Hybrid drive device

Abstract

Hybrid drive device (5) comprising: an input component (15) which is drive-coupled to an internal combustion engine (2); a motor (3) which is drive-coupled to the input component (15); a stepped speed change mechanism (7) capable of switching a speed of rotation of the input member (15) by changing an engagement state of frictional engagement elements (C-1, C-2, C-3, B-1, B-2); and a control device (20) which can control the engagement state of the friction engagement elements (C-1, C-2, C-3, B-1, B-2) at least during the shifting and can carry out a control such that an engine torque (Tmg) output by the engine (3) generates at least a part of an inertia moment (Ti) necessary for changing the rotation of input-related components which are drivingly coupled to the input component (15) during the shifting, wherein the control device (20) sets a setting value (Tmg-lim) to a smaller value of absolute values ​​of the power limit torque (Tmg-max, Tmg-min) of the engine (3) at times before and after shifting, the control device (20) limits the engine torque in an inertia phase to an absolute value equal to or smaller than the setting value (Tmg-lim), sets a target input speed (Nin-targ) of the input component (15) during shifting, and controls the engagement state of the friction engagement elements that control the rotational change of the input-related components in the inertia phase to generate the inertia torque (Ti) calculated from the target input speed (Nin-targ) in the input-related components, the control device (20) performs smoothing control to mitigate a change in the inertia moment (Ti) in a final period of shifting, sets smoothing torque share ratios of the motor (3) and the friction engagement elements in the smoothing control, and, based on the smoothing torque share ratios, performs control to distribute the torque to be shared by the motor (3) and the friction engagement elements in the smoothing control to the motor (3) and the friction engagement elements, in the smoothing control, the control device (20) controls the motor (3) and the engagement state of the friction engagement elements in a feedback manner on the basis of an actual rotational speed (Nm) of the input member (15) with respect to the target rotational speed (Nin-targ) and sets a feedback gain for the motor (3) and a feedback gain for the friction engagement elements in the feedback control according to the smoothing torque share ratios, and the control device (20) sets a start time (t13, t23, t33, t43) of the feedback control of the engine (3) and a start time (t12, t22, t32, t42) of the feedback control of the engagement state of the friction engagement elements according to the respective smoothing torque share ratios.

Description

TECHNICAL FIELDThe present invention relates to a hybrid drive device mounted on, for example, a vehicle, and more particularly to a hybrid drive device which is provided in a structure for switching a speed of rotation of an input member that is drivingly coupled to an internal combustion engine and a motor by using a stepped speed change mechanism and which generates at least a part of an inertia moment during switching of an engine torque.BACKGROUNDIn recent years, development has been advanced in hybrid vehicles that combine an internal combustion engine with a motor generator (hereinafter, simply referred to as "motor") as a power source. As a configuration of a hybrid drive device used in such a hybrid vehicle, there is proposed a so-called parallel hybrid drive device (single-motor stepped speed change hybrid drive device) configured to include a motor that is drivingly coupled to an input shaft (input member) that is drivingly coupled to an internal combustion engine and a stepped speed change mechanism that changes a speed of rotation of the input shaft in a stepped manner (see Patent Document 1).Patent Document 1 proposes to perform shift control in the parallel hybrid drive device having the stepped speed change mechanism to bring the rotation speed of the input shaft into agreement with a set target rotation speed while causing the motor to generate inertia torque of the input-related members (members drivingly coupled to the input shaft) required during the shift in the stepped speed change mechanism.Prior Art DocumentsPatent DocumentPatent Document 1: Japanese Patent Application Publication No. 2004-316831 (JP 2004-316831 A)DE 11 2007 003 244 T5 discloses a hybrid drive apparatus having an input member drivingly coupled to an internal combustion engine; a motor drivingly coupled to the input member; a stepped speed change mechanism capable of switching a speed of rotation of the input member by changing an engagement state of friction engagement elements; and a control device capable of controlling the engagement state of the friction engagement elements at least during the shifting and performing control such that an engine torque output from the motor generates at least a part of an inertia torque necessary for rotation change of input-related members drivingly coupled to the input member during the shifting. The control device sets a setting value to a smaller one of absolute values of the output limit torque of the engine at times before and after the shift, the control device limits the engine torque to an absolute value equal to or less than the setting value in an inertia phase, sets a target input rotational speed of the input member during the shift, and controls the engagement state of the friction engagement elements that control the rotation change of the input-related members in the inertia phase to generate the inertia torque calculated from the target input rotational speed in the input-related members.SUMMARY OF THE INVENTIONProblems to be Solved by the InventionWhile the shift control of Patent Document 1 is configured to cause the motor to generate the inertia torque during shifting, the output torque behavior of the motor changes with the rotation speed, so that the motor torque changes during shifting, causing the following problem. Dealing with the torque change using friction engagement elements in an engaged state (slipping state) produces an insufficient response, thereby causing a change in a change gradient of the input rotational speed during shifting or causing a change in the output torque with a downward gradient, although an accelerating state (in which an increase in driving force is required) is present.Hereinafter, a case of power-on downshift while the vehicle is running using the internal combustion engine will be described as an example of a conventional control based on FIG. 12. As shown in FIG. 12, when an actual shift starts at a time ta after a shift determination, a release-side friction element torque TA is decreased (the engagement state of friction engagement elements [clutches and brakes] on a release side is released to be the slip state) to increase the input rotational speed Nin (i.e., a rotational speed of the input-related members) because the shift-down is performed, and, to generate a total inertia torque of the input-related members from an engine torque Tmg, the engine torque Tmg is output at a level of a maximum engine torque Tmg-max that is a torque at the limit of the engine output.However, the engine speed increases as the input rotational speed Nin increases, so that the maximum engine torque Tmg-max (engine output limit) decreases, thereby causing the engine torque Tmg to change to an inertia torque having a downward gradient as indicated by an arrow X. This reduces an input torque Tin which is a sum of an engine torque Te and the engine torque Tmg, so that the release-side friction element torque TA changes to a downward gradient as indicated by an arrow Y. In other words, the engagement state of the friction engagement elements on the release side is further shifted to the release side, thereby reducing torque transmitted to an output side (wheel side) to generate the moment of inertia required by the input-dedicated members. This also causes a change of an output torque Tout with a downward gradient, and thus the following problem is caused. Despite the presence of the power-on downshift state in which a driver requests an increase in the driving force, the driving force tends to decrease during the shifting, thereby causing the driver to feel uncomfortable.The downward gradient of the engine torque Tmg indicated by the arrow X requires the release-side friction element torque TA to also change with the downward gradient indicated by the arrow Y in order to ensure the moment of inertia required by the input-related members. An engagement hydraulic pressure of each of the friction engagement elements on the release side is electronically controlled to cause the pressure to follow the change in the engine torque Tmg. However, a slower response of the hydraulic pressure than that of the electronic controller causes a difficulty in controlling the release side friction element torque TA with a good response. This delays the time of generating the inertia moment of the input-associated members and causes a change in the change gradient of the input rotational speed such as a delay of increasing the input rotational speed Nin as indicated by an arrow W, which causes a problem that, for example, a change in engine noise or a fluctuation of a tachometer occurs, and thus the driver has an uncomfortable feeling.While the power-on downshift has been described as an example of a conventional controller, the same problems occur in a power-off upshift, a power-on upshift, and a power-off downshift.Therefore, it is an object of the present invention to provide a hybrid drive device that generates at least a part of a moment of inertia during shifting from an engine torque and that can prevent a change in a gradient of change in an input rotational speed during shifting and can output a driving force according to a driving force request of a driver during shifting and thus can prevent an uncomfortable feeling from occurring during shifting.Means for Solving the ProblemsThe object of the invention is achieved with a hybrid drive device according to claim 1. Advantageous further developments of the invention are the subject of the dependent claims.A hybrid drive device (5) of the present invention is characterized (see, for example, FIGS. 1 to 11 ) as having:an input component (15) which is drivingly coupled to an internal combustion engine (2),a motor (3) drivingly coupled to the input member (15),a stepped speed change mechanism (7) capable of switching a speed of rotation of the input member (15) by changing an engagement state of friction engagement elements (C-1, C-2, C-3, B-1 and B-2), anda control device (20) that can control the engagement state of the friction engagement elements at least during shifting and can perform control such that a motor torque (Tmg) output from the motor (3) generates at least a part of a moment of inertia (Ti) necessary for changing rotation of input-related members (such as 2a, 10, K0, 3a and 15) drive-coupled to the input member (15) during shifting, whereinthe control device ( 20) sets a setting value (Tmg-lim) to a smaller one of absolute values of the output limit torque (Tmg-max, Tmg-min) of the engine ( 3) at times before and after the shift,the control device (20) limits the motor torque (Tmg) in an inertia phase to an absolute value equal to or less than the setting value (Tmg-lim), sets a target input rotational speed (Nin-targ) of the input member (15) during shifting, and controls the engagement state of the friction engagement elements that control the rotation change of the input-related members in the inertia phase to generate the moment of inertia (Ti) calculated from the target input rotational speed (Nin-targ) in the input-related members.Accordingly, the engine torque in the inertia phase is limited to the absolute value equal to or less than the setting value. This can prevent the engine torque from changing by a change in the output limit torque of the engine during shifting. Because the engagement state of the friction engagement elements that control the rotation change of the input-related members in the inertia phase is controlled to generate the inertia torque calculated from the target input rotational speed in the input-related members, the engagement state of the friction engagement elements that control the rotation change of the input-related members can be controlled in a stable manner to cause the rotational speed of the input member to match the target input rotational speed. This can prevent the change of the change gradient of the input rotational speed during the shifting, and thus can prevent the uncomfortable feeling from occurring during the shifting.Further, the engagement state of the friction engagement elements that control the rotation change of the input-related members, and specifically, the gradient of the change of the torque transmitted by the friction engagement elements