Vehicle control devices

Abstract

The present invention provides a vehicle control device, the vehicle comprising a driving force source including an electric motor, a stepped transmission including a plurality of engagement devices, a mechanical hydraulic pump driven by the electric motor, and an electric hydraulic pump, the vehicle control device being capable of reducing shock generated during slow-run interruption recovery control. When recovering from slow-run interruption control to slow-run control, the electric hydraulic pump (60) is driven before the MG rotational speed Nm of the electric motor MG increases immediately after the start of recovery to slow-run control, thereby ensuring hydraulic pressure. Thereafter, the mechanical hydraulic pump (58) is driven along with the increase in the MG rotational speed Nm of the electric motor MG, thereby ensuring hydraulic pressure. As a result, the CB hydraulic pressure PRcb of the speed-changing engagement device CB can be made to follow the indicated pressure, thereby suppressing shock generated by a sudden increase in the CB hydraulic pressure PRcb of the speed-changing engagement device CB.

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle including at least an electric motor as a driving force source and capable of executing creep cut control for stopping the rotation of the electric motor under predetermined conditions. Background Art

[0002] Patent Document 1 describes the following: In a vehicle capable of traveling by a traction motor capable of driving the rear wheels, when the vehicle is to be driven by the traction motor, an electric hydraulic pump is driven to supply a preparatory pressure for compensating for the lost travel to a clutch (engaging device) for a shifting gear of an automatic transmission, thereby quickly outputting the driving force requested by the driver when transitioning from motor travel to engine travel.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-233272 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Furthermore, in a vehicle equipped with at least an electric motor as a driving force source, a stepped transmission comprising multiple engagement devices, and a mechanical hydraulic pump and an electric hydraulic pump driven by the power output from the electric motor, a vehicle is considered that, when predetermined conditions are met, executes a slow-down control that places the automatic transmission in neutral and stops the rotation of the electric motor. During the slow-down control, the mechanical hydraulic pump is not driven as the rotation of the electric motor stops, and thus the hydraulic pressure of the working fluid supplied to the engaged engagement device during the slow-down control gradually decreases. Furthermore, if predetermined recovery conditions are met during the slow-down control, a slow-down recovery control is executed that returns the engagement device whose hydraulic pressure was reduced during the slow-down control to the engaged state and increases the rotational speed of the electric motor. If the output shaft of the stepped transmission is rotating when this slow-down recovery control is executed, the shock transmitted to the drive wheels when the engagement device is returned to the engaged state may be increased.

[0008] The present invention is made against the background of the above situation, and its purpose is to provide a control device for a vehicle, wherein the vehicle has a driving force source including at least an electric motor, a stepped transmission including a plurality of engagement devices, a mechanical hydraulic pump driven by an electric motor, and an electric hydraulic pump, wherein the control device of the vehicle can reduce the impact generated when the slow-moving interruption recovery control is performed.

[0009] Solutions to Problems

[0010] The gist of the first scheme is that (a) a vehicle control device is applicable to a vehicle comprising: a driving force source including at least an electric motor; a stepped transmission having a plurality of engagement devices and capable of forming a plurality of gears according to a combination of the engagement devices to be engaged; a mechanical hydraulic pump driven by power output from the electric motor; and an electric hydraulic pump, the vehicle control device being capable of executing slow-run control and slow-run interrupt control, in which the specified engagement device is engaged within a range in which the power transmission of the stepped transmission is cut off and a slow-run torque is output from the electric motor to the stepped transmission, and in which the slow-run control is terminated and the electric motor is stopped from rotating, and the vehicle control device is characterized in that (b) when the recovery conditions for returning from the slow-run interrupt control to the slow-run control are met, the rotation speed of the electric motor is increased after the electric hydraulic pump is driven.

[0011] The main purpose of the second scheme is that, based on the first scheme, the control device of the vehicle is characterized in that when the recovery condition is met and the prescribed conditions that are likely to cause impact during the recovery transition period to the slow-moving control are met, the engagement pressure of the engagement device is controlled so as to gradually increase.

[0012] The main purpose of the third scheme is that, based on the second scheme, the specified conditions are that all of the following situations are met: the rotation speed of the output shaft of the stepped transmission is greater than zero; the state in which the motor stops rotating has lasted for more than a predetermined time; and the shift position of the stepped transmission is a power transmission cut-off position.

[0013] A fourth aspect is based on any one of the first to third aspects, wherein the vehicle control device is characterized in that the return condition includes a vehicle speed being greater than zero during the creep interruption control.

[0014] Effects of the Invention

[0015] According to the first embodiment, when resuming from slow-run interruption control to slow-run control, hydraulic pressure is ensured by driving the electric hydraulic pump immediately after the resumption of slow-run control, prior to the increase in the motor's rotational speed. Furthermore, hydraulic pressure is then ensured by driving the mechanical hydraulic pump as the motor's rotational speed increases. This allows the engagement pressure of the coupling device to track the indicated pressure, suppressing the shock caused by a sudden increase in the engagement pressure of the coupling device.

[0016] According to the second embodiment, when resuming from slow-climbing control, if a predetermined condition that easily causes a shock during the transition period of resuming control is met, the engagement pressure of the engagement device is controlled to gradually increase, thereby reducing the shock caused by the increase in the engagement pressure of the engagement device. As a result, the shock caused during the transition period of resuming from slow-climbing control can be suppressed.

[0017] According to the third scheme, by determining whether the rotation speed of the output shaft of the stepped transmission is greater than zero, whether the state of the motor stopping rotation has lasted for more than a predetermined specified time, and whether the shift position of the stepped transmission is a power transmission cut-off position, it is possible to easily determine whether an impact is likely to occur during the recovery transition period to the slow-moving control.

[0018] According to the fourth aspect, whether or not to resume the slow-moving control can be easily determined based on whether or not the vehicle speed is greater than zero during the slow-moving interruption control. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and is a functional block diagram showing a main portion of a control function for performing various controls in the vehicle.

[0020] Figure 2 It is briefly shown Figure 1 A diagram showing the main points of the structure of an automatic transmission.

[0021] Figure 3 It means to use Figure 2 An engagement operation table showing combinations of engagement devices for each speed change to establish a shift stage of an automatic transmission.

[0022] Figure 4 This is a flowchart for explaining the main part of the control operation of the electronic control device.

[0023] Figure 5 This is a timing chart for explaining the control state of the electronic control device.

