JP2022112446A - Vehicle control device - Google Patents

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle having a hydrodynamic transmission with a direct coupling clutch downstream of a driving force source including an engine and an electric motor.

A hydraulic type that has a direct coupling clutch that connects a driving force source and an input rotating member and an output rotating member, and that transmits the driving force from the driving force source from the input rotating member to the output rotating member via a fluid. Control systems for vehicles with transmissions are well known. For example, a control device for an automatic transmission described in Patent Document 1 is one of them. In this patent document 1, slip control of the lockup clutch is performed to adjust the engagement force of the lockup clutch by feedback control so that the lockup clutch as a direct coupling clutch is in a predetermined slip state. During the execution of slip control, when the speed ratio of the torque converter as a hydrodynamic transmission device becomes greater than a predetermined value, the slip control of the lockup clutch is prohibited and the lockup clutch is shifted to the released state. It is disclosed to prevent occurrence of a large shock due to sudden engagement of a lockup clutch when shifting to an acceleration state.

JP-A-8-326905

By the way, in a vehicle provided with an engine and an electric motor as driving force sources, when the driving force is output from the engine and the electric motor, the driving force is output only from the engine, and when the driving force is output only from the electric motor. Compared to each of the two cases, the differential rotation of the hydrodynamic transmission tends to increase during the execution of the slip control of the direct coupling clutch. The occurrence of shock due to coalescence is conspicuous. However, if slip control is stopped to avoid sudden engagement of the direct coupling clutch, energy efficiency may deteriorate.

SUMMARY OF THE INVENTION The present invention has been made against the background of the above circumstances, and its object is to suppress the deterioration of the energy efficiency when driving by outputting the driving force from the engine and the electric motor, while suppressing the deterioration of the direct clutch. To provide a vehicle control device capable of suppressing the occurrence of a shock due to sudden engagement.

The gist of the first invention is (a) having an engine and an electric motor as driving force sources, and a direct coupling clutch that connects an input rotating member and an output rotating member, so that the driving force from the driving force source is provided. (b) rotation of the input rotary member and the output rotary member; (c) a direct coupling clutch control unit that performs slip control of the direct coupling clutch, correcting the torque capacity of the direct coupling clutch by feedback control so that the actual value of the slip amount of the direct coupling clutch, which is the speed difference, becomes a target value; Hybrid control for performing 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 clutch control unit outputs driving force only from the engine during engine running, and when driving force is also output from the electric motor during engine running. , and when the motor running is performed, the amount of increase in the torque capacity of the direct coupling clutch with respect to the difference between the actual value and the target value due to the feedback control is reduced.

According to the first aspect, when the driving force is output from the engine and the electric motor, compared to when the driving force is output only from the engine and when the driving force is output only from the electric motor, Since the increase in the torque capacity of the direct coupling clutch with respect to the difference between the actual value and the target value of the slip amount is reduced by the feedback control in the slip control of the direct coupling clutch, the actual slip amount can be adjusted without stopping the slip control. Excessive torque capacity of the direct clutch is suppressed even if the difference between the value and the target value increases. Therefore, when the vehicle travels by outputting the driving force from the engine and the electric motor, it is possible to suppress the deterioration of the energy efficiency and suppress the occurrence of the shock caused by the sudden engagement of the direct coupling clutch.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining a schematic configuration of a vehicle to which the present invention is applied, and is a diagram for explaining main parts of a control system and control functions for various controls in the vehicle; It is a flow chart explaining the main part of the control operation of the electronic control unit, suppressing the occurrence of shock due to sudden engagement of the LU clutch while suppressing the deterioration of energy efficiency when driving by outputting the driving force from the engine and the electric motor. 2 is a flow chart for explaining a control operation for carrying out; 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. FIG. 5 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 the present embodiment.

