JP2022110976A - Vehicle control device - Google Patents

Abstract

To suppress delay in progress of down-shift while suppressing deterioration in energy efficiency, when determining the down-shift during regenerative control.SOLUTION: When down-shift is determined during execution of regenerative control, the down-shift can be started so that a progress stage of the down-shift is set to a preparation stage, which can shorten delay time in the down-shift more in comparison with a case where starting of the downs-shift can be delayed until an absolute value of a torque difference between a target value and an actual value of regenerative braking torque is equal to a predetermined torque difference or lower. Further, even when the preparation stage is completed, the completed preparation stage is maintained until the absolute value of the torque difference is equal to the predetermined torque difference or lower and a torque phase is started and the down-shift is progressed after the absolute value of the torque difference falls below the predetermined torque difference, which enables the actual value of the regenerative braking torque to get close to the target value, in the preparation stage in which shift-shock is suppressed from occurring even if the actual value of the regenerative braking torque is increased.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle having an automatic transmission downstream of a driving force source including an electric motor.

The electric motor constitutes a part of the power transmission path between the electric motor and the drive wheels, and engagement of any one of the plurality of engagement devices forms any one of the plurality of gear stages. Control systems for vehicles with automatic transmissions are well known. For example, a vehicle control device described in Patent Document 1 is one of them. In Patent Document 1, when a downshift of an automatic transmission is determined during regenerative control of an electric motor in response to a braking operation by a driver, the change rate of regenerative torque is reduced in order to suppress shift shock. It is disclosed to start executing a downshift after the

Japanese Patent Application Laid-Open No. 2019-1181

By the way, in the technique disclosed in Patent Document 1, the start of the downshift of the automatic transmission is delayed while the regenerative torque is increasing, and it is possible to increase the regenerative energy. is delayed, and there is a possibility that the shift to the optimum gear will be delayed. On the other hand, if priority is given to advancing the downshift, when the downshift is executed during regenerative control of the electric motor, the regenerative torque is increased during the execution of the downshift in order to suppress shift shock. It is conceivable to prohibit or suppress However, prohibiting or suppressing an increase in regenerative torque may reduce energy efficiency.

The present invention has been made against the background of the above circumstances, and its object is to suppress a decrease in energy efficiency when downshifting of an automatic transmission is determined during regeneration control of an electric motor. To provide a vehicle control device capable of suppressing a delay in the progress of downshifting.

The gist of the first invention is that: (a) the electric motor constitutes a part of the power transmission path between the electric motor and the drive wheels, and is engaged by any one of a plurality of engagement devices; and an automatic transmission in which any one of a plurality of gear stages is formed, wherein: and (c) a shift control unit for shifting the automatic transmission by switching to the state and switching the engagement side engagement device of the engagement devices to the engaged state; an electric motor control unit that performs regenerative control of the electric motor and controls an actual value of the regenerative braking torque, which is braking torque, so as to achieve a target value; When a downshift of the automatic transmission is determined while regenerative control is being performed, the disengagement-side engagement device may be in charge of the input torque to the automatic transmission during the progressing stage of the downshift. The downshift is started so as to make the engine stand by with a possible torque capacity and to prepare for a preparation stage in which the engagement side engagement device is put in a packing completion state in which the pack clearance is narrowed, and the preparation stage is completed. Also, the absolute value of the torque difference between the target value and the actual value of the regenerative braking torque determines that the actual value has approached the target value to the extent that a decrease in energy efficiency can be suppressed. The advance stage is maintained in a state in which the preparation stage is completed until the difference becomes less than or equal to the difference, and the torque phase, which is the advance stage subsequent to the preparation stage, is maintained after the absolute value of the torque difference becomes equal to or less than the predetermined torque difference. is started to advance the downshift.

According to the first aspect of the invention, when it is determined that the automatic transmission is to downshift while the regenerative control of the electric motor is being performed, the downshift is started so that the progressing stage of the downshift is set to the preparatory stage. Therefore, the downshift delay time can be shortened compared to delaying the start of the downshift until the absolute value of the torque difference between the target value and the actual value of the regenerative braking torque becomes equal to or less than the predetermined torque difference. . Further, even if the preparatory stage is completed, the advancing stage is maintained in the state where the preparatory stage is completed until the absolute value of the torque difference becomes equal to or less than the predetermined torque difference, and the absolute value of the torque difference is maintained in the predetermined state. Since the torque phase is started after the torque difference becomes equal to or less than the torque difference, and the downshift is proceeded, the actual value of the regenerative braking torque is reduced in the preparatory stage in which the shift shock is unlikely to occur even if the actual value of the regenerative braking torque is increased. is brought closer to the target value. Therefore, when it is determined to downshift the automatic transmission during regeneration control of the electric motor, it is possible to suppress a delay in progress of the downshift while suppressing a decrease in energy efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining a schematic configuration of a vehicle to which the present invention is applied, and is a diagram for explaining main parts of a control system and control functions for various controls in the vehicle; 4 is a flowchart for explaining the main part of the control operation of the electronic control unit, suppressing a delay in the progress of the downshift while suppressing a decrease in energy efficiency when a downshift of the automatic transmission is determined during regeneration control of the electric motor. 2 is a flow chart for explaining the control operation for 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.

