Control device

Abstract

Control device (1) for controlling a vehicle drive system (3) in which an engagement device (32), a rotary electric machine (33) and a multi-stage automatic transmission (35) are provided in a power transmission path connecting an internal combustion engine (EG) to wheels (W), wherein when the engagement device (32) is engaged to start the internal combustion engine (EG) during a shifting operation of the multi-stage automatic transmission (35) in a state in which a vehicle is moving with a torque of the rotary electric machine (33) and the engagement device (32) is in a disengaged state, the control device (1) causes a rotational speed (Nmg) of the rotary electric machine (33) to change according to a predetermined first change pattern after the rotational speed (Nmg) of the rotary electric machine (33) changes from a pre-shift synchronous speed (Nsynb) in conjunction with a progress of the shifting operation until a first synchronous range is reached,which is determined on the basis of a rotational speed (Neg) of the internal combustion engine (EG), wherein the pre-synchronous speed (Nsynb) is the rotational speed (Nmg) of the rotary electric machine (33) in a switching gear that is set up before the switching operation is started, the rotational speed (Nmg) of the rotary electric machine (33) in the switching gear that is set up after the switching operation is completed is defined as a post-synchronous speed (Nsyna), and after the rotational speed (Nmg) of the rotary electric machine (33) reaches the first synchronous range until an engagement instruction pressure for the engagement device (32) is equal to a predetermined direct engagement pressure and the engagement device (32) reaches a direct engagement state, the control device (1) causes the rotational speed (Nmg) of the rotary electric machine (33) to change according to a second change pattern that is set to have a differential rotation (ΔNs) relative to the post-synchronous speed (Nsyna).

Description

The present invention relates to a control device for controlling a vehicle drive system. STATE OF THE ART Hybrid vehicles, which use both an internal combustion engine and a rotary electric machine as a source for driving the wheels, are in practical use. An example of a vehicle drive system used in such hybrid vehicles is disclosed in JP 2007-99 141 A. The vehicle drive system of JP 2007-99 141 A comprises an engagement device (a first clutch 6), a rotary electric machine (a motor / generator 5), and a multi-stage automatic transmission (an automatic transmission 3) arranged in a power transmission path that connects an internal combustion engine (a machine 1) to wheels (right and left rear wheels 2). The vehicle propulsion system of JP 2007-99 141 A is structured to achieve the following modes: an electric driving mode, which allows the vehicle to travel using the torque of the rotary electric motor, with the engagement device in a disengaged state; and a hybrid driving mode, which allows the vehicle to travel using the torques of the internal combustion engine and the rotary electric motor, with the engagement device in an engaged state. When switching from the electric driving mode to the hybrid driving mode, a control device for controlling the vehicle propulsion system of JP 2007-99 141 A brings the engagement device into a slip-engaged state and performs a start control of the internal combustion engine using the torque of the rotary electric motor.At this time, the transmission torque capability of the engagement device, which is brought into the slip engagement state, is set in accordance with the magnitude of a torque required to raise (increase) the rotational speed of the internal combustion engine. US 2014 / 0222270A1 discloses a control device for controlling a vehicle propulsion system in which an internal combustion engine coupling and disconnect clutch, located in a power transmission path between an internal combustion engine and an electric motor, is brought into a specific slip-engagement state when an internal combustion engine start control is performed. This is achieved by changing the electric motor speed at a predetermined rate lower than the electric motor speed during normal downshifting of an automatic transmission, such that the internal combustion engine speed is increased to the electric motor speed Nmg at a time t4 during an inertia phase of the automatic transmission. This reduces the degree of slip of the internal combustion engine coupling and disconnect clutch during the internal combustion engine start control. In conventional vehicles that do not have a rotary electric motor in the power transmission path between an internal combustion engine and a multi-stage automatic transmission, the engine speed is actively modified by a torque control system during a multi-stage automatic transmission shift. This allows the input speed of the multi-stage automatic transmission to approach its post-shift speed (the speed after the shift). This control is performed to reduce the shock transmitted to the wheels and to shorten the shift time. Normally, the difference between a setpoint for the engine's torque control and the actual output torque is small, and the engine speed is directly matched to the input speed of the multi-stage automatic transmission.Therefore, it is common to use a feedforward control (control) for such torque control of an internal combustion engine. However, as in the vehicle drive system of JP 2007-99141A, in a structure where an engagement device and a rotary electric motor are provided in a power transmission path between an internal combustion engine and a multi-stage automatic transmission, the engagement device is brought into a slip-engage state in some cases, for example, when a start control of the internal combustion engine is executed. In such cases, it is difficult to set the input speed of the multi-stage automatic transmission, which is performing a shift operation, to a target value by means of feedforward control of the torques input to the multi-stage automatic transmission, in particular the torques of the internal combustion engine and the rotary electric motor. This is because the transmission torque capability of the engagement device, which is brought into the slip-engage state, can deviate from or fluctuate with a target value.In other words, regardless of whether the feedforward control of the internal combustion engine and rotary electric motor torques is implemented as intended, if the torque transmission capability of the engagement device, which is brought into the slip engagement state, is not controlled as intended, the input torque of the multi-stage automatic transmission will deviate from its target value, and consequently, the input speed of the multi-stage automatic transmission performing the shift operation will fluctuate. As a result, drivability may deteriorate. SUMMARY OF THE INVENTION The object of the present invention is to provide a control device for controlling a vehicle drive system, with which good drivability can be maintained even when a shifting operation of an