JP2018096462A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the learning control of release-side indication pressure so that an undershoot is suppressed irrespective of a variation of hydraulic pressure and disturbance when a clutch-to-clutch gear change of a coast-down shift accompanied by regeneration is performed.SOLUTION: When an undershoot rotation number exceeds an upper limit value, and release standby indication pressure (release-side indication pressure) α is raised (S2), the reduction of the release standby indication pressure α is prohibited until a count value of a counter C being the number of times of a coast-down shift in which the undershoot rotation number is not smaller than the upper limit value reaches a set value Cs (YES in the determination of S4). Therefore, a state that the undershoot rotation number is smaller than the upper limit value is continued, and even in the clutch-to-clutch gear change of the coast-down shift to which negative torque (regeneration torque) is added by the regeneration control of a second rotating machine, the generation of the undershoot in which the undershoot rotation number largely exceeds the upper limit value due to a variation of hydraulic pressure and the lack of the hydraulic pressure caused by disturbance can be suppressed.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a vehicle control device, and more particularly to an improvement in learning control for a release-side command pressure of a hydraulic friction engagement device on a release side of a coast downshift accompanying regeneration.

  2. Description of the Related Art A vehicle having an automatic transmission that is disposed in a power transmission path between a rotating machine and a drive wheel and that is capable of switching a gear stage by clutch-to-clutch shift by engagement and release of a pair of hydraulic friction engagement devices is known. ing. The hybrid vehicle described in Patent Document 1 is one example, and the regenerative control of the rotating machine is performed during coasting (decelerated traveling in a power-off state), and the automatic transmission is downshifted (coast downshifted) during the coasting. ), The clutch-to-clutch shift is performed while regenerating with the rotating machine. Further, at the time of coast downshift, the release side command pressure of the release side hydraulic friction engagement device involved in the coast downshift is learned based on the undershoot amount of the input rotational speed of the automatic transmission. Yes. That is, the release side command pressure is learned and controlled so that the undershoot amount converges to a predetermined target value determined in consideration of shift response, shift shock, and the like.

  On the other hand, in clutch-to-clutch shifting, the output torque of the transmission drops in the torque phase and inertia phase during shifting (increase in braking torque). Regenerative torque reduction control that temporarily reduces is performed. In that case, since the change in the regenerative torque affects the undershoot at the time of clutch-to-clutch shifting, Patent Document 1 discloses a coast with regeneration by completing the reduction control of the regenerative torque in the torque phase before the start of the torque phase. The release side command pressure learning control related to downshift clutch-to-clutch shifting is appropriately executed.

International Publication No. 2012/056540

  However, in the case of coast-to-shift clutch-to-clutch shift with regeneration, negative torque (regenerative torque) is applied by regenerative control of the rotating machine even if the regenerative torque reduction control is completed before the start of the torque phase. Therefore, if the release-side command pressure is learned and controlled so that the undershoot amount converges to a predetermined target value, the robustness is low, and the underpressure greatly exceeds the target value due to hydraulic pressure variation and insufficient hydraulic pressure due to disturbance compared to engine-driven vehicles. Shooting could occur and the shift shock could be worsened.

  The present invention has been made in the background of the above circumstances, and the purpose of the present invention is to perform undershoot regardless of variations in hydraulic pressure or disturbances when coast-to-shift clutch-to-clutch shift with regeneration is performed. The learning control of the release side command pressure is performed so as to be suppressed.

  In order to achieve such an object, the present invention provides (a) a clutch-to-clutch transmission that is disposed in a power transmission path between a rotating machine and a drive wheel, and is engaged and released by a pair of hydraulic friction engagement devices. (B) In a vehicle control device that performs the clutch-to-clutch shift while regenerating with the rotating machine during a coast downshift of the automatic transmission. c) When the coast downshift is performed, based on the undershoot amount of the input rotational speed of the automatic transmission, the release side instruction pressure of the release side hydraulic friction engagement device involved in the coast downshift is set. (D) the learning control unit determines whether or not the undershoot amount exceeds a predetermined upper limit value, and the undershoot amount Increases the release-side command pressure when the upper limit value is exceeded, and reduces the release-side command pressure when the undershoot amount is less than or equal to the upper limit value, (e) the learning control unit, After the release-side command pressure is increased, the reduction of the release-side command pressure is limited until the number of coast downshifts in which the undershoot amount is determined to be equal to or less than the upper limit value reaches a predetermined set value. It is characterized by including a reduction limiting unit.

  According to a second aspect of the present invention, in the vehicle control apparatus according to the first aspect, the learning control unit reduces the release-side command pressure with a smaller hydraulic width than when the undershoot is less than the upper limit. It is characterized by.

  In such a vehicle control apparatus, after the undershoot amount exceeds the upper limit value and the release-side command pressure is increased, the number of coast downshifts in which the undershoot amount is determined to be equal to or less than the upper limit value is the set value. Since the reduction of the release side command pressure is limited until reaching the value, the state in which the undershoot amount is smaller than the upper limit value becomes longer, and coast downshift clutch toe where negative torque (regenerative torque) is applied by regenerative control of the rotating machine. Even in clutch shifting, the occurrence of undershoot that greatly exceeds the upper limit due to hydraulic pressure variations and disturbance due to disturbance is suppressed. In addition, when the undershoot amount exceeds the upper limit value, learning control is performed so as to increase the release-side command pressure, and since a relatively large value can be set as the upper limit value, compared to a case where the upper limit value itself is reduced, Learning control can be performed so that, for example, when the release-side command pressure is increased, an excessive undershoot is suppressed, so that a weak tie-up state in which the undershoot amount is substantially zero, for example.

  In the second invention, when the undershoot amount is less than or equal to the upper limit value, the hydraulic pressure width when reducing the release side command pressure is greater than the hydraulic pressure width when increasing the release side command pressure when the undershoot amount exceeds the upper limit value. Therefore, even after the number of coast downshifts when the undershoot amount is determined to be less than or equal to the upper limit value reaches the set value, the release side command pressure gradually decreases, and the undershoot amount becomes the upper limit value. A sufficiently small state is maintained for a long time, and the occurrence of undershoot that greatly exceeds the upper limit due to insufficient oil pressure due to variations in oil pressure or disturbance is more appropriately suppressed.

