of the engine 12. Therefore, it is easy to obtain the rotation required for the operation of the sub-transmission clutch 120 through the rotation of the motor MG, and the switch to the low-speed AWD mode can be reliably performed.

[0108] In addition, according to the present embodiment, the switching of the engine 12 from the running state to the stopped state is prohibited in the high-range AWD mode and the low-range AWD mode, so that the responsiveness of the driving force Fr is easily ensured in the AWD mode. Alternatively, the busy feeling caused by setting the engine 12 to the running state immediately after being set to the stopped state is prevented.

[0109] Next, other embodiments of the present invention will be described. In the following description, the same reference numerals are given to common parts among the embodiments, and description thereof will be omitted.

[0110] [Example 2]

[0111] In the aforementioned first embodiment, the case where the low-range AWD mode is selected in the high-range AWD mode is exemplified to explain the control action for making it less likely for the driver to feel uncomfortable when the low-range AWD mode is selected. In this embodiment, the case where the low-range AWD mode is selected in the high-range 2WD mode is explained. This embodiment is implemented on the basis of the aforementioned first embodiment.

[0112] In the switching from the high 2WD mode to the low AWD mode, it is necessary to switch from the high gear stage GSH to the low gear stage GSL and switch from the 2WD mode to the AWD mode of the auxiliary transmission 106. Therefore, when the low AWD mode is selected when the driving mode is the high 2WD mode, even if control is performed not to start the engine 12 immediately, there is a possibility that a shock will be generated due to the simultaneous execution of the switching to the low gear stage GSL and the switching to the AWD mode.

[0113] Therefore, when the low-range AWD mode is selected in the high-range 2WD mode when the engine 12 is set to a stopped state, the driving mode control unit 96 does not execute the switch from the high-range 2WD mode to the low-range AWD mode, but executes the switch from the high-range 2WD mode to the high-range AWD mode while maintaining the stopped state of the engine 12.

[0114] Specifically, 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 in the stopped state. When the driving mode is determined to be the high 2WD mode, the driving mode control unit 96 determines whether the low AWD mode is selected based on the dial operation shift position POSd1.

[0115] When the driving mode control unit 96 determines that the low AWD mode is selected, the driving mode control unit 96 switches from the high 2WD mode to the high AWD mode while maintaining the stopped state of the engine 12 .

[0116] When the low-range AWD mode is selected in the high-range 2WD mode, the notification control unit 98 outputs an information notification control command signal Sinf to the information notification device 68, which is used to notify the driver that a switch to the high-range AWD mode has been executed and to prompt a switch from selecting the low-range AWD mode to selecting the high-range AWD mode.

[0117] Figure 4This 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 making it less likely for the driver to feel uncomfortable when the low range AWD mode is selected, and is executed repeatedly, for example. Figure 4 is with Figure 3 Flowcharts of different embodiments.

[0118] exist Figure 4 In the routine, first, in S10b corresponding to the function of the engine control unit 92a, it is determined whether the engine 12 is in a stopped state. 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 driving mode control unit 96, it is determined whether the driving mode is the high-end 2WD mode. 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 low-end AWD 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 switch from the high-end 2WD mode to the high-end AWD mode is performed while maintaining the stopped state of the engine 12. Next, in S50b corresponding to the function of the notification control unit 98, the information notification device 68 notifies the driver that the switch to the high AWD mode has been executed and prompts the driver to switch from the low AWD mode to the high AWD mode.

[0119] As described above, according to the present embodiment, when the low-range AWD mode is selected in the high-range 2WD mode when the engine 12 is set to a stopped state, the switch to the low-range AWD mode is not executed, and the switch to the high-range AWD mode is executed while maintaining the stopped state of the engine 12, thereby avoiding the simultaneous execution of the switching of the auxiliary transmission 106 from the high gear stage GSH to the low gear stage GSL and the switching from the 2WD mode to the AWD mode, thereby preventing the occurrence of shock.

[0120] In addition, according to the present embodiment, when the low-range AWD mode is selected in the high-range 2WD mode, the driver is notified that the switch to the high-range AWD mode is executed and the switch from the low-range AWD mode to the high-range AWD mode is prompted, so that the driver can be prompted to make a selection that matches the high-range AWD mode actually controlled. As a result, the driver is prompted to perform an operation to select the appropriate low-range AWD mode.