[0024] [Description of Reference Numerals]

[0025] 10: Vehicles

[0026] 24: Automatic transmission (stepped transmission)

[0027] 36: Transmission output shaft (output shaft)

[0028] 58: Mechanical hydraulic pump

[0029] 60: Electric hydraulic pump

[0030] 100: Electronic control unit (control device)

[0031] MG: Electric motor (driving force source)

[0032] CB: Coupling device for speed change (coupling device) DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following embodiments, the drawings are appropriately simplified or deformed, and may not accurately depict the size ratios and shapes of various parts.

[0034] [Example]

[0035] Figure 1 1 is a schematic configuration diagram of a vehicle 10 including an electronic control device 100 according to an embodiment of the present invention, and is a functional block diagram showing a main portion of a control function for performing various controls in the vehicle 10 .

[0036] The vehicle 10 includes an engine 12 and a motor MG as driving force sources for traveling, a power transmission device 16 provided on a power transmission path between the engine 12 and a pair of drive wheels 14, and an electronic control unit 100. The vehicle 10 is a hybrid vehicle.

[0037] The engine 12 is a well-known internal combustion engine. The engine 12 controls the engine torque Te [Nm] as the output torque of the engine 12 by controlling a throttle actuator, a fuel injection device, an ignition device, etc. provided in the engine 12 by an electronic control unit 100 described later.

[0038] The power transmission device 16 is provided within a case 18, a non-rotating member mounted on the vehicle body, and includes, in order from the engine 12 side, an engine connecting shaft 30, a K0 clutch 20, a motor connecting shaft 32, a torque converter 22, and an automatic transmission 24. Furthermore, the power transmission device 16 includes, for example, a differential gear 26 connected to a transmission output shaft 36, which serves as an output rotating member of the automatic transmission 24, and a pair of axles 38 connected to the differential gear 26.

[0039] The engine connecting shaft 30 connects the engine 12 and the K0 clutch 20. The K0 clutch 20 is located between the engine 12 and the electric motor MG in the power transmission path between the engine 12 and the pair of drive wheels 14. The motor connecting shaft 32 connects the K0 clutch 20 to the torque converter 22. The K0 clutch 20 is a hydraulic friction engagement device composed of, for example, a multi-plate or single-plate clutch. The K0 clutch 20 switches its operating state by varying the K0 torque Tk0 [Nm], which represents the transfer torque capacity (engaging force of the K0 clutch 20), of the K0 clutch 20 using the regulated hydraulic pressure, or K0 hydraulic pressure PRk0 [Pa], supplied from the hydraulic control circuit 56. This changes the K0 torque Tk0 [Nm], which represents the K0 clutch 20's engagement force, thereby switching the operating state. In the vehicle 10, when the K0 clutch 20 is engaged, the engine 12 and the torque converter 22 are connected via the K0 clutch 20, enabling power transmission. On the other hand, when the K0 clutch 20 is disengaged, power transmission between the engine 12 and the torque converter 22 is disconnected. The K0 clutch 20 functions as a clutch for connecting or disconnecting the engine 12 and the electric motor MG. When the K0 clutch 20 is in an engaged state, one end of the motor coupling shaft 32 is connected to the engine 12 via the K0 clutch 20 .

[0040] The torque converter 22 is a well-known fluid power transmission device. It includes a pump impeller 22a connected to the motor connecting shaft 32, a turbine impeller 22b connected to the transmission input shaft 34, which serves as the input rotating member of the automatic transmission 24, and a lockup clutch 22c that directly connects the pump impeller 22a and the turbine impeller 22b. A mechanical hydraulic pump 58 is connected to the pump impeller 22a. The mechanical hydraulic pump 58 is driven by power output from at least one of the engine 12 and the electric motor MG, thereby discharging hydraulic fluid into the hydraulic control circuit 56. The hydraulic fluid discharged from the mechanical hydraulic pump 58 is used as the initial pressure for the various hydraulic pressures (such as K0 hydraulic pressure and PRk0 hydraulic pressure) to be regulated by the hydraulic control circuit 56.

[0041] The torque converter 22 is connected to the engine 12 via the K0 clutch 20. An automatic transmission 24 is connected to the torque converter 22 in a power-transmittable manner, and is provided in a power transmission path between the torque converter 22 and the pair of drive wheels 14. The torque converter 22 and the automatic transmission 24 each constitute a portion of the power transmission path between the driving force source for travel (the engine 12 and the electric motor MG) and the pair of drive wheels 14.

[0042] The electric motor MG is a rotating electrical machine having both the function of a motor that generates mechanical power from electricity and the function of a generator that generates electricity from mechanical power, and is a so-called electric generator. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52. The battery 54 is a storage device that transfers electricity to and from the electric motor MG. The electric motor MG controls the inverter 52 by using the electronic control unit 100 described later, thereby controlling the MG torque Tm [Nm], which is the output torque of the electric motor MG. For example, when the rotation direction of the electric motor MG is the same as when the engine 12 is running, that is, forward rotation, the MG torque Tm is a power running torque if it is a positive torque on the acceleration side, and a regenerative torque if it is a negative torque on the deceleration side. The above-mentioned electric power is synonymous with electric energy unless otherwise specified. The above-mentioned power is synonymous with torque and force unless otherwise specified.

[0043] The electric motor MG is connected to the motor connecting shaft 32 within the case 18 in a power-transmittable manner. Specifically, the electric motor MG is connected to the power transmission path between the K0 clutch 20 and the torque converter 22 in a power-transmittable manner. To put it another way, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 in a power-transmittable manner without passing through the K0 clutch 20.

[0044] The automatic transmission 24 is provided between the driving force source for travel (the engine 12 and the electric motor MG) and the pair of drive wheels 14. It is a well-known planetary gear type automatic transmission having, for example, one or more planetary gear sets and a plurality of speed-changing coupling devices CB. The plurality of speed-changing coupling devices CB selectively engage the rotating elements or the rotating elements and non-rotating elements that constitute the one or more planetary gear sets. The speed-changing coupling devices CB are, for example, wet multi-plate hydraulic friction coupling devices such as clutches and brakes. The speed-changing coupling devices CB each utilize the regulated hydraulic pressure supplied from the hydraulic control circuit 56, i.e., the CB hydraulic pressure PRcb [Pa], to change the respective CB torques Tcb [Nm], which serve as the transfer torque capacity, thereby switching between operating states such as the engaged state and the disengaged state. It should be noted that the automatic transmission 24 corresponds to the stepped transmission of the present invention.

