JP7505974B2 - Vehicle control device - Google Patents

Description

The present invention relates to a control device for a vehicle equipped with an engine, an electric motor, and a clutch capable of disconnecting the engine from the electric motor.

A vehicle control device is well known that includes an engine, an electric motor connected to a power transmission path between the engine and driving wheels so as to be capable of transmitting power, a clutch that is provided between the engine and the electric motor in the power transmission path and whose control state is switched by controlling a hydraulic clutch actuator, and a hydraulic control circuit that supplies regulated hydraulic pressure to the clutch actuator. For example, a vehicle control device described in Patent Document 1 is such a device. Patent Document 1 discloses that when starting the engine, the clutch is engaged while slipping to increase the rotation speed of the engine, and a compensation torque is output from the electric motor so as to cancel the deceleration torque generated by the engagement of the clutch, timing learning is first performed to correct the difference in the generation timing between the clutch transmission torque and the compensation torque, and after the difference in the generation timing has converged, magnitude learning is performed to correct the difference in the magnitude between the clutch transmission torque and the compensation torque, and after the difference in the magnitude has converged, first fill time learning is performed to temporarily increase the hydraulic command value at the start of clutch engagement to correct the first fill time to promote clutch packing.

JP 2018-79876 A

However, since clutch engagement control is performed so as to generate clutch transmission torque after first fill, a change in the first fill time affects hydraulic control after first fill. For example, if first fill time learning is performed after the occurrence timing has converged due to timing learning, the occurrence timing deviation may increase again, and the occurrence timing deviation may not be able to converge. As a result, there is a risk that the progress of learning control related to clutch engagement at engine start may be delayed.

The present invention was made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can quickly progress learning control related to clutch engagement at engine start.

The gist of the first invention is a control device for a vehicle including: (a) an engine; an electric motor connected to a power transmission path between the engine and drive wheels so as to be capable of transmitting power; a clutch whose control state is switched by controlling a hydraulic clutch actuator provided between the engine and the electric motor in the power transmission path; and a hydraulic control circuit that supplies regulated hydraulic pressure to the clutch actuator, (b) a start control unit that controls the electric motor so as to increase the output torque of the electric motor by a required cranking torque, which is a torque required for cranking the engine, when the engine is started, and controls the engine so that the engine starts operating; and (c) a hydraulic pressure command value for cranking that adjusts the hydraulic pressure to the clutch actuator so that the clutch transmits the required cranking torque is output to the hydraulic control circuit as a hydraulic pressure command value for supplying the hydraulic pressure during an engagement transition in which the control state of the clutch is switched from a released state to an engaged state, and prior to the output of the hydraulic pressure command value for cranking, a hydraulic pressure command value for adjusting the hydraulic pressure to the clutch actuator is output to the hydraulic control circuit so as to adjust the hydraulic pressure to the clutch actuator so that the clutch transmits the required cranking torque, and a hydraulic pressure command value for adjusting the hydraulic pressure to the clutch actuator so that the clutch transmits the required cranking torque, and a hydraulic pressure command value for adjusting the hydraulic pressure to the clutch actuator so that the clutch transmits the required cranking torque, when the clutch is started, is output as a hydraulic pressure command value. (d) a learning control unit that performs a plurality of types of learning controls to correct a relationship that represents a correlation between the hydraulic pressure during the engagement transition of the clutch and the hydraulic pressure command value, (e) the learning control unit gives highest priority to quick fill time learning among the plurality of types of learning controls, which corrects a quick fill time for which the quick fill hydraulic pressure command value is output, and (f) after it is determined that the quick fill time, which is a learned value in the quick fill time learning, has converged, The object of the present invention is to determine whether or not a learning value has converged in at least one of the multiple types of learning controls: packing completion hydraulic pressure learning, which corrects the hydraulic pressure to bring the clutch into the packing completion state; rising time point learning, which corrects the difference between the transmission torque rising time point at which the transmission torque of the clutch rises toward the required cranking torque and the electric motor torque rising time point at which the electric motor starts to increase the required cranking torque; and transmission torque learning, which corrects the difference between the required cranking torque and the transmission torque of the clutch caused by the cranking hydraulic pressure command value.

The second invention is a vehicle control device according to the first invention, in which the learning control unit performs the rising edge learning based on a numerical value that indicates the degree of a phenomenon that occurs due to the learning value in the learning control not being converged during the period from when the clutch is in the packing completion state until the difference between the estimated value of the transmission torque calculated using a predetermined function that reflects the response characteristics of the transmission torque of the clutch that is increased toward the required cranking torque and the required cranking torque becomes equal to or less than a predetermined value at which it can be determined that the estimated value of the transmission torque is approaching the required cranking torque.

According to the first invention, among the multiple types of learning controls, the rapid fill time learning is executed with the highest priority, and after it is determined that the rapid fill time, which is the learning value in the rapid fill time learning, has converged, it is determined whether or not the learning value in at least one of the multiple types of learning controls, the packing completion hydraulic pressure learning, the rising point learning, and the transmission torque learning, has converged. Therefore, the rapid fill time is quickly converged by the rapid fill time learning, and the learning value in the learning control other than the rapid fill time learning is appropriately converged in a state in which it is less susceptible to the influence of the correction of the rapid fill time. Therefore, the learning control related to the engagement of the clutch at the time of engine start can be quickly progressed.

In addition, according to the second invention, the rising point learning is performed based on a numerical value that indicates the degree of the phenomenon caused by the learning value in the learning control not converging during the period from when the clutch is in the packing completion state until the difference between the estimated value of the clutch transmission torque and the required cranking torque becomes equal to or less than a predetermined value. Therefore, the rising point learning can be performed appropriately while suppressing the influence of the deviation between the required cranking torque and the clutch transmission torque caused by the cranking hydraulic pressure command value.

1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and a control system for various controls in the vehicle. FIG. 2 is a partial cross-sectional view showing an example of a K0 clutch. 11 is a table illustrating an example of each phase in the K0 control phase definition. FIG. 4 is a diagram showing an example of a time chart when engine start control is executed; 1 is a flowchart illustrating the main control operations of an electronic control device, and is a flowchart illustrating the control operations for quickly progressing K0 learning control related to engagement of the K0 clutch at engine start.

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

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

The engine 12 is a known internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 has an engine control device 50, which includes a throttle actuator, a fuel injection device, an ignition device, and the like, provided on the vehicle 10, controlled by an electronic control device 90 (described later), thereby controlling the engine torque Te, which is the output torque of the engine 12.

The electric motor MG is a rotating electric machine that functions as a motor to generate mechanical power from electric power and as a generator to generate electric power from mechanical power, and is a so-called motor generator. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The electric motor MG controls the MG torque Tm, which is the output torque of the electric motor MG, by controlling the inverter 52 by an electronic control device 90 described later. For example, when the rotation direction of the electric motor MG is the same as the rotation direction when the engine 12 is operating, the MG torque Tm is a power torque in the positive torque on the acceleration side, and a regenerative torque in the negative torque on the deceleration side. Specifically, the electric motor MG generates power for running using electric power supplied from the battery 54 via the inverter 52 instead of or in addition to the engine 12. The electric motor MG also generates power using the power of the engine 12 and the driven force input from the drive wheels 14 side. The electric power generated by the electric motor MG is stored in the battery 54 via the inverter 52. The battery 54 is an electric storage device that supplies electric power to the electric motor MG. When no particular distinction is made, the electric power is also synonymous with electrical energy. When no particular distinction is made, the motive power is also synonymous with torque and force.

The power transmission device 16 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, and the like, in a case 18, which is a non-rotating member attached to the vehicle body. The K0 clutch 20 is a clutch provided between the engine 12 and the electric motor MG in the power transmission path between the engine 12 and the drive wheels 14. The torque converter 22 is connected to the engine 12 via the K0 clutch 20. The automatic transmission 24 is connected to the torque converter 22 and is interposed in the power transmission path between the torque converter 22 and the drive wheels 14. The torque converter 22 and the automatic transmission 24 each constitute a part of the power transmission path between the engine 12 and the drive wheels 14. The power transmission device 16 also includes a propeller shaft 28 connected to a transmission output shaft 26, which is an output rotating member of the automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, a pair of drive shafts 32 connected to the differential gear 30, and the like. The power transmission device 16 also includes an engine connecting shaft 34 that connects the engine 12 and the K0 clutch 20, and an electric motor connecting shaft 36 that connects the K0 clutch 20 and the torque converter 22.

The electric motor MG is connected to the electric motor connecting shaft 36 in the case 18 so as to be capable of transmitting power. The electric motor MG is connected to the power transmission path between the engine 12 and the drive wheels 14, in particular to the power transmission path between the K0 clutch 20 and the torque converter 22 so as to be capable of transmitting power. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 so as to be capable of transmitting power without passing through the K0 clutch 20. In other words, the torque converter 22 and the automatic transmission 24 each constitute a part of the power transmission path between the electric motor MG and the drive wheels 14. The torque converter 22 and the automatic transmission 24 each transmit the driving force from the driving force sources of the engine 12 and the electric motor MG to the drive wheels 14.

The torque converter 22 includes a pump wheel 22a connected to the motor connecting shaft 36, and a turbine wheel 22b connected to the transmission input shaft 38, which is an input rotating member of the automatic transmission 24. The pump wheel 22a is connected to the engine 12 via the K0 clutch 20, and is also directly connected to the electric motor MG. The pump wheel 22a is an input member of the torque converter 22, and the turbine wheel 22b is an output member of the torque converter 22. The motor connecting shaft 36 is also an input rotating member of the torque converter 22. The transmission input shaft 38 is also an output rotating member of the torque converter 22, which is integrally formed with the turbine shaft that is rotated by the turbine wheel 22b. The torque converter 22 is a fluid-type transmission device that transmits driving force from each of the driving force sources (engine 12, electric motor MG) to the transmission input shaft 38 via a fluid. The torque converter 22 includes an LU clutch 40 that connects the pump wheel 22a and the turbine wheel 22b. The LU clutch 40 is a direct-coupled clutch that connects the input and output rotating members of the torque converter 22, i.e., a well-known lock-up clutch.