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

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

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

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

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

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

The torque converter 22 includes a pump impeller 22 a connected to an electric motor connecting shaft 36 and a turbine impeller 22 b connected to a transmission input shaft 38 which is an input rotating member of the automatic transmission 24 . The pump impeller 22a is connected to the engine 12 via the K0 clutch 20 and directly connected to the electric motor MG. Pump impeller 22 a is an input member of torque converter 22 , and turbine impeller 22 b is an output member of torque converter 22 . The electric 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 integrally formed with a turbine shaft rotationally driven by the turbine impeller 22b. Torque converter 22 is a hydrodynamic transmission device that transmits driving force from each of the driving force sources (engine 12, electric motor MG) from electric motor coupling shaft 36 to transmission input shaft 38 via fluid. The torque converter 22 includes an LU clutch 40 that connects the pump impeller 22 a and the turbine impeller 22 b , that is, connects the electric motor connection shaft 36 and the transmission input shaft 38 . The LU clutch 40 is a direct coupling clutch that connects the input and output rotating members of the torque converter 22, that is, a known lockup clutch.

The LU clutch 40 is a hydraulic friction engagement device configured by, for example, a multi-plate or single-plate clutch. The LU clutch 40 is operated by changing the LU torque Tlu, which is the torque capacity of the LU clutch 40, by the LU hydraulic pressure PRlu, which is the regulated hydraulic pressure supplied from the hydraulic control circuit 56 provided in the vehicle 10. That is, the control state is switched. The control state of the LU clutch 40 includes a completely released state in which the LU clutch 40 is released, a slip state in which the LU clutch 40 is engaged with slippage, and a state in which the LU clutch 40 is engaged. There is a state, fully engaged. By bringing the LU clutch 40 into a completely released state, the torque converter 22 is brought into a torque converter state in which a torque amplifying action can be obtained. Further, the torque converter 22 is brought into a lockup state in which the pump impeller 22a and the turbine impeller 22b are integrally rotated by the LU clutch 40 being fully engaged.

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

In the automatic transmission 24, the gear ratio (also referred to as gear ratio) γat (=AT input rotation speed Ni/AT output rotation speed No) is established by engaging any one of the engagement devices CB. is a stepped transmission in which one of a plurality of gear stages (also referred to as gear stages) is formed. The automatic transmission 24 switches between gear stages according to the driver's accelerator operation, the vehicle speed V, and the like, by an electronic control unit 90, which will be described later. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38 and the input rotation speed of the automatic transmission 24 . The AT input rotation speed Ni has the same value as the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22 . The AT input rotation speed Ni can be represented by the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26 and the output rotation speed of the automatic transmission 24 .

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

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

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

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

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

The electronic control unit 90 includes various sensors provided in the vehicle 10 (for example, the engine rotation speed sensor 70, the turbine rotation speed sensor 72, the output rotation speed sensor 74, the MG rotation speed sensor 76, the accelerator opening sensor 78, the throttle valve Various signals based on detection values by the opening sensor 80, the brake switch 82, the battery sensor 84, the oil temperature sensor 86, etc. (e.g., the engine rotation speed Ne, which is the rotation speed of the engine 12, and the AT input rotation speed Ni) Turbine rotation speed Nt, AT output rotation speed No corresponding to vehicle speed V, MG rotation speed Nm, which is the rotation speed of electric motor MG, and accelerator opening θacc, which is the amount of accelerator operation by the driver representing the magnitude of acceleration operation by the driver. , the throttle valve opening θth which is the opening of the electronic throttle valve, the brake-on signal Bon which is a signal indicating that the brake pedal for operating the wheel brake is being operated by the driver, the battery temperature THbat of the battery 54, and A battery charging/discharging current Ibat, a battery voltage Vbat, a working oil temperature THoil which is the temperature of the working oil OIL in the hydraulic control circuit 56, etc.) are respectively supplied.

From the electronic control device 90, various command signals (for example, engine Control command signal Se, MG control command signal Sm for controlling the electric motor MG, CB hydraulic control command signal Scb for controlling the engagement device CB, K0 hydraulic control command signals Sk0 and LU for controlling the K0 clutch 20 LU oil pressure control command signal Slu for controlling the clutch 40, EOP control command signal Seop for controlling the EOP 60, etc.) are respectively output.

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

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

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

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

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

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

The hydraulic control unit 94 functions as K0 clutch control means, that is, a K0 clutch control unit 94a, as shift control means, that is, as a shift control unit 94b, and as LU clutch control means, that is, as an LU clutch control unit 94c. K0 clutch control, shift control, LU clutch control, etc. are executed by these control functions.