It is a figure explaining the schematic structure of the vehicle drive device with which the vehicle to which this invention is applied is provided, and is a figure explaining the principal part of the control function and various control systems for various control in a vehicle. 2 is an engagement operation table for explaining a plurality of AT gear stages of the mechanical stepped transmission unit of FIG. 1 and an engagement device that establishes the AT gear stages. It is a collinear diagram showing the relative relationship of the rotational speed of each rotation element in an electric continuously variable transmission part and a mechanical stepped transmission part. It is a figure explaining an example of the gear stage allocation table which allocated the some simulation gear stage to the some AT gear stage. It is the figure which illustrated on the nomograph the simulated 4th gear stage-simulated 6th gear stage established at the time of AT 2nd gear stage. It is a figure explaining an example of the simulation gear stage shift map used for the shift control of a some simulation gear stage. It is a circuit diagram explaining the hydraulic control circuit regarding clutch C1, C2 and brake B1, B2 of a mechanical stepped transmission part. It is an example of the time chart explaining the hydraulic control and regenerative torque control at the time of coast downshift being performed by the coast downshift control part of FIG. 6 is a flowchart for explaining learning control of a release standby instruction pressure of the release side frictional engagement device, which is executed by a learning control unit in FIG. 1. It is a figure explaining the learning value which changes according to the frequency | count of a shift by carrying out learning control of the release standby instruction | indication pressure according to the flowchart of FIG. It is a figure explaining another example of the vehicle to which this invention is applied, and is a schematic block diagram of the vehicle drive device.

  The present invention can be applied to an electric vehicle including only a rotating machine as a power source for traveling, and a hybrid vehicle including an engine in addition to the rotating machine. For example, (a) an electric differential unit capable of steplessly changing the rotational speed of the engine by torque control of the differential rotating machine and transmitting it to the intermediate transmission member; and (b) the intermediate transmission member and the drive wheel. And an automatic transmission capable of mechanically establishing a plurality of gear stages having different transmission gear ratios of the intermediate transmission member with respect to the output rotation speed. Applied. As the automatic transmission, for example, a planetary gear type stepped transmission is preferably used, but a pair of hydraulic friction engagement devices such as a constant mesh type stepped transmission that changes gears by switching a pair of input shafts. Various stepped transmissions whose gears can be switched by clutch-to-clutch shifting by engagement and release can be used.

  A coast downshift is a downshift during power-off decelerating (coast running) where the accelerator pedal is not depressed, and a coast downshift involving regeneration of a rotating machine is, for example, when the brake is depressed when the brake pedal is depressed. Although it is executed, it can also be executed when the brake is off when the brake pedal is not depressed. A common release-side command pressure may be used regardless of whether the brake is on or off, but separate release-side command pressures can be used when the brake is on and when the brake is off. Pressure learning control is performed separately. When a coast downshift is performed over the third and higher gear stages, the release side command pressure is individually determined for each type of coast downshift, and the release side command pressure learning control is performed individually.

  As the undershoot amount when learning the release side command pressure, for example, the maximum value of the actual input rotational speed reduction amount (undershoot rotational speed) with respect to the synchronous rotational speed of the gear stage before shifting is used. The time during which the input rotational speed is lower (undershoot time), or the integrated value thereof can also be used. The upper limit value of the undershoot amount is appropriately determined in consideration of the shift shock, the required shift time, etc., and the increase amount of the release side command pressure when the undershoot amount exceeds the upper limit value is set to a predetermined value in advance. However, for example, the increase width may be changed stepwise or continuously in accordance with the difference from the upper limit value. When the increase width is a constant value, the increase width is appropriately determined according to the upper limit value. For example, the increase width can be determined so as to be in a weak tie-up state in which the undershoot amount is substantially zero. As for the reduction range of the release side command pressure when the undershoot amount is less than or equal to the upper limit value, a constant value may be set in advance. For example, the reduction range is changed stepwise or continuously depending on the difference from the upper limit value. You may let them. In the second invention, when the undershoot amount is less than or equal to the upper limit value, the hydraulic pressure width when reducing the release side command pressure is greater than the hydraulic pressure width when increasing the release side command pressure when the undershoot amount exceeds the upper limit value. However, the implementation of the first invention is not necessarily limited. In the second invention, when the hydraulic pressure width at the time of reduction and increase of the release side command pressure is a constant value, the hydraulic width at the time of reduction is suitably in the range of about 1/2 to 1/10 of the hydraulic width at the time of increase. However, it is determined as appropriate including out of the range.

  After increasing the release side command pressure, the reduction of the release side command pressure is restricted until the number of coast downshifts in which the undershoot amount is determined to be below the upper limit reaches the set value. The pressure may be prohibited from being reduced, or the reduction hydraulic pressure width may be reduced. The set value can be set to an arbitrary value of 1 or more, and may be a constant value regardless of the type of coast downshift, but a different value may be set for each type of coast downshift. .

  In the learning control of the release-side command pressure, it is desirable to perform the learning control on the engagement-side command pressure and the standby time of the engagement-side hydraulic friction engagement device, but the learning control is influenced by each other. For example, it is desirable to perform the learning control on the release side after the learning control on the engagement side is completed. However, the learning control on the engagement side can be performed after the learning control on the release side is completed, or both learnings can be performed in parallel.

  In clutch-to-clutch shifting, output torque may drop in the torque phase, and it is desirable to perform torque phase compensation control to reduce the regenerative torque of the rotating machine so as to cancel the drop. In order to appropriately perform the learning control of the release side command pressure, it is desirable to complete the reduction of the regenerative torque before the torque phase starts, that is, before the undershoot of the input rotational speed occurs. However, the present invention can also be applied to the case where the torque phase compensation control is not performed, for example, when the drop of the output torque is slight, the torque phase compensation control is not necessarily required.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a schematic configuration of a vehicle drive device 12 provided in a vehicle 10 to which the present invention is applied, and a diagram illustrating a main part of a control system for various controls in the vehicle 10. is there. In FIG. 1, the vehicle drive device 12 includes an engine 14 and an engine 14 disposed on a common axis in a transmission case 16 (hereinafter referred to as a case 16) as a non-rotating member attached to the vehicle body. An electric continuously variable transmission unit 18 (hereinafter referred to as a continuously variable transmission unit 18) connected directly or indirectly via a damper (not shown) and a mechanical stepped gear connected to the output side of the continuously variable transmission unit 18. A transmission unit 20 (hereinafter referred to as a stepped transmission unit 20) is provided in series. Further, the vehicle drive device 12 includes a differential gear device 24 connected to an output shaft 22 that is an output rotating member of the stepped transmission unit 20, a pair of axles 26 connected to the differential gear device 24, and the like. Yes. In the vehicle drive device 12, the power output from the engine 14 and a second rotating machine MG <b> 2 (described later) is transmitted to the stepped transmission unit 20 unless otherwise distinguished, and the stepped transmission unit. 20 is transmitted to the drive wheels 28 of the vehicle 10 via the differential gear unit 24 and the like. The vehicle drive device 12 is preferably used in, for example, an FR (front engine / rear drive) type vehicle that is vertically installed in the vehicle 10. The continuously variable transmission unit 18 and the stepped transmission unit 20 are configured substantially symmetrically with respect to the rotational axis (the common axial center) of the engine 14 and the like. In FIG. Half are omitted.

