Hybrid vehicle control device

Abstract

The present invention provides a control device for a hybrid vehicle. It suppresses deterioration in drivability and improves energy efficiency. The engine operating conditions for starting or stopping the engine are predetermined so that the engine's operating ratio is higher when towing mode is selected than when all-wheel drive mode is selected. This makes it easier to ensure sufficient driving force when towing mode is selected, and easier to improve energy efficiency when all-wheel drive mode is selected. Specifically, the engine is started or stopped based on whether towing mode, which definitely requires high driving force during launch or acceleration, or all-wheel drive mode, which does not necessarily require high driving force. This allows for suppressing deterioration in drivability and improving energy efficiency.

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] Control devices for hybrid vehicles equipped with an engine and an electric motor are widely known. For example, the drive device for a hybrid vehicle described in Patent Document 1 corresponds thereto. Patent Document 1 discloses a first mode and a second mode that prioritizes power performance over energy efficiency as driving modes, and that when the driving mode is switched from the first mode to the second mode, the engine is started when the engine is stopped. Patent Document 1 also cites a low-speed driving mode in which the transmission provided in the transmission device that distributes power to the front and rear drive wheels is shifted to a low gear position, and a towing driving mode in which the vehicle is driven by towing another vehicle.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-179780 Summary of the Invention

[0006] However, in towing mode, where a vehicle is towed by a towing vehicle, or in all-wheel drive mode, where driving force is distributed to both the main and auxiliary drive wheels, uniformly setting engine operating conditions for starting or stopping the engine to ensure sufficient driving force and improve drivability can increase the engine's operating rate unnecessarily, potentially degrading energy efficiency. For example, in towing mode, high driving force is definitely required for starting or accelerating. On the other hand, in all-wheel drive mode, high driving force is not always necessary.

[0007] The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a control device for a hybrid vehicle that can suppress a decrease in drivability and improve energy efficiency.

[0008] The gist of the first invention is: (a) a control device for a hybrid vehicle comprising an engine, an electric motor, and a driving force distribution device for distributing driving force to main drive wheels and auxiliary drive wheels, the control device comprising: (b) an engine control unit for controlling an operating state of the engine based on predetermined engine operating conditions for starting or stopping the engine; and (c) a driving mode control unit for controlling driving of the hybrid vehicle so as to realize a driving mode selected by a driver or automatically selected; (d) the driving modes include a towing mode for driving by being towed by a towing vehicle, a main drive wheel driving mode for driving by distributing the driving force only to the main drive wheels, and an all-wheel drive mode for driving by distributing the driving force to both the main drive wheels and the auxiliary drive wheels; and (e) the engine operating conditions are predetermined so that an operating ratio of the engine, which is a ratio of an operating time of the engine to an operating time of the hybrid vehicle, is higher when the towing mode is selected than when the all-wheel drive mode is selected.

[0009] In addition, the second invention is a control device for the hybrid vehicle described in the first invention, wherein the engine operating condition is predetermined so that when the towing mode is selected and when the all-wheel drive mode is selected, the engine operating ratio is higher than when the main drive wheel drive mode is selected and the towing mode is not selected.

[0010] In addition, the third invention is a control device for the hybrid vehicle described in the second invention, wherein the engine operation condition includes an engine intermittent operation condition, which prohibits the engine intermittent operation of switching the engine between a running state and a stopped state when the towing mode is selected and when the all-wheel drive mode is selected, respectively, and on the other hand, permits the engine intermittent operation when the main drive wheel drive mode is selected and the towing mode is not selected.

[0011] In addition, the fourth invention is that in the control device of the hybrid vehicle described in the first invention, the engine operation condition includes an engine start condition, which is that when the towing mode is selected when the hybrid vehicle is in a predetermined state, the engine is started from the selection time point of the towing mode; on the other hand, when the all-wheel drive mode is selected when the hybrid vehicle is in the predetermined state, the engine is started from the time point when a predetermined request is made in the hybrid vehicle after the all-wheel drive mode is selected.

[0012] In addition, according to the fifth invention, in the control device of the hybrid vehicle described in the fourth invention, the predetermined state is a state in which the hybrid vehicle is stopped and the vehicle power transmission device for transmitting the driving force is set to a forward driving position capable of transmitting the forward driving force, or a state in which the output rotating component of the vehicle power transmission device is set to a neutral position in which the driving force cannot be transmitted because the output rotating component is not mechanically fixed in a non-rotatable manner, and the predetermined request is an acceleration request to increase the driving force, or a charging request for the storage device that exchanges electric power with the electric motor.

[0013] In addition, the sixth invention is a control device for a hybrid vehicle according to the fourth invention, wherein the all-wheel drive mode includes a low-speed all-wheel drive mode in which a transmission is set to the low gear and a high gear is selectively formed by the action of a bite clutch provided in the driving force distribution device, and the transmission is set to the low gear, and a high-speed all-wheel drive mode in which the transmission is set to the high gear, 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 gear, and the control device for the hybrid vehicle further includes a motor control unit that, when controlling in the high-speed main drive wheel drive mode when both the engine and the motor are set to a stopped state, causes a predetermined torque for generating a creep phenomenon to be output from the motor while maintaining the stopped state of the engine when switching from the high-speed main drive wheel drive mode to the high-speed all-wheel drive mode by selecting the high-speed all-wheel drive mode.

[0014] In addition, the gist of the seventh invention is that: (a) a control device for a hybrid vehicle having an engine and an electric motor, the control device for the hybrid vehicle including: (b) an engine control unit for controlling the operating state of the engine based on predetermined engine operating conditions for starting or stopping the engine; and (c) a driving mode control unit for controlling the driving of the hybrid vehicle in a manner that realizes a driving mode selected by a driver or automatically selected, (d) the driving mode includes a first towing mode for driving by being towed by a towing vehicle and a second towing mode different from the first towing mode for driving by being towed by the towed vehicle, and (e) the engine operating conditions are predetermined so that when the first towing mode is selected, the engine operating ratio, which is the ratio of the engine operating time to the operating time of the hybrid vehicle, is higher than when the second towing mode is selected.

[0015] Furthermore, an eighth invention provides the hybrid vehicle control device according to the seventh invention, wherein the second towing mode is a towing mode selected when the total weight of the towed vehicle is lighter than that of the first towing mode.

[0016] In addition, the 9th invention is that the control device of the hybrid vehicle described in the 7th invention further includes a driving control unit, which is capable of executing manual driving control for driving the hybrid vehicle according to the driving operation of the driver and driving assistance control for driving the hybrid vehicle by at least automatically accelerating and decelerating, the first towing mode is a towing mode selected when executing the manual driving control, and the second towing mode is a towing mode selected when executing the driving assistance control.

[0017] In addition, the 10th invention is the control device of the hybrid vehicle described in the 7th invention, wherein the driving mode includes an engine intermittent operation in which the engine is switched between a running state and a stopped state and a charge amount maintenance mode in which motor driving using only the electric motor as a driving force source is enabled in the stopped state of the engine, and a charge amount consumption mode in which the motor driving can be continued longer than in the charge amount maintenance mode, the first towing mode is a towing mode selected when the charge amount maintenance mode is executed, and the second towing mode is a towing mode selected when the charge amount consumption mode is executed.

[0018] In addition, the 11th invention is a control device for a hybrid vehicle described in the 7th invention, wherein the driving mode includes an engine braking mode in which an engine braking torque based on the rotational resistance of the engine is applied during deceleration driving, and a regenerative braking mode in which a regenerative braking torque based on the regeneration of the electric motor is applied preferentially over the engine braking torque during deceleration driving, the first towing mode is a towing mode selected when the engine braking mode is selected, and the second towing mode is a towing mode selected when the regenerative braking mode is selected.

[0019] In addition, the 12th invention is a control device for a hybrid vehicle described in the 7th invention, wherein the driving modes include an all-wheel drive mode in which the vehicle travels by distributing the driving force to both the main drive wheels and the auxiliary drive wheels through a driving force distribution device that distributes the driving force to the main drive wheels, and a main drive wheel drive mode in which the vehicle travels by distributing the driving force only to the main drive wheels, the first towing mode is a towing mode selected when the all-wheel drive mode is selected, and the second towing mode is a towing mode selected when the main drive wheel drive mode is selected.

[0020] In addition, the gist of the 13th invention is that: (a) a control device for a hybrid vehicle including an engine, an electric motor, and a driving force distribution device for distributing driving force to main drive wheels and auxiliary drive wheels, the control device for the hybrid vehicle comprising: (b) an engine control unit for controlling an operating state of the engine based on predetermined engine operating conditions for starting or stopping the engine; and (c) a driving mode control unit for controlling the driving of the hybrid vehicle so as to realize a driving mode selected by a driver or automatically selected, (d) the driving modes include a first all-wheel drive mode for driving by distributing the driving force to both the main drive wheels and the auxiliary drive wheels, and a second all-wheel drive mode different from the first all-wheel drive mode, for driving by distributing the driving force to both the main drive wheels and the auxiliary drive wheels, and (e) the engine operating conditions are predetermined so that an operating ratio of the engine, which is a ratio of an operating time of the engine to an operating time of the hybrid vehicle, is higher when the first all-wheel drive mode is selected than when the second all-wheel drive mode is selected.

[0021] In addition, the 14th invention is a control device for the hybrid vehicle described in the 13th invention, which further includes a driving control unit, which is capable of executing manual driving control for driving the hybrid vehicle according to the driving operation of the driver, and driving assistance control for driving the hybrid vehicle by at least automatically accelerating and decelerating, the first all-wheel drive mode is an all-wheel drive mode selected when the manual driving control is executed, and the second all-wheel drive mode is an all-wheel drive mode selected when the driving assistance control is executed.

[0022] In addition, the 15th invention is a control device for a hybrid vehicle described in the 13th invention, wherein the driving mode includes an engine intermittent operation in which the engine is switched between a running state and a stopped state and a charge amount maintenance mode in which motor driving using only the electric motor as a driving force source is enabled in the stopped state of the engine, and a charge amount consumption mode in which the motor driving can be continued longer than in the charge amount maintenance mode, the first all-wheel drive mode is an all-wheel drive mode selected when the charge amount maintenance mode is executed, and the second all-wheel drive mode is an all-wheel drive mode selected when the charge amount consumption mode is executed.

[0023] In addition, the 16th invention is a control device for a hybrid vehicle described in the 13th invention, wherein the driving mode includes an engine braking mode in which an engine braking torque based on the rotational resistance of the engine is applied during deceleration driving, and a regenerative braking mode in which a regenerative braking torque based on the regeneration of the electric motor is applied preferentially over the engine braking torque during deceleration driving, the first all-wheel drive mode is an all-wheel drive mode selected when the engine braking mode is selected, and the second all-wheel drive mode is an all-wheel drive mode selected when the regenerative braking mode is selected.

[0024] In addition, according to the 17th invention, in the control device of the hybrid vehicle described in the 13th invention, the driving mode includes a towing mode in which the vehicle is towed by a towing vehicle, the first all-wheel drive mode is an all-wheel drive mode selected when the towing mode is selected, and the second all-wheel drive mode is an all-wheel drive mode selected when the towing mode is not selected.

[0025] According to the first invention, the engine operating conditions for starting or stopping the engine are predetermined so that the engine's operating ratio is higher when towing mode is selected than when all-wheel drive mode is selected. This makes it easier to ensure sufficient driving force when towing mode is selected and improve energy efficiency when all-wheel drive mode is selected. Specifically, the engine is started or stopped depending on whether towing mode, which definitely requires high driving force during launch or acceleration, or all-wheel drive mode, which does not necessarily require high driving force. This allows for improved energy efficiency while minimizing degradation in drivability.

[0026] In addition, according to the second invention, the engine operating conditions are predetermined so that the engine operation ratio is higher when the towing mode is selected and when the all-wheel drive mode is selected than when the main drive wheel drive mode is selected and the towing mode is not selected, so it is easy to ensure the necessary driving force when the towing mode is selected and of course when the all-wheel drive mode is selected.

