JP7708016B2 - Vehicle control device - Google Patents

Description

The present invention relates to a control device for a vehicle that has a clutch between the engine and the electric motor and the drive wheels.

There is a well-known control device for a vehicle that includes an engine, an electric motor that is connected to a power transmission path between the engine and drive wheels so that the power can be transmitted, a first clutch that is provided between the engine and the electric motor in the power transmission path, and a second clutch that is provided between the electric motor and the drive wheels in the power transmission path. For example, there is a vehicle control device described in Patent Document 1. Patent Document 1 discloses that when starting the engine, the second clutch is put into a slip state or a release state by controlling the first clutch toward an engaged state during motor driving, which uses only the electric motor as a power source when the first clutch is released and the second clutch is engaged.

Patent No. 5794377

Here, when starting the engine during motor driving, it is possible to control the second clutch to a slip state before the engine starts, for example, from the viewpoint of suppressing start-up shock and improving response. However, when the second clutch is controlled to a slip state during motor driving, if the input torque to the second clutch is low, it may become necessary to set the pack clearance of the second clutch to an unclosed state. When accelerating the vehicle from such a state, the torque capacity of the second clutch cannot be increased until the second clutch is set to a fully packed state in which the pack clearance has been closed. This may result in a deterioration in acceleration response, even though the motor driving is performed using an electric motor, which is originally more responsive than an engine.

The present invention was made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can suppress shocks when starting the engine and suppress deterioration of acceleration response when driving with an electric motor.

The gist of the first invention is that (a) a control device for a vehicle including an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be capable of transmitting power, a first clutch provided between the engine and the electric motor in the power transmission path, and a second clutch provided between the electric motor and the drive wheels in the power transmission path, (b) a switch from motor driving, in which the vehicle runs using only the electric motor as a power source when the first clutch is in a released state, to engine driving, in which the vehicle runs using at least the engine as a power source when the first clutch is in an engaged state, is performed in a state in which slip control is being performed to put the second clutch into a slip state, and (c) during the motor driving, the slip control is performed before the engine is started in association with the switch to the engine driving, and when the input torque to the second clutch during the motor driving is below the torque capacity when the second clutch is controlled to be in a packing completion state in which the pack clearance is reduced, the slip control is stopped.

According to the first invention, during motor running, slip control is performed before the engine is started, so that engine start can be started quickly and shock due to torque fluctuations accompanying engine start can be suppressed. In addition, if the input torque to the second clutch during motor running is lower than the torque capacity when controlling the second clutch to be in a packing completion state, slip control is stopped, so that even if an acceleration request is made from a state in which the input torque to the second clutch is reduced, the torque capacity of the second clutch can be easily increased. Therefore, shock at engine start can be suppressed, and deterioration of acceleration response can be suppressed during motor running by the electric motor.

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. FIG. 4 is a partial cross-sectional view showing an example of a starting clutch. FIG. 4 is a diagram showing an example of a PT characteristic of a starting clutch. FIG. 4 is a diagram showing a predetermined relationship between a WSC input torque and a WSC target differential rotation speed. 1 is a flowchart illustrating the main control operations of an electronic control device, the flowchart illustrating the control operations for suppressing shocks at the start of the engine and suppressing deterioration of acceleration response during BEV driving.

The following describes in detail an embodiment of the present invention with reference to the drawings.

Figure 1 is a diagram illustrating the general configuration of a vehicle 10 to which the present invention is applied, as well as a diagram illustrating the main parts of the control functions and control system for various controls in the vehicle 10. In Figure 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG that function as a power source. The vehicle 10 also has drive wheels 14 and a power transmission device 16 provided in the power transmission path between the engine 12 and the drive wheels 14.

The engine 12 is a known internal combustion engine. The engine torque Te of the engine 12 is controlled by an engine control device 50 provided in the vehicle 10, which is controlled by an electronic control device 90 described below.

The electric motor MG is a known rotating electric machine that functions as a motor to generate mechanical power from electric power and as a generator to generate 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 electric motor MG controls the MG torque Tm, which is the torque of the electric motor MG, by controlling the inverter 52 by an electronic control device 90 described later. For example, in the case of forward rotation, in which the rotation direction of the electric motor MG is the same as the rotation direction when the engine 12 is in operation, the MG torque Tm is a powering torque at the positive torque on the acceleration side where power is generated by the electric power from the battery 54. For example, in the case of forward rotation, the MG torque Tm is a regenerative torque at the negative torque on the deceleration side where power is generated by the power of the engine 12 or the driven force input from the drive wheel 14 side. The electric power is also the same as electric energy when there is no particular distinction. The power is also the same as driving force, torque, and force when there is no particular distinction.

