Vehicle control system

Abstract

To provide a vehicle controller capable of inhibiting impairment of acceleration responsiveness of a vehicle to acceleration operation while inhibiting a starting shock of an engine at the time of the acceleration operation from a driven state of electric motor running.SOLUTION: In a vehicle 10, if acceleration operation from a driven running state during electric motor running includes engine starting, stroke back control for moving a piston 108 of a start clutch WSC backward is prohibited. Thus, a starting shock of an engine is hard to notice during the acceleration operation, and the stroke back control for moving the piston 108 of the start clutch WSC backward prohibited on the other hand, so that the engagement of the start clutch WSC is promptly performed to improve the acceleration responsiveness of the vehicle to the acceleration operation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle control device that suppresses engine start-up shock and improves the readable responsiveness of the vehicle to an acceleration operation when accelerating from a driven traveling state during motor driving.

Background Art

[0002] A vehicle control device is known that includes an engine, an electric motor, a first clutch that disconnects and connects a power transmission path between the engine and the electric motor, and a second clutch that can mechanically connect the engine, the electric motor, and the drive wheels. When starting the engine by controlling the first clutch to engage while the second clutch is engaged and only the electric motor is used as a driving power source for traveling in a state where the first clutch is disengaged and the second clutch is engaged, the torque of the electric motor is increased and the second clutch is slip-engaged. For example, the drive device of a hybrid vehicle described in Patent Document 1 is such.

[0003] In a hybrid vehicle as described in Patent Document 1, when starting the engine by an acceleration operation with an accelerator-on operation during motor driving, while slipping the second clutch, by performing a rotational speed control for increasing the rotation of the electric motor, the drop in driving torque due to the engagement of the first clutch is compensated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when starting the above-mentioned engine, control is required to put the second clutch into a slip state in order to suppress the engine starting shock. For this reason, when the required driving torque of the vehicle is less than or equal to the back stroke end pressure torque of the second clutch, it was considered that, prior to the slip control of the second clutch, stroke back control would be performed to return the piston of the second clutch with a return spring, thereby reducing the drag torque of the second clutch to near zero, in order to smoothly initiate the slip control of the second clutch.

[0006] However, when the piston of the second clutch is moved to the release side (stroke back) by the biasing force of the return spring, there is a problem in that when accelerating by pressing the accelerator while the electric motor is running, the piston movement stroke required to increase the torque of the second clutch is large and the packing time is long, which impairs the acceleration responsiveness of the vehicle.

[0007] The present invention was made against the above circumstances, and its objective is to provide a vehicle control device that can suppress engine starting shock during acceleration operation while the vehicle is running on an electric motor, while also suppressing any impairment of the vehicle's acceleration responsiveness to acceleration operation. [Means for solving the problem]

[0008] The gist of the present invention is a vehicle control device that (a) provides an engine, an electric motor, a first clutch for disconnecting and connecting a power transmission path between the engine and the electric motor, and a second clutch capable of mechanically connecting the engine and the electric motor to the drive wheels, wherein when the engine is started by controlling the first clutch toward engagement while the vehicle is running using only the electric motor as the driving force source with the first clutch disengaged and the second clutch engaged, the torque of the electric motor is increased and the second clutch is slip-engaged; and (b) when acceleration operation during electric motor running involves starting the engine, the stroke back amount of the second clutch is greater than when the engine is not started. but small (c) The second clutch has a torque characteristic in which the transmitted torque increases gradually at a first rate of increase from zero to a predetermined backstroke end pressure when the engagement hydraulic pressure is zero, and increases linearly at a second rate of increase that is greater than the first rate of increase when the engagement hydraulic pressure exceeds the backstroke end pressure, (d) within the range of change of the transmitted torque, a stroke back region is formed below the backstroke end pressure torque corresponding to the backstroke end pressure, and (e) when the static command second clutch input torque before annealing of the command second clutch input torque calculated based on the accelerator opening is outside the stroke back region, and the dynamic command second clutch input torque after annealing of the command input torque of the second clutch is within the stroke back region, the stroke back of the second clutch is prohibited. It is about that. [Effects of the Invention]