[0027] In addition, according to the third invention, the engine operation condition includes an engine intermittent operation condition, which prohibits engine intermittent operation when the towing mode is selected and when the all-wheel drive mode is selected. On the other hand, when the main drive wheel drive mode is selected and the towing mode is not selected, the engine intermittent operation is permitted, so it is easy to further ensure the necessary driving force when the towing mode is selected and of course when the all-wheel drive mode is selected.

[0028] In addition, according to the fourth invention, the engine operation conditions include an engine start condition, and the engine start condition is that when the towing mode is selected when the hybrid vehicle is in a predetermined state, the engine is started from the time point when the towing mode is selected. On the other hand, when the all-wheel drive mode is selected when the hybrid vehicle is in the predetermined state, the engine is started from the time point when a predetermined request is made in the hybrid vehicle after the all-wheel drive mode is selected. Therefore, when the towing mode is selected, it is easy to ensure sufficient driving force when moving forward or accelerating, and it is easy to improve energy efficiency when the all-wheel drive mode is selected.

[0029] Furthermore, according to the fifth invention, the predetermined state is a state in which the hybrid vehicle is stopped and the vehicle power transmission device is set to the forward driving position or the neutral position, and the predetermined request is an acceleration request or a request to charge the power storage device. Therefore, when the towing mode is selected, it is easy to ensure sufficient driving force when moving forward, and when the all-wheel drive mode is selected, it is easy to improve energy efficiency.

[0030] Furthermore, according to the sixth invention, during control in the high-range main drive wheel drive mode when both the engine and the electric motor are stopped, when the high-range all-wheel drive mode is selected and the high-range main drive wheel drive mode is switched from the high-range main drive wheel drive mode to the high-range all-wheel drive mode, a predetermined torque that causes a creeping phenomenon is output from the electric motor while the engine is kept stopped. Therefore, in the high-range all-wheel drive mode, the rotation required for operating the bite clutch provided in the transmission of the drive force distribution device is easily obtained by the rotation of the electric motor. Thus, even if the engine is stopped after switching to the high-range all-wheel drive mode, switching to the low-range all-wheel drive mode can be reliably performed.

[0031] Furthermore, according to the seventh invention, the engine operating conditions for starting or stopping the engine are predetermined so that the engine operation ratio is higher when the first towing mode is selected than when the second towing mode is selected. This makes it easier to ensure sufficient driving force when the first towing mode is selected, and easier to improve energy efficiency when the second towing mode is selected. In other words, even in the towing mode, which requires high driving force for starting or accelerating, the number of situations in which the engine is stopped can be increased. Consequently, it is possible to suppress a decrease in drivability and improve energy efficiency.

[0032] Furthermore, according to the eighth invention, the second towing mode is a towing mode selected when the total weight of the towed vehicle is lighter than that of the first towing mode. Therefore, even in the towing mode requiring a large driving force when moving forward or accelerating, in the second towing mode, which places less emphasis on power performance than in the first towing mode, it is possible to increase the number of situations in which the engine is stopped.

[0033] Furthermore, according to the ninth invention, the first towing mode is a towing mode selected when manual driving control is executed, and the second towing mode is a towing mode selected when driving support control is executed. Therefore, even in the towing mode that requires a large driving force when moving forward or accelerating, when the driving support control with a greater degree of freedom in the driving force requested than the manual driving control is executed, it is possible to increase the number of situations in which the engine is brought to a stopped state.

[0034] In addition, according to the tenth invention, the first towing mode is a towing mode selected when the charge maintaining mode is executed, and the second towing mode is a towing mode selected when the charge consumption mode that can continue motor driving longer than the charge maintaining mode is executed. Therefore, even in the towing mode that requires a large driving force when moving forward or accelerating, when the charge consumption mode that emphasizes energy efficiency rather than power performance is executed compared to the charge maintaining mode, it is possible to increase the number of situations in which the engine is stopped.

[0035] Furthermore, according to the eleventh invention, the first towing mode is a towing mode selected when the engine brake mode is selected, and the second towing mode is a towing mode selected when the regenerative braking mode is selected. Therefore, even in the towing mode which requires a large driving force when moving forward or accelerating, when the regenerative braking mode is selected, which prioritizes energy efficiency over the engine brake mode which requires maintaining the engine in a rotating state, it is possible to increase the number of situations in which the engine is brought to a stopped state.

[0036] Furthermore, according to the twelfth invention, the first towing mode is the towing mode selected when the all-wheel drive mode is selected, and the second towing mode is the towing mode selected when the main drive wheel drive mode is selected. Therefore, even in the towing mode which requires a large driving force when moving forward or accelerating, when the main drive wheel drive mode is selected which places less emphasis on power performance than when the all-wheel drive mode is selected, it is possible to increase the number of situations in which the engine is stopped.

[0037] Furthermore, according to the thirteenth invention, the engine operating conditions for starting or stopping the engine are predetermined so that the engine operation ratio is higher when the first all-wheel drive mode is selected than when the second all-wheel drive mode is selected. This makes it easier to ensure sufficient driving force when the first all-wheel drive mode is selected, and easier to improve energy efficiency when the second all-wheel drive mode is selected. In other words, even in an all-wheel drive mode requiring high driving force, the number of situations in which the engine can be stopped can be increased. Consequently, it is possible to suppress a decrease in drivability and improve energy efficiency.

[0038] Furthermore, according to the fourteenth invention, the first all-wheel drive mode is an all-wheel drive mode selected when manual driving control is executed, and the second all-wheel drive mode is an all-wheel drive mode selected when driving support control is executed. Therefore, even in the all-wheel drive mode requiring a large driving force, when the driving support control having a greater degree of freedom in the driving force requested compared to the manual driving control is executed, it is possible to increase the number of situations in which the engine is brought to a stopped state.

[0039] In addition, according to the 15th invention, the first all-wheel drive mode is an all-wheel drive mode selected when the charge amount maintenance mode is executed, and the second all-wheel drive mode is an all-wheel drive mode selected when the charge amount consumption mode that can continue motor driving is executed compared to the charge amount maintenance mode. Therefore, even in the all-wheel drive mode that requires a large driving force, when the charge amount consumption mode that emphasizes energy efficiency rather than power performance is executed compared to the charge amount maintenance mode, it is possible to increase the situation where the engine is stopped.

[0040] Furthermore, according to the sixteenth invention, the first all-wheel drive mode is an all-wheel drive mode selected when the engine brake mode is selected, and the second all-wheel drive mode is an all-wheel drive mode selected when the regenerative brake mode is selected. Even in the all-wheel drive mode requiring a large driving force, when the regenerative brake mode is selected, which prioritizes energy efficiency over the engine brake mode requiring the engine to be maintained in a rotating state, the situation in which the engine is brought to a stopped state can be increased.

[0041] Furthermore, according to the seventeenth invention, the first all-wheel drive mode is the all-wheel drive mode selected when the towing mode is selected, and the second all-wheel drive mode is the all-wheel drive mode selected when the towing mode is not selected. Therefore, even in the all-wheel drive mode requiring a large driving force, when the towing mode is not selected, which places less emphasis on power performance than when the towing mode is selected, it is possible to increase the number of situations in which the engine is stopped. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is a diagram illustrating control functions for various controls in the vehicle and main parts of the control system.

[0043] Figure 2 It is an explanation Figure 1 A diagram showing the key points of the transmission structure.

[0044] Figure 3 This is a flowchart illustrating a main portion of a control operation of the electronic control device, and is a flowchart illustrating a control operation for suppressing a decrease in drivability and improving energy efficiency.

[0045] Figure 4 This is a diagram illustrating a schematic structure of a vehicle to which the present invention is applied, and is a diagram illustrating control functions for various controls in the vehicle and a main portion of the control system, and is Figure 1 Different embodiments.

[0046] Figure 5 This is a flowchart illustrating the main part of the control operation of the electronic control device, and is a flowchart illustrating the control operation for suppressing the deterioration of drivability and improving energy efficiency, and is related to Figure 3 Flowcharts of different embodiments.

[0047] Figure 6 This is a flowchart illustrating the main part of the control operation of the electronic control device, and is a flowchart illustrating the control operation for suppressing the deterioration of drivability and improving energy efficiency, and is related to Figure 3 、 Figure 5 Flowcharts of different embodiments.

[0048] (Explanation of Symbols)

[0049] 10: Vehicle (hybrid electric 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: Transmission device (driving force distribution device); 48: Transmission output shaft (output rotating component); 54: Battery (power storage device); 90: Electronic control unit (control unit); 92a: Engine control unit; 92b: Electric motor control unit; 96: Driving mode control unit; 98: Driving control unit; 106: Auxiliary transmission (transmission); 120: Engaging clutch for auxiliary transmission (engaging clutch); 200: Vehicle (hybrid electric vehicle); MG: Electric motor. DETAILED DESCRIPTION

[0050] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0051] [Example 1]

[0052] Figure 1 1 is a diagram illustrating a schematic structure of a vehicle 10 to which the present invention is applied, and is a diagram illustrating control functions for various controls in the vehicle 10 and a main part of the control system. Figure 1 In the figure, vehicle 10 is a hybrid vehicle including an engine 12 and an electric motor MG as driving force sources for traveling. Vehicle 10 also 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. Power transmission device 18 is a vehicle power transmission device that transmits driving force from engine 12, etc., to front wheels 14 and rear wheels 16, respectively.

[0053] Vehicle 10 is an all-wheel drive vehicle based on a front-engine / rear-drive (FR) main-drive wheel-drive vehicle. Vehicle 10 is a four-wheel drive vehicle based on a FR two-wheel drive vehicle, with two wheels each for the front wheels 14 and rear wheels 16. In this embodiment, main-drive wheel drive and two-wheel drive (2WD) are synonymous, while all-wheel drive (AWD) and four-wheel drive (4WD) are synonymous. The rear wheels 16 are the main drive wheels, serving as drive wheels in both 2WD and AWD driving. The front wheels 14 are auxiliary drive wheels, serving as driven wheels in 2WD driving and as drive wheels in AWD driving. 2WD driving refers to driving in the 2WD mode, where the driving force from the engine 12, etc., is transmitted only to the rear wheels 16. AWD driving refers to driving in the AWD mode, where the driving force from the engine 12, etc., is transmitted to both the rear wheels 16 and the front wheels 14.

[0054] The engine 12 is a well-known internal combustion engine such as a gasoline engine or a diesel engine. Regarding the engine 12, an engine control unit 50 including a throttle actuator, a fuel injection device, an ignition device, etc. provided in the vehicle 10 is controlled by an electronic control unit 90 (described later), thereby controlling the engine torque Te, which is the output torque of the engine 12.

[0055] The electric motor MG is a rotating electrical machine that functions as an engine that generates mechanical power from electricity and as a generator that generates electricity from mechanical power, 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 exchanges electricity with the electric motor MG. The electric motor MG controls the inverter 52 by the electronic control unit 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, which is the same rotation direction as when the engine 12 is running, the MG torque Tm is a power running torque when it becomes a positive torque on the acceleration side, and a regenerative torque when it becomes a negative torque on the deceleration side. With respect to the above-mentioned electric power, electric energy has the same meaning unless otherwise specified. With respect to the above-mentioned power, torque and force have the same meaning unless otherwise specified.

[0056] The power transmission device 18 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, a transmission 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 housed within a housing 40, a non-rotating member attached to the vehicle body. Furthermore, within the housing 40, the power transmission device 18 includes an engine coupling shaft 42 that couples the engine 12 and the K0 clutch 20, and a motor coupling shaft 44 that couples the K0 clutch 20 and the torque converter 22.

[0057] The K0 clutch 20 is a clutch provided in the power transmission path between the engine 12 and the torque converter 22. Specifically, the torque converter 22 is coupled 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 transmission 26. Specifically, the torque converter 22 is coupled to a transmission input shaft 46, which serves as an input rotating member of the automatic transmission 24. The transmission 26 is coupled to a transmission output shaft 48, which serves as an output rotating member of the automatic transmission 24.

[0058] The electric motor MG is connected to the motor coupling shaft 44 within the housing 40 in a power-transmittable manner. Specifically, 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. From a different perspective, 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.

[0059] The torque converter 22 is a fluid transmission device that transmits 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 driving forces from the engine 12 and the motor MG to the transmission 26 .