[0045] Figure 2This is a diagram schematically illustrating the structure of the automatic transmission 24. The automatic transmission 24 includes a first planetary gear set 42, a second planetary gear set 44, a third planetary gear set 46, and a fourth planetary gear set 48. The first planetary gear set 42 is a single-pinion planetary gear set consisting of a sun gear S1, pinion gears P1, carrier CA1, and ring gear R1. The second planetary gear set 44 is a double-pinion planetary gear set consisting of a sun gear S2, multiple pairs of meshing pinion gears P1 and P2, carrier CA2, and ring gear R2. The third planetary gear set 46 is a single-pinion planetary gear set consisting of a sun gear S3, pinion gears P3, carrier CA3, and ring gear R3. The fourth planetary gear set 48 is a single-pinion planetary gear set consisting of a sun gear S4, pinion gears P4, carrier CA4, and ring gear R4. The automatic transmission 24 changes the speed of the rotation of the transmission input shaft 34 and outputs it through the transmission output shaft 36. The first planetary gear set 42 and the second planetary gear set 44 are so-called Ravinar type planetary gear sets in which the planetary gear carrier CA1 and the planetary gear carrier CA2 are integrally formed and the ring gear R1 and the ring gear R2 are integrally formed. Figure 2 As shown, the plurality of shift engagement devices CB are composed of six hydraulic friction engagement devices, namely, a clutch C1 , a clutch C2 , a clutch C3 , a clutch C4 , a brake B1 , and a brake B2 .

[0046] The sun gear S1 of the first planetary gear set 42 is connectable to the case 18 via a brake B1. The planetary carrier CA1 of the first planetary gear set 42 and the planetary carrier CA2 of the second planetary gear set 44 are connected to the transmission input shaft 34. The ring gear R1 of the first planetary gear set 42 and the ring gear R2 of the second planetary gear set 44 are connectable to the sun gear S3 of the third planetary gear set 46 and the sun gear S4 of the fourth planetary gear set via a clutch C1, and are also connectable to the ring gear R3 of the third planetary gear set 46 via a clutch C3. The sun gear S2 of the second planetary gear set 44 is connectable to the sun gear S3 of the third planetary gear set 46 and the sun gear S4 of the fourth planetary gear set 48 via a clutch C2.

[0047] The sun gear S3 of the third planetary gear set 46 and the sun gear S4 of the fourth planetary gear set 48 are connected to each other. Furthermore, the sun gears S3 and S4 are connectable to the ring gear R1 of the first planetary gear set 42 and the ring gear R2 of the second planetary gear set 44 via clutch C1, and are also connectable to the sun gear S2 of the second planetary gear set 44 via clutch C2. The planetary carrier CA3 of the third planetary gear set 46 is connected to the transmission output shaft 36. The ring gear R3 of the third planetary gear set 46 is connectable to the ring gear R1 of the first planetary gear set 42 and the ring gear R2 of the second planetary gear set 44 via clutch C3, and is also connectable to the case 18 via brake B2. The planetary carrier CA4 of the fourth planetary gear set 48 is connected to the transmission input shaft 34. The ring gear R4 of the fourth planetary gear set 48 is connectable to the planetary carrier CA3 of the third planetary gear set 46 and the transmission output shaft 36 via clutch C4.

[0048] The automatic transmission 24 is a stepped automatic transmission that establishes one of multiple speed stages (also called gears) with different speed ratios (also called gear ratios) γat (=AT input shaft rotational speed Ni / AT output shaft rotational speed No) by engaging any of the speed-changing coupling devices CB. The AT input shaft rotational speed Ni is the rotational speed of the transmission input shaft 34, representing the input rotational speed of the automatic transmission 24. The AT input shaft rotational speed Ni is the same as the turbine rotational speed Nt (rpm), the output rotational speed of the torque converter 22. Therefore, the AT input shaft rotational speed Ni can be represented by the turbine rotational speed Nt. The AT output shaft rotational speed No is the rotational speed of the transmission output shaft 36, representing the output rotational speed of the automatic transmission 24. The transmission output shaft 36 corresponds to the output shaft of the present invention.

[0049] The automatic transmission 24 can form a plurality of speed stages by combining the engagement and release of a plurality of speed-changing engagement devices CB (clutches C1 to C4 and brakes B1 and B2). Figure 3 The automatic transmission 24 is shifted by using the engagement operation table showing the combinations of the various shift engagement devices CB for establishing the shift speed of the automatic transmission 24. Figure 3 In FIG. 1 , “○” indicates engagement of the speed-changing engagement device CB, and “×” indicates disengagement of the speed-changing engagement device CB. Figure 3 As shown, the automatic transmission 24 is configured to be switchable to ten forward speeds and reverse speeds Rev from 1st to 10th by changing the combination of engagement and release of each speed-changing engagement device CB of the automatic transmission 24 .

[0050] Return to Figure 1The differential gear 26 is a well-known differential gear device that transmits driving force while appropriately applying a rotational difference to a pair of axles 38 respectively connected to the pair of drive wheels 14 .

[0051] The electric hydraulic pump 60 (EOP) is driven by a pump motor 62 dedicated to the electric hydraulic pump 60, discharging hydraulic fluid into the hydraulic control circuit 56. The hydraulic fluid discharged into the hydraulic control circuit 56 is used as the initial pressure for each hydraulic pressure to be regulated by the hydraulic control circuit 56. The pump motor 62 is a dedicated motor for driving the electric hydraulic pump 60. The driving state of the pump motor 62 is controlled by the electronic control unit 100, which will be described later.

[0052] The shift operation position POSsh of the shift lever 68 is, for example, each operation position such as "P operation position", "R operation position", "N operation position", and "D operation position". The P operation position is a parking operation position in which the automatic transmission 24 is set to the P gear (= a gear position in which the transmission output shaft 36 is mechanically fixed so as not to rotate). The R operation position is a reverse travel operation position in which the automatic transmission 24 is set to the R gear (= a gear position in which the vehicle 10 can travel in reverse). The N operation position is a neutral operation position in which the automatic transmission 24 is set to the N gear (= a gear position in which the vehicle 10 can travel in reverse). The D operation position is a forward travel operation position in which the automatic transmission 24 is set to the D gear (= a gear position in which all the gear positions of the automatic transmission 24 are used to perform automatic shift control and forward travel is possible). By selecting the "P operating position," "R operating position," "N operating position," and "D operating position," the shift range of the automatic transmission 24 is switched to "P" (P range), "R" (R range), "N" (N range), and "D" (D range), respectively. Of the shift ranges of the automatic transmission 24, "P" and "N" are non-driving ranges, while "R" and "D" are driving ranges.

[0053] Here, when the shift operation position POSsh is switched to the "P operation position" or the "N operation position", as shown in FIG. Figure 3 As shown, clutch C2 and brake B2 are engaged. Both clutch C2 and brake B2 are speed-changing engagement devices CB that are engaged when establishing first gear (1st) and reverse gear (Rev). By engaging clutch C2 and brake B2 with the shift operating position POSsh switched to the "N operating position" or "P operating position," only one speed-changing engagement device CB (clutch C1 or clutch C3) needs to be engaged when the shift operating position POSsh is switched to the "D operating position" or "R operating position," enabling quick vehicle start-up.