[0009] According to the vehicle control device of the present invention, in the acceleration operation during electric motor operation, when the engine is started, the stroke back amount of the second clutch is greater than when the engine is not started. but The amount of stroke back that retracts the piston of the second clutch is reduced compared to when the engine is not starting, so that the engagement of the second clutch begins more quickly, and the acceleration response of the vehicle to acceleration operations is improved. Furthermore, within the range of change in transmitted torque, a stroke-back region is formed below the packed-stroke end pressure torque corresponding to the packed-stroke end pressure. When the static command second clutch input torque before annealing, calculated based on the accelerator opening, is outside the stroke-back region, and the dynamic command second clutch input torque after annealing, is within the stroke-back region, the stroke-back of the second clutch is prohibited. As a result, when acceleration operations involving engine starting are performed while the electric motor is running, stroke-back control is prohibited at the appropriate timing, allowing the second clutch to engage quickly, thereby improving the vehicle's acceleration responsiveness to acceleration operations. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram illustrates the schematic configuration of a vehicle to which the present invention is applied, as well as the main parts of the control functions and control systems for various control functions in the vehicle. [Figure 2] This is a cross-sectional view illustrating an example of the starting clutch configuration of the vehicle shown in Figure 1. [Figure 3] Figure 2 illustrates the characteristics between the engagement hydraulic pressure and transmitted torque of the starting clutch. [Figure 4] This is a flowchart illustrating the key aspects of the control operation of an electronic control unit. [Figure 5] This is a time chart explaining the key parts of the control operation of an electronic control unit. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Examples]

[0012] In Figure 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which function as power sources. The vehicle 10 also includes drive wheels 14 and a power transmission device 16 provided in the power transmission path between the engine 12 and the drive wheels 14.

[0013] The engine torque Te, which is the output torque of the engine 12, is controlled by the engine control device 50, which is controlled by the electronic control device 90, which will be described later.

[0014] The electric motor MG is a rotating electric machine that has the functions of both an engine and a generator, 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 output torque Tm of the electric motor MG is controlled by the inverter 52 controlled by an electronic control device 90, which will be described later. The output torque Tm is, for example, the power torque when it is a positive torque on the acceleration side and the regenerative torque when it is a negative torque on the deceleration side, in the case of forward rotation, which is the rotation direction of the engine 12.

[0015] The power transmission device 16 includes a disengagement clutch K0, a starting clutch WSC, an automatic transmission 20, a reduction gear mechanism 22, a differential gear 24, etc., within a case 18 which is a non-rotating member attached to the vehicle body. The disengagement clutch K0 is a 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 clutch provided between the engine 12 and the electric motor MG and the drive wheels 14, particularly the automatic transmission 20, in the power transmission path between the engine 12 and the drive wheels 14.

[0016] The power transmission device 16 includes a pair of drive shafts 28 connected to the differential gear 24, etc. Within the case 18, the power transmission device 16 includes an engine connecting shaft 30 that connects the engine 12 and the engagement / disengagement clutch K0, an electric motor connecting shaft 32 that connects the engagement / disengagement clutch K0 and the starting clutch WSC, etc. The power transmission device 16 also includes a mechanical oil pump 34, which is a mechanical oil pump, a transmission member 36 that connects the electric motor connecting shaft 32 and the mechanical oil pump 34, etc.

[0017] The engagement / disengagement clutch K0 is a wet or dry friction engagement device composed of, for example, a multi-plate or single-plate clutch pressed by an actuator. The engagement / disengagement clutch K0 is switched between operating states, i.e., control states, such as full engagement, slip, and disengagement, by changing the torque capacity K0 torque Tk0 of the engagement / disengagement clutch K0, which is supplied by the hydraulic pressure PRk0 of the hydraulic control circuit 56 provided in the vehicle 10.