[0060] The front differential 36 is equipped with an ADD (Automatic Disconnecting Differential) mechanism 37. The ADD mechanism 37 is, for example, a bite-type clutch that functions as a disconnecting clutch. The ADD mechanism 37 switches the front differential 36 to a locked state by setting its operating state, or control state, to an engaged state. Conversely, the ADD mechanism 37 switches its control state to a disengaged state, switching the front differential 36 to an unlocked state. The ADD mechanism 37 switches its control state by controlling an ADD mechanism actuator 56 provided in the vehicle 10, which is controlled by the electronic control unit 90 (described later).

[0061] The automatic transmission 24 is, for example, a well-known planetary gear type automatic transmission equipped with one or more planetary gear sets (not shown) and a plurality of engagement devices CB. The engagement devices CB are, for example, well-known hydraulic friction engagement devices. The engagement devices CB switch control states, such as the engaged and disengaged states, by varying the CB torque Tcb, representing each torque capacity, using a regulated CB hydraulic pressure PRcb supplied from a hydraulic control circuit 58 provided in the vehicle 10. The hydraulic control circuit 58 is controlled by an electronic control unit 90, described later.

[0062] The automatic transmission 24 is a stepped transmission that, by engaging any of the engagement devices CB, establishes any of a plurality of speed steps (also referred to as gears) with different speed ratios (also referred to as gear ratios) γat (=AT input speed Ni / AT output speed No). The automatic transmission 24 switches gears based on the driver's (=driver's) accelerator operation, vehicle speed V, and other factors, via the electronic control unit 90 (described later). The AT input speed Ni is the speed of the transmission input shaft 46 and is the input speed of the automatic transmission 24. The AT output speed No is the speed of the transmission output shaft 48 and is the output speed of the automatic transmission 24.

[0063] The K0 clutch 20 is a wet or dry friction engagement device, for example, comprised of a multi-plate or single-plate clutch pressed by a hydraulic actuator. The K0 clutch 20 switches between controlled states, such as engaged and disengaged, by varying the K0 torque Tk0, representing the torque capacity of the K0 clutch 20, using the regulated K0 hydraulic pressure PRk0 supplied from the hydraulic control circuit 58.

[0064] The transmission 26 selectively switches between connecting and disconnecting the power transmission between, for example, the rear propeller shaft 28 and the front propeller shaft 34. Thus, the transmission 26 transmits the driving force transmitted from the automatic transmission 24 only to the rear wheels 16, or distributes it to both the front wheels 14 and the rear wheels 16. Thus, the transmission 26 is a driving force distribution device that distributes the driving force between the main drive wheels and the auxiliary drive wheels.

[0065] Figure 2 2 is a diagram illustrating the structure of the transmission device 26. Figure 2 1 is a development view showing the respective 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 transmission 26 includes a transmission case 100, which serves as a non-rotating member, connected to the vehicle rear side of the housing 40. The transmission 26 includes an input shaft 102, a first output shaft 104, an auxiliary transmission 106, a power distribution clutch 108, and a drive gear 110, all disposed on a common first axis CS1 within the transmission case 100. Furthermore, the transmission 26 includes a second output shaft 112 and a driven gear 114, all disposed on a common second axis CS2 within the transmission case 100. The transmission 26 also includes a chain 116 connecting the drive gear 110 and the driven gear 114.

[0066] The input shaft 102 is connected to the transmission output shaft 48. The first output shaft 104 is connected to the rear propeller shaft 28. The second output shaft 112 is connected to the front propeller shaft 34. The drive gear 110 is configured to selectively switch between allowing and preventing relative rotation of the first output shaft 104. The driven gear 114 is configured to prevent relative rotation of the second output shaft 112.

[0067] The auxiliary transmission 106 includes a planetary gear unit 118 and an auxiliary transmission clutch 120. The auxiliary transmission clutch 120 includes a high-side meshing mechanism 122 for establishing a high gear position (GSH), which is a gear position with a smaller speed ratio, and a low-side meshing mechanism 124 for establishing a low gear position (GSL), which is a gear position with a larger speed ratio. The high-side meshing mechanism 122 and the low-side meshing mechanism 124 are each, for example, meshing clutches with synchronized meshing mechanisms. In other words, the auxiliary transmission 106 is a transmission that selectively establishes a low gear position (GSL) or a high gear position (GSH) through the operation of the auxiliary transmission clutch 120, which is a meshing clutch. The transmission 26 transmits the rotation of the input shaft 102 to the first output shaft 104 via the auxiliary transmission 106.

[0068] The power distribution clutch 108 is an engagement device that selectively switches between allowing and preventing relative rotation of the drive gear 110 with respect to the first output shaft 104. The power distribution clutch 108 is, for example, a clutch with a synchronized meshing mechanism. When the power distribution clutch 108 is disengaged, the drive gear 110 can rotate relative to the first output shaft 104 about the first axis CS1. This prevents power transmission between the first output shaft 104 and the second output shaft 112 via the drive gear 110 and other components. On the other hand, when the power distribution clutch 108 is engaged, the drive gear 110 is prevented from rotating relative to the first output shaft 104 about the first axis CS1. This allows power transmission 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 and other components.

[0069] The transmission 26 further includes a shift actuator 126 fixed to the transmission case 100. The shift actuator 126 is an actuator for operating the auxiliary transmission bite clutch 120 and the power distribution bite clutch 108, respectively.

[0070] Return to Figure 1 When the power distribution clutch 108 is engaged in the transmission 26 and the ADD mechanism 37 is engaged in the front differential 36, the driving force distributed to the second output shaft 112 by the transmission 26 is transmitted to the front differential 36 via the front propeller shaft 34 and then to the front wheels 14 via the front drive shaft 38. Furthermore, the remaining driving force not distributed to the second output shaft 112 by the transmission 26 is transmitted to the rear differential 30 via the rear propeller shaft 28 and then to the rear wheels 16 via the rear drive shaft 32. As a result, the vehicle 10 enters the AWD mode.

[0071] On the other hand, when the power distribution clutch 108 is disengaged in the transmission 26, the driving force is transmitted only to the rear wheels 16 via the transmission 26, so that the vehicle 10 is in the 2WD state. In the vehicle 10, for example, the ADD mechanism 37 is disengaged in conjunction with the 2WD state.

[0072] 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 disengaged, power transmission between the engine 12 and the torque converter 22 is cut off. Since the electric motor MG is connected to the torque converter 22, the K0 clutch 20 functions as a clutch that disconnects the engine 12 from the electric motor MG.

[0073] In the power transmission device 18, the driving force output from the engine 12 is transmitted from the engine connecting shaft 42 to the transmission 26 in this order, passing through the K0 clutch 20, the motor connecting shaft 44, the torque converter 22, the automatic transmission 24, and the like, when the K0 clutch 20 is engaged. Furthermore, the driving force output from the electric motor MG is transmitted from the motor connecting shaft 44 to the transmission 26 in this order, passing through the torque converter 22, the automatic transmission 24, and the like, regardless of the control state of the K0 clutch 20. Furthermore, in the 2WD state, the driving force transmitted to the transmission 26 is transmitted from the transmission 26 to the rear wheels 16. Alternatively, in the AWD state, the driving force transmitted to the transmission 26 is distributed by the transmission 26 to the rear wheels 16 and the front wheels 14.

[0074] The vehicle 10 includes a mechanical oil pump (MOP60), an electric oil pump (EOP62), a pump motor 64, and the like. The MOP60 is connected to the motor connecting shaft 44 and is rotationally driven by the driving force source (engine 12, electric motor MG) to discharge hydraulic oil (OIL) for use in the power transmission device 18. The pump motor 64 is a motor dedicated to the EOP62 for rotationally driving the EOP62. The EOP62 is rotationally driven by the pump motor 64 to discharge hydraulic oil (OIL). The hydraulic oil (OIL) discharged from the MOP60 and EOP62 is supplied to the hydraulic control circuit 58. The hydraulic control circuit 58 supplies, for example, CB hydraulic pressure PRcb and K0 hydraulic pressure PRk0, whose pressures are adjusted according to the hydraulic oil (OIL) discharged from the MOP60 and / or EOP62.

[0075] The vehicle 10 is equipped with a wheel brake device 66. The wheel brake device 66 applies a braking torque TB generated by the wheel brakes to each of the front wheels 14 and the rear wheels 16. The wheel brake device 66 supplies brake fluid pressure to the wheel cylinders provided in the wheel brakes in response to, for example, a driver's application of a brake pedal. In normal operation, the wheel brake device 66 supplies a master cylinder fluid pressure corresponding to the braking operation amount Bra generated by the master cylinder as brake fluid pressure to the wheel cylinders. On the other hand, when the ABS function is activated, the brake assist function is activated, the TRC function is activated, the side slip control (VSC) is activated, the vehicle speed is controlled, or the automatic braking function is activated, the wheel brake device 66 supplies a brake fluid pressure corresponding to the braking torque TB required for each control to generate the braking torque TB through the wheel brakes. The braking operation amount Bra is a signal indicating the magnitude of the driver's brake pedal application, i.e., the magnitude of the braking operation, corresponding to the brake pedal force.

[0076] The vehicle 10 further includes an electronic control unit 90, which includes control devices for the vehicle 10 related to, for example, control of the engine 12. The electronic control unit 90 is configured as a so-called microcomputer including a CPU, RAM, ROM, and input / output interfaces. The CPU utilizes the RAM's temporary storage function and processes signals according to programs pre-stored in the ROM to execute various controls for the vehicle 10. The electronic control unit 90 may include various computers for engine control, motor control, hydraulic control, and the like, as needed.

[0077] Various signals based on detection values ​​detected by various sensors installed in the vehicle 10 (e.g., the engine speed sensor 70, the input speed sensor 71, the output speed sensor 72, the MG speed sensor 73, the wheel speed sensor 74, the accelerator opening sensor 75, the throttle opening sensor 76, the brake pedal sensor 77, the G sensor 78, the yaw rate sensor 79, the shift position sensor 80, the towing selection switch 81, the drive switching dial switch 82, the battery sensor 83, the oil temperature sensor 84, etc.) are supplied to the electronic control unit 90 (e.g., the engine speed Ne as the speed of the engine 12, the AT input speed Ni, the AT output speed No corresponding to the vehicle speed V, the MG speed Nm as the speed of the electric motor MG, the wheel speed Nr as the speed of each of the front wheels 14 and the rear wheels 16, the driving speed indicating the magnitude of the driver's accelerator operation). The information includes an acceleration opening θacc which is an acceleration operation amount of the driver, a throttle opening θth which is an opening of the electronic throttle, a brake-on signal Bon which is a signal indicating a state of a brake pedal operated by the driver to actuate the wheel brakes, a brake operation amount Bra, a longitudinal acceleration Gx and a lateral acceleration Gy of the vehicle 10, a yaw rate Ryaw which is an angular velocity of rotation about a vertical axis of the vehicle 10, a shift operation position POSsh which indicates an operation position of a shift lever 68 provided on the vehicle 10, a tow mode on signal TOWon which is a signal indicating that the driver has selected the tow mode, a dial operation position POSdl which is a signal indicating an operation position of the drive switching dial switch 82, a battery temperature THbat of the battery 54, a battery charge and discharge current Ibat, a battery voltage Vbat, a working oil temperature THoil which is a temperature of the working oil OIL, etc.

[0078] The shift lever 68 is a shift operating member that is 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 68 for selecting a shift position of the power transmission device 18, particularly the automatic transmission 24, and includes, for example, the P, R, N, and D operating positions.