[0054] The hydraulic control circuit 56 uses the hydraulic pressure of the hydraulic fluid discharged from at least one of the mechanical hydraulic pump 58 and the electric hydraulic pump 60 as the initial pressure to supply the required hydraulic fluid to various components within the case 18. For example, based on the CB hydraulic pressure control signal Scb input from the electronic control unit 100, the hydraulic control circuit 56 generates a control hydraulic pressure for engaging or disengaging the speed-changing engagement device CB provided in the automatic transmission 24 and outputs it to the actuators of the respective speed-changing engagement devices CB. Based on the LU hydraulic pressure control signal Slu input from the electronic control unit 100, the hydraulic control circuit 56 generates a clutch hydraulic pressure Plu [Pa] for engaging or disengaging the lockup clutch 22c of the torque converter 22 and outputs it to the actuator of the lockup clutch 22c. Based on the K0 hydraulic pressure control signal Sk0 input from the electronic control unit 100, the hydraulic control circuit 56 generates a control hydraulic pressure PRk0 for engaging or disengaging the K0 clutch 20 and outputs it to the actuator of the K0 clutch 20. The hydraulic fluid discharged from at least one of the mechanical hydraulic pump 58 and the electric hydraulic pump 60 is used to control the operating states of the K0 clutch 20 and the shift engagement device CB.

[0055] In the power transmission device 16, when the K0 clutch 20 is engaged, the power output from the engine 12 is transmitted from the engine connecting shaft 30 to the pair of drive wheels 14 in this order, via the K0 clutch 20, the motor connecting shaft 32, the torque converter 22, the automatic transmission 24, the differential gear 26, and the pair of axles 38. Regardless of the operating state of the K0 clutch 20, the power output from the electric motor MG is transmitted from the motor connecting shaft 32 to the pair of drive wheels 14 in this order, via the torque converter 22, the automatic transmission 24, the differential gear 26, and the pair of axles 38.

[0056] The electronic control device 100 is comprised of a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, and input / output interfaces. The CPU processes signals according to programs pre-stored in the ROM while utilizing the RAM's temporary storage function, thereby executing various controls for the vehicle 10. The electronic control device 100 may also include various computers for engine control, motor control, hydraulic control, and the like, as needed. It should be noted that the electronic control device 100 corresponds to the control device of the present invention.

[0057] Various signals based on detection values ​​of various sensors (e.g., engine rotation speed sensor 70, turbine rotation speed sensor 72, output shaft rotation speed sensor 74, motor rotation speed sensor 76, accelerator opening sensor 78, throttle opening sensor 80, battery sensor 82, fluid temperature sensor 84, gear position sensor 86, etc.) provided in the vehicle 10 are input to the electronic control unit 100 (e.g., engine rotation speed Ne [rpm], turbine rotation speed Nt which is the same as AT input shaft rotation speed Ni, vehicle speed V [rpm], etc.). km / h] corresponding to the AT output shaft rotation speed No, the rotation speed of the electric motor MG, namely the MG rotation speed Nm [rpm], the driver's accelerator operation amount indicating the magnitude of the driver's acceleration operation, namely the accelerator opening θacc [%], the opening of the electronic throttle, namely the throttle opening θth [%], the battery temperature THbat [°C] of the battery 54, the battery charge and discharge current Ibat [A], the battery voltage Vbat [V], the liquid temperature THoil [°C] of the working fluid, the shift operation position POSsh indicating the operation position of the shift lever 68 operated by the driver, etc.).

[0058] Various command signals (such as an engine control signal Se for controlling the engine 12, a motor control signal Sm for controlling the electric motor MG, a CB hydraulic control signal Scb for controlling the transmission engagement device CB, a K0 hydraulic control signal Sk0 for controlling the K0 clutch 20, a LU hydraulic control signal Slu for controlling the lockup clutch 22c, an EOP control signal Seop for controlling the electric hydraulic pump 60, etc.) are output from the electronic control unit 100 to each device of the vehicle 10 (such as the engine 12, the inverter 52, the hydraulic control circuit 56, the pump motor 62, etc.).

[0059] The electronic control device 100 functionally includes a hybrid control unit 102 , a clutch control unit 104 , a speed change control unit 106 , a slow-moving control unit 108 , a slow-moving interruption control unit 110 , and a slow-moving interruption recovery control unit 112 .

[0060] The hybrid control unit 102 functionally includes an engine control unit 102a for controlling the operation of the engine 12 and a motor control unit 102b for controlling the operation of the motor MG via the inverter 52. These control functions are used to perform hybrid drive control of the engine 12 and the motor MG.

[0061] The hybrid control unit 102 calculates the driver's drive requirement for the vehicle 10 by, for example, applying the accelerator opening θacc and the vehicle speed V to a drive requirement map. The drive requirement map is a map that stores the relationship between the accelerator opening θacc and the vehicle speed V and the drive requirement in advance through experiments or design. The drive requirement is, for example, the required drive torque Trdem [Nm] for the pair of drive wheels 14. The required drive torque Trdem is the driving torque for traveling that the driver expects. To put it another way, the required drive torque Trdem is the required drive power Prdem [W] at the current vehicle speed V. As the drive requirement, the required drive force Frdem [N] for the pair of drive wheels 14, the required AT output shaft torque for the transmission output shaft 36, etc. may also be used. In the calculation of the drive requirement, the AT output shaft rotation speed No, etc. may also be used instead of the vehicle speed V.

[0062] The hybrid control unit 102 outputs an engine control signal Se for controlling the engine 12 and a motor control signal Sm for controlling the electric motor MG, taking into account factors such as transmission loss, auxiliary load, the gear ratio γat of the automatic transmission 24, the power input Win [W] and the power output Wout [W] of the battery 54, to achieve the required drive power Prdem. The engine control signal Se is, for example, a command value for the power of the engine 12, i.e., the engine power Pe [W], for outputting the engine torque Te at the current engine rotational speed Ne. The motor control signal Sm is, for example, a command value for the power consumption Wm [W] of the electric motor MG, for outputting the MG torque Tm at the current MG rotational speed Nm.

[0063] The inputtable power Win of the battery 54 is the maximum power that can be input, which limits the input power of the battery 54 and indicates the input limit of the battery 54. The dischargeable power Wout of the battery 54 is the maximum power that can be output, which limits the output power of the battery 54 and indicates the output limit of the battery 54. The inputtable power Win and the dischargeable power Wout of the battery 54 are calculated by the electronic control unit 100 based on, for example, the battery temperature THbat and the state of charge (SOC) [%] of the battery 54 (the ratio of the actual stored charge to the predetermined full charge capacity).