[0018] When the engagement clutch K0 is engaged, the engine 12 and the electric motor MG are connected in a way that allows for power transmission. When the engagement clutch K0 is released, power transmission between the engine 12 and the electric motor MG is interrupted. The engagement clutch K0 functions as a first clutch that connects and disconnects the engine 12 from the electric motor MG, that is, it connects and disconnects the engine 12 from the electric motor MG.

[0019] The starting clutch WSC is controlled by the engagement hydraulic pressure Pwsc supplied from the hydraulic control circuit 56, which switches between fully engaged, slipped, and disengaged states. The starting clutch WSC suppresses shocks caused by torque fluctuations associated with starting and stopping the engine 12, and slips when the input rotational speed Ni of the automatic transmission 12 is below the rotational speed Ne of the engine 12 at low vehicle speeds. The starting clutch WSC is, for example, a wet multi-plate clutch as shown in Figure 2.

[0020] In FIG. 2, the starting clutch WSC includes a plurality of friction plates 104 and 106 overlapped with each other within a clutch drum 100, a piston 108 that presses the plurality of friction plates 104 and 106, a return spring 110 that biases the piston 108 in a direction to retreat, and an oil chamber 116 to which an engagement hydraulic pressure for advancing the piston 108 toward the plurality of friction plates 104 and 106 is supplied. And the starting clutch WSC has an engagement pressure - torque characteristic in which the transmission torque T increases as the engagement hydraulic pressure P WSC increases, in the relationship between WSC the engagement hydraulic pressure P<0000,004>and the transmission torque T WSC In the PT characteristic of this starting clutch WSC, within the transmission torque range, while the engagement hydraulic pressure P PSE increases up to the pack stroke end pressure P WSC the transmission torque T WSC increases gently at a first increase rate. When the engagement hydraulic pressure P PSE exceeds the pack stroke end pressure P PSE it increases linearly at a second increase rate greater than the first increase rate. The pack stroke end pressure P WSC corresponds to the engagement hydraulic pressure P WSC at the end of the pack packing of the piston 108. Among the change range of the transmission torque T PSE a pack stroke end pressure torque T WSC equal to or less than is formed as a stroke back region R SB .

[0021] The automatic transmission 20 is a known planetary gear type automatic transmission including, for example, one set or a plurality of sets of planetary gear devices (not shown) and an engagement device CB. The engagement device CB is represented by a plurality of clutches and brakes, and each control state such as full engagement, slip, and release can be selectively switched by changing the CB torque Tcb, which is the respective torque capacity, by the CB hydraulic pressure PRcb, which is the regulated hydraulic pressure supplied from the hydraulic control circuit 56.

[0022] The automatic transmission 20 switches gears according to the driver's accelerator operation, vehicle speed V, etc., by selectively switching the combination of operation of the engagement device CB by the electronic control device 90 described later. The input rotational speed Ni of the automatic transmission 20 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 side member of the starting clutch WSC. The AT 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.

[0023] The hydraulic oil discharged by the mechanical oil pump 34, which is connected to the motor coupling shaft 32 via the transmission member 36, and the electric oil pump 58, which is driven by the pump motor 60, is supplied to the hydraulic control circuit 56. The hydraulic control circuit 56 supplies pressure-regulated hydraulic fluids such as K0 (PRk0), WSC (PRwsc), and CB (PRcb), which are adjusted based on the hydraulic oil discharged by at least one of the mechanical oil pump 34 and the electric oil pump 58. The hydraulic oil is also used, for example, to lubricate various parts of the power transmission device 16.