  The engine 14 is a power source for driving the vehicle 10 and is a known internal combustion engine such as a gasoline engine or a diesel engine. In this engine 14, the engine torque Te is controlled by controlling the throttle valve opening, the intake air amount, the fuel supply amount, the ignition timing, and the like by an electronic control unit 80 described later. In the present embodiment, the engine 14 is coupled to the continuously variable transmission 18 without a fluid transmission such as a torque converter or a fluid coupling.

  The continuously variable transmission 18 is a power split mechanism that mechanically divides the power of the first rotating machine MG1 and the engine 14 into the first rotating machine MG1 and an intermediate transmission member 30 that is an output rotating member of the continuously variable transmission 18. Differential mechanism 32 and a second rotating machine MG2 connected to the intermediate transmission member 30 so as to be able to transmit power. The continuously variable transmission unit 18 is an electrical differential unit in which the differential state of the differential mechanism 32 is controlled by controlling the operating state of the first rotating machine MG1, and is an electrical continuously variable transmission. The first rotating machine MG1 corresponds to a differential rotating machine, and the second rotating machine MG2 is an electric motor that functions as a power source for traveling, and corresponds to a traveling driving rotating machine. The vehicle 10 is a hybrid vehicle including an engine 14 and a second rotating machine MG2 as a driving power source.

  The first rotating machine MG1 and the second rotating machine MG2 are rotary electric machines having a function as an electric motor (motor) and a function as a generator (generator), and are so-called motor generators. The first rotating machine MG1 and the second rotating machine MG2 are each connected to a battery 52 as a power storage device provided in the vehicle 10 via an inverter 50 provided in the vehicle 10, and are described later. By controlling the inverter 50 by 80, MG1 torque Tg and MG2 torque Tm, which are output torques (power running torque or regenerative torque) of each of the first rotating machine MG1 and the second rotating machine MG2, are controlled. The battery 52 is a power storage device that transfers power to each of the first rotating machine MG1 and the second rotating machine MG2.

  The differential mechanism 32 is configured by a single pinion type planetary gear device, and includes three rotation elements of a sun gear S0, a carrier CA0, and a ring gear R0 so as to be differentially rotatable. The engine 14 is connected to the carrier CA0 via a connecting shaft 34 so that the power can be transmitted, the first rotating machine MG1 is connected to the sun gear S0 so that the power can be transmitted, and the second rotating machine MG2 can be transmitted to the ring gear R0. It is connected to. In the differential mechanism 32, the carrier CA0 functions as an input element, the sun gear S0 functions as a reaction force element, and the ring gear R0 functions as an output element.

  The stepped transmission unit 20 is a stepped transmission that constitutes a part of a power transmission path between the intermediate transmission member 30 and the drive wheels 28. The intermediate transmission member 30 also functions as an input rotation member (AT input rotation member) of the stepped transmission unit 20. Since the second rotary machine MG2 is connected to the intermediate transmission member 30 so as to rotate integrally, the stepped transmission unit 20 uses a part of the power transmission path between the second rotary machine MG2 and the drive wheels 28. It is the stepped transmission which comprises. The stepped transmission unit 20 includes, for example, a plurality of planetary gear devices of a first planetary gear device 36 and a second planetary gear device 38, and a plurality of engagement devices (hereinafter, referred to as a clutch C1, a clutch C2, a brake B1, and a brake B2). This is a known planetary gear type automatic transmission provided with an engagement device CB unless otherwise distinguished.

  The engagement device CB is a hydraulic friction engagement device including a multi-plate or single-plate clutch or brake that is pressed by a hydraulic actuator, a band brake that is tightened by a hydraulic actuator, or the like. Each of the engagement devices CB has a torque capacity (engagement) according to the regulated engagement hydraulic pressure Pcb output from each of the linear solenoid valves SL1 to SL4 (see FIG. 7) in the hydraulic control circuit 54 provided in the vehicle 10. (Combined torque) Tcb is changed to switch the operating state (engaged or released state).

  The stepped transmission unit 20 is configured such that the rotating elements (sun gears S1, S2, carriers CA1, CA2, ring gears R1, R2) of the first planetary gear device 36 and the second planetary gear device 38 are directly or engaging devices CB. In part (or selectively) through the one-way clutch F 1, some of them are connected to each other, or are connected to the intermediate transmission member 30, the case 16, or the output shaft 22.

  The stepped transmission unit 20 has a gear ratio γat (= AT input rotational speed ωi / output rotational speed ωo) that differs depending on the engagement of a predetermined engagement device among the engagement devices CB. The gear stage is formed. In this embodiment, the gear stage formed by the stepped transmission unit 20 is referred to as an AT gear stage. The AT input rotation speed ωi is the rotation speed (angular speed) of the input rotation member of the stepped transmission unit 20 and is equal to the rotation speed of the intermediate transmission member 30 and is the rotation speed of the second rotating machine MG2. It is the same value as the MG2 rotational speed ωm. The AT input rotational speed ωi can be expressed by MG2 rotational speed ωm. The output rotation speed ωo is the rotation speed of the output shaft 22 that is the output rotation speed of the stepped transmission unit 20, and the output rotation of the entire transmission 40 including the continuously variable transmission unit 18 and the stepped transmission unit 20. It is also speed.

