Vehicle control device

Abstract

To suppress a reduction in the learning frequency while suppressing erroneous learning of packing learning of a lockup clutch when starting or stopping an engine is overlapped while executing the packing learning.SOLUTION: During execution of packing learning, in a case where an engine is started or stopped when an elapsed period of time from a start point of packing control is longer than a target value of a packing completion time, a point of time of starting or stopping the engine is determined to be a point of time where the packing is completed, and instruction pressure of a lockup clutch to be used for the next packing control is corrected toward higher pressure side. Therefore, in a case where the instruction pressure of the lockup clutch is determined to be in shortage at the point in time of starting or stopping the engine, the instruction pressure can be corrected toward higher pressure, and it is possible to prevent the packing completion time from being unstably calculated during a start transition or stop transition of the engine.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle equipped with a disconnecting clutch provided between an engine and an electric motor, and a fluid-type power transmission with a lock-up clutch provided between the electric motor and drive wheels. [Background technology]

[0002] A well-known vehicle control device includes an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to transmit power, a disconnecting clutch disposed between the engine and the electric motor in the power transmission path for connecting and disconnecting the engine from the electric motor, and a fluid-type power transmission device having a lock-up clutch disposed in the power transmission path between the electric motor and the drive wheels. Patent Document 1 discloses an example of such a vehicle control device. Patent Document 1 discloses starting the engine by igniting the engine while switching the disconnecting clutch from a released state to an engaged state while allowing the lock-up clutch to slip. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-73705 Summary of the Invention [Problem to be solved by the invention]

[0004] To improve the control accuracy when switching a lockup clutch from a released state to a slip state or an engaged state, packing learning is sometimes performed, in which the command pressure of the lockup clutch used for packing control is corrected through learning based on the packing completion time required from the start of packing control of the lockup clutch to the packing completion state. Meanwhile, during electric vehicle (BEV) driving, in which the vehicle runs using only the electric motor as a power source with the engine stopped, the disconnecting clutch is in a released state, but is switched to an engaged state when the engine is started. Meanwhile, during engine driving, in which the vehicle runs using at least the engine as a power source (HEV) the disconnecting clutch is in an engaged state, but is switched to a released state when the engine is stopped. Therefore, if the engine starts or stops while packing learning is being performed, the rotational speed of the electric motor fluctuates due to the switching between the engaged and disengaged states of the disconnecting clutch, and the input rotational speed of the lockup clutch also fluctuates. In this case, fluctuations in the lockup clutch differential rotation speed may occur due to factors other than the completion of packing of the lockup clutch. This makes it difficult to stably calculate the packing completion time, which could result in erroneous learning of the lockup clutch command pressure. On the other hand, if packing learning is uniformly prohibited when engine start or stop occurs during packing learning, the number of opportunities to perform packing learning will decrease, which could result in a decrease in the frequency of learning the lockup clutch command pressure.

[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 suppress erroneous learning of packing learning while suppressing a decrease in learning frequency when the engine is started or stopped while packing learning of a lock-up clutch is being performed. [Means for solving the problem]

[0006] The gist of a first invention is a control device for a vehicle including: (a) an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be able to transmit power, a disconnecting clutch provided in the power transmission path between the engine and the electric motor for connecting and disconnecting the engine from the electric motor, and a hydrodynamic power transmission device provided in the power transmission path between the electric motor and the drive wheels and having a lock-up clutch, (b) a lock-up clutch control unit that controls the lock-up clutch to be in one of a released state, a slip state, and an engaged state, and that executes pack filling control that controls the lock-up clutch to change from the released state to a pack filling completion state in which pack clearance is closed; and (c) a control unit that switches the disconnecting clutch from the released state to the engaged state when the engine is started. and (d) a learning control unit that performs packing learning to correct, by learning, the command pressure of the lockup clutch used in the packing control based on the packing completion time required from the start of the packing control to reach the packing completion state, and (e) when the engine is started or stopped while the time elapsed from the start of the packing control is longer than the target value of the packing completion time during the packing learning, the learning control unit determines that the time when the engine started or stopped was started as the time when the packing completion state was reached, and corrects the command pressure of the lockup clutch used in the next packing control to the pressure-increasing side. [Effects of the Invention]

[0007] According to the first aspect of the present invention, if the engine is started or stopped while packing learning is in progress and the elapsed time since the start of packing control is longer than the target value for the packing completion time, the time when the engine is started or stopped is determined to be the time when the packing is completed, and the command pressure of the lock-up clutch used for the next packing control is corrected to the pressure-increasing side. Therefore, if it is determined that the command pressure of the lock-up clutch is insufficient at the time when the engine is started or stopped, the command pressure can be corrected to the pressure-increasing side, and an unstable calculation of the packing completion time during the engine starting transition or stopping transition can be avoided. Therefore, when the engine is started or stopped while lock-up clutch packing learning is in progress, erroneous learning of packing learning can be suppressed and a decrease in learning frequency can be suppressed. [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] FIG. 10 is a diagram showing an example of a time chart when acceleration slip control is executed. [Figure 3] This is a flowchart explaining the main parts of the control operation of the electronic control device, and is a flowchart explaining the control operation for suppressing erroneous learning of LU clutch pack end pressure while suppressing a decrease in learning frequency when the engine starts or stops while LU clutch pack end pressure learning is being performed. 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 a hybrid vehicle equipped with an engine 12 and an electric motor MG that function as a power source SP. The vehicle 10 also has 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 such as a gasoline engine, a diesel engine, etc. An electronic control device 90 (described later) controls an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, etc., provided in the vehicle 10, thereby controlling the engine torque Te, which is the output torque of the engine 12.