may be set to a gradient at which the output torque to the wheels is generated according to the driver's driving force request. This enables the driving force to be output according to the driver's driving force request during shifting, thereby preventing the uncomfortable feeling from occurring during shifting.According to a preferred aspect, the hybrid drive device (5) of the present invention is characterized (see, for example, FIGS. 4, 5, 7, 9, and 11 ) in that the control device (20) performs smoothing control to alleviate a change in the inertia torque (Ti) in a final period of the shift, sets a smoothing torque sharing ratios of the engine (3) and the friction engagement elements in the smoothing control, and performs control to distribute torque to be shared by the engine (3) and the friction engagement elements in the smoothing control to the engine (3) and the friction engagement elements on the basis of the smoothing torque sharing ratios.Thus, the smoothing torque sharing ratios of the engine and the friction engagement elements are set in the smoothing control, and based on the smoothing torque sharing ratios, the control is performed to distribute the torque to be shared by the engine and the friction engagement elements in the smoothing control to the engine and the friction engagement elements. This can eliminate the need for changing the torque of the internal combustion engine in the smoothing control, and thus can prevent variation such as engine spin or input speed drop that may occur when the smoothing control is performed using the internal combustion engine. Setting the smoothing torque sharing ratios of the engine and the friction engagement elements can prevent the engine torque from being required to exceed the output limit torque of the engine, and thus can realize good smoothing control that does not require the engine and the friction engagement elements to share excessive torque.According to another preferred aspect, the hybrid drive device (5) of the present invention is characterized (see, for example, FIGS. 4, 5, 7, 9, and 11 ) in that the control device (20) sets the smoothing torque sharing ratios on the basis of the engagement state of the friction engagement elements that control the rotation change of the input-related members in the inertia phase.Thus, because the smoothing torque sharing ratios are set based on the engagement state of the friction engagement elements that control the rotation change of the input-related members in the inertia phase, the limit of torque that can be generated by the friction engagement elements can be prevented from being exceeded. Thus, good smoothing control can be realized.According to the present invention, in the smoothing control, the control device (20) controls the motor (3) and the engagement state of the friction engagement elements on the basis of an actual rotational speed (Nin) of the input member (15) with respect to the target input rotational speed (Nin-targ) in a feedback manner, and sets a feedback gain for the motor and a feedback gain for the friction engagement elements in the feedback control according to the smoothing torque sharing ratios.Thus, because the feedback gains for the motor and the friction engagement elements are set in the feedback control of the smoothing control according to the respective smoothing torque sharing ratios, hunting in the feedback control or the like can be prevented to prevent deviation of the control. Thus, good feedback control can be realized.According to the present invention, the control device ( 20) sets a start time (such as t 13, t 23, t 33, or t 43) of the feedback control of the engine ( 3) and a start time (such as t 12, t 22, t 32, or t 42) of the feedback control of the engagement state of the friction engagement elements according to the respective smoothing torque sharing ratios.Thus, because the start time of the feedback control of the engine and the start time of the feedback control of the engagement state of the friction engagement elements are set according to the respective smoothing torque sharing ratios, good feedback control can be realized in consideration of the engine control, the response of which is more rapid than the hydraulic response of the friction engagement elements, in particular.It is intended that the symbols in the brackets shown above be used for reference to the drawings. These symbols are used for convenience in understanding the invention and do not affect the nature of the claims.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic diagram showing a hybrid automobile to which the present invention can be applied. FIG. 2 is an engagement table of a stepped speed change mechanism. FIG. 3 is a flowchart showing inertia calculation control during power-on downshift. FIG. 4 is a flowchart showing smoothing control. FIG. 5 is a timing chart showing values during power-on downshift. FIG. 6 is a flowchart showing the inertia calculation control during an upshift without power demand. FIG. 7 is a timing diagram showing the values during the power-off upshift. FIG. 8 is a flowchart showing the inertia calculation control during a power-on upshift. FIG. 9 is a timing diagram showing the values during the power-on upshift. FIG. 10 is a flowchart showing the inertia calculation control during power-off non-request downshift. FIG. 11 is a timing chart showing the values during the power-off no power demand downshift. FIG. 12 is a timing chart showing the values during a conventional power-on downshift.FORMS FOR CARRYING OUT THE INVENTIONAn embodiment according to the present invention will be described below on the basis of Figs. 1 to 11. First, based on FIG. 1, a hybrid automobile (vehicle) equipped with a hybrid drive device according to the present invention will be described. This hybrid drive apparatus is preferably mounted on a front engine front drive (FF) vehicle. The right-left direction in FIG. 1 corresponds to the right-left direction in the actual state of the mounted vehicle. However, for convenience of description, the side of a drive source such as an engine is called the "front side", and the side opposite from the drive source side is called the "rear side". The term "drivingly coupled" refers to a state in which rotary members are coupled to each other so as to be able to transmit a driving force therebetween, and is used as a concept including a state in which the rotary members are coupled to rotate as a unit or a state in which the rotary members are coupled to be able to transmit the driving force via, for example, a clutch.[Schematic Structure of Hybrid Drive Apparatus]As shown in FIG. 1, a hybrid drive device 1 has, in addition to an internal combustion engine 2, a motor generator (motor) 3 as a drive source. A hybrid drive device 5 constituting a drive train of the hybrid vehicle 1 includes: a stepped speed change mechanism 7 provided in a transmission path 30 between the internal combustion engine 2 and wheels 6; a power transmission device 10 that is disposed between the stepped speed change mechanism 7 and the internal combustion engine 2 and can transmit power by drivingly coupling the internal combustion engine 2 to an input shaft (input member) 15 of the stepped speed change mechanism 7; the motor 3 that is drivingly coupled to the input shaft 15; a hydraulic control device 21 that hydraulically controls friction engagement elements (clutches and brakes) (described in detail later) of the stepped speed change mechanism 7; and a control unit (ECU) 20 that serves as a control device that can freely control the motor 3 and the internal combustion engine 2 by commands and can electronically control the hydraulic control device 21.The control unit 20 is coupled to an input shaft rotation sensor 80 that detects a rotation speed (input rotation speed Nin) of the input shaft 15, an output shaft rotation sensor (vehicle speed sensor) 81 that detects a rotation speed (output rotation speed Nout) of a counter gear 24 or a counter shaft 28 (which will be described in detail later), and an accelerator operation amount sensor 82 that detects an accelerator operation amount that is a depression amount of an accelerator pedal (not shown). The control unit 20 stores therein a recorded shift map (not shown). The control unit 20 performs shift determination by referring to the shift map on the basis of the output rotational speed Nout (i.e., the vehicle speed) and the accelerator operation amount, and performs shift control (power-on downshift, power-off upshift, power-on upshift, and power-off downshift) of the stepped speed change mechanism 7 (which will be described later in detail).The power transmission device 10 is formed of a damper 12 coupled to a crankshaft 2 aof the internal combustion engine 2 via a drive plate 11, a connection shaft 13 connected to the damper 12, and a clutch K 0 that connects and interrupts power transmission between the connection shaft 13 and the input shaft 15 of the stepped speed change mechanism 7. The clutch K 0 is configured by, for example, a multi-plate clutch, and is formed of an inner friction plate 17 drivingly coupled to the connecting shaft 13 and an outer friction plate 19 drivingly coupled to the input shaft 15. In other words, the clutch K 0 has the inner friction plate 17 drivingly coupled to a transmission path 31 on the engine side of the transmission path 30, and the outer friction plate 19 drivingly coupled to a transmission path 32 on the wheel side of the transmission path 30.Further, the motor 3 is provided on the outer diameter side of the clutch K 0 to overlap the clutch K 0 at a position in the axial direction thereof. The motor 3 is formed of a rotor 3 athat is drivingly coupled to the input shaft 15 and a stator 3 bthat is disposed on the outer side in the radial direction of the rotor 3 ato face the same.That is, when the vehicle is driven using mainly a driving force of the internal combustion engine 2, the hybrid drive device 5 uses the control unit (ECU) 20 to control the hydraulic control device 21 to engage the clutch K 0. During EV driving of driving the vehicle with only a driving force of the motor 3 drivingly coupled to the transmission path 32 on the wheel side, the hybrid drive device 5 disengages the clutch K 0 to disconnect the transmission path 31 on the engine side from the transmission path 32 on the wheel side, that is, to disconnect the internal combustion engine 2.[Structure of Stepped Speed Change Mechanism]A structure of the stepped speed change mechanism 7 will be described. The stepped speed change mechanism 7 includes a planetary gear SP and a planetary gear unit PU on the input shaft 15. the planetary gear SP includes a sun gear S 1, a carrier CR 1, and a ring gear R 1. The carrier CR1 has a pinion P1 which meshes with the sun gear S1 and the ring gear R1. Thus, the planetary gear SP is what is called a single pinion planetary gear.The planetary gear unit PU has four rotating elements of a sun gear S 2, a sun gear S 3, a carrier CR 2, and a ring gear R 2. The carrier CR2 has a long pinion PL meshing with the sun gear S2 and the ring gear R2, and a short pinion PS meshing with the sun gear S3 in such a manner that the long pinion PL and the short pinion PS mesh with each other. Thus, the planetary gear unit PU is what is called a Ravigneaux type planetary gear.The sun gear S 1 of the planetary gear SP is fixed to a housing 23. The ring gear R 1 of the planetary gear SP is drivingly coupled to the input shaft 15, and thus the rotation of the ring gear R 1 is identical to the rotation of the input shaft 15 (hereinafter, referred to as "input rotation"). The stationary sun gear S1 and the input rotation of the ring gear R1 cause a rotation to be performed at a reduced speed obtained by reducing the speed of the input rotation. The carrier CR1 is connected to a clutch C-1 and a clutch C-3.The sun gear S2 of the planetary gear unit PU is connected to a brake B-1 formed of a band brake to be fixable to the housing 23, and is connected to the clutch C-3 to be able to initiate the reduced speed rotation of the carrier CR1 via the clutch C-3. The sun gear S3 is connected to the clutch C-1 to be able to initiate rotation at a reduced speed of the carrier CR1.Further, the carrier CR 2 is connected to a clutch C- 2 to which the rotation of the input shaft 15 is introduced to be able to introduce the input rotation via the clutch C- 2, and is connected to a one-way clutch F- 1 and a brake B- 2 to be limited to be rotated in a direction relative to the housing 23 via the one-way clutch F- 1 and to be held stationary via the brake B- 2. The ring gear R 2 is connected to the countershaft gear 24, which in turn is connected to the wheels 6 via the countershaft 28 and a differential device 29.By engaging and disengaging the clutches C- 1 to C- 3, the brakes B- 1 and B- 2, and the one-way clutch F- 1 shown in the diagram of FIG. 1, the stepped speed change mechanism 7 having the above-described configuration, as shown in an engagement table of FIG. 2, achieves a first forward speed (1) to a sixth forward speed (6) and a first reverse speed (Rev). During shifting, according to the engagement table of FIG. 2, the friction engagement elements (clutches C- 1 to C- 3 and brakes B- 1 and B- 2) on a release side are released and the friction engagement elements on an engagement side are engaged.