Vehicle control apparatus

Abstract

To provide a vehicle control apparatus that can easily secure drive torque while suppressing unnecessary downshift when performing sports run.SOLUTION: When a shift position of an automatic transmission is at a forward travel position, it is determined that sports run is being performed. and if it is determined that a permission condition holds, downshift of the automatic transmission is executed. By so doing, downshift is executed while sports run is being executed, making it easy to secure drive torque. Furthermore, since this is limited to a case where the permission condition holds, downshift is not executed in a state where lateral slip suppression control is in operation, for example. Therefore, in executing sports run, it is possible to easily secure drive torque while suppressing unnecessary downshift. Control of vehicle attitude is facilitated while sports run is being executed. Furthermore, acceleration performance upon a start-up after turning is improved.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device that executes control during sports driving, in which the vehicle is driven in a skidding state when cornering. [Background technology]

[0002] Control devices for vehicles that include a power source and an automatic transmission provided in a power transmission path between the power source and drive wheels are well known. For example, a vehicle control device is described in Patent Document 1. Patent Document 1 discloses that a vehicle that includes an engine and a stepped transmission mechanism downshifts when sudden deceleration is required. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-157456 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the technology described in Patent Document 1, a lower vehicle speed gear can be achieved by downshifting during heavy braking before entering a corner. However, during sporty driving, in which the vehicle skids while cornering, the vehicle speed and engine speed may drop to a low range. In this case, depending on the driving conditions during sporty driving, the vehicle may not enter a range where a downshift is required, and a downshift may not be performed. This may result in the drive wheels gripping the road due to insufficient drive torque, making it difficult to maintain the vehicle's posture, such as a skid, during sporty driving. Furthermore, after cornering, the vehicle may accelerate from a state of insufficient drive torque, resulting in poor re-acceleration.

[0005] The present invention was made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can easily ensure driving torque while suppressing unnecessary downshifts when performing sporty driving. [Means for solving the problem]

[0006] The gist of the first invention is that it is a control device for a vehicle that has (a) a power source and an automatic transmission provided in a power transmission path between the power source and drive wheels, and includes: (b) a sports driving determination unit that determines whether or not the vehicle is performing sports driving, which causes the vehicle to travel in a skid state when turning; (c) a condition satisfaction determination unit that determines whether or not a permission condition is met, in which the vehicle speed is less than a predetermined vehicle speed and the operation of skid suppression control is restricted; and (d) a transmission control unit that determines that the sports driving is being performed when the shift position of the automatic transmission is a forward driving position that executes automatic shift control to enable forward driving, and that downshifts the automatic transmission if it is determined that the permission condition is met. [Effects of the Invention]

[0007] According to the first aspect of the present invention, when the shift position of the automatic transmission is in a forward driving position, if it is determined that sporty driving is being performed and if it is determined that the permission conditions are met, the automatic transmission downshifts. This allows downshifts to be performed while sporty driving is being performed, making it easier to ensure drive torque. Furthermore, since downshifts are performed only when the permission conditions are met, downshifts are not performed when, for example, sideslip suppression control is active. Therefore, when sporty driving is being performed, it is easier to ensure drive torque while suppressing unnecessary downshifts. This makes it easier to control the vehicle posture while sporty driving is being performed. Furthermore, acceleration performance when accelerating after cornering is improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and control systems for various controls in the vehicle. [Figure 2] This is a flowchart that explains the main control operations of the electronic control device, and explains the control operations to make it easier to ensure driving torque while suppressing unnecessary downshifts when performing drift driving. [Figure 3] 3 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 2 is executed. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0010] Fig. 1 is a diagram illustrating the schematic configuration of a vehicle 10 to which the present invention is applied, and also illustrates the main parts of the control functions and control systems for various controls in the vehicle 10. In Fig. 1, the vehicle 10 is equipped with an engine 12 as a power source, drive wheels 14, and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14.

