Vehicle control system

Abstract

The present invention provides a vehicle control device that can prevent or suppress the exacerbation of engine rotational decrease by an electric motor when performing regeneration control accompanied by engine rotational assistance by an electric motor. [Solution] When there is a request for filter regeneration control by cutting off fuel to the engine, the regeneration control is performed while the engine rotation is assisted by the electric motor. As a result, the engine rotation is supported by the electric motor while the filter regeneration control by cutting off fuel is being performed. In addition, the lower limit of the electric motor torque when regeneration control is performed is set to zero. As a result, when performing regeneration control with engine rotation assistance by the electric motor, the electric motor torque is not set to negative torque. Therefore, when performing regeneration control with engine rotation assistance by the electric motor, it is possible to prevent or suppress the exacerbation of the decrease in engine rotation by the electric motor.

Description

Technical Field

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[0001] The present invention relates to a control device for a vehicle equipped with a filter for collecting particulate matter contained in the exhaust gas of an engine.

Background Art

[0002] A control device for a vehicle including a power source including an engine and an electric motor, a fluid transmission device provided in a power transmission path between the power source and drive wheels, and a filter for collecting particulate matter contained in the exhaust gas of the engine is well known. For example, the hybrid vehicle described in Patent Document 1 is such a vehicle. This Patent Document 1 discloses that when there is a request for regeneration control of a filter by fuel cut to the engine, regeneration control is performed while assisting the rotation of the engine by an electric motor in a released state of a direct clutch that connects an input member and an output member of the fluid transmission device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, if the torque of the electric motor when performing regeneration control is set as negative torque, there is a risk of promoting a decrease in the rotation of the engine.

[0005] The present invention has been made against the background of the above circumstances, and an object thereof is to provide a control device for a vehicle that can prevent or suppress the promotion of a decrease in the rotation of the engine by an electric motor when performing regeneration control accompanied by rotation assistance of the engine by the electric motor.

Means for Solving the Problems

[0006] The gist of the first invention is a control device for a vehicle comprising (a) a power source including an engine and an electric motor, a fluid transmission device provided in a power transmission path between the power source and the drive wheels, and a filter for collecting particulate matter contained in the exhaust of the engine, the control device comprising (b) a regeneration control unit that performs the regeneration control while assisting the rotation of the engine with the electric motor when there is a demand for regeneration control to regenerate the filter so as to burn and remove the particulate matter collected in the filter due to a fuel cut that stops the fuel supply to the engine, and (c) the lower limit of the torque of the electric motor when performing the regeneration control is set to zero. [Effects of the Invention]

[0007] According to the first invention, when there is a demand for filter regeneration control due to fuel cut-off to the engine, the regeneration control is performed while the engine rotation is assisted by the electric motor. As a result, the engine rotation is supported by the electric motor while filter regeneration control due to fuel cut-off is being performed. In addition, the lower limit of the electric motor torque when regeneration control is performed is set to zero. As a result, when performing regeneration control accompanied by engine rotation assistance by the electric motor, the electric motor torque is not set to negative torque. Therefore, when performing regeneration control accompanied by engine rotation assistance by the electric motor, it is possible to prevent or suppress the exacerbation of the engine rotation decrease by the electric motor. [Brief explanation of the drawing]

[0008] [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 flowchart explains the key aspects of the control operation of the electronic control unit, specifically the control operation to prevent or suppress the reduction in engine speed caused by the electric motor when performing GPF auxiliary regeneration control. [Figure 3] This figure shows an example of a time chart when the control operation shown in the flowchart in Figure 2 is performed. [Modes for carrying out the invention]

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

[0010] Figure 1 is a diagram illustrating the schematic configuration of a vehicle 10 to which the present invention is applied, as well as illustrating the main parts of the control functions and control systems for various controls in the vehicle 10. In Figure 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12e and an electric motor 12m that function as a power source 12. The vehicle 10 also includes drive wheels 14 and a power transmission device 16 provided in the power transmission path between the power source 12 and the drive wheels 14.

[0011] Engine 12e is a known internal combustion engine that generates power by the combustion of fuel, for example, a gasoline engine that uses gasoline as fuel. The engine torque Te of engine 12e is controlled by an electronic control device 50, which includes an electronic throttle valve, fuel injection device, ignition device, etc., provided in the vehicle 10, and is controlled by an electronic control device 80, which will be described later.

