Vehicle control device

Abstract

To curb generation of a shock due to abrupt engagement of a lock-up clutch while preventing degradation of energy efficiency when a vehicle travels with drive force output from an engine and an electric motor.SOLUTION: When drive force is output from an engine and an electric motor, a lock-up clutch control section makes an increment in torque capacity of the lock-up clutch with respect to a difference between an actual slip amount and a target slip amount due to feedback control in slip control of the lock-up clutch smaller than the same when the drive force is output only from either the engine or the electric motor. Thus, a vehicle control device can prevent the torque capacity of the lock-up clutch from becoming excessively large without stopping the slip control even when the difference between the actual slip amount and the target slip amount is increased. Accordingly, the vehicle control device can curb generation of a shock due to abrupt engagement of the lock-up clutch while preventing degradation of energy efficiency when the vehicle travels with drive force output from the engine and the electric motor.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle that is provided with a hydrodynamic power transmission with a direct-coupled clutch downstream of a driving force source including an engine and an electric motor. [Background technology]

[0002] There is a well-known control device for a vehicle that includes a driving force source and a fluid-type power transmission that has a direct-coupled clutch that couples an input rotating member and an output rotating member and transmits driving force from the driving force source from the input rotating member to the output rotating member via a fluid. For example, there is a control device for an automatic transmission described in Patent Document 1. Patent Document 1 discloses that the control device performs slip control of the lockup clutch, which adjusts the fastening force of the lockup clutch as a direct-coupled clutch by feedback control so that the lockup clutch is in a predetermined slip state, and that when the speed ratio of a torque converter as a fluid-type power transmission becomes larger than a predetermined value during the execution of the slip control of the lockup clutch, the slip control of the lockup clutch is prohibited and the lockup clutch is shifted to a released state, thereby preventing the occurrence of a large shock due to sudden engagement of the lockup clutch when shifting to an acceleration state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-326905 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle equipped with an engine and an electric motor as driving power sources, when driving with driving power output from the engine and the electric motor, the differential rotation of the hydrodynamic power transmission tends to be larger during slip control of the direct-coupled clutch than when driving with driving power output only from the engine or when driving with driving power output only from the electric motor, so if the slip control is not stopped, shock caused by sudden engagement of the direct-coupled clutch is significant. However, stopping the slip control to avoid sudden engagement of the direct-coupled clutch may result in a deterioration of energy efficiency.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that can suppress the deterioration of energy efficiency while suppressing the occurrence of shock due to sudden engagement of the direct-connection clutch when driving force is output from the engine and electric motor. [Means for solving the problem]

[0006] The gist of a first invention is a control device for a vehicle including: (a) an engine and an electric motor as driving force sources; and a fluid-type power transmission device having a direct-coupled clutch connecting an input rotating member and an output rotating member, and transmitting driving force from the driving force source from the input rotating member to the output rotating member via a fluid, the control device including: (b) a direct-coupled clutch control unit that performs slip control of the direct-coupled clutch, correcting a torque capacity of the direct-coupled clutch by feedback control so that an actual value of a slip amount of the direct-coupled clutch, which is a rotational speed difference between the input rotating member and the output rotating member, becomes a target value; and (c) a hybrid control unit that performs engine running in which driving force is output from at least the engine of the driving force sources, and motor running in which driving force is output only from the electric motor of the driving force sources, and (d) the direct-coupled clutch control unit: When an accelerator increase operation is performed during execution of an acceleration slip control executed during running with the accelerator on among the slip controls,When driving force is also output from the electric motor during engine running, the increase in the torque capacity of the direct-connection clutch relative to the difference between the actual value and the target value due to the feedback control is made smaller compared to when driving force is output only from the engine during engine running and when motor running is performed. Effect of the Invention

