Vehicle control device

Abstract

To provide a vehicle control device capable of preventing an engine failure while ensuring response to shift operation after an engine is started up under cold temperature.SOLUTION: An electronic control device 90 of a vehicle 10 comprises: (a) an engaging device control section 98c which starts engagement control to switch a brake B2 varying an engine rotation speed Ne to an engaged state and executes control to maintain a brake B1 and clutches C1, C3 and C4 (second engagement devices) to be in a released state when engine torque Te is in a state of being transmitted to an AT input shaft 26 which is an input shaft of an automatic transmission 28, and an oil temperature THoil of work fluid OIL controlling an operation state of a brake B2 (a predetermined engaging device) is within a predetermined low temperature range, in a case where the brake is switched to the engaged state before a non-travel range is switched to a travel range; and (b) a torque up control section 98d which executes torque up control to make the engine torque Te larger than the engine torque before starting the engagement control while the engagement control of the brake B2 is in execution.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle equipped with an engine and a planetary gear type automatic transmission. [Background technology]

[0002] There are known control devices for vehicles equipped with an engine and a planetary gear type automatic transmission. For example, there is a control device for a vehicle described in Patent Document 1. The control device for a vehicle described in Patent Document 1 discloses that, in order to ensure responsiveness to a shift operation after starting the engine at low temperatures (=suppressing a decrease in responsiveness), some of a plurality of friction engagement devices that are to be in an engaged state in the driving range are engaged in advance before switching from the non-driving range to the driving range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-17822 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the vehicle control device described in Patent Document 1, when some of the friction engagement devices (particularly the brakes) are engaged at low temperatures, the hydraulic oil has a high viscosity, so that the friction engagement devices drag the hydraulic oil, causing rotation fluctuations in the automatic transmission. This rotation fluctuation in the automatic transmission reduces the engine speed, which may cause the engine to stall (hereinafter referred to as "stalling").

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that can suppress the occurrence of engine stalls while ensuring responsiveness to shift operations after engine start at low temperatures. [Means for solving the problem]

[0006] The gist of a first invention is a control device for a vehicle, the control device comprising: an engine; and a planetary gear type automatic transmission provided in a power transmission path between the engine and drive wheels and having a plurality of hydraulic friction engagement devices, the plurality of friction engagement devices including a first engagement device and a plurality of second engagement devices, the automatic transmission being placed in a neutral state when the second engagement device is in a disengaged state, and when a gear stage in a driving range is formed, at least some of the second engagement devices and the first engagement device are all in an engaged state, the control device comprising: (a) an output torque of the engine is adjusted to a torque of the automatic transmission; The present invention has (a) an engagement device control unit that, when the hydraulic oil is in a state transmitted to the input shaft and the temperature of the hydraulic oil controlling the operating state of the first engagement device is within a predetermined low temperature range, initiates engagement control to switch a predetermined engagement device among the first engagement devices, which fluctuates the rotational speed of the engine, to an engaged state when switched to an engaged state before switching from a non-driving range to the driving range, and executes control to maintain the second engagement device in a released state; and (b) a torque-up control unit that, during execution of the engagement control, executes torque-up control to increase the output torque of the engine compared to before the start of the engagement control.

[0007] The gist of the second invention is that in the first invention, the torque-up control unit executes the torque-up control during a period in which the specified engagement device is in a semi-engaged state while the engagement control is being executed.

[0008] The gist of the third invention is that in the first or second invention, the torque-up control unit executes the torque-up control during a packing period of the specified engagement device while the engagement control is being executed.

[0009] The gist of a fourth invention is that in any one of the first to third inventions, an increase in the output torque of the engine in the torque-boost control is set in accordance with the oil temperature.

[0010] The gist of the fifth invention is that in any one of the first to fourth inventions, when the non-driving range is switched to the driving range while the torque-up control is being executed, the torque-up control unit gradually reduces the amount of increase in the output torque of the engine in the torque-up control.

[0011] The gist of the sixth invention is that in any one of the first to fifth inventions, when the engine rotation speed becomes equal to or higher than a predetermined rotation speed as a result of execution of the torque-up control, the torque-up control unit gradually reduces the amount of increase in the output torque of the engine in the torque-up control.

[0012] The gist of the seventh invention is that in any one of the first to sixth inventions, when a start switch that starts the engine is in an on state, the engagement device control unit executes the engagement control and the torque-up control unit executes the torque-up control, and when the start switch is in an off state, the engagement device control unit does not execute the engagement control and the torque-up control unit does not execute the torque-up control. Effect of the Invention

[0013] According to the vehicle control device of the first invention, (a) an engagement device control unit that starts engagement control for switching a predetermined engagement device that fluctuates the rotation speed of the engine when the first engagement device is switched to an engaged state before switching from a non-driving range to the driving range and executes control to maintain the second engagement device in a released state when the output torque of the engine is transmitted to the input shaft of the automatic transmission and the temperature of the hydraulic oil that controls the operating state of the first engagement device is within a predetermined low temperature range, and (b) a torque-up control unit that executes torque-up control to increase the output torque of the engine compared to before the start of the engagement control during the execution of the engagement control. When the oil temperature of the hydraulic oil is within a predetermined low temperature range, the engagement control for switching the predetermined engagement device to an engaged state is started before switching from the non-driving range to the driving range, thereby ensuring responsiveness to a shift operation after engine start, and the torque-up control for increasing the output torque of the engine is executed, thereby suppressing the occurrence of stalling due to rotation fluctuations in the automatic transmission.

[0014] According to the vehicle control device of the second aspect of the invention, in the first aspect of the invention, the torque-boost control unit executes the torque-boost control during a period in which the predetermined engagement device is in a half-engaged state while the engagement control is being executed. Since the torque-boost control is executed during a period in which the predetermined engagement device is in a half-engaged state while the engagement control is being executed, the occurrence of an engine stall due to a rotational fluctuation in the automatic transmission during this period is suppressed.

[0015] According to the vehicle control device of the third aspect of the invention, in the first or second aspect of the invention, the torque-boost control unit executes the torque-boost control during a packing period of the predetermined engagement device while the engagement control is being executed. Since the torque-boost control is executed during a packing period of the predetermined engagement device while the engagement control is being executed, the occurrence of an engine stall due to a rotational fluctuation in the automatic transmission during this period is suppressed.

[0016] According to the vehicle control device of the fourth aspect of the invention, in any one of the first to third aspects of the invention, the increase in the output torque of the engine in the torque-boost control is set according to the oil temperature. Rotation fluctuations (amount of fluctuation per time) in the automatic transmission change according to the oil temperature. Since the increase in the output torque of the engine in the torque-boost control is set according to the oil temperature, it is possible to reduce the increase in the output torque of the engine for suppressing the occurrence of engine stalls caused by rotation fluctuations in the automatic transmission, compared to a case where the increase is not set according to the oil temperature. This suppresses an increase in fuel efficiency.