When starting the engine 12, the K0 clutch control unit 94a is released so as to obtain the K0 torque Tk0 for transmitting the torque required for cranking the engine 12 to the engine 12 side, which is the torque for increasing the engine rotation speed Ne. A K0 hydraulic control command signal Sk0 is output to the hydraulic control circuit 56 to control the K0 clutch 20 in the state toward the engaged state. In this embodiment, the torque required for cranking the engine 12 is referred to as required cranking torque Tcrn.

When the engine 12 is started, the electric motor control section 92b controls the electric motor MG to output the required cranking torque Tcrn, that is, the MG torque Tm is increased by the necessary cranking torque Tcrn, the MG control command signal Sm for controlling the electric motor MG is output to the inverter 52 .

When starting the engine 12, the engine control unit 92a controls the engine 12 so that the engine 12 starts operating by starting fuel supply, engine ignition, etc., in conjunction with cranking of the engine 12 by the K0 clutch 20 and the electric motor MG. An engine control command signal Se for control is output to the engine control device 50 .

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

When the engine 12 is stopped, the K0 clutch control section 94a outputs to the hydraulic control circuit 56 a K0 hydraulic control command signal Sk0 for controlling the engaged K0 clutch 20 toward the disengaged state.

The shift control unit 94b performs shift determination of the automatic transmission 24 using, for example, a shift map having a predetermined relationship, and outputs a CB hydraulic control command signal for executing shift control of the automatic transmission 24 as necessary. Scb is output to the hydraulic control circuit 56 . The shift map is a predetermined relationship having a shift line for judging the shift of the automatic transmission 24 on two-dimensional coordinates having, for example, the vehicle speed V and the required drive torque Trdem as variables. In the shift map, the AT output rotational speed No may be used instead of the vehicle speed V, and the required driving force Frdem, the accelerator opening θacc, the throttle valve opening θth, etc. may be used instead of the required driving torque Trdem. can be The same applies to a lockup area diagram, which will be described later.

The LU clutch control section 94c is a direct coupling clutch control section that controls the control state of the LU clutch 40 . Specifically, the LU clutch control unit 94c determines the control region using, for example, a lockup region diagram that is a predetermined relationship, and the LU hydraulic pressure that realizes the control state corresponding to the determined region. An LU hydraulic control command signal Slu for supplying PRlu to the LU clutch 40 is output to the hydraulic control circuit 56 . The lockup area diagram is a predetermined lockup area having a complete release area, i.e., lockup off area, a slip area, and a complete engagement area, i.e., lockup area, on two-dimensional coordinates having, for example, vehicle speed V and required drive torque Trdem as variables. relationship.

When the LU clutch control unit 94c determines that the lockup region is reached, the LU clutch control unit 94c sets the LU oil pressure PRlu for obtaining the LU torque Tlu capable of transmitting the input torque Tin to the LU clutch 40, and the LU clutch 40 is operated. Lockup control of the LU clutch 40 is executed to bring it into the fully engaged state. The input torque Tin is the total torque of the engine torque Te and the MG torque Tm during HV running, and is the MG torque Tm during EV running. The LU torque Tlu that can transmit the input torque Tin is, for example, a torque value obtained by multiplying the input torque Tin by a safety factor (>1).

If the LU torque Tlu is smaller than the input torque Tin, the LU clutch 40 will slip. When the LU clutch control unit 94c determines that it is in the slip region, 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, with respect to the input torque Tin. Slip control of the LU clutch 40 is executed to set the LU clutch 40 to the target slip state. The slip amount Nslp of the LU clutch 40 is the rotational speed difference between the electric motor connecting shaft 36 and the transmission input shaft 38 (=Nm-Nt). During HV travel, 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 in a region where lockup control is difficult to execute, the slip state is used to improve energy efficiency and drivability. It is an area for planning. The slip region is also a region that is set in consideration of drivability, muffled sound, etc. (for example, NV (noise/vibration) performance).