automatic transmission of the vehicle drive system coincides with a start control of an internal combustion engine of the vehicle drive system. The object of the present invention is achieved by a control device for controlling a vehicle drive system with the features of claim 1. Advantageous embodiments of the present invention are defined in the dependent claim. According to an advantage of the present invention, when the shifting operation coincides with the start-up control of the internal combustion engine, a speed control of the rotary electric motor is performed according to the first modification, after the speed of the rotary electric motor changes from the pre-sequence synchronous speed until the first synchronous range of the speed of the internal combustion engine is reached. If a difference occurs between an actual value and a target value of the transmission torque capability of the engagement device, the speed control of the rotary electric motor corrects the output torque of the rotary electric motor in accordance with the difference in order to maintain a stable rotational acceleration of an input component of the multi-stage automatic transmission. Thus, good drivability is maintained. Other features, effects and advantages according to the present invention are described in detail below with reference to the following description of exemplary, non-limiting embodiments in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of a vehicle drive system according to one embodiment. Fig. 2 is a block diagram showing a schematic structure of a control device. Fig. 3 is a flowchart showing the sequence of a start-up switching control. Fig. 4 is a flowchart showing the sequence of a special switching control. Fig. 5 is a timing diagram showing an example of the start-up switching control. Fig. 6 is a timing diagram showing a comparative example of the start-up switching control. Fig. 7 is a timing diagram showing another example of the start-up switching control. Fig. 8 is a schematic diagram of a vehicle drive system according to another embodiment. Fig. 9 is a schematic diagram of a vehicle drive system according to another embodiment. MODES FOR EXECUTING THE INVENTION An embodiment of a control device is described below. A control device 1 is a control device for a vehicle drive system and controls a vehicle drive system 3. The vehicle drive system 3, which is to be controlled by the control device 1, is a drive system (hybrid vehicle drive system) for driving a vehicle (a hybrid vehicle) that is equipped with both an internal combustion engine EG and a rotary electric machine 33, each of which serves as a drive source for wheels W. The vehicle drive system 3 is structured (constructed) as a vehicle drive system for driving a parallel hybrid vehicle that employs a parallel hybrid system. In the following description, the term "drive-coupled" refers to a state in which two rotating elements are coupled to transmit a driving force (identical to the concept of torque) between them. This concept encompasses a state in which two rotating elements are coupled to rotate together, and a state in which two rotating elements are coupled by at least one transmission component to transmit a driving force between them. Such a transmission component comprises various types of components (a shaft, a gear mechanism, a belt, etc.) that transmit rotation while maintaining or changing the rotational speed, and may include an engagement device (a friction engagement device, a comb engagement device, etc.) that selectively transmits rotation and a driving force. The "rotary electromachine" is used as a concept that includes a motor (an electric motor), a generator (an electric generator) and a motor-generator that can operate as either a motor or a generator when required. With regard to the engagement state of a friction engagement device, an "engagement state" refers to a condition in which a transmission torque capability is generated by the friction engagement device. The transmission torque capability is the maximum torque that the friction engagement device can transmit through friction. The magnitude of the transmission torque capability is determined relative to a pressure (an engagement pressure) that presses a pair of engagement components (an input engagement component and an output engagement component) of the friction engagement device against each other. The "engagement state" includes a "direct engagement state," in which there is no speed difference (slipping) between the pair of engagement components, and a "slipping engagement state," in which there is a speed difference between the pair of engagement components. An "out-of-engagement state" refers to a condition in which no transmission torque capability is generated by the friction engagement device.The “disengagement state” comprises a state in which, although the control device 1 does not instruct that the friction engagement device generate the transmission torque capability, the transmission torque capability is generated by dragging between the engagement components (friction components). As shown in Fig. 1, the vehicle drive system 3 comprises a decoupling engagement device 32, the rotary electric motor 33, and a gearbox 35, which are arranged in a power transmission path that connects the internal combustion engine EG to the wheels W. To transmit rotation and a driving force between the components in the power transmission path, the vehicle drive system 3 comprises an input component 31, a switching input component 34, and an output component 36. In the power transmission path, the input component 31, the decoupling engagement device 32, the rotary electric motor 33, the switching input component 34, the gearbox 35, and the output component 36 are arranged in the aforementioned order from the side of the internal combustion engine EG. The input component 31 is drive-coupled to the internal combustion engine EG. The internal combustion engine EG is a motor (a gasoline engine, a diesel engine, etc.) that is driven by the combustion of fuel within the engine and thus generates power. The input component 31 is implemented, for example, as a shaft component. The input component 31 is drive-coupled to an internal combustion engine output component (for example, a crankshaft), which is an output component of the internal combustion engine EG. The input component 31 can be coupled to the internal combustion engine output component either directly or via another component, such as a damper. The input component 31 is drive-coupled to the rotary electric motor 33 via the decoupling engagement device 32. The decoupling engagement device 32 selectively decouples the input component 31 and the rotary electric machine 33. In other words, the decoupling engagement device 32 allows the internal combustion engine EG and the rotary electric machine 33 to be released from the drive-coupled state. The decoupling engagement device 32 acts / serves as an engagement device for decoupling an internal combustion engine. According to the present embodiment, the decoupling engagement device 32 is a friction