[0017] According to the vehicle control device of the fifth aspect of the invention, in any one of the first to fourth aspects of the invention, when the non-driving range is switched to the driving range while the torque-boost control is being performed, the torque-boost control unit gradually reduces the increase in the engine output torque in the torque-boost control. When the range is switched to the driving range, the engine output torque is increased accordingly, so the increase in the engine output torque in the torque-boost control may be zero. By gradually reducing the increase in the engine output torque in the torque-boost control, the discomfort felt by the driver due to the decrease in the drive torque transmitted to the drive wheels is reduced, compared to when the increase in the engine output torque in the torque-boost control is instantly reduced.

[0018] According to the vehicle control device of the sixth aspect of the invention, in any one of the first to fifth aspects of the invention, when the engine rotation speed becomes equal to or higher than a predetermined rotation speed as a result of the execution of the torque-boost control, the torque-boost control unit gradually reduces the increase in the output torque of the engine in the torque-boost control. When the engine rotation speed becomes equal to or higher than a predetermined rotation speed as a result of the execution of the torque-boost control (for example, when the engine revs up), the increase in the output torque of the engine in the torque-boost control is gradually reduced, thereby eliminating the revs up of the engine.

[0019] According to the vehicle control device of the seventh aspect of the invention, in any one of the first to sixth aspects of the invention, when a start switch for starting the engine is in an on state, the engagement device control section executes the engagement control and the torque-up control section executes the torque-up control, and when the start switch is in an off state, the engagement device control section does not execute the engagement control and the torque-up control section does not execute the torque-up control. When the start switch is in an off state, control for stopping the engine is executed, so there is no need to suppress the occurrence of an engine stall. Therefore, when the engagement control by the engagement device control section and the torque-up control by the torque-up control section are not executed when the start switch is in an off state, the engine is stopped more quickly than in other cases. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and is also a functional block diagram showing essential parts of control functions for various controls in the vehicle. [Diagram 2] FIG. 2 is a diagram illustrating a schematic configuration of the automatic transmission shown in FIG. [Diagram 3] 3 is an operation engagement table illustrating the relationship between the gear shift operation of the automatic transmission shown in FIG. 2 and combinations of operating states of engagement devices used therein. [Figure 4] 2 is an example of a flowchart illustrating a control operation of the electronic control device shown in FIG. 1. [Diagram 5] 5 is an example of a time chart when the flowchart of FIG. 4 is executed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of each part are not necessarily drawn accurately. In addition, in this specification, in the clutch K0 and the multiple shift engagement devices CB, when there is no particular distinction between a "fully engaged state" and a "half-engaged state (slip state)", the "engaged state" means a "fully engaged state". EXAMPLES

[0022] FIG. 1 is a schematic diagram of a vehicle 10 according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of control functions for various controls in the vehicle 10. As shown in FIG.

[0023] The vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which are driving power sources PG for traveling, and a power transmission device 16 provided on a power transmission path PT between the engine 12 and driving wheels 14. The vehicle 10 also includes an auxiliary battery 40, a starter relay 42, a starter motor 44, an engine control device 50, an EOP drive device 52, an EOP 54, a main battery 56, an inverter 58, a hydraulic control circuit 60, a shift lever 84, an ignition switch 88, and an electronic control device 90.

[0024] The power transmission device 16 includes, in order from the engine 12 side, an engine connecting shaft 20, a clutch K0, an electric motor connecting shaft 22, a torque converter 24, an AT input shaft 26 which is an input rotating member of the automatic transmission 28, and the automatic transmission 28, within a case 18 which is a non-rotating member attached to the vehicle body. The power transmission device 16 also includes a differential 32 which is connected to an AT output shaft 30 which is an output rotating member of the automatic transmission 28, a pair of axles 34 which are connected to the differential 32, and the like.

[0025] The engine 12 is a well-known internal combustion engine. An electronic control device 90 (described later) controls an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, and the like provided in the vehicle 10, thereby controlling the engine torque Te [Nm] outputted from the engine 12. In this specification, the terms torque, driving force, power, and force (power) are synonymous unless otherwise specified.

[0026] The starter motor 44 is a DC motor that is rotated by power stored in, for example, the auxiliary battery 40 via a starter relay 42 to crank the engine 12 and bring it into operation.

[0027] The engine connecting shaft 20 is a member that connects the engine 12 and the clutch K0, and is, for example, a crankshaft.

[0028] The electric motor MG is a so-called motor generator having a function as an electric motor that generates mechanical power from electric energy (electric motor function) and a function as a generator that generates electric energy from mechanical power (generator function). The electric motor MG is connected to a power transmission path PT so as to be capable of transmitting power. The electric motor MG has an inverter 58 controlled by an electronic control device 90, which will be described later, to control the MG torque Tmg [Nm], which is the output torque of the electric motor MG.

[0029] The electric motor MG is supplied with electric power stored in the main battery 56 via the inverter 58 and is rotated to output, for example, a driving force for running the vehicle 10, or generates electric power by converting a driving force input from the engine 12 via the clutch K0 or a driven force input from the drive wheels 14 side into electric power. The generated electric power is charged into the main battery 56 via the inverter 58. The main battery 56 is an electric storage device that supplies and receives electric power to the electric motor MG.

[0030] The inverter 58 is provided between the electric motor MG and the main battery 56, and is a power supply circuit that is controlled by the electronic control device 90 to convert DC to AC and vice versa.

[0031] The clutch K0 is a friction engagement device that connects and disconnects the power transmission between the engine connecting shaft 20 connected to the engine 12 and the electric motor connecting shaft 22 connected to the rotor of the electric motor MG, and is, for example, a wet-type multi-plate hydraulic friction engagement device.

[0032] The torque converter 24 is a well-known torque converter including a pump wheel connected to the electric motor connecting shaft 22, a turbine wheel connected to the AT input shaft 26, and a lock-up clutch LU that directly connects the pump wheel and the turbine wheel. The torque converter 24 is a fluid-type power transmission device that can transmit the driving force for traveling output from the driving force source PG to the AT input shaft 26 via a fluid. The vehicle 10 is equipped with a MOP 36 that is a mechanical oil pump. The MOP 36 is connected to the pump wheel and is driven to rotate by the driving force source PG (the engine 12, the electric motor MG) to discharge hydraulic oil OIL used in each part in the case 18. The hydraulic oil OIL is a hydraulic oil for an automatic transmission, such as ATF (Automatic Transmission Fluid), and is used as a hydraulic oil for a hydraulic actuator provided to perform shift control of the automatic transmission 28 and control the engagement and disengagement of the clutch K0, and is also used as a cooling oil and lubricating oil supplied to various parts inside the case 18, such as the torque converter 24 and the automatic transmission 28.