[0012] The electric motor 12m is a rotating electric machine that has the function of an engine that generates mechanical power from electric power and a generator that generates electric power from mechanical power, and is a so-called motor generator. The electric motor 12m is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The battery 54 is an energy storage device that sends and receives power to the electric motor 12m. The MG torque Tm of the electric motor 12m is controlled by the control of the inverter 52 by an electronic control device 80, which will be described later. When the rotation direction of the electric motor 12m is forward rotation, which is the same rotation direction as when the engine 12e is operating, the MG torque Tm is the acceleration 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. Electrical power is synonymous with electrical energy unless otherwise specified. Power is synonymous with driving force, torque, and force unless otherwise specified.

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

[0014] The electric motor 12m is connected to the electric motor coupling shaft 34 within the case 18 so as to be able to transmit power. In other words, the electric motor 12m is connected so as to be able to transmit power to the power transmission path between the engine 12e and the drive wheels 14, and in particular to the power transmission path between the K0 clutch 20 and the torque converter 22. Conversely, the electric motor 12m is connected so as to be able to transmit power to the torque converter 22 and the automatic transmission 24 without going through the K0 clutch 20.

[0015] The torque converter 22 comprises a pump impeller 22p connected to the motor coupling shaft 34 and a turbine impeller 22t connected to the transmission input shaft 24i. The transmission input shaft 24i is the input rotating member of the automatic transmission 24. The pump impeller 22p is the input member of the torque converter 22, and the turbine impeller 22t is the output member of the torque converter 22. The torque converter 22 is a fluid-type transmission device installed in the power transmission path between the power source 12 and the drive wheels 14. The torque converter 22 transmits power from the power source 12 to the transmission input shaft 24i via fluid from the motor coupling shaft 34.

[0016] The torque converter 22 is equipped with an LU clutch 36 as a direct-drive clutch connecting the pump impeller 22p and the turbine impeller 22t. The LU clutch 36 is a known lock-up clutch, for example, a hydraulic friction engagement device. The control state of the LU clutch 36 is switched by changing the LU torque Tlu, which is the torque capacity of the LU clutch 36, by the LU hydraulic pressure PRlu. The LU hydraulic pressure PRlu is a regulated hydraulic pressure supplied to the LU clutch 36 from a hydraulic control circuit 38 provided in the vehicle 10.

[0017] As control states of the LU clutch 36, there are a released state (synonymous with a fully released state), a slip state in which the LU clutch 36 is engaged with slippage, and an engaged state (synonymous with a fully engaged state). When the LU clutch 36 is in the released state, the torque converter 22 is in a torque converter state where a torque amplification effect can be obtained. Also, when the LU clutch 36 is in the engaged state, the torque converter 22 is in a lock-up state (also referred to as a fully lock-up state) in which the pump impeller 22p and the turbine impeller 22t are integrally rotated.

[0018] The automatic transmission 24 is, for example, a known planetary gear type automatic transmission. The automatic transmission 24 forms a gear ratio γ (= Ni / No), that is, a gear stage, according to the driver's accelerator operation, vehicle speed V, etc. "Ni" is a signal representing the rotational speed of the transmission input shaft 24i, and represents the transmission input rotational speed, which is the input rotational speed of the automatic transmission 24. "No" is a signal representing the rotational speed of the transmission output shaft 24o, and represents the transmission output rotational speed, which is the output rotational speed of the automatic transmission 24.

[0019] The K0 clutch 20 is a hydraulic friction engagement device constituted by, for example, a multi-plate or single-plate clutch. The control states such as the engaged state, slip state, and released state of the K0 clutch 20 are switched by changing the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, by the K0 hydraulic pressure PRk0. The K0 hydraulic pressure PRk0 is a regulated hydraulic pressure supplied from the hydraulic control circuit 38 to the K0 clutch 20.

[0020] When the K0 clutch 20 is in the engaged state, the power of the engine 12e is transmitted to the drive wheels 14 sequentially through the K0 clutch 20, torque converter 22, automatic transmission 24, propeller shaft 26, differential gear 28, drive shaft 30, etc. The power of the electric motor 12m is transmitted to the drive wheels 14 sequentially through the torque converter 22, automatic transmission 24, propeller shaft 26, differential gear 28, drive shaft 30, etc., regardless of the control state of the K0 clutch 20.