[0011] The engine 12 is a known internal combustion engine. The engine 12 has an engine control device 50, which is provided in the vehicle 10 and includes an electronic throttle valve, a fuel injection device, an ignition device, etc., and is controlled by an electronic control device 90, which will be described later, to control the engine torque Te of the engine 12.

[0012] The power transmission device 16 includes a torque converter 20 connected to the engine 12, an automatic transmission 22 connected to the torque converter 20, and the like, housed within a case 18, which is a non-rotating member attached to the vehicle body. The power transmission device 16 also includes a propeller shaft 26 connected to a transmission output shaft 24, a differential gear 28 connected to the propeller shaft 26, and a pair of drive shafts 30 connected to the differential gear 28. The transmission output shaft 24 is an output rotating member of the automatic transmission 22. The power transmission device 16 also includes an engine connecting shaft 32 that connects the engine 12 and the torque converter 20, and the like.

[0013] The torque converter 20 is a known fluid-type power transmission device. The torque converter 20 includes a pump wheel 20p connected to an engine connecting shaft 32 and a turbine wheel 20t connected to a transmission input shaft 34. The transmission input shaft 34 is an input rotating member of the automatic transmission 22.

[0014] The torque converter 20 includes an LU clutch 36 as a direct-coupled clutch that couples the engine connecting shaft 32 and the transmission input shaft 34. The LU clutch 36 is a known lock-up clutch, such as a hydraulic friction engagement device. The LU clutch 36 switches between operating states, i.e., control states, such as an engaged state, a slip state, and a disengaged state, by changing the LU torque Tlu, which is the torque capacity of the LU clutch 36, using the LU oil pressure PRlu. The LU oil pressure PRlu is the oil pressure of the adjusted oil FLD supplied to the LU clutch 36 from a hydraulic control circuit 52 provided in the vehicle 10. The oil FLD is hydraulic oil used for the gear shifting operation of the automatic transmission 22 and the switching operation of the LU clutch 36.

[0015] The automatic transmission 22 is a known planetary gear type automatic transmission that includes, for example, one or more planetary gear sets (not shown) and an engagement device CB. The engagement device CB is a known hydraulic friction engagement device that includes multiple engagement devices, such as clutches and brakes. The engagement device CB switches between control states such as an engaged state, a slip state, and a released state by changing an engagement torque Tcb, which is the torque capacity of the engagement device CB, using an engagement hydraulic pressure PRcb. The engagement hydraulic pressure PRcb is the hydraulic pressure of the adjusted oil FLD supplied to the engagement device CB from a hydraulic control circuit 52.

[0016] The automatic transmission 22 is a stepped transmission in which one of a plurality of gear stages (also referred to as gear stages GS) with different speed ratios (also referred to as gear ratios) γat (=Ni / No) is formed by engaging one of the engagement devices CB. "Ni" is the rotational speed of the transmission input shaft 34, and is the input rotational speed of the automatic transmission 22, i.e., the transmission input rotational speed Ni. "No" is the rotational speed of the transmission output shaft 24, and is the output rotational speed of the automatic transmission 22, i.e., the transmission output rotational speed No.

[0017] The automatic transmission 22 switches between the gear stages GS that are implemented by switching the control state of the engagement devices CB using an electronic control device 90, which will be described later, in response to the accelerator operation of the driver, the vehicle speed V, and the like. During the gear shifting operation of the automatic transmission 22, a so-called clutch-to-clutch gear shift is performed, in which the gear shift progresses by, for example, disengaging a release-side engagement device while engaging an engagement-side engagement device. The release-side engagement device is an engagement device involved in the gear shift that was in an engaged state before the automatic transmission 22 shifted, and is a release-side engagement device that is controlled from an engaged state to a released state during a gear shift transition of the automatic transmission 22. The engagement-side engagement device is an engagement device involved in the gear shift that was in a disengaged state before the automatic transmission 22 shifted, and is an engagement-side engagement device that is controlled from a released state to an engaged state during a gear shift transition of the automatic transmission 22.