[0079] The P operating position is a parking operating position in which the parking position (=P position) of the automatic transmission 24 is selected. The P position of the automatic transmission 24 is a shift position in which the automatic transmission 24 is in 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 driving force. This state is achieved, for example, by disengaging both engagement devices CB, thereby cutting off power transmission within the automatic transmission 24. The state in which the rotation of the transmission output shaft 48 is mechanically blocked refers to a parking lock state in which the transmission output shaft 48 is fixed in a non-rotatable manner by a known parking lock mechanism provided on the vehicle 10. The R operating position is a reverse travel operating position in which the reverse travel position (=R position) of the automatic transmission 24 is selected. The R position of the automatic transmission 24 is a shift position in which the automatic transmission 24 enables the vehicle 10 to travel in reverse. The N operating range is a neutral operating range in which the neutral range (=N range) serving as the neutral position of the automatic transmission 24 is selected. The N range of the automatic transmission 24 is a shift range in which the automatic transmission 24 is set to the neutral state. In other words, the N range of the automatic transmission 24 is a shift range in which the transmission output shaft 48 is not mechanically fixed in a non-rotatable manner and cannot transmit driving force. The D operating range is a forward travel operating range in which the forward travel range (=D range) serving as the forward travel position of the automatic transmission 24 is selected. The D range of the automatic transmission 24 is a shift range in which the automatic transmission 24 executes automatic speed control to enable the vehicle 10 to travel forward. In other words, the D range of the automatic transmission 24 is a shift range in which the automatic transmission 24 can transmit driving force for forward travel.

[0080] The towing select switch 81 is, for example, a push-button switch located near the driver's seat and operated by the driver when the vehicle is towed by the tractor. When the driver operates the towing select switch 81, the towing mode is selected as the driving mode. The towing mode is a driving mode in which the vehicle is towed by the tractor. The towing select switch 81 is not limited to the push-button type described above; it may also be a slide-type, seesaw-type, or other type.

[0081] The drive switching dial switch 82 is, for example, a dial-type switch located near the driver's seat and operated by the driver to select the driving state of the vehicle 10. The drive switching dial switch 82 has three operating positions: "H-2WD," "H-AWD," and "L-AWD." When the drive switching dial switch 82 is in the "H-2WD" position, the high-speed 2WD mode is selected as the driving mode. When the drive switching dial switch 82 is in the "H-AWD" position, the high-speed AWD mode is selected as the driving mode. When the drive switching dial switch 82 is in the "L-AWD" position, the low-speed AWD mode is selected as the driving mode. The high-speed 2WD mode is a driving mode in which the vehicle 10 is in the 2WD state with the auxiliary transmission 106 in the transmission 26 set to the high gear position GSH. In the 2WD mode, which is a driving mode in which the driving force is distributed only to the rear wheels 16, the auxiliary transmission 106 is basically set to the high gear position GSH. That is, in this embodiment, the 2WD mode is a high-range 2WD mode. The high-range AWD mode is a driving mode in which the vehicle 10 is driven in an AWD state with the auxiliary transmission 106 set to the high gear position GSH. The low-range AWD mode is a driving mode in which the vehicle 10 is driven in an AWD state with the auxiliary transmission 106 set to the low gear position GSL. In this embodiment, the AWD modes, which are driving modes in which the driving force is distributed to both the rear wheels 16 and the front wheels 14, include a low-range AWD mode and a high-range AWD mode. Furthermore, the drive switching dial switch 82 is not limited to the aforementioned dial type, and may also be, for example, a sliding type, a seesaw type, or the like.

[0082] 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 EOP 62, a brake control command signal Sbra for controlling the braking torque TB based on the wheel brakes, a high-low switching control command signal Sh1 for switching the gear position of the auxiliary transmission 106 between a high gear position GSH and a low gear position GSL, a drive state switching control command signal Swd for controlling switching between a 2WD state and an AWD state through the transmission 26, etc.) are output from the electronic control unit 90 to each device provided in the vehicle 10 (e.g., an engine control unit 50, an inverter 52, an actuator 56 for the ADD mechanism, a hydraulic control circuit 58, a pump motor 64, a wheel brake device 66, a shift actuator 126, etc.).

[0083] To implement various controls in the vehicle 10 , the electronic control unit 90 includes a hybrid control unit 92 serving as a hybrid control means, a hydraulic control unit 94 serving as a hydraulic control means, and a driving mode control unit 96 serving as a driving mode control means.

[0084] The hybrid control unit 92 includes the functions of an engine control unit 92a, which serves as an engine control unit for controlling the operation of the engine 12, and a motor control unit 92b, which serves as a motor control unit for controlling the operation of the motor MG via the inverter 52. Through these control functions, hybrid drive control based on the engine 12 and the motor MG is performed.

[0085] The hybrid control unit 92 calculates the drive request amount for the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to the drive request amount map. The drive request amount map is a relationship that is determined and stored in advance through experiments or design. The drive request amount is, for example, the requested drive torque Trdem at the drive wheels (the rear wheels 16 and the front wheels 14). From a different perspective, the requested drive torque Trdem [Nm] is the requested drive power Prdem [W] at the current vehicle speed V. As the drive request amount, the requested drive force Frdem [N] at the drive wheels, the requested AT output torque at the transmission output shaft 48, etc. can also be used. In the calculation of the drive request amount, the AT output speed No, etc. can also be used instead of the vehicle speed V.

[0086] 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 electric motor MG, taking into account transmission losses, auxiliary loads, the gear ratio γat of the automatic transmission 24, the chargeable power Win and dischargeable power Wout of the battery 54, and other factors to achieve the requested drive power Prdem. The engine control command signal Se is, for example, a command value for engine power Pe, which is the power of the engine 12 that is output at the current engine speed Ne, resulting in an engine torque Te. The MG control command signal Sm is, for example, a command value for power consumption Wm of the electric motor MG, which is output at the current MG speed Nm, resulting in an MG torque Tm.

[0087] The chargeable power Win of the battery 54 is the maximum power that can be input, which limits 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 output, which limits the output power of the battery 54 and indicates the output limit of the battery 54. For example, the electronic control unit 90 calculates the chargeable power Win and the dischargeable power Wout of the battery 54 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 based on, for example, the battery charge and discharge current Ibat and the battery voltage Vbat.

[0088] When the requested drive torque Trdem can be supplied solely by the output of the electric motor MG, the hybrid control unit 92 switches the driving mode to the motor driving (EV driving) mode. In the EV driving mode, the hybrid control unit 92 performs EV driving, using only the electric motor MG as the driving force source with the K0 clutch 20 disengaged. On the other hand, when the requested drive torque Trdem cannot be supplied without at least the output of the engine 12, the hybrid control unit 92 switches the driving mode to the engine driving mode, or hybrid driving (HV driving) mode. In the HV driving mode, the hybrid control unit 92 performs engine driving, or HV driving, using at least the engine 12 as the driving force source with the K0 clutch 20 engaged. Even when the requested drive torque Trdem can be supplied solely by the output of the electric motor MG, the hybrid control unit 92 establishes the HV driving mode if, for example, the state of charge (SOC) of the battery 54 is less than a predetermined engine start threshold value (SOCengf) or if the engine 12 and other components need to be warmed up. The engine start threshold SOCengf is a predetermined threshold value of the state of charge (SOC) for determining whether the engine 12 needs to be forcibly started to charge the battery 54. Thus, the hybrid control unit 92 switches between the EV and HV driving modes by automatically stopping the engine 12 during HV driving, restarting the engine 12 after stopping it, or starting the engine 12 during EV driving, based on the requested drive torque Trdem and the like.

[0089] The engine control unit 92a determines whether there is a request to start the engine 12. For example, 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 greater than the range that can be supplied by the output of the electric motor MG alone, whether the engine 12 and the like need to be warmed up, or whether the state of charge value SOC of the battery 54 is less than the engine start threshold value SOCengf.

[0090] 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 pressure control command signal Sk0 to the hydraulic control circuit 58 for controlling the K0 clutch 20, which is in the disengaged state, to be engaged, so that K0 torque Tk0, which is torque required for starting the engine 12 and is used to increase the engine speed Ne, can be transmitted to the engine 12. In this embodiment, the torque required for starting the engine 12 is referred to as the required starting torque Tcrn.

[0091] 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 conjunction with the hydraulic control unit 94 switching the K0 clutch 20 to the engaged state.

[0092] When determining that there is a request to start the engine 12 , the engine control unit 92 a outputs an engine control command signal Se for starting fuel supply, engine ignition, etc. to the engine control device 50 in conjunction with starting the engine 12 by the K0 clutch 20 and the motor MG.

[0093] When starting the engine 12 during EV driving, the motor control unit 92b causes the motor MG to output the required cranking torque Tcrn, in addition to the MG torque Tm for EV driving, which generates the driving torque Tr. Therefore, during EV driving, it is necessary to pre-secure the required cranking torque Tcrn in preparation for starting the engine 12. Therefore, the range within which the requested driving torque Trdem can be supplied solely by the output of the motor MG is defined as the maximum output torque of the motor MG minus the required cranking torque Tcrn. The maximum output torque of the motor MG is the maximum MG torque Tm that can be output using the dischargeable power Wout of the battery 54.

[0094] The engine control unit 92a determines whether there is a request to stop the engine 12. For example, in the HV running mode, the engine control unit 92a determines whether there is a request to stop the engine 12 based on factors such as whether the requested drive torque Trdem is within the range that can be supplied solely by the output of the electric motor MG, whether preheating of the engine 12 and the like is unnecessary, and whether the state of charge value SOC of the battery 54 is greater than or equal to an engine start threshold value SOCengf.

[0095] When the engine control unit 92a determines that there is a request to stop the engine 12, it outputs an engine control command signal Se for stopping the supply of fuel to the engine 12 to the engine control device 50. In other words, when the engine 12 is stopped, the engine control unit 92a outputs the engine control command signal Se for controlling the engine 12 to the engine control device 50 so that the engine 12 stops operating.

[0096] When the engine control unit 92 a determines that there is a stop request for the engine 12 , the hydraulic control unit 94 outputs a K0 hydraulic control command signal Sk0 for controlling the engaged K0 clutch 20 to the disengaged state to the hydraulic control circuit 58 .

[0097] In this manner, the engine control unit 92a controls the operating state of the engine 12 based on predetermined engine operating conditions REQeng for starting or stopping the engine 12. The engine operating conditions REQeng include, for example, a predetermined driving power Prf that can be supplied solely by the output of the electric motor MG with respect to the required driving power Prdem, an engine starting threshold value SOCengf that requires charging of the battery 54 with respect to the state of charge value SOC of the battery 54, and the like.

[0098] The hydraulic control unit 94 uses, for example, a shift map representing a predetermined relationship to determine whether to shift the automatic transmission 24. The hydraulic control unit 94 outputs a CB hydraulic pressure control command signal Scb, which is used to execute shift control of the automatic transmission 24, to the hydraulic control circuit 58 as needed. The shift map, for example, includes predetermined relationships on a two-dimensional coordinate system with vehicle speed V and requested drive torque Trdem as variables, indicating shift lines for determining whether to shift the automatic transmission 24. The shift map may use, for example, the AT output speed No in place of vehicle speed V, or, alternatively, the requested drive force Frdem, accelerator opening θacc, throttle opening θth, and the like in place of requested drive torque Trdem.

[0099] 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 modes include a towing mode, a 2WD mode (i.e., a high-range 2WD mode), and an AWD mode including a low-range AWD mode and a high-range AWD mode selected by the driver.

[0100] The driving mode control unit 96 will use a predetermined shift map in which, for example, the gear of the automatic transmission 24 is more likely to become a low-side gear when the towing mode is selected through the towing selection switch 81, compared to the case where the towing mode is not selected, to execute the shift control instruction of the automatic transmission 24 and output it to the hydraulic control unit 94.

[0101] When the high-gear 2WD mode is selected by the drive switching dial switch 82, the driving mode control unit 96 outputs the high-low switching control instruction signal Shl for changing the gear position of the auxiliary transmission 106 to the high gear position GSH, and the driving state switching control instruction signal Swd for changing the power distribution engagement clutch 108 to the disengaged state to the shift actuator 126, and outputs the ADD switching control instruction signal Sadd for changing the ADD mechanism 37 to the disengaged state to the ADD mechanism actuator 56.

[0102] When the high-gear AWD mode is selected by the drive switching dial switch 82, the driving mode control unit 96 outputs the high-low switching control instruction signal Shl for changing the gear position of the auxiliary transmission 106 to the high gear position GSH, and the driving state switching control instruction signal Swd for changing the power distribution engagement clutch 108 to the engaged state to the shift actuator 126, and outputs the ADD switching control instruction signal Sadd for changing the ADD mechanism 37 to the engaged state to the ADD mechanism actuator 56.