The LU clutch 40 switches between operating and control states by changing the LU torque Tlu, which is the torque capacity of the LU clutch 40, using the LU oil pressure PRlu, which is a regulated oil pressure supplied from the oil pressure control circuit 56 provided in the vehicle 10. The control states of the LU clutch 40 include a fully released state in which the LU clutch 40 is released, a slip state in which the LU clutch 40 is engaged with slipping, and a fully engaged state in which the LU clutch 40 is engaged. When the LU clutch 40 is in the fully released state, the torque converter 22 is in a torque converter state in which a torque amplification effect is obtained. When the LU clutch 40 is in the fully engaged state, the torque converter 22 is in a lock-up state in which the pump impeller 22a and the turbine impeller 22b are rotated together.

The automatic transmission 24 is a known planetary gear type automatic transmission that includes, for example, one or more planetary gear sets (not shown) and multiple engagement devices CB. The engagement devices CB are hydraulic friction engagement devices that are composed of, for example, multi-plate or single-plate clutches or brakes pressed by a hydraulic actuator, or band brakes tightened by a hydraulic actuator. The engagement devices CB have their respective torque capacities, or CB torques Tcb, changed by the CB hydraulic pressure PRcb, which is a pressure-regulated hydraulic pressure supplied from the hydraulic control circuit 56, thereby switching the control state, such as the engaged state or the released state.

The automatic transmission 24 is a stepped transmission in which one of a plurality of gear stages (also called gear stages) with different speed ratios (also called gear ratios) γat (=AT input rotation speed Ni/AT output rotation speed No) is formed by engaging one of the engagement devices CB. The automatic transmission 24 selectively forms a plurality of gear stages, in other words, the gear stages formed according to the driver's (=operator's) accelerator operation and the vehicle speed V, etc., by the electronic control device 90 described later. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38 and is the input rotation speed of the automatic transmission 24. The AT input rotation speed Ni is also the rotation speed of the output rotating member of the torque converter 22, and is the same value as the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22. The AT input rotation speed Ni can be expressed as the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26, and is the output rotation speed of the automatic transmission 24.

The K0 clutch 20 is a wet or dry friction engagement device, for example, composed of a multi-plate or single-plate clutch pressed by a hydraulic clutch actuator 120, which will be described later. The K0 clutch 20 has its control state switched between an engaged state, a released state, etc., by the clutch actuator 120 being controlled by an electronic control device 90, which will be described later.

Figure 2 is a partial cross-sectional view showing an example of the K0 clutch 20. In Figure 2, the K0 clutch 20 includes a clutch drum 100, a clutch hub 102, a separate plate 104, a friction plate 106, a piston 108, a return spring 110, a spring bearing plate 112, and a snap ring 114. The clutch drum 100 and the clutch hub 102 are provided on the same axis CS. In Figure 2, the radial outer periphery of the K0 clutch 20 in the upper half of the axis CS is shown. The axis CS is the axis of the engine connecting shaft 34, the electric motor connecting shaft 36, etc. The clutch drum 100 is connected to, for example, the engine connecting shaft 34 and is rotated integrally with the engine connecting shaft 34. The clutch hub 102 is connected to, for example, the electric motor connecting shaft 36 and is rotated integrally with the electric motor connecting shaft 36. The separate plates 104 are fitted with a plurality of substantially annular plate-shaped outer peripheries on the inner periphery of the cylinder portion 100a of the clutch drum 100 so as not to rotate relative to the clutch hub 102, i.e., spline-fitted. The friction plates 106 are interposed between the plurality of separate plates 104, and are fitted with a plurality of substantially annular plate-shaped inner peripheries on the outer periphery of the clutch hub 102 so as not to rotate relative to the clutch hub 102, i.e., spline-fitted. The piston 108 is provided with a pressing portion 108a on its outer periphery, which extends toward the separate plates 104 and the friction plates 106. The return spring 110 is interposed between the piston 108 and a spring receiving plate 112, and biases a part of the piston 108 so as to abut against the bottom plate portion 100b of the clutch drum 100. In other words, the return spring 110 functions as a spring element that biases the piston 108 so as to bring the separate plates 104 and the friction plates 106 into a non-engagement state. The snap ring 114 is fixed to the cylindrical portion 100a of the clutch drum 100 at a position where the separate plate 104 and the friction plate 106 are sandwiched between the pressing portion 108a of the piston 108 and the snap ring 114. In the K0 clutch 20, an oil chamber 116 is formed between the piston 108 and the bottom plate portion 100b of the clutch drum 100. In the clutch drum 100, an oil passage 118 leading to the oil chamber 116 is formed. In the K0 clutch 20, the clutch drum 100, the piston 108, the return spring 110, the spring receiving plate 112, the oil chamber 116, etc. form a clutch actuator 120 as a hydraulic actuator.

The hydraulic control circuit 56 supplies the adjusted hydraulic pressure, K0 hydraulic pressure PRk0, to the clutch actuator 120. In the K0 clutch 20, when the K0 hydraulic pressure PRk0 is supplied from the hydraulic control circuit 56 to the oil chamber 116 through the oil passage 118, the piston 108 moves toward the separate plate 104 and the friction plate 106 against the biasing force of the return spring 110 due to the K0 hydraulic pressure PRk0, and the pressing portion 108a of the piston 108 presses the separate plate 104 and the friction plate 106. When the separate plate 104 and the friction plate 106 are pressed, the K0 clutch 20 is switched to an engaged state. The control state of the K0 clutch 20 is switched by changing the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, due to the K0 hydraulic pressure PRk0. In addition, the torque capacity of the engagement devices such as LU torque Tlu, CB torque Tcb, and K0 torque Tk0 corresponds to the maximum torque that the engagement device can transmit, i.e., the maximum transmission torque, and in the narrow sense, is different from the transmission torque of the engagement device, which corresponds to the torque that the engagement device actually transmits. However, in this embodiment, unless otherwise specified, the transmission torque of the engagement device also represents the maximum torque that the engagement device can transmit. For example, K0 torque Tk0 is the same as the transmission torque of the K0 clutch 20.

The K0 torque Tk0 is determined by, for example, the friction coefficient of the friction material of the friction plate 106 and the K0 oil pressure PRk0. In the K0 clutch 20, when the oil chamber 116 is filled with hydraulic oil OIL and the pressure of the piston 108 (=PRk0 x piston pressure area) counteracts the biasing force of the return spring 110 to close the clearance between the separate plate 104 and the friction plate 106, that is, when the pack clearance of the K0 clutch 20 is closed, so-called packing is completed. In this embodiment, the state in which the pack clearance of the K0 clutch 20 is closed is referred to as the packing completion state. In the K0 clutch 20, the K0 torque Tk0 is generated by further increasing the K0 oil pressure PRk0 from the packing completion state. In other words, the packing completion state of the K0 clutch 20 is the state in which the K0 clutch 20 begins to have torque capacity, i.e., the K0 torque Tk0 begins to be generated, if the K0 oil pressure PRk0 is increased from the packing completion state. The K0 oil pressure PRk0 for packing the K0 clutch 20 is the K0 oil pressure PRk0 for bringing the piston 108 to the stroke end and for bringing the state in which the K0 torque Tk0 is not being generated.

Returning to FIG. 1, when the K0 clutch 20 is engaged, the pump impeller 22a and the engine 12 are rotated together via the engine connecting shaft 34. That is, when the K0 clutch 20 is engaged, it connects the engine 12 and the drive wheels 14 so that power can be transmitted. On the other hand, when the K0 clutch 20 is released, the power transmission between the engine 12 and the pump impeller 22a is interrupted. That is, when the K0 clutch 20 is released, it disconnects the engine 12 and the drive wheels 14. Since the electric motor MG is connected to the pump impeller 22a, the K0 clutch 20 is provided in the power transmission path between the engine 12 and the electric motor MG and functions as a clutch that disconnects the power transmission path, that is, a clutch that disconnects the engine 12 from the electric motor MG. In other words, the K0 clutch 20 is a disconnecting clutch that connects the engine 12 and the electric motor MG when engaged, and disconnects the connection between the engine 12 and the electric motor MG when released.

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 34 to the drive wheels 14 via the K0 clutch 20, the electric motor connecting shaft 36, the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. In addition, the power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the drive wheels 14 via the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc., regardless of the control state of the K0 clutch 20.

The vehicle 10 is equipped with a MOP 58, which is a mechanical oil pump, an EOP 60, which is an electric oil pump, a pump motor 62, and the like. The MOP 58 is connected to the pump impeller 22a, and is rotated and driven by a driving force source (engine 12, electric motor MG) to discharge hydraulic oil OIL used in the power transmission device 16. The pump motor 62 is a motor dedicated to the EOP 60 for rotating and driving the EOP 60. The EOP 60 is rotated and driven by the pump motor 62 to discharge hydraulic oil OIL. The hydraulic oil OIL discharged by the MOP 58 and EOP 60 is supplied to the hydraulic control circuit 56. The hydraulic control circuit 56 supplies the CB hydraulic pressure PRcb, the K0 hydraulic pressure PRk0, the LU hydraulic pressure PRlu, and the like, which are adjusted based on the hydraulic oil OIL discharged by the MOP 58 and/or the EOP 60.