[0007] According to the first aspect of the present invention, When the accelerator pedal is increased during acceleration slip control, When driving force is output from the engine and the electric motor, the increase in torque capacity of the direct-coupled clutch relative to the difference between the actual and target slip amount due to feedback control in the slip control of the direct-coupled clutch is made smaller than when driving force is output only from the engine and when driving force is output only from the electric motor, so that the slip control is not stopped and an excessive torque capacity of the direct-coupled clutch is suppressed even if the difference between the actual and target slip amount becomes large. Therefore, when driving force is output from the engine and the electric motor, it is possible to suppress the occurrence of shock due to sudden engagement of the direct-coupled clutch while suppressing deterioration of energy efficiency. [Brief description 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 a control system for various controls in the vehicle. [Diagram 2] This is a flowchart explaining the main control operations of the electronic control device, and is a flowchart explaining the control operations for suppressing deterioration of energy efficiency while suppressing the occurrence of shock due to sudden engagement of the LU clutch when driving by outputting driving force from the engine and electric motor. [Diagram 3] 3 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 2 is executed. FIG. [Figure 4] FIG. 11 is a time chart showing a case where lock-up control is executed while the engine is running, which is an example of a reference example different from the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0010] Fig. 1 is a diagram illustrating a 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 system 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, which are driving power sources for traveling. The vehicle 10 also has driving wheels 14 and a power transmission device 16 provided in a power transmission path between the engine 12 and the driving wheels 14.

[0011] The engine 12 is a known internal combustion engine such as a gasoline engine, a diesel engine, etc. An engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, etc., provided in the vehicle 10 is controlled by an electronic control device 90 described later, whereby an engine torque Te, which is an output torque of the engine 12, is controlled.

[0012] 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 electric power from mechanical power, and is a so-called motor generator. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The battery 54 is an electricity storage device that supplies and receives electric power to the electric motor MG. The electric motor MG controls the MG torque Tm, which is the output torque of the electric motor MG, by controlling the inverter 52 by an electronic control device 90 described later. For example, when the rotation direction of the electric motor MG is a positive rotation that is the same as the rotation direction when the engine 12 is in operation, the MG torque Tm is a powering torque when it is a positive torque on the acceleration side, and a regenerative torque when it is a negative torque on the deceleration side. The electric power also means electric energy when there is no particular distinction. The power also means torque and force when there is no particular distinction.

[0013] The power transmission device 16 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, and the like, in a case 18 that 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 that 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 capable of transmitting power. In other words, the electric motor MG is connected to a power transmission path between the K0 clutch 20 and the torque converter 22 so as to be capable of transmitting power. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 so as to be capable of transmitting power without passing through the K0 clutch 20.

[0015] The torque converter 22 includes a pump wheel 22a connected to the motor connecting shaft 36, and a turbine wheel 22b connected to a transmission input shaft 38 that is an input rotating member of the automatic transmission 24. The pump wheel 22a is connected to the engine 12 via the K0 clutch 20, and is also directly connected to the electric motor MG. The pump wheel 22a is an input member of the torque converter 22, and the turbine wheel 22b is an output member of the torque converter 22. The motor connecting shaft 36 is also an input rotating member of the torque converter 22. The transmission input shaft 38 is also an output rotating member of the torque converter 22 that is formed integrally with a turbine shaft that is rotationally driven by the turbine wheel 22b. The torque converter 22 is a fluid-type power transmission device that transmits driving force from each of the driving force sources (engine 12, electric motor MG) from the motor connecting shaft 36 to the transmission input shaft 38 via a 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 clutch that connects input and output rotating members of the torque converter 22, that is, a known lock-up clutch.

[0016] The LU clutch 40 is a hydraulic friction engagement device constituted by, for example, a multi-plate or single-plate clutch. The LU clutch 40 has its operating state, i.e., its control state, changed by changing the LU torque Tlu, which is the torque capacity of the LU clutch 40, by the LU hydraulic pressure PRlu, which is a regulated hydraulic pressure supplied from a hydraulic control circuit 56 provided in the vehicle 10. The control states of the LU clutch 40 include a fully released state in which the LU clutch 40 is released, a slip state in which the LU clutch 40 is engaged with slipping, and a fully engaged state in which the LU clutch 40 is engaged. When the LU clutch 40 is in the fully released state, the torque converter 22 is in a torque converter state in which a torque amplification effect is obtained. When the LU clutch 40 is in the fully engaged state, the torque converter 22 is in a lock-up state in which the pump impeller 22a and the turbine impeller 22b are rotated together.

[0017] The automatic transmission 24 is a known planetary gear type automatic transmission including, for example, one or more planetary gear devices (not shown) and a plurality of engagement devices CB. The engagement devices CB are, for example, known hydraulic friction engagement devices. The engagement devices CB have their respective torque capacities, or CB torque Tcb, changed by the CB hydraulic pressure PRcb, or regulated hydraulic pressure, supplied from a hydraulic control circuit 56, thereby switching the control state, such as an engaged state or a released state.