[0064] When the required drive torque Trdem is provided solely by the output of the electric motor MG, the hybrid control unit 102 sets the driving mode to the motor driving (BEV driving) mode. In the BEV driving mode, the hybrid control unit 102 performs BEV driving, in which the driving force is output only from the electric motor MG, one of the driving force sources (engine 12 and electric motor MG), with the K0 clutch 20 disengaged. On the other hand, when the required drive torque Trdem is not provided without at least the output of the engine 12, the hybrid control unit 102 sets the driving mode to the engine driving mode, i.e., the hybrid driving (HEV driving) mode. In the HEV driving mode, the hybrid control unit 102 performs HEV driving, in which the driving force is output from at least the engine 12, one of the driving force sources (engine 12 and electric motor MG), with the K0 clutch 20 engaged. On the other hand, even when the required drive torque Trdem is provided solely by the output of the electric motor MG, the hybrid control unit 102 establishes the HEV driving mode if the state of charge (SOC) of the battery 54 is less than a predetermined engine start threshold or if the engine 12 or the like needs to be warmed up. The engine start threshold is a predetermined SOC threshold used to determine whether the engine 12 must be forcibly started and the battery 54 must be charged. In this way, the hybrid control unit 102 appropriately switches between the BEV driving mode and the HEV driving mode based on the required drive torque Trdem and other factors.

[0065] The engine control unit 102a controls the engine torque Te to achieve the required drive torque for the vehicle 10. The motor control unit 102b controls the MG torque Tm to achieve the required drive torque for the vehicle 10. Specifically, in the BEV driving mode, the motor control unit 102b controls the MG torque Tm to achieve the required drive torque Trdem. In the HEV driving mode, the engine control unit 102a controls the engine torque Te to achieve all or part of the required drive torque Trdem, and the motor control unit 102b controls the MG torque Tm to make up for the torque shortfall of the engine torque Te relative to the required drive torque Trdem.

[0066] When the shift operating position POSsh is switched to the "N operating position" or "P operating position" while the vehicle 10 is stopped, for example, due to a driver's braking operation (e.g., depression of a brake pedal for activating wheel brakes (not shown), the retarding control unit 108 performs retarding control to control the automatic transmission 24 to a neutral state and output a retarding torque Tcrp from the electric motor MG to the automatic transmission 24. The retarding torque Tcrp is set to a torque sufficient to cause the vehicle to travel slowly when the automatic transmission 24 is shifted to the D range or the R range, for example.

[0067] As described above, during the slow-moving control, the automatic transmission 24 is controlled to be in the neutral state. Figure 3 As shown in the engagement operation table, the clutch C2 and the brake B2 are engaged. Even if the clutch C2 and the brake B2 are engaged, the neutral state in which the power transmission is cut off is maintained in the automatic transmission 24. In addition, the clutch C2 and the brake B2 are the speed-changing engagement device CB formed in the 1st gear and the reverse gear Rev. By engaging the clutch C2 and the brake B2 during the slow-running control, the speed-changing engagement device CB engaged when the vehicle starts becomes one (clutch C1 or clutch C3), thereby enabling a quick vehicle start. It should be noted that the clutch C2 and the brake B2 correspond to the prescribed engagement devices that are engaged within the range in which the power transmission of the stepped transmission is cut off of the present invention.

[0068] When a predetermined slow-moving stop condition is satisfied during slow-moving control, such as when the vehicle 10 has been stopped for a predetermined time or longer, or when the slow-moving control has been in effect for a predetermined time or longer, the slow-moving stop control unit 110 terminates slow-moving control and stops the electric motor MG. Stopping the electric motor MG reduces power consumption in the electric motor MG.

[0069] Furthermore, during the slow-run interruption control, the rotation of the electric motor MG is stopped, and therefore the mechanical hydraulic pump 58 is also stopped. Furthermore, in the vehicle 10 of this embodiment, the electric hydraulic pump 60 is stopped when the shift position of the automatic transmission 24 is in the N or P range to eliminate the driving sound generated by the electric hydraulic pump 60. Therefore, during the slow-run interruption control, the hydraulic fluid discharged from the mechanical hydraulic pump 58 and the electric hydraulic pump 60 is not supplied to the hydraulic control circuit 56. As a result, the hydraulic pressure of the hydraulic fluid supplied to the clutch C2 and the brake B2 gradually decreases over time.

[0070] When a predefined slow-motion interruption recovery condition is met during slow-motion interruption control, the slow-motion interruption recovery control unit 112 returns from slow-motion interruption control to slow-motion control. Specifically, when the slow-motion interruption recovery condition is met, the slow-motion interruption recovery control unit 112 increases the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2, which were hydraulically reduced during slow-motion interruption control, thereby increasing the MG rotational speed Nm of the electric motor MG. It should be noted that the slow-motion interruption recovery condition corresponds to the return condition from slow-motion interruption control to slow-motion control according to the present invention.

[0071] The slow-run interruption recovery condition is that the automatic transmission 24 is in the N or P gear and either of the following conditions (a) and (b) are met. Condition (a) is that the vehicle speed V is greater than zero, i.e., the AT output shaft rotational speed No is greater than zero (0 rpm). Furthermore, condition (b) is that a request to start the engine 12 is issued.

[0072] If the vehicle speed V, as condition (a), is greater than zero, that is, if the AT output shaft rotational speed No is greater than zero, the vehicle 10 is in a state of coasting. Therefore, in order to quickly output the retarding torque Tcrp to prevent coasting, the vehicle speed V being greater than zero is defined as the retarding interruption recovery condition. Condition (a) is determined, for example, based on whether the AT output shaft rotational speed No is greater than a threshold that indicates that the vehicle 10 is moving.

[0073] When a request to start the engine 12 is issued as condition (b), the K0 clutch 20 is engaged as a start control for the engine 12, and the MG torque Tm of the electric motor MG is transmitted to the engine 12 as the starting torque Tcrk of the engine 12. At this time, since the electric motor MG is driven, the issuance of the request to start the engine 12 is defined as a slow-running interruption recovery condition.

[0074] The slow-running interruption recovery control unit 112 determines that the slow-running interruption recovery condition has been satisfied when the automatic transmission 24 is in the N or P gear and the vehicle speed V is greater than zero. Alternatively, the slow-running interruption recovery control unit 112 determines that the slow-running interruption recovery condition has been satisfied when the automatic transmission 24 is in the N or P gear and a request to start the engine 12 has been issued. Upon determining that the slow-running interruption recovery condition has been satisfied, the slow-running interruption recovery control unit 112 executes slow-running interruption recovery control to increase the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 to engage the clutch C2 and the brake B2, and to increase the MG rotational speed Nm of the electric motor MG.