The vehicle 10 further includes an electronic control device 90 that includes a control device for the vehicle 10 related to starting control of the engine 12, etc. 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 receives various signals based on detection values from various sensors provided in the vehicle 10 (e.g., engine rotation speed sensor 70, turbine rotation speed sensor 72, output rotation speed sensor 74, MG rotation speed sensor 76, accelerator opening sensor 78, throttle valve opening sensor 80, brake switch 82, battery sensor 84, oil temperature sensor 86, etc.) (e.g., engine rotation speed Ne, which is the rotation speed of the engine 12, turbine rotation speed Nt, which is the same value as AT input rotation speed Ni, AT output rotation speed No corresponding to vehicle speed V, electric motor M The following signals are supplied: MG rotation speed Nm, which is the rotation speed of G; accelerator opening θacc, which is the amount of accelerator operation by the driver that indicates the magnitude of the driver's acceleration operation; throttle valve opening θth, which is the opening of the electronic throttle valve; brake-on signal Bon, which is a signal indicating that the brake pedal for operating the wheel brakes is being operated by the driver; battery temperature THbat, battery charge/discharge current Ibat, battery voltage Vbat of battery 54; hydraulic oil temperature THoil, which is the temperature of the hydraulic oil OIL in the hydraulic control circuit 56, etc.

The electronic control device 90 outputs various command signals (e.g., engine control command signal Se for controlling the engine 12, MG control command signal Sm for controlling the electric motor MG, CB hydraulic control command signal Scb for controlling the engagement device CB, K0 hydraulic control command signal Sk0 for controlling the K0 clutch 20, LU hydraulic control command signal Slu for controlling the LU clutch 40, EOP control command signal Seop for controlling the EOP 60, etc.) to each device (e.g., engine control device 50, inverter 52, hydraulic control circuit 56, pump motor 62, etc.) provided in the vehicle 10.

The electronic control device 90 includes a hybrid control means, i.e., a hybrid control unit 92, a clutch control means, i.e., a clutch control unit 94, and a gear shift control means, i.e., a gear shift control unit 96 to realize various controls in the vehicle 10.

The hybrid control unit 92 includes a function as an engine control means, i.e., engine control unit 92a, that controls the operation of the engine 12, and a function as an electric motor control means, i.e., electric motor control unit 92b, that controls the operation of the electric motor MG via the inverter 52, and executes hybrid drive control using the engine 12 and the electric motor MG, etc., by using these control functions.

The hybrid control unit 92 calculates the driving demand amount of the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand amount map. The driving demand amount map is a relationship that is experimentally or design-wise determined and stored in advance, i.e., a predetermined relationship. The driving demand amount is, for example, the required driving torque Trdem at the driving wheels 14. In other words, the required driving torque Trdem [Nm] is the required driving power Prdem [W] at the vehicle speed V at that time. The driving demand amount can also be the required driving force Frdem [N] at the driving wheels 14, the required AT output torque at the transmission output shaft 26, etc. In calculating the driving demand amount, the AT output rotation speed No, etc. may be used instead of the vehicle speed V.

The hybrid control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the electric motor MG so as to realize the required driving power Prdem, taking into consideration the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 24, the chargeable power Win and dischargeable power Wout of the battery 54, etc. The engine control command signal Se is, for example, a command value for the engine power Pe, which is the power of the engine 12 that outputs the engine torque Te at the current engine rotation speed Ne. The MG control command signal Sm is, for example, a command value for the power consumption Wm of the electric motor MG that outputs the MG torque Tm at the current MG rotation speed Nm.

The chargeable power Win of the battery 54 is the maximum power that can be input, which specifies the limit on 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 specifies the limit on the output power of the battery 54, and indicates the output limit of the battery 54. The chargeable power Win and dischargeable power Wout of the battery 54 are calculated by the electronic control unit 90, for example, based on the battery temperature THbat and the state of charge value SOC [%] of the battery 54. The state of charge value SOC of the battery 54 is a value that indicates the state of charge of the battery 54, and is calculated by the electronic control unit 90, for example, based on the battery charge/discharge current Ibat and the battery voltage Vbat.

When the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the hybrid control unit 92 sets the driving mode to the motor driving (=EV driving) mode. In the EV driving mode, the hybrid control unit 92 performs EV driving, in which the vehicle runs using only the electric motor MG as a driving force source with the K0 clutch 20 in the released state. On the other hand, when the required drive torque Trdem cannot be satisfied without using at least the output of the engine 12, the hybrid control unit 92 sets the driving mode to the engine driving mode, i.e., hybrid driving (=HV driving) mode. In the HV driving mode, the hybrid control unit 92 performs engine driving, i.e., HV driving, in which the vehicle runs using at least the engine 12 as a driving force source with the K0 clutch 20 in the engaged state. On the other hand, even if the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the hybrid control unit 92 establishes the HV driving mode when the state of charge value SOC of the battery 54 is less than a predetermined engine start threshold value or when the engine 12, etc., needs to be warmed up. The engine start threshold is a predetermined threshold for determining that the state of charge value SOC is at a value at which it is necessary to forcibly start the engine 12 and charge the battery 54. In this way, the hybrid control unit 92 switches between the EV driving mode and the HV driving mode by automatically stopping the engine 12 during HV driving, restarting the engine 12 after the engine has stopped, or starting the engine 12 during EV driving, based on the required driving torque Trdem, etc.

The hybrid control unit 92 further includes a function as a start control means, i.e., a start control unit 92c, and a function as a stop control means, i.e., a stop control unit 92d.

The start control unit 92c determines whether or not there is a request to start the engine 12. For example, in the EV driving mode, the start control unit 92c determines whether or not there is a request to start the engine 12 based on whether or not the required drive torque Trdem has increased beyond the range that can be covered by the output of the electric motor MG alone, whether or not warming up of the engine 12, etc. is necessary, or whether or not the state of charge value SOC of the battery 54 is less than the engine start threshold. The start control unit 92c also determines whether or not the start control of the engine 12 has been completed.

The clutch control unit 94 controls the K0 clutch 20 to execute start control of the engine 12. For example, when the start control unit 92c determines that there is a request to start the engine 12, the clutch control unit 94 outputs a K0 hydraulic control command signal Sk0 to the hydraulic control circuit 56 to control the K0 clutch 20 in the released state toward the engaged state so that the K0 torque Tk0 for transmitting the torque required for cranking the engine 12, which is the torque that increases the engine rotation speed Ne, to the engine 12 side is obtained. In other words, when starting the engine 12, the clutch control unit 94 outputs a K0 hydraulic control command signal Sk0 to the hydraulic control circuit 56 to control the clutch actuator 120 to switch the control state of the K0 clutch 20 from the released state to the engaged state. In this embodiment, the torque required for cranking the engine 12 is called the required cranking torque Tcrn.

The start control unit 92c controls the engine 12 and the electric motor MG to execute start control of the engine 12. For example, when the start control unit 92c determines that there is a request to start the engine 12, it outputs an MG control command signal Sm to the inverter 52 so that the electric motor MG outputs the required cranking torque Tcrn in accordance with the switching of the K0 clutch 20 to the engaged state by the clutch control unit 94. In other words, when starting the engine 12, the start control unit 92c outputs an MG control command signal Sm to the inverter 52 so that the electric motor MG outputs the required cranking torque Tcrn, i.e., so that the MG torque Tm is increased by the required cranking torque Tcrn.

When the start control unit 92c determines that there is a request to start the engine 12, it outputs an engine control command signal Se to the engine control device 50 to start fuel supply, engine ignition, and the like, in conjunction with cranking of the engine 12 by the K0 clutch 20 and the electric motor MG. In other words, when starting the engine 12, the start control unit 92c outputs an engine control command signal Se to the engine control device 50 to control the engine 12 so that the engine 12 starts operating.

When cranking the engine 12, a cranking reaction torque Trfcr, which is a reaction torque associated with the engagement of the K0 clutch 20, is generated. During EV driving, this cranking reaction torque Trfcr causes a pulling sensation of the vehicle 10 due to the inertia during engine start, that is, a drop in the drive torque Tr. Therefore, the MG torque Tm that is increased toward the required cranking torque Tcrn when starting the engine 12 is the MG torque Tm for canceling the cranking reaction torque Trfcr, and is the MG torque Tm for compensating for the cranking reaction torque Trfcr, i.e., the MG torque Tm for K0 reaction compensation. The required cranking torque Tcrn is the K0 torque Tk0 required for cranking the engine 12, and is the MG torque Tm required for cranking the engine 12 that flows from the electric motor MG side to the engine 12 side via the K0 clutch 20. The required cranking torque Tcrn is, for example, a constant cranking torque Tcr that is determined in advance based on, for example, the specifications of the engine 12, the starting method of the engine 12, etc.

When starting the engine 12 during EV driving, the start control unit 92c causes the electric motor MG to output the MG torque Tm for the required cranking torque Tcrn in addition to the MG torque Tm for EV driving, i.e., the MG torque Tm that generates the driving torque Tr. Therefore, during EV driving, it is necessary to ensure the required cranking torque Tcrn in preparation for starting the engine 12. Therefore, the range in which the required driving torque Trdem can be satisfied only by the output of the electric motor MG is the torque range obtained by subtracting the required cranking torque Tcrn from the maximum torque that can be output by the electric motor MG. The maximum torque that can be output by the electric motor MG is the maximum MG torque Tm that can be output by the dischargeable power Wout of the battery 54.

The stop control unit 92d determines whether or not there is a request to stop the engine 12. For example, in the HV driving mode, the stop control unit 92d determines whether or not there is a request to stop the engine 12 based on whether or not the required drive torque Trdem is within a range that can be covered by the output of the electric motor MG alone, there is no need to warm up the engine 12, and the state of charge value SOC of the battery 54 is equal to or higher than the engine start threshold.