  For example, as shown in the engagement operation table of FIG. 2, the stepped transmission unit 20 includes a plurality of AT gear stages as ATs for the forward speed of the fourth speed from the AT first gear stage “1st” to the AT fourth gear stage “4th”. A gear stage is formed. The gear ratio γat of the AT 1st gear stage is the largest, and the gear ratio γat becomes smaller at the higher vehicle speed side (the higher AT 4th gear stage side). The engagement operation table in FIG. 2 summarizes the relationship between each AT gear stage and each operation state of the engagement device CB (engagement device engaged in each AT gear stage). Engagement, “Δ” indicates engagement during engine braking or coast downshift of the stepped transmission 20, and blank indicates release. Since the one-way clutch F1 is provided in parallel with the brake B2 forming the AT 1st gear stage, it is not necessary to engage the brake B2 at the time of start (acceleration). The coast downshift of the stepped transmission unit 20 is a vehicle speed-related value (for example, vehicle speed V) during deceleration traveling due to a decrease in drive request amount (for example, accelerator opening θacc) or accelerator off (accelerator opening θacc is zero or substantially zero). Among the power-off downshifts for which a downshift has been determined (requested) due to a decrease in the engine speed, the downshift is requested while the vehicle is in a deceleration traveling state with the accelerator off. Note that, by disengaging any of the engaging devices CB, the stepped transmission unit 20 is brought into a neutral state in which no AT gear stage is formed (that is, a neutral state in which power transmission is interrupted).

  The stepped transmission unit 20 uses an electronic control unit 80 (described later) to release the disengagement side engagement device of the engagement device CB and the engagement of the engagement device CB according to the accelerator operation of the driver, the vehicle speed V, and the like. By controlling the engagement of the engagement device, the AT gear stage to be formed is switched (that is, a plurality of AT gear stages are selectively formed). That is, in the shift control of the stepped transmission unit 20, for example, a so-called clutch toe is performed in which a shift is executed by, for example, switching of one of the engagement devices CB (that is, by switching between engagement and release of the engagement device CB). A clutch shift is executed. For example, in the downshift (2 → 1 downshift) from the AT 2nd gear to the AT1st gear, the brake B1 serving as the disengagement side engagement device is released as shown in the engagement operation table of FIG. Among the engaging devices (clutch C1 and brake B2) engaged at the AT 1st gear stage, the brake B2 serving as the engaging-side engaging device released before the 2 → 1 downshift is engaged. It is done. At this time, the release transient hydraulic pressure of the brake B1 and the engagement transient hydraulic pressure of the brake B2 are pressure-controlled according to a predetermined change pattern or the like.

  FIG. 7 is a circuit diagram showing a main part of a hydraulic control circuit 54 including linear solenoid valves SL1 to SL4 for controlling the engagement of the engagement device CB. The hydraulic control circuit 54 includes a mechanical oil pump 100 that is rotationally driven by the engine 14 and an electric oil pump (EOP) 104 that is rotationally driven by the pump electric motor 102 when the engine is not operating. As prepared. The hydraulic oil output from these oil pumps 100 and 104 is supplied to the line pressure oil passage 110 through the check valves 106 and 108, respectively, and a predetermined line pressure is controlled by a line pressure control valve 112 such as a primary regulator valve. Regulated to PL. A linear solenoid valve SLT is connected to the line pressure control valve 112. The linear solenoid valve SLT is electrically controlled by the electronic control unit 80, so that the modulator hydraulic pressure Pmo, which is a substantially constant pressure, is used as a source pressure. The signal pressure Pslt is output. When the signal pressure Pslt is supplied to the line pressure control valve 112, the spool 114 of the line pressure control valve 112 is biased by the signal pressure Pslt, and the spool 114 is changed while changing the opening area of the discharge passage 116. Is moved in the axial direction, the line pressure PL is adjusted according to the signal pressure Pslt. The line pressure PL is adjusted according to, for example, the accelerator opening degree θacc that is a required output amount. The linear solenoid valve SLT is an electromagnetic pressure regulating valve for adjusting the line pressure, and the line pressure control valve 112 is a hydraulic control valve that regulates the line pressure PL in accordance with the signal pressure Pslt supplied from the linear solenoid valve SLT. A line pressure adjusting device 118 is configured including the line pressure control valve 112 and the linear solenoid valve SLT.

  The hydraulic oil having the line pressure PL adjusted by the line pressure adjusting device 118 is supplied to the linear solenoid valves SL1 to SL4 through the line pressure oil passage 110. The linear solenoid valves SL1 to SL4 are arranged corresponding to the hydraulic actuators (hydraulic cylinders) 120, 122, 124, and 126 of the clutches C1 and C2 and the brakes B1 and B2, and are supplied from the electronic control unit 80. The output oil pressure (engagement oil pressure Pcb) is controlled in accordance with the engagement release command of the oil pressure control command signal Sat (the solenoid excitation current, the release-side oil pressure command value Pdra and the engagement-side oil pressure command value Papp in FIG. 8). As a result, the clutches C1 and C2 and the brakes B1 and B2 are individually engaged and disengaged, and any one of the AT gear positions from the AT1 speed gear stage “1st” to the AT4 speed gear stage “4th” is formed. These linear solenoid valves SL1 to SL4 are solenoid valves that selectively engage the clutches C1 and C2 and the brakes B1 and B2 in accordance with a hydraulic control command signal Sat supplied from the electronic control unit 80.

  FIG. 3 is a collinear diagram showing the relative relationship between the rotational speeds of the rotary elements in the continuously variable transmission 18 and the stepped transmission 20. In FIG. 3, three vertical lines Y1, Y2, Y3 corresponding to the three rotating elements of the differential mechanism 32 constituting the continuously variable transmission unit 18 indicate the sun gear S0 corresponding to the second rotating element RE2 in order from the left side. It is the g-axis representing the rotational speed, the e-axis representing the rotational speed of the carrier CA0 corresponding to the first rotational element RE1, and the rotational speed of the ring gear R0 corresponding to the third rotational element RE3 (that is, the stepped transmission unit 20). M-axis representing the input rotation speed). Further, the four vertical lines Y4, Y5, Y6, Y7 of the stepped transmission unit 20 are in order from the left to the rotation speed of the sun gear S2 corresponding to the fourth rotation element RE4 and to each other corresponding to the fifth rotation element RE5. Corresponding to the rotational speed of the coupled ring gear R1 and carrier CA2 (that is, the rotational speed of the output shaft 22), the rotational speed of the mutually coupled carrier CA1 and ring gear R2 corresponding to the sixth rotational element RE6, and the seventh rotational element RE7. It is an axis | shaft showing each rotational speed of the sun gear S1 to perform. The intervals between the vertical lines Y1, Y2, and Y3 are determined according to the gear ratio (tooth ratio) ρ0 of the differential mechanism 32. Further, the distance between the vertical lines Y4, Y5, Y6, Y7 is determined according to the gear ratios ρ1, ρ2 of the first and second planetary gear devices 36, 38. In the case of a single-pinion type planetary gear device, if the distance between the sun gear and the carrier is “1” in the relationship between the vertical axes of the collinear chart, the distance between the carrier and the ring gear is the gear ratio ρ (= sun gear). The number of teeth Zs / the number of teeth of the ring gear Zr).