[0075] Here, immediately after resuming from the slow-motion interruption control, since the mechanical hydraulic pump 58 and the electric hydraulic pump 60 are not driven, the slow-motion interruption recovery control unit 112 drives the electric hydraulic pump 60 simultaneously with the establishment of the slow-motion interruption recovery condition. Next, the slow-motion interruption recovery control unit 112 increases the MG rotational speed Nm of the electric motor MG after a predetermined time tx has elapsed from the slow-motion interruption control recovery determination time point. As described above, when the slow-motion interruption recovery condition is established, the MG rotational speed Nm of the electric motor MG is increased after the electric hydraulic pump 60 is driven. Specifically, by driving the electric hydraulic pump 60 prior to the increase in the MG rotational speed Nm of the electric motor MG, the hydraulic fluid discharged from the electric hydraulic pump 60 can be used to increase the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 from the start of the slow-motion interruption recovery control.

[0076] Furthermore, after the predetermined time tx has elapsed, the MG rotational speed Nm of the electric motor MG increases, thereby driving the mechanical hydraulic pump 58. The hydraulic fluid discharged from the mechanical hydraulic pump 58 can increase the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2. Therefore, the crawling interruption recovery control unit 112 uses the hydraulic pressure of the hydraulic fluid discharged from the mechanical hydraulic pump 58 after the MG rotational speed Nm increases as the initial pressure to increase the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2. It should be noted that the predetermined time tx is determined in advance through experimentation or design and is set, for example, to the time during which the hydraulic fluid discharged from the electric hydraulic pump 60 can control the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2.

[0077] Here, when executing the slow-running interruption recovery control, if the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 are suddenly increased when the AT output shaft rotation speed No is greater than zero, the impact generated at this time may be transmitted to the transmission output shaft 36 and cause discomfort to the driver.

[0078] In the automatic transmission 24, the planetary carrier CA3 of the third planetary gear set 46 is directly connected to the transmission output shaft 36. Furthermore, the brake B2 is an engagement device connecting the ring gear R3 of the third planetary gear set 46 and the case 18. Therefore, when the brake B2 hydraulic pressure PRb2 increases rapidly, the shock generated by the sudden increase in the B2 hydraulic pressure PRb2 is easily transmitted to the transmission output shaft 36 via the third planetary gear set 46. Furthermore, the clutch C2 is an engagement device connecting the sun gear S3 of the third planetary gear set 46 and the sun gear S2 of the second planetary gear set 44. Therefore, when the clutch C2 hydraulic pressure PRc2 increases rapidly, the shock generated by the sudden increase in the C2 hydraulic pressure PRc2 is easily transmitted to the transmission output shaft 36 via the third planetary gear set 46. In this way, when the CB hydraulic pressure PRcb of the speed change engagement device CB that separates or engages other rotating elements of the planetary gear device directly connected to the transmission output shaft 36 is rapidly pressurized, the impact generated by the rapid pressurization of the CB hydraulic pressure PRcb is easily transmitted to the transmission output shaft 36.

[0079] Therefore, when the slow-moving interrupt recovery condition is met and when the slow-moving interrupt control is restored from the slow-moving interrupt control (when the slow-moving interrupt is restored), if the C2 hydraulic pressure PRc2 of the engaged clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 are suddenly increased, the slow-moving interrupt recovery control unit 112 slowly increases the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 to reduce the impact generated when the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 are increased.

[0080] Whether or not to gradually increase the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 at the time of recovery from slow running interruption is determined based on whether all of the following conditions (c) to (e) are satisfied.

[0081] Condition (c) requires that the MG rotational speed Nm of the electric motor MG remains below a predetermined value α for a predetermined time tα or longer. In other words, condition (c) requires that the electric motor MG remains stopped for a predetermined time tα or longer. Condition (d) requires that the shift position of the automatic transmission 24 is N or P (i.e., the power transmission cutoff position). Condition (e) requires that the AT output shaft rotational speed No of the automatic transmission 24 is greater than zero.

[0082] Condition (c) will be explained. Condition (c) is defined to determine whether the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 are decreasing. The specified value α of the MG rotational speed Nm is determined in advance through experimentation or design and is set to a rotational speed that can be used to determine that the motor MG has stopped rotating. Determining that the motor MG has stopped rotating indicates that the mechanical hydraulic pump 58 is not discharging hydraulic fluid, i.e., that no hydraulic pressure is being supplied to the clutch C2 and brake B2. Furthermore, the specified time tα is determined in advance through experimentation or design and is set to a value that can be used to determine that the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 have decreased to a level that allows for determination that the clutch C2 and brake B2 have substantially disengaged. It should be noted that when condition (c) is not met, since the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 are maintained at relatively high hydraulic pressures, even if the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 are suddenly increased, the impact is small.

[0083] Condition (d) will now be explained. Condition (d) is a condition specified for determining whether or not to discharge hydraulic fluid from the electric hydraulic pump 60. In the vehicle 10, the electric hydraulic pump 60 is configured not to be driven when the automatic transmission 24 is in the N or P gear. Therefore, by determining whether the automatic transmission 24 is in the N or P gear, it is determined that the electric hydraulic pump 60 is not being driven, that is, that hydraulic fluid is not being discharged from the electric hydraulic pump 60. It should be noted that when condition (d) is not met, hydraulic fluid is discharged from the electric hydraulic pump 60, thereby suppressing a decrease in the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2. Therefore, when condition (d) is not met, even if the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 are suddenly increased, the shock is minimal. It should be noted that the electric hydraulic pump 60 is stopped when the automatic transmission 24 is in N gear and P gear in order to suppress the driving sound generated by driving the electric hydraulic pump 60 in N gear and P gear, and to suppress the increase in internal heat from the electric hydraulic pump 60 and the pump motor 62 due to the continuous driving of the electric hydraulic pump 60.

[0084] Condition (e) will be explained. Condition (e) is a condition specified to determine whether the transmission output shaft 36 is rotating. Therefore, condition (e) is determined, for example, based on whether the AT output shaft rotational speed No is greater than a specified value β. The specified value β is determined in advance through experimentation or design and is set as a threshold value that can be used to determine when the AT output shaft rotational speed No has stopped rotating. When the AT output shaft rotational speed No has stopped rotating, even if the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 are suddenly increased, there is little impact. In other words, if condition (e) does not hold, even if the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 are suddenly increased, the impact will be within the allowable range.