The stop control unit 92d controls the engine 12 to execute stop control of the engine 12. For example, when the stop control unit 92d determines that there is a request to stop the engine 12, it outputs an engine control command signal Se to the engine control device 50 to stop the supply of fuel to the engine 12. In other words, when the engine 12 is stopped, the stop control unit 92d outputs an engine control command signal Se to the engine control device 50 to control the engine 12 so that the engine 12 stops operating.

The clutch control unit 94 controls the K0 clutch 20 when the engine 12 is stopped. For example, when the stop control unit 92d determines that there is a request to stop the engine 12, the clutch control unit 94 outputs a K0 hydraulic control command signal Sk0 to the hydraulic control circuit 56 to control the engaged K0 clutch 20 toward a released state. In other words, when it is determined that there is a request to stop the engine 12, that is, when there is a request to stop the engine 12, the clutch control unit 94 outputs a K0 hydraulic control command signal Sk0 to the hydraulic control circuit 56 to control the clutch actuator 120 to switch the control state of the K0 clutch 20 from an engaged state to a released state.

The shift control unit 96 uses, for example, a shift map, which is a predetermined relationship, to determine whether the automatic transmission 24 should be shifted, and outputs a CB hydraulic control command signal Scb to the hydraulic control circuit 56 to execute shift control of the automatic transmission 24 as necessary. The shift map is a predetermined relationship having a shift line for determining whether the automatic transmission 24 should be shifted, on a two-dimensional coordinate system with, for example, vehicle speed V and required driving torque Trdem as variables. In the shift map, the AT output rotation speed No may be used instead of the vehicle speed V, and the required driving force Frdem, accelerator opening θacc, throttle valve opening θth, etc. may be used instead of the required driving torque Trdem.

Here, in order to accurately control the control state of the K0 clutch 20 when starting the engine 12, a K0 control phase definition Dphk0 is predefined in the electronic control unit 90. The K0 control phase definition Dphk0 defines multiple progression stages, or phases, for controlling the clutch actuator 120, which are divided according to the control state of the K0 clutch 20 that is switched during the engine 12 startup process.

Figure 3 is a chart explaining an example of each phase in the K0 control phase definition Dphk0. In Figure 3, the K0 control phase definition Dphk0 defines phases such as "K0 standby", "quick apply", "constant pressure standby when packing", "K0 cranking", "quick drain", "constant pressure standby before re-engagement", "initial rotation synchronization", "middle rotation synchronization", "final rotation synchronization", "engagement transition sweep", "full engagement transition sweep", "full engagement", "backup sweep", and "calculation stop".

The "K0 standby" phase is a phase in which control of the K0 clutch 20 is not started and the engine 12 is kept on standby during startup control of the engine 12. The "K0 standby" phase is entered if a K0 standby determination is made when starting control of the engine 12.

The "quick apply" phase is a phase in which a quick apply is performed to apply a temporarily high command value for the K0 oil pressure PRk0 in order to quickly complete packing of the K0 clutch 20, thereby improving the initial responsiveness of the K0 oil pressure PRk0. The "quick apply" phase is entered if there is no K0 standby determination when starting control of the engine 12. Alternatively, the "quick apply" phase is entered from the "K0 standby" phase if the K0 standby determination is withdrawn while waiting for control of the K0 clutch 20 to begin.

The command value of the K0 hydraulic pressure PRk0 is a hydraulic pressure command value for causing the hydraulic control circuit 56 to supply the adjusted K0 hydraulic pressure PRk0. In this embodiment, the command value of the K0 hydraulic pressure PRk0 is referred to as the K0 hydraulic pressure command value Spk0. The K0 hydraulic pressure command value Spk0 is uniquely converted into an instruction current for a solenoid driver that drives the solenoid valve for the K0 clutch 20 provided in the electronic control device 90. The solenoid valve for the K0 clutch 20 is a solenoid valve that outputs the K0 hydraulic pressure PRk0 provided in the hydraulic control circuit 56. The K0 hydraulic pressure control command signal Sk0 is an instruction current for a solenoid driver that drives the solenoid valve for the K0 clutch 20, or a drive current or drive voltage supplied by this solenoid driver. In other words, the K0 hydraulic pressure command value Spk0 is converted into the K0 hydraulic pressure control command signal Sk0 and output to the hydraulic control circuit 56. In this embodiment, for convenience, the K0 hydraulic command value Spk0 and the K0 hydraulic control command signal Sk0 are treated as the same.

The "constant pressure standby during packing" phase is a phase in which the system waits at a constant pressure to complete packing of the K0 clutch 20. The "constant pressure standby during packing" phase is entered from the "quick apply" phase when the quick apply is completed.

The "K0 cranking" phase is a phase in which the engine 12 is cranked by the K0 clutch 20. The "K0 cranking" phase is entered from the "constant pressure standby during packing" phase when packing of the K0 clutch 20 is completed.

The "quick drain" phase is a phase in which a quick drain is executed to output a temporarily low K0 oil pressure command value Spk0 so that the next phase, the "constant pressure standby before re-engagement," can quickly wait at a predetermined K0 oil pressure PRk0, for example, the pack end pressure PRk0pk, thereby improving the initial responsiveness of the K0 oil pressure PRk0. The "quick drain" phase is entered from the "K0 cranking" phase when cranking of the engine 12 is completed and a quick drain execution determination is made.

The "constant pressure standby before re-engagement" phase is a phase in which the engine waits at a predetermined K0 torque Tk0 so as not to disturb the complete combustion of the engine 12. Complete combustion of the engine 12 is a state in which the engine 12 is in a stable state of independent rotation due to the explosion of the engine 12 after the initial explosion when ignition of the engine 12 is started, for example. Not disturbing the complete combustion of the engine 12 means not interfering with the independent rotation of the engine 12. The "constant pressure standby before re-engagement" phase is transitioned from the "K0 cranking" phase when cranking of the engine 12 is completed and there is no determination to perform a quick drain. Alternatively, the "constant pressure standby before re-engagement" phase is transitioned from the "quick drain" phase when a quick drain is completed.

The "initial rotation synchronization" phase is a phase in which the K0 torque Tk0 is controlled to assist in increasing the engine speed Ne in order to quickly synchronize the engine speed Ne with the MG speed Nm. The "initial rotation synchronization" phase is transitioned from the "constant pressure standby before re-engagement" phase if the transition conditions to the "final rotation synchronization" phase and the "middle rotation synchronization" phase are not satisfied when the engine control unit 92a notifies the engine 12 of complete combustion. The engine control unit 92a outputs a complete combustion notification of the engine 12 when, for example, the elapsed time from the time when the engine speed Ne reaches a predetermined complete combustion rotation speed of the engine 12 exceeds a predetermined complete combustion notification waiting time TMeng (see FIG. 4 described later). The complete combustion notification waiting time TMeng is predetermined, for example, taking into account the exhaust gas requirements of the engine 12.

The "rotational synchronization middle" phase is a phase in which the K0 torque Tk0 is controlled so that the engine 12 has an appropriate amount of revving (=Ne-Nm). The "rotational synchronization middle" phase is transitioned from the "constant pressure wait before re-engagement" phase if the transition condition to the "rotational synchronization middle" phase is satisfied when the engine control unit 92a notifies the engine control unit 92a of complete explosion. Alternatively, the "rotational synchronization middle" phase is transitioned from the "rotational synchronization initial" phase if the transition condition to the "rotational synchronization middle" phase is satisfied during the execution of the "rotational synchronization initial" phase.

The "rotational synchronization end" phase controls the K0 torque Tk0 to synchronize the engine rotation speed Ne and the MG rotation speed Nm. The "rotational synchronization end" phase is transitioned from the "constant pressure wait before re-engagement" phase if the transition condition to the "rotational synchronization end" phase is satisfied when the engine control unit 92a notifies the engine control unit 92a of complete explosion. Alternatively, the "rotational synchronization end" phase is transitioned from the "rotational synchronization initial" phase if the transition condition to the "rotational synchronization end" phase is satisfied during the execution of the "rotational synchronization initial" phase. Alternatively, the "rotational synchronization end" phase is transitioned from the "rotational synchronization middle" phase if the transition condition to the "rotational synchronization end" phase is satisfied during the execution of the "rotational synchronization middle" phase. Alternatively, the "rotation synchronization end" phase is transitioned from the "rotation synchronization middle" phase when the automatic transmission 24 is not being controlled for shifting and a state in which it is predicted that synchronization between the engine rotation speed Ne and the MG rotation speed Nm is impossible is continuously established for a period of time equal to or longer than the forced rotation synchronization transition determination time during execution of the "rotation synchronization middle" phase.

The "engagement transition sweep" phase is a phase in which the K0 torque Tk0 is gradually increased to bring the K0 clutch 20 into an engaged state. The "engagement transition sweep" phase is transitioned from the "rotational synchronization end" phase if a rotational synchronization determination is made during execution of the "rotational synchronization end" phase.

The "full engagement transition sweep" phase is a phase in which the K0 torque Tk0 is gradually increased to bring the K0 clutch 20 into a fully engaged state. Bringing the K0 clutch 20 into a fully engaged state means, for example, increasing the K0 torque Tk0 to a state in which a safety factor is added to ensure that the K0 clutch 20 is engaged. The "full engagement transition sweep" phase is transitioned from the "engagement transition sweep" phase when the K0 engagement determination is satisfied during the execution of the "engagement transition sweep" phase. Alternatively, the "full engagement transition sweep" phase is transitioned from the "engagement transition sweep" phase when the rotational synchronization state of the K0 clutch 20 cannot be maintained during the execution of the "engagement transition sweep" phase. Alternatively, the "full engagement transition sweep" phase is transitioned from the "engagement transition sweep" phase when the elapsed time from the start of the "engagement transition sweep" phase exceeds a predetermined forced engagement transition determination time and it is determined that the absolute value of the K0 differential rotation ΔNk0 is equal to or greater than the predetermined full engagement transition sweep forced transition determination differential rotation. The K0 differential rotation speed ΔNk0 is the differential rotation speed of the K0 clutch 20 (= Nm - Ne).