[0012] The electric motor MG is a rotating electric machine, a so-called motor generator, that functions as a motor that generates mechanical power from electric power and as a generator that generates electric power from mechanical power. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The battery 54 is an electricity storage device that supplies and receives electric power to the electric motor MG. The inverter 52 is controlled by an electronic control device 90 (described later), thereby controlling the MG torque Tm, which is the output torque of the electric motor MG. For example, when the rotation direction of the electric motor MG is forward, which is the same as the rotation direction when the engine 12 is operating, the MG torque Tm is a power torque when the positive torque is on the acceleration side, and a regenerative torque when the negative torque is on the deceleration side. The electric power also refers to electric energy unless otherwise specified. The power also refers to driving force, torque, and force unless otherwise specified.

[0013] The power transmission device 16 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, and the like, housed within a case 18, which is a non-rotating member attached to the vehicle body. The K0 clutch 20 is a clutch provided between the engine 12 and the electric motor MG in a power transmission path between the engine 12 and the drive wheels 14. The torque converter 22 is connected to the engine 12 via the K0 clutch 20. The automatic transmission 24 is connected to the torque converter 22 and is interposed in the power transmission path between the torque converter 22 and the drive wheels 14. The power transmission device 16 also includes a propeller shaft 28 connected to a transmission output shaft 26, which is an output rotating member of the automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, a pair of drive shafts 32 connected to the differential gear 30, and the like. The power transmission device 16 also includes an engine connecting shaft 34 that connects the engine 12 and the K0 clutch 20, an electric motor connecting shaft 36 that connects the K0 clutch 20 and the torque converter 22, and the like.

[0014] The electric motor MG is connected to the electric motor connecting shaft 36 in 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 engine 12 and the drive wheels 14, particularly to the power transmission path between the K0 clutch 20 and the torque converter 22. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 so as to be able to transmit power without passing through the K0 clutch 20.

[0015] The torque converter 22 includes a pump wheel 22a connected to an electric motor connecting shaft 36 and a turbine wheel 22b connected to a transmission input shaft 38, which is an input rotating member of the automatic transmission 24. The pump wheel 22a is the input member of the torque converter 22, and the turbine wheel 22b is the output member of the torque converter 22. The electric motor connecting shaft 36 is also the input rotating member of the torque converter 22. The transmission input shaft 38 is also the output rotating member of the torque converter 22, formed integrally with a turbine shaft that is rotationally driven by the turbine wheel 22b. The torque converter 22 is a fluid transmission device that is provided between the electric motor MG and the drive wheels 14 in the power transmission path between the engine 12 and the drive wheels 14 and transmits power from the power source SP from the electric motor connecting shaft 36 to the transmission input shaft 38 via fluid. The torque converter 22 includes an LU clutch 40 that connects the pump wheel 22a and the turbine wheel 22b, that is, that connects the motor connecting shaft 36 and the transmission input shaft 38. The LU clutch 40 is a direct coupling clutch that connects the input and output rotary members of the torque converter 22, that is, a known lock-up clutch.

[0016] The LU clutch 40 is a hydraulic friction engagement device configured, for example, with a multi-plate or single-plate clutch. The LU clutch 40 switches its operating state, i.e., its control state, by changing the LU torque Tlu, which is the torque capacity of the LU clutch 40, using the LU oil pressure PRlu, which is a regulated oil pressure supplied from a hydraulic control circuit 56 provided in the vehicle 10. The control states of the LU clutch 40 include a release state (also referred to as a fully released state) in which the LU clutch 40 is released, a slip state in which the LU clutch 40 is engaged with slippage, and an engagement state (also referred to as a fully engaged state) in which the LU clutch 40 is engaged. When the LU clutch 40 is in the release state, the torque converter 22 is in a torque converter state in which torque amplification is achieved. When the LU clutch 40 is in the engaged state, the torque converter 22 is in a lock-up state in which the pump wheel 22a and the turbine wheel 22b rotate integrally.

[0017] The automatic transmission 24 is a known planetary gear automatic transmission that includes, for example, one or more planetary gear devices (not shown) and an engagement device CB. The engagement device CB includes, for example, a plurality of known hydraulic friction engagement devices. Each engagement device CB has its torque capacity (CB torque Tcb) changed by a CB oil pressure PRcb, which is a regulated oil pressure supplied from a hydraulic control circuit 56, thereby switching between control states such as an engaged state, a slip state, and a disengaged state.

[0018] The automatic transmission 24 is a stepped transmission in which one of a plurality of gear stages (also referred to as gear stages) with different speed ratios (also referred to as gear ratios) γat (=AT input rotation speed Ni / AT output rotation speed No) is established by engaging one of the engagement devices CB. The automatic transmission 24 switches between gear stages established by an electronic control device 90 (described later) in response to the accelerator operation of the driver (=operator), the vehicle speed V, etc. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38, and is the input rotation speed of the automatic transmission 24. The AT input rotation speed Ni is equivalent to the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22, i.e., the torque converter output rotation speed. The AT input rotation speed Ni can be expressed in terms of the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26, and is the output rotation speed of the automatic transmission 24.

[0019] The K0 clutch 20 is a hydraulic friction engagement device configured, for example, with a multi-plate or single-plate clutch. The K0 clutch 20 switches between control states such as an engaged state, a slip state, and a released state by changing the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, using the K0 oil pressure PRk0, which is the adjusted oil pressure supplied from the hydraulic control circuit 56.

[0020] In the vehicle 10, when the K0 clutch 20 is engaged, the engine 12 and the torque converter 22 are connected to each other so that power can be transmitted between them. On the other hand, when the K0 clutch 20 is disengaged, power transmission between the engine 12 and the torque converter 22 is interrupted. Because the electric motor MG is connected to the torque converter 22, the K0 clutch 20 functions as a connecting / disconnecting clutch that connects and disconnects the engine 12 from the electric motor MG.