[0103] When the low-speed AWD mode is selected by the drive switching dial switch 82, the driving mode control unit 96 outputs the high-low switching control instruction signal Shl for setting the gear position of the auxiliary transmission 106 to the low gear position GSL, and the driving state switching control instruction signal Swd for setting the power distribution clutch 108 to the engaged state to the shift actuator 126, and outputs the ADD switching control instruction signal Sadd for setting the ADD mechanism 37 to the engaged state to the ADD mechanism actuator 56.

[0104] Here, when towing mode and AWD mode are selected, a greater driving force Fr is likely to be required compared to normal mode. Normal mode is when towing mode is not selected and 2WD mode is selected. Since engine 12 is running in HV driving mode, a greater driving force Fr is likely to be obtained compared to EV driving mode. Therefore, the engine operation condition REQeng is predetermined so that the engine 12 operation ratio Reng is higher when towing mode and AWD mode are selected compared to normal mode. The engine 12 operation ratio Reng is the ratio of the engine 12 operation time to the vehicle 10 operating time. The vehicle 10 operating time is the time during which the main power supply of vehicle 10 is turned on, and is the sum of the engine 12 operation time and the engine 12 stop time. The engine 12 operation time is the time during which the engine 12 is in operation during the vehicle 10 operating time. The engine 12 stop time is the time during which the engine 12 is stopped during the vehicle 10 operating time.

[0105] The engine operating condition REQeng is predetermined so that, when the towing mode is selected and when the AWD mode is selected, for example, the predetermined driving power Prf is smaller or the engine start threshold value SOCengf is higher than that in the normal mode.

[0106] In normal mode, the EV driving mode and HV driving mode are switched by performing intermittent engine operation, which switches the engine 12 between an operating state and a stopped state. Considering responsiveness when a high driving force Fr is required, it is preferable to prohibit intermittent engine operation once the engine 12 is in the operating state, thereby preventing the engine 12 from being stopped. Therefore, the engine operation conditions REQeng include engine intermittent operation conditions that prohibit engine intermittent operation when towing mode and AWD mode are selected. Furthermore, the engine operation conditions REQeng include engine intermittent operation conditions that permit engine intermittent operation in normal mode.

[0107] However, in towing mode, a high driving force Fr is definitely required during launch or acceleration. On the other hand, in AWD mode, a high driving force Fr may not always be required. Energy efficiency can be improved by operating the engine 12 as needed. Therefore, the engine operating condition REQeng is predetermined so that the engine 12 operating ratio Reng is higher when towing mode is selected than when AWD mode is selected. In other words, the engine operating condition REQeng is predetermined so that the engine 12 is more likely to be stopped when AWD mode is selected than when towing mode is selected.

[0108] In tow mode, it is preferable to reliably secure the required driving force Fr by starting the engine 12 earlier than in AWD mode. Therefore, the engine operating condition REQeng includes an engine start condition for starting the engine 12 from the time tow mode is selected, for example, when tow mode is selected while the vehicle 10 is in the predetermined state STvf. Specifically, when tow mode is selected while the vehicle 10 is in the predetermined state STvf, the predetermined driving power Prf and the engine start threshold SOCengf are discarded, and the HV travel mode is assumed regardless of the requested driving power Prdem and the state of charge (SOC) of the battery 54. Furthermore, the engine operating condition REQeng includes an engine start condition for starting the engine 12 from the time the predetermined request REQvf is made in the vehicle 10 after AWD mode is selected, for example, when the vehicle 10 is in the predetermined state STvf.

[0109] In towing mode, a high driving force Fr is definitely required for moving forward. Therefore, the predetermined state STvf is, for example, a state in which the vehicle 10 is stopped and the shift position of the automatic transmission 24 is set to the D range or the N range. When the AWD mode is selected, the engine 12 is not started until the predetermined request REQvf is issued. Therefore, the predetermined state STvf when the AWD mode is selected may be a state in which the shift position of the automatic transmission 24 is set to the R range or the P range, in addition to the D range or the N range.

[0110] The predetermined request REQvf is an acceleration request to increase the driving force Fr or a request to charge the battery 54. The acceleration request to increase the driving force Fr is, for example, an increase in the requested driving force Frdem associated with an accelerator ON operation. The request to charge the battery 54 is, for example, a request to reduce the state of charge (SOC) of the battery 54 to below the engine start threshold value SOCengf. Alternatively, if the predetermined state STvf for selecting the AWD mode includes the P range or the N range, the predetermined request REQvf may include operating the shift lever 68 from the P or N range to the D or R range.

[0111] When switching between the low-range AWD mode and the high-range AWD mode, the sub-transmission clutch 120 needs to be switched in the sub-transmission 106. When switching the sub-transmission clutch 120, a certain degree of rotation is required in the input shaft 102, etc. When switching between the low-range AWD mode and the high-range AWD mode, the engine 12 needs to be put into operation or the electric motor MG needs to be rotated. When the AWD mode is selected, the engine 12 is not started until the predetermined request REQvf is made. Therefore, if the engine 12 is stopped when the AWD mode is selected, it is set to a state in which the electric motor MG is rotating. For example, when switching from the high-range 2WD mode to the high-range AWD mode, the sub-transmission clutch 120 is not switched, but in response to the switch from the high-range AWD mode to the low-range AWD mode, the electric motor MG is set to a state in which it is rotating.

[0112] When the motor control unit 92b is in the High 2WD mode with both the engine 12 and the electric motor MG stopped, and when the High 2WD mode is switched to the High AWD mode by selecting the High AWD mode, the motor control unit 92b executes, for example, MG idle control, which is idling control of the electric motor MG, while the engine 12 remains stopped. The MG idle control, for example, maintains the MG rotational speed Nm at a predetermined MG idle speed, thereby idling the electric motor MG. For example, when the accelerator is turned off while the engine 12 is stopped, the brake is turned off during a temporary stop, thereby outputting a predetermined torque from the electric motor MG to generate a creeping phenomenon, causing the vehicle 10 to move slowly while the accelerator is kept off. For example, the predetermined torque is a creeping torque used to cause the vehicle 10 to move through so-called creeping travel when the brake is turned off while the vehicle is stopped and the accelerator is kept off.

[0113] Figure 3 This is a flowchart explaining a main part of the control operation of the electronic control device 90 and is a flowchart explaining a control operation for suppressing a decrease in drivability and improving energy efficiency, and is executed repeatedly, for example.

[0114] exist Figure 3 First, in step S10 (omitted below), corresponding to the function of the driving mode control unit 96, a determination is made as to whether the towing mode is selected. If the determination in step S10 is affirmative, in step S20, corresponding to the function of the engine control unit 92a, the operating state of the engine 12 is controlled based on the engine operating condition REQeng when the towing mode is selected. If the determination in step S10 is negative, in step S30, corresponding to the function of the driving mode control unit 96, a determination is made as to whether the AWD mode is selected. If the determination in step S30 is positive, in step S40, corresponding to the function of the engine control unit 92a and the motor control unit 92b, the operating state of the engine 12 is controlled based on the engine operating condition REQeng when the AWD mode is selected. Furthermore, if the engine 12 is stopped during parking, creep torque is output from the electric motor MG. If the determination in step S30 is negative, in step S50, corresponding to the function of the engine control unit 92a, the operating state of the engine 12 is controlled based on the engine operating condition REQeng when the normal mode is selected.

[0115] As described above, according to this embodiment, the engine operating condition REQeng is predetermined so that the engine 12 operation ratio Reng is higher when the towing mode is selected than when the AWD mode is selected. This facilitates ensuring sufficient driving force Fr when the towing mode is selected, while facilitating improved energy efficiency when the AWD mode is selected. Specifically, the engine 12 is started or stopped depending on whether the towing mode, which definitely requires a high driving force Fr during launch or acceleration, or the AWD mode, which does not necessarily require a high driving force Fr. This allows for improved energy efficiency while minimizing degradation in drivability.

[0116] In addition, according to this embodiment, the engine operation condition REQeng is predetermined so that the operation ratio Reng of the engine 12 is higher when the towing mode is selected and when the AWD mode is selected than when the normal mode is selected, so it is easy to ensure the necessary driving force Fr when the towing mode is selected and of course when the AWD mode is selected.

[0117] In addition, according to the present embodiment, the engine operation condition REQeng includes an engine intermittent operation condition, which prohibits engine intermittent operation when the towing mode is selected and when the AWD mode is selected, respectively. On the other hand, engine intermittent operation is permitted in the normal mode, so it is easier to ensure the necessary driving force Fr when the towing mode is selected and of course when the AWD mode is selected.

[0118] In addition, according to the present embodiment, the engine operation condition REQeng includes an engine start condition. The engine start condition is that when the towing mode is selected when the vehicle 10 is in the predetermined state STvf, the engine 12 is started from the time when the towing mode is selected. On the other hand, when the AWD mode is selected when the vehicle 10 is in the predetermined state STvf, the engine 12 is started from the time when the predetermined request REQvf is made in the vehicle 10 after the AWD mode is selected. Therefore, when the towing mode is selected, it is easy to ensure sufficient driving force Fr when moving forward or accelerating, and when the AWD mode is selected, it is easy to improve energy efficiency.

[0119] In addition, according to this embodiment, the predetermined state STvf is a state in which the vehicle 10 is stopped and the shift position of the automatic transmission 24 is set to the D position or the N position, and the predetermined request REQvf is an acceleration request or a charging request for the battery 54. Therefore, when the towing mode is selected, it is easy to ensure sufficient driving force Fr when moving forward, and when the AWD mode is selected, it is easy to improve energy efficiency.

[0120] Furthermore, according to this embodiment, during control in the High 2WD mode when both the engine 12 and the electric motor MG are stopped, when the High 2WD mode is switched to the High AWD mode by selecting the High AWD mode, creep torque is output from the electric motor MG while the engine 12 is kept stopped. Therefore, in the High AWD mode, the rotation of the electric motor MG facilitates the rotation required for operating the auxiliary transmission clutch 120 in the auxiliary transmission 106. Consequently, even if the engine 12 is stopped after switching to the High AWD mode, the vehicle can reliably switch to the Low AWD mode.

[0121] Next, other embodiments of the present invention will be described. In the following description, the same reference numerals are given to the common parts of the embodiments, and description thereof will be omitted.

[0122] [Example 2]

[0123] Figure 4 1 and 2 are diagrams illustrating a schematic configuration of a vehicle 200 to which the present invention is applied, and are diagrams illustrating control functions for various controls in the vehicle 200 and a main portion of a control system. Figure 4 is with Figure 1 Different embodiments. Figure 4 In the embodiment, vehicle 200 is a hybrid vehicle similar to vehicle 10 in the first embodiment. Vehicle 200 differs from vehicle 10 primarily in that it includes a steering system 69, a steering sensor 85, a vehicle periphery information sensor 86, a vehicle position sensor 87, a navigation system 88, and various setting switches 89, and that the electronic control unit 90 includes a driving control unit 98. The differences from vehicle 10 will be primarily described.

[0124] The electronic control unit 90 is supplied with various signals based on detection values ​​detected by various sensors installed in the vehicle 200 (for example, a steering sensor 85, a vehicle peripheral information sensor 86, a vehicle position sensor 87, a navigation system 88, various setting switch groups 89, etc.) (for example, a steering angle θsw and a steering direction Dsw of a steering wheel installed in the vehicle 200, a steering on signal SWon as a signal indicating that the steering wheel is held by the driver, vehicle peripheral information Iard, position information Ivp, navigation information Inavi, various setting signals Sset as signals indicating settings made by the driver in various controls, etc.).

[0125] Vehicle surrounding information sensor 86 includes, for example, at least one of a laser radar, a radar, and an onboard camera, and directly acquires information about the road on which the vehicle is traveling and about objects surrounding the vehicle. For example, vehicle surrounding information sensor 86 detects objects in front of, to the sides of, and behind vehicle 200, and outputs object information related to the detected objects as vehicle surrounding information Iard. This object information includes the distance and direction of the detected object from vehicle 200.