The power transmission device 16 includes a case 18, which is a non-rotating member attached to the vehicle body, and includes an on-off clutch K0, a starting clutch WSC, an automatic transmission 20, a reduction gear mechanism 22, a differential gear 24 connected to the reduction gear mechanism 22, etc. The on-off clutch K0 is a first clutch provided between the engine 12 and the electric motor MG in the power transmission path between the engine 12 and the drive wheels 14. The starting clutch WSC is a second clutch provided between the electric motor MG and the drive wheels 14 in the power transmission path between the engine 12 and the drive wheels 14. The reduction gear mechanism 22 is connected to a transmission output gear 26, which is an output rotating member of the automatic transmission 20.

The power transmission device 16 also includes a pair of drive shafts 28 connected to the differential gear 24. The power transmission device 16 also includes, within the case 18, an engine connecting shaft 30 that connects the engine 12 to the on-off clutch K0, and an electric motor connecting shaft 32 that connects the on-off clutch K0 to the starting clutch WSC. The power transmission device 16 also includes, within the case 18, a mechanical oil pump 34, and a transmission member 36 that connects the electric motor connecting shaft 32 to the mechanical oil pump 34. The transmission member 36 is composed of, for example, a sprocket and a chain. The mechanical oil pump 34 is driven by the power source (engine 12, electric motor MG) to discharge hydraulic oil OIL used in the power transmission device 16.

The electric motor MG is connected to the electric motor connecting shaft 32 in the case 18 so as to be capable of transmitting power. In other words, the electric motor MG is connected to the power transmission path between the engine 12 and the drive wheels 14 so as to be capable of transmitting power.

The on-off clutch K0 is, for example, a known friction engagement device. The on-off clutch K0 has its torque capacity, K0 torque capacity Tk0, changed by the regulated K0 oil pressure PRk0 supplied from the hydraulic control circuit 56 provided in the vehicle 10, thereby switching between operating states, i.e., control states, such as an engaged state, a slip state, and a released state.

The starting clutch WSC is a wet friction engagement device, for example, composed of a multi-plate clutch pressed by an actuator. The control state of the starting clutch WSC is switched by changing the torque capacity of the starting clutch WSC, which is the WSC torque capacity Twsc, using the WSC oil pressure PRwsc, which is the adjusted oil pressure supplied from the oil pressure control circuit 56.

The input member of the starting clutch WSC is integrally connected to the motor connecting shaft 32. The output member of the starting clutch WSC is integrally connected to the transmission input shaft 38, which is the input rotating member of the automatic transmission 20.

2 is a partial cross-sectional view showing an example of a starting clutch WSC. In FIG. 2, the starting clutch WSC includes a clutch drum 100, a clutch hub 102, a separate plate 104, a friction plate 106, a piston 108, a return spring 110, a spring bearing plate 112, and a snap ring 114. The clutch drum 100 and the clutch hub 102 are provided on the same axis CS. FIG. 2 shows the radial outer periphery of the starting clutch WSC in the upper half of the axis CS. The axis CS is the axis of the electric motor connecting shaft 32, the transmission input shaft 38, etc. The clutch drum 100 is connected to, for example, the transmission input shaft 38. The clutch hub 102 is connected to, for example, the electric motor connecting shaft 32. The separate plate 104 has a plurality of substantially annular plate-shaped outer peripheries spline-fitted to the inner periphery of the cylinder portion 100a of the clutch drum 100. The friction plate 106 is interposed between a plurality of separate plates 104, and the inner peripheral edge of the plurality of approximately annular plates is spline-fitted to the outer peripheral surface of the clutch hub 102. The piston 108 is provided with a pressing portion 108a extending toward the separate plates 104 on the outer peripheral edge. The return spring 110 is interposed between the piston 108 and a spring receiving plate 112, and biases a part of the piston 108 so as to abut against the bottom plate portion 100b of the clutch drum 100. In the starting clutch WSC, an oil chamber 116 is formed between the piston 108 and the bottom plate portion 100b of the clutch drum 100. In the clutch drum 100, an oil passage 118 leading to the oil chamber 116 is formed. In the starting clutch WSC, the clutch drum 100, the piston 108, the return spring 110, the spring receiving plate 112, the oil chamber 116, and the like constitute a clutch actuator 120 as a hydraulic actuator.