[0021] 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 connecting shaft 34 to the drive wheels 14 via the K0 clutch 20, the electric motor connecting shaft 36, the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in this order. Furthermore, regardless of the control state of the K0 clutch 20, the power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the drive wheels 14 via the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in this order.

[0022] The vehicle 10 is equipped with a MOP 58 which is a mechanical oil pump, an EOP 60 which is an electric oil pump, a pump motor 62, etc. The MOP 58 is connected to the pump impeller 22a and is driven to rotate by a power source SP to discharge hydraulic oil OIL used in the power transmission device 16. The pump motor 62 is a motor dedicated to the EOP 60 for driving the EOP 60 to rotate. The EOP 60 is driven to rotate by the pump motor 62 to discharge hydraulic oil OIL. The hydraulic oil OIL discharged by the MOP 58 and EOP 60 is supplied to a hydraulic control circuit 56. The hydraulic control circuit 56 supplies a CB hydraulic pressure PRcb, a K0 hydraulic pressure PRk0, an LU hydraulic pressure PRlu, etc., each adjusted based on the hydraulic oil OIL discharged by the MOP 58 and / or EOP 60.

[0023] The vehicle 10 further includes an electronic control device 90 that includes a control device for the vehicle 10. The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing in accordance with programs stored in the ROM in advance while utilizing the temporary storage function of the RAM. The electronic control device 90 includes computers for engine control, electric motor control, clutch control, transmission control, etc. as necessary.

[0024] The electronic control device 90 is supplied with various signals based on detection values ​​from various sensors provided on the vehicle 10 (for example, an engine rotation speed sensor 70, a turbine rotation speed sensor 72, an output rotation speed sensor 74, an MG rotation speed sensor 76, an accelerator opening sensor 78, a throttle valve opening sensor 80, a brake switch 82, a battery sensor 84, an oil temperature sensor 86, etc.) (for example, an engine rotation speed Ne which is the rotation speed of the engine 12, a turbine rotation speed Nt which is the same value as the AT input rotation speed Ni, an AT output rotation speed No corresponding to the vehicle speed V, an MG rotation speed Nm which is the rotation speed of the electric motor MG, an accelerator opening θacc which is the amount of accelerator operation by the driver which indicates the magnitude of the driver's acceleration operation, a throttle valve opening θth which is the opening of the electronic throttle valve, a brake-on signal Bon which is a signal indicating the state in which the brake pedal for operating the wheel brakes is being operated by the driver, a battery temperature THbat, a battery charge / discharge current Ibat, a battery voltage Vbat of the battery 54, and a hydraulic oil temperature THoil which is the temperature of the hydraulic oil in the hydraulic control circuit 56). The MG rotation speed Nm is equal to the input rotation speed of the torque converter 22, that is, the torque converter input rotation speed.

[0025] The electronic control device 90 outputs various command signals (e.g., an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Scb for controlling the engagement device CB, a K0 hydraulic control command signal Sk0 for controlling the K0 clutch 20, an LU hydraulic control command signal Slu for controlling the LU clutch 40, an EOP control command signal Seop for controlling the EOP 60, etc.) to each device provided in the vehicle 10 (e.g., the engine control device 50, the inverter 52, the hydraulic control circuit 56, the pump motor 62, etc.).

[0026] Each hydraulic control command signal S will be described using the LU hydraulic control command signal Slu as an example. The electronic control device 90 calculates an LU clutch command pressure Splu, which is a command pressure for the LU clutch 40 to supply the LU hydraulic pressure PRlu adjusted by the hydraulic control circuit 56, as a command value for the LU hydraulic pressure PRlu. The command pressure is a target hydraulic pressure commanded by the electronic control device 90 for the hydraulic oil OIL supplied to the engagement device, and the actual hydraulic pressure, which is the actual hydraulic pressure supplied to the engagement device, changes depending on this command pressure. The electronic control device 90 converts the LU clutch command pressure Splu into an LU command current value Silu for driving the LU solenoid SLlu provided in the hydraulic control circuit 56. The LU solenoid SLlu is a solenoid valve for the LU clutch 40 that outputs the LU hydraulic pressure PRlu. The LU command current value Silu is a command current for a solenoid driver, which is a drive circuit provided in the electronic control device 90 that drives the LU solenoid SLlu. The LU hydraulic control command signal Slu is a drive current or drive voltage for the solenoid driver to drive the LU solenoid SLlu based on the LU command current value Silu. In other words, the LU clutch command pressure Splu is converted into the LU hydraulic control command signal Slu and output to the hydraulic control circuit 56. In this embodiment, for convenience, the LU clutch command pressure Splu and the LU hydraulic control command signal Slu are treated as the same.

[0027] In order to realize various controls in the vehicle 10, the electronic control device 90 is equipped with a power source control means, i.e., a power source control unit 92, a K0 clutch control means, i.e., a K0 clutch control unit 94, a transmission control means, i.e., a transmission control unit 96, an LU clutch control means, i.e., an LU clutch control unit 98, and a learning control means, i.e., a learning control unit 99.

[0028] The power source control unit 92 includes a function as engine control means, i.e., engine control unit 92a, that controls the operation of the engine 12, and a function as electric motor control means, i.e., electric motor control unit 92b, that controls the operation of the electric motor MG via the inverter 52, and is a hybrid control means, i.e., a hybrid control unit, that performs hybrid drive control using the engine 12 and the electric motor MG using these control functions.