[0018] The automatic transmission 24 is a stepped transmission in which one of a plurality of gear stages (also called gear stages) with different speed ratios (also called gear ratios) γat (=AT input rotation speed Ni / AT output rotation speed No) is formed by engaging one of the engagement devices CB. The automatic transmission 24 switches between gear stages formed according to the accelerator operation of the driver (=operator) and the vehicle speed V by an electronic control device 90 described later. 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 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 expressed by 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 constituted by, for example, a multi-plate or single-plate clutch. The K0 clutch 20 switches between control states such as an engaged state and a released state by changing the torque capacity of the K0 clutch 20, that is, the K0 torque Tk0, by the K0 oil pressure PRk0, that is, the regulated oil pressure supplied from the hydraulic control circuit 56.

[0020] In the vehicle 10, when the K0 clutch 20 is in an engaged state, the engine 12 and the torque converter 22 are connected to each other so as to transmit power. On the other hand, when the K0 clutch 20 is in a disengaged state, power transmission between the engine 12 and the torque converter 22 is interrupted. 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 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 driving 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. Moreover, the power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the driving 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, regardless of the control state of the K0 clutch 20.

[0022] The vehicle 10 includes the MOP 58, which is a mechanical oil pump, the EOP 60, which is an electric oil pump, and a pump motor 62. The MOP 58 is connected to the pump impeller 22a, and is rotated and driven by a driving force source (the engine 12, the electric motor MG) 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 rotating and driving the EOP 60. The EOP 60 is rotated and driven by the pump motor 62 to discharge hydraulic oil OIL. The hydraulic oil OIL discharged by the MOP 58 and the EOP 60 is supplied to a hydraulic control circuit 56. The hydraulic control circuit 56 supplies the CB hydraulic pressure PRcb, the K0 hydraulic pressure PRk0, the LU hydraulic pressure PRlu, and the like, which are adjusted based on the hydraulic oil OIL discharged by the MOP 58 and / or the EOP 60.

[0023] The vehicle 10 further includes an electronic control device 90 including 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, and the like, and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 90 includes computers for engine control, electric motor control, hydraulic control, and the like as necessary.

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

[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 Sbc 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 (e.g., the engine control device 50, the inverter 52, the hydraulic control circuit 56, the pump motor 62, etc.) provided in the vehicle 10.

[0026] In order to realize various controls in the vehicle 10, the electronic control device 90 is equipped with a hybrid control means, i.e., a hybrid control unit 92, and a hydraulic control means, i.e., a hydraulic control unit 94.

[0027] The hybrid control unit 92 includes a function as an engine control means, i.e., an engine control unit 92a, that controls the operation of the engine 12, and a function as an electric motor control means, i.e., an electric motor control unit 92b, that controls the operation of the electric motor MG via the inverter 52, and performs hybrid drive control using the engine 12 and the electric motor MG, etc., using these control functions.

[0028] The hybrid control unit 92 calculates the driving demand amount of 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 driving demand amount map is a relationship that is experimentally or design-wise determined and stored in advance, that is, a predetermined relationship. The driving demand amount is, for example, a required driving torque Trdem at the driving wheels 14. In other words, the required driving torque Trdem [Nm] is the required driving power Prdem [W] at the vehicle speed V at that time. The driving demand amount can also be the required driving force Frdem [N] at the driving wheels 14, the required AT output torque at the transmission output shaft 26, or the like. In calculating the driving demand amount, the AT output rotation speed No, or the like, can be used instead of the vehicle speed V.

[0029] The hybrid control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the electric motor MG so as to realize the required driving power Prdem, taking into consideration 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, etc. The engine control command signal Se is, for example, a command value for 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 rotation speed Nm at that time.

[0030] The chargeable power Win of the battery 54 is the maximum power that can be input, which specifies the limit on the input power of the battery 54, and indicates the input limit of the battery 54. The dischargeable power Wout of the battery 54 is the maximum power that can be output, which specifies the limit on the output power of the battery 54, and indicates the output limit of the battery 54. The chargeable power Win and dischargeable power Wout of the battery 54 are calculated by the electronic control device 90, for example, based on the battery temperature THbat and the state of charge value SOC [%] of the battery 54. The state of charge value SOC of the battery 54 is a value indicating the state of charge corresponding to the amount of charge of the battery 54, and is calculated by the electronic control device 90, for example, based on the battery charge / discharge current Ibat and the battery voltage Vbat.