[0024] Vehicle 10 is equipped with a wheel brake system 62. The wheel brake system 62 includes a brake master cylinder and a cylinder actuator (not shown) that generate brake hydraulic pressure. Each wheel of vehicle 10, including the drive wheels 14, is equipped with a wheel brake 64. The wheel brake system 62 is a brake system that applies a wheel braking torque TBw, which is the braking torque TB applied by the wheel brake 64, to the wheels according to a command from an electronic control unit 90 (described later). In the wheel brake system 62, under normal circumstances, master cylinder hydraulic pressure, which is generated from the brake master cylinder and corresponds to the brake operation amount Bra, is supplied to the wheel cylinders as brake hydraulic pressure. In the wheel brake system 62, for example, during various control operations such as ABS control, brake hydraulic pressure corresponding to the wheel braking torque TBw required for each control operation is supplied to the wheel cylinders in order to generate the wheel braking torque TBw.

[0025] Vehicle 10 is further equipped with an electronic control unit 90, which acts as a controller including a control device for vehicle 10. The electronic control unit 90 is configured to include, for example, a so-called microcomputer, and performs various controls of vehicle 10 by performing signal processing according to a pre-stored program. The electronic control unit 90 is configured to include computers for engine control, electric motor control, hydraulic control, etc., as needed.

[0026] The electronic control unit 90 receives various signals based on values ​​detected by various sensors installed in the vehicle 10 (for example, engine rotation speed sensor 70, MG rotation speed sensor 72, input rotation speed sensor 74, output rotation speed sensor 76, accelerator opening sensor 78, throttle valve opening sensor 80, brake sensor 82, battery sensor 84, oil temperature sensor 86, etc.) (for example, engine rotation speed Ne, which is the rotation speed of the engine 12; the rotation speed Nm (rpm) of the electric motor MG, which is the rotation speed of the input side member of the starting clutch WSC; input rotation speed Ni (rpm); and an automatic transmission corresponding to the vehicle speed V. The following parameters are supplied: the output rotational speed No (rpm) of the speed engine 20, the accelerator opening θacc (%) which represents the amount of accelerator operation by the driver that indicates the magnitude of the driver's acceleration operation, the throttle valve opening θth (%) which is the opening degree of the electronic throttle valve, the brake-on signal Bon which is a signal indicating that the brake pedal for activating the wheel brake 64 is being operated by the driver, the brake operation amount Bra, the battery temperature THbat, battery charge / discharge current Ibat (I), and battery voltage Vbat (V) of the battery 54, and the hydraulic oil temperature Toil (°C) which is the temperature of the hydraulic oil in the hydraulic control circuit 56.

[0027] The electronic control unit 90 outputs various command signals (for example, an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Scb for controlling the engagement device CB, a K0 hydraulic control command signal Sk0 for controlling the engagement clutch K0, a WSC hydraulic control command signal Swsc for controlling the starting clutch WSC, an electric oil pump control command signal Seop for controlling the electric oil pump 58, and a brake control command signal Sbra for controlling the wheel braking torque TBw) to each device installed in the vehicle 10 (for example, an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Scb for controlling the engagement device CB, a K0 hydraulic control command signal Sk0 for controlling the engagement clutch K0, a WSC hydraulic control command signal Swsc for controlling the starting clutch WSC, an electric oil pump control command signal Seop for controlling the electric oil pump 58, and a brake control command signal Sbra for controlling the wheel braking torque TBw).

[0028] The electronic control unit 90 is functionally equipped with a power source control means, i.e., a power source control unit 92, a clutch control means, i.e., a clutch control unit 94, and a braking control means, i.e., a braking control unit 96, in order to realize various controls in the vehicle 10.

[0029] The power source control unit 92 includes functions for controlling the operation of the engine 12 and the operation of the electric motor MG, and these control functions enable hybrid drive control of the engine 12 and the electric motor MG.