The "fully engaged" phase is a phase in which the K0 clutch 20 is maintained in a fully engaged state. The "fully engaged" phase is transitioned from the "fully engaged" phase if a full engagement determination is made during execution of the "fully engaged" phase. Alternatively, the "fully engaged" phase is transitioned from the "fully engaged" phase if it is determined that the elapsed time from the start of the "fully engaged" phase is equal to or greater than a predetermined forced full engagement transition determination time and that the absolute value of the K0 differential rotation ΔNk0 is equal to or greater than a predetermined forced full engagement transition determination differential rotation.

The "fully engaged" phase can also be transitioned from the "backup sweep" phase. The "fully engaged" phase is transitioned from the "backup sweep" phase when a fully engaged determination is made during execution of the "backup sweep" phase, and a determination that the absolute value of the K0 differential rotation ΔNk0 is equal to or less than the predetermined backup-time rotation synchronization determination differential rotation is made consecutively for a predetermined number of times or more. Alternatively, the "fully engaged" phase is transitioned from the "backup sweep" phase when, during execution of the "backup sweep" phase, the elapsed time from the transition to a phase other than the "K0 standby" phase after the start of engine 12 start control is equal to or more than the predetermined engine start control timeout time, and it is determined that the absolute value of the K0 differential rotation ΔNk0 is equal to or more than the fully engaged forced transition determination differential rotation.

The "backup sweep" phase is a phase in which backup control is performed by gradually increasing the K0 torque Tk0 to engage the K0 clutch 20. The "backup sweep" phase is transitioned from the currently running phase when it is determined that the elapsed time from the start of the currently running phase exceeds a predetermined backup transition determination time for the currently running phase and that the K0 differential rotation ΔNk0 is equal to or greater than the predetermined backup transition determination differential rotation for the currently running phase, for example, during the execution of any of the "K0 cranking" phase, the "constant pressure waiting before re-engagement" phase, the "initial rotation synchronization" phase, the "middle rotation synchronization" phase, and the "final rotation synchronization" phase, in order to prevent control stacking.

The "calculation stop" phase is a phase in which calculation of the base correction pressure of the K0 oil pressure PRk0 used for the start control of the engine 12 and the required K0 torque Tk0d is stopped while the fail-safe control is being executed at the start of the engine 12. The fail-safe control is a control to switch the oil path in the hydraulic control circuit 56 so that the K0 oil pressure PRk0 capable of maintaining the fully engaged state of the K0 clutch 20 is supplied to the clutch actuator 120 without passing through the solenoid valve for the K0 clutch 20 when a failure occurs in which the regulated K0 oil pressure PRk0 is not output from the solenoid valve for the K0 clutch 20. The K0 oil pressure PRk0 capable of maintaining the fully engaged state is, for example, an original pressure such as a line pressure supplied to the solenoid valve for the K0 clutch 20. The base correction pressure is a value obtained by correcting the base pressure of the K0 oil pressure PRk0 used for the start control of the engine 12 based on the hydraulic oil temperature THoil, etc. The required K0 torque Tk0d is the K0 torque Tk0 required to crank the engine 12 and switch the K0 clutch 20 to the engaged state during start control of the engine 12.

The K0 control phase definition Dphk0 is created for the purpose of calculating the base correction pressure of the K0 oil pressure PRk0 and the required K0 torque Tk0d used, for example, in the start-up control of the engine 12. In the K0 control phase definition Dphk0, each phase is defined based on the control request state for the K0 clutch 20, such as the desire to control the K0 oil pressure PRk0 and the K0 torque Tk0. In other words, the K0 control phase definition Dphk0 is defined based on the control request to switch the control state of the K0 clutch 20.

When starting the engine 12, the clutch control unit 94 controls the clutch actuator 120 to switch the control state of the K0 clutch 20 from a released state to an engaged state based on the K0 control phase definition Dphk0.

When starting the engine 12, the start control unit 92c controls the electric motor MG and the engine 12 in accordance with the control state of the K0 clutch 20. In starting control of the engine 12, it is sufficient to control the electric motor MG so that it outputs the required cranking torque Tcrn, and also to control the engine 12 so that the engine 12 starts operating. Therefore, when starting the engine 12, the start control unit 92c controls the electric motor MG and the engine 12 based on the phases of the K0 control phase definition Dphk0 that are required for controlling the electric motor MG and the engine 12. This simplifies the control when starting the engine 12.

Figure 4 is a diagram showing an example of a time chart when the start control of the engine 12 is executed. In Figure 4, "K0 control phase" shows the transition state of each phase in the K0 control phase definition Dphk0. In addition, the total oil pressure value obtained by adding the oil pressure value obtained by converting the required K0 torque Tk0d into the K0 oil pressure PRk0 to the base correction pressure of the K0 oil pressure PRk0 is output as the K0 oil pressure command value Spk0. Time t1 indicates the time when a start request for the engine 12 is made during EV driving mode in which the vehicle is stopped in an idling state or during EV driving, and the start control of the engine 12 is started. After the start control of the engine 12 is started, the "K0 standby" phase (see time t1-t2), the "quick apply" phase (see time t2-t3), and the "constant pressure standby during packing" phase (see time t3-t4) are executed. Following the packing control of the K0 clutch 20, the "K0 cranking" phase is executed (see time t4-t5). In the embodiment of FIG. 4, in the "constant pressure standby during packing" phase, the K0 oil pressure PRk0 corresponding to the required cranking torque Tcrn required in the "K0 cranking" phase is applied. In the "constant pressure standby during packing" phase, the actual K0 oil pressure PRk0 is not increased to a value that generates the K0 torque Tk0 or more. In the "K0 cranking" phase, the actual K0 oil pressure PRk0 is increased to a value that generates the K0 torque Tk0 or more. In the "constant pressure standby during packing" phase, the K0 oil pressure PRk0 for maintaining the K0 clutch 20 in the packing completion state may be applied. In the "K0 cranking" phase, the MG torque Tm having a magnitude corresponding to the required K0 torque Tk0d, i.e., the required cranking torque Tcrn, is output from the electric motor MG. In the "K0 cranking" phase, when the engine rotation speed Ne is increased, engine ignition and the like are started and the engine 12 is first fired. In addition, when the ignition start is performed, for example, the engine 12 is initially fired at approximately the same time as the engine speed Ne starts to increase. After the initial firing of the engine 12, in order to prevent the engine 12 from being disturbed by the complete firing, the "K0 cranking" phase is followed by the "quick drain" phase (see time t5-t6) and the "constant pressure standby before re-engagement" phase (see time t6-t7), and a low K0 hydraulic pressure command value Spk0 is temporarily output. When the engine complete firing notification is output from the engine control unit 92a (see time t7), the "initial rotation synchronization" phase (see time t7-t8), the "middle rotation synchronization" phase (see time t8-t9), the "final rotation synchronization" phase (see time t9-t10), and the "engagement transition sweep ("engagement transition SW" in the figure)" phase (see time t10-t11) are executed, and the rotation synchronization control between the engine 12 and the electric motor MG is performed. Following the "engagement transition sweep" phase, a "full engagement transition sweep ("full engagement transition SW" in the figure)" phase is executed (see time t11-t12), and the K0 torque Tk0 is gradually increased to a state in which a safety factor is added to ensure engagement of the K0 clutch 20. When the K0 torque Tk0 is increased to a state in which a safety factor is added to ensure engagement of the K0 clutch 20, the "full engagement" phase is executed (see time t12-t13), and the full engagement state of the K0 clutch 20 is maintained. Time t13 indicates the time when start control of the engine 12 is completed.

Referring to the "K0 cranking" phase in FIG. 3 and FIG. 4, during the engagement transition in which the control state of the K0 clutch 20 is switched from the released state to the engaged state when the engine 12 is started, the clutch control unit 94 outputs to the hydraulic control circuit 56 the K0 hydraulic pressure command value Spk0 for cranking to adjust the K0 hydraulic pressure PRk0 to the clutch actuator 120 so that the K0 clutch 20 transmits the required cranking torque Tcrn as the K0 hydraulic pressure command value Spk0. In this embodiment, the K0 hydraulic pressure command value Spk0 for cranking is referred to as the cranking hydraulic pressure command value Spk0cr.

3 and 4, when starting the engine 12, the clutch control unit 94 outputs the K0 hydraulic pressure command value Spk0 for quick apply to the hydraulic control circuit 56 as the K0 hydraulic pressure command value Spk0 to improve the responsiveness of the K0 hydraulic pressure PRk0 to the clutch actuator 120 so that the K0 clutch 20 is quickly brought to a packing completion state, prior to outputting the cranking hydraulic pressure command value Spk0cr in the "K0 cranking" phase. The quick apply in the "quick apply" phase is also a first fill (= rapid fill) that quickly fills the oil chamber 116 of the clutch actuator 120 with hydraulic oil OIL, so the K0 hydraulic pressure command value Spk0 for quick apply is also the K0 hydraulic pressure command value Spk0 for rapid fill. In this embodiment, the K0 hydraulic pressure command value Spk0 for rapid fill is called the hydraulic pressure command value Spk0ff for rapid fill.