engagement device. For example, a wet multi-plate clutch can be used as the decoupling engagement device 32. According to the present embodiment, the decoupling engagement device 32 corresponds to an "engagement device". The rotary electric machine 33 has a stator attached to a housing, which is a non-rotating component, and a rotor rotatably supported radially within the stator. The rotary electric machine 33 is connected to an energy storage device via an inverter. The rotary electric machine 33 receives an electric current from the energy storage device to perform power operation, or supplies an electric current to the energy storage device, generated by the torque of the internal combustion engine EG and the inertial force in a vehicle, to charge the energy storage device. The rotor of the rotary electric machine 33 is coupled to and rotates with the switching input component 34. The switching input component 34 is, for example, a shaft component. The switching input component 34, which rotates with the rotor, is drive-coupled to the gearbox 35. The transmission 35 is structured (constructed) as a multi-stage automatic transmission. According to the present embodiment, the transmission 35 has a planetary gear mechanism and several shift engagement devices 35C. The shift engagement devices 35C have one or more clutches 35X and one or more brakes 35Y. According to the present embodiment, the clutch 35X and the brake 35Y of the shift engagement device 35C are friction engagement devices. For example, a wet multi-plate clutch and a wet multi-plate brake can be used as the shift engagement devices 35C. It should be noted that the shift engagement devices 35C can have one or more one-way clutches. The transmission 35 can selectively engage any gear from several shift gears in accordance with the engagement state of each of the shift engagement devices 35C. For example, the transmission 35 selectively engages two of the several shift engagement devices 35C and engages a shift gear that corresponds to a combination in the engaged shift engagement device 35C. The transmission 35 changes the rotational speed of the input switching component 34 with a gear ratio corresponding to the engaged shift gear and transmits the rotational speed to the output component 36. The "gear ratio" is a ratio of the rotational speed of the input switching component 34 to the rotational speed of the output component 36 and is a value calculated by dividing the rotational speed of the input switching component 34 by the rotational speed of the output component 36. The output component 36 is, for example, a shaft component. The output component 36 is drive-coupled to the pair of right and left wheels W via a differential gear device 37. A torque transmitted to the output component 36 is distributed by the differential gear device 37 and transmitted to the two right and left wheels W. Thus, the vehicle drive system 3 transmits the torque from the internal combustion engine EG and / or the rotary electric motor 33 to enable the vehicle to move. The control device 1 serves / acts as a core component for controlling the operation of each section of the vehicle drive system 3. As shown in Fig. 2, the control device 1 has an integrated control section 11, a rotary electromachine control section 12, and an engagement control section 13. These functional sections are executed by software (programs) stored in a storage medium, such as memory, by additional hardware, such as a computer circuit, or by both software and hardware. The functional sections can exchange information with each other. Furthermore, the control device 1 can determine information about the results detected (captured) by various sensors (from a first sensor 51 to a third sensor 53) mounted on parts (components) of a vehicle equipped with the vehicle drive system 3.The first sensor 51 detects (records) the rotational speed of the input component 31 or of a component (for example, the internal combustion engine EG) that rotates synchronously with the input component 31. The term "synchronous rotation" means that the corresponding rotating components rotate together or rotate at proportional speeds. The second sensor 52 detects (records) the rotational speed of the switching input component 34 or of a component (for example, the rotary electric motor 33) that rotates synchronously with the switching input component 34. The third sensor 53 detects (records) the rotational speed of the output component 36 or of a component (for example, the wheels W) that rotates synchronously with the output component 36. The control device 1 can calculate a vehicle speed based on the result recorded by the third sensor 53.Additionally, the control device 1 can determine information about the accelerator actuation extent, the brake actuation extent and the amount of current stored in the current storage device. The integrated control section 11 performs a control operation that integrates the various types of control (including torque control, speed control, and engagement control) of the internal combustion engine EG, the rotary electric machine 33, the decoupling engagement device 32, the transmission 35 (the shift engagement devices 35C), etc., as a whole within the vehicle. Based on sensor data (information primarily about the degree of accelerator actuation and the vehicle speed), the integrated control section 11 calculates the required vehicle torque necessary to propel the vehicle (the wheels W). Furthermore, the integrated control section 11 determines a driving mode based on sensor data (information primarily about the accelerator pedal actuation force, vehicle speed, and the amount of current stored in the energy storage device). According to the present embodiment, the driving mode selectable by the integrated control section 11 includes an electric driving mode (hereinafter referred to as an "EV mode") and a hybrid driving mode (hereinafter referred to as an "HEV mode"). The EV mode is a mode that transmits the torque of only the rotary electric motor 33 to the wheels W to enable the vehicle to move. The HEV mode is a mode that transmits the torque of both the internal combustion engine EG and the rotary electric motor 33 to the wheels W to enable the vehicle to move. The integrated control section 11 determines, based on the selected driving mode, sensor data, etc., a torque (required internal combustion engine torque) to be output by the internal combustion engine EG and a torque (required rotary electric motor torque) to be output by the rotary electric motor 33. Based on the selected driving mode, sensor data, etc., the integrated control section 11 also determines the engagement state of the decoupling device 32, a target gear ratio to be set by the transmission 35, etc. According to the exemplary embodiment, the integrated control section 11 is structured to execute (handle) an internal combustion engine start control when switching from EV mode to HEV mode. The internal combustion engine start control is a control that moves the clutch engagement device 32 from the disengaged state to a slip-engaged state when the vehicle