[0030] The power source control unit 92 calculates the amount of drive requested by the driver to the vehicle 10 by, for example, applying the accelerator opening θacc and the vehicle speed V to the drive request amount map. The drive request amount map is a relationship for determining the drive request amount that has been determined and stored in advance experimentally or by design. The drive request amount is, for example, the requested drive torque Trdem at the drive wheels 14. The power source control unit 92 outputs an engine control command signal Se to control the engine 12 and an MG control command signal Sm to control the electric motor MG, taking into account transmission losses, auxiliary loads, the gear ratio γat of the automatic transmission 20, etc., in order to realize the requested drive power Prdem.

[0031] The power source control unit 92 sets the vehicle 10's drive mode to an electric motor drive (BEV drive) mode, in which the vehicle runs using only the electric motor MG as a power source, if the required drive torque Trdem can be met by the output of the electric motor MG alone. On the other hand, if the required drive torque Trdem cannot be met without using at least the output of the engine 12, the power source control unit 92 sets the vehicle 10's drive mode to an engine drive mode, i.e., an HEV drive mode, in which the vehicle runs using at least the engine 12 as a power source while the engagement clutch K0 is engaged. The HEV drive mode is a hybrid drive mode that enables hybrid driving.

[0032] The power source control unit 92 determines, for example, whether or not there is an engine start request when the motor-only driving (BEV driving) is in operation, based on the fact that the requested drive torque Trdem has increased beyond the range that can be covered by the output of the electric motor MG alone.

[0033] 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 perform engine start control. For example, in conjunction with the clutch control unit 94 switching the engagement state of the disengaged clutch K0, the power source control unit 92 outputs an MG control command signal Sm for the electric motor MG to output cranking torque Tcr. Cranking torque Tcr is a predetermined torque required to increase the engine rotational speed Ne. In addition, the power source control unit 92 outputs an engine control command signal Se in conjunction with the cranking of the engine 12 to start fuel supply, engine ignition, etc.

[0034] While the vehicle 10 is in motion, the power source control unit 92 calculates a target driving force value corresponding to the required driving force of the vehicle 10, calculated based on the accelerator opening θacc and vehicle speed V from a predetermined relationship. When the vehicle is running on the electric motor, the power source control unit 92 calculates a static driving force target value PMGB corresponding to that target driving force value, and a static driving force target value P to mitigate the longitudinal G of the vehicle. MGB The target value of the dynamic driving force P after annealing. MGDThe power source control unit 92 calculates the static driving force target value P as a torque command value for controlling the output torque Tm of the electric motor MG. MGB Static command WSC input torque T converted from WSCINB And the dynamic driving force target value P MGD Dynamic command WSC input torque T converted from WSCIND The following is calculated. In electric motor operation, the motor MG outputs the dynamic command WSC input torque T. WSCIND The corresponding torque T is input to the starting clutch WSC.

[0035] The clutch control unit 94 transmits torque T to the starting clutch WSC in a manner that minimizes slippage. WSC The command value used to control this is the static driving force target value P. MGB Therefore, static command WSC input torque T WSCINB A slightly larger static WSC command torque T WSCB The dynamic command WSC input torque T is calculated and WSCIND A slightly larger dynamic WSC command torque T WSCD Calculate the dynamic WSC command torque T. WSCD As a result, static WSC command torque T WSCB This is the result of annealing. Dynamic WSC command torque T WSCD This is the command value for the transmission torque of the starting clutch WSC, and is the dynamic command WSC input torque T that controls the torque input from the electric motor MG to the starting clutch WSC. WSCIND This differs from the above.