In the starting clutch WSC, when the WSC oil pressure PRwsc is supplied from the hydraulic control circuit 56 to the oil chamber 116 through the oil passage 118, the WSC oil pressure PRwsc moves the piston 108 toward the separate plate 104 against the biasing force of the return spring 110, and when the pressing portion 108a of the piston 108 presses the separate plate 104 and the friction plate 106, the starting clutch WSC is switched to an engaged state. The control state of the starting clutch WSC is switched by changing the WSC torque capacity Twsc by the WSC oil pressure PRwsc.

In the starting clutch WSC, the oil chamber 116 is filled with hydraulic oil OIL, and the pressure of the piston 108 (=PRwsc x piston pressure area) counteracts the biasing force of the return spring 110 to close the clearance between the separate plate 104 and the friction plate 106, i.e., the pack clearance of the starting clutch WSC is closed, which is a so-called packing complete state. The starting clutch WSC generates a WSC torque capacity Twsc by further increasing the WSC hydraulic pressure PRwsc from the packing complete state. In other words, the packing complete state of the starting clutch WSC is a state in which the starting clutch WSC begins to have a torque capacity, i.e., a state in which the WSC torque capacity Twsc begins to be generated, by increasing the WSC hydraulic pressure PRwsc from the packing complete state. The WSC hydraulic pressure PRwsc for completing packing is the WSC hydraulic pressure PRwsc for the state in which the piston 108 reaches the stroke end and the WSC torque capacity Twsc is not being generated, that is, the pack stroke end (=PSE) pressure PRpse. In this embodiment, the WSC torque capacity Twsc when the WSC hydraulic pressure PRwsc is the PSE pressure PRpse is referred to as the PSE torque Tpse.

Figure 3 is a diagram showing an example of the PT characteristic, which is the relationship between the WSC oil pressure PRwsc and the WSC torque capacity Twsc in the starting clutch WSC. In Figure 3, when the WSC oil pressure PRwsc is equal to or higher than the PSE pressure PRpse, the WSC torque capacity Twsc is increased in proportion to the WSC oil pressure PRwsc. In addition, since the starting clutch WSC is a wet friction engagement device, in the stroke back region where the WSC oil pressure PRwsc is equal to or lower than the PSE pressure PRpse, a WSC torque capacity Twsc is generated that corresponds to the drag loss (also known as drag torque) between the separate plate 104 and the friction plate 106.

The automatic transmission 20 is a known planetary gear type automatic transmission that includes, for example, a planetary gear device and an engagement device CB. The engagement device CB includes, for example, a plurality of known friction engagement devices. The control state of each of the engagement devices CB is switched by changing the CB torque capacity Tcb, which is the torque capacity of each of the engagement devices CB, using the regulated CB hydraulic pressure PRcb supplied from the hydraulic control circuit 56.

When any of the engagement devices CB is engaged, the automatic transmission 20 is set to one of a number of gears with different gear ratios γat (=input rotational speed Ni/output rotational speed No). The input rotational speed Ni is the rotational speed of the transmission input shaft 38, and is the input rotational speed of the automatic transmission 20. The input rotational speed Ni is also the rotational speed of the output member of the starting clutch WSC. The output rotational speed No is the rotational speed of the transmission output gear 26, and is the output rotational speed of the automatic transmission 20.

The hydraulic oil OIL discharged by at least one of the mechanical oil pump 34 and the electric oil pump 58 driven by the pump motor 60 provided on the vehicle 10 is supplied to the hydraulic control circuit 56.

The vehicle 10 further includes an electronic control device 90 as a controller 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, etc., and executes various controls for the vehicle 10.