is driving in EV mode, thus starting the internal combustion engine EG using the torque of the rotary electric motor 33. According to the present embodiment, the control device 1 (the integrated control section 11) controls the operating point (output torque and speed) of the internal combustion engine EG via an internal combustion engine control device 20. The internal combustion engine control device 20 can select either torque control or speed control of the internal combustion engine EG in accordance with the driving condition of the vehicle. Torque control is a control that provides the internal combustion engine EG with a command indicating a target torque, and that causes the output torque of the internal combustion engine EG to follow the target torque. Speed ​​control is a control that provides the internal combustion engine EG with a command indicating a target speed, and that determines an output torque that causes the speed of the internal combustion engine EG to follow the target speed. The rotary electric motor control section 12 controls the operating point (output torque and speed) of the rotary electric motor 33. The rotary electric motor control section 12 can select either torque control or speed control of the rotary electric motor 33 according to the vehicle's driving condition. Torque control is a control that provides the rotary electric motor 33 with an instruction indicating a target torque, causing the output torque of the rotary electric motor 33 to follow the target torque. Speed ​​control is a control that provides the rotary electric motor 33 with an instruction indicating a target speed, determining an output torque that causes the speed of the rotary electric motor 33 to follow the target speed. The engagement control section 13 controls the engagement state of the decoupling engagement device 32 and the engagement state of the multiple shift engagement devices 35C that the transmission 35 has. According to the present embodiment, the decoupling engagement device 32 and the multiple shift engagement devices 35C are hydraulically driven friction engagement devices. The engagement control section 13 controls, via a hydraulic control device 41, a hydraulic pressure that is supplied to each of the decoupling engagement device 32 and the shift engagement devices 35C in order to control the engagement state of the decoupling engagement device 32 and the shift engagement device 35C. The engagement pressure of each of the engagement devices changes in proportion to the magnitude of the hydraulic pressure supplied to that engagement device. Accordingly, the magnitude of the transmission torque capability generated by each of the engagement devices changes in proportion to the magnitude of the hydraulic pressure supplied to that respective engagement device. In accordance with the supplied hydraulic pressure, each of the engagement devices is brought into any of the following engagement states: that is, the direct engagement state; the slip engagement state; and the disengagement state. The hydraulic pressure control device 41 includes a hydraulic control valve (for example, a linear solenoid valve) for regulating the hydraulic pressure of a hydraulic oil supplied by an oil pump (not shown).For example, the oil pump can be a mechanical pump driven by the input component 31 or by the switching input component 34, or it can be an electrically driven pump driven by a rotary electric motor belonging to the pump. The hydraulic control device 41 regulates the opening degree of the hydraulic control valve in accordance with a hydraulic instruction from the engagement control section 13, thus supplying the hydraulic oil at a hydraulic pressure corresponding to the hydraulic instruction to each of the engagement devices. The engagement control section 13 controls the engagement state of the decoupling engagement device 32, thus establishing the driving mode determined by the integrated control section 11. For example, when EV mode is established, the engagement control section 13 moves the decoupling engagement device 32 into the disengaged state, and when HEV mode is established, the engagement control section 13 moves the decoupling engagement device 32 into the direct engagement state. Furthermore, when switching from FV mode to HEV mode, the engagement control section 13 first moves the decoupling engagement device 32 into the slip engagement state and then into the direct engagement state. The engagement control section 13 controls the engagement state of each of the multiple switching engagement devices 35C, so that a target switching sequence, determined by the integrated control section 11, is established. The engagement control section 13 brings two of the switching engagement devices 35C into the direct engagement state corresponding to the target switching sequence, while all other switching engagement devices 35C are brought into the disengagement state.Furthermore, if a change in the target shift gear occurs while the vehicle is operating in EV or HEV mode, the engagement control section 13, based on the difference between the shift engagement devices 35C that must be brought into the direct engagement state before and after the change in the target shift gear occurs, switches specific shift engagement devices 35C from the direct engagement state to the disengaged state and switches other specific shift engagement devices 35C from the disengaged state to the engaged state. In the following description, the term "disengaged engagement device 35R" refers to the shift engagement device 35C that has just been brought into the disengaged state during the shift operation, and the term "coupled engagement device 35A" refers to the shift engagement device 35C that has just been brought into the engaged state (coupled state) during the shift operation. According to the present embodiment, the control device 1 executes a start-coupling switching control when the decoupling engagement device 32 is engaged to start the internal combustion engine EG during the shifting operation of the transmission 35 in a state where the vehicle is driving with the torque of the rotary electric machine 33 and the decoupling engagement device 32 is disengaged. The control device 1 executes the start-coupling switching control, for example, when a shift control involving a change in the target gear coincides with the start control of the internal combustion engine EG to switch to HEV mode while the vehicle is driving in EV mode. The start-coupling switching control is executed according to the sequences shown in Figures 3 and 4. First, it is determined whether the driving mode, as determined by the integrated control section 11, is EV mode (step #01). If the vehicle is in EV mode (Yes in #01), it is determined whether the integrated control section 11 has changed the target gear (#02). If it is determined that a shift operation is taking place (Yes in #02), the integrated control section 11 changes the driving mode to HEV mode (#03). If the driving mode is not changed to HEV mode, so that no request to start the internal combustion engine occurs (No