[0085] When executing slow-motion interruption recovery control, if all of the above conditions (c) through (e) are met, the control unit 112 determines that a condition that easily causes a shock during slow-motion interruption recovery control is met and slowly increases the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2. In other words, if none of the above conditions (c) through (e) are met during slow-motion interruption recovery control, the control unit 112 outputs a command to quickly increase the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2, to ensure that the shock caused by a sudden increase in the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 is within an allowable range. It should be noted that the above conditions (c) through (e) correspond to the prescribed conditions of the present invention that easily cause a shock during the transition period to recovery from slow-motion control.

[0086] When all of the above conditions (c) to (e) are met, the crawling interruption recovery control unit 112 controls the C2 indicated pressure PRc2i, which indicates the C2 hydraulic pressure PRc2 of clutch C2, and the B2 indicated pressure PRb2i, which indicates the B2 hydraulic pressure PRb2 of brake B2, to predetermined packing end pressures PRc2pac and PRb2pac, respectively. The control then executes sweep control to gradually increase the C2 indicated pressure PRc2i and the B2 indicated pressure PRb2i according to predetermined increasing gradients δc2 and δb2, respectively. It should be noted that the packing end pressure PRc2pac is determined in advance through experimentation or design and is the hydraulic pressure that brings clutch C2 to a state immediately before outputting torque capacity. The packing end pressure PRb2pac is determined in advance through experimentation or design and is the hydraulic pressure that brings brake B2 to a state immediately before outputting torque capacity. Furthermore, the increasing gradient δc2 is determined in advance through experimentation or design and is set to a threshold value such that the shock generated when increasing the C2 hydraulic pressure PRc2 of clutch C2 falls within an allowable range. The increasing gradient δb2 is determined in advance through experiments or design, and is set to a threshold value of the gradient such that a shock generated when the B2 hydraulic pressure PRb2 of the brake B2 is increased falls within an allowable range.

[0087] On the other hand, if none of the above conditions (c) to (e) are met, the slow travel interruption recovery control unit 112 controls the C2 command pressure PRc2i of clutch C2 and the B2 command pressure PRb2i of brake B2 so as to rapidly increase the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2. For example, the slow travel interruption recovery control unit 112 sets the C2 command pressure PRc2i to the predetermined rated pressure PRc2con that causes clutch C2 to be engaged. Similarly, the slow travel interruption recovery control unit 112 sets the B2 command pressure PRb2i to the predetermined rated pressure PRb2con that causes brake B2 to be engaged. In this way, by changing the indicated pressures PRc2i and PRb2i in a step-by-step manner, the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 are rapidly increased following the indicated pressures PRc2i and PRb2i. However, since this is performed under a state where none of the above conditions (c) to (e) are met, the impact caused by the rapid increase in the C2 hydraulic pressure PRc2 and the B2 hydraulic pressure PRb2 is within the allowable range.

[0088] Figure 4 This flowchart explains the main part of the control operation of the electronic control device 100. Specifically, it explains the control operation that can suppress the shock generated during the transition period of returning from the slow-run interruption control. This flowchart is repeatedly executed during the execution of the slow-run interruption control.

[0089] First, in step S10 (hereinafter omitted), which corresponds to the control function of the slow-motion interruption recovery control unit 112, it is determined whether the slow-motion interruption recovery conditions for resuming from slow-motion interruption control are met. If the determination in S10 is negative, this routine ends. If the determination in S10 is positive, in step S20, which corresponds to the control function of the slow-motion interruption recovery control unit 112, it is determined whether the conditions for gradually increasing the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 are met. Specifically, it is determined whether all of the above-mentioned conditions (c) to (e) are met.

[0090] If the determination in S20 is yes, upon resumption of the slow-running interruption control, the electric hydraulic pump 60 (EOP) is rapidly driven to control the C2 command pressure PRc2i of clutch C2 and the B2 command pressure PRb2i of brake B2 to the holding end pressures PRc2pac and PRb2pac, respectively. The C2 command pressure PRc2i of clutch C2 is then controlled to increase according to an increasing gradient δc2, while the B2 command pressure PRb2i of brake B2 is controlled to gradually increase according to an increasing gradient δb2 (sweep control). At this time, by increasing the MG rotational speed Nm of the electric motor MG after a predetermined time tx has passed since the resumption of the slow-running interruption control, the C2 hydraulic pressure PRc2 and the B2 hydraulic pressure PRb2 can be gradually increased using the hydraulic pressure of the working fluid discharged from the mechanical hydraulic pump 58 as the initial pressure. As a result, the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 gradually increase following the preset rising gradients δc2 and δb2, thereby reducing the shock generated in clutch C2 and brake B2. Furthermore, by driving the electric hydraulic pump 60 from the time when the slow-running interruption control is resumed, the C2 hydraulic pressure PRc2 and the B2 hydraulic pressure PRb2 can be quickly adjusted to their respective indicated pressures PRc2i and PRb2i.

[0091] On the other hand, if the determination in S20 is negative, upon resuming from the slow-running interruption control, the electric hydraulic pump 60 (EOP) is rapidly driven to set the C2 command pressure PRc2i of clutch C2 and the B2 command pressure PRb2i of brake B2 to the rated pressures PRc2con and PRb2con, respectively, which engage clutch C2 and brake B2. As a result, the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 are controlled to be rapidly increased toward their respective rated pressures PRc2con and PRb2con, thereby improving responsiveness when resuming the slow-running control state. Furthermore, even if the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 are rapidly increased in S40, the resulting shock remains within an acceptable range.

[0092] Figure 5 It is a timing diagram for illustrating the control state of the electronic control device 100, and is a timing diagram for illustrating the control work when the automatic transmission 24 is in N gear and the vehicle speed V is greater than zero (that is, the AT output shaft rotation speed No is greater than zero) when recovering from the slow-run interruption control.

[0093] exist Figure 5 In the figure, the horizontal axis represents the elapsed time t [msec], and the vertical axis represents the shift position of the automatic transmission 24, the EOP control signal Seop, the vehicle acceleration G [m / s 2 ], various rotational speeds (turbine rotational speed Nt, MG rotational speed Nm, AT output shaft rotational speed No), and B2 hydraulic pressure PRb2 of brake B2. Figure 5 The illustrated embodiment shows a case where the shift position of the automatic transmission 24 is N, the AT output shaft rotation speed No is greater than zero, and the MG rotation speed Nm is zero for a predetermined time tα when the vehicle is restored from the slow-running interruption control. Figure 5 Although the C2 hydraulic pressure PRb2 of the clutch C2 is not described in the timing chart of , the C2 hydraulic pressure PRc2 is also controlled in the same manner as the brake B2.