The electronic control device 90 is supplied with various signals based on the detection values of various sensors 70, 72, 74, 76, 78, 80, 82, 84, 86, etc. provided on the vehicle 10 (for example, engine speed Ne, which is the rotational speed of the engine 12; MG speed Nm, which is the rotational speed of the electric motor MG and also the rotational speed of the input side member of the starting clutch WSC; input rotational speed Ni; output rotational speed No, which corresponds to the vehicle speed V; accelerator opening θacc; throttle valve opening θth; brake-on signal Bon; battery temperature THbat; battery charge/discharge current Ibat; battery voltage Vbat; hydraulic oil temperature THoil, which is the temperature of the hydraulic oil OIL, etc.).

The electronic control device 90 outputs various command signals (e.g., engine control command signal Se, MG control command signal Sm, CB hydraulic control command signal Scb, K0 hydraulic control command signal Sk0, WSC hydraulic control command signal Swsc, electric oil pump control command signal Seop, etc.) to each of the devices 50, 52, 56, 60, etc. provided in the vehicle 10.

The electronic control device 90 is equipped with a power source control means, i.e., a power source control unit 92, and a clutch control means, i.e., a clutch control unit 94, in order to realize various controls in the vehicle 10.

The power source control unit 92 includes a function for controlling the operation of the engine 12 and a function for controlling the operation of the electric motor MG, and executes hybrid drive control using the engine 12 and the electric motor MG through these control functions.

The power source control unit 92 calculates the amount of drive required by the driver for the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to a drive demand map. The drive demand map is a relationship for calculating the drive demand that is experimentally or design-wise determined and stored in advance, i.e., is predetermined. The drive demand is, for example, the required drive torque Trdem [Nm] at the drive wheels 14. In other words, the required drive torque Trdem is the required drive power Prdem [W] at the vehicle speed V at that time. The drive demand can also be the required drive force Frdem [N] at the drive wheels 14. The power source control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the electric motor MG so as to realize the required drive power Prdem, taking into account the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 20, etc.

When the required driving power P rdem can be met only by the output of the electric motor MG, the power source control unit 92 sets the driving mode for driving the vehicle 10 to the BEV driving mode. The BEV driving mode is a motor driving mode that allows motor driving (=BEV driving) using only the electric motor MG as a power source when the disconnecting clutch K0 is in a released state. On the other hand, when the required driving power P rdem cannot be met without using at least the output of the engine 12, the power source control unit 92 sets the driving mode to the engine driving mode, i.e., the HEV driving mode. The HEV driving mode is a hybrid driving mode that allows engine driving (=HEV driving) using at least the engine 12 as a power source when the disconnecting clutch K0 is in an engaged state. On the other hand, even if the required driving power P rdem can be met only by the output of the electric motor MG, the power source control unit 92 establishes the HEV driving mode when it is necessary to charge the battery 54 or when it is necessary to warm up the engine 12, etc.

The power source control unit 92 determines whether there is an engine start request to switch the control state of the engine 12 from a stopped state to an operating state. For example, in the BEV drive mode, the power source control unit 92 determines whether there is an engine start request based on whether the required drive power P rdem has increased beyond the range that can be covered by the output of the electric motor MG alone, whether the engine 12, etc. needs to be warmed up, or whether the battery 54 needs to be charged.

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

When the power source control unit 92 determines that there is an engine start request, it controls the engine 12 and the electric motor MG to execute start control of the engine 12. For example, the power source control unit 92 outputs an MG control command signal Sm for the electric motor MG to output cranking torque Tcr in conjunction with switching of the on-off clutch K0 to the engaged state by the clutch control unit 94. In addition, the power source control unit 92 outputs an engine control command signal Se for starting fuel supply, engine ignition, etc. in conjunction with the cranking of the engine 12.

The clutch control unit 94 uses, for example, a shift map, which is a predetermined relationship, to determine whether or not the automatic transmission 20 should be shifted, and outputs a CB hydraulic control command signal Scb to switch the gear position of the automatic transmission 20 as necessary. The shift map is a predetermined relationship having a shift line for determining whether or not the automatic transmission 20 should be shifted, for example, on a two-dimensional coordinate system with the vehicle speed V and the required driving torque Trdem as variables.

Here, the power source control unit 92 executes the switch from BEV driving to HEV driving while slip control CNslp of the starting clutch WSC is being performed. Slip control CNslp is a control that puts the starting clutch WSC into a slip state. This makes it possible to suppress starting shock caused by torque fluctuations accompanying the starting control of the engine 12. The starting shock is caused, for example, by control errors in the engine torque Te when the connecting/disconnecting clutch K0 is half-engaged, during synchronization, and after synchronization.