[0031] When the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the hybrid control unit 92 sets the drive mode to the motor drive (=EV drive) mode. In the EV drive mode, the hybrid control unit 92 performs EV drive by outputting drive force only from the electric motor MG among the drive power sources (engine 12, electric motor MG) when the K0 clutch 20 is in the disengaged state. On the other hand, when the required drive torque Trdem cannot be satisfied without using at least the output of the engine 12, the hybrid control unit 92 sets the drive mode to the engine drive mode, i.e., hybrid drive (=HV drive) mode. In the HV drive mode, the hybrid control unit 92 performs engine drive by outputting drive force only from the engine 12 among the drive power sources (engine 12, electric motor MG) when the K0 clutch 20 is in the engaged state, i.e., HV drive. On the other hand, even if the required driving torque Trdem can be satisfied only by the output of the electric motor MG, the hybrid control unit 92 establishes the HV driving mode when the state of charge value SOC of the battery 54 falls below a predetermined engine start threshold value or when warming up of the engine 12 or the like is required. The engine start threshold value is a predetermined threshold value for determining that the state of charge value SOC is at a value at which the engine 12 needs to be forcibly started to charge the battery 54. In this way, the hybrid control unit 92 switches between the EV driving mode and the HV driving mode by automatically stopping the engine 12 during HV driving, restarting the engine 12 after the engine stop, or starting the engine 12 during EV driving, based on the required driving torque Trdem, etc.

[0032] The hydraulic control unit 94 includes a function as a K0 clutch control means, i.e., a K0 clutch control unit 94a, a function as a gear shift control means, i.e., a gear shift control unit 94b, and a function as an LU clutch control means, i.e., an LU clutch control unit 94c, and performs K0 clutch control, gear shift control, LU clutch control, etc. by means of these control functions.

[0033] The K0 clutch control unit 94a outputs a K0 hydraulic control command signal Sk0 to the hydraulic control circuit 56 to control the K0 clutch 20 from the released state toward the engaged state so as to obtain a K0 torque Tk0 for transmitting a torque required for cranking the engine 12, which is a torque for increasing the engine rotation speed Ne, to the engine 12 side at the start of the engine 12. In this embodiment, the torque required for cranking the engine 12 is referred to as a required cranking torque Tcrn.

[0034] When the engine 12 is started, the motor control unit 92b outputs an MG control command signal Sm to the inverter 52 to control the motor MG so that the motor MG outputs the required cranking torque Tcrn, i.e., so that the MG torque Tm is increased by the required cranking torque Tcrn, in accordance with the switching of the K0 clutch 20 to the engaged state by the K0 clutch control unit 94a.

[0035] When starting the engine 12, the engine control unit 92a outputs an engine control command signal Se to the engine control device 50 to control the engine 12 so that the engine 12 begins operating by initiating fuel supply, engine ignition, etc., in conjunction with cranking of the engine 12 by the K0 clutch 20 and the electric motor MG.

[0036] When the engine 12 is stopped, the engine control section 92a outputs an engine control command signal Se to the engine control device 50 for controlling the engine 12 so that the engine 12 stops operating by stopping the fuel supply or the like.

[0037] When the engine 12 is stopped, the K0 clutch control unit 94a outputs a K0 hydraulic control command signal Sk0 to the hydraulic control circuit 56 for controlling the K0 clutch 20 from the engaged state toward the released state.

[0038] The shift control unit 94b judges whether or not the automatic transmission 24 should be shifted by 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 to execute shift control of the automatic transmission 24 as necessary. The shift map is a predetermined relationship having a shift line for judging whether or not the automatic transmission 24 should be shifted, on a two-dimensional coordinate system having, for example, vehicle speed V and required driving torque Trdem as variables. In the shift map, the AT output rotation speed No may be used instead of the vehicle speed V, and the required driving force Frdem, accelerator opening θacc, throttle valve opening θth, etc. may be used instead of the required driving torque Trdem. The same applies to a lock-up region diagram described later.