[0094] exist Figure 5At time t1 shown, when the slow-run interruption recovery conditions are met, slow-run interruption recovery control begins. At this point, the electric hydraulic pump 60 begins operating at time t1. Furthermore, after the brake B2 command pressure PRb2i is set to the brake B2 hold end pressure PRb2pac, it gradually increases according to a predetermined increase gradient δb2. Conversely, as the electric hydraulic pump 60 is driven, the B2 hydraulic pressure PRb2 increases slightly, following the B2 command pressure PRb2i from time t1. At time t2, a predetermined time tx after time t1, the MG rotational speed Nm begins to increase, as shown by the solid line. After time t2, as the MG rotational speed Nm increases, the mechanical hydraulic pump 58 is driven, discharging hydraulic fluid from the mechanical hydraulic pump 58. At time t3, the turbine rotational speed Nt, shown by the dashed line, begins to increase, driven by the MG rotational speed Nm. In this way, when recovering from the slow-run interruption control, the B2 hydraulic pressure PRb2 of the brake B2 is gradually increased, thereby reducing the impact generated when the B2 hydraulic pressure PRb2 is pressurized, and suppressing the impact caused by the impact being transmitted to the transmission output shaft 36 side (specifically, the change in vehicle acceleration G).

[0095] here, Figure 5 The B2 instruction pressure PRb2ix of the brake B2 shown by the two-dot chain line corresponds to the case where the B2 hydraulic pressure PRb2 of the brake B2 is rapidly increased to the rated pressure PRb2con for engaging the brake B2. Figure 5 As shown, at time t2, the B2 command pressure PRb2ix of brake B2 is increased stepwise to the rated pressure PRb2con, which engages brake B2. In this case, the B2 hydraulic pressure PRb2 of brake B2 is rapidly increased to follow the command pressure PRb2ix. As a result, the vehicle acceleration G fluctuates as shown by the dotted line, causing a shock.

[0096] As described above, according to this embodiment, when resuming from slow-running interruption control to slow-running control, hydraulic pressure is ensured by driving the electric hydraulic pump 60 immediately after the start of resuming slow-running control, prior to the increase in the MG rotational speed Nm of the electric motor MG. Furthermore, hydraulic pressure is ensured by the mechanical hydraulic pump 58 by driving the mechanical hydraulic pump 58 thereafter as the MG rotational speed Nm of the electric motor MG increases. This allows the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 to track the indicated pressures PRc2i and PRb2i, respectively, thereby suppressing the shock caused by a sudden increase in the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2.

[0097] Furthermore, according to this embodiment, when returning to creep control, if conditions that easily cause a shock during the transition period of return are met, control is performed so that the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 are gradually increased. This reduces the shock that occurs when the C2 hydraulic pressure PRc2 and the B2 hydraulic pressure PRb2 are increased. Consequently, the shock that occurs during the transition period of return to creep control can be suppressed.

[0098] As mentioned above, although the embodiment of the present invention is described in detail based on the drawings, the present invention can also be applied in other aspects.

[0099] For example, in the aforementioned embodiment, the automatic transmission 24 is configured with four first to fourth planetary gear sets 42 to 48, clutches C1 to C4, brakes B1, and brake B2. However, the present invention is not limited to this configuration. In short, the present invention can be appropriately applied to any stepped transmission that includes multiple speed-changing engagement devices CB and can establish multiple speed stages based on the combination of these engagement devices CB. Furthermore, the number of speed stages in a stepped transmission is not limited to ten and can be varied as appropriate.

[0100] In addition, in the aforementioned embodiment, during the slow-run interruption recovery control, whether to slowly increase the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 is determined based on whether the AT output shaft rotation speed No is greater than zero, but instead of this, whether to slowly increase the C2 hydraulic pressure PRc2 of the clutch C2 and the B2 hydraulic pressure PRb2 of the brake B2 is determined based on whether the turbine rotation speed Nt is greater than zero.

[0101] Furthermore, in the aforementioned embodiment, the C2 hydraulic pressure PRc2 of clutch C2 and the B2 hydraulic pressure PRb2 of brake B2 are gradually increased in situations where a shock is likely to occur during slow-running interruption recovery control. However, the engagement pressure of either clutch C2 or brake B2 may also be gradually increased. For example, by setting the clutch C2 engagement rated pressure PRc2con to a relatively low pressure, the impact of a sudden increase in the C2 hydraulic pressure PRc2 of clutch C2 is minimal. In this case, only the B2 hydraulic pressure PRb2 of brake B2 is gradually increased.

[0102] Furthermore, in the aforementioned embodiment, the clutch C2 and brake B2 of the automatic transmission 24 are engaged during creep control. However, this is not necessarily limited to the clutch C2 and brake B2. In other words, the shift engagement device CB to be engaged can be appropriately changed within the range in which power transmission of the automatic transmission 24 is interrupted.

[0103] It should be noted that the above-mentioned content is merely one embodiment, and the present invention can be implemented in various forms with various changes and improvements added based on the knowledge of those skilled in the art.

Claims

1. A vehicle control device suitable for a vehicle comprising: a driving force source including at least an electric motor; a stepped transmission having a plurality of engagement devices capable of forming a plurality of gear stages according to a combination of the engagement devices being engaged; a mechanical hydraulic pump driven by power output from the electric motor; and an electric hydraulic pump; the vehicle control device is capable of executing a slow-moving control and a slow-moving interruption control, wherein in the slow-moving control, a predetermined engagement device is engaged within a range in which power transmission of the stepped transmission is cut off and a slow-moving torque is output from the electric motor to the stepped transmission, and in the slow-moving interruption control, the slow-moving control is terminated and the rotation of the electric motor is stopped. The vehicle control device is characterized in that: When a return condition from the slow motion interruption control to the slow motion control is satisfied, the rotation speed of the electric motor is increased after the electric hydraulic pump is driven.

2. The vehicle control device according to claim 1, wherein: When the return condition is satisfied and a predetermined condition that easily generates a shock during the transition period of return to the creep control is satisfied, the engagement pressure of the engagement device is controlled to gradually increase.

3. The vehicle control device according to claim 2, characterized in that: The prescribed conditions are that all of the following conditions are met: the rotation speed of the output shaft of the step-variable transmission is greater than zero; the motor stops rotating for a predetermined time or longer; and the shift position of the step-variable transmission is a power transmission cutoff position.

4. The vehicle control device according to any one of claims 1 to 3, characterized in that: The restoration condition includes a vehicle speed being greater than zero during the creep interruption control.

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