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

FIG. 1 is a diagram for explaining a schematic configuration of a vehicle 10 to which the present invention is applied, and is a diagram for explaining control functions and main parts of a control system for various controls in the vehicle 10. As shown in FIG. In FIG. 1, a vehicle 10 is a hybrid vehicle including an engine 12 and an electric motor MG, which are driving force sources for running. The vehicle 10 also includes drive wheels 14 and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14 .

The engine 12 is a known internal combustion engine such as a gasoline engine or a diesel engine. An engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, and the like provided in the vehicle 10 is controlled by an electronic control device 90, which will be described later, to control the engine 12. The engine torque Te, which is the output torque of the engine 12, is controlled by the engine 12. is controlled.

The electric motor MG is a rotating electric machine having a function as a motor that generates mechanical power from electric power and a function as a generator that generates power from mechanical power, and is a so-called motor generator. Electric motor MG is connected to a battery 54 provided in vehicle 10 via an inverter 52 provided in vehicle 10 . The battery 54 is a power storage device that transfers electric power to and from the electric motor MG. In the electric motor MG, the MG torque Tm, which is the output torque of the electric motor MG, is controlled by controlling the inverter 52 by the electronic control unit 90, which will be described later. For example, when the rotation direction of the electric motor MG is the same rotation direction as the engine 12 is running, the MG torque Tm is a power running torque when the positive torque is on the acceleration side, and is a regenerative torque when the negative torque is on the deceleration side. be. Electric power is also synonymous with electrical energy when not specifically distinguished. The power is also synonymous with torque and force unless otherwise specified.

The power transmission device 16 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, etc. in a case 18, which is a non-rotating member attached to the vehicle body. K0 clutch 20 is a clutch provided between engine 12 and electric motor MG in a power transmission path between engine 12 and driving wheels 14 . Torque converter 22 is connected to engine 12 via K0 clutch 20 . Automatic transmission 24 is connected to torque converter 22 and is interposed in a power transmission path between torque converter 22 and drive wheels 14 . The torque converter 22 and the automatic transmission 24 each form part of a power transmission path between the drive power source (the engine 12 and the electric motor MG) and the drive wheels 14 . The power transmission device 16 includes a propeller shaft 28 connected to a transmission output shaft 26 which is an output rotating member of an automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, and a gear 1 connected to the differential gear 30. A pair of drive shafts 32 and the like are provided. The power transmission device 16 also includes an engine connection shaft 34 that connects the engine 12 and the K0 clutch 20, an electric motor connection shaft 36 that connects the K0 clutch 20 and the torque converter 22, and the like.

The electric motor MG is connected to the electric motor connecting shaft 36 within the case 18 so as to be able to transmit power. In other words, the electric motor MG is connected to the power transmission path between the K0 clutch 20 and the torque converter 22 so that power can be transmitted. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 without the K0 clutch 20 so that power can be transmitted.

The torque converter 22 includes a pump impeller 22 a connected to an electric motor connecting shaft 36 and a turbine impeller 22 b connected to a transmission input shaft 38 which is an input rotating member of the automatic transmission 24 . Torque converter 22 is a hydrodynamic transmission device that transmits driving force from each of the driving force sources (engine 12, electric motor MG) from electric motor coupling shaft 36 to transmission input shaft 38 via fluid. The torque converter 22 includes an LU clutch 40 as a direct clutch that connects the pump impeller 22a and the turbine impeller 22b, that is, connects the electric motor connecting shaft 36 and the transmission input shaft 38. The LU clutch 40 is a known lockup clutch.

The automatic transmission 24 is a known planetary gear type automatic transmission including, for example, one or a plurality of sets of planetary gears (not shown) and a plurality of engagement devices CB. The engagement device CB is, for example, a known hydraulic friction engagement device. Each engagement device CB changes its torque capacity CB torque Tcb by CB hydraulic pressure PRcb which is regulated hydraulic pressure supplied from the hydraulic control circuit 56, so that the engagement device CB is in an engaged state or a disengaged state. is switched between operating states or control states.