On the other hand, the K0 oil pressure PRk0 and the K0 torque Tk0 vary with respect to the K0 oil pressure command value Spk0 due to various factors. This can cause the MG rotation speed Nm, etc. to deviate from the target rotation speed during the engagement transition of the K0 clutch 20 during engine 12 start control. For this reason, it is desirable to perform learning control related to the engagement of the K0 clutch 20 at engine start, for example, learning control that corrects the relationship that represents the correlation between the K0 oil pressure PRk0 and the K0 oil pressure command value Spk0.

The electronic control unit 90 is further provided with a learning control means, i.e., a learning control unit 98, to realize control operations for appropriately controlling the engagement of the K0 clutch 20 when the engine 12 is started.

The learning control unit 98 performs multiple types of learning control to correct the relationship representing the correlation between the K0 oil pressure PRk0 and the K0 oil pressure command value Spk0 during the engagement transition of the K0 clutch 20 related to the start of the engine 12. The relationship representing the correlation between the K0 oil pressure PRk0 and the K0 oil pressure command value Spk0 is, for example, the correlation between the actual K0 oil pressure PRk0r, which is the actual value of the K0 oil pressure PRk0, and the K0 oil pressure command value Spk0, the correlation between the actual K0 oil pressure PRk0r and the required K0 torque Tk0d, the correlation between the actual K0 torque Tk0r, which is the actual value of the K0 torque Tk0, and the K0 oil pressure command value Spk0, and the correlation between the actual K0 torque Tk0r and the required K0 torque Tk0d. The learning control that corrects the relationship that represents the correlation between the K0 hydraulic pressure PRk0 and the K0 hydraulic pressure command value Spk0 is, for example, a learning control that corrects the variation of the actual K0 hydraulic pressure PRk0r relative to the K0 hydraulic pressure command value Spk0. In other words, the learning control that corrects the relationship that represents the correlation between the K0 hydraulic pressure PRk0 and the K0 hydraulic pressure command value Spk0 is a learning control that corrects the variation of the K0 hydraulic pressure command value Spk0 to make the actual K0 torque Tk0r the required K0 torque Tk0d. In this embodiment, this learning control is called the K0 learning control CTlrnk0. In this embodiment, unless otherwise specified, the K0 hydraulic pressure PRk0 and the K0 torque Tk0 represent the actual values. Also, the variation of the K0 hydraulic pressure PRk0 and the variation of the K0 torque Tk0 are synonymous.

The multiple types of K0 learning control CTlrnk0 include, for example, learning control that corrects the quick apply time (=QA time) TMqa, which is the execution period of the quick apply in the "quick apply" phase before the generation of the K0 torque Tk0, that is, quick fill time learning that corrects the quick fill time, which is the execution period during which the quick fill hydraulic pressure command value Spk0ff is output. The quick fill time is the same as the QA time TMqa, and in this embodiment, the quick fill time learning is referred to as QA time learning CTlrnqa.

The multiple types of K0 learning control CTlrnk0 also include a learning control that corrects the pack end pressure PRk0pk, which is the K0 oil pressure PRk0 during constant pressure standby in the "constant pressure standby during packing" phase after the "quick apply" phase, which occurs immediately before the generation of the K0 torque Tk0, that is, touch point learning CTlrnpk as packing completion oil pressure learning that corrects the pack end pressure PRk0pk, which is the K0 oil pressure PRk0 for bringing the K0 clutch 20 into a packing completion state.

In this embodiment, as the K0 hydraulic command value Spk0 in the "constant pressure standby during packing" phase, for example, the cranking hydraulic command value Spk0cr and the packing hydraulic command value Spk0pk are selectively output to the hydraulic control circuit 56 depending on the situation of the vehicle 10. The packing hydraulic command value Spk0pk is a packing K0 hydraulic command value Spk0 for adjusting the K0 hydraulic pressure PRk0 to the clutch actuator 120 so as to maintain the K0 clutch 20 in a packing completion state, that is, to maintain the K0 hydraulic pressure PRk0 at the pack end pressure PRk0pk, prior to the output of the cranking hydraulic command value Spk0cr in the "K0 cranking" phase when the engine 12 is started. The touch point learning CTlrnpk is executable when the packing hydraulic command value Spk0pk is output in the "constant pressure standby during packing" phase, and is not executed when the cranking hydraulic command value Spk0cr is output. The packing hydraulic command value Spk0pk is output when the vehicle 10 is in a state where, for example, a delayed engine start is unlikely to cause discomfort to the driver, or a start-up shock is likely to occur. A state where a delayed engine start is unlikely to cause discomfort to the driver is, for example, when the engine 12 needs to be warmed up and the start-up of the engine 12 is requested regardless of the driver's driving operation. A state where a start-up shock is likely to occur is, for example, when the engine 12 is started in cooperation with other control other than the start-up control of the engine 12, such as the shift control of the automatic transmission 24. The cranking hydraulic command value Spk0cr is output when the vehicle 10 is in a state where, for example, a delayed engine start is likely to cause discomfort to the driver, or a start-up shock is likely to occur. A state where a delayed engine start is likely to cause discomfort to the driver is, for example, when the engine 12 is requested to be started due to an increase in the amount of drive required by the driver for the vehicle 10. A situation where a start-up shock is unlikely to occur is, for example, when the engine 12 is started without coordinating with other controls other than the start control of the engine 12. In the "constant pressure standby during packing" phase, if it is determined that packing of the K0 clutch 20 is completed because a predetermined constant pressure standby duration has elapsed since the start of the "constant pressure standby during packing" phase, the phase transitions to the "K0 cranking" phase. The constant pressure standby duration in a situation where the packing hydraulic command value Spk0pk is output is basically set to a value longer than the constant pressure standby duration in a situation where the cranking hydraulic command value Spk0cr is output.

The multiple types of K0 learning control CTlrnk0 include, for example, learning control that corrects the error in the rise timing between the K0 torque Tk0 and the MG torque Tm for the K0 reaction force compensation in the "K0 cranking" phase after the "constant pressure standby during packing" phase, that is, rise time learning that corrects the difference between the transmission torque rise time when the K0 torque Tk0 rises toward the required cranking torque Tcrn and the motor torque rise time when the motor MG starts to increase the required cranking torque Tcrn. This rise time learning is also dead time learning CTlrntm that corrects the dead time TMwt from the start of the "K0 cranking" phase to the time when the K0 torque Tk0 rises relative to the cranking hydraulic pressure command value Spk0cr.

The multiple types of K0 learning control CTlrnk0 also include a learning control that corrects the variation in K0 torque Tk0 relative to the cranking hydraulic command value Spk0cr in the "K0 cranking" phase that occurs after the generation of K0 torque Tk0, that is, a transmission torque learning CTlrntk that corrects the deviation between the required cranking torque Tcrn and the K0 torque Tk0 caused by the cranking hydraulic command value Spk0cr.

The learning control unit 98 acquires each learning parameter PAlrn for performing each of the multiple types of K0 learning control CTlrnk0 as necessary, and performs K0 learning control CTlrnk0 to correct the learning value VALlrn based on the acquired learning parameter PAlrn. For example, the learning control unit 98 corrects the learning value VALlrn so that the value of the learning parameter PAlrn becomes zero, thereby converging the learning value VALlrn. The state in which the learning value VALlrn is converged is a state in which the change in the learning value VALlrn is suppressed. The learning parameter PAlrn is, for example, a numerical value that represents the degree of a phenomenon that occurs when the learning value VALlrn in the K0 learning control CTlrnk0 is not converged. The learning value VALlrn in the QA time learning CTlrnqa is, for example, the QA time TMqa. The learning value VALlrn in the touch point learning CTlrnpk is, for example, the pack end pressure PRk0pk. The learning value VALlrn in the dead time learning CTlrntm is, for example, the dead time TMwt. The learning value VALlrn in the transmission torque learning CTlrntk is, for example, the K0 torque Tk0 generated by the cranking hydraulic command value Spk0cr, and the cranking hydraulic command value Spk0cr for making the K0 torque Tk0 the required cranking torque Tcrn.

The variation in the K0 oil pressure PRk0 and the K0 torque Tk0 due to the learning value VALlrn not being converged, such as the K0 oil pressure PRk0 overshooting and generating the K0 torque Tk0 in the "quick apply" phase or the "constant pressure standby during packing" phase, which should occur before the generation of the K0 torque Tk0, or the magnitude or generation timing of the K0 torque Tk0 deviating from the target in the "K0 cranking" phase, appears as a fluctuation in the MG rotation speed Nm, such as a rise or fall. For example, if the K0 torque Tk0 is smaller than the target value or the generation timing of the K0 torque Tk0 is slower than the target, the MG torque Tm flowing to the engine 12 side is made smaller than the target, and the MG torque Tm that is relatively larger than the target, that is, the surplus MG torque Tm that does not flow to the engine 12 side, causes the MG rotation speed Nm to rise, and the variation in the K0 torque Tk0 appears as the amount of revving of the MG rotation speed Nm. The amount of revving of the MG rotation speed Nm is a positive value of the MG rotation fluctuation amount ΔNm (=Nm-Nmtgt), which is the amount of fluctuation of the MG rotation speed Nm. The above "Nmtgt" is the target rotation speed of the MG rotation speed Nm, that is, the target MG rotation speed. On the other hand, if the K0 torque Tk0 occurs in a phase that is originally before the generation of the K0 torque Tk0, the K0 torque Tk0 is larger than the target value, or the timing of the generation of the K0 torque Tk0 is earlier than the target, a part of the MG torque Tm for the drive torque Tr flows to the engine 12 side, and the MG rotation speed Nm is dropped by the MG torque Tm that is relatively smaller than the target, that is, by the shortage of the MG torque Tm for the drive torque Tr, and the variation in the K0 torque Tk0 appears as the amount of drop in the MG rotation speed Nm. The amount of drop in the MG rotation speed Nm is a negative value of the MG rotation fluctuation amount ΔNm. Thus, one example of the learning parameter PAlrn is the MG rotation fluctuation amount ΔNm.