[0021] Vehicle 10 includes a mechanical oil pump 40. The oil pump 40 is connected to the pump impeller 22p and is rotationally driven by the power source 12 to discharge the hydraulic fluid FLD used in the power transmission device 16. The hydraulic fluid FLD discharged by the oil pump 40 is supplied to the hydraulic control circuit 38. The hydraulic control circuit 38 supplies the regulated LU hydraulic pressure PRlu, K0 hydraulic pressure PRk0, etc., based on the hydraulic fluid FLD discharged by the oil pump 40. The hydraulic fluid FLD functions as the hydraulic fluid supplied to the LU clutch 36, the hydraulic fluid supplied to the K0 clutch 20, etc.

[0022] Vehicle 10 includes a catalyst 56 and a GPF (Gasoline Particulate Filter) 58. The catalyst 56 and the GPF 58 are provided in the exhaust pipe 12ex of the engine 12e. The catalyst 56 is a known three-way catalyst that purifies, for example, hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), etc. contained in the exhaust of the engine 12e. The GPF 58 is provided on the downstream side of the catalyst 56. The GPF 58 is a filter that collects particulate matter (PM, also synonymous) contained in the exhaust of the engine 12e. By providing the GPF 58 in addition to the catalyst 56, the exhaust can be further purified.

[0023] Vehicle 10 further includes an electronic control unit 80 as a controller that includes a control device for the vehicle 10 related to the control of the engine 12e, the LU clutch 36, etc. The electronic control unit 80 is configured to include a so-called microcomputer including, for example, a CPU, a RAM, a ROM, an input / output interface, etc. The CPU executes various controls of the vehicle 10 by performing signal processing according to a program stored in the ROM in advance while using the temporary storage function of the RAM, for example.

[0024] The electronic control unit 80 receives various signals based on detection signals from various sensors installed in the vehicle 10. Examples of these sensors include the engine rotation speed sensor 60, the MG rotation speed sensor 62, the input rotation speed sensor 64, the output rotation speed sensor 66, the accelerator pedal position sensor 68, the throttle valve position sensor 70, and the brake sensor 72. Other examples of these sensors include the battery sensor 74 and the hydraulic oil temperature sensor 76. Examples of these signals include the engine rotation speed Ne, the MG rotation speed Nm, the transmission input rotation speed Ni, the transmission output rotation speed No, the accelerator pedal position θacc, the throttle valve position θth, and the brake operation amount Bra. Other examples of these signals include the battery temperature THbat, the battery charge / discharge current Ibat, the battery voltage Vbat, and the hydraulic oil temperature THfld.

[0025] Engine rotational speed Ne is a signal representing the rotational speed of engine 12e. MG rotational speed Nm is a signal representing the rotational speed of electric motor 12m. Transmission input rotational speed Ni is the same value as turbine rotational speed Nt, which is the output rotational speed of torque converter 22. Transmission output rotational speed No is the rotational speed corresponding to vehicle speed V. Accelerator opening θacc is a signal representing the amount of accelerator operation by the driver, which represents the magnitude of the driver's acceleration operation. Throttle valve opening θth is a signal representing the opening of the electronic throttle valve. Brake operation amount Bra is a signal representing the magnitude of the driver's brake pedal depression operation, i.e., the magnitude of the brake operation. Battery temperature THbat is a signal representing the temperature of battery 54. Battery charge / discharge current Ibat is a signal representing the current charged to battery 54 and the current discharged from battery 54. Battery voltage Vbat is a signal representing the voltage of battery 54. Hydraulic oil temperature THfld is a signal representing the temperature of hydraulic oil FLD.

[0026] The electronic control unit 80 calculates the remaining charge state (SOC) [%] based on, for example, the battery charge / discharge current Ibat and the battery voltage Vbat. The remaining charge state (SOC) is the remaining charge of the battery 54 and is a value that indicates the charge state of the battery 54. The electronic control unit 80 calculates the chargeable power Win [W] and dischargeable power Wout [W] of the battery 54 based on, for example, the battery temperature THbat and the remaining charge state (SOC).

[0027] The electronic control unit 80 outputs various command signals to each device installed in the vehicle 10. These devices include, for example, the hydraulic control circuit 38, the engine control unit 50, and the inverter 52. The various command signals include, for example, the LU hydraulic control command signal Slu, the engine control command signal Se, and the MG control command signal Sm. The LU hydraulic control command signal Slu is a command signal for controlling the LU clutch 36 and is the instruction hydraulic pressure for the LU hydraulic pressure PRlu. The engine control command signal Se is a command signal for controlling the engine 12e. The MG control command signal Sm is a command signal for controlling the electric motor 12m.