During execution of the slip control of the LU clutch 40, the LU clutch control unit 94c changes the actual slip amount Nslpr, which is the actual value of the slip amount Nslp of the LU clutch 40, to the target slip amount Nslpt as shown in the following equation (1). The LU oil pressure PRlu, that is, the LU torque Tlu is corrected by feedback control so that 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 correction amount of the LU hydraulic pressure PRlu that corrects the feedforward LU hydraulic pressure PRluff. Feedback LU oil pressure as a quantity. 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, for example. The above map or function is predetermined such that, for example, the larger the input torque Tin, the larger the value of the feedforward LU hydraulic pressure PRluff. The LU clutch control unit 94c calculates the feedback LU oil pressure PRlufb using, for example, the following equation (2). Equation (2) below is a predetermined feedback control equation having a proportional term (P component), an integral term (I component), and a differential term (D component). In the following equation (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) as the difference between the actual slip amount Nslpr and the target slip amount Nslpt, "Kp" is the proportional constant (gain), and "Ki" is the integral constant ( gain) and "Kd" is the differential constant (gain).

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

The slip control of the LU clutch 40 includes starting slip control and steady state slip control. The starting slip control is a control that puts the LU clutch 40 in a slipping state so that, for example, the engine rotation speed Ne does not rise when the vehicle is started with the accelerator on. The above-described steady-state slip control is a slip state in a region where it is difficult to fully engage the LU clutch 40 so that, for example, the lock-up control region is substantially expanded during steady running other than when the vehicle is started. control. In the steady-state slip control, the slip control during acceleration may be defined as the slip control during acceleration when the vehicle is traveling at a constant speed or during acceleration with the accelerator on, and the slip control during deceleration may be defined as the slip control during deceleration when the vehicle is decelerating when the accelerator is off. .

By the way, when it is assumed that the input torque Tin is increased due to an increase in the required driving torque Trdem due to an increase in the accelerator pedal operation or the like during the execution of the slip control during acceleration of the LU clutch 40, the driving force is also output from the electric motor MG. In engine running, the gradient of increase in input torque Tin is greater than in engine running, in which driving force is output only from the engine 12, and EV running. That is, the LU torque Tlu cannot follow the input torque Tin due to the response delay of the actual oil pressure, and the actual slip amount Nslpr tends to increase. Therefore, in acceleration slip control, the feedback amount, that is, the feedback LU oil pressure PRlufb is increased as the slip amount difference ΔNs increases, and when the actual oil pressure follows, the LU torque Tlu becomes excessive with respect to the input torque Tin. , there is a possibility that the LU clutch 40 cannot maintain the slipping state and is suddenly engaged, causing a shock. On the other hand, in the case of the assumed situation described above, during engine running in which driving force is also output from the electric motor MG, it is possible to temporarily stop slip control during acceleration in order to avoid sudden engagement of the LU clutch 40. Conceivable. However, stopping the slip control during acceleration may deteriorate the energy efficiency. Alternatively, from another point of view, when the acceleration slip control is stopped and the LU clutch 40 is put in a released state or a state close to the released state, it takes time to put the LU clutch 40 in the target slip state after that. , there is a possibility that the responsiveness of the driving force to the accelerator operation by the driver is lowered.

Therefore, the LU clutch control unit 94c is controlled when driving force is also output from the electric motor MG during engine running, when driving force is output only from the engine 12 during engine running, and when EV running is performed. , the increment of the LU hydraulic pressure PRlu, that is, the LU torque Tlu with respect to the slip amount difference ΔNs due to the feedback control in the slip control of the LU clutch 40 is made smaller.

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

When the LU clutch control unit 94c determines that slip control during acceleration is being executed, the hybrid control unit 92 determines whether or not the driver has increased the required driving torque Trdem. Based on, it is determined whether or not the driver has further stepped on the accelerator. Further, when the LU clutch control unit 94c determines that the slip control during acceleration is being executed, the hybrid control unit 92 determines whether or not the electric motor MG is also outputting driving force during engine running, that is, the electric motor A determination is made as to whether or not engine running is being executed in which the driving force is assisted by the MG.