[0039] The LU clutch control unit 94c is a direct clutch control unit that controls the control state of the LU clutch 40. Specifically, the LU clutch control unit 94c judges 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 the LU hydraulic pressure PRlu that realizes the control state corresponding to the judged region. The lock-up region diagram is a predetermined relationship having a completely released region, i.e., a lock-up off region, a slip region, and a completely engaged region, i.e., a lock-up region, on a two-dimensional coordinate system with, for example, the vehicle speed V and the required drive torque Trdem as variables.

[0040] When the LU clutch control unit 94c determines that the vehicle is in the lock-up region, it executes lock-up control of the LU clutch 40, by setting the LU hydraulic pressure PRlu to obtain the LU torque Tlu capable of transmitting the input torque Tin to the LU clutch 40 and bringing the LU clutch 40 into a fully engaged state. The input torque Tin is the total torque of the engine torque Te and the MG torque Tm during HV driving, and is the MG torque Tm during EV driving. The LU torque Tlu capable of transmitting the input torque Tin is, for example, a torque value obtained by multiplying the input torque Tin by a safety factor (>1).

[0041] When the LU torque Tlu is small relative to the input torque Tin, slippage occurs in the LU clutch 40. When the LU clutch control unit 94c determines that the input torque Tin is in the slip region, it executes slip control of the LU clutch 40, setting the LU hydraulic pressure PRlu for realizing the target slip amount Nslpt, which is the target value of the slip amount Nslp of the LU clutch 40, for the input torque Tin, and putting the LU clutch 40 in a target slip state. The slip amount Nslp of the LU clutch 40 is the rotation speed difference (=Nm-Nt) between the electric motor connecting shaft 36 and the transmission input shaft 38. During HV 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, in a low vehicle speed region compared to the lockup region, and is a region for improving energy efficiency and drivability by putting the vehicle in a slip state in a region where it is difficult to execute lockup control. The slip region is also a region that is set in consideration of drivability, muffled noise, etc. (for example, NV (noise and vibration) performance).

[0042] During the execution of the slip control of the LU clutch 40, the LU clutch control unit 94c corrects the LU hydraulic pressure PRlu, i.e., the LU torque Tlu, by feedback control so that the actual slip amount Nslpr, which is the actual value of the slip amount Nslp of the LU clutch 40, becomes the target slip amount Nslpt, as shown in the following equation (1). In the following equation (1), "PRluff" is the feedforward LU hydraulic pressure as the feedforward amount of the LU hydraulic pressure PRlu, and "PRlufb" is the feedback LU hydraulic pressure as the feedback amount, which is the correction amount of the LU hydraulic pressure PRlu that corrects the feedforward LU hydraulic pressure PRluff. The LU clutch control unit 94c calculates the feedforward LU hydraulic pressure PRluff using a map or function in which values ​​corresponding to the input torque Tin and the target slip amount Nslpt are predetermined. The above map or function is predetermined so that, for example, the larger the input torque Tin, the larger the feedforward LU hydraulic pressure PRluff becomes. The LU clutch control unit 94c calculates the feedback LU hydraulic pressure PRlufb, for example, using the following equation (2). The following formula (2) is a predetermined feedback control formula having a proportional term (P component), an integral term (I component), and a differential term (D component). In the following formula (2), the first term on the right side is the proportional term, the second term on the right side is the integral term, and the third term on the right side is the differential term. "ΔNs" is the slip amount difference (=Nslpr-Nslpt) which is the difference between the actual slip amount Nslpr and the target slip amount Nslpt, "Kp" is a proportional constant (gain), "Ki" is an integral constant (gain), and "Kd" is a differential constant (gain).

[0043] PRlu = PRluff + PRlufb (1) PRlufb=Kp×ΔNs+Ki×∫(ΔNs)dt+Kd×d(ΔNs) / dt ···(2)

[0044] The slip control of the LU clutch 40 includes start slip control and steady slip control. The start slip control is a control for putting the LU clutch 40 into a slip state when the vehicle starts with the accelerator on, for example, so that the engine rotation speed Ne does not increase. The steady slip control is a control for putting the LU clutch 40 into a slip state in a region where it is difficult to put the LU clutch 40 into a fully engaged state during steady running other than when the vehicle starts, for example, so that the region of lock-up control is substantially expanded. In the steady slip control, the control executed during constant speed running or accelerating running with the accelerator on may be called acceleration slip control, and the control executed during deceleration running with the accelerator off may be called deceleration slip control.