The automatic transmission 24 has a plurality of gear ratios (also referred to as gear ratios) γat (=AT input rotation speed Ni/AT output rotation speed No) that differ by engagement of any one of the engagement devices CB. is a stepped transmission in which any one of gear stages (also referred to as gear stages) is formed. The automatic transmission 24 is controlled by an electronic control unit 90, which will be described later, according to the driver's accelerator operation, the vehicle speed V, etc. By switching the control state of the predetermined engagement device, the gear stage to be formed is switched. In other words, in the shift control of the automatic transmission 24, the shift is executed by, for example, re-holding a predetermined engagement device, that is, the shift is performed by disengaging the release-side engagement device and engaging the engagement-side engagement device. A so-called clutch-to-clutch shift is executed. The disengagement side engagement device is an engagement device that is in the engaged state before the shift of the automatic transmission 24 among the predetermined engagement devices, and is released from the engaged state during the transition of the shift of the automatic transmission 24. It is an engagement device that is controlled towards a released state. The engagement side engagement device is an engagement device that is in a disengaged state before the shift of the automatic transmission 24 among predetermined engagement devices, and is disengaged from the disengaged state during a shift transition of the automatic transmission 24. It is an engagement device that is controlled towards the engaged state. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38 and the input rotation speed of the automatic transmission 24 . The AT input rotation speed Ni has the same value as the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22 . The AT input rotation speed Ni can be represented by the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26 and the output rotation speed of the automatic transmission 24 .

The K0 clutch 20 is a hydraulic friction engagement device composed of, for example, a multi-plate or single-plate clutch. The K0 clutch 20 changes the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, by the K0 hydraulic pressure PRk0, which is the regulated hydraulic pressure supplied from the hydraulic control circuit 56, so that the engaged state and the disengaged state are changed. Control state is switched.

In the vehicle 10, when the K0 clutch 20 is engaged, the engine 12 and the torque converter 22 are connected so as to be able to transmit power. On the other hand, when the K0 clutch 20 is released, 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 connects and disconnects the engine 12 with the electric motor MG.

In the power transmission device 16, when the K0 clutch 20 is engaged, the power output from the engine 12 is transmitted from the engine connection shaft 34 to the K0 clutch 20, the electric motor connection shaft 36, the torque converter 22, the automatic transmission 24, The power is transmitted to the drive wheels 14 through the propeller shaft 28, the differential gear 30, the drive shaft 32, and the like. The power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. regardless of the control state of the K0 clutch 20. The power is transmitted to the driving wheels 14 through successively.

The vehicle 10 includes a mechanical oil pump MOP 58, an electric oil pump EOP 60, a pump motor 62, and the like. The MOP 58 is connected to the pump impeller 22a, and is driven to rotate by a driving force source (engine 12, electric motor MG) to discharge hydraulic oil OIL used in the power transmission device 16. As shown in FIG. The pump motor 62 is a motor dedicated to the EOP 60 for rotating the EOP 60 . The EOP 60 is rotationally driven by the pump motor 62 to discharge hydraulic oil OIL. Hydraulic oil OIL discharged from the MOP 58 and the EOP 60 is supplied to the hydraulic control circuit 56 . The hydraulic control circuit 56 supplies the CB hydraulic pressure PRcb, the K0 hydraulic pressure PRk0, etc., each of which is adjusted based on the hydraulic oil OIL discharged from the MOP 58 and/or the EOP 60 .

The vehicle 10 has a wheel brake device 64 . The wheel brake device 64 is a brake device that applies a wheel braking torque TBw, which is braking torque TB due to a wheel brake, to the wheels. The wheel brake device 64 supplies brake hydraulic pressure to the wheel cylinders provided in the wheel brakes in response to, for example, the driver's depression of a brake pedal. In the wheel brake device 64, normally, the master cylinder hydraulic pressure generated from the brake master cylinder and corresponding to the brake operation amount Bra is supplied to the wheel cylinders as the brake hydraulic pressure. On the other hand, in the wheel brake device 64, for example, when the ABS function is activated, during side slip suppression control, during vehicle speed control, during automatic driving control, during automatic braking function activation, during regeneration control, etc., the wheel braking torque TBw is generated. Therefore, the brake hydraulic pressure corresponding to the wheel braking torque TBw required for each control is supplied to the wheel cylinders. The wheels are drive wheels 14 and driven wheels (not shown). The brake operation amount Bra is a signal representing the magnitude of the brake pedal depression operation by the driver, that is, the magnitude of the brake operation, corresponding to the force applied to the brake pedal.

The vehicle 10 further includes an electronic control unit 90 that includes a control unit for the vehicle 10 . The electronic control unit 90 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, and an input/output interface. Various controls of the vehicle 10 are executed by performing signal processing. The electronic control unit 90 includes computers for engine control, electric motor control, hydraulic control, etc., as required.

The electronic control unit 90 includes various sensors provided in the vehicle 10 (for example, the engine rotation speed sensor 70, the turbine rotation speed sensor 72, the output rotation speed sensor 74, the MG rotation speed sensor 76, the accelerator opening sensor 78, the throttle valve Various signals based on values detected by an opening sensor 80, a brake pedal sensor 82, a battery sensor 84, an oil temperature sensor 86, etc. A certain turbine rotation speed Nt, an AT output rotation speed No corresponding to the vehicle speed V, an MG rotation speed Nm that is the rotation speed of the electric motor MG, and an accelerator opening that is a driver's accelerator operation amount that indicates the magnitude of the driver's acceleration operation. θacc, throttle valve opening θth, which is the opening of the electronic throttle valve, brake-on signal Bon, which is a signal indicating that the brake pedal for operating the wheel brake is being operated by the driver, brake operation amount Bra, battery 54, the battery temperature THbat, the battery charging/discharging current Ibat, the battery voltage Vbat, the working oil temperature THoil which is the temperature of the working oil OIL in the hydraulic control circuit 56, etc.) are supplied.