[0126] The vehicle position sensor 87 includes a GPS antenna, etc. The position information Ivp includes vehicle position information indicating the current position of the vehicle 200 on the ground or on a map based on GPS signals (orbital signals) transmitted by GPS (Global Positioning System) satellites.

[0127] Navigation system 88 is a well-known navigation system equipped with a display, speakers, and other components. Based on position information Ivp, navigation system 88 determines the vehicle's location on pre-stored map data. Upon receiving a destination input, navigation system 88 calculates a route from the departure point to the destination and provides the driver with route instructions using the display, speakers, and other components. Navigation information Inavi includes, for example, map information such as road information and facility information based on pre-stored map data in navigation system 88.

[0128] The various setting switch groups 89 include an automatic driving selection switch for executing the automatic driving control CTad, a cruise switch for executing the cruise control CTcr, a switch for setting the vehicle speed in the cruise control CTcr, a switch for setting the inter-vehicle distance with the preceding vehicle in the cruise control CTcr, a switch for executing the lane keeping control for maintaining the set driving lane, etc.

[0129] The various setting switch group 89 also includes an EV drive switch for executing control to continue the EV drive mode, in contrast to switching between the EV drive mode and the HV drive mode based on the presence or absence of a start request for the engine 12 as determined by the engine control unit 92a. The normal mode, which is executed when the EV drive switch is not operated, includes a charge sustaining mode, in which the engine is intermittently operated and EV driving using only the electric motor MG as the driving force source is possible with the engine 12 stopped. The charge sustaining mode is a CS (Charge Sustaining) mode for driving while maintaining the battery 54's state of charge (SOC) at a target value. The driving mode in which control to continue the EV drive mode is executed allows EV driving even when the battery 54's state of charge (SOC) is less than the engine start threshold (SOCengf). It is also a charge depleting mode that allows EV driving to continue longer than in the charge sustaining mode. The charge depleting mode is a CD (Charge Depleting) mode for driving while reducing the battery 54's SOC. As described above, the running mode includes a charge amount maintaining mode and a charge amount consuming mode. When the EV running switch is operated, the running mode control unit 96 outputs a command to the hybrid control unit 92 and the like to implement the charge amount consuming mode.

[0130] The shift operation position POSsh includes, for example, a B operation position in addition to the P, R, N, and D operation positions. The B operation position is an engine brake operation position that selects an engine brake mode in which the engine brake torque TBe is applied during deceleration of the vehicle 200 in the D position of the automatic transmission 24.

[0131] Braking torque TB of vehicle 200 is generated, for example, by regenerative braking torque TBr, wheel brake torque TBw, and engine brake torque TBe. Regenerative braking torque TBr is braking torque TB obtained by utilizing regenerative braking of the electric motor MG. Regenerative control for regenerating the electric motor MG involves rotating and driving the electric motor MG using driven torque input from the rear wheels 16, etc., to operate as a generator, and charging the generated power to the battery 54 via the inverter 52. Wheel brake torque TBw is braking torque TB obtained by utilizing the wheel brakes of the wheel brake device 66. Engine brake torque TBe is braking torque TB obtained by engine braking utilizing rotational resistance such as pumping loss and friction torque associated with the driven rotation of the engine 12.

[0132] For example, from the perspective of improving energy efficiency, the braking torque TB of vehicle 200 is preferentially generated by regenerative braking torque TBr. The hybrid control unit 92 outputs an MG control command signal Sm to the inverter 52 for executing regenerative control using the electric motor MG so as to obtain the regenerative torque required for regenerative braking torque TBr. For example, immediately before vehicle 200 stops, the hybrid control unit 92 replaces the braking torque TB using regenerative braking torque TBr with wheel brake torque TBw. The hybrid control unit 92 outputs a brake control command signal Sbra to the wheel brake device 66 for obtaining the required wheel brake torque TBw.

[0133] When the shift operation position POSsh is in the B operation position and the engine brake mode is selected as the driving mode, the driving mode control unit 96 outputs a command to the hybrid control unit 92 and the hydraulic control unit 94 to engage or slip the K0 clutch 20 during deceleration of the vehicle 200, thereby generating the engine brake torque TBe in addition to or instead of the regenerative brake torque TBr. Furthermore, when the shift operation position POSsh is not in the B operation position, the regenerative brake mode is selected as the driving mode, which prioritizes the regenerative brake torque TBr over the engine brake torque TBe during deceleration. Thus, the driving mode includes both the engine brake mode and the regenerative brake mode.

[0134] The electronic control device 90 outputs various command signals (eg, a steering control command signal Sste for controlling the steering of wheels (particularly, the front wheels 14 )) to various devices provided in the vehicle 200 (eg, the steering device 69 ).

[0135] The steering device 69 applies an assist torque corresponding to, for example, the vehicle speed V, the steering angle θsw, the steering direction Dsw, the yaw rate Ryaw, etc., to the steering system of the vehicle 200. In the steering device 69, for example, during the automatic driving control CTad, a torque for controlling the steering of the front wheels is applied to the steering system of the vehicle 200.

[0136] The electronic control device 90 further includes a driving control unit 98 , which serves as a driving control means, in order to implement various controls in the vehicle 200 .

[0137] The drive request amount for the vehicle 200 is, for example, the drive request amount output by the driver to the vehicle 200 during manual driving control CTmd, or the drive request amount for the vehicle 200 requested by the driving support control CTsd during driving support control CTsd.

[0138] For example, during manual driving control CTmd, hybrid control unit 92 calculates driver-requested driving force Frdemd as the driver's requested driving force for vehicle 200 by applying accelerator opening angle θacc and vehicle speed V to the requested driving force map. For example, during driving support control CTsd, hybrid control unit 92 calculates system-requested driving force Frdems as the requested driving force for vehicle 200 requested by driving support control CTsd. Requested driving force Frdem, requested driving torque Trdem, requested driving power Prdem, and the like can be converted into one another.

[0139] In the driving control unit 98, as driving control of the vehicle 200, manual driving control CTmd for driving the vehicle 200 according to the driver's driving operation and driving support control CTsd for driving the vehicle 200 by automatically performing at least one of acceleration, deceleration, braking, and steering without relying on the driver's driving operation can be executed.

[0140] Manual driving control CTmd is a driving control method for driving by manual driving using the driver's driving operation. This manual driving method is a driving method for normal driving of the vehicle 200 by the driver's driving operation such as acceleration operation, braking operation, and steering operation.

[0141] Driving assistance control CTsd, for example, involves driving support driving by automatically supporting part or all of the driver's driving operations. This driving assistance refers to a driving method in which the vehicle 200 is driven independently of the driver's driving operations, using control by the electronic control unit 90 based on signals and information from various sensors to automatically perform all or part of the acceleration, deceleration, braking, and steering functions. Driving assistance control CTsd, for example, involves autonomous driving control CTad, which automatically sets a target driving state based on a destination input by the driver, map information, and the like, and automatically performs acceleration, deceleration, braking, and steering functions based on that target driving state. Alternatively, driving assistance control CTsd includes, for example, automatic vehicle speed control CTas, which controls the vehicle speed V independently of the accelerator opening θacc. Automatic vehicle speed control CTas, for example, is the well-known cruise control CTcr, which automatically performs acceleration, deceleration, braking, and other functions based on the driver's partial driving operations, such as steering. Alternatively, the automatic vehicle speed control CTas is, for example, a well-known automatic vehicle speed limiter control (ASL (Adjustable Speed ​​Limiter)) that controls the driving force Fr so that the vehicle speed V does not exceed a target vehicle speed set by the driver.

[0142] When the automatic driving selection switch, cruise switch, etc., in the various setting switch group 89 are turned off and driving with driving support is not selected, the driving control unit 98 establishes the manual driving mode and executes manual driving control CTmd. For example, the driving control unit 98 outputs commands to the hybrid control unit 92 and the hydraulic control unit 94, etc., for controlling the engine 12, the electric motor MG, the automatic transmission 24, etc., based on the driver's operation, thereby executing the manual driving control CTmd.

[0143] When the driver selects automatic driving by operating the automatic driving select switch in the various setting switches 89, the driving control unit 98 establishes the automatic driving mode and executes automatic driving control CTad. Specifically, the driving control unit 98 automatically sets a target driving state based on the driver's input destination, vehicle position information based on position information Ivp, map information based on navigation information Inavi, and various information about the driving route based on vehicle periphery information Iard. The driving control unit 98 outputs commands to the hybrid control unit 92 and the hydraulic control unit 94, etc., to control the engine 12, electric motor MG, automatic transmission 24, etc., so that acceleration, deceleration, braking, and steering are automatically performed according to the set target driving state. Furthermore, the driving control unit 98 outputs a braking control command signal Sbra to the wheel brake device 66 for obtaining the necessary braking torque, and a steering control command signal Sste to the steering device 69 for controlling the steering of the front wheels, thereby executing automatic driving control CTad.

[0144] Here, in the first embodiment, the control for changing the engine operating condition REQeng when the AWD mode is selected and the towing mode is selected is exemplified. If there are multiple types of towing modes, the control for changing the engine operating condition REQeng within the towing mode may also be performed.

[0145] Specifically, in this embodiment, the driving modes include a first towing mode, which is a driving mode in which the vehicle travels while being towed by a towing vehicle, and a second towing mode, which is a driving mode different from the first towing mode and is also a driving mode in which the vehicle travels while being towed by a towing vehicle. That is, in this embodiment, the towing modes include the first towing mode and the second towing mode. Furthermore, the engine operating condition REQeng is predetermined so that the engine 12 operation ratio Reng is higher when the first towing mode is selected than when the second towing mode is selected.

[0146] In the first towing mode, it is preferable to reliably secure the required driving force Fr by starting the engine 12 earlier than in the second towing mode. Therefore, the engine operating conditions REQeng include, for example, an engine start condition for starting the engine 12 from the time the first towing mode is selected when the vehicle 200 is in the predetermined state STvf. Furthermore, the engine operating conditions REQeng include, for example, an engine start condition for starting the engine 12 from the time a predetermined request REQvf is issued in the vehicle 200 after the second towing mode is selected when the vehicle 200 is in the predetermined state STvf. The acceleration request for increasing the driving force Fr in the predetermined request REQvf may be, for example, an increase in the driver's requested driving force Frdemd or an increase in the system's requested driving force Frdems.

[0147] When the gross weight of the towed vehicle is light, a higher driving force Fr is not necessarily required compared to when it is heavy. Therefore, the second towing mode is selected when the gross weight of the towed vehicle is even lighter than in the first towing mode. In this case, for example, the driver can select the first towing mode and the second towing mode by operating a towing selector switch 81, which includes a lightweight towing selector switch and a heavy towing selector switch. Alternatively, for example, the electronic control unit 90 can automatically select the first towing mode and the second towing mode based on the accelerator opening θacc and the longitudinal acceleration Gx during towing mode selection.

[0148] Alternatively, the system-requested driving force Frdems during driving support control CTsd tends to have a greater degree of freedom than the driver-requested driving force Frdemd during manual driving control CTmd. On the other hand, even if acceleration responsiveness decreases during driving support control CTsd, it is less likely to be a problem compared to manual driving control CTmd. Therefore, the first towing mode is the towing mode selected when manual driving control CTmd is in effect. Furthermore, the second towing mode is the towing mode selected when driving support control CTsd is in effect.

[0149] Alternatively, the charge level maintenance mode is a driving mode that simultaneously maintains power performance and energy efficiency by switching between EV and HV driving modes. Meanwhile, the charge level consumption mode is a driving mode that makes it easier to continue EV driving than in the charge level maintenance mode and prioritizes energy efficiency over power performance. Therefore, the first towing mode is the towing mode selected when the charge level maintenance mode is in effect. Furthermore, the second towing mode is the towing mode selected when the charge level consumption mode is in effect.

[0150] Alternatively, engine braking mode is a driving mode that utilizes engine braking torque TBe to achieve a higher braking torque TB than regenerative braking mode, but requires the engine 12 to be kept rotating. On the other hand, regenerative braking mode is a driving mode that improves energy efficiency by disabling engine braking torque TBe. Therefore, the first towing mode is selected when engine braking mode is selected. Furthermore, the second towing mode is selected when regenerative braking mode is selected.