[0045] By the way, assuming a situation in which the input torque Tin is increased by an increase in the required drive torque Trdem due to an operation such as further depression of the accelerator pedal while the acceleration slip control of the LU clutch 40 is being executed, in engine running in which the drive force is also output from the electric motor MG, the increase gradient of the input torque Tin is made larger than in engine running in which the drive force is output only from the engine 12 and in EV running, so that the LU oil pressure PRlu in the acceleration slip control, i.e., the LU torque Tlu, cannot follow the input torque Tin due to a response delay of the actual oil pressure, and the actual slip amount Nslpr tends to be large. Therefore, in the acceleration slip control, the feedback amount, i.e., the feedback LU oil pressure PRlufb, is increased with an increase in the slip amount difference ΔNs, and by the time the actual oil pressure follows, the LU torque Tlu becomes excessive with respect to the input torque Tin, and the LU clutch 40 cannot maintain the slip state and is suddenly engaged, which may cause a shock. On the other hand, in the above-mentioned assumed situation, in engine running in which driving force is also output from the electric motor MG, it is conceivable to temporarily stop the acceleration slip control in order to avoid sudden engagement of the LU clutch 40. However, stopping the acceleration slip control may result in a deterioration in energy efficiency. Or, from another perspective, if the acceleration slip control is stopped and the LU clutch 40 is put into a released state or a state close to the released state, it may take time to put the LU clutch 40 into the desired slip state, and the responsiveness of the driving force to the accelerator operation by the driver may decrease.

[0046] Therefore, when driving force is also output from the electric motor MG during engine running, the LU clutch control unit 94c reduces the increase in the LU oil pressure PRlu, i.e., the LU torque Tlu, relative to the slip amount difference ΔNs, due to feedback control in the slip control of the LU clutch 40, compared to when driving force is output only from the engine 12 during engine running and when EV running is performed.

[0047] Specifically, the LU clutch control unit 94c determines whether or not the acceleration slip control is being executed.

[0048] When the LU clutch control unit 94c determines that the acceleration slip control is being executed, the hybrid control unit 92 determines whether the driver has increased the required driving torque Trdem, for example, whether the driver has further depressed the accelerator based on the accelerator opening θacc. When the LU clutch control unit 94c determines that the acceleration slip control is being executed, the hybrid control unit 92 determines whether the driving force is also being output from the electric motor MG during engine running, that is, whether engine running in which the driving force is assisted by the electric motor MG is being executed.

[0049] When it is determined that the acceleration slip control is being performed, the LU clutch control unit 94c continues the acceleration slip control while maintaining the feedback LU hydraulic pressure PRlufb at the time when it is determined that the accelerator pedal has been depressed further by the hybrid control unit 92 and that the engine running in which the driving force is assisted by the electric motor MG is being performed, for example. Maintaining the feedback LU hydraulic pressure PRlufb means maintaining the feedback LU hydraulic pressure PRlufb accumulated up to that point, regardless of the slip amount difference ΔNs. In other words, maintaining the feedback LU hydraulic pressure PRlufb means performing feedback control without updating the feedback LU hydraulic pressure PRlufb by regarding the actual slip amount Nslpr as being maintained at the target slip amount Nslpt, that is, by regarding the slip amount difference ΔNs as zero even if there is a slip amount difference ΔNs. As a result, the LU oil pressure PRlu after the input torque Tin starts to increase is increased by the amount of increase in the feedforward LU oil pressure PRluff that corresponds to the increase in the input torque Tin, and the increase in the LU oil pressure PRlu is suppressed compared to normal acceleration slip control in which the feedback LU oil pressure PRlufb is updated according to the slip amount difference ΔNs. Note that in the above-mentioned control, the slip amount difference ΔNs is considered to be zero, but instead of this, for example, the slip amount difference ΔNs may be made smaller at a constant rate compared to normal acceleration slip control, or an upper limit may be set for the slip amount difference ΔNs, or each gain in the feedback control formula may be made smaller compared to normal acceleration slip control.

[0050] The LU clutch control unit 94c determines whether the actual slip amount Nslpr coincides with the target slip amount Nslpt during acceleration slip control with the feedback LU hydraulic pressure PRlufb maintained. Alternatively, the LU clutch control unit 94c may determine whether the actual slip amount Nslpr has approached the target slip amount Nslpt to such an extent that it can be determined that the actual slip amount Nslpr coincides with the target slip amount Nslpt.