[0033] The EOP 54 is a well-known electric oil pump that is driven by an EOP drive device 52 including an EOP drive motor (not shown) and thereby discharges hydraulic oil OIL used in various parts inside the case 18. The EOP drive device 52 is driven using power stored in the auxiliary battery 40. The EOP 54 can be driven as much as necessary when necessary. For example, the EOP 54 can be driven by the EOP drive device 52 at any timing and for any period of time, independent of the rotation of the engine 12 and the electric motor MG. The type of the EOP drive motor is not particularly limited as long as it can drive the EOP 54, and is, for example, a three-phase brushless DC motor.

[0034] The automatic transmission 28 is a planetary gear type stepped transmission provided in the power transmission path PT, has a plurality of shift engagement devices CB, and performs so-called clutch-to-clutch shifting by switching one of the plurality of shift engagement devices CB. The plurality of shift engagement devices CB are hydraulic friction engagement devices such as clutches C1 to C4 and brakes B1 to B2 (see FIG. 2). The automatic transmission 28 selectively establishes one of a plurality of shift stages (=gear stages) by clutch-to-clutch shifting, thereby shifting the rotation of the AT input shaft 26 and outputting it from the AT output shaft 30. The automatic transmission 28 can also be in a neutral state. The AT input shaft 26 is also a turbine shaft that is rotationally driven by a turbine wheel of the torque converter 24. In the automatic transmission 28, a predetermined gear stage is established according to the driver's accelerator operation, vehicle speed V [km / h], etc., by engagement / disengagement control that controls the operating state (engaged state or disengaged state) of each of the multiple shift engagement devices CB. The AT input shaft 26 corresponds to the "automatic transmission input shaft" in this invention. The multiple shift engagement devices CB correspond to the "multiple friction engagement devices" in this invention.

[0035] FIG. 2 is a diagram for explaining a schematic configuration of the automatic transmission 28 shown in FIG. 1. The automatic transmission 28 is configured approximately symmetrically with respect to a rotation axis common to the AT input shaft 26 and the AT output shaft 30, and in FIG. 2, the lower half with respect to the rotation axis is omitted. FIG. 3 is an operation engagement table for explaining the relationship between the shift operation of the automatic transmission 28 shown in FIG. 2 and the combination of the operation states of the engagement devices used therein. In FIG. 3, "◯" represents "engaged state", "△" represents "either engaged or disengaged state is possible", and "blank" represents "disengaged state". The automatic transmission 28 shifts the rotation of the AT input shaft 26 connected to the turbine shaft of the torque converter 24 in multiple stages and outputs it from the AT output shaft 30. The automatic transmission 28 includes a plurality of planetary gear sets (planetary gear sets 62, 64, 66, 68) and a plurality of shift engagement devices CB, which are connected as shown in FIG. 2. The planetary gear devices 62, 66, and 68 are each a single-pinion type planetary gear device, and the planetary gear device 64 is a double-pinion type planetary gear device. The planetary gear device 62 and the planetary gear device 64 form a so-called Ravigneaux type planetary gear train. In the automatic transmission 28, one of ten forward gear stages (first gear stage "1st" to tenth gear stage "10th") with different gear ratios γat (=AT input shaft rotation speed Nin [rpm] / AT output shaft rotation speed Nout [rpm]) is formed by a combination of individually controlled engagement states and release states of the multiple shift engagement devices CB as shown in the operation engagement table of FIG. 3, or a reverse gear stage is formed. The AT input shaft rotation speed Nin is the rotation speed of the AT input shaft 26, and the AT output shaft rotation speed Nout is the rotation speed of the AT output shaft 30. The AT output shaft rotation speed Nout corresponds to the vehicle speed V.

[0036] When the automatic transmission 28 is switched from the non-driving range to the D range, for example, when the gear ratio γat of the D range is the largest, i.e., the lowest gear "1st" is formed, the brake B2 and the clutch C2 are both engaged. When the automatic transmission 28 is switched from the non-driving range to the R range, the brake B2 and the clutch C2 are both engaged. Regardless of the engagement and disengagement of the brake B2 and the clutch C2, when the brake B1 and the clutches C1, C3, and C4 are released, the automatic transmission 28 is in neutral. When the gear "1st" of the D range is formed, the clutch C1 is engaged, and when the transmission is switched to the R range, the clutch C3 is engaged. The brake B2 and the clutch C2 correspond to the "first engagement device" in the present invention, and the brake B1 and the clutches C1, C3, and C4 correspond to the "plurality of second engagement devices" in the present invention. When the automatic transmission 28 is switched from the non-driving range to the D range to form the "1st" gear range, the clutch C1 corresponds to "at least a part of the second engagement devices" in the present invention, and when the automatic transmission 28 is switched from the non-driving range to the R range, the clutch C3 corresponds to "at least a part of the second engagement devices" in the present invention.

[0037] Each of the multiple gear shift engagement devices CB is a known hydraulic friction engagement device, and is configured, for example, by a wet multi-plate clutch or brake pressed by a hydraulic actuator, a band brake tightened by a hydraulic actuator, etc. The multiple gear shift engagement devices CB are each controlled for engagement and release by a hydraulic control circuit 60, and the torque capacity, i.e., the engagement force, of each is changed, for example, continuously by pressure adjustment of a linear solenoid valve or the like within the hydraulic control circuit 60, to selectively connect members on both sides between which they are inserted.

[0038] Returning to FIG. 1, the differential 32 is a well-known differential that receives the driving force for traveling transmitted from the AT output shaft 30 of the automatic transmission 28 and transmits equal driving torque to a pair of axles 34 while allowing an appropriate difference in rotational speed.

[0039] The shift operation positions POSsh of the shift lever 84 are, for example, each of the operation positions of "P operation position", "R operation position", "N operation position", and "D operation position". The P operation position is a parking operation position that sets the automatic transmission 28 to the P range (= a range in which the automatic transmission 28 is in a neutral state and the AT output shaft 30 is mechanically fixed so as not to rotate). The R operation position is a reverse running operation position that sets the automatic transmission 28 to the R range (= a range that allows the vehicle 10 to run backwards). The N operation position is a neutral operation position that sets the automatic transmission 28 to the N range (= a range that is in a neutral state). The D operation position is a forward running operation position that sets the automatic transmission 28 to the D range (= a range that allows forward running by executing automatic shift control using all the gear stages of the automatic transmission 28). The automatic transmission 28 is switched to the P range, R range, N range, and D range, respectively, by the driver selecting each of the operation positions of "P operation position", "R operation position", "N operation position", and "D operation position". The P range and N range are non-driving ranges of the automatic transmission 28, and the R range and D range are driving ranges of the automatic transmission 28.

[0040] The hydraulic control circuit 60 uses the hydraulic pressure of the hydraulic oil OIL discharged from the MOP 36 and the EOP 54 as the source pressure and supplies the necessary hydraulic oil OIL to each part in the case 18. For example, the hydraulic control circuit 60 generates hydraulic pressure for controlling the engagement and disengagement of the clutch K0, hydraulic pressure for controlling the shifting of the automatic transmission 28, and hydraulic pressure for controlling the engagement and disengagement of the lock-up clutch LU of the torque converter 24, and supplies these to each hydraulic actuator in the case 18.