Alternatively, for example, MG feedback control CTfbm may be performed, which is a control that compensates for the surplus or deficiency of MG torque Tm by feedback control so that the MG rotation speed Nm is maintained at the target MG rotation speed Nmtgt. When MG feedback control CTfbm is performed, the variation in K0 torque Tk0 appears as, for example, MG torque fluctuation amount ΔTm (= Tmfb - Tmb), which is the amount of fluctuation in the compensated MG torque Tmfb after the surplus or deficiency has been compensated for by the MG feedback control CTfbm. The above "Tmb" is the basic MG torque when the MG rotation speed Nm does not deviate from the target MG rotation speed Nmtgt. In this way, the MG torque fluctuation amount ΔTm is also an example of a learning parameter PAlrn.

In the control of the K0 clutch 20, which is switched to an engaged state during the start-up process of the engine 12, the "quick apply" phase is first executed to generate the K0 oil pressure PRk0, so that the change in the QA time TMqa by the QA time learning CTlrnqa or the overshoot of the K0 oil pressure PRk0 due to the QA time TMqa not converging may affect the characteristics of the pack end pressure PRk0pk, for example. Also, if the pack end pressure PRk0pk does not converge, for example, the K0 oil pressure PRk0 corresponding to the zero point of the K0 torque Tk0 may fluctuate, which may affect the correlation between the cranking oil pressure command value Spk0cr and the K0 torque Tk0. Also, if the learning value VALlrn in the transmission torque learning CTlrntk does not converge, for example, the cranking oil pressure command value Spk0cr may fluctuate, which may affect the response characteristics of the K0 torque Tk0, that is, the dead time TMwt. Therefore, depending on the order in which the individual K0 learning controls CTlrnk0 are executed among the multiple types of K0 learning controls CTlrnk0, for example, after the dead time TMwt has been converged once by the dead time learning CTlrntm, the QA time TMqa may be changed by the QA time learning CTlrnqa, and the dead time TMwt may not converge again. As a result, there is a risk that the progress of the multiple types of K0 learning controls CTlrnk0 related to the engagement of the K0 clutch 20 at engine start-up may be delayed.

Therefore, in order to prevent erroneous learning due to the mutual influence of the variations among the multiple types of K0 learning controls CTlrnk0, the priority order for executing the individual K0 learning controls CTlrnk0 is determined in advance. Also, the learning value VALlrn is converged in order starting from the K0 learning control CTlrnk0 with the highest priority, and the multiple types of K0 learning controls CTlrnk0 are advanced. Considering that the change in the QA time TMqa affects the characteristics of the pack end pressure PRk0pk as described above, the highest priority order for executing the K0 learning control CTlrnk0 is, for example, the QA time learning CTlrnqa, and the priority order for converging the learning value VALlrn is, for example, the QA time learning CTlrnqa, touch point learning CTlrnpk, transmission torque learning CTlrntk, and dead time learning CTlrntm, in order from the highest.

The priority order for converging the learning value VALlrn does not exclude the execution of two or more K0 learning controls CTlrnk0 in one engine start in the engagement control of the K0 clutch 20 accompanying the start of the engine 12. In other words, whether or not to execute the lower K0 learning control CTlrnk0 may be determined based on whether or not the learning value VALlrn in the K0 learning control CTlrnk0 with a higher priority has converged, but if the higher learning value VALlrn has not converged, the lower K0 learning control CTlrnk0 cannot be executed, and even if the higher learning value VALlrn has not converged, the lower K0 learning control CTlrnk0 may be executed depending on the state of the vehicle 10 and the needs. The priority order for converging the learning value VALlrn is such that if the learning value VALlrn in a K0 learning control CTlrnk0 with a higher priority than the K0 learning control CTlrnk0 itself has not converged, the learning value VALlrn in a K0 learning control CTlrnk0 with a lower priority, including the self, is considered not to have converged.

The learning control unit 98 executes the QA time learning CTlrnqa as the highest priority among the multiple types of K0 learning control CTlrnk0. After determining that the QA time TMqa, which is the learning value VALlrn in the QA time learning CTlrnqa, has converged, the learning control unit 98 determines whether the learning value VALlrn in at least one of the multiple types of K0 learning control CTlrnk0, the touch point learning CTlrnpk, the dead time learning CTlrntm, and the transmission torque learning CTlrntk, has converged.

Specifically, when the start control unit 92c determines that there is a request to start the engine 12, the learning control unit 98 determines whether or not to perform the K0 learning control CTlrnk0 during the current engine start control. For example, when the vehicle 10 is stable and the solenoid valve for the K0 clutch 20 and the like are determined to be not malfunctioning, the learning control unit 98 determines to perform the K0 learning control CTlrnk0. The learning control unit 98 determines whether or not the vehicle 10 is stable based on, for example, the vehicle speed V, the accelerator opening θacc, the gear position of the automatic transmission 24, the MG rotation speed Nm, and the like. For example, when the vehicle 10 is not stable or the solenoid valve for the K0 clutch 20 and the like are determined to be malfunctioning, the learning control unit 98 determines not to perform the K0 learning control CTlrnk0.

When the learning control unit 98 determines that K0 learning control CTlrnk0 should be performed, it preferentially executes the K0 learning control CTlrnk0 with the highest priority, for example, QA time learning CTlrnqa.

The learning control unit 98 determines whether the learning value VALlrn in the executed K0 learning control CTlrnk0 has converged. For example, the learning control unit 98 determines whether the learning value VALlrn has converged based on whether the value of the learning parameter PAlrn in the executed K0 learning control CTlrnk0 is smaller than a predetermined fluctuation amount for determining that the learning value VALlrn has converged. Alternatively, the learning control unit 98 determines whether the learning value VALlrn has converged based on whether the correction amount of the learning value VALlrn by the executed K0 learning control CTlrnk0 is smaller than a predetermined correction amount for determining that the learning value VALlrn has converged.

If the learning control unit 98 determines that the learning value VALlrn in the executed K0 learning control CTlrnk0 has not converged, it executes the K0 learning control CTlrnk0, which has a lower priority than the executed K0 learning control CTlrnk0, as necessary.

When the learning control unit 98 determines that the learning value VALlrn in the executed K0 learning control CTlrnk0 has converged, it executes the K0 learning control CTlrnk0 that has the next highest priority than the K0 learning control CTlrnk0 in which it has determined that the learning value VALlrn has converged.

The learning control unit 98 determines whether to terminate the K0 learning control CTlrnk0 in the current engine start control. The learning control unit 98 determines whether to terminate the K0 learning control CTlrnk0 based on, for example, whether any of the multiple types of K0 learning control CTlrnk0 in the current engine start control has been performed.

Figure 5 is a flowchart that explains the main control operations of the electronic control unit 90, and is a flowchart that explains the control operations for quickly progressing the K0 learning control CTlrnk0 related to the engagement of the K0 clutch 20 at engine start, and is executed, for example, repeatedly.

In FIG. 5, first, in step S10 (hereinafter, step will be omitted) corresponding to the function of the start control unit 92c, it is determined whether or not there is a request to start the engine 12. In other words, it is determined whether or not the start control of the engine 12 is started. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, in S20 corresponding to the function of the learning control unit 98, it is determined whether or not the K0 learning control CTlrnk0 is performed during the current engine start control. If the determination in S20 is negative, this routine is terminated. If the determination in S20 is positive, in S30 corresponding to the function of the learning control unit 98, the K0 learning control CTlrnk0 with the highest priority, for example, QA time learning CTlrnqa, is preferentially executed. Next, in S40 corresponding to the function of the learning control unit 98, it is determined whether or not the learning value VALlrn in the executed K0 learning control CTlrnk0 has converged. If the determination in S40 is negative, in S50, which corresponds to the function of the learning control unit 98, the K0 learning control CTlrnk0, which has a lower priority than the executed K0 learning control CTlrnk0, is executed as necessary. If the determination in S40 is positive, in S60, which corresponds to the function of the learning control unit 98, the K0 learning control CTlrnk0, which has the next priority than the K0 learning control CTlrnk0 for which it is determined that the learning value VALlrn has converged, is executed. Next, in S70, which corresponds to the function of the learning control unit 98, it is determined whether or not to end the K0 learning control CTlrnk0 in the current engine start control. If the determination in S70 is negative, the process returns to S40. If the determination in S70 is positive, the routine is terminated.

As described above, according to this embodiment, the QA time learning CTlrnqa among the multiple types of K0 learning control CTlrnk0 is executed with the highest priority, and after it is determined that the QA time TMqa, which is the learning value VALlrn in the QA time learning CTlrnqa, has converged, it is determined whether or not the learning value VALlrn in at least one of the touch point learning CTlrnpk, the dead time learning CTlrntm, and the transmission torque learning CTlrntk among the multiple types of K0 learning control CTlrnk0 has converged. Therefore, the QA time TMqa is quickly converged by the QA time learning CTlrnqa, and the learning value VALlrn in the K0 learning control CTlrnk0, which is different from the QA time learning CTlrnqa, is appropriately converged in a state in which it is less susceptible to the influence of the correction of the QA time TMqa. Therefore, the K0 learning control CTlrnk0 related to the engagement of the K0 clutch 20 at the time of engine start can be quickly progressed.

Next, other embodiments of the present invention will be described. In the following description, parts common to the embodiments will be given the same reference numerals and will not be described.

The learning parameter PAlrn acquired when one of the multiple types of K0 learning control CTlrnk0 is performed may contain a change due to the fact that the learning value VALlrn in a K0 learning control CTlrnk0 other than that one K0 learning control CTlrnk0 has not converged.