in #03), normal shift control is executed (#04). Normal shift control causes the shift operation to proceed while the engagement pressures of the disengaged engagement device 35R and the coupled engagement device 35A are controlled according to normal practice. In contrast, if the driving mode is changed to HEV mode during shifting while the vehicle is driving in EV mode, such that a request to start the internal combustion engine EG occurs (Yes in #03), a special shift control, which is a characteristic of the control device 1 according to the present embodiment, is executed (#05). An example of the special shift control is described below with reference to a timing diagram from Fig. 5. Assuming that the target shift gear is changed at time t01, the coupled engagement device 35A begins to engage at time t02, and then the disengaged engagement device 35R begins to disengage.Assuming that a request to start the internal combustion engine EG occurs during switching operation before a time t03 at which the disengaged engagement device 35R reaches the disengagement state, the coupled engagement device 35A is held in the slip engagement state. As the actual value of the torque transmission capacity of the coupled engagement device 35A gradually increases in the slip engagement state during the shifting operation, the rotational speed of the switching input component 34 changes from a pre-shift synchronous speed (synchronous speed before the shifting operation) Nsynb (immediately, promptly). The pre-shift synchronous speed Nsynb here refers to an imaginary rotational speed of the switching input component 34, calculated based on the rotational speed of the output component 36, detected by the third sensor 53, and the gear ratio of the shift gear established before the shift. Specifically, the pre-shift synchronous speed Nsynb is calculated by multiplying the rotational speed of the output component 36 by the rotational speed of the shift gear established before the shift.Since the switching input component 34 rotates with the rotary electric machine 33, the pre-sequence synchronous speed Nsynb at a time when a change in the speed of the switching input component 34 begins is the same as a speed Nmg of the rotary electric machine 33 in the switching stage that is set up before the start of the switching operation. In the specific switching control, it is first determined whether the rotational speed Nmg of the rotary electric machine 33 changes from the upstream synchronous speed Nsynb in connection with the progress of the switching operation. In the present example, it is determined whether a difference (an absolute value) between the rotary switching synchronous speed Nsynb, calculated on the basis of the rotational speed of the output component 36 detected by the third sensor 53, and the rotational speed Nmg of the rotary electric machine 33 detected by the second sensor 52, is greater than or equal to a first determining differential speed ΔN1 (#11). It is preferred that the first determining differential speed ΔN1 is set to an arbitrary value, for example, between 20 and 100 rpm. Then, if a positive determination is made at time t03 (Yes in #11), a first rotation change control is executed (#12) to cause the rotational speed Nmg of the rotary electric machine 33 to change according to a first change pattern. The first change pattern is a pattern in which the rotational speed changes at a constant rate of change over time. During a ramp-up, as in this example, the first change pattern is a pattern in which the rotational speed decreases at a constant rate of change over time. In a first phase P1, the rotary electric machine control section 12 provides the rotary electric machine 33 with an instruction indicating a target speed that decreases at a constant rate of change over time and controls the rotary electric machine 33 so that its rotational speed follows the target speed. It should be noted that the first phase P1 corresponds to an inertia phase of the normal switching control. After time t03, the decoupling engagement device 32 is brought into the slip-engaged state. At this time, the transmission torque capacity of the decoupling engagement device 32 is set to the magnitude of the torque required to increase the rotational speed of the stationary internal combustion engine EG. The rotational speed of the internal combustion engine EG increases with the torque of the rotary electric motor 33, which is transmitted via the decoupling engagement device 32. Subsequently, when the rotational speed of the internal combustion engine EG reaches a combustion start speed, a spark ignition occurs, causing the internal combustion engine EG to rotate independently. The speed control is executed until the rotational speed Nmg of the rotary electric machine 33 reaches a first synchronous range, which is determined based on the rotational speed Neg of the internal combustion engine EG. The first synchronous range is a speed range in which the rotational speed Nmg of the rotary electric machine 33 rotates synchronously with, or substantially synchronously with, the rotational speed Neg of the internal combustion engine EG. The first synchronous range can be a speed range from a speed that is lower than the rotational speed Neg of the internal combustion engine EG by a second determining differential speed ΔN2 to a speed that is higher than the rotational speed Neg of the internal combustion engine EG by a second determining differential speed ΔN2. It is preferred that the second determining differential speed ΔN2 is set to an arbitrary value, for example, between 20 and 100 rpm.In the present example, during the execution of the first rotation change control, it is determined whether a difference (an absolute value) between the rotational speed Neg of the internal combustion engine EG, detected by the first sensor 51, and the rotational speed Nmg of the rotary electric machine 33, detected by the second sensor 52, is less than or equal to the second determining differential speed ΔN2 (#13). For example, if a positive determination is made at time t04 (Yes in #13), then a second rotation change control is executed (#14) to cause the rotational speed Nmg of the rotary electric machine 33 to change according to a second change pattern. The second change pattern is a pattern that maintains a differential rotation (a slip differential rotation ΔNs in the present example) relative to a post-shift synchronous speed (rotational speed after the shift operation) Nsyna within a constant range. The second change pattern is a pattern that is dynamically set in accordance with a change in vehicle speed. It should be noted that the slip differential rotation ΔNs is set to a value (for example, between 100 and 300 rpm) that is significantly larger than the second determination differential speed ΔN2 and a third determination differential speed ΔN3, which is described below.The post-switching synchronous speed Nsyna is an imaginary speed of the switching input component 34, calculated based on the speed of the output component 36, detected by the third sensor 53, and the gear