[0036] If the power source control unit 92 determines that there is a request to start the engine while the vehicle 10 is running as a BEV, the following engine start control is performed. First, the clutch control unit 94 reduces the engagement hydraulic pressure Pwsc of the starting clutch WSC, and the transmission torque T of the starting clutch WSC is reduced. WSC However, once the output torque from the electric motor MG drops to around Tm, the dynamic WSC command torque T WSCD However, the transmission torque (engagement pressure P) of the starting clutch WSC WSC (Actual transmission torque calculated from) T WSCWhen the value obtained by adding a negative margin α exceeds the specified value, the rotational speed control of the electric motor MG by the power source control unit 92 is performed to control the slip of the starting clutch WSC. This rotational speed control is performed in a way that is not affected by the torque consumed to increase the rotational speed of the engine 12 due to the slip of the disengagement clutch K0 when the starting clutch WSC is in a slip state, by controlling the difference rotation ΔN due to the slip of the starting clutch WSC. WSC The motor MG's output is adjusted (feedback control) so that the (rpm) maintains a target rotational difference ΔNT calculated based on the input torque (output torque Tm) of the starting clutch WSC from a pre-stored relationship, and the rotational speed Nm of the motor MG is set to a higher rotational speed Nin than the input rotational speed Nin of the automatic transmission 20. In this state, when an engine start request is made, the clutch control unit 94 outputs a K0 hydraulic control command signal Sk0 to control the disengaged clutch K0 from the disengaged state toward the engaged state so that a K0 torque Tk0 is obtained to transmit the cranking torque Tcr to the engine 12. As a result, the motor MG transmits the cranking torque Tcr to the engine 12 via the disengaged clutch K0, and the engine rotational speed Ne is increased.

[0037] When an acceleration request is made during BEV driving that does not involve an engine start request, the clutch control unit 94, prior to the rotational speed control, engages the starting clutch WSC with the hydraulic pressure P WSC Lowering the throttle and returning piston 108 performs a throttle back. The throttle back is a command torque to the starting clutch WSC that is the back stroke end pressure torque T WSC This is performed prior to differential rotation control, which causes the starting clutch WSC to slip, when driving under low load conditions of 1 or less.

[0038] However, if the clutch control unit 94 receives an engine start request in response to an acceleration operation while the vehicle 10 is running as a driven BEV (electric motor), it will issue a static command WSC input torque T WSCINB The stroke back area R SB External and dynamic command WSC input torque T WSCIND This is the stroke back region R in Figure 3. SBIf it is within the area, the destination is the stroke back region R SB Since it is clear that it is outside, the stroke back described above is prohibited, and the acceleration response of the vehicle 10 is improved. Prohibition of stroke back means that the amount of stroke back is zero. The amount of stroke back is the engagement hydraulic pressure P WSC Figure 3 shows the back stroke end pressure P PSE This is the amount of retraction of the piston 108 from its packed position when it is lowered. However, the clutch control unit 94 does not prohibit the stroke back, but permits it, when it is not in the process of controlling the engine to start in response to acceleration operation during electric motor driving (BEV driving).

[0039] The braking control unit 96 sets the required braking torque TBdem based on, for example, the driver's accelerator operation (e.g., accelerator opening θacc, rate of decrease of accelerator opening θacc), vehicle speed V, gradient of the downhill road, and the driver's brake operation to activate the wheel brake 64 (e.g., brake operation amount Bra, rate of increase of brake operation amount Bra). The braking control unit 96 outputs a brake control command signal Sbra to the wheel brake device 62 to activate the wheel brake 64 so that the required wheel braking torque TBw is obtained.

[0040] Figure 4 is a flowchart illustrating the essential control functions of the clutch control unit 94 of the electronic control unit 90, specifically the control functions when engine start is determined to occur due to acceleration during BEV mode driving. In step S1 of Figure 4 (the step will be omitted hereafter), it is determined whether or not engine start control is being performed in response to an engine start request triggered by accelerator operation during electric motor driving. If the determination in S1 is denied, it means that electric motor driving is under light load with accelerator operation without engine start, so in S6, the stroke back prohibition request is turned OFF and the next control cycle begins. In the time chart of Figure 5, time t0 indicates the start of accelerator operation.