[0121] 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.

[0122] For example, in the aforementioned embodiment 1, it may also be: Figure 3 In S70 of the flowchart, in addition to determining whether the N(P)→D(R) operation has been performed, it is also determined whether the acceleration request operation has been performed, thereby determining whether the predetermined operation AMf has been performed. Figure 3 In other words, S100 may be executed when the determination at S60 is affirmative. This can also avoid switching to the low range AWD mode and starting the engine at the same time.

[0123] In addition, in the aforementioned embodiment, when a dedicated motor for starting the engine 12, namely a starter, is provided in 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 temperature, a starting method can be adopted in which the engine 12 is ignited after being started by the starter.

[0124] In the above-mentioned embodiment, a planetary gear type automatic transmission is exemplified as the automatic transmission 24, but the present invention 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.

[0125] 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.

[0126] In addition, in the aforementioned embodiment, the AWD mode is not limited to the mode with the transfer case 26 and the ADD mechanism 37. For example, it is also possible to have an AWD mode that switches between the 2WD mode and the AWD mode without the ADD mechanism 37. Or, in the aforementioned embodiment 1, it is also possible to have an AWD mode that is always AWD without the 2WD mode. In addition, in the case of switching between the low gear stage GSL and the high gear stage GSH by the operation of the meshing clutch, the non-driving position of the automatic transmission 24 when the switching between the low gear stage GSL and the high gear stage GSH is executed is particularly the N gear position of the automatic transmission 24.

[0127] 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.

[0128] 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), an electric motor (MG), a driving force distribution device (26) for distributing driving force to a main driving wheel (16) and a secondary driving wheel (14), and a transmission (106) provided in the driving force distribution device (26) and selectively forming a low gear stage and a high gear stage, 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, As an all-wheel drive mode for driving by distributing the driving force to both the main drive wheel (16) and the auxiliary drive wheel (14), the driving mode includes a low-range all-wheel drive mode in which the transmission (106) is set to the low gear range and a high-range all-wheel drive mode in which the transmission (106) is set to the high gear range, When the low-speed all-wheel drive mode is selected in the high-speed all-wheel drive mode when the engine (12) is in a stopped state and the vehicle power transmission device (18) for transmitting the driving force is set to a non-driving position in which the driving force cannot be transmitted, the engine control unit (92a) maintains the stopped state of the engine (12) before the switching from the high-speed all-wheel drive mode to the low-speed all-wheel drive mode by the driving mode control unit (96) is completed, and starts the engine (12) after the switching to the low-speed all-wheel drive mode is completed. After the driver performs a switching operation from selecting the non-driving position of the vehicle power transmission device (18) to selecting the driving position capable of transmitting the driving force of the vehicle power transmission device (18), the engine control unit (92a) starts the engine (12).

2. The control device (90) of the hybrid vehicle (10) according to claim 1, characterized in that: In the transition of the vehicle power transmission device (18) from the non-driving position to the driving position accompanying the switching operation, the engine control unit (92a) does not start the engine (12).

3. The control device (90) of the hybrid vehicle (10) according to claim 1, characterized in that: The control device (90) of the hybrid vehicle (10) further includes a motor control unit (92b) which outputs a predetermined torque for generating a creep phenomenon from the motor (MG) in the high-speed all-wheel drive mode when the engine (12) is set to a stopped state. In a state where the predetermined torque is output from the electric motor (MG), the driving mode control unit (96) operates the meshing clutch (120) provided in the transmission (106) to switch the transmission (106) from the high gear to the low gear, thereby switching from the high gear all-wheel drive mode to the low gear all-wheel drive mode while maintaining the stopped state of the engine (12).

4. The control device (90) of the hybrid vehicle (10) according to claim 1, characterized in that: The engine control unit (92a) prohibits switching of the engine (12) from a running state to a stopped state in the high-speed all-wheel drive mode and the low-speed all-wheel drive mode.

5. The control device (90) of the hybrid vehicle (10) according to claim 1, characterized in that: As a main drive wheel driving mode for driving by distributing the driving force only to the main drive wheels (16), the driving mode includes a high-speed main drive wheel driving mode in which the transmission (106) is set to the high-speed range, When the low-range all-wheel drive mode is selected in the high-range main drive wheel drive mode when the engine (12) is set to a stopped state, the driving mode control unit (96) does not execute the switch from the high-range main drive wheel drive mode to the low-range all-wheel drive mode, and executes the switch from the high-range main drive wheel drive mode to the high-range all-wheel drive mode while maintaining the stopped state of the engine (12).