[Shift Control of Power Request Downshift]The shift control in the hybrid drive device 5 during the power-demand downshift while the vehicle is running using mainly the driving force of the internal combustion engine 2 will be described based on FIGS. 3 to 5. in FIG. 5, a period from time t 11 to time t 14 in which the input rotational speed Nin changes corresponds to a period of "inertia phase", and a period from time t 14 to time t 16 corresponds to a period of "torque phase" in which instantaneous parts are switched between the friction elements. In an end period of the switching from time t 12 to time t 16, "smoothing control" is performed to alleviate a change in inertia torque Ti.The power-on downshift refers to a down shift while the accelerator is operated, and corresponds to, for example, a shift state such as a kick-down state. In the power-on downshift, the rotational speed of the components drivingly coupled to the input shaft 15 (input-related components), that is, the components including the input shaft 15, the rotor 3 aof the engine 3, the clutch K 0, the connection shaft 13, the damper 12, the drive plate 11, the crankshaft 2 aof the internal combustion engine 2, and a clutch drum of the clutch C- 2, and the ring gear R 1 in the stepped speed change mechanism 7 that rotate at the same speed increases after the shift.During the power-on downshift, the engine 2 outputs the driving force based on the accelerator operation, and thus outputs torque to speed up the rotation of the input-related members. Therefore, by loosening the engagement state (release state) (by decreasing the transmitted torque) of the friction engagement elements on the release side (hereinafter, referred to as "release side friction elements") among the friction engagement elements (clutches C- 1 to C- 3 and brakes B- 1 and B- 2) subjected to engagement switching during shifting, a part of the engine torque Te that acts on the input-related components and that is transmitted to the wheel side is decreased. This can speed up the rotation of the components belonging to the input. Accordingly, during the power-on downshift, the control is performed in the inertia phase in which the rotation change is performed mainly by the release control of the release-side friction members.However, merely loosening the engagement state of the release-side friction members reduces the output torque (the vehicle driving force) transmitted to the wheel side, and thus may result in an uncomfortable feeling of the driver performing the accelerator operation operation. Therefore, in order to prevent the drop of the vehicle driving force, at least a part of the moment of inertia can be generated from the engine torque. However, when the engine torque Tmg changes during the inertia phase, the release-side friction element torque TA needs to be changed according to the change in the engine torque Tmg. Considering that the response of the hydraulic control of the release-side friction members is slower than the response of the electric control of the engine 3, the input rotational speed Nin may change in the inertia phase as indicated by the arrow W of FIG. 12, and this may result in the uncomfortable feeling of the driver.Therefore, in the present embodiment, the control is performed as described below to allow the engine torque Tmg to be output in a stable manner with as little change as possible during the inertia phase in which the engine torque Tmg and the release-side friction element torque TA share the inertia torque.[Inertia Calculation Control of Power Demand Downshift]Inertia calculation during the power-request downshift will be described based on FIG. 3 with reference to FIG. 5. when the control unit 20 has determined to perform the power-request downshift based on, for example, the accelerator operation amount and the vehicle speed, the control unit 20 starts inertia calculation control in the power-request downshift shown in FIG. 3 at time t 11 shown in FIG. 5 (S 11).The control unit 20 first sets a target input rotational speed Nin-targ in the inertia phase on the basis of the input rotational speed Nin before shifting, the input rotational speed Nin after shifting (a value obtained by multiplying the output rotational speed Nout [that is, the vehicle speed] by a gear ratio Gaf after shifting), and a target shift time tch from the start to the end of shifting. Specifically, here, in order to calculate the inertia torque Ti, the control unit 20 calculates a target rotation change acceleration αtarg, which is an acceleration of the target input rotational speed Nin-targ, by dividing a value obtained by subtracting the input rotational speed Nin before shifting from the input rotational speed Nin after shifting by the target shift time tch (S 12).Then, the control unit 20 multiplies the target rotation change acceleration atarg calculated above by a total amount of inertia of the input-related members (hereinafter, referred to as "input-related member inertia") Iin to calculate the inertia moment Ti to be generated based on the rotation change of the input-related members (S 13).Then, the control unit 20 sets a setting value serving as a limit of the engine torque in the inertia phase. Specifically, as shown in FIG. 5, the input rotational speed Nin, that is, a motor speed Nmg associated with the shift-down, increases, and thus, based on the output characteristic of the motor, the maximum motor torque Tmg-max and a minimum motor torque Tmg-min serving as output limits of the motor 3 (output limit torque of the motor) decrease in absolute values associated with the rotation change. For example, outputting the engine torque Tmg at the maximum engine torque Tmg-max serving as one of the output limits of the engine 3 to generate the inertia torque Ti results in a drop in the engine torque Tmg during the inertia phase (see FIG. 12 ).Therefore, based on the engine speed Nmg before shifting, which can be calculated from the gear ratio Gaf after shifting and the output rotational speed Nout, the control unit 20 sets a setting value Tmg-lim to the maximum engine torque Tmg-max after shifting (at time t 16) (i.e., the value having a smaller absolute value between values of the output limit torque of the engine at the times before and after shifting) so that the setting value Tmg-lim serves as the upper limit value of the engine torque Tmg (S 14).Since, in the present embodiment, the setting value Tmg-lim is set to the maximum engine torque Tmg-max after the shift (at time t16), the engine torque Tmg is obviously prevented from changing during the inertia phase by setting the setting value Tmg-lim to this value or below. However, from the viewpoint of generating the inertia moment Ti, the setting value Tmg-lim preferably has an absolute value as large as possible. Therefore, in the present embodiment, the setting value Tmg-lim is set to the maximum engine torque Tmg-max after the shift (at time t16).After setting the setting value Tmg-lim as described above, the control unit 20 sets the motor torque Tmg to be actually output to the smaller of the setting value Tmg-lim and the inertia torque Ti (when the inertia torque Ti is smaller than the setting value Tmg-lim, the motor torque Tmg to be actually output is set so that the motor 3 generates the entire inertia torque Ti), and outputs the motor torque Tmg thus set (S 15).Further, after setting the engine torque Tmg, the control unit 20 sets the release-side friction element torque TA to a value obtained by subtracting, from a target torque Ttarg, a smaller one of a value obtained by subtracting the engine torque Tmg from the inertia torque Ti, and 0 (zero) (as given in a mathematical expression Ttarg {-Min((Ti-Tmg) or 0)}) (when the engine 3 generates the entire inertia torque Ti, it sets the proportion of the release-side friction element torque TA to 0 because the release-side friction elements do not need to generate the inertia torque). In other words, the control unit 20 sets the torque to be shared by the release-side friction elements to a torque value that is decreased from the torque value required as the driving force to be output to the wheels, as indicated by a broken line in FIG. 5 ; that is, the control unit 20 sets the release-side friction element torque TA to share the remaining part of the inertia torque that cannot be generated by the engine torque Tmg. Then, the control unit 20 outputs a command such that the engagement pressure of the release-side friction elements with the hydraulic control device 21 is adjusted to obtain the release-side friction element torque TA (S 16). Then, the inertia calculation control is ended (S 17).After the inertia calculation control is finished as described above, the actual shifting starts at time t 11. The engine torque Tmg is output at the set value Tmg-lim to supplement a part of the moment of inertia Ti of the input-related components with the engine torque Tmg. Thus, the motor torque Tmg is output in a stable manner at a constant value without change as indicated by an arrow A from the time t11 to a time t13 at which feedback control of the motor for the smoothing control (to be described later) starts.The input torque Tin obtained by adding the engine torque Te to the motor torque Tmg is output along a value obtained by adding the setting value Tmg-lim to the target torque Ttarg. That is, the input torque Tin is controlled in a stable manner without exceeding the limits of the engine output in a range between an upper limit value obtained by adding the target torque Ttarg to the maximum engine torque Tmg-max and a lower limit value obtained by adding the target torque Ttarg to the minimum engine torque Tmg-min.The release-side friction elements are controlled to share the release-side friction element torque TA set as described above (to share the moment of inertia remaining after the subtraction of the engine torque Tmg). Thus, the release-side friction element torque TA is controlled to change with an upward gradient as indicated by an arrow B from the time t 11 to the time t 12 at which the feedback control of the friction elements for the smoothing control (to be described later) starts, and the gradient may be set according to a driving force request of the driver. Accordingly, the output torque Tout also changes with a constant upward gradient as indicated by an arrow C during a period from the time t 11 to the time t 13, which gives the driver depressing the accelerator pedal a feeling of the increasing output torque Tout and prevents the driver from having the uncomfortable feeling during shifting.Further, during the period from the time t 11 to the time t 13, the engine torque Tmg in the inertia phase during the shifting is limited to the setting value Tmg-lim that has been set to or below the smaller value between the values of the output limit torque of the engine (maximum engine torque Tmg-max) at the times before and after the shifting. This can prevent the engine torque Tmg from being changed by a change in the output limit torque of the engine (maximum engine torque Tmg-max) during the shifting (see FIG. 12 ). Consequently, the input rotational speed Nin (rotation change of the input-related members) increases in a stable manner with a constant gradient to reach the target input rotational speed Nin-targ as indicated by an arrow D. Therefore, for example, a change in engine noise and a fluctuation in a speedometer are prevented, thereby preventing the driver from having the uncomfortable feeling during shifting.