[0029] The power source control unit 92 calculates the amount of driving demanded by the driver for the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand map. The driving demand map is a relationship that is experimentally or design-based and stored in advance, i.e., a predetermined relationship. The driving demand is, for example, the required driving torque Trdem at the drive wheels 14. In other words, the required driving torque Trdem [Nm] is the required driving power Prdem [W] at the current vehicle speed V. The driving demand may also be the required driving force Frdem [N] at the drive wheels 14 or the required AT output torque at the transmission output shaft 26. In calculating the driving demand, the AT output rotation speed No may be used instead of the vehicle speed V. The power source control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the electric motor MG so as to realize the required driving power Prdem, taking into account transmission loss, auxiliary load, the gear ratio γat of the automatic transmission 24, etc.

[0030] When the required drive torque Trdem can be satisfied by the output of the electric motor MG alone, the power source control unit 92 establishes the motor drive mode, i.e., the BEV drive mode, as the drive mode for driving the vehicle 10. The BEV drive mode is an electric drive mode that enables motor driving, i.e., electric driving (=BEV driving), in which the vehicle runs using only the electric motor MG as the power source SP with the K0 clutch 20 disengaged and the engine 12 stopped. On the other hand, when the required drive torque Trdem cannot be satisfied without using at least the output of the engine 12, the power source control unit 92 establishes the engine drive mode, i.e., the HEV drive mode, as the drive mode. The HEV drive mode is a hybrid drive mode that enables engine driving, i.e., hybrid driving (=HEV driving), in which the vehicle runs using at least the engine 12 as the power source SP with the K0 clutch 20 engaged. On the other hand, even if the required drive torque Trdem can be satisfied by the output of the electric motor MG alone, the power source control unit 92 establishes the HEV drive mode as the drive mode when, for example, the battery 54 needs to be charged, the engine 12 needs to be warmed up, or the hydraulic oil temperature THoil is extremely low.

[0031] The power source control unit 92, particularly the engine control unit 92a, determines whether or not there is an engine start request, which is a request to start the engine 12 and switch the control state of the engine 12 from a stopped state to an operating state. For example, in the BEV drive mode, the engine control unit 92a determines whether or not there is an engine start request based on whether or not the required drive torque Trdem has increased beyond a range that can be covered by the output of the electric motor MG alone, whether or not the engine 12 and the like need to be warmed up, or whether or not the battery 54 needs to be charged.

[0032] When the engine control unit 92a determines that there is an engine start request, the K0 clutch control unit 94 controls the K0 clutch 20 to execute start control of the engine 12. For example, the K0 clutch control unit 94 outputs a K0 hydraulic control command signal Sk0 to the hydraulic control circuit 56 to control the K0 clutch 20 from a released state toward an engaged state so as to obtain a K0 torque Tk0 for transmitting the cranking torque Tcr to the engine 12. The cranking torque Tcr is a predetermined torque required for cranking the engine 12 to increase the engine rotation speed Ne.

[0033] When it is determined that there is an engine start request, the power source control unit 92 controls the engine 12 and the electric motor MG to execute start control of the engine 12. For example, in conjunction with switching the K0 clutch 20 to the engaged state, the electric motor control unit 92b outputs an MG control command signal Sm to the inverter 52 for causing the electric motor MG to output cranking torque Tcr. Furthermore, in conjunction with the cranking of the engine 12, the engine control unit 92a outputs an engine control command signal Se to the engine control device 50 for starting fuel supply, engine ignition, and the like.

[0034] The power source control unit 92, particularly the engine control unit 92a, determines whether there is an engine stop request, which is a request to stop the engine 12 by switching the control state of the engine 12 from a running state to a stopped state. For example, in the HEV drive mode, the engine control unit 92a determines whether there is an engine stop request based on whether the required drive torque Trdem is within a range that can be covered by the output of the electric motor MG alone, whether warming up the engine 12 and the like is unnecessary, whether charging the battery 54 is unnecessary, and so on.

[0035] When the engine control unit 92a determines that there is an engine stop request, it outputs an engine control command signal Se to the engine control device 50 to gradually reduce the engine torque Te. When the engine control unit 92a determines that there is an engine stop request, the K0 clutch control unit 94 outputs a K0 hydraulic control command signal Sk0 to the hydraulic control circuit 56 to control the K0 clutch 20 from the engaged state toward the released state after the engine control unit 92a gradually reduces the engine torque Te. After the K0 clutch control unit 94 switches the K0 clutch 20 to the released state, the engine control unit 92a outputs an engine control command signal Se to the engine control device 50 to perform a fuel cut that stops the supply of fuel to the engine 12.

[0036] In this way, the K0 clutch control unit 94 is a disconnecting clutch control unit that switches the K0 clutch 20 from a released state to an engaged state when the engine 12 is started, and switches the K0 clutch 20 from an engaged state to a released state when the engine 12 is stopped.

[0037] The transmission control unit 96 determines whether to shift the automatic transmission 24 using, for example, a shift map, which is a predetermined relationship, and outputs a CB hydraulic control command signal Sbc to the hydraulic control circuit 56 as needed, i.e., depending on the result of the shift determination. In controlling the shift of the automatic transmission 24, the transmission control unit 96 performs shifting of the automatic transmission 24, for example, by switching a disengaging engagement device among the engagement devices CB to a disengaged state and switching an engaging engagement device among the engagement devices CB to an engaged state. The shift map is a predetermined relationship having shift lines on a two-dimensional coordinate system using, for example, vehicle speed V and required drive torque Trdem as variables, for determining whether to shift the automatic transmission 24. In the shift map, the AT output rotation speed No or the like may be used instead of the vehicle speed V, and the required drive force Frdem, accelerator opening θacc, throttle valve opening θth, or the like may be used instead of the required drive torque Trdem.