From the electronic control device 90, various command signals (for example, the engine 12 is Engine control command signal Se for controlling, MG control command signal Sm for controlling electric motor MG, CB hydraulic control command signal Scb for controlling engagement device CB, K0 hydraulic control for controlling K0 clutch 20 command signal Sk0, LU hydraulic control command signal Slu for controlling the LU clutch 40, EOP control command signal Seop for controlling the EOP 60, brake control command signal Sbra for controlling the wheel braking torque TBw, etc.) are respectively output.

The electronic control unit 90 includes hybrid control means, a hybrid control section 92 , shift control means, a shift control section 94 , and braking control means, a braking control section 96 , in order to implement various controls in the vehicle 10 .

The hybrid control unit 92 functions as engine control means for controlling the operation of the engine 12, that is, an engine control unit 92a, and functions as an electric motor control unit, that is, an electric motor control unit 92b for controlling the operation of the electric motor MG via the inverter 52. , and the hybrid drive control by the engine 12 and the electric motor MG is executed by these control functions.

The hybrid control unit 92 calculates the amount of driving demand for the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand amount map. The required drive amount map is a relationship that is experimentally or design-experimentally obtained and stored, that is, a predetermined relationship. The required drive amount is, for example, the required drive torque Trdem at the drive wheels 14 . The required driving torque Trdem [Nm] is, in other words, the required driving power Prdem [W] at the vehicle speed V at that time. As the required driving amount, the required driving force Frdem [N] at the driving wheels 14, the required AT output torque at the transmission output shaft 26, and the like can be used. In the calculation of the drive demand amount, the AT output rotation speed No or the like may be used instead of the vehicle speed V. FIG.

The hybrid control unit 92 considers the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 24, the chargeable power Win and the dischargeable power Wout of the battery 54, and the like so as to realize the required drive power Prdem. It 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. The engine control command signal Se is, for example, a command value of the engine power Pe, which is the power of the engine 12 that outputs the engine torque Te at the engine rotation speed Ne at that time. The MG control command signal Sm is, for example, a command value for the power consumption Wm of the electric motor MG that outputs the MG torque Tm at the MG rotational speed Nm at that time.

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

The hybrid control unit 92 sets the driving mode to the motor driving (=EV driving) mode when the required drive torque Trdem can be covered only by the output of the electric motor MG. In the EV traveling mode, the hybrid control unit 92 performs EV traveling in which driving force is output only from the electric motor MG of the driving force sources (the engine 12 and the electric motor MG) when the K0 clutch 20 is released. On the other hand, when the required drive torque Trdem cannot be met without using at least the output of the engine 12, the hybrid control unit 92 sets the running mode to the engine running mode, that is, the hybrid running (=HV running) mode. In the HV running mode, the hybrid control unit 92 outputs the driving force from at least the engine 12 of the driving force sources (the engine 12 and the electric motor MG) in the engaged state of the K0 clutch 20 to run the engine running, that is, the HV running. I do. On the other hand, even when the required drive torque Trdem can be covered only by the output of the electric motor MG, the hybrid control unit 92 controls the state of charge value SOC of the battery 54 to be less than the predetermined engine start threshold value or the engine 12 or the like. When it is necessary to warm up the engine, the HV running mode is established. The engine start threshold is a predetermined threshold for determining the state of charge value SOC at which it is necessary to forcibly start the engine 12 and charge the battery 54 .

The shift control unit 94 determines the shift of the automatic transmission 24 using, for example, a shift map having a predetermined relationship, and outputs a CB hydraulic control command signal for executing shift control of the automatic transmission 24 as necessary. Scb is output to the hydraulic control circuit 56 . In the shift control of the automatic transmission 24, the shift control unit 94 shifts the automatic transmission 24 by, for example, switching the release-side engagement device to the released state and switching the engagement-side engagement device to the engaged state. conduct. The shift map is a predetermined relationship having a shift line for judging the shift of the automatic transmission 24 on two-dimensional coordinates having, for example, the vehicle speed V and the required drive torque Trdem as variables. In the shift map, the AT output rotational speed No may be used instead of the vehicle speed V, and the required driving force Frdem, the accelerator opening θacc, the throttle valve opening θth, etc. may be used instead of the required driving torque Trdem. can be