[Smoothing Control of Power Request Downshift]Now, the conventional control of the smoothing control to alleviate the change in the inertia moment Ti in the final period of switching will be described based on FIG. 12. As shown in FIG. 12, in the final period of the shift from time tb to time te, the input-related members gradually stop increasing the rotation speed, that is, the rotational acceleration of the input-related members is switched in the decelerating direction. In order to delay the speed increase of the input-related components, it has been necessary to control the engine torque Tmg in the negative direction and reduce the torque of the internal combustion engine 2.However, because the torque reduction of the internal combustion engine 2 is performed by adjusting the fuel injection amount or ignition timing, for example, the engine torque Te is not easily reduced in a stable manner as in the case of engine control or hydraulic control of the friction engagement elements. Thus, there has been a problem of relatively frequent occurrence of a phenomenon such as that called engine spin in which a delayed reduction in the engine torque Te causes a temporary increase in the input rotational speed Nin as indicated by a broken line U and a phenomenon in which too early a reduction in the engine torque Te causes a temporary drop and a hold-down of the input rotational speed Nin as indicated by a broken line V.Thus, the present embodiment makes it possible to complete the smoothing control without using the internal combustion engine 2 (the engine torque Te) by controlling the motor 3 and controlling the engagement state of the release-side friction members. The smoothing control according to the present embodiment will be described below based on FIGS. 4 and 5.As described in FIG. 4, when a shift progress ratio reaches a predetermined progress ratio based on, for example, a value of a speed ratio (ratio of the input rotational speed Nin to the output rotational speed Nout), the control unit 20 starts the smoothing control (S 51) and determines whether the feedback control (FB) of the release-side friction members has started or the feedback control (FB) of the engine 3 has started so that the actual input rotational speed (actual rotational speed of the input shaft) Nin detected by the input shaft rotation sensor 80 reaches the target input rotational speed Nin (S 52).The control unit 20 waits until the feedback control of the release-side friction elements or the feedback control of the engine 3 starts (No at S 52), and when one of them has started (Yes at S 52), sets smoothing torque sharing ratios of the engine torque Tmg and the release-side friction element torque TA (i.e., sharing ratios of the torque used in the smoothing control of the engine torque and the friction element torque). Then, the control unit 20 sets respective feedback gains, that is, a feedback gain for the release-side friction elements and a feedback gain for the motor 3, according to the smoothing torque sharing ratios to distribute the torque divided in the smoothing control (S 53).Specifically, when the smoothing torque sharing ratios are set, the control unit 20 calculates a ratio of the maximum engine torque Tmg-max (or the minimum engine torque Tmg-min) to the moment of inertia Ti as the smoothing torque sharing ratio of the engine 3, and obtains the remainder (100% smoothing torque sharing ratio of the engine 3) as the smoothing torque sharing ratio of the release-side friction elements. In other words, the maximum engine torque Tmg-max (or the minimum engine torque Tmg-min) reaches the post-shift setting value Tmg-lim, and thus the ratio to the engine torque Tmg output at the setting value Tmg-lim can be calculated from the engagement state (i.e., the release-side friction element torque TA) of the release-side friction elements (friction engagement elements that control the rotation change of the input-related members) in the inertia phase, so that the smoothing torque sharing ratios can be set based on the release-side friction element torque TA.After the feedback gains for the release-side friction elements and the engine 3 are set according to the respective smoothing torque sharing ratios in this manner, the control unit 20 determines whether the shift control has ended (S 54), and if the shift control has not ended (No at S 54), it outputs feedback gain sharing ratios (S 55), that is, performs the feedback control of the release-side friction elements and the feedback control of the engine 3 with the respective sharing gains.Specifically, the control unit 20 multiplies the feedback gains for the release-side friction elements and the motor 3 set according to the respective smoothing torque sharing ratios by a deviation obtained by subtracting the input rotational speed Nin from the target input rotational speed Nin-targ to obtain a deviation for the motor and a deviation for the release-side friction elements, and calculates a motor feedback torque and a release-side friction element feedback torque by applying a proportional-integral (PI) control to the deviations for the motor and the release-side friction elements. The calculated feedback torque values are reflected in the output of the engine 3 and the hydraulic control of the release-side friction elements. Subsequently, if the control unit 20 determines that the shift control has ended at the time t 16 (Yes at S 54), the smoothing control is ended (S 56).The response of the engine 3 in the output control thereof is faster than the hydraulic response of the release side friction members. Thus, starting the feedback control at the same time may result in a delay in the response of the release-side friction elements. Therefore, as shown in FIG. 5, the feedback control of the release-side friction elements starts at time t 12, which is a start time obtained based on time t 13, which serves as the start time of the feedback control of the engine 3, while considering the amount of delay in response of the release-side friction elements and the smoothing torque sharing ratios.Accordingly, as shown in FIG. 5, increasing the release-side friction element torque TA from the time t 12 increases the torque transmitted to the wheel side to start decreasing the moment of inertia Ti to the input-related members (i.e., decrease the rotation change), and decreasing the motor torque Tmg (the input torque Tin) from the time t 13 gradually decreases the moment of inertia Ti and finally decreases it to 0. During this time, engagement-side friction elements are hydraulically controlled to start engagement at time t 14, and an engagement-side friction element torque TBis increased while the release-side friction element torque TAis decreased, that is, the torque phase in which the torque transmission is switched from the release-side friction elements to the engagement-side friction elements starts. Then, at time t 15, the engagement-side friction elements are placed in the engaged state, and further, at time t 16, releasing the release-side friction elements causes output torque Tout according to the gear ratio after shifting. At time t 16, the shift control is ended.As described above, the smoothing control sets the smoothing torque sharing ratios of the engine and the release-side friction engagement elements, and performs control to distribute, to the engine 3 and the release-side friction engagement elements, the torque to be shared therebetween in the smoothing control, based on the smoothing torque sharing ratios. This can eliminate the need for changing the torque of the internal combustion engine 2 in the smoothing control, and thus prevents a variation such as engine spin or a drop in the input rotational speed Nin that may occur when the smoothing control is performed using the internal combustion engine 2. Setting the smoothing torque sharing ratios of the engine 3 and the friction engagement elements can prevent the engine torque Tmg from being required to exceed the output limit torque of the engine 3 (the maximum engine torque Tmg-max or the minimum engine torque Tmg-min), and thus realizes good smoothing control that does not require the engine 3 and the friction engagement elements to share excessive torque.Because the smoothing torque sharing ratios are set based on the engagement state of the release-side friction members in the inertia phase, the limit of torque that can be generated by the release-side friction members can be prevented from being exceeded. Thus, good smoothing control can be realized.Because the feedback gains for the motor and the release-side friction elements are set in the feedback control of the smoothing control according to the respective smoothing torque sharing ratios, hunting in the feedback control or the like can be prevented to prevent deviation of the control. Thus, good feedback control can be realized.Because the start time of the feedback control of the engine and the start time of the feedback control of the engagement state of the friction engagement elements are set according to the respective smoothing torque sharing ratios, good feedback control can be realized in consideration of the engine control, the response of which is more rapid than the hydraulic response of the release-side friction elements, in particular.While in the present embodiment the smoothing torque sharing ratios are set based on the engagement state of the release-side friction elements in the inertia phase (i.e., the inertia torque sharing ratios of the engine torque Tmg and the release-side friction element torque TB in the inertia phase), the smoothing torque sharing ratios may be reset to new values that take into account, for example, an end time of the smoothing control. In this case as well, it is certainly preferable to set the smoothing torque sharing ratios so that the engine torque Tmg does not exceed the setting value Tmg-lim.[Shift Control of Power No Power Request Upshift]The shift control during the power-on non-upshift while the vehicle is running using mainly the driving force of the internal combustion engine 2 will be described based on FIGS. 6 and 7. In FIG. 7, a period from time t 21 to time t 24 in which the input rotational speed Nin changes corresponds to the period of the "inertia phase", and a period from time t 24 to time t 26 corresponds to the period of the "torque phase" in which the torque components are switched between the friction elements. In the end period of the switching from time t 22 to time t 26, the "smoothing control" is performed to alleviate the change in the inertia moment Ti.The power-off upshift refers to an up-shift while the accelerator is not operated, and corresponds to what is called an off-upshift state. In the power-on non-upshift, the rotation speed of the input shaft 15 (the input-related components) decreases after the shift.During the power-off non-request upshift, the internal combustion engine 2 stops outputting the driving force based on the accelerator non-operation, and thus outputs a negative torque to decelerate the rotation of the input-related members. Therefore, loosening the engagement state (release state) (reducing the transmitted torque) of the release-side friction members reduces the amount of vehicle inertia torque transmitted from the wheel side back to the engine 2, and acts on the input-related members. This may delay the rotation of the input-associated components. Accordingly, during the power-not-requested upshift, the control is performed in the inertia phase in which the rotation change is performed mainly by the release control of the release-side friction members.However, merely loosening the engagement state of the release-side friction members causes a feeling of acceleration based on a decrease in the negative torque (engine brake torque) transmitted to the wheel side and a generation of the inertia torque Ti, and thus may result in an uncomfortable feeling of the driver performing the accelerator non-operation. Therefore, in order to prevent the increase in the vehicle driving force, at least a part of the moment of inertia may be generated (or canceled) from the motor torque (negative torque or regenerative torque). However, when the engine torque Tmg changes during the inertia phase, the release-side friction element torque TA needs to be changed according to the change in the engine torque Tmg. Considering that the response of the hydraulic control of the release-side friction members is slower than the response of the electric control of the engine 3, the input rotational speed Nin may change in the inertia phase, and this may result in the uncomfortable feeling of the driver.Therefore, in the same manner as in the case of the power-demand downshift described above, the control as described below is performed to allow the engine torque Tmg to be output in a stable manner with as little change as possible during the inertia phase in which the engine torque Tmg and the release-side friction element torque TA share the inertia torque.