[0051] When the LU clutch control unit 94c determines that the actual slip amount Nslpr coincides with the target slip amount Nslpt while acceleration slip control is being performed while maintaining the feedback LU hydraulic pressure PRlufb, the LU clutch control unit 94c returns to normal acceleration slip control.

[0052] Fig. 2 is a flowchart for explaining the main part of the control operation of the electronic control device 90, which is for suppressing the deterioration of energy efficiency while driving the vehicle by outputting driving force from the engine 12 and the electric motor MG and suppressing the occurrence of shock due to sudden engagement of the LU clutch 40, and is executed, for example, repeatedly. 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.

[0053] In FIG. 2, first, in step S10 (hereinafter, step will be omitted) corresponding to the function of the LU clutch control unit 94c, it is determined whether or not the acceleration slip control is being executed. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, it is determined in S20 corresponding to the function of the hybrid control unit 92 whether or not the accelerator pedal has been depressed further. If the determination in S20 is negative, this routine is terminated. If the determination in S20 is positive, it is determined in S30 corresponding to the function of the hybrid control unit 92 whether or not the engine running in which the driving force is assisted by the electric motor MG is being executed. If the determination in S30 is negative, this routine is terminated. If the determination in S30 is positive, in S40 corresponding to the function of the LU clutch control unit 94c, the acceleration slip control is continued while maintaining the feedback LU hydraulic pressure PRlufb at the time when it is determined that the accelerator pedal has been depressed further. Next, in S50, which corresponds to the function of the LU clutch control section 94c, it is determined whether the actual slip amount Nslpr coincides with the target slip amount Nslpt. If the determination in S50 is negative, the process returns to S40. If the determination in S50 is positive, the process returns to normal acceleration slip control in S60, which corresponds to the function of the LU clutch control section 94c.

[0054] FIG. 3 is a diagram showing an example of a case where slip control during acceleration of the LU clutch 40 is executed during engine running. In FIG. 3, time t1 indicates the time when the accelerator pedal is depressed further during engine running. This accelerator pedal depression operation assists the driving force by the electric motor MG, and the input torque Tin is increased at a large gradient compared to engine running in which the driving force is output only from the engine 12, or compared to EV running (see time t1 and after). In the comparative example shown by the broken line, the LU hydraulic pressure PRlu cannot follow the increase in the input torque Tin due to a response delay of the actual hydraulic pressure, so the slip amount difference ΔNs is increased, and the feedback LU hydraulic pressure PRlufb is increased. Then, by the time the LU hydraulic pressure PRlu follows the input torque Tin, the LU hydraulic pressure PRlu, i.e., the LU torque Tlu, becomes excessive with respect to the input torque Tin (see part A), and a shock occurs due to the sudden engagement of the LU clutch 40. In contrast, in the present embodiment shown by the solid line, after time t1, the acceleration slip control continues with the feedback LU oil pressure PRlufb at time t1 being maintained, so the increase in the LU oil pressure PRlu is suppressed compared to the comparative example (see part B). As a result, although the slip amount difference ΔNs is increased compared to the comparative example, the acceleration slip control is not stopped, so the LU clutch 40 is smoothly returned to the target slip state and sudden engagement of the LU clutch 40 is avoided. When the LU clutch 40 is returned to the target slip state, normal acceleration slip control is restored (see time t2). The two-dot chain line in the figure indicates the target value of the engine rotation speed Ne for achieving the actual slip amount Nslpr that coincides with the target slip amount Nslpt.

[0055] Here, a case where the input torque Tin is increased by further depressing the accelerator while the lock-up control of the LU clutch 40 is being executed will be described as a reference example of this embodiment.