Progressive stages, or phases, of the shift of the automatic transmission 24 will be described by exemplifying a downshift during deceleration. When the shift control unit 94 determines that the automatic transmission 24 is to downshift, the shift control unit 94 waits for the downshift phase with a torque capacity that allows the disengagement side engagement device to take charge of the input torque Tin to the automatic transmission 24. At the same time, the CB hydraulic control command signal Scb is output to the hydraulic control circuit 56 to start the downshift, in order to enter a preparatory stage, that is, a preparatory phase, in which the engaging device on the engaging side is placed in a packing completion state in which the pack clearance is reduced. . The packing completion state of the engagement device CB is a state in which the engagement device CB starts to have a torque capacity if the CB oil pressure PRcb is increased from the packing completion state. The shift control unit 94 determines whether or not the preparation phase has been completed based on whether or not the predetermined preparation time TMpk has elapsed since the start of the preparation phase. The predetermined preparation time TMpk is, for example, a predetermined time during which the engagement device on the engagement side is in a packing completion state. When the shift control unit 94 determines that the preparation phase is completed, the shift control unit 94 outputs the CB oil pressure control command signal Scb for gradually decreasing the torque capacity of the disengagement side engagement device and gradually increasing the torque capacity of the engagement side engagement device. to the hydraulic control circuit 56 to initiate the torque phase. In the case of downshifting, this torque phase is a phase in which the torque capacity of the engagement side engagement device is brought out and the output torque of the automatic transmission 24 changes. When the turbine rotation speed Nt (=AT input rotation speed Ni) is increased toward the post-downshift synchronous rotation speed (=No x γat after downshift) during the downshift transition, the downshift phase becomes the torque phase. to the inertia phase. In the inertia phase, the shift control unit 94 outputs to the hydraulic control circuit 56 a CB hydraulic control command signal Scb for changing the turbine rotation speed Nt at a predetermined rising gradient in consideration of shift time and shift shock. do. The shift control unit 94 determines whether or not the downshift has ended based on whether or not the turbine rotation speed Nt matches the synchronous rotation speed after the downshift. When the shift control unit 94 determines that the downshift is completed, it sets the CB oil pressure PRcb of the disengagement side engagement device to zero and sets the CB oil pressure PRcb of the engagement side engagement device to zero. A CB hydraulic pressure control command signal Scb for maintaining the CB hydraulic pressure PRcb in the fully engaged state is output to the hydraulic control circuit 56 to complete a series of shift control related to the downshift.

The braking control unit 96 determines the required braking torque TBdem based on, for example, the vehicle speed V, the slope of the downhill road, and the brake operation by the driver for activating the wheel brakes (for example, the brake operation amount Bra and the increasing speed of the brake operation amount Bra). set. The braking control unit 96 generates the braking torque TB of the vehicle 10 so as to obtain the required braking torque TBdem during deceleration of the vehicle 10 . The side where the braking torque TB (<0) is small is the side where the absolute value of the braking torque TB is large. For convenience, increasing the absolute value of the braking torque TB is expressed as increasing the braking torque TB.

The required braking torque TBdem is basically a required braking torque for the wheel braking torque TBw by the wheel brake device 64, and is realized by the wheel braking torque TBw. It is preferentially realized by the torque TBr. That is, the braking torque TB that realizes the required braking torque TBdem is generated by, for example, the regenerative braking torque TBr and the wheel braking torque TBw. The regenerative braking torque TBr is the braking torque TB obtained by regenerative braking of the electric motor MG. Regeneration of the electric motor MG is control for rotating the electric motor MG by the driven torque input from the drive wheels 14 to operate it as a generator, and charging the battery 54 with electric power generated by the electric motor MG.

The braking control unit 96 outputs to the electric motor control unit 92b a command to perform regenerative control by the electric motor MG so as to obtain a target regenerative braking torque TBrt, which is a target value of the regenerative braking torque TBr.

The electric motor control unit 92b outputs an MG control command signal Sm for controlling the actual regenerative braking torque TBrr, which is the actual value of the regenerative braking torque TBr, so as to achieve the target regenerative braking torque TBrt, thereby performing regenerative control of the electric motor MG. I do. When the regenerative braking torque TBr can cover all of the requested braking torque TBdem, the requested braking torque TBdem is set as the target regenerative braking torque TBrt. Since the absolute value of the required braking torque TBdem is greater than the absolute value of the upper limit of the regenerative braking torque TBr, if only part of the required braking torque TBdem can be covered by the regenerative braking torque TBr, the upper limit of the regenerative braking torque TBr The value is set as the target regenerative braking torque TBrt.

A brake control command signal Sbra for obtaining the wheel braking torque TBw required to realize the requested braking torque TBdem of the requested braking torque TBdem that could not be realized by the actual regenerative braking torque TBrr. is output to the wheel brake device 64 . The requested braking torque TBdem of the requested braking torque TBdem that could not be realized with the actual regenerative braking torque TBrr is, for example, the requested braking torque that could not be realized with the upper limit value of the regenerative braking torque TBr out of the requested braking torque TBdem. Since the absolute value of the rate of increase of TBdem and the required braking torque TBdem is greater than the absolute value of the rate of increase of the actual regenerative braking torque TBrr, the actual regenerative braking torque TBrr cannot follow the change of the required braking torque TBdem. torque TBdem and the like.