ratio of the switching gear set up after switching. Specifically, the post-switching synchronous speed Nsyna is calculated by multiplying the speed of the output component 36 by the gear ratio of the switching gear set up after switching. Since the switching input component 34 rotates with the rotary electric machine 33, the post-switching synchronous speed Nsyna is equal to an imaginary speed of the rotary electric machine 33 in a switching gear set up after the switching operation is complete.In a second phase P2, which follows the first phase P1, the rotary electric machine control section 12 provides the rotary electric machine 33 with an instruction indicating a target speed, which is set to achieve the slip differential rotation ΔNs relative to the downstream synchronous speed Nsyna. The rotary electric machine control section 12 then controls the rotary electric machine 33 so that its speed follows the target speed. When the second rotation change control is executed, the decoupling engagement device 32 is brought into the direct engagement state. In other words, during the execution of the second rotation change control, it is determined whether the decoupling engagement device 32 reaches the direct engagement state (#15), and the second rotation change control is executed until the decoupling engagement device 32 reaches the direct engagement state. It should be noted that whether or not the decoupling engagement device 32 reaches the direct engagement state can be determined based on whether an engagement instruction pressure for the decoupling engagement device 32 is equal to a predetermined direct engagement pressure. For example, if a positive determination is made at time t05 (Yes in #15), a third rotation change control is executed (#16) to cause the rotational speed Nmg of the rotary electric machine 33 to change according to a third change pattern. The third change pattern here refers to a pattern in which the rotational speed changes towards the downstream synchronous speed Nsyna at a constant rate of change. During an upshift as in the present embodiment, the third change pattern is a pattern in which the rotational speed decreases towards the downstream synchronous speed Nsyna at a constant rate of change.In a third phase P3, which follows the second phase P2, the rotary electromachine control section 12 provides the rotary electromachine 33 with an instruction indicating a target speed that decreases towards the downstream synchronous speed Nsyna at a constant rate of time change, and the rotary electromachine 33 is controlled so that the speed of the rotary electromachine 33 follows the target speed. The third speed control is executed until the rotational speed Nmg of the rotary electric machine 33 reaches a second synchronous range, which is determined based on the downstream synchronous speed Nsyna. The second synchronous range is a speed range in which the rotational speed Nmg of the rotary electric machine 33 rotates synchronously with, or substantially synchronously with, the downstream synchronous speed Nsyna. The second synchronous range can be a speed range, for example, from a speed that is lower than the downstream synchronous speed Nsyna by a third determining differential speed ΔN3 to a speed that is higher than the downstream synchronous speed Nsyna by a third determining differential speed ΔN3. It is preferred that the third determining differential speed ΔN3 is set to an arbitrary value, for example, between 20 and 100 rpm.In the present example, during the execution of the third rotation change control, it is determined whether a difference (an absolute value) between the downstream synchronous speed Nsyna, calculated on the basis of the speed of the output component 36, detected by the third sensor 53, and the speed Nmg of the rotary electric machine 33, detected by the second sensor 52, is less than or equal to the third determining differential speed ΔN3 (#17). For example, if a positive determination is made at time t06, the coupled engagement device 35A is brought into the direct engagement state and then the start-coupling switching control ends. According to the control characteristics of the control device 1 of the present embodiment, the speed control (the first speed change control described above) of the rotary electric machine 33 is executed in the first phase P1, which corresponds to the inertia phase of the normal switching control, during the start-up switching control. If a difference occurs between the actual value and the setpoint of the transmission torque capability of the decoupling engagement device 32, the first speed change control corrects the output value of the rotary electric machine 33 in accordance with the difference (see the duration from time t03 to t04 in Fig. 5). Consequently, the rotational acceleration of the switching input component 34 is kept constant in accordance with a change in the speed Nmg of the rotary electric machine 33. Thus, good drivability is maintained. Fig. 6 presents a comparative example in which the torque control of the rotary electric machine 33 is implemented in a first phase P1 to ensure that the rotary electric machine 33 outputs a torque equivalent to the transmission torque capacity of the decoupling engagement device 32. In this case, drivability deteriorates because the rotational acceleration of the switching input component 34 fluctuates due to the difference between the actual value and the target value of the rotational transmission capacity of the decoupling engagement device 32. As can be easily seen by comparing Fig. 5 and Fig. 6, the start-coupling switching control according to the present embodiment enables an improvement in switching quality when the difference in the transmission torque capacity of the decoupling engagement device 32 occurs. (Further examples) (1) The example used to describe the embodiment is based primarily on the assumption that an upshift coincides with the start control of the internal combustion engine EG. However, without this being a limitation for such a structure, if, for example, a downshift coincides with the start control for the internal combustion engine EG, the start-coupling switching control can be implemented in the same way. Fig. 7 shows a timing diagram of the start-coupling switching control in this case. Even at the time of downshifting, it is possible to maintain good drivability by executing the first speed change control after the speed Nmg of the rotary electric machine 33 changes from the upstream synchronous speed Nsynb in conjunction with the progress of the switching operation, until the first synchronous range is reached.