[0041] If the judgment in S1 is affirmative, then in S2, it is determined whether or not an engine start command was issued in the previous control cycle, that is, whether or not the first engine start command was issued. If the judgment in S2 is affirmative, then the engine start command has been issued for the first time, so in S3, the dynamic command WSC input command torque T WSCIND The stroke back area R SB It is determined whether or not it is inside. Figure 5 shows this state at time t1. If the determination in S3 is negative, the process is repeated, returning to the beginning of the next control cycle, and the system is put into a waiting state.

[0042] If the judgment in S3 is affirmed, in S4, the static command WSC input torque T WSCIND The stroke back area R SB It is determined whether or not it is outside. If this determination in S4 is negative, the process is repeated, returning to the beginning of the next control cycle, and the system is put into standby mode. However, if the determination in S4 is positive, the dynamic command WSC input torque T WSCIND Pack stroke end pressure torque T WSC Since the state is 1 or less, the request to prohibit stroke back is turned on in S5. This improves the acceleration responsiveness of the vehicle 10 during acceleration operations accompanied by engine start in electric motor driving mode. Figure 5 shows this state at time t3. Note that at time t2 in Figure 5, the engagement hydraulic pressure P of the starting clutch WSC is WSC The actual transmission torque T is the estimated torque calculated based on this. WSC The dynamic WSC command torque T is the value obtained by adding a margin (negative value) α to the value. WSCD The fact that it exceeded (T WSCD >T WSC -α) allows for rotational speed feedback control of the electric motor (MG).

[0043] In the above state, the decision in S2 will be rejected in the next control cycle, so in S7, the dynamic command WSC input torque T WSCD The stroke back area R SBIt is determined whether or not it is outside. If the judgment in S7 is negative, the control cycle is returned to the beginning and repeated. However, if the judgment in S7 is positive, the dynamic command WSC input torque T WSCIND The stroke back area R SB Since the state has transitioned to the outside, in S8, after the request to disable stroke back in S6 is turned OFF, the system returns to the beginning of the next control cycle.

[0044] At time t4 in Figure 5, the engine speed increase by the electric motor MG begins, and at time t5, the dynamic command WSC input torque T WSCIND Static command WSC input torque T WSCINB At time t6, the engagement of the starting clutch WSC is complete, indicating the end of engine start control. Between time t2 and t6 in Figure 5, the rotational speed Nm of the electric motor MG exceeds the input rotational speed Ni of the automatic transmission 20 due to slippage of the starting clutch WSC.

[0045] As described above, according to this embodiment, when accelerating while the vehicle 10 is running on its electric motor, if the engine is started, the stroke back of the piston 108 of the starting clutch WSC is prohibited. That is, the amount of stroke back is reduced compared to when the engine 12 is not started. As a result, the engine starting shock is less noticeable during acceleration, and the starting shock is suppressed. At the same time, because the stroke back control that moves the piston 108 of the starting clutch WSC is prohibited, the engagement of the starting clutch WSC is performed quickly, improving the acceleration responsiveness of the vehicle 10 to acceleration operations. This effect is particularly noticeable when an acceleration operation that requests engine start is performed while the vehicle is running on its electric motor in a driven state, and the vehicle is switched from a driven state to a driven state.

[0046] Furthermore, according to this embodiment, the static driving force P MGB The static WSC command torque T obtained from WSCB The stroke back area R SB External and after annealing, the dynamic command WSC input torque T WSCINDThe stroke back area R SB When this condition is met, the stroke-back control of the starting clutch WSC is prohibited. As a result, when an acceleration operation involving engine starting is performed while the electric motor is running, the stroke-back control is prohibited at the appropriate timing, allowing the starting clutch WSC to engage quickly, thereby improving the acceleration response of the vehicle 10 to the acceleration operation.

[0047] Furthermore, according to this embodiment, the dynamic command WSC input torque T after annealing is WSCIND The stroke back area R SB When disengaged from the inside, the restriction on stroke back of the starting clutch WSC is released. This release of the stroke back restriction improves the acceleration responsiveness of the vehicle 10 while it is running on electric power.