[0028] The electronic control unit 80 includes a power source control unit 82 and a clutch control unit 84 in order to implement various controls in the vehicle 10.

[0029] The power source control unit 82 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 predetermined relationship for determining the amount of drive requested, which is, for example, determined and stored experimentally or by design in advance. The amount of drive requested is, for example, the required drive torque Trdem and the required drive force Frdem at the drive wheels 14.

[0030] The power source control unit 82 calculates a target system shaft torque Tsystgt to achieve the required drive torque Trdem, taking into consideration transmission losses, auxiliary loads, gear ratio γ, etc. The target system shaft torque Tsystgt is the target value of the system shaft torque Tsys and corresponds to the power source torque Tsp required for the vehicle 10. The power source torque Tsp is the torque of the power source 12 and is the sum of the engine torque Te and the MG torque Tm. The system shaft torque Tsys is, for example, the torque on the transmission input shaft 24i or the motor coupling shaft 34. The power source control unit 82 outputs control command signals (Se, Sm) to control the power source 12 so that the power source torque Tsp is obtained to achieve the target system shaft torque Tsystgt.

[0031] The clutch control unit 84 determines the control region using, for example, a predetermined lock-up region diagram, and outputs an LU hydraulic control command signal Slu to the hydraulic control circuit 38 to control the LU clutch 36 so that the control state corresponding to the determined control region is realized. The control region includes a lock-up region corresponding to the engaged state, a release region corresponding to the released state, and a slip region corresponding to the slip state.

[0032] Here, if a large amount of PM accumulates in the GPF58, its performance may be reduced due to clogging, or exhaust emissions may be obstructed. Therefore, the power source control unit 82 is functionally equipped with a regeneration control unit 86 that performs GPF regeneration control CNgpf in order to avoid or suppress functional impairment of the engine 12e due to excessive PM accumulation in the GPF58. Functional impairment of the engine 12e due to excessive PM accumulation includes, for example, a decrease in engine output due to increased exhaust pressure loss and worsening fuel efficiency. GPF regeneration control CNgpf is a regeneration control that regenerates the GPF58 so that the PM collected in the GPF58 is burned and removed. In other words, GPF regeneration control CNgpf is a regeneration control that regenerates the GPF58 by controlling the engine 12e so that the PM collected in the GPF58 is more easily burned.

[0033] The regeneration control unit 86 determines whether or not a predetermined amount Qpmf or more of PM has accumulated in the GPF 58. The regeneration control unit 86 estimates the amount of PM accumulated in the GPF 58 Qpm based on vehicle conditions such as the mileage traveled by the vehicle 10, the operating time of the engine 12e, and the load on the engine 12e, for example, after the execution of the previous GPF regeneration control CNgpf. The regeneration control unit 86 determines whether or not a predetermined amount Qpmf or more of PM has accumulated in the GPF 58 based on whether or not the accumulated amount Qpm is equal to or greater than a predetermined amount Qpmf. The predetermined amount Qpmf is, for example, a predetermined threshold for determining whether or not a process to regenerate the GPF 58 is necessary. Alternatively, the regeneration control unit 86 may determine whether or not a predetermined amount Qpmf or more of PM has accumulated in the GPF 58 based on whether or not the pressure difference between the upstream pressure and the downstream pressure of the GPF 58 is equal to or greater than a predetermined pressure difference. The predetermined pressure difference is, for example, a predetermined threshold for determining whether or not the pressure difference is such that exhaust flow is obstructed and engine performance is impaired.

[0034] If the regeneration control unit 86 determines that a predetermined amount of PM (Qpmf or more) has accumulated in the GPF 58, it turns on the GPF regeneration control CNgpf request flag and performs GPF regeneration control CNgpf. If the regeneration control unit 86 determines that a predetermined amount of PM (Qpmf or more) has not accumulated in the GPF 58, it prohibits the request for GPF regeneration control CNgpf and does not perform GPF regeneration control CNgpf. In addition, the regeneration control unit 86 may also turn on the GPF regeneration control CNgpf request flag if, for example, the driver requests that the GPF 58 be regenerated.

[0035] If the regeneration control unit 86 turns on the GPF regeneration control CNgpf request flag, for example, when the accelerator is off, it performs GPF regeneration control CNgpf by fuel cut, which stops the fuel supply to the engine 12e. The regeneration control unit 86 determines whether there is a request for GPF regeneration control CNgpf by fuel cut by determining whether or not a predetermined amount Qpmf or more of PM has accumulated in the GPF 58.