(2) In the example used to describe the embodiment, the first speed control causes the rotational speed Nmg of the rotary electric machine 33 to change at a constant rate of change over time. However, without being limiting for such a structure, the first speed control, for example, can slightly change the rate of change (the rotational acceleration) of the rotational speed Nmg of the rotary electric machine 33. The rate of change (the rotational acceleration) of the rotational speed Nmg of the rotary electric machine 33 can, for example, become smaller (lower) as the rotational speed Nmg of the rotary electric machine 33 approaches the first synchronous range. (3) In the example used to describe the embodiment, the second speed control causes the rotational speed Nmg of the rotary electric machine 33 to change such that a differential rotation is maintained within a constant range relative to the downstream synchronous speed Nsyna.However, without limiting such a structure, for example, the second speed-change control can slightly modify the differential rotation between the rotational speed Nmg of the rotary electric machine 33 and the subsequent synchronous speed Nsyna. The rotational speed Nmg of the rotary electric machine 33 can, for example, be modified such that the differential rotation between the rotational speed Nmg of the rotary electric machine 33 and the subsequent synchronous speed Nsyna gradually becomes smaller (lower). (4) In the example used to describe the embodiment, the third speed-change control causes the rotational speed Nmg of the rotary electric machine 33 to change at a constant rate of change over time. However, without limiting such a structure, for example, the third speed-change control can slightly modify the rate of change (the rotational acceleration) of the rotational speed Nmg of the rotary electric machine 33.The rate of change (rotational acceleration) of the rotational speed Nmg of the rotary electric machine 33 can, for example, decrease as the rotational speed Nmg of the rotary electric machine 33 approaches the second synchronous range. (5) In the example used to describe the embodiment, the first synchronous range is defined by a speed range (from (Neg-ΔN2) to (Neg+ΔN2)) which has upper and lower limits, each defined by the second determining differential speed ΔN2 with respect to the rotational speed Neg of the internal combustion engine EG. However, without being restrictive for such a structure, for example, at the time of upshifting, the first synchronous range can be defined by a speed range (Neg to (Neg+ΔN2)) from the rotational speed Nmg of the internal combustion engine EG up to a speed that is higher than the rotational speed Neg of the internal combustion engine EG by the second determining differential speed ΔN2.On the other hand, for example, at the time of downshifting, the first synchronous range can be defined with a speed range ((Neg-ΔN2) to Neg) from a speed that is less than the speed Neg of the internal combustion engine EG by the second determining differential speed ΔN2, up to the speed Neg of the internal combustion engine EG. The same applies to the second synchronous range. (6) In the example used to describe the embodiment, after the speed Nmg of the rotary electric machine 33 reaches the first synchronous range by executing the first speed-change control, the second speed-change control is executed first, and then the third speed-change control is executed. However, without this being a limitation for such a structure, for example, a transition from the first speed-change control directly to the third speed-change control can be executed without executing the second speed-change control.In this case, the rotational speed Nmg of the rotary electric machine 33 can change continuously at a constant rate of change after the rotational speed Nmg of the rotary electric machine 33 changes from the pre-synchronous speed Nsynb in conjunction with the progress of the switching operation, until not only the first synchronous range but also the second synchronous range is reached. (7) In the example used to describe the embodiment, the vehicle drive system 3 to be controlled has the decoupling engagement device 32, the rotary electric machine 33 and the transmission 35, which are provided in the power transmission path that connects the internal combustion engine EG to the edges W. However, without being limiting for such a structure, for example, as shown in Fig.As shown in Figure 8, the vehicle drive system to be controlled has a second decoupling engagement device 38, which is provided in the power transmission path between the rotary electric machine 33 and the transmission 35. Alternatively, for example, as shown in Figure 9, a fluid coupling 39 (a torque converter, a fluid coupling, etc.) with an engagement device 39L for direct coupling can be provided in the power transmission path between the rotary electric machine 33 and the transmission 35. (8) In the example used to describe the embodiment, the transmission 35 of the vehicle drive system 3 to be controlled is a multi-stage automatic transmission which has the planetary gear mechanism and the multiple shift engagement devices 35C.However, without being restrictive for such a structure, the transmission 35 of the vehicle drive system 3 to be controlled can be a different type of multi-stage automatic transmission, such as a dual-clutch transmission (DCT). It should be noted that, as long as there are no contradictions, the structures disclosed in one of the embodiments described above (including the preceding embodiment and the other / further embodiments) can be used or applied in combination with the structures disclosed in any further embodiment of the embodiments. Furthermore, the embodiments of the other structures disclosed in this description should be regarded in every respect as illustrative and exemplary. Therefore, various modifications falling within the scope of this disclosure may be apparent to the person skilled in the art. (Summary of the examples of implementation) To summarize the foregoing, the control device according to the present disclosure preferably has the following structures. [1] A control device (1) serves to control a vehicle propulsion system (3) in which an engagement device (32), a rotary electric machine (33) and a multi-stage automatic transmission (35) are provided in a power transmission path connecting an internal combustion engine (EG) to wheels (W), wherein, when the engagement device (32) is engaged to start the internal combustion engine (EG) during a shifting operation of the multi-stage automatic transmission (35) in a state in which a vehicle is moving with a torque of the rotary electric machine (33) and in which the engagement device (32) is in a disengaged state (disengagement state), the control device (1) causes a rotational speed (Nmg) of the rotary electric machine (33) to change according to a predetermined first change pattern,after the rotational speed (Nmg) of the rotary electric machine (33) changes from a pre-switching synchronous speed (synchronous speed before switching operation) (Nsynb) in conjunction with a progress of the switching operation, until a first synchronous range is reached which is determined on the basis of a rotational speed (Neg) of the internal combustion engine (EG), wherein the pre-switching synchronous speed (Nsynb) is the rotational speed of the rotary electric machine (33) in a switching stage which is set up before the switching operation is started. According to this structure, when the shifting operation