  If expressed using the alignment chart of FIG. 3, in the differential mechanism 32 of the continuously variable transmission 18, the engine 14 (see “ENG” in the drawing) is connected to the first rotating element RE1, and the second rotating element The first rotating machine MG1 (see “MG1” in the drawing) is connected to RE2, and the second rotating machine MG2 (see “MG2” in the drawing) is connected to the third rotating element RE3 that rotates integrally with the intermediate transmission member 30. Thus, the rotation of the engine 14 is transmitted to the stepped transmission unit 20 via the intermediate transmission member 30. In the continuously variable transmission 18, the relationship between the rotational speeds of the sun gear S0, the carrier CA0, and the ring gear R0 is indicated by the straight lines L0 and L0R that cross the vertical line Y2.

  In the stepped transmission unit 20, the fourth rotation element RE4 is selectively connected to the intermediate transmission member 30 via the clutch C1, the fifth rotation element RE5 is connected to the output shaft 22, and the sixth rotation element RE6 is It is selectively connected to the intermediate transmission member 30 via the clutch C2 and selectively connected to the case 16 via the brake B2, and the seventh rotating element RE7 is selectively connected to the case 16 via the brake B1. ing. In the stepped transmission 20, each AT gear stage “1st”, “2nd”, “3rd” is generated by the straight lines L 1, L 2, L 3, L 4, LR crossing the vertical line Y 5 by the engagement release control of the engagement device CB. , “4th”, “Rev”, the relationship between the rotational speeds of the rotational elements RE4 to RE7 is shown.

  A straight line L0 and straight lines L1, L2, L3, and L4, which are indicated by solid lines in FIG. Is shown. In this hybrid travel mode, when the reaction mechanism torque, which is a negative torque by the first rotating machine MG1, is input to the sun gear S0 in the positive rotation with respect to the engine torque Te input to the carrier CA0 in the differential mechanism 32. In the ring gear R0, an engine direct torque Td [= Te / (1 + ρ) = − (1 / ρ) × Tg] that becomes a positive torque in the forward rotation appears. Then, depending on the required driving force, the total torque of the engine direct torque Td and the MG2 torque Tm is used as the driving torque in the forward direction of the vehicle 10, and any one of the AT gear stages from the AT 1st gear stage to the AT4th gear stage. Is transmitted to the drive wheel 28 via the stepped transmission 20 formed with the. At this time, the first rotating machine MG1 functions as a generator that generates negative torque in the positive rotation. The generated power Wg of the first rotating machine MG1 is charged in the battery 52 or consumed by the second rotating machine MG2. The second rotating machine MG2 outputs the MG2 torque Tm using all or part of the generated power Wg or using the power from the battery 52 in addition to the generated power Wg.

  Although not shown in FIG. 3, in the alignment chart in the motor travel mode in which the engine 14 is stopped and the motor travel is performed using the second rotary machine MG2 as a power source, the carrier CA0 is used in the differential mechanism 32. Is set to zero rotation, and MG2 torque Tm, which becomes positive torque in the forward rotation, is input to the ring gear R0. At this time, the first rotating machine MG1 connected to the sun gear S0 is in a no-load state and is idled by negative rotation. That is, in the motor travel mode, the engine 14 is not driven, the engine rotational speed ωe, which is the rotational speed of the engine 14, is zero, and the MG2 torque Tm (here, the power running torque of the positive rotation) is driven in the forward direction of the vehicle 10. Torque is transmitted to the drive wheels 28 through the stepped transmission 20 in which any one of the AT 1st gear to the AT4th gear is formed.

  A straight line L0R and a straight line LR indicated by broken lines in FIG. 3 indicate the relative rotational speeds of the rotating elements in the reverse travel in the motor travel mode. In reverse travel in this motor travel mode, MG2 torque Tm, which becomes negative torque by negative rotation, is input to ring gear R0, and the MG2 torque Tm is used as drive torque in the reverse direction of vehicle 10 to form the AT1 speed gear stage. Is transmitted to the drive wheel 28 via the stepped transmission 20. The electronic control unit 80, which will be described later, uses a forward motor torque in a state in which the AT1 speed gear stage is formed as the forward low vehicle speed (low side) gear stage among the AT1 speed gear stage to the AT4 speed gear stage. A reverse MG2 torque Tm (here, a reverse MG2 torque Tm (here, a power running torque that is a positive torque for positive rotation; in particular, expressed as MG2 torque TmF) that is opposite to a positive and negative MG2 torque Tm (here, a power running torque that is a positive rotation positive torque) Then, the reverse running can be performed by outputting from the second rotating machine MG2 a power running torque that is negative torque of negative rotation; in particular, expressed as MG2 torque TmR. Thus, in the vehicle 10 of the present embodiment, the reverse travel is performed by reversing the positive / negative of the MG2 torque Tm using the forward AT gear stage (that is, the same AT gear stage as when performing forward travel). In the stepped transmission unit 20, an AT gear stage dedicated to reverse travel that reverses the input rotation and outputs the output in the stepped transmission unit 20 is not formed. Even in the hybrid travel mode, the second rotary machine MG2 can be rotated negatively like the straight line L0R while the engine 14 is rotated in the positive rotation direction. Therefore, the reverse travel is performed similarly to the motor travel mode. Can be done.