By the way, it may be determined that the automatic transmission 24 should downshift while the regenerative control of the electric motor MG is being executed. In this case, if the increase in the actual regenerative braking torque TBrr, that is, the increase in the regenerative torque of the electric motor MG that becomes the input torque Tin to the automatic transmission 24 and the downshift of the automatic transmission 24 overlap, the shift shock may increase. have a nature. In order to suppress the shift shock described above, if priority is given to increasing the regenerative energy and the start of the determined downshift of the automatic transmission 24 is delayed while the actual regenerative braking torque TBrr is increasing, then the optimum gear position is obtained. migration may be delayed. Alternatively, in order to suppress the shift shock described above, if priority is given to advancing the downshift of the automatic transmission 24 and prohibiting or suppressing an increase in the actual regenerative braking torque TBrr during execution of the downshift, the energy efficiency will be improved. It may go down.

Therefore, if the shift control unit 94 determines that the automatic transmission 24 should downshift while the regenerative control of the electric motor MG is being performed, the shift control unit 94 performs the downshift so that the downshift phase becomes the preparation phase. Start. Furthermore, even after the preparation phase is completed, the shift control unit 94 maintains the absolute value of the residual regenerative braking torque ΔTBr (=TBrt−TBrr), which is the torque difference between the target regenerative braking torque TBrt and the actual regenerative braking torque TBrr. The downshift phase is maintained in the state where the preparation phase is completed until the torque difference ΔTBrf or less. Start phase to progress downshift. The predetermined torque difference ΔTBrf is a predetermined threshold value for determining that the actual regenerative braking torque TBrr has approached the target regenerative braking torque TBrt to such an extent that a decrease in energy efficiency can be suppressed, for example.

Further, the electric motor control section 92b suppresses or prohibits an increase in the actual regenerative braking torque TBrr from the start of the torque phase during the downshift transition of the automatic transmission 24 to the end of the downshift. When the downshift of the automatic transmission 24 is completed, the electric motor control unit 92b increases the actual regenerative braking torque TBrr so that the actual regenerative braking torque TBrr becomes the target regenerative braking torque TBrt. The rate of increase when the actual regenerative braking torque TBrr is increased so as to make the actual regenerative braking torque TBrr equal to the target regenerative braking torque TBrt, including the beginning of regenerative control, can be set, for example, in advance at which changes in the actual regenerative braking torque TBrr are allowed. It is a defined upper limit. The rate of increase when suppressing the increase in the actual regenerative braking torque TBrr is a value smaller than the absolute value of this upper limit value, and is a predetermined value for suppressing shift shock, for example.

Specifically, the electric motor control unit 92b determines whether or not regeneration control of the electric motor MG is being executed. The electric motor control unit 92b determines whether or not the absolute value of the residual regenerative braking torque ΔTBr is equal to or less than a predetermined torque difference ΔTBrf during execution of regenerative control of the electric motor MG.

When the electric motor control unit 92b determines that regenerative control of the electric motor MG is being executed, if the shift control unit 94 determines that the automatic transmission 24 is to downshift, the shift control unit 94 shifts the downshift phase to the preparation phase. Start the downshift as follows.

Even when the transmission control unit 94 determines that the preparation phase is completed after the downshift of the automatic transmission 24 is started, the electric motor control unit 92b determines that the absolute value of the residual regenerative braking torque ΔTBr is not equal to or less than the predetermined torque difference ΔTBrf. In this case, the downshift phase is not changed to the torque phase, and the state in which the preparation phase is completed is maintained. When the transmission control unit 94 determines that the preparation phase is completed after the downshift of the automatic transmission 24 is started, the electric motor control unit 92b determines that the absolute value of the residual regenerative braking torque ΔTBr is equal to or less than the predetermined torque difference ΔTBrf. If so, start the torque phase.

The electric motor control unit 92b causes the transmission control unit 94 to terminate the downshift when the transmission control unit 94 starts the torque phase during the downshift transition of the automatic transmission 24 during execution of the regenerative control of the electric motor MG. An increase in the actual regenerative braking torque TBrr is suppressed or prohibited until it is determined that When the shift control unit 94 determines that the downshift has ended, the electric motor control unit 92b increases the actual regenerative braking torque TBrr so that the actual regenerative braking torque TBrr becomes the target regenerative braking torque TBrt.

FIG. 2 is a flowchart for explaining the essential part of the control operation of the electronic control unit 90. When it is determined that the automatic transmission 24 should downshift during regeneration control of the electric motor MG, the downshift is suppressed while suppressing a decrease in energy efficiency. 4 is a flowchart for explaining a control operation for suppressing a delay in progress of a shift, which is repeatedly executed, for example; 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.