[Inertia Calculation Control of Power No Request Upshift]The inertia calculation during the power-no-request upshift will be described based on FIG. 6 with reference to FIG. 7. When the control unit 20 has determined to perform the power-not-requested upshift based on, for example, the accelerator operation amount and the vehicle speed, the control unit 20 starts the inertia calculation control in the power-not-requested upshift shown in FIG. 6 at the time t 21 shown in FIG. 7 (S 21).In the same manner as in the case of steps S 12 and S 13 in the power-on downshift, the control unit 20 first sets the target input rotational speed Nin-targ, and calculates the target rotation change acceleration αtarg, which is the acceleration of the target input rotational speed Nin-targ, by dividing a value obtained by subtracting the input rotational speed Nin before the shifting from the input rotational speed Nin after the shifting by the target shifting time tch (S 22). Then, the control unit 20 multiplies the calculated target rotation change acceleration atarg by the input-related component inertia Iin to calculate the inertia torque Ti to be generated based on the rotation change of the input-related components (S 23).In the power-not-demanded upshift, as shown in FIG. 7, the input rotational speed Nin, that is, the engine speed Nmg, decreases in association with the upshift and reaches a lower speed after the shift, and thus, based on the performance characteristics of the engine, the maximum engine torque Tmg-max and the minimum engine torque Tmg-min serving as the performance limits of the engine 3 increase in their absolute values in association with the rotation change. For example, outputting the engine torque Tmg at the minimum engine torque Tmg-min serving as one of the output limits of the engine 3 to generate the inertia torque Ti results in an increase in the engine torque Tmg during the inertia phase.Therefore, on the basis of the engine speed Nmg before shifting, which can be calculated from a gear ratio Gbe before shifting and the output rotational speed Nout, the control unit 20 sets the setting value Tmg-lim to the minimum engine torque Tmg-min before shifting (at time t 21) (i.e., the value having a smaller absolute value between values of the power limit torque of the engine at the times before and after shifting) so that the setting value Tmg-lim serves as the lower limit value of the engine torque Tmg (S 24).While in the present embodiment the setting value Tmg-lim is set to the minimum engine torque Tmg-min before shifting (at time t 21), it is obviously prevented that the engine torque Tmg changes during the inertia phase by setting the setting value Tmg-lim to a value having an absolute value of this value or less. However, from the viewpoint of generating the inertia moment Ti, the setting value Tmg-lim preferably has an absolute value as large as possible. Therefore, in the present embodiment, the setting value Tmg-lim is set to the minimum engine torque Tmg-min before the shift (at time t21).After setting the setting value Tmg-lim in this manner, the control unit 20 sets the motor torque Tmg to be actually output to the greater one of the setting value Tmg-lim and the moment of inertia Ti (one having a smaller absolute value) (when the moment of inertia Ti is greater than the setting value Tmg-lim, sets the motor torque Tmg to be actually output such that the motor 3 generates the entire moment of inertia Ti), and outputs the motor torque Tmg thus set (S 25).Further, after setting the engine torque Tmg, the control unit 20 sets the release-side friction element torque TA to a value obtained by subtracting, from the target torque Ttarg, a smaller one of a value obtained by subtracting the engine torque Tmg from the inertia torque Ti and 0 (zero) (as given in the mathematical expression Ttarg {-Min((Ti-Tmg) or 0)}) (when the engine 3 generates the entire inertia torque Ti, sets the proportion of the release-side friction element torque TA to 0 because the release-side friction elements do not need to generate the inertia torque). In other words, the control unit 20 sets the torque to be shared by the release-side friction members to a torque value that is decreased from the torque value required as the driving force to be output to the wheels as indicated by a broken line in FIG. 7 ; that is, the control unit 20 sets the release-side friction member torque TA to share the remaining part of the inertia torque that cannot be generated by the engine torque Tmg. Then, the control unit 20 outputs a command such that the engagement pressure of the release-side friction elements with the hydraulic control device 21 is adjusted to obtain the release-side friction element torque TA (S 26). Then, the inertia calculation control is ended (S 27).After the inertia calculation control is finished as described above, the actual shifting starts at time t 21. The engine torque Tmg is output at the set value Tmg-lim to supplement a part of the moment of inertia Ti of the input-related components with the engine torque Tmg. Thus, the motor torque Tmg is output in a stable manner at a constant value without a change as indicated by an arrow E from the time t21 to a time t23 at which feedback control of the motor for the smoothing control (to be described later) starts.Accordingly, the input torque Tin obtained by adding the engine torque Te to the motor torque Tmg is output along a value obtained by adding the setting value Tmg-lim to the target torque Ttarg. That is, the input torque Tin is controlled in a stable manner without exceeding the limits of the engine output in a range between an upper limit value obtained by adding the target torque Ttarg to the minimum engine torque Tmg-min and a lower limit value obtained by adding the target torque Ttarg to the minimum engine torque Tmg-min.The release-side friction elements are controlled to share the release-side friction element torque TA set as described above (to share the moment of inertia remaining after the subtraction of the engine torque Tmg). Thus, the release-side friction element torque TA is controlled to change with an upward gradient as indicated by an arrow F from the time t 21 to the time t 22 at which the feedback control of the friction elements for the smoothing control (to be described later) starts. Accordingly, the output torque Tout changes with a downward gradient as indicated by an arrow G during a period from the time t 21 to the time t 24, which gives the driver releasing (turning off) the accelerator pedal a feeling of falling of the output torque Tout, thereby preventing the driver from having the uncomfortable feeling during the shifting.Further, during the period from the time t 21 to the time t 23, the engine torque Tmg in the inertia phase during shifting is limited to the setting value Tmg-lim that has been set to or below a value having a smaller absolute value between values of the output limit torque of the engine (minimum engine torque Tmg-min) at the times before shifting. This can prevent the engine torque Tmg from being changed by a change in the output limit torque of the engine (minimum engine torque Tmg-min) during the shifting. Consequently, the input rotational speed Nin (rotation change of the input-related members) decreases in a stable manner with a substantially constant gradient to reach the target input rotational speed Nin-targ as indicated by an arrow H. Therefore, for example, the change in engine noise and the fluctuation of the speedometer are prevented, thereby preventing the driver from feeling uncomfortable during shifting.[Smoothing Control of Power No Power Request Upshift]The smoothing control in the power-not-requested upshift will be described.The smoothing control shown in FIG. 4 is also performed in the power-no-request upshift. Specifically, when the shift progress ratio reaches the predetermined progress ratio, the control unit 20 starts the smoothing control (S 51), and determines whether the feedback control (FB) of the release-side friction members has started or the feedback control (FB) of the motor 3 has started (S 52). When the feedback control has started from one of them (Yes at S 52), the control unit 20 sets the smoothing torque sharing ratios of the engine torque Tmg and the release-side friction element torque TA, and sets the respective feedback gains, that is, the feedback gain for the release-side friction elements and the feedback gain for the engine 3, according to the smoothing torque sharing ratios to distribute the torque divided in the smoothing control (S 53).The control unit 20 sets the smoothing torque sharing ratios by calculating the ratio of the maximum engine torque Tmg-max (or the minimum engine torque Tmg-min) to the moment of inertia Ti as the smoothing torque sharing ratio of the engine 3 and obtaining the remainder (100% smoothing torque sharing ratio of the engine 3) as the smoothing torque sharing ratio of the release-side friction elements.After the feedback gains for the release-side friction elements and the engine 3 are set according to the respective smoothing torque sharing ratios in this manner, the control unit 20 determines whether the shift control has ended (S 54), and if the shift control has not ended (No at S 54), it outputs the feedback gain sharing ratios (S 55), that is, executes the feedback control of the release-side friction elements and the feedback control of the engine 3 with the respective sharing gains. If the control unit 20 determines that the control has ended at time t 26 (Yes at S 54), the smoothing control is ended (S 56).In the same manner as described above, the response of the engine 3 in the output control thereof is faster than the hydraulic response of the release-side friction members. Thus, starting the feedback control at the same time may result in a delay in the response of the release-side friction elements. Therefore, as shown in FIG. 7, the feedback control of the release-side friction elements starts at time t 22, which is a start time obtained based on time t 23 serving as the start time of the feedback control of the engine 3, while considering the amount of delay in response of the release-side friction elements and the smoothing torque sharing ratios.Accordingly, as shown in FIG. 7, increasing the release-side friction element torque TA from the time t 22 to the torque transmitted to the wheel side to start decreasing the moment of inertia Ti to the input-related members (i.e., decrease the rotation change), and increasing (decreasing the absolute value) the motor torque Tmg (the input torque Tin) from the time t 23 gradually increases the moment of inertia Ti and finally decreases it to 0. During this time, the engagement-side friction elements are hydraulically controlled to start engagement at time t24, and the engagement-side friction element torque TB is increased while the release-side friction element torque TA is decreased, that is, the torque phase in which the torque transmission is switched from the release-side friction elements to the engagement-side friction elements starts. Then, the engagement-side friction members are placed in the engaged state at time t25, and further, release of the release-side friction members causes output torque Tout according to the gear ratio after shifting at time t26. At time t 26, the shift control is ended.As described above, the smoothing control of the power-no-request upshift also sets the smoothing torque sharing ratios of the engine 3 and the release-side friction engagement elements, and performs control to distribute, to the engine 3 and the release-side friction engagement elements, the torque to be shared therebetween in the smoothing control, based on the smoothing torque sharing ratios. This can eliminate the need for changing the torque of the internal combustion engine 2 in the smoothing control, and thus prevents the fluctuation such as the engine spin or the drop in the input rotational speed Nin that may occur when the smoothing control is performed using the internal combustion engine. Setting the smoothing torque sharing ratios of the engine 3 and the friction engagement elements can prevent the engine torque Tmg from being required to exceed the output limit torque of the engine 3 (the maximum engine torque Tmg-max or the minimum engine torque Tmg-min), and thus realizes good smoothing control that does not require the engine 3 and the friction engagement elements to share excessive torque.Because the smoothing torque sharing ratios are set based on the engagement state of the release-side friction members in the inertia phase, the limit of torque that can be generated by the release-side friction members can be prevented from being exceeded. Thus, good smoothing control can be realized.Because the feedback gains for the motor and the release-side friction elements are set in the feedback control of the smoothing control according to the respective smoothing torque sharing ratios, hunting in the feedback control or the like can be prevented to prevent deviation of the control. Thus, good feedback control can be realized.Because the start time of the feedback control of the engine and the start time of the feedback control of the engagement state of the friction engagement elements are set according to the respective smoothing torque sharing ratios, good feedback control can be realized in consideration of the engine control, the response of which is more rapid than the hydraulic response of the release-side friction elements, in particular.