[0018] The vehicle 10 is equipped with a mechanical oil pump 38 connected to the pump impeller 20p. The oil pump 38 is driven to rotate by the engine 12, thereby discharging oil FLD used in the power transmission device 16. The oil FLD discharged from the oil pump 38 is supplied to a hydraulic control circuit 52. The hydraulic control circuit 52 supplies LU hydraulic pressure PRlu and various engagement hydraulic pressures PRcb, which are adjusted based on the oil FLD from the oil pump 38.

[0019] The vehicle 10 is equipped with a wheel brake device 54. The wheel brake device 54 includes a brake master cylinder and a cylinder actuator (not shown) that generate brake hydraulic pressure. Each of the wheels WH, including the drive wheels 14 and the driven wheels 15, is equipped with a wheel brake 56. If the vehicle 10 is an all-wheel drive vehicle, the driven wheels are the drive wheels. The wheel brake device 54 applies a wheel braking torque Tb, which is a braking torque generated by the wheel brakes 56, to the wheels WH in accordance with a command from an electronic control device 90 (described later). The wheel brake device 54 supplies brake hydraulic pressure to wheel cylinders (not shown) provided in the wheel brakes 56 in response to, for example, the driver's depression of the brake pedal. In the wheel brake device 54, under normal conditions, a master cylinder hydraulic pressure corresponding to a brake operation amount Bra generated by the brake master cylinder is supplied to the wheel cylinder as brake hydraulic pressure. The brake operation amount Bra is a signal that corresponds to the brake pedal depression force and indicates the magnitude of the brake pedal depression operation by the driver, i.e., the magnitude of the brake operation. On the other hand, in the wheel brake device 54, for example, when VSC or automatic brake control is activated, brake oil pressure of a magnitude corresponding to the wheel braking torque Tb required for each control is supplied to the wheel cylinder in order to generate the wheel braking torque Tb.

[0020] VSC (Vehicle Stability Control) is a well-known skid suppression control system that controls the wheel braking torque Tb and driving torque Td of each wheel WH to suppress rear wheel skid or front wheel skid in order to ensure stability in the turning direction of the vehicle 10.

[0021] The vehicle 10 further includes an electronic control device 90 as a controller including control devices for the vehicle 10 related to the control of the engine 12 and the automatic transmission 22. The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc. The CPU executes various controls of the vehicle 10 by, for example, utilizing the temporary storage function of the RAM and performing signal processing in accordance with programs stored in the ROM in advance. The electronic control device 90 includes computers for engine control, hydraulic control, brake control, etc. as necessary.

[0022] The electronic control device 90 is supplied with various signals based on detection values ​​from various sensors provided in the vehicle 10. The various sensors include, for example, an engine rotation speed sensor 60, an input rotation speed sensor 62, an output rotation speed sensor 64, an accelerator opening sensor 66, a brake sensor 68, an acceleration sensor 70, a yaw rate sensor 72, a steering sensor 74, an operation position sensor 76, and an oil temperature sensor 78. The various signals include, for example, an engine rotation speed Ne, a transmission input rotation speed Ni, a transmission output rotation speed No, an accelerator opening θacc, a brake-on signal Bon, a brake operation amount Bra, a longitudinal acceleration Gx, a lateral acceleration Gy, a yaw rate Ryaw, a steering angle θsw, a steering direction Dsw, an operation position POSop, and an oil temperature THfld.

[0023] The engine rotation speed Ne is the rotation speed of the engine 12. The transmission input rotation speed Ni is equal to the turbine rotation speed Nt, which is the rotation speed of the turbine wheel 20t. The transmission output rotation speed No is the rotation speed corresponding to the vehicle speed V. The accelerator opening θacc is the amount of accelerator operation by the driver, which indicates the magnitude of the driver's acceleration operation. The brake-on signal Bon is a signal indicating the state in which the brake pedal for operating the wheel brakes 56 is being operated by the driver. The yaw rate Ryaw is the rotational angular velocity around the vertical axis of the vehicle 10. The steering angle θsw is the steering angle of the steering wheel (not shown) provided on the vehicle 10. The steering direction Dsw is the steering direction of the steering wheel. The oil temperature THfld is the temperature of the oil FLD.