In FIG. 2, first, in step (hereinafter, step is omitted) S10 corresponding to the function of the electric motor control section 92b, it is determined whether or not regenerative control of the electric motor MG is being executed. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is affirmative, in S20 corresponding to the function of the shift control section 94, it is determined whether or not downshifting of the automatic transmission 24 has been determined. If the determination in S20 is negative, this routine is terminated. If the determination in S20 is affirmative, in S30 corresponding to the function of the shift control unit 94, the determined downshift phase is set as the preparation phase, and the downshift is started. Next, in S40 corresponding to the function of the shift control section 94, it is determined whether or not the preparation phase has been completed. If the determination in S40 is negative, S40 is repeatedly executed. If the determination in S40 is affirmative, in S50 corresponding to the function of the motor control section 92b, it is determined whether or not the absolute value of the residual regenerative braking torque ΔTBr is equal to or less than a predetermined torque difference ΔTBrf. If the determination in S50 is negative, in S60 corresponding to the function of the shift control unit 94, the downshift phase is maintained with the preparation phase completed. After S60, S50 is executed. If the determination in S50 is affirmative, in S70 corresponding to the function of the shift control section 94, the torque phase is started. Next, in S80 corresponding to the function of the electric motor control section 92b, the increase in the actual regenerative braking torque TBrr is suppressed or prohibited. Next, in S90 corresponding to the function of the shift control section 94, it is determined whether or not the downshift has been completed. If the determination in S90 is negative, the process returns to S80. When the determination in S90 is affirmative, in S100 corresponding to the function of the electric motor control section 92b, the actual regenerative braking torque TBrr is increased so that the actual regenerative braking torque TBrr becomes the target regenerative braking torque TBrt.

FIG. 3 is a diagram showing an example of a case where downshifting of the automatic transmission 24 is determined during execution of regenerative control of the electric motor MG. In FIG. 3, time t1 indicates the time at which the cooperative brake regenerative control is started to realize the required braking torque TBdem by the regenerative braking torque TBr and the wheel braking torque TBw. In this embodiment, the required braking torque TBdem is set as the target regenerative braking torque TBrt because the required braking torque TBdem can be entirely covered by the regenerative braking torque TBr. However, since the absolute value of the rate of increase of the requested braking torque TBdem is greater than the absolute value of the rate of increase of the actual regenerative braking torque TBrr (see rate A), the actual regenerative braking torque TBrr of the requested braking torque TBdem is equal to the requested braking torque. The wheel braking torque TBw compensates for the inability to follow the change in TBdem. "Rate A" is, for example, a predetermined upper limit value of the increase rate of the actual regenerative braking torque TBrr. When it is determined that the automatic transmission 24 should downshift during execution of the brake cooperative regeneration control, the downshift is started so that the downshift phase becomes the preparation phase (see time t2). In the comparative example indicated by the dashed line, the torque phase starts when the preparation phase is completed (see time t3), the actual regenerative braking torque TBrr is prohibited from increasing from the start of the torque phase until the downshift end determination time, and the actual regenerative braking torque TBrr is prohibited from increasing. The rate of increase of the regenerative braking torque TBrr is set to zero (see time t3-t7). On the other hand, in the present embodiment indicated by the solid line, even after the preparation phase is completed, the state in which the preparation phase is completed is maintained until the absolute value of the residual regenerative braking torque ΔTBr becomes equal to or less than the predetermined torque difference ΔTBrf (time t2). −t4), the torque phase starts after the absolute value of the residual regenerative braking torque ΔTBr becomes equal to or less than the predetermined torque difference ΔTBrf (see t4), and actual regeneration is performed from the start of the torque phase to the downshift end determination time. The increase in the braking torque TBrr is suppressed (see time t4-t8). "Rate B" is a value smaller than the absolute value of "Rate A", and is an increase rate of the actual regenerative braking torque TBrr for suppressing a predetermined shift shock, for example. Here, as shown by the solid line, after the inertia phase starts (see time t5), for example, the differential rotation speed between the turbine rotation speed Nt and the synchronous rotation speed before downshift (=No x γat before downshift) After the start of the inertia phase is actually determined based on the above, the rate of increase of the actual regenerative braking torque TBrr may be switched to zero (see rate C) (see time t6-t8). Alternatively, as in the present embodiment indicated by the chain double-dashed line, the increase in the actual regenerative braking torque TBrr is prohibited from the start of the torque phase to the end of downshift determination, and the increase rate of the actual regenerative braking torque TBrr becomes zero. (see time t4-t8). After determining the end of the downshift, the indicated pressure for the disengagement side engagement device is set to zero and the indicated pressure for the engagement side engagement device is set to a value that maintains the fully engaged state, and a series of shifts related to the downshift is performed. Control is completed (see time t9). In the present embodiment, regenerative energy can be increased as compared with the comparative example. Although not shown, in comparison with the comparative example in which the downshift of the automatic transmission 24 is not started until the absolute value of the residual regenerative braking torque ΔTBr becomes equal to or less than a predetermined torque difference ΔTBrf, the present embodiment: It is possible to speed up the transition to the optimum gear stage.