[0041] When the clutch K0 is engaged, the driving force for traveling output from the engine 12 is transmitted from the engine connecting shaft 20 through the clutch K0, the electric motor connecting shaft 22, the torque converter 24, the automatic transmission 28, the differential 32, the axles 34, etc. in this order to the driving wheels 14. The driving force for traveling output from the electric motor MG is transmitted from the electric motor connecting shaft 22 through the torque converter 24, the automatic transmission 28, the differential 32, the axles 34, etc. in this order to the driving wheels 14, regardless of whether the clutch K0 is engaged or disengaged.

[0042] In the vehicle 10, for example, a drive mode in which the engine runs using only the engine 12 of the driving power sources PG as a drive source (hereinafter referred to as the "engine drive mode") and a drive mode in which the battery electric vehicle (BEV) runs using only the electric motor MG of the driving power sources PG as a drive source (hereinafter referred to as the "BEV drive mode") can be selected. In the engine drive mode, the clutch K0 is engaged.

[0043] The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 90 includes computers for engine control, electric motor control, hydraulic control, etc. as necessary. The electronic control device 90 corresponds to the "control device" in this invention.

[0044] The electronic control device 90 receives various signals based on detection values ​​from various sensors provided in the vehicle 10 (for example, an engine rotation speed sensor 70, a turbine rotation speed sensor 72, an output rotation speed sensor 74, a MG rotation speed sensor 76, an accelerator opening sensor 78, a throttle valve opening sensor 80, a battery sensor 82, a shift position sensor 86, an ignition switch 88, etc.) (for example, an engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, a turbine rotation speed Nt [rpm] which is the same value as the AT input shaft rotation speed Nin [rpm], an AT output shaft rotation speed Nout [rp] which corresponds to the vehicle speed V, The input signals include the vehicle speed (vehicle speed), the MG rotation speed Nmg [rpm] which is the rotation speed of the electric motor MG, the accelerator opening θacc [%] which is the amount of accelerator operation by the driver which indicates the magnitude of the driver's acceleration operation, the throttle valve opening θth [%] which is the opening of the electronic throttle valve, the battery temperature THbat [°C], the battery charge / discharge current Ibat [A] and the battery voltage Vbat [V] of the main battery 56, the shift operation position POSsh which indicates the operation position of the shift lever 84 operated by the driver, and the engine start signal IG which indicates whether the ignition switch 88 has been operated by the driver. The ignition switch 88 corresponds to the "start switch" in this invention.

[0045] The electronic control device 90 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, an MG control signal Smg for controlling the electric motor MG via the inverter 58, a shift control signal Sat for controlling a plurality of shift engagement devices CB, a K0 control signal Sk0 for controlling the clutch K0, an LU control signal Slu for controlling the lock-up clutch LU, an EOP control signal Seop for controlling the EOP 54, etc.) to each device (e.g., the engine control device 50, the inverter 58, the hydraulic control circuit 60, the EOP drive device 52, etc.) provided in the vehicle 10.

[0046] The electronic control device 90 functionally comprises a drive source control unit 92, a K0 clutch control unit 94, a gear shift control unit 96, and a pre-range switching control unit 98.

[0047] The drive source control unit 92 functionally comprises an engine control unit 92a that controls the operation of the engine 12, and an electric motor control unit 92b that controls the operation of the electric motor MG via the inverter 58, and these control functions are used to perform driving in the engine driving mode or the BEV driving mode.

[0048] The drive source control unit 92 calculates the driver's required drive amount (e.g., required drive torque Trdem [Nm]) for the vehicle 10 by applying the actual accelerator opening θacc and vehicle speed V to a required drive amount map, for example. The required drive amount map is a map in which the relationship between the accelerator opening θacc and vehicle speed V and the required drive amount is determined in advance experimentally or by design and stored. The required drive amount is the drive amount required for the vehicle 10, for example, the required drive torque Trdem. In other words, the required drive torque Trdem is the required drive power Prdem [W] at the vehicle speed V at that time. As the required drive amount, the required drive force Frdem [N] at the drive wheels 14, the required output torque at the AT output shaft 30, etc. can also be used. In calculating the required drive amount, the AT output shaft rotation speed Nout, etc. may be used instead of the vehicle speed V. In this way, the required drive torque Trdem, the required drive power Prdem, the required drive force Frdem, and the required output torque at the AT output shaft 30 are the same in that they are the required drive amounts of the vehicle 10.

[0049] The drive source control unit 92 outputs an engine control signal Se for controlling the engine 12 and an MG control signal Smg for controlling the electric motor MG so as to realize the required drive power Prdem, taking into consideration the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 28, the chargeable power Win [W] and the dischargeable power Wout [W] of the main battery 56, etc. The engine control signal Se is, for example, a command value for the engine power Pe [W], which is the power of the engine 12 that outputs the engine torque Te at the engine rotation speed Ne at that time. The MG control signal Smg is, for example, a command value for the power consumption Wm [W] of the electric motor MG that outputs the MG torque Tmg at the MG rotation speed Nmg at that time.

[0050] The chargeable power Win of the main battery 56 is the maximum power that can be input, which specifies the limit on the input power of the main battery 56, and indicates the input limit of the main battery 56. The dischargeable power Wout of the main battery 56 is the maximum power that can be output, which specifies the limit on the output power of the main battery 56, and indicates the output limit of the main battery 56. The chargeable power Win and dischargeable power Wout of the main battery 56 are calculated by the electronic control device 90 based on, for example, the battery temperature THbat and the state of charge value SOC [%] of the main battery 56 (the ratio of the amount of charge actually stored to a predetermined full charge capacity).

[0051] For example, when the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the drive source control unit 92 sets the drive mode to the BEV driving mode. On the other hand, when the required drive torque Trdem cannot be satisfied only by the output of the electric motor MG, the drive source control unit 92 sets the drive mode to the engine driving mode. On the other hand, even when the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the drive source control unit 92 establishes the engine driving mode when the state of charge value SOC of the main battery 56 is less than a predetermined engine start threshold value or when the engine 12 or the like needs to be warmed up. The engine start threshold value is a predetermined threshold value for determining that the state of charge value SOC is at a value at which the engine 12 needs to be forcibly started and the main battery 56 needs to be charged.

[0052] The engine control unit 92a controls the engine torque Te to realize the drive demand amount for the vehicle 10. The electric motor control unit 92b controls the MG torque Tmg to realize the drive demand amount for the vehicle 10. Specifically, in the BEV driving mode, the electric motor control unit 92b controls the MG torque Tmg to realize the required drive torque Trdem. In the engine driving mode, the engine control unit 92a controls the engine torque Te to realize the entire required drive torque Trdem.