[0024] The vehicle 10 is equipped with a shift device 80 having a shift operating member that is operated by the driver to one of a plurality of operating positions POSop. The shift device 80 is a switching device for switching the shift position (including the shift range Rsh) of the automatic transmission 22. The operating position POSop is a signal that indicates the selected state of the power transmission state in the automatic transmission 22, and includes, for example, P, R, N, and D operating positions. The shift range Rsh indicates the power transmission state of the automatic transmission 22, and includes, for example, P, R, N, and D ranges.

[0025] The P (parking) operating position represents the selected state of the P range of the automatic transmission 22, in which the automatic transmission 22 is in a neutral state and the transmission output shaft 24 is mechanically fixed so as not to rotate. The neutral state of the automatic transmission 22 is a state in which power cannot be transmitted and no gear stage GS is formed. The R (reverse) operating position represents the selected state of the R range of the automatic transmission 22, which enables reverse driving. The N (neutral) operating position represents the selected state of the N range of the automatic transmission 22, in which the automatic transmission 22 is in a neutral state. The D (forward driving) operating position represents the selected state of the D range of the automatic transmission 22, which executes automatic shift control of the automatic transmission 22 to enable forward driving. The D range of the automatic transmission 22 is the forward driving position (the same applies to the forward driving range) of the automatic transmission 22.

[0026] The vehicle 10 further includes a mode selection switch 82. The mode selection switch 82 is a switch that is operated by the driver to set the drive mode MODEdr of the vehicle 10. The drive mode MODEdr includes, for example, normal mode, sport mode (i.e., power mode), and eco mode. The normal mode is a predetermined drive mode for driving the vehicle in an energy-efficient state while extracting power performance. The sport mode is a predetermined drive mode for driving the vehicle in a state where power performance is prioritized over energy efficiency compared to the normal mode. The eco mode is a predetermined drive mode for driving the vehicle in a state where energy efficiency is prioritized over power performance compared to the normal mode.

[0027] The mode selection switch 82 includes a sport mode switch 84 and an eco mode switch 86 for switching the drive mode MODEdr. The sport mode switch 84 is a switch for setting sport mode as the drive mode MODEdr. The eco mode switch 86 is a switch for setting eco mode as the drive mode MODEdr. A signal of the drive mode MODEdr detected by the mode selection switch 82 is supplied to the electronic control unit 90. When neither the sport mode switch 84 nor the eco mode switch 86 is operated, normal mode is set as the drive mode MODEdr.

[0028] The vehicle 10 is further equipped with a VSC deactivation switch 88. The VSC deactivation switch 88 is a switch operated by the driver to limit VSC operation. Modes for limiting VSC operation include, for example, a VSC-off mode in which VSC is basically deactivated during normal driving, and a VSC sport driving mode in which VSC is basically deactivated during sport driving. For example, a deactivation operation signal Soff is supplied to the electronic control unit 90 each time the VSC deactivation switch 88 is operated. This allows the VSC mode to be switched between the VSC-off mode, the VSC sport driving mode, and the VSC-on mode in which VSC is activated, depending on the operation of the VSC deactivation switch 88. Sport driving is a type of vehicle driving in which the vehicle 10 skids when cornering, and is also referred to as drift driving. The term "basically" refers to, for example, except when activation is required for safety reasons.

[0029] The electronic control device 90 outputs various command signals to each device provided in the vehicle 10. The devices are, for example, the engine control device 50, the hydraulic control circuit 52, and the wheel brake device 54. The various command signals are, for example, an engine control command signal Se, an engagement hydraulic control command signal Scb, an LU hydraulic control command signal Slu, and a brake control command signal Sbra. The engine control command signal Se is a command signal for controlling the engine 12. The engagement hydraulic control command signal Scb is a command signal for controlling the engagement device CB and is the command hydraulic pressure of the engagement hydraulic pressure PRcb. The LU hydraulic control command signal Slu is a command signal for controlling the LU clutch 36 and is the command hydraulic pressure of the LU hydraulic pressure PRlu. The brake control command signal Sbra is a command signal for controlling the wheel braking torque Tb.