[0151] Alternatively, when AWD mode is selected, a greater driving force Fr is likely required compared to when 2WD mode is selected. On the other hand, when 2WD mode is selected, a greater driving force Fr may not necessarily be required. Therefore, the first towing mode is the towing mode selected when AWD mode is selected. Furthermore, the second towing mode is the towing mode selected when 2WD mode is selected.

[0152] As described above, basically, the first towing mode is a towing mode that prioritizes power performance, and the second towing mode is a towing mode that prioritizes energy efficiency.

[0153] Figure 5 This is a flowchart explaining a main part of the control operation of the electronic control device 90 , and is a flowchart explaining a control operation for suppressing a decrease in drivability and improving energy efficiency, and is executed repeatedly, for example. Figure 5 is with Figure 3 Flowcharts of different embodiments.

[0154] exist Figure 5 First, in S10b corresponding to the function of the driving mode control unit 96, it is determined whether the towing mode is selected. If the determination in S10b is negative, this routine ends. If the determination in S10b is positive, in S20b corresponding to the function of the driving mode control unit 96, it is determined whether the towing mode is the first towing mode. If the determination in S20b is positive, in S30b corresponding to the function of the engine control unit 92a, the operating state of the engine 12 is controlled based on the engine operating condition REQeng when the first towing mode is selected. If the determination in S20b is negative, in S40b corresponding to the function of the engine control unit 92a, the operating state of the engine 12 is controlled based on the engine operating condition REQeng when the second towing mode is selected.

[0155] As described above, according to this embodiment, the engine operating condition REQeng is predetermined so that the engine 12 operation ratio Reng is higher when the first towing mode is selected than when the second towing mode is selected. This facilitates ensuring sufficient driving force Fr when the first towing mode is selected, and facilitates improving energy efficiency when the second towing mode is selected. In other words, even in the towing mode, which requires a high driving force Fr for starting or accelerating, it is possible to increase the number of situations in which the engine 12 is stopped. This allows for improved energy efficiency while minimizing degradation in drivability.

[0156] Furthermore, according to this embodiment, the second towing mode is a towing mode selected when the total weight of the towed vehicle is lighter than in the first towing mode. Therefore, in the second towing mode, which places less emphasis on power performance than in the first towing mode, it is possible to increase the number of situations in which the engine 12 is stopped.

[0157] Furthermore, according to this embodiment, the first towing mode is the towing mode selected when the manual driving control CTmd is executed, and the second towing mode is the towing mode selected when the driving support control CTsd is executed. Therefore, even in the towing mode, when the driving support control CTsd is executed, which has a greater degree of freedom in requesting the driving force Fr than the manual driving control CTmd, the situation in which the engine 12 is brought to a stopped state can be increased.

[0158] In addition, according to this embodiment, the first towing mode is a towing mode selected when the charge amount maintenance mode is executed, and the second towing mode is a towing mode selected when the charge amount consumption mode that can continue EV driving better than the charge amount maintenance mode is executed. Therefore, even in the towing mode, when the charge amount consumption mode that emphasizes energy efficiency rather than power performance is executed compared to the charge amount maintenance mode, it is possible to increase the situation where the engine 12 is put into a stopped state.

[0159] Furthermore, according to this embodiment, the first towing mode is a towing mode selected when the engine braking mode is selected, and the second towing mode is a towing mode selected when the regenerative braking mode is selected. Therefore, even in the towing mode, when the regenerative braking mode is selected, which prioritizes energy efficiency over the engine braking mode that requires the engine 12 to be kept in a rotating state, it is possible to increase the number of situations in which the engine 12 is stopped.

[0160] In addition, according to this embodiment, the first towing mode is the towing mode selected when the AWD mode is selected, and the second towing mode is the towing mode selected when the 2WD mode is selected. Therefore, even in the towing mode, when the 2WD mode is selected, which does not place much emphasis on power performance compared to the selection of the AWD mode, it is possible to increase the situation in which the engine 12 is stopped.

[0161] [Example 3]

[0162] In the second embodiment described above, control for changing the engine operating condition REQeng when the first towing mode and the second towing mode are selected is exemplified. In the case where vehicle 200 has multiple types of towing modes instead of towing modes and multiple types of AWD modes, control for changing the engine operating condition REQeng within the AWD mode may also be performed.

[0163] Specifically, in this embodiment, the driving modes include a first AWD mode, which is a driving mode in which the driving force is distributed to both the rear wheels 16 and the front wheels 14, and a second AWD mode, which is a driving mode different from the first AWD mode, in which the driving force is distributed to both the rear wheels 16 and the front wheels 14. That is, in this embodiment, the AWD modes include the first AWD mode and the second AWD mode. Furthermore, the engine operating condition REQeng is predetermined so that when the first AWD mode is selected, the operating ratio Reng of the engine 12 is higher than when the second AWD mode is selected. In addition, when the AWD mode includes a low-range AWD mode and a high-range AWD mode, the first AWD mode and the second AWD mode also include a low-range AWD mode and a high-range AWD mode, respectively.

[0164] In the first AWD mode, it is preferable to reliably secure the required driving force Fr by starting the engine 12 earlier than in the second AWD mode. Therefore, the engine operating conditions REQeng include, for example, engine start conditions for starting the engine 12 from the time the first AWD mode is selected when the vehicle 200 is in the predetermined state STvf. Furthermore, the engine operating conditions REQeng include, for example, engine start conditions for starting the engine 12 from the time a predetermined request REQvf is issued in the vehicle 200 after the second AWD mode is selected when the vehicle 200 is in the predetermined state STvf. The acceleration request for increasing the driving force Fr in the predetermined request REQvf may be, for example, an increase in the driver-requested driving force Frdemd or an increase in the system-requested driving force Frdems.

[0165] The first AWD mode is an AWD mode selected when the manual driving control CTmd is executed, and the second AWD mode is an AWD mode selected when the driving support control CTsd is executed.

[0166] Alternatively, the first AWD mode is an AWD mode selected when the charge amount maintaining mode is executed, and the second AWD mode is an AWD mode selected when the charge amount depleting mode is executed.

[0167] Alternatively, the first AWD mode is an AWD mode selected when the engine brake mode is selected, and the second AWD mode is an AWD mode selected when the regenerative brake mode is selected.

[0168] Alternatively, when towing mode is selected, a high driving force Fr is definitely required during launch or acceleration. On the other hand, when towing mode is not selected, a high driving force Fr may not necessarily be required. Therefore, the first AWD mode is the AWD mode selected when towing mode is selected. Furthermore, the second AWD mode is the AWD mode selected when towing mode is not selected.

[0169] As described above, basically, the first AWD mode is an AWD mode that prioritizes power performance, and the second AWD mode is an AWD mode that prioritizes energy efficiency.

[0170] Figure 6 This is a flowchart explaining a main part of the control operation of the electronic control device 90 , and is a flowchart explaining a control operation for suppressing a decrease in drivability and improving energy efficiency, and is executed repeatedly, for example. Figure 6 is with Figure 3 、 Figure 5 Flowcharts of different embodiments.

[0171] exist Figure 6 First, in S10c, which corresponds to the function of the driving mode control unit 96, a determination is made as to whether the AWD mode is selected. If the determination in S10c is negative, this routine ends. If the determination in S10c is positive, in S20c, which corresponds to the function of the driving mode control unit 96, a determination is made as to whether the AWD mode is the first AWD mode. If the determination in S20c is positive, in S30c, which corresponds to the function of the engine control unit 92a, the operating state of the engine 12 is controlled based on the engine operating condition REQeng when the first AWD mode is selected. If the determination in S20c is negative, in S40c, which corresponds to the function of the engine control unit 92a, the operating state of the engine 12 is controlled based on the engine operating condition REQeng when the second AWD mode is selected.

[0172] As described above, according to this embodiment, the engine operating condition REQeng is predetermined so that the engine 12 operation ratio Reng is higher when the first AWD mode is selected than when the second AWD mode is selected. This facilitates ensuring sufficient driving force Fr when the first AWD mode is selected, while facilitating improved energy efficiency when the second AWD mode is selected. In other words, even in the AWD mode requiring a high driving force Fr, it is possible to increase the number of situations in which the engine 12 is stopped. Consequently, it is possible to suppress a decrease in drivability while improving energy efficiency.

[0173] Furthermore, according to this embodiment, the first AWD mode is the AWD mode selected when the manual driving control CTmd is executed, and the second AWD mode is the AWD mode selected when the driving support control CTsd is executed. Therefore, even in the AWD mode, when the driving support control CTsd is executed, which has a greater degree of freedom in requesting the driving force Fr than the manual driving control CTmd, the engine 12 can be brought into a stopped state.

[0174] In addition, according to this embodiment, the first AWD mode is the AWD mode selected when the charge amount maintenance mode is executed, and the second AWD mode is the AWD mode selected when the charge amount consumption mode is executed, which can continue EV driving better than the charge amount maintenance mode. Therefore, even in the AWD mode, when the charge amount consumption mode is executed, which emphasizes energy efficiency rather than power performance compared to the charge amount maintenance mode, it is possible to increase the situation where the engine 12 is stopped.

[0175] Furthermore, according to this embodiment, the first AWD mode is the AWD mode selected when the engine brake mode is selected, and the second AWD mode is the AWD mode selected when the regenerative brake mode is selected. Therefore, even in the AWD mode, when the regenerative brake mode is selected, which prioritizes energy efficiency over the engine brake mode that requires the engine 12 to be kept in a rotating state, the engine 12 can be brought to a stopped state in an increased number of situations.

[0176] In addition, according to this embodiment, the first AWD mode is the AWD mode selected when the towing mode is selected, and the second AWD mode is the AWD mode selected when the towing mode is not selected. Therefore, even in the AWD mode, when the towing mode is not selected, which does not place much emphasis on power performance compared to when the towing mode is selected, it is possible to increase the situation in which the engine 12 is stopped.

[0177] As mentioned above, although the embodiment of the present invention was described in detail based on the drawings, the present invention can also be applied in other aspects.

[0178] For example, in the above embodiment, the driving mode, such as the towing mode, 2WD mode, or AWD mode, is selected by the driver, but the present invention is not limited to this. For example, the electronic control unit 90 may automatically select a driving mode based on the accelerator opening θacc, the wheel speed Nr, the longitudinal acceleration Gx, the yaw rate Ryaw, and the like.

[0179] Furthermore, in the second embodiment, if the control for changing the engine operating condition REQeng between the selection of the AWD mode and the selection of the 2WD mode in the towing mode is not implemented, the vehicle 200 may be a 2WD vehicle, for example, without the drive switching dial switch 82, the transmission 26, the ADD mechanism 37, etc. In short, the vehicle 200 may be provided with the driving control, travel mode, etc. required according to the type of control for changing the engine operating condition REQeng in the towing mode.

[0180] Furthermore, in the third embodiment described above, if the control for changing the engine operating condition REQeng between when the towing mode is selected and when the towing mode is not selected in the AWD mode is not implemented, the vehicle 200 may not include the towing select switch 81, for example, and may not include the towing mode as a driving mode. In short, the vehicle 200 may only include the driving control, driving mode, etc. required according to the type of control for changing the engine operating condition REQeng in the AWD mode.

[0181] Furthermore, in the second and third embodiments described above, when vehicle 200 includes a charge level maintenance mode and a charge level consumption mode as driving modes, vehicle 200 may be a so-called plug-in hybrid vehicle in which battery 54 can be charged from an external power source such as a charging station or a household power source. Control that changes engine operating condition REQeng between charge level maintenance mode and charge level consumption mode is useful for plug-in hybrid vehicles.

[0182] In addition, in the above-mentioned embodiment, when the vehicle 10, 200 is equipped with a starter as a dedicated motor for starting the engine 12, when the vehicle 10, 200 is stopped with the MG speed Nm set to zero, for example, when starting the engine using the electric motor MG is insufficient or impossible 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.

[0183] In the above embodiment, a planetary gear type automatic transmission is exemplified as the automatic transmission 24, but the present invention is not limited to this type. The automatic transmission 24 may also be a synchronized meshing parallel two-axis automatic transmission including a known DCT (Dual Clutch Transmission), a known belt-type continuously variable transmission, or the like.