[0038] The LU clutch control unit 98 is a lock-up clutch control unit that controls the LU clutch 40 to be in one of the control states of released, slipped, and engaged, i.e., controls the control state of the LU clutch 40. Specifically, the LU clutch control unit 98 determines the control region using, for example, a lock-up region diagram, which is a predetermined relationship, and outputs an LU hydraulic control command signal Slu to the hydraulic control circuit 56 to supply the LU clutch 40 with an LU hydraulic pressure PRlu that achieves the control state corresponding to the determined control region. The lock-up region diagram is a predetermined relationship that has a fully released region (i.e., lock-up off region), a slip region, and a fully engaged region (i.e., lock-up region) on a two-dimensional coordinate system with, for example, vehicle speed V and required drive torque Trdem as variables. During BEV driving, the K0 clutch 20 is released and no control is required to avoid engine stalling. Therefore, in BEV drive mode, a lock-up off region is set in the low vehicle speed range near a stop, and a slip region or lock-up region is set so that the LU clutch 40 is not released in the range other than the low vehicle speed range in order to improve power transmission efficiency.

[0039] When the LU clutch control unit 98 determines that the control region is the lock-up region, it sets the LU hydraulic pressure PRlu to obtain the LU torque Tlu capable of transmitting the input torque to the LU clutch 40, i.e., the LU input torque Tinlu, and executes lock-up control of the LU clutch 40, thereby bringing the LU clutch 40 into a fully engaged state. The LU input torque Tinlu is the total torque of the engine torque Te and the MG torque Tm during HEV driving, and is the MG torque Tm during BEV driving. The LU torque Tlu capable of transmitting the LU input torque Tinlu is, for example, a torque value obtained by multiplying the LU input torque Tinlu by a safety factor (>1).

[0040] If the LU torque Tlu is small relative to the LU input torque Tinlu, slippage occurs in the LU clutch 40. When the LU clutch control unit 98 determines that the control region is the slip region, it executes slip control of the LU clutch 40 by setting the LU hydraulic pressure PRlu to achieve the target LU slip amount Nslplut, which is the target value of the LU slip amount Nslplu, for the LU input torque Tinlu, thereby placing the LU clutch 40 in a desired slip state. The LU slip amount Nslplu is the difference (= Nm - Nt) between the torque converter input rotation speed (= MG rotation speed Nm) and the torque converter output rotation speed (= turbine rotation speed Nt). During HEV driving, the engine rotation speed Ne may be used instead of the MG rotation speed Nm. In the lockup region diagram, the slip region is set, for example, at a lower vehicle speed compared to the lockup region, and is a region where lockup control is difficult to implement and a slip state is established to improve energy efficiency and drivability. The slip region is also a region that is set in consideration of drivability, muffled noise, etc. (for example, NV (noise and vibration) performance).

[0041] During slip control of the LU clutch 40, the LU clutch control unit 98 corrects the LU hydraulic pressure PRlu, i.e., the LU torque Tlu, through feedback control so that the actual LU slip amount Nslplur, which is the actual value of the LU slip amount Nslplu, becomes the target LU slip amount Nslplut. The LU clutch control unit 98 corrects the LU torque Tlu by adding the feedback LU hydraulic pressure PRlufb, which serves as a feedback amount, to the feedforward LU hydraulic pressure PRluff, which serves as a feedforward amount of the LU hydraulic pressure PRlu. The feedback LU hydraulic pressure PRlufb is a correction amount for the LU hydraulic pressure PRlu that corrects the feedforward LU hydraulic pressure PRluff. The LU clutch control unit 98 calculates the feedforward LU hydraulic pressure PRluff using, for example, a map or function in which values ​​corresponding to the LU input torque Tinlu and the target LU slip amount Nslplut are predetermined. The map or function is predetermined so that, for example, the feedforward LU hydraulic pressure PRluff becomes larger as the LU input torque Tinlu becomes larger. The LU clutch control unit 98 calculates the feedback LU oil pressure PRlufb using a predetermined feedback control equation having a proportional term (P component), an integral term (I component), and a derivative term (D component) based on, for example, the slip amount difference (=Nslpr-Nslpt) as the difference between the actual LU slip amount Nslplur and the target LU slip amount Nslplut. Examples of slip control for the LU clutch 40 include acceleration slip control when the control region reaches the slip region, particularly the acceleration slip region, after acceleration from start, and deceleration slip control executed when decelerating with the accelerator released.

[0042] FIG. 2 is a diagram showing an example of a time chart when acceleration slip control is executed. In FIG. 2, time t1 indicates the time when packing control of the LU clutch 40, i.e., LU packing control, is initiated, for example, during start acceleration in the BEV drive mode, when it is determined that the control region has reached the acceleration slip region. Packing control is a control for bringing the friction engagement device into a packing-completed state, i.e., a packing-completed state, in which pack clearances in the friction plates of the friction engagement device have been reduced. The packing-completed state of the friction engagement device is a state in which the friction engagement device begins to have torque capacity by increasing the hydraulic pressure supplied to the friction engagement device from the packing-completed state. The LU packing control is packing control, i.e., engagement preparation control, for controlling the LU clutch 40 to change from a released state to a packing-completed state. In this manner, the LU clutch control unit 98 executes the LU packing control. In LU packing control, first, in order to improve the initial responsiveness of the LU hydraulic pressure PRlu, quick apply (=QA) is executed to output an LU clutch command pressure Splu that is a temporarily high rapid filling pressure (see time t1-t2), and then, in order to complete packing of the LU clutch 40, constant pressure standby for packing is executed to wait at a constant pressure, that is, to output an LU clutch command pressure Splu that is a constant pressure standby pressure (see time t2-t3). After a predetermined QA time and constant pressure standby time A, which are the times required for LU packing control, have elapsed from the start of LU packing control, acceleration slip control is started (see time t3). In the acceleration slip control, a constant pressure standby for slip control is executed to output an LU clutch command pressure Splu that is a constant standby pressure higher than that during constant pressure standby for packing so that the actual LU slip amount Nslplur approaches the target LU slip amount Nslplut (see time points t3-t4), and then a sweep-up is executed to gradually increase the LU clutch command pressure Splu (see time points t4-t5).After that, differential rotation control is executed to correct the LU clutch command pressure Splu through feedback control so that the actual LU slip amount Nslplur becomes the target LU slip amount Nslplut (see time points t5-t6).When it is determined that the control region has reached the lock-up region, the LU clutch command pressure Splu is increased in a stepped manner so that the LU clutch 40 is fully engaged (see time t6), and lock-up control of the LU clutch 40 is executed to maintain the LU clutch 40 in a lock-up state (see time t6 and thereafter).