[0030] The electronic control unit 90 includes a driving control unit 92 and a brake control unit 94 to realize various controls in the vehicle 10 .

[0031] The driving control unit 92 includes an engine control unit 92 a that controls the engine 12 and a transmission control unit 92 b that controls the shifting of the automatic transmission 22 .

[0032] The engine control unit 92a calculates a drive demand made by the driver to the vehicle 10 by applying the accelerator opening θacc and the vehicle speed V to a drive demand map, which is determined in advance, for example, experimentally or by design, i.e., a predetermined drive demand map. The drive demand may be, for example, a required drive torque Tddem at the drive wheels 14. The engine control unit 92a outputs an engine control command signal Se to control the engine 12 so as to obtain a required engine torque Tedem for realizing the required drive torque Tddem, which is calculated in consideration of transmission loss, auxiliary load, gear ratio γat, etc. When the VSC is operating, for example, the engine control unit 92a outputs an engine control command signal Se to control the engine 12 so as to obtain a required engine torque Tedem for realizing the required drive torque Tddem required for each control.

[0033] The transmission control unit 92b determines whether the automatic transmission 22 should be shifted, for example, using a predetermined shift map, and outputs an engagement hydraulic control command signal Scb to the hydraulic control circuit 52 to execute shift control of the automatic transmission 22 based on the results of the shift determination.

[0034] The brake control unit 94 controls the wheel brake device 54. The brake control unit 94 outputs a brake control command signal Sbra for generating a wheel braking torque Tb corresponding to the brake operation amount Bra. When the VSC or automatic brake control is activated, the brake control unit 94 outputs the brake control command signal Sbra for generating the wheel braking torque Tb required for each control.

[0035] Incidentally, if the vehicle speed V or engine speed Ne drops to a low range during drifting in D range, the shift map may not determine whether the automatic transmission 22 should be downshifted, and a downshift may not be performed. In this case, during drifting, where the accelerator pedal is repeatedly operated on and off, the drive wheels 14 may grip due to a lack of drive torque Td caused by a decrease in engine speed Ne, which may result in poor vehicle posture during drifting. Furthermore, after turning, the vehicle accelerates from a state where the engine speed Ne has decreased, which may result in poor re-acceleration. When drifting in D range, it is desirable to maintain the low-speed gear GS to smoothly corner and ensure good acceleration response. The low-speed gear GS is the low gear GSlow, which has a relatively large gear ratio γat.

[0036] Therefore, when the electronic control unit 90 detects a decrease in vehicle speed V while drifting in D range, it downshifts the automatic transmission 22. The electronic control unit 90 prevents a decrease in driving performance by turning while maintaining the engine rotation speed Ne in a high range. In this case, it is not desirable to downshift when the VSC is activated while driving on a slippery road surface such as a snowy road. By limiting the activation of the VSC to a state in which it is restricted, the electronic control unit 90 can also be used for driving other than motorsports, for example. For this reason, the electronic control unit 90 further includes a sports driving determination unit 96 and a condition satisfaction determination unit 98.

[0037] The sports driving determination unit 96 determines whether sports driving, i.e., drift driving, is being performed. The sports driving determination unit 96 functions as a drift driving determination unit. The sports driving determination unit 96 determines whether drift driving is being performed based on whether the vehicle is in any one of an oversteer state, an understeer state, a countersteer state, and a vehicle counter state. The drift driving determined by the sports driving determination unit 96 is drift driving in a broad sense, including an oversteer state, an understeer state, a countersteer state, and a vehicle counter state. The countersteer state is a state in which the steering wheel is operated in a direction opposite to the left and right of the turning direction of the vehicle 10, and is a drift driving state in the narrow sense. The vehicle counter state is a state in which the vehicle 10 skids when returning from a countersteer state to a straight driving state. The sport driving determination unit 96 determines whether the vehicle is in an oversteer state, an understeer state, a countersteer state, or a vehicle countersteer state, based on, for example, the lateral acceleration Gy, the yaw rate Ryaw, the steering angle θsw, the steering direction Dsw, etc.