[0053] The K0 clutch control unit 94 controls the engagement and disengagement of the clutch K0 during engine running and BEV running. For example, the K0 clutch control unit 94 controls the clutch K0 to an engaged state during engine running and to a released state during BEV running. When the engine 12 is started in the engine running mode, the K0 clutch control unit 94 controls the clutch K0 to be in a fully engaged state via a half-engaged state in order to transmit the engine torque Te to the electric motor connecting shaft 22 after the engine 12 has fully exploded and become capable of self-sustaining operation.

[0054] The shift control unit 96 judges whether or not to shift the automatic transmission 28 by using, for example, a shift map, and outputs a shift control signal Sat for executing shift control as necessary to the hydraulic control circuit 60. The shift map is a predetermined relationship having a shift line for judging whether or not to shift the automatic transmission 28 on a two-dimensional coordinate system having, for example, vehicle speed V and required driving torque Trdem as variables. In the shift map, the AT output shaft rotation speed Nout or the like may be used instead of the vehicle speed V, and the required driving force Frdem, accelerator opening θacc, throttle valve opening θth or the like may be used instead of the required driving torque Trdem.

[0055] The drive source control unit 92 further functionally includes a starter control unit 92c. The starter control unit 92c executes engine start control for cranking the engine 12 using the starter motor 44 as necessary to operate the engine 12. The starter control unit 92c also controls the start timing of fuel supply to the engine 12 and ignition, etc., in conjunction with the cranking of the engine 12 by the starter motor 44. Note that the "engine start control" referred to here not only refers to the period from when the engine 12 completely explodes (starts operation) until it can operate independently, but also refers to a series of control operations related to engine start until the clutch K0 described later is fully engaged and the engine torque Te is output from the engine 12 to the AT input shaft 26.

[0056] From here, a case will be described in which the automatic transmission 28 is switched from the non-driving range to the driving range (e.g., D range) in a state in which the ignition switch 88 is in an activated state (on state), the engine 12 is in an operating state in the engine driving mode, the clutch K0 is in an engaged state, and the engine torque Te is transmitted to the electric motor connecting shaft 22. Here, before the automatic transmission 28 is switched from the non-driving range to the driving range, the engine torque Te transmitted to the electric motor connecting shaft 22 is, for example, when the engine 12 is in an idling state, and is an idling torque Teidle [Nm] that allows the engine 12 to idle while rotating and driving the MOP 36. After the automatic transmission 28 is switched from the non-driving range to the driving range, the engine torque Te transmitted to the electric motor connecting shaft 22 is increased in order to drive the vehicle 10 in response to the switch to the driving range. For example, the engine torque Te is set to a creep torque for generating a creep phenomenon in which the vehicle 10 moves slowly while the accelerator opening θacc is kept at zero, ie, the accelerator is off.

[0057] The pre-range switching control section 98 functionally includes a range determination section 98a, an oil temperature determination section 98b, an engagement device control section 98c, and a torque-up control section 98d.

[0058] The range determination unit 98a determines whether or not the range is a non-driving range. For example, when the shift lever 84 is in the P operating position or the N operating position, it is determined that the range is a non-driving range. When the range determination unit 98a determines that the range is not a non-driving range, that is, when the range is determined to be a driving range, the gear shift control unit 96 controls the operation state of the multiple gear shift engagement devices CB according to the driving range. For example, when the range determination unit 98a determines that the automatic transmission 28 is in the D range, the gear shift control unit 96 controls the operation state of the multiple gear shift engagement devices CB to form the gear stage determined to be shifted using the above-mentioned gear shift map.

[0059] The oil temperature determination unit 98b determines whether the oil temperature THoil [°C] is less than or equal to the first determination temperature THoil_jdg1 [°C], and also determines whether the oil temperature THoil is greater than or equal to the second determination temperature THoil_jdg2 [°C] (<THoil_jdg1).

[0060] Incidentally, the viscosity of the hydraulic oil OIL increases as its oil temperature THoil decreases. For example, during the packing period of the brake B2 during the execution of control for switching the brake B2 from the released state to the engaged state (hereinafter referred to as "engagement control"), when the oil temperature THoil is in a predetermined low temperature range that is less than or equal to the first determination temperature THoil_jdg1 and greater than or equal to the second determination temperature THoil_jdg2, the viscosity of the hydraulic oil OIL is high, and the brake B2 slides the hydraulic oil OIL between its friction plates. Due to this sliding by the brake B2, the rotational speed of the ring gear of the planetary gear device 66 fluctuates. When the drive wheels 14 are not rotating and the AT output shaft 30 is not rotating, if the rotational speed of the ring gear of the planetary gear device 66 fluctuates, the rotational speed of the sun gear of the planetary gear device 66 (= the rotational speed of the sun gear of the planetary gear device 68) fluctuates, and further, the rotational speed of the carrier of the planetary gear device 68 (= the AT input shaft rotational speed Nin) fluctuates. Also, when the clutch C2 is in the engaged state, the fluctuation in the rotational speed of the sun gear of the planetary gear device 66 is transmitted to the sun gear of the planetary gear device 64 via the clutch C2, and thereby also the rotational speed of the carrier of the planetary gear device 64 (= the AT input shaft rotational speed Nin) fluctuates. Thus, due to the sliding by the brake B2, the AT input shaft rotational speed Nin fluctuates via the planetary gear devices 64, 66, and 68 within the automatic transmission 28. This fluctuation in the AT input shaft rotational speed Nin is consistent with an increase in the load torque on the engine 12. Therefore, when the oil temperature THoil is in the predetermined low temperature range, there is a possibility that the brake B2 slides the hydraulic oil OIL, causing the AT input shaft rotational speed Nin to fluctuate and resulting in an engine stall.

[0061] The first judgment temperature THoil_jdg1 and the second judgment temperature THoil_jdg2 are judgment temperatures of the oil temperature THoil that are experimentally or design-based and that satisfy the following conditions. When the oil temperature THoil is in a temperature range (i.e., a predetermined low temperature range) that is equal to or lower than the first judgment temperature THoil_jdg1 and equal to or higher than the second judgment temperature THoil_jdg2, dragging of the hydraulic oil OIL by the brake B2 occurs when the brake B2 is engaged before switching from the non-driving range to the driving range. However, the occurrence of an engine stall can be suppressed by increasing the engine torque Te compared to before the start of the engagement control of the brake B2 (in this embodiment, the idling state). When the oil temperature THoil is lower than the second judgment temperature THoil_jdg2 (i.e., lower than the predetermined low temperature range), the occurrence of an engine stall cannot be suppressed even if the engine torque Te is increased as in the case where the oil temperature THoil is in the predetermined low temperature range when the brake B2 is engaged before switching from the non-driving range to the driving range. The temperature range equal to or lower than the first judgment temperature THoil_jdg1 and equal to or higher than the second judgment temperature THoil_jdg2 corresponds to the "predetermined low temperature range" in the present invention.