[0043] The learning control unit 99 performs pack filling learning to correct, through learning, the LU clutch command pressure Splu used for LU pack filling control, i.e., the LU pack filling control command pressure Splupp (see FIG. 2), when the LU clutch 40 is switched from the released state to the slip state or the engaged state, i.e., pack filling learning of the LU clutch 40. The LU pack filling control command pressure Splupp that brings the LU clutch 40 into the pack filling complete state is the pack end pressure of the LU clutch 40, and in this embodiment, the pack filling learning of the LU clutch 40 is referred to as LU clutch pack end pressure learning.

[0044] Specifically, the learning control unit 99 performs LU clutch pack end pressure learning based on the time required for the LU clutch 40 to reach the packing completion state from the start of the LU packing control, i.e., the LU packing completion time TMlupk. The learning control unit 99 determines whether the LU clutch 40 has reached the packing completion state, for example, based on whether the rate of change of the actual LU slip amount Nslplur is equal to or greater than a predetermined rate of change ΔNslpf. The predetermined rate of change ΔNslpf is a predetermined threshold value used to determine whether the change in the actual LU slip amount Nslplur has reached the packing completion state. The learning control unit 99 calculates the period from the start of the LU packing control to the time it is determined that the LU clutch 40 has reached the packing completion state as the LU packing completion time TMlupk. The learning control unit 99 corrects the LU packing control command pressure Splupk by, for example, correcting at least one of the rapid filling pressure, QA time, constant pressure standby pressure, and constant pressure standby time A in the LU packing control.

[0045] If the LU packing completion time TMlupk is longer than the LU packing completion target time TMlupkt, the learning control unit 99 determines that the LU packing control command pressure Splupk was insufficient and corrects the LU packing control command pressure Splupk to increase it. For example, if the LU packing completion time TMlupk is longer than the LU packing completion target time TMlupkt, the learning control unit 99 corrects the LU packing control command pressure Splupk in the next LU packing control to increase it by at least one of increasing the rapid filling pressure, lengthening the QA time, increasing the constant pressure standby pressure, and lengthening the constant pressure standby time A, with respect to the LU packing control command pressure Splupk in the current LU packing control. On the other hand, if the LU packing completion time TMlupk is shorter than the LU packing completion target time TMlupkt, the learning control unit 99 determines that the LU packing control command pressure Splupk is excessive and corrects the LU packing control command pressure Splupk to a reduced value. For example, if the LU packing completion time TMlupk is shorter than the LU packing completion target time TMlupkt, the learning control unit 99 corrects the LU packing control command pressure Splupk in the next LU packing control to a reduced value by reducing the LU packing control command pressure Splupk in the current LU packing control by at least one of lowering the rapid filling pressure, shortening the QA time, lowering the constant pressure standby pressure, and shortening the constant pressure standby time A. The LU packing completion target time TMlupkt is a target value of the LU packing completion time TMlupk that is predetermined in consideration of, for example, responsiveness and shock suppression.

[0046] For example, when the LU clutch 40 is switched from a released state to a slip state or an engaged state during BEV driving, the engine 12 may be started due to an increase in the required drive torque Trdem during LU clutch pack end pressure learning. Alternatively, when the LU clutch 40 is switched from a released state to a slip state or an engaged state during HEV driving due to the need to charge the battery 54, the engine 12 may be stopped during LU clutch pack end pressure learning because charging of the battery 54 is no longer necessary. Because the K0 clutch 20 is switched to an engaged state during the engine 12 startup transition, or because the K0 clutch 20 is switched to a released state during the engine 12 shutdown transition, the MG rotation speed Nm, i.e., the torque converter input rotation speed, may fluctuate, potentially causing fluctuations in the LU slip amount Nslplu. In other words, fluctuations in the LU slip amount Nslplu may occur due to factors other than the LU clutch 40 entering a fully packed state. Therefore, if the engine 12 starts or stops while LU clutch pack end pressure learning is being performed, it becomes difficult to stably calculate the LU pack filling completion time TMlupk, and there is a risk that the LU pack filling control command pressure Splupk will be erroneously learned. On the other hand, if the LU clutch pack end pressure learning is uniformly prohibited when the engine 12 starts or stops while LU clutch pack end pressure learning is being performed, there will be fewer opportunities to learn the LU clutch pack end pressure, and there is a risk that the frequency with which the LU pack filling control command pressure Splupk will be learned will decrease.