[0038] The condition satisfaction determination unit 98 determines whether or not the permission conditions Cp are satisfied. The permission conditions Cp are prerequisites for permitting a downshift of the automatic transmission 22 while drifting in the D range is being performed. The permission conditions Cp include the vehicle speed V being less than a predetermined vehicle speed Vf and the VSC operation being restricted.

[0039] The predetermined vehicle speed Vf is a lower limit value of a predetermined vehicle speed V at which an engine torque Te that realizes a driving torque Td required for drifting can be generated. The engine 12 has a torque band, which is, for example, a range of engine rotation speeds Ne at which the engine torque Te is likely to be generated. The predetermined vehicle speed Vf is a vehicle speed V corresponding to the lower limit value of the range of engine rotation speeds Ne in this torque band. The vehicle speed V being less than the predetermined vehicle speed Vf is synonymous with the transmission output rotation speed No being less than a predetermined output rotation speed Nof. The predetermined output rotation speed Nof is a predetermined threshold value corresponding to the predetermined vehicle speed Vf. The predetermined vehicle speed Vf and the predetermined output rotation speed Nof are also values ​​that prevent the engine rotation speed Ne from exceeding an allowable rotation speed after, for example, a downshift of the automatic transmission 22.

[0040] The state in which VSC operation is restricted is a state in which the VSC mode is set to VSC off mode or VSC sport driving mode by operating the VSC release switch 88.

[0041] The transmission control unit 92b determines whether the shift range Rsh of the automatic transmission 22 is in the D range. When the transmission control unit 92b determines that the shift range Rsh is in the D range, if the sport driving determination unit 96 determines that drift driving is being performed and the condition satisfaction determination unit 98 determines that the permission condition Cp is satisfied, the transmission control unit 92b executes a downshift of the automatic transmission 22. In this way, the traveling control unit 92 determines whether to downshift the automatic transmission 22 using the shift map, and also determines whether to downshift the automatic transmission 22 based on the engine rotation speed Ne (which is also synonymous with the vehicle speed V and transmission output rotation speed No).

[0042] The transmission control unit 92b downshifts the automatic transmission 22 while drifting, using a blipping downshift rather than a clutch-to-clutch shift. A blipping downshift is a downshift in which the transmission input rotation speed Ni is increased by engine torque Te toward the post-downshift synchronous rotation speed (= γata × No) using the disengagement side engagement device while the disengagement side engagement device is disengaged, and then the engagement side engagement device is engaged. "γata" is the gear ratio γat in the gear position GS after the downshift. A blipping downshift shortens the shift transition time compared to a clutch-to-clutch shift.

[0043] A blipping downshift may not be performed properly when the oil temperature THfld is low. Alternatively, a blipping downshift is a control that uses engine torque Te to increase the transmission input rotation speed Ni, which cannot be increased naturally when the disengaging engagement device is disengaged and the vehicle is in neutral. In other words, a blipping downshift is performed by increasing the engine torque Te, which is relatively small, regardless of the accelerator pedal stroke θacc. In other words, a blipping downshift may not be able to properly increase the transmission input rotation speed Ni toward the synchronous rotation speed after the downshift if the engine torque Te is originally large. For this reason, the permission condition Cp may further include at least one of the following: the oil temperature THfld is equal to or higher than the lower limit oil temperature THfldf, and the accelerator pedal stroke θacc is equal to or lower than the upper limit accelerator pedal stroke θaccf. The lower limit oil temperature THfldf is, for example, a predetermined threshold at which a blipping downshift is possible. The upper limit accelerator opening degree θaccf is a predetermined upper limit accelerator operation amount at which transient control of, for example, a blipping downshift becomes possible.