Therefore, the learning control unit 98 executes one of the multiple types of K0 learning controls CTlrnk0 while suppressing the influence caused by the learning value VALlrn not being converged in a K0 learning control CTlrnk0 other than the one of the multiple types of K0 learning controls CTlrnk0. For example, the K0 learning target period TMlrnk0 as a period for acquiring the learning parameter PAlrn used for one of the multiple types of K0 learning controls CTlrnk0 is determined in advance so as not to overlap with the K0 learning target period TMlrnk0 for acquiring the learning parameter PAlrn used for a K0 learning control CTlrnk0 other than the one of the multiple types of K0 learning controls CTlrnk0.

The K0 learning target period TMlrnk0 will be explained using the dead time learning CTlrntm as an example. In the "K0 cranking" phase, the components of the variation of the K0 torque Tk0 relative to the K0 hydraulic command value Spk0 include, for example, the variation of the dead time TMwt, as well as the deviation between the required cranking torque Tcrn, which is a steady variation, and the K0 torque Tk0 caused by the cranking hydraulic command value Spk0cr. The variation of the dead time TMwt may be corrected by the dead time learning CTlrntm, and the steady variation may be corrected by the transmission torque learning CTlrntk. However, if the respective K0 learning target periods TMlrnk0 overlap, for example, the learning parameter PAlrn acquired during the dead time learning CTlrntm may include a change due to the steady variation. The K0 learning target period TMlrnk0 when executing the dead time learning CTlrntm can suppress or eliminate the effects of steady-state variation if it is the period from when the K0 torque Tk0 rises toward the required cranking torque Tcrn in the "K0 cranking" phase until it approaches the required cranking torque Tcrn.

Therefore, the K0 learning target period TMlrnk0 when the dead time learning CTlrntm is executed is the period from the point when the "constant pressure waiting during packing" phase is transitioned to the "K0 cranking" phase to the point when the K0 torque Tk0 approaches the required cranking torque Tcrn. However, since the K0 torque Tk0 is a value with variation and is a value that is the target of the K0 learning control CTlrnk0, the end point of the K0 learning target period TMlrnk0 is determined using the estimated K0 torque Tk0e, which is an estimated value of the K0 torque Tk0. In other words, the K0 learning target period TMlrnk0 when the dead time learning CTlrntm is executed is the period from the start of the "K0 cranking" phase to the time when the estimated K0 torque Tk0e approaches the required cranking torque Tcrn. The estimated K0 torque Tk0e is, for example, a value indicated by a predetermined function f that reflects the response characteristics of the K0 torque Tk0 that is increased toward the required cranking torque Tcrn. The function f is a model equation that expresses, for example, the change in the estimated K0 torque Tk0e relative to the required cranking torque Tcrn as a function of a first-order lag system in the dead time and step response from zero to one.

The learning control unit 98 performs dead time learning CTlrntm based on the learning parameter PAlrn during the period from when the K0 clutch 20 is in the packing completion state until the cranking torque difference ΔTcr (= Tcrn - Tk0e), which is the difference between the estimated K0 torque Tk0e calculated using the function f and the required cranking torque Tcrn, becomes equal to or less than a predetermined torque difference ΔTcrf. The predetermined torque difference ΔTcrf is, for example, a predetermined value at which it can be determined that the estimated K0 torque Tk0e approaches the required cranking torque Tcrn.

As described above, according to this embodiment, the dead time learning CTlrntm is performed based on the learning parameter PAlrn during the period from when the K0 clutch 20 is in the packing completion state until the cranking torque difference ΔTcr becomes equal to or less than the predetermined torque difference ΔTcrf, so that the dead time learning CTlrntm can be appropriately performed while suppressing the influence of the deviation between the required cranking torque Tcrn and the K0 torque Tk0 caused by the cranking hydraulic pressure command value Spk0cr.

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

For example, in the above-mentioned embodiment, when multiple types of K0 learning control CTlrnk0 can be executed at one engine start, if the previous K0 learning control CTlrnk0 in terms of the transition order of each phase in the K0 control phase definition Dphk0 cannot be learned satisfactorily for some reason, the learning parameter PAlrn in the subsequent K0 learning control CTlrnk0 cannot be detected properly, which may lead to erroneous learning. Therefore, it is possible to not execute the K0 learning control CTlrnk0 subsequent to the K0 learning control CTlrnk0 that could not be learned satisfactorily.

In addition, in the above-mentioned embodiment, if there are cases where, for example, MG feedback control CTfbm is not performed depending on the running state of the vehicle 10 or the phase in the K0 control phase definition Dphk0, the acquired learning parameters PAlrn may be appropriately switched for each of the multiple types of K0 learning control CTlrnk0.

In addition, in the above-mentioned embodiment, the learning parameter PAlrn may be a numerical value representing the degree of a phenomenon caused by the learning value VALlrn in the K0 learning control CTlrnk0 not being converged, or a numerical value representing the degree of a phenomenon caused by the variation of the K0 hydraulic pressure PRk0 relative to the K0 hydraulic pressure command value Spk0, and is not limited to the MG rotation fluctuation amount ΔNm or the MG torque fluctuation amount ΔTm.

In the above embodiment, the engine 12 is started in a manner in which the engine 12 is ignited in accordance with the cranking of the engine 12 in a transitional state in which the K0 clutch 20 is switched from a released state to an engaged state, and the engine 12 itself increases the engine rotation speed Ne, but this is not limited to the above embodiment. For example, the engine 12 may be started by cranking the engine 12 until the K0 clutch 20 is fully engaged or close to being fully engaged, and then igniting the engine 12. When the vehicle 10 is stopped and the MG rotation speed Nm is zero, a starting method can be adopted in which the engine 12 is cranked by the electric motor MG in the fully engaged state of the K0 clutch 20, and then ignited. In addition, if the vehicle 10 is equipped with a starter, which is a motor dedicated to cranking the engine 12, when the vehicle 10 is stopped and the MG rotation speed Nm is set to zero, for example, when the outside air temperature is extremely low and cranking by the electric motor MG is insufficient or impossible, a starting method can be adopted in which the engine 12 is cranked by the starter and then ignited.

In addition, in the above embodiment, a planetary gear type automatic transmission is exemplified as the automatic transmission 24, but this is not limited to the embodiment. The automatic transmission 24 may be a synchronous mesh type parallel two-shaft automatic transmission including a known DCT (Dual Clutch Transmission), a known belt type continuously variable transmission, etc.

In addition, in the above-mentioned embodiment, the torque converter 22 is used as the fluid transmission device, but this is not limited to the embodiment. For example, instead of the torque converter 22, other fluid transmission devices such as a fluid coupling that does not have a torque amplifying effect may be used as the fluid transmission device. Alternatively, the fluid transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

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

10: Vehicle 12: Engine 14: Drive wheels 20: K0 clutch (clutch)
56: Hydraulic control circuit 90: Electronic control device (control device)
92c: Start control unit 94: Clutch control unit 98: Learning control unit 120: Clutch actuator MG: Electric motor

Claims (2)

A control device for a vehicle including an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be capable of transmitting power, a clutch whose control state is switched by controlling a hydraulic clutch actuator provided between the engine and the electric motor in the power transmission path, and a hydraulic control circuit that supplies a regulated hydraulic pressure to the clutch actuator,
a start control unit that controls the electric motor so as to increase an output torque of the electric motor by a necessary cranking torque, which is a torque necessary for cranking the engine, when starting the engine, and also controls the engine so as to start operation of the engine;
a clutch control unit that outputs, as a hydraulic pressure command value for supplying the hydraulic pressure during an engagement transition in which a control state of the clutch is switched from a released state to an engaged state, to the hydraulic control circuit, a cranking hydraulic pressure command value that adjusts the hydraulic pressure to the clutch actuator so that the clutch transmits the required cranking torque, and outputs, prior to the output of the cranking hydraulic pressure command value, to the hydraulic control circuit, as the hydraulic pressure command value, a rapid filling hydraulic pressure command value that improves responsiveness of the hydraulic pressure to the clutch actuator so that the clutch is quickly brought to a packing completion state in which a pack clearance of the clutch is closed;
a learning control unit that performs a plurality of types of learning control to correct a relationship that represents a correlation between the hydraulic pressure during the engagement transition of the clutch and the hydraulic pressure command value;
Contains
The learning control unit is
Among the plurality of types of learning controls, a quick fill time learning for correcting a quick fill time at which the quick fill hydraulic pressure command value is output is executed with the highest priority,
A vehicle control device characterized in that, after determining that the rapid fill time, which is a learned value in the rapid fill time learning, has converged, the control device determines whether or not a learned value in at least one of the multiple types of learning controls has converged: packing completion hydraulic pressure learning, which corrects the hydraulic pressure to bring the clutch into the packing completion state; rise time point learning, which corrects the difference between the transmission torque rise time point at which the transmission torque of the clutch rises toward the required cranking torque and the electric motor torque rise time point at which the electric motor begins to increase the required cranking torque; and transmission torque learning, which corrects the difference between the required cranking torque and the transmission torque of the clutch generated by the cranking hydraulic pressure command value. The control device for a vehicle according to claim 1, characterized in that the learning control unit performs the rising time point learning based on a numerical value representing the degree of a phenomenon caused by the learning value in the learning control not being converged during the period from when the clutch is in the packing completion state until the difference between the estimated value of the transmission torque calculated using a predetermined function reflecting the response characteristics of the transmission torque of the clutch that is increased toward the required cranking torque and the required cranking torque becomes equal to or less than a predetermined value at which it can be determined that the estimated value of the transmission torque is approaching the required cranking torque.

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