[0056] FIG. 4 is a time chart when lock-up control is executed during engine running, and is a diagram showing an example of a reference example different from this embodiment. In FIG. 4, time t1b indicates the time when the accelerator pedal is depressed further during engine running. This accelerator pedal depression operation increases the input torque Tin at a large gradient, as in FIG. 3 (see time t1b and after). In the comparative example shown by the broken line, an LU torque Tlu is generated that is equal to the input torque Tin multiplied by a safety factor (>1) equivalent to that of engine running in which driving force is output only from the engine 12, but the LU hydraulic pressure PRlu cannot follow the increase in the input torque Tin due to a response delay of the actual hydraulic pressure, so the LU clutch 40 is put into a slip state, and the LU hydraulic pressure PRlu follows the input torque Tin (see part C), causing a shock due to sudden engagement of the LU clutch 40. In contrast to this, in the reference example shown by the solid line, in preparation for an increase in input torque Tin due to further accelerator depression, an LU torque Tlu is generated from before time t1b, the magnitude of which is calculated by multiplying the input torque Tin by a safety factor that is larger than that in engine running in which driving force is output only from the engine 12. As a result, after time t1b, an LU torque Tlu that exceeds the input torque Tin is generated (see part D) even if there is a response delay in the actual hydraulic pressure, so the LU clutch 40 is not put into a slip state, that is, the fully engaged state of the LU clutch 40 is maintained, and re-engagement of the LU clutch 40 does not occur.

[0057] As described above, according to this embodiment, when driving force is output from the engine 12 and the electric motor MG, the increase in the LU torque Tlu relative to the slip amount difference ΔNs due to feedback control in the slip control of the LU clutch 40 is made smaller than when driving force is output only from the engine 12 and when driving force is output only from the electric motor MG, so that the slip control is not stopped and an excess of the LU torque Tlu is suppressed even if the slip amount difference ΔNs becomes large. Therefore, when driving force is output from the engine 12 and the electric motor MG and the vehicle is traveling, it is possible to suppress the occurrence of shock due to sudden engagement of the LU clutch 40 while suppressing deterioration of energy efficiency.

[0058] Or, from another perspective, since the slip control during acceleration is not stopped and the LU clutch 40 is not put into a released state or a state close to the released state, the LU clutch 40 can be smoothly returned to the desired slip state, thereby suppressing the occurrence of shock due to sudden engagement of the LU clutch 40 while suppressing a decrease in acceleration responsiveness to accelerator operation.

[0059] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0060] For example, in the above embodiment, a planetary gear type automatic transmission is exemplified as the automatic transmission 24, but the present invention is not limited to this embodiment. The automatic transmission 24 may be a synchronous mesh type parallel two-shaft automatic transmission including a known DCT (Dual Clutch Transmission), a known belt type continuously variable transmission, or the like. In addition, in the above embodiment, the torque converter 22 is used as the fluid type power transmission device, but the present invention is not limited to this embodiment. For example, instead of the torque converter 22, other fluid type power transmission devices such as a fluid coupling without torque amplification may be used as the fluid type power transmission device. In short, the present invention can be applied to any vehicle equipped with an engine and an electric motor as a driving force source, and a fluid type power transmission device having a direct-coupled clutch that transmits driving force from the driving force source.

[0061] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0062] 10: Vehicle 12: Engine (power source) 22: Torque converter (fluid transmission device) 36: Motor connecting shaft (input rotating member of fluid transmission device) 38: Transmission input shaft (output rotating member of fluid transmission) 40: LU clutch (direct clutch) 90: Electronic control device (control device) 92: Hybrid control unit 94c: LU clutch control unit (direct clutch control unit) MG: Electric motor (driving force source)

Claims

[Claim 1] A control device for a vehicle including an engine and an electric motor as a driving force source, and a fluid type power transmission device having a direct-coupled clutch that couples an input rotary member and an output rotary member, and that transmits driving force from the driving force source from the input rotary member to the output rotary member via a fluid, comprising: a direct-coupled clutch control unit that performs slip control of the direct-coupled clutch by correcting a torque capacity of the direct-coupled clutch through feedback control so that an actual value of a slip amount of the direct-coupled clutch, which is a rotational speed difference between the input rotating member and the output rotating member, becomes a target value; a hybrid control unit that performs engine running in which the vehicle runs by outputting driving force from at least the engine among the driving force sources, and motor running in which the vehicle runs by outputting driving force only from the electric motor among the driving force sources; Contains The vehicle control device is characterized in that, when an accelerator increase operation is performed during execution of acceleration slip control, which is one of the slip controls and is executed when driving with the accelerator on, when driving force is also output from the electric motor during engine driving, the direct clutch control unit reduces the increase in torque capacity of the direct clutch relative to the difference between the actual value and the target value, which is achieved by the feedback control, compared to each of the cases when driving force is output only from the engine during engine driving and when the motor driving is performed.

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