[0044] Considering drivability, a situation in which it is preferable to ensure acceleration responsiveness is, for example, a situation in which the drive mode MODEdr of the vehicle 10 is set to the sport mode by the mode selection switch 82. Therefore, the permission condition Cp may further include a condition that the drive mode MODEdr set for the vehicle 10 is the sport mode.

[0045] FIG. 2 is a flowchart explaining the main control operations of the electronic control unit 90, which are executed repeatedly, for example, to suppress unnecessary downshifts when performing drift driving and to facilitate ensuring the drive torque Td.

[0046] 2, first, in step S10 (hereinafter, the term "step" will be omitted) corresponding to the function of the transmission control unit 92b, it is determined whether the shift range Rsh is in the D range. If the determination in S10 is negative, the routine is terminated. If the determination in S10 is positive, it is determined in S20 corresponding to the function of the sport driving determination unit 96 whether drift driving is being performed. If the determination in S20 is positive, it is determined in S30 corresponding to the function of the condition satisfaction determination unit 98 whether the permission condition Cp is satisfied. If the determination in S30 is positive, a downshift of the automatic transmission 22 is performed in S40 corresponding to the function of the transmission control unit 92b. If the determination in S20 is negative, or if the determination in S30 is negative, a downshift of the automatic transmission 22 is not performed in S50 corresponding to the function of the transmission control unit 92b.

[0047] FIG. 3 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 2 is executed. FIG. 3 shows an example of a case where the vehicle is traveling in the VSC off mode or the VSC sport driving mode in the D range. In FIG. 3, time t1 indicates the time when a determination that the vehicle is drifting is initiated. When the vehicle speed V becomes lower than a predetermined vehicle speed Vf during drifting, the automatic transmission 22 is downshifted (see time t2). In the comparative example shown by the dashed line, a downshift is not executed during drifting, so the engine torque Te is kept in a low range (see time t2 onward), and the vehicle posture during drifting is not maintained properly (see the yaw rate Ryaw or the lateral acceleration Gy). Furthermore, the acceleration response after turning is poor. On the other hand, in the present embodiment shown by the solid line, the downshift maintains the engine torque Te in a high range (see time t2 onward), and the vehicle posture during drifting is maintained properly (see the yaw rate Ryaw or the lateral acceleration Gy). Furthermore, the acceleration response after turning is improved.

[0048] As described above, according to this embodiment, when the shift range Rsh is in the D range, if it is determined that drift driving is being performed and the permission condition Cp is satisfied, the automatic transmission 22 is downshifted. As a result, downshifts are performed during drift driving, the engine rotation speed Ne is maintained in a high range, and the drive torque Td is more likely to be ensured. Furthermore, since downshifts are performed only when the permission condition Cp is satisfied, downshifts are not performed when the VSC is activated, for example. In other words, by limiting VSC activation, unnecessary downshifts are not performed during slippage other than drift driving (equivalent to when the VSC is activated), making it easier to achieve compatibility with normal driving. Therefore, when drift driving is being performed, unnecessary downshifts can be suppressed while the drive torque Td is more likely to be ensured. During drift driving, the engine rotation speed Ne is maintained in a high range, making it easier to control the vehicle posture. Furthermore, acceleration performance upon exiting a corner is improved.

[0049] Furthermore, according to this embodiment, the predetermined vehicle speed Vf is the lower limit of the vehicle speed V that can generate the engine torque Te that realizes the drive torque Td required for drifting. This allows a downshift to be performed during drifting, keeping the engine rotation speed Ne in a high range and making it easier to ensure the drive torque Td.

[0050] Furthermore, according to this embodiment, the downshift of the automatic transmission 22 during drifting is a blipping downshift, which shortens the time required for the shift transition compared to a clutch-to-clutch shift, and quickly maintains the engine rotation speed Ne in a high range.

[0051] According to this embodiment, the permission condition Cp may further include at least one of the following: the oil temperature THfld is equal to or higher than the lower limit oil temperature THfldf; and the accelerator pedal stroke θacc is equal to or lower than the upper limit accelerator pedal stroke θaccf. This allows the automatic transmission 22 to appropriately perform a blipping downshift during drifting.