[0047] Therefore, when the engine 12 starts or stops while LU clutch pack end pressure learning is being performed, if the LU clutch 40 has not been determined to have reached the packing completion state and the engine 12 starts or stops before the elapsed time from the start of LU packing control, i.e., the packing start elapsed time TMprpk, exceeds the LU packing completion target time TMlupkt, the learning control unit 99 prohibits LU clutch pack end pressure learning and terminates LU clutch pack end pressure learning without correcting the LU packing control command pressure Splupk. On the other hand, when the start or stop of the engine 12 overlaps with the execution of LU clutch pack end pressure learning, if the start or stop of the engine 12 is initiated after the packing start elapsed time TMprpk exceeds the LU packing completion target time TMlupkt while it has not yet been determined that the LU clutch 40 has reached the packing completion state, the learning control unit 99 determines that the start or stop of the engine 12 was initiated as the time that the LU clutch 40 reached the packing completion state, determines that the LU packing control command pressure Splupk was insufficient, and corrects the LU packing control command pressure Splupk to the increased pressure side. In other words, if the start or stop of the engine 12 is initiated when the packing start elapsed time TMprpk is longer than the LU packing completion target time TMlupkt during LU clutch pack end pressure learning, the learning control unit 99 determines that the start or stop of the engine 12 was initiated as the time that the LU clutch 40 reached the packing completion state, and corrects the LU packing control command pressure Splupk to the increased pressure side. Basically, LU clutch pack end pressure learning begins at the start of LU pack filling control, and ends when it is determined that the LU clutch 40 has reached the pack filling completion state, i.e., when the LU pack filling completion time TMlupk is calculated and the LU pack filling control command pressure Splupk is corrected. The pack filling start elapsed time TMprpk is also the elapsed time from the start of LU clutch pack end pressure learning, i.e., the learning start elapsed time.

[0048] Specifically, during LU clutch pack end pressure learning, the learning control unit 99 determines whether the LU packing completion time TMlupk has been calculated, i.e., whether the LU packing completion time TMlupk has already been determined. If the learning control unit 99 determines that the LU packing completion time TMlupk has already been determined, the learning control unit 99 calculates a learned value as a correction amount for correcting the LU packing control command pressure Splupk based on the LU packing completion time TMlupk, and corrects the LU packing control command pressure Splupk for the next LU packing control. Note that the corrected LU packing control command pressure Splupk obtained by adding the correction amount calculated based on the LU packing completion time TMlupk may be used as the learned value. This correction amount may be either a positive or negative value.

[0049] If the learning control unit 99 determines that the LU packing completion time TMlupk has not been determined, it determines whether the packing start elapsed time TMprpk is longer than the LU packing completion target time TMlupkt. If the learning control unit 99 determines that the LU packing completion time TMlupk has not been determined, it determines whether the engine 12 is in a start transition or a stop transition, that is, whether the engine 12 has started to start or stop.

[0050] If the learning control unit 99 determines that the engine 12 is not in a start-up transition or a stop transition, it continues to determine whether the LU clutch 40 has reached the packing completion state, that is, it continues to calculate the LU packing completion time TMlupk.

[0051] When the learning control unit 99 determines that the packing start elapsed time TMprpk is within the LU packing completion target time TMlupkt, if it determines that the engine 12 is in a start-up transition or a stop transition, it prohibits LU clutch pack end pressure learning and terminates LU clutch pack end pressure learning without correcting the LU packing control command pressure Splupk.

[0052] When the learning control unit 99 determines that the packing start elapsed time TMprpk is longer than the LU packing completion target time TMlupkt and determines that the engine 12 is in a start transition or a stop transition, it sets the packing start elapsed time TMprpk at the time of initiation of start or stop of the engine 12 as the LU packing completion time TMlupk. The learning control unit 99 calculates a learning value for correcting the LU packing control command pressure Splupk based on the LU packing completion time TMlupk, i.e., the packing start elapsed time TMprpk that is longer than the LU packing completion target time TMlupkt, and corrects the LU packing control command pressure Splupk to the pressure-increasing side in the next LU packing control.

[0053] FIG. 3 is a flowchart explaining the main control operations of the electronic control unit 90, which is for suppressing erroneous learning of the LU clutch pack end pressure while suppressing a decrease in the learning frequency when the engine 12 is started or stopped while the LU clutch pack end pressure learning is being performed. This flowchart explains the control operations, which are executed, for example, from the start of the LU clutch pack end pressure learning.

[0054] In FIG. 3, each step in the flowchart corresponds to a function of the learning control unit 99. In step S10 (hereinafter, "step" is omitted), it is determined whether the LU packing completion time TMlupk has been determined. If the determination in S10 is negative, it is determined in S20 whether the packing start elapsed time TMprpk is longer than the LU packing completion target time TMlupkt. If the determination in S20 is negative, it is determined in S30 whether the engine 12 is in a start transition or a stop transition. If the determination in S20 is positive, it is determined in S40 whether the LU clutch 40 has reached a packing completion state, i.e., calculation of the LU packing completion time TMlupk continues. After S50, the process returns to S10. If the determination in S30 is positive, LU clutch pack end pressure learning is prohibited in S60. In this case, the LU clutch pack end pressure learning is terminated without correcting the LU pack filling control command pressure Splupk. If the determination in S40 above is affirmative, then in S70, the pack filling start elapsed time TMprpk at the time when the start or stop of the engine 12 is initiated is determined as the LU pack filling completion time TMlupk. If the determination in S10 above is affirmative, or following S70 above, in S80, a learned value of the LU pack filling control command pressure Splupk is calculated based on the LU pack filling completion time TMlupk. When executed following S70 above, the LU pack filling control command pressure Splupk is corrected to the increased pressure side based on the LU pack filling completion time TMlupk, which is set to the pack filling start elapsed time TMprpk that is longer than the LU pack filling completion target time TMlupkt.