[Shift Control of Power Request Upshift]The shift control during the power-demand upshift while the vehicle is running using mainly the driving force of the internal combustion engine 2 will be described based on FIGS. 8 and 9. In FIG. 9, a period from time t 31 to time t 32 corresponds to the period of the "torque phase" in which the torque components are switched between the friction elements, and a period from time t 32 to time t 36 in which the input rotational speed Nin changes corresponds to the period of the "inertia phase". In the end period of the switching from time t 33 to time t 36, the "smoothing control" is performed to alleviate the change in the inertia moment Ti.The power-on upshift refers to an upward shift while the accelerator pedal is operated, in other words, a state of the upshift during acceleration. In the power-on upshift, the rotation speed of the input shaft 15 (input-related components) decreases after the shift.During the power-on upshift, the internal combustion engine 2 outputs the driving force based on the accelerator operation, and thus outputs a positive torque to speed up the rotation of the input-related members. Releasing the release-side friction elements only accelerates the rotation of the components belonging to the input. Therefore, by making the engaged state (increase the transmitted torque) of the engagement-side friction members stronger, a larger amount of vehicle inertia torque is transmitted from the wheel side back to the internal combustion engine 2 and acts on the input-related members. This may delay the rotation of the input-associated components. Accordingly, in the power-on upshift, the control is performed first in the torque phase in which the torque components are switched between the release-side friction elements and the engagement-side friction elements, and then in the inertia phase in which the rotation change is performed mainly by the engagement control of the engagement-side friction elements.In the inertia phase of decreasing the rotational speed of the input-related members, the use of only the rotation control of the input-related members performed by the engagement-side friction members applies a large load to the input-side friction members. Therefore, the torque reduction of the engine 2 is also used to reduce the rotational speed of the input-related components.Further, the use of only the torque reduction of the internal combustion engine 2 can apply a large load to the input-side friction members in the inertia phase. Therefore, in order to reduce the load of the engagement-side friction members, at least a part of the moment of inertia may be generated (or canceled) from the motor torque (negative torque or regenerative torque). However, when the engine torque Tmg changes during the inertia phase, the engagement-side friction element torque TB needs to be changed according to the change in the engine torque Tmg. Considering that the response of the hydraulic control of the engagement-side friction members is slower than the response of the electric control of the engine 3, the input rotational speed Nin may change in the inertia phase, and this may result in the uncomfortable feeling of the driver.Therefore, in the same manner as in the above-described cases of the power-on downshift and the power-off upshift, the control is performed as described below to allow the engine torque Tmg to be output in a stable manner with as little change as possible during the inertia phase in which the engine torque Te (the torque being decreased), the engine torque Tmg, and the engagement-side friction element torque TB share the inertia torque.[Inertia Calculation Control of Power Request Upshift]The inertia calculation during the power-demand upshift will be described based on FIG. 8 with reference to FIG. 9. When the control unit 20 has determined to perform the power-request upshift based on, for example, the accelerator operation amount and the vehicle speed, the control unit 20 starts the inertia calculation control in the power-request upshift shown in FIG. 8 at the time t 31 shown in FIG. 9 (S 31).In the same manner as in the case of steps S 12 and S 13 in the power-on downshift, the control unit 20 first sets the target rotation speed Nin-targ, and calculates the target rotation change acceleration αtarg, which is the acceleration of the target input rotation speed Nin-targ, by dividing a value obtained by subtracting the input rotation speed Nin before the shifting from the input rotation speed Nin after the shifting by the target shifting time tch (S 32). Then, the control unit 20 multiplies the calculated target rotation change acceleration atarg by the input-related component inertia Iin to calculate the inertia torque Ti to be generated based on the rotation change of the input-related components (S 33).In the power-on upshift, as shown in FIG. 9, the input rotational speed Nin, that is, the engine speed Nmg, decreases in association with the upshift and reaches a lower speed after the shift, and thus, based on the performance characteristics of the engine, the maximum engine torque Tmg-max and the minimum engine torque Tmg-min serving as the performance limits of the engine 3 increase in absolute values in association with the rotation change. For example, outputting the engine torque Tmg at the minimum engine torque Tmg-min serving as one of the output limits of the engine 3 to generate the inertia torque Ti results in an increase in the engine torque Tmg during the inertia phase.Therefore, based on the engine speed Nmg after shifting, which can be calculated from the gear ratio Gbe before shifting and the output rotational speed Nout, the control unit 20 sets the setting value Tmg-lim to the minimum engine torque Tmg-min before shifting (at time t 31) (or alternatively, at time 32 before the start of the inertia phase) (that is, the value having a smaller absolute value between the values of the output limit torque of the engine at the times before and after shifting), so that the setting value Tmg-lim serves as the lower limit value of the engine torque Tmg (S 34).While in the present embodiment the setting value Tmg-lim is set to the minimum engine torque Tmg-min before shifting (at time t 31), it is obviously prevented that the engine torque Tmg changes during the inertia phase by setting the setting value Tmg-lim to a value having an absolute value of this value or less. However, from the viewpoint of generating the inertia moment Ti, the setting value Tmg-lim preferably has an absolute value as large as possible. Therefore, in the present embodiment, the setting value Tmg-lim is set to the minimum engine torque Tmg-min before the shift (at time t31).After setting the setting value Tmg-lim in this manner, the control unit 20 sets the motor torque Tmg to be actually output to the greater one of the setting value Tmg-lim and the inertia torque Ti (one having a smaller absolute value) (when the inertia torque Ti is greater than the setting value Tmg-lim, sets the motor torque Tmg to be actually output such that the motor 3 generates the entire inertia torque Ti), and outputs the motor torque Tmg thus set (S 35).Further, after setting the engine torque Tmg, the control unit 20 sets the engine torque Te to be decreased by a maximum torque decrease amount (such as 50%) predetermined based on the engine power, and then sets the engagement-side friction element torque TB to a value obtained by subtracting, from the target torque Ttarg, a smaller one of a value obtained by subtracting the engine torque Tmg and the engine torque Te from the inertia torque Ti and 0 (zero) (as given in a mathematical expression Ttarg {-Min((Ti-Tmg-Te) or 0)}) (when the engine 3 generates the entire inertia torque Ti, It sets the ratio of the engagement-side friction element torque TB to 0 because the engagement-side friction elements do not need to generate the inertia torque.In other words, the control unit 20 sets the torque to be shared by the engagement-side friction elements to a torque value obtained by adding an amount indicated by an arrow M to a torque value to be transmitted as the driving force to the wheels as indicated by a broken line in FIG. 9 ; that is, the control unit 20 sets the engagement-side friction element torque TBto share the remaining part of the inertia torque that cannot be generated from the engine torque Tmg and the engine torque Te. Then, the control unit 20 outputs a command such that the engagement pressure of the engagement-side friction element with the hydraulic control device 21 is adjusted to obtain the engagement-side friction element torque TB (S 36). Then, the inertia calculation control is ended (S 37).After the inertia calculation control is finished as described above, the actual shifting starts at time t 31. First, the release-side friction element torque TA is decreased with a predetermined gradient, while the engagement-side friction element torque TB is increased with a predetermined gradient to switch the torque ratio from the release-side friction elements to the engagement-side friction elements (torque phase). Then, in order to supplement the moment of inertia Ti of the input-related components with the engine torque Te and the engine torque Tmg, the engine torque Tmg is output at the set value Tmg-lim, and the engine torque Te is decreased as described above. Thus, the motor torque Tmg is output in a stable manner with a constant value without a change as indicated by an arrow I from the time t32 to a time t34 at which feedback control of the motor for the smoothing control (to be described later) starts.Accordingly, the input torque Tin obtained by adding the engine torque Te to the engine torque Tmg is output along a value obtained by adding the amount of engine torque reduction and the setting value Tmg-lim to the target torque Ttarg. That is, the input torque Tin is controlled in a stable manner without exceeding the limits of the engine output. The engine torque Te is decreased to be substantially constant in a stable manner.The engagement-side friction elements are controlled to share the engagement-side friction element torque TBwhich is set as described above (to share the moment of inertia which remains after subtraction of the engine torque Tmgand the engine torque Te). Thus, the engagement-side friction element torque TB is controlled to follow a constant gradient as indicated by an arrow J from the time t 32 to the time t 33 at which the feedback control of the friction elements for the smoothing control (which will be described later) starts. Accordingly, the output torque Tout follows a substantially constant gradient as indicated by an arrow K during a period from the time t 32 to the time t 34, which prevents the driver depressing the accelerator pedal from feeling a feeling of decrease in the output torque Tout (feeling of deceleration), thereby preventing the driver from feeling uncomfortable during shifting.Further, during the period from time t 32 to time t 34, the engine torque Tmg in the inertia phase during shifting is limited to the setting value Tmg-lim that has been set to or below a value having a smaller absolute value between values of the output limit torque of the engine (minimum engine torque Tmg-min) at the times before shifting. This can prevent the engine torque Tmg from being changed by a change in the output limit torque of the engine (minimum engine torque Tmg-min) during the shifting. Consequently, the input rotational speed Nin (rotation change of the input-related members) decreases in a stable manner with a constant gradient to reach the target input rotational speed Nin-targ as shown by an arrow L. Therefore, for example, the change in engine noise and the fluctuation of the speedometer are prevented, thereby preventing the driver from feeling uncomfortable during shifting.