[0048] Furthermore, according to this embodiment, when an acceleration operation involving engine starting is performed while the vehicle 10 is being driven by the electric motor, the dynamic command WSC input torque T WSCIND The starting clutch WSC engages hydraulic P WSC The actual transmission torque T can be determined from this. WSC When the sum of WSCD >T WSC -α) The electric motor MG maintains the differential rotation of the starting clutch WSC through rotational speed feedback control. As a result, even if the starting clutch WSC slips, the driving force of the vehicle 10 does not become excessive, and even if the torque of the electric motor MG is consumed in increasing the rotation of the engine 12 as the engagement of the disengagement clutch K0 progresses, the torque of the electric motor MG is compensated and the rotation of the electric motor MG is maintained, thereby suppressing the starting shock when the engine starts. As a result, the shock when the engine starts while driving is suppressed.

[0049] It should be noted that the above-described embodiment is merely one example, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

[0050] For example, in the embodiment described above, the starting clutch WSC functioned as the second clutch, but any of the engagement devices CB in the automatic transmission 20 may be made to function as the second clutch. Also, if a torque converter with a lock-up clutch is used instead of the starting clutch WSC, the lock-up clutch may be made to function as the second clutch.

[0051] Furthermore, in the above-described embodiment, when acceleration operation during electric motor-driven vehicle 10 was accompanied by engine starting, stroke back of the piston 108 of the starting clutch WSC was prohibited. However, when acceleration operation during electric motor-driven vehicle 10 is accompanied by engine starting, the amount of stroke back may be smaller than when engine starting is not involved. [Explanation of Symbols]

[0052] 10: Vehicles 12: Engine 14: Drive wheels 90: Electronic control unit (control device) K0: Disconnecting clutch (first clutch) WSC: Starting Clutch (Second Clutch) MG: Electric motor T WSCB Static WSC command torque (static second clutch command torque) T WSCD Dynamic WSC command torque (dynamic second clutch command torque) T WSCINB : Static command WSC input torque (Static command 2nd clutch input torque) T WSCIND Dynamic command WSC input torque (dynamic command second clutch input torque) R SB : Stroke back area

Claims

1. A vehicle control device comprising an engine, an electric motor, a first clutch for disconnecting and connecting a power transmission path between the engine and the electric motor, and a second clutch capable of mechanically connecting the engine and the electric motor to the drive wheels, wherein when the engine is started by controlling the first clutch toward engagement while the vehicle is running using only the electric motor as the driving force source with the first clutch disengaged and the second clutch engaged, the device increases the torque of the electric motor and slip-engages the second clutch, In the acceleration operation during electric motor operation, if the engine is started, the stroke back amount of the second clutch is reduced compared to when the engine is not started. The second clutch has a torque characteristic in which the transmitted torque increases gradually at a first rate of increase from zero engagement hydraulic pressure to a predetermined backstroke end pressure, and then increases linearly at a second rate of increase that is greater than the first rate of increase when the engagement hydraulic pressure exceeds the backstroke end pressure. Within the range of change in the transmission torque, a stroke back region is formed below the back stroke end pressure torque corresponding to the back stroke end pressure. The stroke back of the second clutch is prohibited when the static command second clutch input torque, calculated based on the accelerator opening and before annealing, is outside the stroke back region, and the dynamic command second clutch input torque, after annealing, is within the stroke back region. A vehicle control device characterized by the following features.

2. When the dynamic command second clutch input torque moves out of the stroke-back region, the prohibition on the stroke-back of the second clutch is released. A vehicle control device according to feature 1.

3. When an acceleration operation involving engine starting is performed while the electric motor is running, and the dynamic command second clutch input torque exceeds the sum of the actual torque of the second clutch and a predetermined margin value, the rotational speed of the electric motor is controlled by rotational speed feedback control. A vehicle control device according to feature 1 or 2.

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