  In the vehicle drive device 12, the carrier CA0 as the first rotating element RE1 to which the engine 14 is connected so as to be able to transmit power and the first rotating machine MG1 as the differential motor (differential rotating machine) can transmit power. The sun gear S0 as the connected second rotating element RE2 and the ring gear R0 as the third rotating element RE3 to which the second rotating machine MG2 as the driving electric motor (traveling driving rotating machine) is connected so that power can be transmitted. An electric transmission mechanism (electrical differential mechanism) that includes a differential mechanism 32 having three rotating elements and that controls the differential state of the differential mechanism 32 by controlling the operating state of the first rotating machine MG1. The continuously variable transmission 18 is configured. That is, the operating state of the first rotating machine MG1 includes the differential mechanism 32 to which the engine 14 is connected so as to be able to transmit power, and the first rotating machine MG1 that is connected to the differential mechanism 32 so as to be able to transmit power. Is controlled to constitute the continuously variable transmission 18 in which the differential state of the differential mechanism 32 is controlled. The continuously variable transmission 18 has a transmission gear ratio γ0 (= ωe / ωm) of the rotational speed of the connecting shaft 34 (that is, engine rotational speed ωe) with respect to MG2 rotational speed ωm, which is the rotational speed of the intermediate transmission member 30, continuously. ) Is operated as an electric continuously variable transmission.

  For example, in the hybrid travel mode, the first rotating machine MG1 has a rotational speed of the ring gear R0 that is constrained by the rotation of the drive wheels 28 by forming a predetermined AT gear stage in the stepped transmission 20. When the rotational speed of the sun gear S0 is increased or decreased by controlling the rotational speed, the rotational speed of the carrier CA0 (that is, the engine rotational speed ωe) is increased or decreased. Accordingly, in engine running, the engine 14 can be operated at an efficient operating point. That is, the transmission 40 can constitute a continuously variable transmission as a whole by the stepped transmission 20 formed with a predetermined AT gear stage and the continuously variable transmission 18 operated as a continuously variable transmission.

  Further, since the continuously variable transmission 18 can be shifted like a stepped transmission, the continuously variable transmission 20 formed with an AT gear and the continuously variable transmission that shifts like a stepped transmission. 18, the entire transmission 40 can be shifted like a stepped transmission. In other words, in the transmission 40, a stepped gear is formed so as to selectively establish a plurality of gear stages (referred to as simulated gear stages) having different speed ratios γt (= ωe / ωo) of the engine rotational speed ωe with respect to the output rotational speed ωo. The transmission unit 20 and the continuously variable transmission unit 18 can be cooperatively controlled. The gear ratio γt is a total gear ratio formed by the continuously variable transmission unit 18 and the stepped transmission unit 20 arranged in series, and the gear ratio γ0 of the continuously variable transmission unit 18 and the stepped transmission unit 20 are A value obtained by multiplying the gear ratio γat (γt = γ0 × γat).

  The simulated gear stage is, for example, for each AT gear stage of the stepped transmission unit 20 by a combination of each AT gear stage of the stepped transmission unit 20 and the gear ratio γ0 of one or more types of continuously variable transmission unit 18. One or a plurality of types are assigned. For example, FIG. 4 is an example of a gear stage assignment (gear stage assignment) table. A simulated first gear stage to a simulated third gear stage are established for the AT first gear stage, and the AT second gear stage is established. A simulated 4-speed gear stage to a simulated 6-speed gear stage is established, a simulated 7-speed gear stage to a simulated 9-speed gear stage is established for the AT 3-speed gear stage, and a simulated 10-speed gear is established for the AT 4-speed gear stage. It is determined in advance so that the steps are established. FIG. 5 exemplifies a case where the simulated fourth gear to the simulated sixth gear are established when the AT gear of the stepped transmission unit 20 is the AT second gear on the same collinear diagram as FIG. Each of the simulated gears is established by controlling the continuously variable transmission 18 so that the engine speed ωe that achieves a predetermined gear ratio γt with respect to the output speed ωo.

  Returning to FIG. 1, the vehicle 10 includes an electronic control unit 80 that functions as a controller that controls the engine 14, the continuously variable transmission unit 18, the stepped transmission unit 20, and the like. FIG. 1 is a diagram showing an input / output system of the electronic control unit 80, and is a functional block diagram for explaining a main part of a control function by the electronic control unit 80. The electronic control unit 80 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, and the CPU uses a temporary storage function of the RAM according to a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. The electronic control unit 80 is divided into an engine control unit, a shift control unit, and the like as necessary. The electronic control device 80 corresponds to a control device for the vehicle 10.

  The electronic control unit 80 includes various sensors provided in the vehicle 10 (for example, an engine rotational speed sensor 60, an MG1 rotational speed sensor 62, an MG2 rotational speed sensor 64, an output rotational speed sensor 66, an accelerator opening sensor 68, a throttle valve). Various signals based on the detection values of the opening sensor 70, G sensor 72, shift position sensor 74, battery sensor 76, etc. (for example, engine rotational speed ωe, rotational speed MG1 of the first rotating machine MG1, MG1 rotational speed ωg, AT MG2 rotational speed ωm that is the input rotational speed ωi, output rotational speed ωo that corresponds to the vehicle speed V, and the accelerator opening that is the driver's acceleration operation amount (that is, the accelerator pedal operation amount) that represents the magnitude of the driver's acceleration operation. θacc, throttle valve opening θth, which is the opening of the electronic throttle valve, longitudinal acceleration G of the vehicle 10, and the vehicle 10 The operation position (operation position) POSsh of the shift lever 56 as a shift operation member, the battery temperature THbat of the battery 52, the battery charge / discharge current Ibat, the battery voltage Vbat, etc.) are supplied. Further, the electronic control device 80 provides various command signals (for example, an engine control device 58 such as a throttle actuator, a fuel injection device, an ignition device, an inverter 50, a hydraulic control circuit 54, etc.) provided in the vehicle 10. The engine control command signal Se for controlling the engine 14, the rotating machine control command signal Smg for controlling the first rotating machine MG1 and the second rotating machine MG2, the operating state of the pump motor 102 and the engaging device CB are controlled. Hydraulic control command signal Sat or the like (for controlling the shift of the stepped transmission 20) is output. The hydraulic control command signal Sat is, for example, a command signal (drive current) for driving the linear solenoid valves SL1 to SL4 that regulate the engagement hydraulic pressure Pcb supplied to the hydraulic actuators 120 to 126 of the engagement device CB. ) And output to the hydraulic control circuit 54. The electronic control unit 80 sets hydraulic pressure command values (indicated pressures) Pdra and Papp corresponding to the values of the engagement hydraulic pressures Pcb supplied to the hydraulic actuators 120 to 126, and sets the hydraulic pressure command values Pdra and Papp to the hydraulic pressure command values Pdra and Papp. The corresponding drive current is output.