[Smoothing Control of Power Request Upshift]The smoothing control in the power-demand upshift will be described. The smoothing control shown in FIG. 4 is also performed in the power-demand upshift. Specifically, when the shift progress ratio reaches the predetermined progress ratio, the control unit 20 starts the smoothing control (S 51), and determines whether the feedback control (FB) of the engagement-side friction members has started or the feedback control (FB) of the motor 3 has started (S 52). When the feedback control has started from one of them (Yes at S 52), the control unit 20 sets the smoothing torque sharing ratios of the motor torque Tmg and the engine-side friction element torque TB, and sets the respective feedback gains, that is, the feedback gain for the engagement-side friction elements and the feedback gain for the motor 3, according to the smoothing torque sharing ratios to distribute the torque divided in the smoothing control (S 53).While the engine torque Te is decreased during the inertia phase in the power-demand upshift, the smoothing control is characterized in that the smoothing torque sharing ratios of the engine torque Tmg and the engagement-side friction element torque Tb are set without including the engine torque Te.The control unit 20 sets the smoothing torque sharing ratios by calculating the ratio of the maximum engine torque Tmg-max (or the minimum engine torque Tmg-min) to the moment of inertia Ti as the smoothing torque sharing ratio of the engine 3 and obtaining the remainder (100% smoothing torque sharing ratio of the engine 3) as the smoothing torque sharing ratio of the engagement-side friction elements.After the feedback gains for the engagement-side friction elements and the engine 3 are set according to the respective smoothing torque sharing ratios in this manner, the control unit 20 determines whether the shift control has ended (S 54), and if the shift control has not ended (No at S 54), it outputs the feedback gain sharing ratios (S 55), that is, performs the feedback control of the engagement-side friction elements and the feedback control of the engine with the respective sharing gains. If the control unit 20 determines that the shift control has ended at time t 36 (Yes at S 54), the smoothing control is ended (S 56).In the same manner as described above, the response of the motor 3 in the output control thereof is faster than the hydraulic response of the engagement-side friction members. Thus, starting the feedback control at the same time may result in a delay in the response of the engagement-side friction elements. Therefore, as shown in FIG. 9, the feedback control of the engagement-side friction elements starts at time t 33, which is a start time obtained based on time t 34 serving as the start time of the feedback control of the engine 3, while considering the amount of delay in the response of the engagement-side friction elements and the smoothing torque sharing ratios.Accordingly, as shown in FIG. 9, decreasing the engagement-side friction element torque TBfrom the time t 33 to the torque transmitted to the wheel side to start decreasing the moment of inertia Tito the input-related members (i.e., decrease the rotation change), and increasing (decreasing the absolute value) the motor torque Tmg(input torque Tin) from the time t 34 gradually decreases the moment of inertia Tiand finally decreases it to zero. At time t 35, the engagement state is established in which the engagement-side friction element torque TB serves as the torque transmitted to the wheel side, and the inertia phase is substantially finished. Accordingly, the engagement of the engagement side friction elements is completed (full engagement) at time t 36, and the shift control is ended at time t 36.As described above, the smoothing control of the power-demand upshift also sets the smoothing torque sharing ratios of the engine 3 and the engagement-side friction elements, and, based on the smoothing torque sharing ratios, performs control to distribute, to the engine 3 and the engagement-side friction elements, the torque shared therebetween in the smoothing control. This can eliminate the need for changing the torque of the internal combustion engine 2 in the smoothing control, and thus prevents the fluctuation such as the engine spin or the drop in the input rotational speed Nin that may occur when the smoothing control is performed using the internal combustion engine 2. Setting the smoothing torque sharing ratios of the engine 3 and the friction engagement elements can prevent the engine torque Tmg from being required to exceed the output limit torque of the engine 3 (the maximum engine torque Tmg-max or the minimum engine torque Tmg-min), and thus realizes good smoothing control that does not require the engine 3 and the friction engagement elements to share excessive torque.Because the smoothing torque sharing ratios are set based on the engagement state of the engagement-side friction elements in the inertia phase, the limit of torque that can be generated by the engagement-side friction elements can be prevented from being exceeded. Thus, good smoothing control can be realized.Because the feedback gains for the motor and the engagement-side friction elements are set in the feedback control of the smoothing control according to the respective smoothing torque sharing ratios, hunting in the feedback control or the like can be prevented to prevent deviation of the control. Thus, good feedback control can be realized.Because the start time of the feedback control of the engine and the start time of the feedback control of the engagement state of the friction engagement elements are set according to the respective smoothing torque sharing ratios, good feedback control can be realized in consideration of the engine control, the response of which is more rapid than the hydraulic response of the engagement-side friction elements, in particular.[Shift Control of Power No Power Request Downshift]The shift control during the power-off non-request downshift while the vehicle is running using mainly the driving force of the internal combustion engine 2 will be described based on FIGS. 10 and 11. In FIG. 11, a period from time t 41 to time t 42 corresponds to the "torque phase" in which the torque components are switched between the friction elements, and a period from time t 42 to time t 46 in which the input rotational speed Nin changes corresponds to the period of the "inertia phase". In the end period of the switching from time t 43 to time t 46, the "smoothing control" is performed to alleviate the change in the inertia moment Ti.The power-off non-request downshift refers to a down shift while the accelerator is not operated, in other words, a state of the downshift during deceleration. In the power-not-requested downshift, the rotation speed of the input shaft 15 (input-related components) increases after the shift.During the power-off non-request downshift, the engine 2 stops outputting the driving force based on the accelerator non-operation, and thus outputs a negative torque to retard the rotation of the input-related members. Releasing the release-side friction elements merely decelerates the rotation of the components belonging to the input. Therefore, by enhancing the engaged state (increasing the transmitted torque) of the engagement-side friction members, a larger amount of vehicle inertia torque is transmitted from the wheel side back to the engine 2 and acts on the input-related components. This can speed up the rotation of the components belonging to the input. Accordingly, in the power-not-requested downshift, the control is performed first in the torque phase in which the torque components are switched between the release-side friction elements and the engagement-side friction elements, and then in the inertia phase in which the rotation change is performed mainly by the engagement control of the engagement-side friction elements.The use of only the acceleration of the components belonging to the input can apply a large load to the input-side friction elements in the inertia phase. Therefore, in order to reduce the load of the engagement-side friction members, at least a part of the moment of inertia can be generated from the engine torque (positive torque). However, when the engine torque Tmg changes during the inertia phase, the engagement-side friction element torque TB needs to be changed according to the change in the engine torque Tmg. Considering that the response of the hydraulic control of the engagement-side friction members is slower than the response of the electric control of the engine 3, the input rotational speed Nin may change in the inertia phase, and this may result in the uncomfortable feeling of the driver.Therefore, in the same manner as in the above-described cases of the power-demand downshift, the power-no upshift, and the power-demand upshift, the control is performed as described below to allow the engine torque Tmg to be output in a stable manner with as little change as possible during the inertia phase in which the engine torque Tmg and the engagement-side friction element torque TB share the inertia torque.[Inertia Calculation Control of Power No Power Request Downshift]The inertia calculation during the power-not-requested downshift will be described based on FIG. 10 with reference to FIG. 11. When the control unit 20 has determined to perform the power-non-request downshift based on, for example, the accelerator operation amount and the vehicle speed, the control unit 20 starts the inertia calculation control in the power-non-request downshift shown in FIG. 10 at the time t 41 shown in FIG. 11 (S 41).In the same manner as in the case of steps S 12 and S 13 in the power-on downshift, the control unit 20 first sets the target input rotational speed Nin-targ, and calculates the target rotation change acceleration αtarg, which is the acceleration of the target input rotational speed Nin-targ, by dividing a value obtained by subtracting the input rotational speed Nin before the shifting from the input rotational speed Nin after the shifting by the target shifting time tch (S 42). Then, the control unit 20 multiplies the calculated target rotation change acceleration atarg by the input-related component inertia Iin to calculate the inertia torque Ti to be generated based on the rotation change of the input-related components (S 43).In the power-not-requested downshift, as shown in FIG. 11, the input rotational speed Nin, that is, the engine speed Nmg, increases in association with the downshift and reaches a higher speed after the shift, and thus, based on the performance characteristics of the engine, the maximum engine torque Tmg-max and the minimum engine torque Tmg-min serving as the performance limits of the engine 3 decrease in absolute values in association with the rotation change. For example, outputting the engine torque Tmg at the maximum engine torque Tmg-max serving as one of the output limits of the engine 3 to generate the inertia torque Ti results in a decrease in the engine torque Tmg during the inertia phase.Therefore, based on the engine speed Nmg after the shift that can be calculated from the gear ratio Gbe before the shift and the output rotational speed Nout, the control unit 20 sets the setting value Tmg-lim to the maximum engine torque Tmg-max after the shift (at the time t 46) (that is, the value having the smaller absolute value between values of the power limit torque of the engine at the times before and after the shift) so that the setting value Tmg-lim serves as the upper limit value of the engine torque Tmg (S 44).While in the present embodiment the setting value Tmg-lim is set to the maximum motor torque Tmg-max after the shift (at time t 46), it is obviously prevented that the motor torque Tmg changes during the inertia phase by setting the setting value Tmg-lim to a value having an absolute value of this value or less. However, from the viewpoint of generating the inertia moment Ti, the setting value Tmg-lim preferably has an absolute value as large as possible. Therefore, in the present embodiment, the setting value Tmg-lim is set to the maximum engine torque Tmg-max after the shift (at time t46).After setting the setting value Tmg-lim in this manner, the control unit 20 sets the motor torque Tmg to be actually output to the smaller of the setting value Tmg-lim and the inertia moment Ti (when the inertia moment Ti is smaller than the setting value Tmg-lim, sets the motor torque Tmg to be actually output so that the motor 3 generates the entire inertia moment Ti), and outputs the motor torque Tmg thus set (S 45).Further, after setting the engine torque Tmg, the control unit 20 sets the engagement-side friction element torque TB to a value obtained by subtracting, from the target torque Ttarg, a smaller one of a value obtained by subtracting the engine torque Tmg from the inertia torque Ti and 0 (zero) (as given in the mathematical expression Ttarg {-Min((Ti-Tmg) or 0)}) (when the engine 3 generates the entire inertia torque Ti, it sets the proportion of the engagement-side friction element torque TB to 0 because the engagement-side friction elements do not need to generate the inertia torque). In other words, the control unit 20 sets the torque to be shared by the engagement-side friction members to a torque value obtained by adding an amount indicated by an arrow R to a torque value to be transmitted as the driving force to the wheels as indicated by a broken line in FIG. 11 ; that is, the control unit 20 sets the engagement-side friction member torque TBto share the remaining part of the inertia torque that cannot be generated by the engine torque Tmg. Then, the control unit 20 outputs a command such that the engagement pressure of the engagement-side friction elements with the hydraulic control device 21 is adjusted to obtain the engagement-side friction element torque TB (46). Then, the inertia calculation control is ended (S 47).After the inertia calculation control is finished as described above, the actual shifting starts at time t 41. First, the release-side friction element torque TA is decreased with a predetermined gradient, while the engagement-side friction element torque TB is increased with a predetermined gradient to switch the torque ratio from the release-side friction elements to the engagement-side friction elements (torque phase). Then, in order to supplement the moment of inertia Ti of the input-related components with the motor torque Tmg, the motor torque Tmg is output at the set value Tmg-lim. Thus, the motor torque Tmg is output in a stable manner with a constant value without a change as