As described above, according to the present embodiment, when it is determined that the automatic transmission 24 should downshift while the regenerative control of the electric motor MG is being performed, the downshift phase is changed to the preparation phase. Since the shift is started, the downshift delay time can be shortened compared to delaying the start of the downshift until the absolute value of the residual regenerative braking torque ΔTBr becomes equal to or less than the predetermined torque difference ΔTBrf. Further, even if the preparatory phase is completed, the downshift phase is maintained in the state where the preparatory phase is completed until the absolute value of the residual regenerative braking torque ΔTBr becomes equal to or less than the predetermined torque difference ΔTBrf. becomes equal to or less than the predetermined torque difference .DELTA.TBrf, the torque phase is started and the downshift proceeds. The regenerative braking torque TBrr is brought close to the target regenerative braking torque TBrt. Therefore, when it is determined to downshift the automatic transmission 24 during regenerative control of the electric motor MG, it is possible to suppress a delay in progress of the downshift while suppressing a decrease in energy efficiency.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other aspects.

For example, in the above embodiment, the required braking torque TBdem was set based on the driver's brake operation, but the present invention is not limited to this. For example, the required braking torque TBdem may be set based on a brake request in known automatic driving control, a brake request in known automobile speed control, or the like.

In the above embodiment, the start of the torque phase is delayed until the absolute value of the residual regenerative braking torque .DELTA.TBr becomes equal to or less than the predetermined torque difference .DELTA.TBrf. may force the torque phase to start.

Further, in the above embodiment, the vehicle 10 including the engine 12, the electric motor MG, and the automatic transmission 24 was illustrated as the vehicle to which the present invention is applied, but the present invention is not limited to this aspect. For example, the present invention can be applied to an electric vehicle that does not have an engine and uses only an electric motor as a driving force source, a hybrid vehicle that has an automatic transmission in series after a known electric continuously variable transmission, and the like. can. In short, the electric motor constitutes a part of the power transmission path between the electric motor and the drive wheels, and the engagement of any one of the plurality of engagement devices causes the gear to be set to any one of a plurality of gear stages. The present invention can be applied to any vehicle provided with an automatic transmission in which gears are formed.

Further, in the above-described embodiment, the automatic transmission 24 is a planetary gear type automatic transmission, but it is not limited to this aspect. The automatic transmission 24 may be a known DCT (Dual Clutch Transmission) or the like. In short, the automatic transmission 24 is an automatic transmission in which any one of a plurality of gear stages is formed by engagement of any one of a plurality of engagement devices, and is an automatic transmission in which any one of a plurality of gear stages is formed. Any automatic transmission that shifts gears by switching the device to the released state and switching the engagement side engagement device to the engaged state may be used. In the case of the DCT, the plurality of engagement devices are engagement devices connected to respective input shafts of two systems, one of the plurality of engagement devices corresponds to the release side engagement device, and the plurality of engagement devices The other corresponds to the engagement side engagement device.

Further, in the above-described embodiment, the torque converter 22 is used as the hydrodynamic transmission device, but the present invention is not limited to this aspect. For example, instead of the torque converter 22, another hydrodynamic transmission such as a fluid coupling that does not amplify torque may be used as the hydrodynamic transmission. Alternatively, the hydrodynamic transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

It should be noted that what has been described above is just one embodiment, and the present invention can be implemented in aspects with various modifications and improvements based on the knowledge of those skilled in the art.

10: Vehicle 14: Drive wheel 24: Automatic transmission 90: Electronic control device (control device)
92b: Electric motor control unit 94: Shift control unit CB: Engagement device MG: Electric motor

Claims (1)

The electric motor constitutes a part of the power transmission path between the electric motor and the drive wheels, and engagement of any one of the plurality of engagement devices forms any one of the plurality of gear stages. A control device for a vehicle, comprising:
The shift of the automatic transmission is performed by switching a disengagement-side engagement device among the engagement devices to a released state and switching an engagement-side engagement device among the engagement devices to an engaged state. a shift control unit that performs
an electric motor control unit that performs regenerative control of the electric motor for controlling an actual value of the regenerative braking torque, which is the braking torque generated by the regeneration of the electric motor, so as to achieve a target value;
contains
When the shift control unit determines that the automatic transmission is to downshift while regeneration control of the electric motor is being performed, the shift control unit determines the progress stage of the downshift by setting the disengagement side engagement device to the automatic shift control unit. The downshift is started so as to make the engine stand by with a torque capacity that can handle the input torque to the machine and prepare the engagement side engagement device to be in a packing completion state in which the pack clearance is narrowed. Even after the preparation stage is completed, the absolute value of the torque difference between the target value and the actual value of the regenerative braking torque is such that the actual value approaches the target value to the extent that a decrease in energy efficiency can be suppressed. The advance stage is maintained in a state in which the preparation stage is completed until the torque difference becomes equal to or less than a predetermined torque difference, and the preparation stage is started after the absolute value of the torque difference becomes equal to or less than the predetermined torque difference. A control device for a vehicle, characterized in that the downshift is advanced by starting a torque phase, which is the next advancing stage.

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