During execution of slip control CNslp, the clutch control unit 94 controls the starting clutch WSC with a WSC torque capacity Twsc corresponding to the WSC input torque Tinw that realizes the required drive torque Trdem for the vehicle 10. In other words, during execution of slip control CNslp, the clutch control unit 94 controls the starting clutch WSC so as to obtain a WSC torque capacity Twsc equivalent to the WSC input torque Tinw that realizes the required drive torque Trdem, that is, controls the WSC hydraulic pressure PRwsc (see FIG. 3). The WSC input torque Tinw is the input torque to the starting clutch WSC. The WSC input torque Tinw that realizes the required drive torque Trdem is the torque obtained by converting the required drive torque Trdem onto the motor connecting shaft 32, taking into account losses, for example, that is, the WSC required torque.

When the starting clutch WSC is controlled so that the WSC torque capacity Twsc is equal to the WSC required torque, the power source control unit 92 performs slip control CNslp by increasing the MG power Pm, which is the output of the electric motor MG that realizes the required driving power Prdem, by a predetermined amount. The increase in the MG power Pm is consumed by putting the starting clutch WSC into a slip state, but the MG power Pm that realizes the required driving power Prdem is transmitted to the drive wheels 14.

When it is determined that there is an engine start request, it is preferable to quickly transition to HEV driving. Therefore, during BEV driving, the power source control unit 92 performs slip control CNslp before starting the engine 12 in conjunction with switching to HEV driving. In other words, during BEV driving, the power source control unit 92 performs slip control CNslp in preparation for starting the engine 12. In this embodiment, the slip control CNslp performed during BEV driving is referred to as BEV WSC slip control CNslpev.

When executing the BEV WSC slip control CNslpev, the power source control unit 92 sets, for example, a target MG rotation speed Nmtgt, which is a target value of the MG rotation speed Nm, and controls the MG power Pm by feedback control so that the MG rotation speed Nm becomes the target MG rotation speed Nmtgt. The target MG rotation speed Nmtgt is a value (= ΔNwsctgt + Ni) obtained by adding the input rotation speed Ni to the predetermined WSC target differential rotation speed ΔNwsctgt. The WSC target differential rotation speed ΔNwsctgt is a target value of the WSC differential rotation speed ΔNwsc. The WSC differential rotation speed ΔNwsc is the differential rotation speed of the starting clutch WSC, and is the slip amount, which is the rotation speed difference between the input rotation speed and the output rotation speed of the starting clutch WSC. The WSC target differential rotation speed ΔNwsctgt is the target slip amount. The input rotational speed of the starting clutch WSC is the rotational speed of the input side member of the starting clutch WSC, and is equal to the MG rotational speed Nm. The output rotational speed of the starting clutch WSC is the rotational speed of the output side member of the starting clutch WSC, and is equal to the input rotational speed Ni. In other words, the WSC differential rotational speed ΔNwsc is the rotational speed difference between the MG rotational speed Nm and the input rotational speed Ni. In this embodiment, the value obtained by subtracting the input rotational speed Ni from the MG rotational speed Nm is the WSC differential rotational speed ΔNwsc (=Nm-Ni).

In this way, the slip control CNslp is a rotational speed control CNmg that controls the MG power Pm so that the WSC differential rotational speed ΔNwsc becomes the WSC target differential rotational speed ΔNwsctgt when the starting clutch WSC is controlled with the WSC torque capacity Twsc corresponding to the WSC input torque Tinw that realizes the required drive torque Trdem.

When the WSC slip control CNslpev in the BEV mode is being executed, for example, when the WSC input torque Tinw is low, such as during creep driving, it becomes necessary to move the piston 108 toward the initial position by the biasing force of the return spring 110 in order to reduce the drag torque in the starting clutch WSC. The initial position of the piston 108 is the position of the piston 108 when the WSC oil pressure PRwsc is zero. Note that the WSC oil pressure PRwsc is not set to zero, but is applied with a predetermined pressure, and the oil passage 118 and the oil chamber 116 are filled with hydraulic oil OIL. The creep driving described above is a driving that causes the creep phenomenon in which the vehicle 10 moves slowly when, for example, the brake is released with the accelerator off.