6. The control device (90) of the hybrid vehicle (10) according to claim 5, characterized in that: The control device (90) of the hybrid vehicle (10) further includes a notification control unit (98) which, when the low-range all-wheel drive mode is selected in the high-range main drive wheel drive mode, notifies the driver that a switch to the high-range all-wheel drive mode has been executed and prompts the driver to switch from selecting the low-range all-wheel drive mode to selecting the high-range all-wheel drive mode.

7. A control device (90) for a hybrid vehicle (10), the hybrid vehicle (10) comprising an engine (12), an electric motor (MG), a driving force distribution device (26) for distributing driving force to a main driving wheel (16) and a secondary driving wheel (14), and a transmission (106) provided in the driving force distribution device (26) and selectively forming a low gear stage and a high gear stage, 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, As an all-wheel drive mode for driving by distributing the driving force to both the main drive wheel (16) and the auxiliary drive wheel (14), the driving mode includes a low-range all-wheel drive mode in which the transmission (106) is set to the low gear range and a high-range all-wheel drive mode in which the transmission (106) is set to the high gear range, When the low-speed all-wheel drive mode is selected in the high-speed all-wheel drive mode when the engine (12) is in a stopped state and the vehicle power transmission device (18) for transmitting the driving force is set to a non-driving position in which the driving force cannot be transmitted, the engine control unit (92a) maintains the stopped state of the engine (12) before the switching from the high-speed all-wheel drive mode to the low-speed all-wheel drive mode by the driving mode control unit (96) is completed, and starts the engine (12) after the switching to the low-speed all-wheel drive mode is completed. After the driver performs a switching operation from selecting the non-driving position state of the vehicle power transmission device (18) to selecting the driving position state capable of transmitting the driving force of the vehicle power transmission device (18), and an acceleration request operation for increasing the driving force after the switching operation, the engine control unit (92a) starts the engine (12).

8. The control device (90) of the hybrid vehicle (10) according to claim 7, characterized in that: In the transition of the vehicle power transmission device (18) from the non-driving position to the driving position accompanying the switching operation, the engine control unit (92a) does not start the engine (12).

9. The control device (90) of the hybrid vehicle (10) according to claim 7, characterized in that: The control device (90) of the hybrid vehicle (10) further includes a motor control unit (92b) which outputs a predetermined torque for generating a creep phenomenon from the motor (MG) in the high-speed all-wheel drive mode when the engine (12) is set to a stopped state. In a state where the predetermined torque is output from the electric motor (MG), the driving mode control unit (96) operates the meshing clutch (120) provided in the transmission (106) to switch the transmission (106) from the high gear to the low gear, thereby switching from the high gear all-wheel drive mode to the low gear all-wheel drive mode while maintaining the stopped state of the engine (12).

10. The control device (90) of the hybrid vehicle (10) according to claim 7, characterized in that: The engine control unit (92a) prohibits switching of the engine (12) from a running state to a stopped state in the high-speed all-wheel drive mode and the low-speed all-wheel drive mode.

11. The control device (90) of the hybrid vehicle (10) according to claim 7, characterized in that: As a main drive wheel driving mode for driving by distributing the driving force only to the main drive wheels (16), the driving mode includes a high-speed main drive wheel driving mode in which the transmission (106) is set to the high-speed range, When the low-range all-wheel drive mode is selected in the high-range main drive wheel drive mode when the engine (12) is set to a stopped state, the driving mode control unit (96) does not execute the switch from the high-range main drive wheel drive mode to the low-range all-wheel drive mode, and executes the switch from the high-range main drive wheel drive mode to the high-range all-wheel drive mode while maintaining the stopped state of the engine (12).

12. The control device (90) of the hybrid vehicle (10) according to claim 11, characterized in that: The control device (90) of the hybrid vehicle (10) further includes a notification control unit (98) which, when the low-range all-wheel drive mode is selected in the high-range main drive wheel drive mode, notifies the driver that a switch to the high-range all-wheel drive mode has been executed and prompts the driver to switch from selecting the low-range all-wheel drive mode to selecting the high-range all-wheel drive mode.

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