When the LU clutch control unit 94c determines that slip control during acceleration is being executed, the hybrid control unit 92 determines that the driver has stepped on the accelerator further, and the electric motor MG assists the driving force. When it is determined that the engine running is being executed, the slip control during acceleration is continued while maintaining the feedback LU oil pressure PRlufb at the time when it is determined that the accelerator is further depressed. Maintaining the feedback LU oil pressure PRlufb means maintaining the accumulated feedback LU oil pressure PRlufb regardless of the slip amount difference ΔNs. In other words, maintaining the feedback LU oil pressure PRlufb means that the actual slip amount Nslpr is maintained at the target slip amount Nslpt. Therefore, feedback control is performed and the feedback LU oil pressure PRlufb is not updated. As a result, the LU oil pressure PRlu after the start of increasing the input torque Tin is increased by the increase in the feedforward LU oil pressure PRluff according to the increase in the input torque Tin, and the feedback LU oil pressure PRlufb is updated according to the slip amount difference ΔNs. An increase in the LU oil pressure PRlu is suppressed compared to normal slip control during acceleration. In the control described above, the slip amount difference ΔNs is assumed to be zero. An upper limit may be provided for ΔNs, or each gain in the feedback control formula may be made smaller than in normal slip control during acceleration.

The LU clutch control unit 94c determines whether or not the actual slip amount Nslpr matches the target slip amount Nslpt during execution of slip control during acceleration while maintaining the feedback LU oil pressure PRlufb. The LU clutch control section 94c may determine whether or not the actual slip amount Nslpr has approached the target slip amount Nslpt to the extent that it can be determined that the actual slip amount Nslpr has matched the target slip amount Nslpt.

When the LU clutch control unit 94c determines that the actual slip amount Nslpr matches the target slip amount Nslpt during the execution of slip control during acceleration while maintaining the feedback LU oil pressure PRlufb, normal slip during acceleration Return to control.

FIG. 2 is a flow chart for explaining the main part of the control operation of the electronic control unit 90. When traveling by outputting the driving force from the engine 12 and the electric motor MG, the LU clutch 40 is operated while suppressing the deterioration of the energy efficiency. 4 is a flowchart for explaining a control operation for suppressing the occurrence of shock due to sudden engagement, which is repeatedly executed, for example. FIG. 3 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 2 is executed.

In FIG. 2, first, in step S10 (hereinafter, the step is omitted) corresponding to the function of the LU clutch control section 94c, it is determined whether or not slip control during acceleration is being executed. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is affirmative, in S20 corresponding to the function of the hybrid control unit 92, it is determined whether or not the accelerator pedal operation has been performed. If the determination in S20 is negative, this routine is terminated. If the determination in S20 is affirmative, in S30 corresponding to the function of the hybrid control unit 92, it is determined 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 affirmative, in S40 corresponding to the function of the LU clutch control unit 94c, the acceleration slip control is performed while maintaining the feedback LU oil pressure PRlufb at the time when it is determined that the accelerator pedal is further depressed. is allowed to continue. Next, in S50 corresponding to the function of the LU clutch control section 94c, it is determined whether or not the actual slip amount Nslpr matches the target slip amount Nslpt. If the determination in S50 is negative, the process returns to S40. If the determination in S50 is affirmative, in S60 corresponding to the function of the LU clutch control section 94c, normal slip control during acceleration is restored.

FIG. 3 is a diagram showing an example in which 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 is further depressed during engine running. The driving force is assisted by the electric motor MG by further pressing the accelerator, and the input torque Tin is increased at a larger gradient than in the engine running in which the driving force is output only from the engine 12 or in the EV running. (see after t1). In the comparative example shown by the dashed line, the LU oil pressure PRlu cannot follow the increase in the input torque Tin due to the response delay of the actual oil pressure, and the slip amount difference ΔNs is increased, and the feedback LU oil pressure PRlufb is increased. Then, when the LU hydraulic pressure PRlu has followed the input torque Tin, the LU hydraulic pressure PRlu, that is, the LU torque Tlu becomes excessive with respect to the input torque Tin (see section A), and a shock occurs due to the sudden engagement of the LU clutch 40. is doing. On the other hand, in the present embodiment shown by the solid line, since the feedback LU oil pressure PRlufb at time t1 is maintained after time t1, the slip control during acceleration is continued. is suppressed (see section B). As a result, although the slip amount difference ΔNs is increased compared to the comparative example, the slip control during acceleration is not stopped, so the LU clutch 40 is smoothly returned to the target slip state, and the LU clutch 40 is rapidly released. Engagement is avoided. When the LU clutch 40 is returned to the target slip state, normal acceleration slip control is resumed (see time t2). The chain double-dashed line in the drawing indicates the target value of the engine rotation speed Ne for realizing the actual slip amount Nslpr that matches the target slip amount Nslpt.