indicated by an arrow N from the time t42 to a time t44 at which feedback control of the motor for the smoothing control (to be described later) starts.Accordingly, the input torque Tin obtained by adding the engine torque Te to the motor torque Tmg is output along a value obtained by adding the engine torque decrease amount and the setting value Tmg-lim to the target torque Ttarg. That is, the input torque Tin is controlled in a stable manner without exceeding the limits of the engine output.The engagement-side friction elements are controlled to share the engagement-side friction element torque TB festgelegt as described above (to share the moment of inertia remaining after the subtraction of the motor torque Tmg). Thus, the engagement-side friction element torque TB is controlled to follow a constant gradient as indicated by an arrow O from the time t 42 to the time t 43 at which the feedback control of the friction elements for the smoothing control (which will be described later) starts. Accordingly, the output torque Tout follows a substantially constant gradient as indicated by an arrow P during a period from the time t 42 to the time t 44 and prevents the driver releasing (not operating) the accelerator pedal from feeling a feeling of increase in the output torque (Tout) (feeling of acceleration), thereby preventing the driver from feeling the uncomfortable feeling during shifting.Further, during the period from the time t 42 to the time t 44, the engine torque Tmg in the inertia phase during the shifting is limited to the setting value Tmg-lim that has been set to or below a value having a smaller absolute value between values of the output limit torque of the engine (maximum engine torque Tmg-max) at the times before the shifting. This can prevent the engine torque Tmg from being changed by a change in the output limit torque of the engine (maximum engine torque Tmg-max) during the shifting. Consequently, the input rotational speed Nin (rotation change of the input-related members) decreases in a stable manner with a constant gradient to reach the target input rotational speed Nin-targ as indicated by an arrow Q. Therefore, for example, the change in engine noise and the fluctuation at the speedometer are prevented, thereby preventing the driver from having the uncomfortable feeling during shifting.[Smoothing Control of Power No Power Request Downshift]The smoothing control in the power-not-requested downshift will be described. The smoothing control shown in FIG. 4 is also performed in the power-no-request downshift. Specifically, when the shift progress ratio reaches the predetermined progress ratio, the control unit 20 starts the smoothing control (S 51), and determines whether the feedback control (FB) of the engagement-side friction members has started or the feedback control (FB) of the motor 3 has started (S 52). When the feedback control has started from one of them (Yes at S 52), the control unit 20 sets the smoothing torque sharing ratios of the motor torque Tmg and the engagement-side friction element torque TB, and sets, according to the smoothing torque sharing ratios, the respective feedback gains, that is, the feedback gain for the engagement-side friction elements and the feedback gain for the motor 3 to distribute the torque shared in the smoothing control (S 53).The control unit 20 sets the smoothing torque sharing ratios by calculating the ratio of the maximum engine torque Tmg-max (or the minimum engine torque Tmg-min) to the moment of inertia Ti as the smoothing torque sharing ratio of the engine 3 and obtaining the remainder (100% smoothing torque sharing ratio of the engine 3) as the smoothing torque sharing ratio of the engagement-side friction elements.After the feedback gains for the engagement-side friction elements and the engine 3 are set according to the respective smoothing torque sharing ratios in this manner, the control unit 20 determines whether the shift control has ended (S 54), and if the shift control has not ended (No at S 54), it outputs the feedback gain sharing ratios (S 55), that is, performs the feedback control of the engagement-side friction elements and the feedback control of the engine 3 with the respective sharing gains. If the control unit 20 determines at the time t 46 that the shift control has ended (Yes at S 54), the smoothing control is ended (S 56).In the same manner as described above, the response of the motor 3 in the output control thereof is faster than the hydraulic response of the engagement-side friction members. Thus, starting the feedback control at the same time may result in a delay in the response of the engagement-side friction elements. Therefore, as shown in FIG. 11, the feedback control of the engagement-side friction elements starts at time t 43 which is a start time obtained based on time t 44 serving as the start time of the feedback control of the engine 3 while considering the amount of delay in response of the engagement-side friction elements and the smoothing torque sharing ratios.Accordingly, as shown in FIG. 11, decreasing the engagement-side friction element torque TB from the time t 43 to the torque transmitted to the wheel side to start decreasing the moment of inertia Ti to the input-related members (i.e., decrease the rotation change), and decreasing the motor torque Tmg (input torque Tin) from the time t 44 gradually decreases the moment of inertia Ti and finally decreases it to 0. At time t 45, the engagement state is established in which the engagement-side friction element torque TB serves as the torque transmitted to the wheel side, and the inertia phase is substantially finished. Accordingly, the engagement of the engagement side friction members is completed (full engagement) at time t 46, and the shift control is ended at time t 46.As described above, the smooth control of the power-non-shift-down also sets the smooth torque sharing ratios of the engine 3 and the engagement-side friction elements, and performs control to distribute, to the engine 3 and the engagement-side friction elements, the torque to be shared therebetween in the smooth control, based on the smooth torque sharing ratios. This can eliminate the need for changing the torque of the internal combustion engine 2 in the smoothing control, and thus prevent the variation such as the engine spin or the drop in the input rotational speed Nin that may occur when the smoothing control is performed using the internal combustion engine 2. Setting the smoothing torque sharing ratios of the engine 3 and the friction engagement elements can prevent the engine torque Tmg from being required to exceed the output limit torque of the engine 3 (the maximum engine torque Tmg-max or the minimum engine torque Tmg-min), and thus realizes good smoothing control that does not require the engine 3 and the friction engagement elements to share excessive torque.Because the smoothing torque sharing ratios are set based on the engagement state of the engagement-side friction elements in the inertia phase, the limit of torque that can be generated by the engagement-side friction elements can be prevented from being exceeded. Thus, good smoothing control can be realized.Because the feedback gains for the motor and the engagement-side friction elements are set in the feedback control of the smoothing control according to the respective smoothing torque sharing ratios, hunting in the feedback control or the like can be prevented to prevent deviation of the control. Thus, good feedback control can be realized.Because the start time of the feedback control of the engine and the start time of the feedback control of the engagement state of the friction engagement elements are set according to the respective smoothing torque sharing ratios, good feedback control can be realized in consideration of the engine control, the response of which is more rapid than the hydraulic response of the engagement-side friction elements, in particular.[Other Ways of Hybrid Drive Apparatus]While the present embodiment has been described above having the stepped speed change mechanism 7 that can achieve, for example, six forward speeds and one reverse speed, the present invention can be applied to a stepped speed change mechanism that can achieve, for example, three to five forward speeds or seven or more forward speeds; in other words, the present invention can be applied to any stepped speed change mechanism that performs the shifting by switching the engagement of the friction engagement elements.While in the present embodiment the hybrid drive device 5 in which the engine 3 is directly drivingly coupled to the input shaft 15 has been described, the present invention is not limited thereto, but may be applied to a hybrid drive device in which the engine is disposed on another parallel shaft and is coupled to the input shaft via a transmission mechanism or a chain.INDUSTRIAL APPLICABILITYThe hybrid drive device according to the present invention can be used in a vehicle such as a passenger car and a truck, and particularly can be suitably used in a vehicle that generates at least a part of an inertia moment during shifting from an engine torque and it is desired to prevent the occurrence of an uncomfortable feeling during shifting.DESCRIPTION OF THE REFERENCE NUMERALS2 Internal combustion engine 3 Engine 5 Hybrid drive device 7 Stepped speed change mechanism 15 Input member (input shaft) 20 Control device (control unit) C- 1 Friction engagement element (clutch) C- 2 Friction engagement element (clutch) C- 3 Friction engagement element (clutch) B- 1 Friction engagement element (brake) B- 2 Friction engagement element (brake) Nin Actual rotational speed of the input member (input rotational speed) Nin-targ Target input rotational speed Ti Moment of inertia Tmg Motor torque Tmg-max Power limit torque of the motor (maximum motor torque) Tmg-min Power limit torque of the motor (minimum motor torque) Tmg-lim Set value

Claims

A hybrid drive device (5) comprising: an input member (15) drivingly coupled to an internal combustion engine (2); a motor (3) drivingly coupled to the input member (15); a stepped speed change mechanism (7) capable of switching a speed of rotation of the input member (15) by changing an engagement state of friction engagement elements (C-1, C-2, C-3, B-1, B-2); and a control device (20) capable of controlling the engagement state of the friction engagement elements (C-1, C-2, C-3, B-1, B-2) at least during the switching and performing control such that a motor torque (Tmg) output from the motor (3) generates at least a part of a moment of inertia (Ti), that is necessary for rotation change of input-related members drive-coupled to the input member (15) during shifting, wherein the control device (20) sets a setting value (Tmg-lim) to a smaller one of absolute values of the output limit torque (Tmg-max, Tmg-min) of the engine (3) at times before and after shifting, the control device (20) limits the engine torque in an inertia phase to an absolute value equal to or less than the setting value (Tmg-lim), sets a target input rotational speed (Nin-targ) of the input member (15) during shifting, and controls the engagement state of the friction engagement elements that control the rotation change of the input-related members in the inertia phase, in order to generate the moment of inertia (Ti) calculated from the target input rotational speed (Nin-targ) in the input-related components, the control device (20) performs smoothing control to alleviate a change in the moment of inertia (Ti) in a final period of shifting, sets smoothing torque sharing ratios of the motor (3) and the friction engagement elements in the smoothing control, and performs control to distribute the torque to be shared by the motor (3) and the friction engagement elements in the smoothing control to the motor (3) and the friction engagement elements in the smoothing control, in the smoothing control, the control device (20) controls, in a feedback manner, the motor (3) and the engagement state of the friction engagement elements on the basis of an actual rotational speed (Nm) of the input member (15) with respect to the target rotational speed (Nin-targ), and sets a feedback gain for the motor (3) and a feedback gain for the friction engagement elements in the feedback control according to the smoothing torque sharing ratios, and the control device (20) sets a start time (t13, t23, t33, t43) of the feedback control of the motor (3) and a start time (t12, t22, t32, t42) of the feedback control of the engagement state of the friction engagement elements according to the respective smoothing torque sharing ratios.The hybrid drive device (5) according to claim 1, characterized in that the control device (20) sets the smoothing torque sharing ratios on the basis of the engagement state of the friction engagement elements that control the rotation change of the input-related members in the inertia phase.

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