  The operation position POSsh of the shift lever 56 is, for example, a P, R, N, D operation position. In the P operation position, the transmission 40 is set to the neutral state (for example, the stepped transmission 20 is set to the neutral state in which power cannot be transmitted by releasing any of the engagement devices CB), and the rotation of the output shaft 22 is mechanically prevented. This is a parking operation position for selecting the locked parking position (P position) of the transmission 40. The R operation position is the reverse travel position (R) of the transmission 40 that allows the reverse travel of the vehicle 10 with the reverse MG2 torque TmR in the state where the AT 1st gear stage “1st” of the stepped transmission 20 is formed. This is the reverse drive operation position for selecting (Position). The N operation position is a neutral operation position for selecting the neutral position (N position) of the transmission 40 in which the transmission 40 is in the neutral state. The D operation position is set by using all the AT gear speeds of the AT 1st gear stage “1st” to the AT 4th gear stage “4th” of the stepped transmission 20 (for example, the simulated 1st gear stage to the simulated 10th gear stage). This is a forward travel operation position for selecting a forward travel position (D position) of the transmission 40 that enables automatic travel control (using all simulated gears) and enables forward travel. The shift lever 56 functions as a switching operation member that receives a request for switching the shift position of the transmission 40 by being manually operated.

  The electronic control unit 80 calculates the state of charge (remaining power storage) SOC of the battery 52 based on, for example, the battery charge / discharge current Ibat and the battery voltage Vbat. Further, the electronic control unit 80 is configured to control the chargeable power (inputtable power) Win that regulates the input power limit of the battery 52 and the output power of the battery 52 based on the battery temperature THbat and the charge state SOC of the battery 52, for example. The dischargeable power (output possible power) Wout that defines the limit is calculated. The chargeable / dischargeable powers Win and Wout are, for example, lower as the battery temperature THbat is lower in the low temperature range where the battery temperature THbat is lower than the normal range, and lower as the battery temperature THbat is higher in the high temperature range where the battery temperature THbat is higher than the normal range. It will be lost. In addition, for example, in a region where the state of charge SOC is large, the chargeable power Win is reduced as the state of charge SOC is increased. For example, in the region where the state of charge SOC is small, the dischargeable power Wout is reduced as the state of charge SOC is small.

  The electronic control unit 80 includes a hybrid control unit 82 that functions as a hybrid control unit and an AT transmission control unit 90 that functions as an AT transmission control unit in order to execute various controls in the vehicle 10.

  The AT shift control unit 90 performs a shift determination of the stepped transmission unit 20 using a relationship (for example, an AT gear shift map) that has been experimentally or designally determined and stored (that is, predetermined) (for example, an AT gear shift map). The solenoid valve SL1 to SL4 sets the engagement disengagement state of the engagement device CB so that the shift control of the stepped transmission unit 20 is executed as necessary and the AT gear of the stepped transmission unit 20 is automatically switched. A hydraulic control command signal Sat for switching is output to the hydraulic control circuit 54. The AT gear shift map is defined by shift conditions, for example, a shift line indicated by “AT” in FIG. 6, a solid line is an upshift line, a broken line is a downshift line, and a predetermined hysteresis. Is provided. This shift map has, for example, two-dimensional coordinates with the output rotational speed ωo (here, the vehicle speed V and the like agreed) and the accelerator opening θacc (here, the requested drive torque Tdem and the throttle valve opening θth etc. also agreed) as variables. As the output rotational speed ωo becomes higher, the gear ratio γat is switched to the lower AT gear stage on the high vehicle speed side (high side), and as the accelerator opening θacc becomes larger, the gear ratio γat becomes larger on the lower vehicle speed side ( It is set to switch to the AT gear position on the low side.

  The hybrid control unit 82 functions as an engine control unit that controls the operation of the engine 14, that is, an engine control unit, and a rotating machine control unit that controls the operation of the first rotating machine MG1 and the second rotating machine MG2 via the inverter 50. That is, it includes a function as a rotating machine control unit, and performs hybrid drive control by the engine 14, the first rotating machine MG1, and the second rotating machine MG2 by these control functions. For example, the required drive power Pdem (or, in other words, the required drive torque Tdem at the vehicle speed V at that time) is calculated based on the accelerator opening θacc and the vehicle speed V, and the chargeable / dischargeable power Win, Wout of the battery 52 is taken into consideration. Then, command signals (engine control command signal Se and rotating machine control command signal Smg) for controlling the engine 14, the first rotating machine MG1, and the second rotating machine MG2 are output so as to realize the required driving power Pdem. . The engine control command signal Se is, for example, a command value of the engine power Pe that outputs the engine torque Te at the engine rotational speed ωe at that time. The rotating machine control command signal Smg is, for example, a command value of the generated power Wg of the first rotating machine MG1 that outputs a reaction torque of the engine torque Te (MG1 torque Tg at the MG1 rotation speed ωg at that time), and This is a command value for the power consumption Wm of the second rotating machine MG2 that outputs the MG2 torque Tm at the MG2 rotational speed ωm.

  Further, when the continuously variable transmission 18 is operated as a continuously variable transmission and the transmission 40 as a whole is operated as a continuously variable transmission, the engine power Pe that realizes the required drive power Pdem in consideration of the engine optimum fuel consumption point and the like. The continuously variable transmission control of the continuously variable transmission 18 is performed by controlling the engine 14 and the generated power Wg of the first rotating machine MG1 so that the engine rotational speed ωe and the engine torque Te are obtained. Thus, the gear ratio γ0 of the continuously variable transmission unit 18 is changed. As a result of this control, the overall gear ratio γt when the transmission 40 is operated as a continuously variable transmission is controlled.

  The hybrid control unit 82 also functionally includes a simulated stepped control unit 84 that shifts the continuously variable transmission unit 18 like a stepped transmission and changes the speed of the entire transmission 40 like a stepped transmission. Yes. The simulated stepped control unit 84 determines a shift of the transmission 40 using a predetermined relationship (for example, a simulated gear shift map), and the AT gear stage of the stepped transmission 20 by the AT shift control unit 90 is determined. In cooperation with the shift control, the shift control of the continuously variable transmission unit 18 is executed so as to selectively establish a plurality of simulated gears. The plurality of simulated gears can be established by controlling the engine rotational speed ωe by the first rotating machine MG1 in accordance with the output rotational speed ωo so that the respective gear ratios γt can be maintained. The speed ratio γt of each simulated gear stage does not necessarily have to be a constant value over the entire range of the output rotational speed ωo, and may be changed within a predetermined range, and is limited by the upper limit or lower limit of the rotational speed of each part. May be added.