[0062] When the range determination unit 98a determines that the range is the non-driving range and the oil temperature determination unit 98b determines that the oil temperature THoil is equal to or lower than the first determination temperature THoil_jdg1 and equal to or higher than the second determination temperature THoil_jdg2, the engagement device control unit 98c starts engagement control of the brake B2 and the clutch C2 before switching from the non-driving range to the driving range and executes control to maintain the brake B1 and the clutches C1, C3, and C4 in the released state. During execution of the engagement control of the brake B2 by the engagement device control unit 98c, the torque-up control unit 98d executes torque-up control to increase the engine torque Te during the packing period of the brake B2 compared to before the start of the engagement control of the brake B2. The torque increase requirement Teup [Nm], which indicates the magnitude of the engine torque Te increased in the torque-up control, is an increase in the engine torque Te that is required to be increased compared to before the start of the engagement control of the brake B2 so as not to cause the engine to stall before switching from the non-driving range to the driving range, and is an amount that is predetermined experimentally or by design. The brake B2 corresponds to the "predetermined engagement device" in this invention. The torque increase requirement Teup corresponds to the "increase in the engine output torque" in this invention.

[0063] When the engagement control of the brake B2 is started by the engagement device control unit 98c and the torque-up control is being executed by the engine control unit 92a, the range determination unit 98a determines whether or not the non-driving range has been switched to the driving range. When the range determination unit 98a determines that the non-driving range has been switched to the driving range, the shift control unit 96 controls the operation state of the multiple shift engagement devices CB according to the switched driving range. For example, when it is determined that the automatic transmission 28 has been switched from the non-driving range to the D range, the shift control unit 96 executes engagement control of the clutch C1 so as to form the first gear shift stage "1st" of the D range. For example, when it is determined that the automatic transmission 28 has been switched from the non-driving range to the R range, the shift control unit 96 executes engagement control of the clutch C3 so as to form the R range. In addition, in both cases of switching the automatic transmission 28 from the non-driving range to the D range and switching the automatic transmission 28 from the non-driving range to the R range, engagement control of the brake B2 and the clutch C2 has already been started by the engagement device control unit 98c before switching from the non-driving range to the driving range.

[0064] When the range determination unit 98a determines that the range is the non-driving range and the oil temperature determination unit 98b determines that the oil temperature THoil is less than the second judgment temperature THoil_jdg2, the oil temperature determination unit 98b repeatedly determines whether the oil temperature THoil is equal to or higher than the second judgment temperature THoil_jdg2. This determination is repeated until the oil temperature THoil becomes equal to or higher than the second judgment temperature THoil_jdg2.

[0065] When the range determination unit 98a determines that the range is the non-driving range and the oil temperature determination unit 98b determines that the oil temperature THoil exceeds the first determination temperature THoil_jdg1, the range determination unit 98a determines whether the range has been switched from the non-driving range to the driving range. When the range determination unit 98a determines that the range has been switched from the non-driving range to the driving range, the shift control unit 96 controls the operation state of the multiple shift engagement devices CB according to the switched driving range. For example, when it is determined that the automatic transmission 28 has been switched from the non-driving range to the D range, the shift control unit 96 executes engagement control of the brake B2 and the clutches C1 and C2, respectively, so as to form the first gear shift stage "1st" of the D range. For example, when it is determined that the automatic transmission 28 has been switched from the non-driving range to the R range, the shift control unit 96 executes engagement control of the brake B2 and the clutches C2 and C3, respectively, so as to form the R range.

[0066] Fig. 4 is an example of a flowchart illustrating the control operation of the electronic control device 90 shown in Fig. 1. The flowchart in Fig. 4 is repeatedly executed when the ignition switch 88 is turned on, the engine 12 is in operation in the engine driving mode, the clutch K0 is engaged, and the engine torque Te is transmitted to the electric motor connecting shaft 22.

[0067] First, in step S10 (hereinafter, step will be omitted) corresponding to the function of the range determination unit 98a, it is determined whether or not the range is a non-driving range. If the determination in S10 is negative, that is, if it is determined that the range is a driving range, the operation state of the multiple gear shift engagement devices CB is controlled according to the driving range in S130 corresponding to the function of the gear shift control unit 96.

[0068] If the determination in S10 is positive, then in S20, which corresponds to the function of the oil temperature determination unit 98b, it is determined whether the oil temperature THoil is equal to or lower than the first determination temperature THoil_jdg1. If the determination in S20 is positive, then in S30, which corresponds to the function of the oil temperature determination unit 98b, it is determined whether the oil temperature THoil is equal to or higher than the second determination temperature THoil_jdg2.

[0069] If the determination in S30 is positive, in S40, which corresponds to the functions of the engagement device control unit 98c and the torque-up control unit 98d, the engagement control of the brake B2 and the clutch C2 is started, and the release state of the brake B1 and the clutches C1, C3, and C4 is maintained. In addition, in S40, the torque-up control is executed during the packing period of the brake B2 while the engagement control of the brake B2 is being executed. If the determination in S30 is negative, S30 is executed again.

[0070] After execution of S40, in S50 corresponding to the function of the range determination unit 98a, it is determined whether the automatic transmission 28 has been switched from the non-driving range to the D range. If the determination in S50 is positive, in S60 corresponding to the function of the shift control unit 96, engagement control of the clutch C1 is executed so as to form the first gear shift stage "1st" of the D range. If the determination in S50 is negative, in S70 corresponding to the function of the range determination unit 98a, it is determined whether the automatic transmission 28 has been switched from the non-driving range to the R range. If the determination in S70 is positive, in S80 corresponding to the function of the shift control unit 96, engagement control of the clutch C3 is executed so as to form the R range. If the determination in S70 is negative, S50 is executed again.

[0071] If the determination in S20 is negative, in S90 corresponding to the function of the range determination unit 98a, it is determined whether the automatic transmission 28 has been switched from the non-driving range to the D range. If the determination in S90 is positive, in S100 corresponding to the function of the shift control unit 96, engagement control of the brake B2 and the clutches C1 and C2 is executed so as to form the first gear shift stage "1st" of the D range. If the determination in S90 is negative, in S110 corresponding to the function of the range determination unit 98a, it is determined whether the automatic transmission 28 has been switched from the non-driving range to the R range. If the determination in S110 is positive, in S120 corresponding to the function of the shift control unit 96, engagement control of the brake B2 and the clutches C2 and C3 is executed so as to form the R range. If the determination in S110 is negative, S90 is executed again.

[0072] After execution of S60, S80, S100, S120, and S130, the process returns.

[0073] FIG. 5 is an example of a time chart when the flowchart of FIG. 4 is executed. In FIG. 5, the oil temperature THoil is in a temperature range that is equal to or lower than the first judgment temperature THoil_jdg1 and equal to or higher than the second judgment temperature THoil_jdg2. In FIG. 5, the horizontal axis is time t [ms]. The B2 command pressure Pb2 [Pa] is a command pressure of the hydraulic oil OIL supplied to the hydraulic actuator that controls the engagement / disengagement state of the brake B2, and the C2 command pressure Pc2 [Pa] is a command pressure of the hydraulic oil OIL supplied to the hydraulic actuator that controls the engagement / disengagement state of the clutch C2. The solid and dashed lines in the torque increase request amount Teup indicate the cases where the automatic transmission 28 is switched from the non-driving range to the D range at time t5 and time t6, respectively.