[0052] According to this embodiment, the permission conditions Cp may further include a requirement that the drive mode MODEdr set in the vehicle 10 be a sports mode. This improves acceleration response, thereby improving drivability.

[0053] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention can also be applied to other embodiments.

[0054] For example, in the above-described embodiment, the engine 12 is used as an example of the power source, but the present invention is not limited to this. For example, an electric motor may be used as the power source in addition to or instead of the engine 12.

[0055] Furthermore, in the above-described embodiment, the downshift of the automatic transmission 22 during drifting does not have to be a blipping downshift, but may be a clutch-to-clutch downshift. Even in this case, a certain effect of the present invention can be obtained.

[0056] In the above-described embodiment, a planetary gear type stepped transmission is exemplified as the automatic transmission 22, but the present invention is not limited to this. For example, excluding the control related to the blipping downshift, the automatic transmission 22 may be a synchronous mesh type parallel two-shaft automatic transmission including a known DCT (Dual Clutch Transmission), a known continuously variable transmission such as a belt type, or a known electric continuously variable transmission. In the case of a continuously variable transmission, for example, a stepped gear may be formed.

[0057] Furthermore, in the above-described embodiment, the drive mode MODEdr may include a drift mode, which is a predetermined drive mode for driving the vehicle 10 in a state that makes it easy for the vehicle 10 to skid when turning, for example. This drift mode is a drive mode suitable for drift driving, which is driving that makes the vehicle 10 skid when turning. The permission condition Cp may further include that the drive mode MODEdr set for the vehicle 10 is the drift mode. This allows the vehicle posture to be well maintained during drift driving, thereby improving drivability.

[0058] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0059] 10: Vehicle 12: Engine (power source) 14: Drive wheels 22: Automatic transmission 90: Electronic control unit (control unit) 92b: Transmission control unit 96: Sports driving determination unit 98: Condition satisfaction determination unit CB: Engagement device FLD: Oil (hydraulic oil)

Claims

1. A control device for a vehicle including a power source and an automatic transmission provided in a power transmission path between the power source and drive wheels, a sport driving determination unit that determines whether or not the vehicle is currently in sport driving mode, which causes the vehicle to skid when turning; a condition satisfaction determination unit that determines whether or not a permission condition is satisfied, that is, the vehicle speed is less than a predetermined vehicle speed and the operation of the sideslip suppression control is restricted; a transmission control unit that downshifts the automatic transmission when it is determined that the sport driving is being performed and the permission condition is satisfied, while the shift position of the automatic transmission is a forward driving position that enables forward driving by executing automatic shift control; A vehicle control device comprising:

2. 2. The vehicle control device according to claim 1, wherein the predetermined vehicle speed is a lower limit value of the vehicle speed that is set in advance so that the torque of the power source can be generated to realize the drive torque required for executing the sport driving.

3. the automatic transmission is a stepped transmission in which one of a plurality of gear stages is formed by engagement of one of a plurality of engagement devices, 3. The vehicle control device according to claim 1, wherein the downshift is a blipping downshift in which the engagement device on the engagement side is engaged after the input rotation speed of the stepped transmission is increased toward the synchronous rotation speed after the downshift using the torque of the power source while the engagement device on the release side is disengaged.

4. 4. The vehicle control device according to claim 3, wherein the permission conditions further include at least one of: a temperature of hydraulic oil used in gear shifting operations of the automatic transmission being equal to or higher than a predetermined lower limit oil temperature at which the blipping downshift can be performed; and an accelerator operation amount being equal to or lower than a predetermined upper limit accelerator operation amount at which transient control of the blipping downshift can be performed.

5. 3. The vehicle control device according to claim 1, wherein the permission conditions further include that the drive mode set for the vehicle is a sports mode in which the vehicle is driven in a state in which power performance is prioritized over energy efficiency.

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