[0184] Furthermore, in the above-described embodiments, vehicles 10 and 200 are AWD vehicles based on 2WD vehicles with an FR configuration, and are parallel hybrid vehicles that transmit driving force from the engine 12 and the electric motor MG to the rear wheels 16, etc. However, the present invention is not limited to this configuration. For example, the present invention can also be applied to AWD vehicles based on 2WD vehicles with an FF (front engine / front drive) configuration, hybrid vehicles equipped with a conventional electric continuously variable transmission, or series hybrid vehicles that transmit driving force from an electric motor driven by power generated by a generator driven by engine power and / or power from a battery to the drive wheels. Alternatively, such series hybrid vehicles may not include an automatic transmission.

[0185] Furthermore, in the above-described embodiment, the AWD system is not limited to one comprising the transmission 26 and the ADD mechanism 37. For example, an AWD system in which the auxiliary drive wheels are driven by a separate electric motor from the main drive wheels is also possible. Alternatively, an AWD system in which the transmission 26 does not include the auxiliary transmission 106 and simply switches between 2WD mode and AWD mode is also possible. In this case, in the above-described first embodiment, the MG idling control for switching from the high-range AWD mode to the low-range AWD mode is not executed. Alternatively, in the above-described third embodiment, an AWD system in which the AWD mode is always active and does not include a 2WD mode is also possible.

[0186] Furthermore, in the above embodiment, a torque converter 22 is used as a fluid transmission device, but the present invention is not limited to this embodiment. For example, a fluid transmission device such as a fluid coupling without a torque amplification function may be used in place of the torque converter 22. Alternatively, a fluid transmission device need not necessarily be provided; for example, a clutch for starting the engine may be substituted.

[0187] The above is merely one embodiment, and the present invention can be implemented in various ways with modifications and improvements added based on the knowledge of those skilled in the art.

Claims

1. A control device (90) for a hybrid vehicle (10; 200), the hybrid vehicle (10; 200) comprising an engine (12), an electric motor (MG), and a driving force distribution device (26) for distributing driving force to a main driving wheel (16) and an auxiliary driving wheel (14), the control device (90) for the hybrid vehicle (10; 200) being characterized by comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (10; 200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving modes include a towing mode in which the vehicle is towed, 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). The engine operating condition is predetermined so that, when the towing mode is selected, the operating ratio (Reng) of the engine (12), which is the ratio of the operating time of the engine (12) to the operating time of the hybrid vehicle (10; 200), is higher than when the all-wheel drive mode is selected, The engine operation condition includes an engine start condition, wherein, when the towing mode is selected when the hybrid vehicle (10; 200) is in a predetermined state, the engine (12) is started from the time point of selection of the towing mode, and, on the other hand, when the all-wheel drive mode is selected when the hybrid vehicle (10; 200) is in the predetermined state, the engine (12) is started from the time point of a predetermined request in the hybrid vehicle (10; 200) after the all-wheel drive mode is selected. The predetermined state is a state in which the hybrid vehicle (10; 200) is stopped and the vehicle power transmission device (18) transmitting the driving force is set to a forward driving position capable of transmitting the forward driving force, or a state in which the output rotating member (48) of the vehicle power transmission device (18) is not mechanically fixed in a non-rotatable manner and is not able to transmit the driving force. The predetermined request is an acceleration request to increase the driving force or a charge request for a power storage device (54) that exchanges electric power with the electric motor (MG).

2. The control device (90) of the hybrid vehicle (10; 200) according to claim 1, characterized in that The engine operating condition is predetermined so that the operation ratio (Reng) of the engine (12) is higher when the towing mode is selected and when the all-wheel drive mode is selected than when the main drive wheel drive mode is selected and the towing mode is not selected.

3. The control device (90) of the hybrid vehicle (10; 200) according to claim 2, characterized in that The engine operation condition includes an engine intermittent operation condition, wherein the engine intermittent operation condition prohibits the engine (12) from switching between a running state and a stopped state when the towing mode is selected and when the all-wheel drive mode is selected, respectively, and on the other hand, permits the engine intermittent operation when the main drive wheel drive mode is selected and the towing mode is not selected.

4. The control device (90) of the hybrid vehicle (10; 200) according to claim 1, characterized in that The all-wheel drive mode includes a low-gear all-wheel drive mode in which a transmission (106) provided in the driving force distribution device (26) selectively forms a low gear and a high gear by the action of a bite clutch (120) and is set to the low gear, and a high-gear all-wheel drive mode in which the transmission (106) is set to the high gear, The main drive wheel driving mode is a high-gear main drive wheel driving mode in which the transmission (106) is set to the high gear position. The control device (90) of the hybrid vehicle (10; 200) further includes a motor control unit (92b) which, when controlling in the high-speed main drive wheel drive mode when both the engine (12) and the motor (MG) are set to a stopped state, outputs a predetermined torque for generating a creeping phenomenon from the motor (MG) while maintaining the stopped state of the engine (12) by selecting the high-speed all-wheel drive mode and switching from the high-speed main drive wheel drive mode to the high-speed all-wheel drive mode.

5. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12) and a motor (MG), the control device (90) for the hybrid vehicle (200) being characterized by comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first towing mode in which the vehicle is towed by a towing vehicle and a second towing mode different from the first towing mode in which the vehicle is towed by the towing vehicle. The engine operation condition is predetermined so that when the first towing mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second towing mode is selected, The second towing mode is a towing mode selected when the total weight of the towed vehicle is lighter than that in the first towing mode.

6. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12) and a motor (MG), the control device (90) for the hybrid vehicle (200) comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first towing mode in which the vehicle is towed by a towing vehicle and a second towing mode different from the first towing mode in which the vehicle is towed by the towing vehicle. The engine operation condition is predetermined so that when the first towing mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second towing mode is selected, The control device (90) further includes a driving control unit (98) capable of executing manual driving control for driving the hybrid vehicle (200) according to the driver's driving operation and driving support control for driving the hybrid vehicle (200) by at least automatically performing acceleration and deceleration. The first towing mode is a towing mode selected when the manual driving control is executed. The second towing mode is a towing mode selected when the driving support control is executed.

7. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12) and a motor (MG), the control device (90) for the hybrid vehicle (200) comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first towing mode in which the vehicle is towed by a towing vehicle and a second towing mode different from the first towing mode in which the vehicle is towed by the towing vehicle. The engine operation condition is predetermined so that when the first towing mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second towing mode is selected, The driving mode includes a charge amount maintenance mode in which the engine (12) is switched between a running state and a stopped state and motor driving using only the electric motor (MG) as a driving force source is possible when the engine (12) is stopped, and a charge amount consumption mode in which the motor driving can be continued longer than in the charge amount maintenance mode. The first towing mode is a towing mode selected when the charge amount maintaining mode is executed. The second towing mode is a towing mode selected when the charge amount depletion mode is executed.

8. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12) and a motor (MG), the control device (90) for the hybrid vehicle (200) comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first towing mode in which the vehicle is towed by a towing vehicle and a second towing mode different from the first towing mode in which the vehicle is towed by the towing vehicle. The engine operation condition is predetermined so that when the first towing mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second towing mode is selected, The driving mode includes an engine braking mode in which an engine braking torque based on the rotational resistance of the engine (12) is applied during deceleration driving, and a regenerative braking mode in which a regenerative braking torque based on the regeneration of the electric motor (MG) is applied preferentially over the engine braking torque during deceleration driving. The first towing mode is a towing mode selected when the engine brake mode is selected. The second towing mode is a towing mode selected when the regenerative braking mode is selected.

9. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12) and a motor (MG), the control device (90) for the hybrid vehicle (200) comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first towing mode in which the vehicle is towed by a towing vehicle and a second towing mode different from the first towing mode in which the vehicle is towed by the towing vehicle. The engine operation condition is predetermined so that when the first towing mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second towing mode is selected, The driving modes include an all-wheel drive mode in which the vehicle travels by distributing the driving force to both the main drive wheel (16) and the auxiliary drive wheel (14) through a driving force distribution device (26) for distributing the driving force to the main drive wheel (16) and the auxiliary drive wheel (14), and a main drive wheel drive mode in which the vehicle travels by distributing the driving force only to the main drive wheel (16). The first towing mode is a towing mode selected when the all-wheel drive mode is selected. The second towing mode is a towing mode selected when the main drive wheel drive mode is selected.

10. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12), an electric motor (MG), and a driving force distribution device (26) for distributing driving force to a main driving wheel (16) and an auxiliary driving wheel (14), the control device (90) for the hybrid vehicle (200) being characterized by comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14) for driving, and a second all-wheel drive mode different from the first all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14) for driving, The engine operation condition is predetermined so that when the first all-wheel drive mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second all-wheel drive mode is selected, The control device (90) further includes a driving control unit (98) capable of executing manual driving control for driving the hybrid vehicle (200) according to the driver's driving operation, and driving support control for driving the hybrid vehicle (200) by at least automatically performing acceleration and deceleration. The first all-wheel drive mode is an all-wheel drive mode selected when the manual driving control is executed. The second all-wheel drive mode is an all-wheel drive mode selected when the driving support control is executed.

11. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12), a motor (MG), and a driving force distribution device (26) for distributing driving force to a main driving wheel (16) and a secondary driving wheel (14), wherein the control device (90) for the hybrid vehicle (200) is characterized by comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14) for driving, and a second all-wheel drive mode different from the first all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14) for driving, The engine operation condition is predetermined so that when the first all-wheel drive mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second all-wheel drive mode is selected, The driving mode includes a charge amount maintenance mode in which the engine (12) is switched between a running state and a stopped state and motor driving using only the electric motor (MG) as a driving force source is possible when the engine (12) is stopped, and a charge amount consumption mode in which the motor driving can be continued longer than in the charge amount maintenance mode. The first all-wheel drive mode is an all-wheel drive mode selected when the charge level maintaining mode is executed. The second all-wheel drive mode is an all-wheel drive mode selected when the charge amount depletion mode is executed.

12. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12), a motor (MG), and a driving force distribution device (26) for distributing driving force to a main driving wheel (16) and a secondary driving wheel (14), wherein the control device (90) for the hybrid vehicle (200) is characterized by comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14) for driving, and a second all-wheel drive mode different from the first all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14) for driving, The engine operation condition is predetermined so that when the first all-wheel drive mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second all-wheel drive mode is selected, The driving mode includes an engine braking mode in which an engine braking torque based on the rotational resistance of the engine (12) is applied during deceleration driving, and a regenerative braking mode in which a regenerative braking torque based on the regeneration of the electric motor (MG) is applied preferentially over the engine braking torque during deceleration driving. The first all-wheel drive mode is an all-wheel drive mode selected when the engine brake mode is selected. The second all-wheel drive mode is an all-wheel drive mode selected when the regenerative braking mode is selected.

13. A control device (90) for a hybrid vehicle (200), the hybrid vehicle (200) comprising an engine (12), a motor (MG), and a driving force distribution device (26) for distributing driving force to a main driving wheel (16) and a secondary driving wheel (14), wherein the control device (90) for the hybrid vehicle (200) is characterized by comprising: An engine control unit (92a) controls an operating state of the engine (12) based on a predetermined engine operating condition for starting or stopping the engine (12); as well as A driving mode control unit (96) controls the driving of the hybrid vehicle (200) in a manner that realizes a driving mode selected by a driver or automatically selected. The driving mode includes a first all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14) for driving, and a second all-wheel drive mode different from the first all-wheel drive mode in which the driving force is distributed to both the main drive wheel (16) and the auxiliary drive wheel (14) for driving, The engine operation condition is predetermined so that when the first all-wheel drive mode is selected, the operation ratio (Reng) of the engine (12), which is the ratio of the operation time of the engine (12) to the operation time of the hybrid vehicle (200), is higher than when the second all-wheel drive mode is selected, The driving mode includes a towing mode in which the vehicle is towed by the towing vehicle. The first all-wheel drive mode is an all-wheel drive mode selected when the towing mode is selected. The second all-wheel drive mode is an all-wheel drive mode selected when the towing mode is not selected.

Images