[0074] At time t0, the ignition switch 88 is operated by the driver, and the engine start signal IG is switched from the OFF state to the ON state. This causes the starter motor 44 to rotate and start the operation of the engine 12. After the engine 12 is in an operating state, the rotational drive of the starter motor 44 is stopped, the rotational drive of the EOP 54 is started, and control is started to change the clutch K0 from a released state to a half-engaged state to a fully engaged state.

[0075] At time t1 (>t0), the clutch K0 is fully engaged, and the engine rotation speed Ne and the MG rotation speed Nmg become the same. Time t1 is the time when the ready-off state is switched to the ready-on state, and is the time when the engine 12 is in operation in the engine driving mode, the clutch K0 is engaged, and the engine torque Te is transmitted to the electric motor connecting shaft 22. The turbine rotation speed Nt becomes the same as the engine rotation speed Ne slightly after the MG rotation speed Nmg.

[0076] During the period from time t1 to time t2 (>t1), the B2 command pressure Pb2 is set to the rapid filling pressure, and during the period from time t2 to time t9 (>t2), the B2 command pressure Pb2 is set to the constant standby pressure. The period from time t1 to time t9 is the packing period of the brake B2. After time t1, the C2 command pressure Pc2 is set to the engagement pressure that engages the clutch C2.

[0077] During the period from time t0 to time t3 (>t2), the engine torque Te is set to the idling torque Teidle, and the torque increase request amount Teup is zero. When the engagement control of the brake B2 is executed, the brake B2 drags the hydraulic oil OIL, and the drag torque of the brake B2 (= the load torque for the engine 12) increases. In response to the increase in the load torque, the torque increase request amount Teup in the torque-up control is increased. The torque increase request amount Teup is increased at a constant increase rate Csp1 [Nm / ms] during the period from time t3 to time t4 (>t3), and is set to a constant value after time t4. The delay time tdly is the period from time t1 to time t3, and is the delay time from when the engagement control of the brake B2 is started after the ready-on state is entered until the drag torque of the brake B2 starts to increase. The delay time tdly is determined experimentally or by design based on the oil temperature THoil, the quick fill pressure and its period, and the constant pressure standby pressure and its period. The torque-up control is started when the drag torque of the brake B2 starts to increase after the delay time tdly has elapsed. The torque increase request amount Teup is increased according to the increase in the drag torque after the delay time tdly has elapsed.

[0078] After time t4, when the automatic transmission 28 is switched from the non-driving range to the D range, the engine torque Te is increased accordingly to drive the vehicle 10. Therefore, the torque increase request amount Teup in the torque-up control may be zero.

[0079] For example, when the automatic transmission 28 is switched from a non-driving range (e.g., P range) to a D range at time t5 (>t4), the torque increase request amount Teup is gradually decreased at a constant decrease rate Csp2 [Nm / ms] in the period from time t5 to time t7 (>t5). At time t7, the torque increase request amount Teup is set to zero. For example, when the automatic transmission 28 is switched from a non-driving range (e.g., P range) to a D range at time t6 (>t4), the torque increase request amount Teup is gradually decreased at a constant decrease rate Csp3 [Nm / ms] in the period from time t6 to time t8 (>t6). At time t8, the torque increase request amount Teup is set to zero. The execution period texe [ms] shown in FIG. 5 is a period during which the torque-up control is executed during the execution of the engagement control of the brake B2 before the automatic transmission 28 is switched from the non-driving range to the D range.

[0080] At time t9 (>t7, t8), the B2 command pressure Pb2 is gradually increased, and the brake B2 is gradually brought from the half-engaged state to the fully-engaged state. Although not shown, after time t9, the command pressure (=C1 command pressure) of the hydraulic oil OIL supplied to the hydraulic actuator that controls the engagement and disengagement state of the clutch C1 is set to an engagement pressure that brings the clutch C1 into the engaged state.

[0081] According to this embodiment, (a) when engine torque Te is transmitted to the AT input shaft 26 and the oil temperature THoil is below the first judgment temperature THoil_jdg1 and the oil temperature THoil is above the second judgment temperature THoil_jdg2, an engagement device control unit 98c is provided that starts engagement control of brake B2 and clutch C2 before switching from the non-driving range to the driving range and executes control to maintain brake B1 and clutches C1, C3, C4 in a released state, and (b) a torque-up control unit 98d is provided that executes torque-up control to increase engine torque Te compared to before the start of engagement control of brake B2 during the packing period while engagement control of brake B2 is being executed. When the oil temperature THoil is below the first judgment temperature THoil_jdg1 and above the second judgment temperature THoil_jdg2, engagement control of brake B2 is initiated before switching from the non-driving range to the driving range, thereby ensuring responsiveness to shift operations after engine start, and torque-up control is executed to increase engine torque Te, thereby suppressing stalls caused by rotational fluctuations within the automatic transmission 28.

[0082] According to this embodiment, when the non-driving range is switched to the D range during the execution of the torque-boost control, the torque-boost control unit 98d gradually reduces the torque increase request amount Teup. When the range is switched to the D range, the engine torque Te is increased accordingly, so the torque increase request amount Teup for suppressing the occurrence of an engine stall may be zero. By gradually reducing the torque increase request amount Teup, the discomfort felt by the driver due to the reduction in the drive torque Tr [Nm] transmitted to the drive wheels 14 after switching to the D range is reduced, compared to the case where the torque increase request amount Teup is instantly reduced to zero.

[0083] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0084] In the above embodiment, the torque-up control is executed during the packing period during the execution of the engagement control of the brake B2, but for example, when the automatic transmission 28 is switched from the non-driving range to the D range after time t9 shown in the time chart of Fig. 5, the torque-up control may be executed during the period from time t9 to the switching to the D range, that is, during the half-engaged state during the execution of the engagement control of the brake B2. By executing the torque-up control during the period during which the brake B2 is half-engaged after time t9, the occurrence of an engine stall due to a rotation fluctuation in the automatic transmission 28 during this period is suppressed.

[0085] In the above-described embodiment, the relationship between the torque increase requirement Teup and the oil temperature THoil was not specifically mentioned, but preferably the torque increase requirement Teup is set to an amount that is determined in advance experimentally or by design according to the oil temperature THoil. The rotation fluctuation (amount of fluctuation per time) in the automatic transmission 28 changes according to the oil temperature THoil. By setting the torque increase requirement Teup according to the oil temperature THoil, it becomes possible to reduce the torque increase requirement Teup for suppressing the occurrence of an engine stall due to the rotation fluctuation in the automatic transmission 28, compared to a case where the torque increase requirement Teup is not set according to the oil temperature THoil. This suppresses an increase in fuel consumption.