Here, an example will be shown as a reference example of the present embodiment in the case where the input torque Tin is increased by an accelerator depression operation or the like while the lockup control of the LU clutch 40 is being executed.

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 the present embodiment. In FIG. 4, time t1b indicates the time when the accelerator pedal is further depressed during engine running. By this accelerator stepping operation, the input torque Tin is increased at a large gradient, as in FIG. 3 (see after time t1b). In the comparative example indicated by the dashed line, the LU torque Tlu having a magnitude obtained by multiplying the input torque Tin by a safety factor (>1) equivalent to engine running in which driving force is output only from the engine 12 is generated. Due to the response delay of the hydraulic pressure, the LU hydraulic pressure PRlu cannot follow the increase in the input torque Tin, and the LU clutch 40 is put in a slip state. A shock is generated due to the sudden engagement of the On the other hand, in the reference example shown by the solid line, in preparation for an increase in the input torque Tin due to the further accelerator pedal operation, from before the time t1b, the safety factor is larger than that of the engine running in which the driving force is output only from the engine 12. is generated by multiplying the input torque Tin by the LU torque Tlu. As a result, after time t1b, even if there is a delay in the response of the actual oil pressure, the LU torque Tlu exceeding the input torque Tin is generated (see section D). is maintained, and re-engagement of the LU clutch 40 does not occur.

As described above, according to this embodiment, when the driving force is output from the engine 12 and the electric motor MG, when the driving force is output only from the engine 12 and when the driving force is output only from the electric motor MG , the increase in the LU torque Tlu with respect to the slip amount difference ΔNs due to the feedback control in the slip control of the LU clutch 40 is reduced, so that the slip amount difference ΔNs is reduced without stopping the slip control. Even if it increases, the excess of the LU torque Tlu is suppressed. Therefore, when the vehicle travels by outputting the driving force from the engine 12 and the electric motor MG, it is possible to suppress the occurrence of a shock due to sudden engagement of the LU clutch 40 while suppressing the deterioration of the energy efficiency.

Alternatively, from another point of view, the LU clutch 40 is not brought into a released state or a state close to a released state by stopping slip control during acceleration, so the LU clutch 40 can be smoothly returned to the target slip state. , while suppressing the occurrence of a shock due to the sudden engagement of the LU clutch 40, it is possible to suppress the deterioration of the acceleration responsiveness to the accelerator operation.

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

For example, in the above embodiment, a planetary gear type automatic transmission was illustrated as the automatic transmission 24, but it is not limited to this aspect. The automatic transmission 24 may be a synchronous mesh parallel twin-shaft automatic transmission including a known DCT (Dual Clutch Transmission), a known belt-type continuously variable transmission, or the like. Also, in the above-described embodiment, the torque converter 22 is used as the hydrodynamic transmission device, but the present invention is not limited to this aspect. For example, instead of the torque converter 22, another hydrodynamic transmission such as a fluid coupling that does not amplify torque may be used as the hydrodynamic transmission. In short, the present invention can be applied to any vehicle provided with an engine and an electric motor as driving force sources and a hydrodynamic transmission device having a direct coupling clutch for transmitting the driving force from the driving force source. .

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

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

Claims (1)

It has an engine and an electric motor as driving force sources, and a direct coupling clutch that connects an input rotating member and an output rotating member, and the driving force from the driving force source is transferred from the input rotating member to the output rotating member via a fluid. A control device for a vehicle comprising a hydrodynamic transmission that transmits to
The slip of the direct coupling clutch corrects the torque capacity of the direct coupling clutch by feedback control so that the actual value of the slip amount of the direct coupling clutch, which is the rotational speed difference between the input rotating member and the output rotating member, becomes a target value. a direct coupling clutch control unit that performs control;
Hybrid control for performing 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. Department and
contains
The direct-coupling clutch control unit is configured to control when driving force is also output from the electric motor during engine running, when driving force is output only from the engine during engine running, and when motor running is performed. A control device for a vehicle, characterized in that an increase in the torque capacity of the direct coupling clutch with respect to the difference between the actual value and the target value due to the feedback control is made smaller than each other.

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