When an acceleration request is made from a driving state in which the WSC input torque Tinw is low as described above, the starting clutch WSC cannot transmit sufficient torque until the piston 108 is moved in a direction that increases the WSC torque capacity Twsc, that is, until the starting clutch WSC is in a fully packed state. This results in wasted time while the piston 108 is moving. As a result, there is a risk that the acceleration will not be felt as good when driving in a BEV mode, even though the vehicle is driven using the electric motor MG, which is considered to have better response than the engine 12. In this way, there is a risk that a delay in acceleration response, that is, a deterioration in acceleration response, will occur when the BEV WSC slip control CNslpev is executed.

Therefore, the power source control unit 92 executes the BEV WSC slip control CNslpev (the same applies to the rotation speed control CNmg) when the WSC input torque Tinw is greater than the PSE torque Tpse, which is the WSC torque capacity Twsc when controlling the starting clutch WSC to be in the packing complete state, and does not execute the BEV WSC slip control CNslpev when the WSC input torque Tinw is smaller than the PSE torque Tpse (see FIG. 3). In other words, the power source control unit 92 stops the BEV WSC slip control CNslpev when the WSC input torque Tinw is lower than the PSE torque Tpse during BEV driving.

In addition, in order to suppress or eliminate the wasted time while the piston 108 is moving to change the starting clutch WSC from the released state to the packing completion state, it is preferable to prevent or suppress the piston 108 from moving in the direction of changing the starting clutch WSC to the released state by the biasing force of the return spring 110 from the position of the packing completion state. Therefore, the power source control unit 92 controls the starting clutch WSC by setting the PSE torque Tpse as the lower limit value of the WSC torque capacity Twsc. In other words, even if the WSC input torque Tinw falls below the PSE torque Tpse, the power source control unit 92 does not lower the command value of the WSC oil pressure PRwsc when controlling the starting clutch WSC below the PSE pressure PRpse.

During BEV driving, the starting clutch WSC is switched between an engaged state and a slip state at the boundary of the PSE torque Tpse. Therefore, there is concern about an engagement shock when the starting clutch WSC is engaged, or a release shock when the starting clutch WSC is slipped. In response to this, the WSC target differential rotation speed ΔNwsctgt in the BEV WSC slip control CNslpev is changed according to the WSC input torque Tinw. For example, the smaller the WSC input torque Tinw is, the smaller the WSC target differential rotation speed ΔNwsctgt is set. In other words, the closer the WSC input torque Tinw is to the PSE torque Tpse, the closer the WSC target differential rotation speed ΔNwsctgt is to zero.

Figure 4 is a diagram showing a predetermined relationship between the WSC input torque Tinw and the WSC target differential rotation speed ΔNwsctgt. In Figure 4, the smaller the WSC input torque Tinw, the smaller the WSC target differential rotation speed ΔNwsctgt is set. When executing the BEV-mode WSC slip control CNslpev, the power source control unit 92 calculates the WSC target differential rotation speed ΔNwsctgt by applying the WSC input torque Tinw to the relationship in Figure 4, for example, and sets the target MG rotation speed Nmtgt.

Figure 5 is a flowchart that explains the main control operations of the electronic control unit 90, which are for suppressing shocks when starting the engine 12 and suppressing deterioration of acceleration response during BEV driving, and are executed repeatedly, for example, while the BEV is driving.

In FIG. 5, each step of the flowchart corresponds to a function of the power source control unit 92. In step (hereinafter, step will be omitted) S10, it is determined whether the WSC input torque Tinw is lower than the PSE torque Tpse. If the determination in S10 is negative, it is determined in S20 whether the WSC input torque Tinw is higher than the "PSE torque Tpse + α". "α" is a hysteresis provided in the determination of whether to execute the BEV WSC slip control CNslpev, i.e., the rotation speed control CNmg. If the determination in S10 is positive, the rotation speed control CNmg is terminated in S30. If the determination in S20 is positive, the rotation speed control CNmg is activated in S40. If the determination in S20 is negative, this routine is terminated. As is clear from the flowchart in FIG. 5, the rotation speed control CNmg may be repeatedly activated and deactivated, and terminating the rotation speed control CNmg is equivalent to stopping or deactivating the rotation speed control CNmg.