[0036] In the fuel-cut-induced GPF regeneration control CNgpf, it is desirable to rotate the engine 12e while the fuel is cut off to introduce air into the GPF 58 and promote PM combustion. Even in the fuel-cut state, if the LU clutch 36 is engaged, it is possible to introduce air into the GPF 58 by rotating the engine 12e from the drive wheel 14 side. Alternatively, even when the LU clutch 36 is disengaged and the fuel is cut off, it is possible to introduce air into the GPF 58 by rotating the engine 12e with the electric motor 12m. This increases the opportunities for GPF regeneration control CNgpf.

[0037] When the regeneration control unit 86 receives a request for GPF regeneration control CNgpf due to fuel cut, it performs GPF regeneration control CNgpf due to fuel cut with the LU clutch 36 engaged. Alternatively, when the regeneration control unit 86 receives a request for GPF regeneration control CNgpf due to fuel cut, it performs GPF regeneration control CNgpf due to fuel cut with the LU clutch 36 disengaged, while assisting the rotation of the engine 12e with the electric motor 12m. Assisting the rotation of the engine 12e with the electric motor 12m means that the electric motor 12m rotates the engine 12e in the fuel cut state, supporting it so that the engine rotation speed Ne does not decrease. In other words, assisting the rotation of the engine 12e with the electric motor 12m means that the electric motor 12m assists the rotation of the engine 12e, and provides support for the rotation of the engine 12e. In this embodiment, the GPF regeneration control CNgpf, which involves fuel cut accompanied by rotational assistance of the engine 12e by the electric motor 12m, is referred to as the auxiliary regeneration control of the GPF 58, or GPF auxiliary regeneration control CNgpfa.

[0038] The clutch control unit 84 determines whether it is impossible to engage the LU clutch 36 when there is a request for GPF regeneration control CNgpf due to fuel cut. The clutch control unit 84 determines whether it is impossible to engage the LU clutch 36 based, for example, on whether the hydraulic oil temperature THfld is below a predetermined low oil temperature THfldlow. Therefore, when the hydraulic oil temperature THfld is below the predetermined low oil temperature THfldlow, it is impossible to engage the LU clutch 36. The predetermined low oil temperature THfldlow is, for example, a predetermined lower limit value that ensures controllability of the engagement state of the LU clutch 36. If the clutch control unit 84 determines that it is not impossible to engage the LU clutch 36, that is, if it determines that it is possible to engage the LU clutch 36, it controls the LU clutch 36 to be engaged. If the clutch control unit 84 determines that it is impossible to engage the LU clutch 36, it controls the LU clutch 36 to be released.

[0039] When a request for GPF regeneration control CNgpf by fuel cut is made, the regeneration control unit 86 will engage the LU clutch 36 if possible, and will perform GPF regeneration control CNgpf by fuel cut with the LU clutch 36 engaged. When a request for GPF regeneration control CNgpf by fuel cut is made, the regeneration control unit 86 will not engage the LU clutch 36 if possible, and will perform GPF regeneration control CNgpf by fuel cut with the LU clutch 36 disengaged, while assisting the rotation of the engine 12e with the electric motor 12m.

[0040] If the regeneration control unit 86 is unable to engage the LU clutch 36, it determines, for example, whether it is possible to assist the rotation of the engine 12e with the electric motor 12m, based on the state of the battery 54. The state of the battery 54 is represented by at least one of the following: battery temperature THbat, battery charge / discharge current Ibat, battery voltage Vbat, remaining charge SOC, chargeable power Win, and dischargeable power Wout. For example, if the dischargeable power Wout is less than a predetermined power, the regeneration control unit 86 determines that it is not possible to assist the rotation of the engine 12e with the electric motor 12m. If the regeneration control unit 86 determines that it is not possible to assist the rotation of the engine 12e with the electric motor 12m, it does not perform GPF regeneration control CNgpf, or GPF assist regeneration control CNgpfa, by cutting off fuel while the LU clutch 36 is disengaged.