[0086] In the time chart of FIG. 5 in the embodiment described above, the engine speed Ne does not change due to the execution of the torque-boost control. However, for example, when the engine speed Ne becomes equal to or higher than a judgment speed Ne_jdg [rpm] that is higher than the idling speed by a predetermined value due to the execution of the torque-boost control, the torque-boost control unit 98d may gradually reduce the torque increase request amount Teup. The judgment speed Ne_jdg is a judgment value of the engine speed Ne that is determined in advance experimentally or by design in order to judge whether the engine 12 has revved up. When the engine 12 revs up due to the execution of the torque-boost control and the engine speed Ne becomes equal to or higher than the judgment speed Ne_jdg, the torque increase request amount Teup is gradually reduced, thereby eliminating the revving up of the engine 12. The judgment speed Ne_jdg corresponds to the "predetermined speed" in the present invention.

[0087] In the above embodiment, when the ignition switch 88 is in the on state, before the automatic transmission 28 is switched from the non-driving range to the D range, the engagement device control unit 98c executes the engagement control and the torque-up control unit 98d executes the torque-up control. For example, even if the engagement control is started and the torque-up control is executed before the automatic transmission 28 is switched from the non-driving range to the D range with the ignition switch 88 in the on state, if the ignition switch 88 is in the off state before the execution of these controls is completed, the engagement device control unit 98c does not execute the engagement control and the torque-up control unit 98d does not execute the torque-up control. When the ignition switch 88 is in the off state, the control to stop the engine 12 is executed, so there is no need to suppress the occurrence of engine stall. Therefore, when the ignition switch 88 is in the off state, if the engagement control by the engagement device control unit 98c is not executed and the torque-up control by the torque-up control unit 98d is not executed, the engine 12 is stopped more quickly than in the other cases.

[0088] In the above embodiment, the engagement control of the brake B2 and the clutch C2 is started before switching from the non-driving range to the D range. However, for example, the engagement control of the brake B2 is started before switching from the non-driving range to the D range, but the engagement control of the clutch C2 may not be started. In this embodiment, the brake B2 corresponds to the "predetermined engagement device" in the present invention. In this embodiment, the AT input shaft rotation speed Nin fluctuates via the planetary gear devices 66, 68 due to drag caused by the brake B2. Therefore, when the oil temperature THoil is within a predetermined low temperature range, the torque-up control is executed to suppress the occurrence of an engine stall.

[0089] 5 in the above embodiment, the non-driving range is switched to the D range, but the same applies to the case where the non-driving range is switched to the R range. However, after time t9, instead of the C1 command pressure, the command pressure of the hydraulic oil OIL (=C3 command pressure) supplied to the hydraulic actuator that controls the engagement and disengagement state of the clutch C3 becomes the engagement pressure that engages the clutch C3.

[0090] In the above-described embodiment, the vehicle 10 is configured so that the engine 12 is started by the rotational drive of the starter motor 44. However, the present invention is also applicable to a configuration in which the vehicle 10 does not include the starter motor 44, and the engine 12 is started by the rotational drive of the electric motor MG and the engagement of the clutch K0. The present invention is also applicable to a configuration in which the vehicle 10 does not include the clutch K0 and the electric motor MG.

[0091] In the above-described embodiment, the vehicle 10 is provided with the torque converter 24, which is a fluid-type power transmission device, in the power transmission path PT between the driving power source PG for driving and the automatic transmission 28, but for example, another fluid-type power transmission device, such as a fluid coupling that does not have a torque amplifying effect, may be provided instead of the torque converter 24. Also, the vehicle 10 does not necessarily need to be provided with a fluid-type power transmission device, and it may be replaced with, for example, a clutch for starting.

[0092] It should be noted that the above is merely an embodiment of the present invention, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention. [Explanation of symbols]

[0093] 10: Vehicle 12: Engine 14: Drive wheel 26: AT input shaft (automatic transmission input shaft) 28: Automatic transmission 88: Ignition switch (start switch) 90: Electronic control device (control device) 98c: Engagement device control section 98d: Torque-up control section B1: Brake (plurality of second engagement devices) B2: Brake (first engagement device, specified engagement device) C1: Clutch (a plurality of second engagement devices, at least a portion of the second engagement devices) C2: Clutch (first engagement device) C3: Clutch (a plurality of second engagement devices, at least a portion of the second engagement devices) C4: Clutch (plurality of second engagement devices) CB: Gear shift engagement device (multiple friction engagement devices) Ne: Engine speed (engine rotation speed) Ne_jdg: Judgment rotation speed (predetermined rotation speed) OIL: Hydraulic oil PT: Power transmission path Te: Engine torque (engine output torque) Teup: Torque increase demand (increase in engine output torque) THoil: Oil temperature

Claims

1. A control device for a vehicle, comprising: an engine; and a planetary gear type automatic transmission provided in a power transmission path between the engine and drive wheels and having a plurality of hydraulic friction engagement devices, the plurality of friction engagement devices including a first engagement device and a plurality of second engagement devices, the automatic transmission being placed in a neutral state when the second engagement device is placed in a disengaged state, and when a gear stage in a driving range is formed, at least some of the second engagement devices and the first engagement device are all placed in an engaged state, an engagement device control unit that, when an output torque of the engine is transmitted to an input shaft of the automatic transmission and an oil temperature of hydraulic oil that controls an actuation state of the first engagement device is within a predetermined low temperature range, initiates engagement control for switching a predetermined engagement device, which varies the rotational speed of the engine when switched to an engaged state, among the first engagement devices before switching from a non-traveling range to the traveling range, to an engaged state and executes control to maintain the second engagement device in a released state; a torque-up control unit that executes a torque-up control to increase an output torque of the engine during execution of the engagement control compared to a torque before the start of the engagement control. A vehicle control device comprising:

2. The torque-up control unit executes the torque-up control during a period in which the predetermined engagement device is in a semi-engaged state during execution of the engagement control.

2. The vehicle control device according to claim 1.

3. The torque-up control unit executes the torque-up control during a packing period of the predetermined engagement device during execution of the engagement control.

3. The vehicle control device according to claim 1 or 2.

4. The amount of increase in the output torque of the engine in the torque-boost control is set in accordance with the oil temperature.

4. The vehicle control device according to claim 1,

5. When the non-driving range is switched to the driving range during execution of the torque-boost control, the torque-boost control unit gradually reduces the increase in the output torque of the engine in the torque-boost control.

5. The vehicle control device according to claim 1,

6. When the rotation speed of the engine becomes equal to or higher than a predetermined rotation speed as a result of the execution of the torque-boost control, the torque-boost control unit gradually reduces the increase in the output torque of the engine in the torque-boost control.

6. The vehicle control device according to claim 1,

7. When a start switch for starting the engine is in an on state, the engagement device control section executes the engagement control and the torque-up control section executes the torque-up control, and when the start switch is in an off state, the engagement device control section does not execute the engagement control and the torque-up control section does not execute the torque-up control.

7. The vehicle control device according to claim 1,

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