[0055] As described above, according to this embodiment, if the engine 12 is started or stopped when the packing start elapsed time TMprpk is longer than the LU packing completion target time TMlupkt during LU clutch pack end pressure learning, the time when the engine 12 is started or stopped is determined to be the time when the packing is completed, and the LU packing control command pressure Splupk for the next LU packing control is corrected to the increased pressure side. Therefore, if it is determined that the LU packing control command pressure Splupk is insufficient at the time when the engine 12 is started or stopped, the LU packing control command pressure Splupk can be corrected to the increased pressure side, and an unstable calculation of the LU packing completion time TMlupk during the start or stop transition of the engine 12 can be avoided. Therefore, when the engine 12 starts or stops while LU clutch pack end pressure learning is being performed, erroneous learning of the LU clutch pack end pressure can be suppressed while a decrease in the learning frequency can be suppressed. Furthermore, by carrying out the LU clutch pack end pressure learning of this embodiment, it is possible to achieve both a reduction in shock when the LU clutch 40 is brought into the engaged state and an improvement in response.

[0056] 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.

[0057] For example, in the above-described embodiment, the target value of the LU packing completion time TMlupk may be the LU packing completion target time range. When the LU packing completion target time range is used as the target value of the LU packing completion time TMlupk, if the LU packing completion time TMlupk is within the LU packing completion target time range, the learning control unit 99 maintains the LU packing control instruction pressure Splupk for the current LU packing control for the next LU packing control. Furthermore, if the LU packing completion time TMlupk is longer than the maximum value of the LU packing completion target time range, the learning control unit 99 corrects the LU packing control instruction pressure Splupk to the increased pressure side. Furthermore, if the LU packing completion time TMlupk is shorter than the minimum value of the LU packing completion target time range, the learning control unit 99 corrects the LU packing control instruction pressure Splupk to the decreased pressure side. Furthermore, when the start or stop of the engine 12 overlaps while LU clutch pack end pressure learning is being performed, if the start or stop of the engine 12 is initiated before the packing start elapsed time TMprpk exceeds the maximum value of the LU packing completion target time range in a state where it has not been determined that the LU clutch 40 has reached the packing completion state, the learning control unit 99 prohibits LU clutch pack end pressure learning. Furthermore, when the start or stop of the engine 12 overlaps while LU clutch pack end pressure learning is being performed, if the start or stop of the engine 12 is initiated after the packing start elapsed time TMprpk exceeds the maximum value of the LU packing completion target time range in a state where it has not been determined that the LU clutch 40 has reached the packing completion state, the learning control unit 99 determines the time when the start or stop of the engine 12 was initiated as the time when the LU clutch 40 reached the packing completion state, and corrects the LU packing control command pressure Splupk to the increased pressure side.

[0058] In the above-described embodiment, the present invention is applied during execution of LU clutch pack end pressure learning during LU pack filling control during a transition from a released state to a slip state or an engaged state of the LU clutch 40, but the present invention is not limited to this. For example, the present invention can be applied even during execution of LU clutch pack end pressure learning during LU pack filling control that is executed only for LU clutch pack end pressure learning, rather than during a transition from a released state to a slip state or an engaged state.

[0059] In the above-described embodiment, a planetary gear automatic transmission is used as the automatic transmission 24, but the present invention is not limited to this. For example, the automatic transmission 24 may be a synchronous mesh parallel two-shaft automatic transmission including a known DCT (Dual Clutch Transmission), a known belt-type continuously variable transmission, or the like. The automatic transmission 24 is not necessarily provided.

[0060] Furthermore, in the above-described embodiment, the torque converter 22 is used as the fluid transmission device, but this is not limiting. For example, other fluid transmission devices, such as a fluid coupling that does not have a torque amplification function, may be used instead of the torque converter 22. In short, the present invention can be applied to any vehicle equipped with a power source including an engine and an electric motor, a disconnecting clutch provided between the engine and the electric motor, and a fluid transmission device with a lock-up clutch provided between the electric motor and the drive wheels.

[0061] 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]

[0062] 10: Vehicle 12: Engine 14: Drive wheel 20: K0 clutch (disconnecting clutch) 22: Torque converter (fluid transmission device) 40: LU clutch (lock-up clutch) 90: Electronic control device (control device) 94: K0 clutch control unit (connection / disconnection clutch control unit) 98: LU clutch control unit (lock-up clutch control unit) 99: Learning control unit MG: Electric motor

Claims

[Claim 1] A control device for a vehicle including an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be able to transmit power, a connecting / disconnecting clutch provided between the engine and the electric motor in the power transmission path for connecting / disconnecting the engine to / from the electric motor, and a fluid transmission device having a lock-up clutch provided between the electric motor and the drive wheels in the power transmission path, a lockup clutch control unit that controls the lockup clutch to be in one of a released state, a slip state, and an engaged state, and that executes pack filling control that controls the lockup clutch to change from the released state to a pack filling completion state in which the pack clearance is closed; a disconnection clutch control unit that switches the disconnection clutch from a released state to an engaged state when the engine is started and switches the disconnection clutch from an engaged state to a released state when the engine is stopped; a learning control unit that performs packing learning to correct, through learning, a command pressure of the lock-up clutch used in the packing control based on a packing completion time required from the start of the packing control until the packing completion state is reached; It contains A vehicle control device characterized in that, when the engine is started or stopped while the packing learning is being performed and the elapsed time from the start of the packing control is longer than the target value of the packing completion time, the learning control unit determines the time when the engine is started or stopped as the time when the packing completion state is reached, and corrects the command pressure of the lock-up clutch to be used for the next packing control to the pressure increase side.

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