[0041] The regeneration control unit 86 calculates the MG torque Tm when performing GPF-assisted regeneration control CNgpfa while assisting the rotation of the engine 12e with the electric motor 12m. During deceleration, the regeneration control unit 86 uses the value obtained by subtracting the torque of the engine 12e in the fuel-cut state from, for example, the target system shaft torque Tsystgt as the MG torque Tm when performing GPF-assisted regeneration control CNgpfa. The torque of the engine 12e in the fuel-cut state is the estimated engine torque Tee at the time of fuel cut, i.e., the estimated engine torque (F / C) Teefc. The estimated engine torque Tee is an estimated value of the engine torque Te, and is calculated based on, for example, the engine rotational speed Ne, the throttle valve opening θth, etc. The estimated engine torque (F / C) Teefc includes the F / C torque and the transient estimated engine torque Tee from the estimated engine torque Tee in the combustion state of the engine 12e until it decreases to the F / C torque after fuel cut. The F / C torque is the converged estimated engine torque Tee after fuel cut. The estimated engine torque Tee of engine 12e in its combustion state is, in particular, the minimum torque that engine 12e can achieve in its combustion state, i.e., the minimum engine torque Temin. The minimum engine torque Temin is the minimum value of engine torque Te within the range where misfires do not occur.

[0042] When the vehicle deceleration requirement is weak during deceleration driving, the power source control unit 82 sets the target system shaft torque Tsystgt to a value corresponding to the minimum engine torque Temin, which is greater than the estimated engine torque (F / C) Teefc. Therefore, during the execution of the GPF auxiliary regeneration control CNgpfa when the vehicle deceleration requirement is weak, the electric motor 12m simulates a state in which the engine 12e is operating at minimum torque with the LU clutch 36 disengaged. A weak vehicle deceleration requirement is assumed to occur, for example, when the vehicle is coasting with the accelerator and brakes off.

[0043] The power source control unit 82 sets the target system shaft torque Tsystgt to a value smaller than the minimum engine torque Temin when there is a strong demand for vehicle deceleration during deceleration driving, with the demand for vehicle deceleration decreasing as the demand for vehicle deceleration increases. A strong demand for vehicle deceleration is assumed to occur, for example, when decelerating with the accelerator off and the brake on. For example, the larger the brake operation amount Bra, the stronger the demand for vehicle deceleration. The faster the accelerator pedal is released from the accelerator-on state to the accelerator-off state, the stronger the demand for vehicle deceleration may be.

[0044] Incidentally, when there is a strong demand for vehicle deceleration, the target system shaft torque Tsystgt may be set lower than the estimated engine torque (F / C) Teefc. In this case, the MG torque Tm (=Tsystgt-Teefc) when GPF-assisted regeneration control CNgpfa is performed is set to a negative torque. When the MG torque Tm is set to a negative torque when GPF-assisted regeneration control CNgpfa is performed, it may exacerbate the decrease in engine speed 12e.

[0045] Therefore, the regeneration control unit 86 does not set the MG torque Tm to a negative torque when performing GPF-assisted regeneration control CNgpfa. In other words, the regeneration control unit 86 sets the lower limit of the MG torque Tm to zero when performing GPF-assisted regeneration control CNgpfa. For example, if the target system shaft torque Tsystgt is less than or equal to the estimated engine torque (F / C) Teefc, the regeneration control unit 86 sets the MG torque Tm to zero when performing GPF-assisted regeneration control CNgpfa. In other words, when calculating the MG torque Tm when performing GPF-assisted regeneration control CNgpfa, the regeneration control unit 86 does not calculate the MG torque Tm if the target system shaft torque Tsystgt is not considered to be greater than the estimated engine torque (F / C) Teefc. Not calculating the MG torque Tm is equivalent to guarding the MG torque Tm at zero [Nm].

[0046] Figure 2 is a flowchart illustrating the main part of the control operation of the electronic control unit 80, and is a flowchart illustrating the control operation to prevent or suppress the acceleration of the rotational speed of the engine 12e by the electric motor 12m when performing GPF auxiliary regeneration control CNgpfa, and is, for example, executed repeatedly.

[0047] In Figure 2, first, in step S10, which corresponds to the function of the regeneration control unit 86 (the step will be omitted hereafter), it is determined whether or not there is a request for GPF regeneration control CNgpf by fuel cut. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, in S20, which corresponds to the function of the clutch control unit 84, it is determined whether or not it is impossible to engage the LU clutch 36. In other words, it is determined whether or not the LU clutch 36 is unable to engage. If the determination in S20 is negative, in S30, which corresponds to the functions of the clutch control unit 84 and the regeneration control unit 86, GPF regeneration control CNgpf by fuel cut is performed with the LU clutch 36 engaged. If the determination in S20 is positive, in S40, which corresponds to the function of the regeneration control unit 86, it is determined whether or not it is possible to assist the rotation of the engine 12e with the electric motor 12m. If the determination in S40 is negative, this routine is terminated. If the judgment in S40 is affirmed, then in S50, which corresponds to the functions of the clutch control unit 84 and the regeneration control unit 86, GPF auxiliary regeneration control CNgpfa is performed with the LU clutch 36 in the disengaged state. In this case, if the target system shaft torque Tsystgt is less than or equal to the estimated engine torque (F / C) Teefc, the MG torque Tm is set to zero [Nm] and guard is applied.