coincides with the start-up control of the internal combustion engine, speed control of the rotary electric motor is executed according to the first change pattern after the speed of the rotary electric motor changes from the pre-sequence synchronous speed until the first synchronous range of the speed of the rotary electric motor is reached. If a difference occurs between an actual value and a setpoint value of the torque transmission capacity of the engagement device, the speed control of the rotary electric motor corrects the output torque of the rotary electric motor in accordance with the difference in order to maintain a stable rotational acceleration of an input component (hereinafter referred to simply as a "shift input component") of the multi-stage automatic transmission. Thus, good drivability is maintained. [2] The rotational speed (Nmg) of the rotary electric machine (33) in the switching stage established after the switching operation is completed is defined as a post-switching synchronous speed (synchronous speed after switching operation) (Nsyna), and after the rotational speed (Nmg) of the rotary electric machine (33) reaches the first synchronous range until the engagement device (32) reaches a direct engagement state, the control device (1) causes the rotational speed (Nmg) of the rotary electric machine (33) to change according to a second change pattern, which is defined to have a differential rotation (ΔNs) relative to the post-switching synchronous speed. According to this design, torque fluctuations caused when the engagement device reaches the direct engagement state are not transmitted to the wheels, and consequently, a shock associated with the engagement of the direct engagement state is avoided. Thus, good drivability can also be maintained from this perspective. [3] The first change pattern is a pattern that changes at a constant rate of change from the upstream synchronous speed (Nsynb) to the first synchronous range; the second change pattern is a pattern that is fixed to maintain the differential rotation (ΔNs) relative to the downstream synchronous speed (Nsyna) within a constant range; and after the engagement device (32) reaches the direct engagement state, until the speed (Nmg) of the rotary electric machine (33) reaches a second synchronous range determined on the basis of the downstream synchronous speed (Nsyna), the control device (1) causes the speed (Nmg) of the rotary electric machine (33) to change according to a third change pattern that changes at a constant rate of change in the direction of the downstream synchronous speed (Nsyna). According to this structure, the rotational acceleration of the switching input component is maintained constant after the rotational speed of the rotary electric machine changes from the pre-synchronous speed until the first synchronous range is reached. Furthermore, the rotational acceleration of the switching input component is also maintained constant after the engagement device reaches the direct engagement state until the rotational electric machine reaches the second synchronous range. This improves drivability. Moreover, if the switching operation coincides with the starting control of the internal combustion engine, the effects described above are achieved for almost the entire duration of the switching operation. It is only necessary that the control device according to the present disclosure should achieve at least one of the effects described above. COMMERCIAL APPLICABILITY The technology according to the present disclosure is applicable, for example, to a control device for controlling a vehicle drive system used in hybrid vehicles. Description of the reference symbols 1 Control Device 3 Vehicle Drive System 12 Rotary Engine Control Section 13 Engagement Control Section 31 Input Component 32 Decoupling Engagement Device (Engagement Device) 33 Rotary Engine 34 Shift Input Component 35 Transmission (Multi-Stage Automatic Transmission) 35C Shift Engagement Device 35A Coupled Engagement Device 35R Disengaged Engagement Device 36 Output Component EC Internal Combustion Engine W Wheel Neg Internal Combustion Engine Speed ​​Nmg Rotary Engine Speed ​​Nsynb PRE-SYNC RPM Nsyna POST-SYNC RPM ΔNs SLIP DIFFERENTIAL RPM (DIFFERENTIAL RPM)

Claims

Control device (1) for controlling a vehicle drive system (3) in which an engagement device (32), a rotary electric machine (33) and a multi-stage automatic transmission (35) are provided in a power transmission path connecting an internal combustion engine (EG) to wheels (W), wherein when the engagement device (32) is engaged to start the internal combustion engine (EG) during a shifting operation of the multi-stage automatic transmission (35) in a state in which a vehicle is moving with a torque of the rotary electric machine (33) and the engagement device (32) is in a disengaged state, the control device (1) causes a rotational speed (Nmg) of the rotary electric machine (33) to change according to a predetermined first change pattern after the rotational speed (Nmg) of the rotary electric machine (33) changes from a pre-shift synchronous speed (Nsynb) in conjunction with a progress of the shifting operation until a first synchronous range is reached,which is determined on the basis of a rotational speed (Neg) of the internal combustion engine (EG), wherein the pre-synchronous speed (Nsynb) is the rotational speed (Nmg) of the rotary electric machine (33) in a switching gear that is set up before the switching operation is started, the rotational speed (Nmg) of the rotary electric machine (33) in the switching gear that is set up after the switching operation is completed is defined as a post-synchronous speed (Nsyna), and after the rotational speed (Nmg) of the rotary electric machine (33) reaches the first synchronous range until an engagement instruction pressure for the engagement device (32) is equal to a predetermined direct engagement pressure and the engagement device (32) reaches a direct engagement state, the control device (1) causes the rotational speed (Nmg) of the rotary electric machine (33) to change according to a second change pattern that is set to have a differential rotation (ΔNs) relative to the post-synchronous speed (Nsyna). Control device (1) according to claim 1, wherein the first change pattern is a pattern that changes at a constant rate of change from the upstream synchronous speed (Nsynb) to the first synchronous range, the second change pattern is a pattern that is fixed to maintain the differential rotation (ΔNs) relative to the downstream synchronous speed (Nsyna) within a constant range, and after the engagement device (32) reaches the direct engagement state until the speed (Nmg) of the rotary electric machine (33) reaches a second synchronous range determined on the basis of the downstream synchronous speed (Nsyna), the control device (1) causes the speed (Nmg) of the rotary electric machine (33) to change according to a third change pattern that changes at a constant rate of change in the direction of the downstream synchronous speed (Nsyna).

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