As described above, according to this embodiment, the BEV WSC slip control CNslpev is performed, so that the engine 12 can be started quickly and the start shock of the engine 12 can be suppressed. In addition, if the WSC input torque Tinw is lower than the PSE torque Tpse during BEV driving, the BEV WSC slip control CNslpev is stopped, so that the WSC torque capacity Twsc is likely to be increased even if an acceleration request is made from a state in which the WSC input torque Tinw is low. Therefore, it is possible to suppress shock when starting the engine 12 and to suppress deterioration of acceleration response during BEV driving.

In addition, according to this embodiment, the BEV WSC slip control CNslpev is a rotational speed control CNmg that controls the MG power Pm so that the WSC differential rotational speed ΔNwsc becomes the WSC target differential rotational speed ΔNwsctgt, so the starting clutch WSC is appropriately set to the target slip state. In addition, it is possible to suppress unnecessary power consumption and suppress a decrease in the durability of the starting clutch WSC.

In addition, according to this embodiment, the smaller the WSC input torque Tinw is, the smaller the WSC target differential rotation speed ΔNwsctgt is set to, so that the WSC target differential rotation speed ΔNwsctgt is set to zero or a value close to zero when the BEV WSC slip control CNslpev is started or ended, thereby suppressing the release shock and engagement shock of the starting clutch WSC.

In addition, according to this embodiment, the starting clutch WSC is controlled with the PSE torque Tpse set as the lower limit of the WSC torque capacity Twsc, so that the piston 108 of the starting clutch WSC is prevented or suppressed from being moved by the return spring 110 in a direction to release the starting clutch WSC. In addition, the WSC torque capacity Twsc is quickly increased when an acceleration request is made.

The above describes in detail an embodiment of the present invention based on the drawings, but the present invention can also be applied in other aspects.

For example, in the above embodiment, the starting clutch WSC is exemplified as the second clutch provided between the electric motor MG and the drive wheels 14 in the power transmission path between the engine 12 and the drive wheels 14, but this is not limited to the embodiment. For example, instead of the starting clutch WSC, the second clutch may be an engagement device CB that can put the automatic transmission 20 in a power transmission disabled state, i.e., in a neutral state. Alternatively, if the vehicle 10 is provided with a fluid-type transmission device such as a torque converter instead of the starting clutch WSC, the second clutch may be a lock-up clutch provided in the fluid-type transmission device. Note that when the starting clutch WSC is used as the second clutch, the automatic transmission 20 does not necessarily have to be provided.

In addition, in the above-described embodiment, when the WSC input torque Tinw is lower than the PSE torque Tpse during BEV driving, if the engine 12 is started and the vehicle enters an operating state due to a request to charge the battery 54, the command value of the WSC oil pressure PRwsc may be lowered below the PSE pressure PRpse to activate the BEV WSC slip control CNslpev.

The above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

10: vehicle 12: engine 14: drive wheels 90: electronic control device (control device)
K0: Connecting/disconnecting clutch (first clutch)
MG: Electric motor WSC: Starting clutch (second clutch)

Claims (4)

A control device for a vehicle including an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be capable of transmitting power, a first clutch provided in the power transmission path between the engine and the electric motor, and a second clutch provided in the power transmission path between the electric motor and the drive wheels,
A switch from a motor running mode in which the vehicle runs using only the electric motor as a power source when the first clutch is in a released state to an engine running mode in which the vehicle runs using at least the engine as a power source when the first clutch is in an engaged state is executed in a state in which slip control is being performed to put the second clutch into a slip state,
A vehicle control device characterized in that, during the motor driving, the slip control is performed before the engine is started upon switching to the engine driving, and, when the input torque to the second clutch during the motor driving is below the torque capacity when the second clutch is controlled to bring the packing completion state in which the pack clearance is reduced, the slip control is stopped. The vehicle control device according to claim 1, characterized in that the slip control is a rotational speed control that controls the output of the electric motor so that the slip amount, which is the rotational speed difference between the input rotational speed and the output rotational speed of the second clutch, becomes a predetermined target slip amount when the second clutch is controlled with a torque capacity according to the input torque to the second clutch that realizes the required drive torque for the vehicle. The vehicle control device according to claim 2, characterized in that the smaller the input torque to the second clutch, the smaller the target slip amount is set. A vehicle control device according to any one of claims 1 to 3, characterized in that the torque capacity when the second clutch is controlled to be in the packing completion state is set as a lower limit value of the torque capacity of the second clutch to control the second clutch.