[0048] Figure 3 shows an example of a time chart when the control operation shown in the flowchart of Figure 2 is performed. In Figure 3, time t1 indicates the moment when the accelerator is released. With the accelerator released, the fuel supply to the engine 12e is stopped, and the estimated engine torque Tee is reduced toward the F / C torque. Time t2 indicates the moment when the electric motor 12m begins to provide support when the GPF auxiliary regeneration control CNgpfa is performed with the LU clutch 36 disengaged, because the estimated engine torque Tee has become smaller than the minimum engine torque Temin. In this embodiment, shown by the solid line, the vehicle deceleration requirement is weak under normal conditions, and the target system shaft torque Tsystgt is set to a value equivalent to the minimum engine torque Temin. In this case, the MG torque Tm when performing the GPF auxiliary regeneration control CNgpfa is the value obtained by subtracting the estimated engine torque (during F / C) Teefc from the target system shaft torque Tsystgt. The comparative example shown by the dashed line represents a case where a high degree of vehicle deceleration is required, and the target system shaft torque Tsystgt is set to a value smaller than the minimum engine torque Temin. In this case, if the target system shaft torque Tsystgt is smaller than the estimated engine torque (F / C) Teefc (see section A of the dashed line), the MG torque Tm when GPF auxiliary regeneration control CNgpfa is performed will be a negative torque (see from time t3 onwards). In contrast, in this embodiment shown by the double-dash line, if the target system shaft torque Tsystgt is less than or equal to the estimated engine torque (F / C) Teefc, the MG torque Tm is guarded at zero [Nm] (see from time t3 onwards).

[0049] As described above, according to this embodiment, when there is a request for GPF regeneration control CNgpf due to fuel cut, GPF auxiliary regeneration control CNgpfa is performed. As a result, while GPF regeneration control CNgpf due to fuel cut is being performed, the rotation of the engine 12e is supported by the electric motor 12m. In addition, the lower limit of the MG torque Tm is set to zero when GPF auxiliary regeneration control CNgpfa is performed. As a result, when GPF auxiliary regeneration control CNgpfa is performed, the MG torque Tm is not made into a negative torque. Therefore, when GPF auxiliary regeneration control CNgpfa is performed, it is possible to prevent or suppress the exacerbation of the reduction in engine 12e rotation by the electric motor 12m.

[0050] Furthermore, according to this embodiment, during deceleration, the value obtained by subtracting the estimated engine torque (F / C) Teefc from the target system shaft torque Tsystgt is used as the MG torque Tm when performing GPF-assisted regeneration control CNgpfa. This allows GPF-assisted regeneration control CNgpfa to be executed appropriately.

[0051] Furthermore, according to this embodiment, when the vehicle deceleration requirement is weak, the target system shaft torque Tsystgt is set to a value corresponding to the minimum engine torque Temin, which is greater than the estimated engine torque (F / C) Teefc. As a result, when the GPF auxiliary regeneration control CNgpfa is executed when the vehicle deceleration requirement is weak, the electric motor 12m simulates a state in which the engine 12e is operating at minimum torque with the LU clutch 36 disengaged.

[0052] Furthermore, according to this embodiment, when the vehicle deceleration requirement is high, the target system shaft torque Tsystgt is set to a value smaller than the minimum engine torque Temin as the vehicle deceleration requirement increases. In addition, when the target system shaft torque Tsystgt is less than or equal to the estimated engine torque (F / C) Teefc, the MG torque Tm is set to zero when performing GPF auxiliary regeneration control CNgpfa. As a result, when performing GPF auxiliary regeneration control CNgpfa, the MG torque Tm is not set to a negative torque.

[0053] Furthermore, according to this embodiment, if it is possible to engage the LU clutch 36 when there is a request for GPF regeneration control CNgpf by fuel cut, the GPF regeneration control CNgpf by fuel cut is performed with the LU clutch 36 engaged. If it is not possible to engage the LU clutch 36 when there is a request for GPF regeneration control CNgpf by fuel cut, the GPF auxiliary regeneration control CNgpfa is performed with the LU clutch 36 disengaged. This ensures that there is an appropriate opportunity for the regeneration of the GPF 58.

[0054] Furthermore, according to this embodiment, when the hydraulic oil temperature THfld is below a predetermined low oil temperature THfldlow, it is not possible to engage the LU clutch 36. As a result, during GPF regeneration control CNgpf, the controllable control state of the LU clutch 36 is appropriately determined, and the GPF 58 is appropriately regenerated according to the determined control state of the LU clutch 36.

[0055] Although embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other embodiments.

[0056] For example, in the above-described embodiment, the present invention can be applied to a vehicle equipped with an engine 12e, an electric motor 12m, a torque converter 22, and a GPF 58. Furthermore, as a fluid-type transmission device, other fluid-type transmission devices such as a fluid coupling may be used instead of the torque converter 22. Also, the torque converter 22 does not necessarily need to be equipped with an LU clutch 36. Even in this configuration, when there is a demand for GPF regeneration control CNgpf due to fuel cut, GPF auxiliary regeneration control CNgpfa is performed, and the lower limit of the MG torque Tm when GPF auxiliary regeneration control CNgpfa is performed is set to zero. Therefore, a certain effect can be obtained in which the electric motor 12m can prevent or suppress the acceleration of the engine 12e's rotational speed reduction when GPF auxiliary regeneration control CNgpfa is performed.

[0057] Furthermore, in the above-described embodiment, the automatic transmission 24 may be replaced with, for example, a known belt-type continuously variable transmission.

[0058] Furthermore, in the above-described embodiment, the engine 12e may be replaced with, for example, a diesel engine. If the engine 12e is a diesel engine, a DPF (Diesel Particulate Filter) is used as the filter for collecting PM.

[0059] 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. [Explanation of Symbols]

[0060] 10: Vehicle 12: Power source 12e: Engine 12m: Electric motor 14: Drive wheels 22: Torque converter (fluid transmission device) 22p: Pump impeller (input component) 22t: Turbine impeller (output component) 36: LU clutch (direct drive clutch) 58: GPF (filter) 80: Electronic control unit (control unit) 82: Power source control unit 86: Regeneration control unit FLD: Hydraulic oil

Claims

1. A control device for a vehicle comprising a power source including an engine and an electric motor, a fluid-type transmission device provided in a power transmission path between the power source and the drive wheels, and a filter for collecting particulate matter contained in the exhaust gas of the engine, In the event of a request for regeneration control to regenerate the filter so as to burn and remove the particulate matter collected in the filter by a fuel cut-off that stops the fuel supply to the engine, the system includes a regeneration control unit that performs the regeneration control while assisting the rotation of the engine with the electric motor. The regeneration control unit is characterized in that it sets the lower limit of the torque of the electric motor to zero when performing the regeneration control.

2. The vehicle control device according to claim 1, characterized in that the regeneration control unit, during deceleration driving, uses a value obtained by subtracting the torque of the engine in the fuel cut state from the torque of the power source required for the vehicle as the torque of the electric motor when performing the regeneration control.

3. The system further includes a power source control unit that, when the vehicle deceleration requirement is weak, sets the torque of the power source required for the vehicle to a value greater than the engine torque in the fuel cut-off state, and corresponding to the minimum torque achievable by the engine in a combustion state, while when the vehicle deceleration requirement is strong, sets the torque of the power source required for the vehicle to a value smaller than the minimum torque as the vehicle deceleration requirement increases. The vehicle control device according to claim 2, characterized in that the regeneration control unit sets the torque of the electric motor to zero when performing the regeneration control if the torque of the power source required for the vehicle is less than or equal to the torque of the engine in the fuel cut state.

4. The vehicle further comprises a direct-drive clutch that connects the input member and output member of the fluid-type transmission device. The vehicle control device according to any one of claims 1 to 3, characterized in that, when it is possible to engage the direct drive clutch when a request for regeneration control is made, the regeneration control is performed with the direct drive clutch engaged, while when it is not possible to engage the direct drive clutch when a request for regeneration control is made, the regeneration control is performed with the direct drive clutch disengaged while the motor assists the rotation of the engine.

5. The vehicle control device according to claim 4, characterized in that the direct-drive clutch cannot be put into the engaged state when the temperature of the hydraulic fluid supplied to the direct-drive clutch is below a predetermined low oil temperature which is the lower limit value for which controllability of the engaged state can be ensured.

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