  Similar to the AT gear shift map, the simulated gear shift map is determined in advance using the output rotation speed ωo and the accelerator opening θacc as parameters. FIG. 6 is an example of the simulated gear shift map, where the solid line is the upshift line and the broken line is the downshift line. By switching the simulated gear stage according to the simulated gear stage shift map, the entire transmission 40 in which the continuously variable transmission unit 18 and the stepped transmission unit 20 are arranged in series has the same shift feeling as the stepped transmission. It is done. In the simulated stepped shift control for shifting the transmission 40 as a stepped transmission as a whole, for example, when a driving mode emphasizing driving performance such as a sports driving mode is selected by the driver, the required driving torque Tdem is relatively large. In this case, the transmission 40 may be executed in preference to the continuously variable transmission control that is operated as a continuously variable transmission as a whole, but the simulation stepped variable speed control is basically executed except for a predetermined execution limit. Also good.

  The simulated stepped shift control by the simulated stepped control unit 84 and the shift control of the stepped transmission unit 20 by the AT shift control unit 90 are executed in cooperation. In the present embodiment, 10 types of simulated gears from simulated 1st gear to simulated 10th gear are assigned to 4 types of AT gears ranging from AT 1st gear to AT4th gear. For this reason, when a shift between the simulated third speed gear stage and the simulated fourth speed gear stage (referred to as a simulated three-speed / fourth speed shift) is performed, between the AT first gear stage and the AT second gear stage. (AT1⇔2 shift) is performed, and when the simulated 6⇔7 shift is performed, the AT2⇔3 shift is performed, and when the simulated 9⇔10 shift is performed, the AT3⇔4 shift is performed. (See FIG. 4). For this reason, the AT gear speed shift map is determined so that the AT gear speed is changed at the same timing as that of the simulated gear speed. Specifically, the upshift lines “3 → 4”, “6 → 7”, “9 → 10” of the simulated gear stage in FIG. 6 are “1 → 2”, “2” of the AT gear stage shift map. → 3 ”and“ 3 → 4 ”(see“ AT1 → 2 ”described in FIG. 6). In addition, the downshift lines “3 ← 4”, “6 ← 7”, and “9 ← 10” of the simulated gear stage in FIG. 6 are “1 ← 2” and “2 ← 3” of the AT gear stage shift map. , “3 ← 4” and the downshift lines (see “AT1 ← 2” described in FIG. 6). Alternatively, an AT gear shift command may be output to the AT shift control unit 90 based on the determination of the simulated gear shift based on the simulated gear shift map of FIG. Thus, the AT shift control unit 90 switches the AT gear stage of the stepped transmission unit 20 when the simulated gear stage is switched. Since the AT gear stage shift is performed at the same timing as the simulated gear stage shift timing, the stepped transmission section 20 is shifted with a change in the engine rotational speed ωe. Even if there is a shock associated with shifting, it is difficult for the driver to feel uncomfortable.

  The hybrid control unit 82 selectively establishes the motor travel mode or the hybrid travel mode as the travel mode according to the travel state. For example, when the required drive power Pdem is in a motor travel region (for example, a low vehicle speed and low drive torque region) smaller than a predetermined threshold value, the engine 14 is stopped and travel is performed only by the second rotating machine MG2. On the other hand, when the motor drive mode is established, the hybrid drive mode is established in which the engine 14 is operated to run when the requested drive power Pdem is in the engine drive region where the predetermined drive power is greater than or equal to a predetermined threshold value. In the hybrid travel mode, electric energy from the first rotating machine MG1 and / or electric energy from the battery 52 to be regeneratively controlled is supplied to the second rotating machine MG2, and the second rotating machine MG2 is driven (power running control). By applying torque to the drive wheels 28, torque assist for assisting the power of the engine 14 is executed as necessary. Even in the motor travel region, the hybrid travel mode is established when the state of charge SOC of the battery 52 and the dischargeable power Wout are less than a predetermined threshold. Regardless of whether the engine 14 is traveling or stopped, the engine 14 is started when the motor traveling mode is shifted to the hybrid traveling mode, for example, by increasing the engine rotational speed ωe and cranking the first rotating machine MG1. it can.

  The hybrid control unit 82 further includes a regeneration control unit 86 that functions as regeneration control means. The regenerative control unit 86 regeneratively controls the second rotating machine MG2 to charge the battery 52 and generate a predetermined braking force during coast travel, which is accelerator-off, that is, power-off decelerated travel. The regenerative torque (MG2 torque) Tm may be a constant value or may be changed according to the vehicle speed V. Further, when the brake is depressed and the brake is turned on, the regenerative torque Tm may be made larger than when the brake is not depressed and the regenerative torque Tm can be changed according to the brake operation force. In this embodiment, the regenerative control is performed regardless of whether the brake is on or off. However, the regenerative control may be performed only when the brake is on, and the regenerative control may not be performed when the brake is off.

  On the other hand, the AT shift control unit 90 includes a coast downshift control unit 92 that functions as a coast downshift control unit, a hydraulic storage unit 94 that functions as a hydraulic storage unit, and a learning control unit 96 that functions as a learning control unit. Yes. The coast downshift control unit 92 executes shift control when the stepped transmission unit 20 is downshifted as the vehicle speed V decreases during coasting, and is apparent from the engagement operation table shown in FIG. As described above, the AT gear stage is switched by clutch-to-clutch shift by engagement and release of the pair of engagement devices CB. Specifically, in the case of a coast downshift from the AT 4th gear stage “4th” to the AT 3rd gear stage “3rd”, the brake B1 is released and the clutch C1 is engaged, and from the AT 3rd gear stage “3rd” to AT2 In the case of the coast downshift to the speed gear stage “2nd”, the clutch C2 is released and the brake B1 is engaged, and in the case of the coast downshift from the AT2 speed gear stage “2nd” to the AT1 speed gear stage “1st”, The brake B1 is released and the brake B2 is engaged.

  FIG. 8 is an example of a time chart for explaining the change of each part when downshifting from the AT third gear stage “3rd” to the AT second gear stage “2nd”, and the time t1 is the time when the shift determination is made. At time t2, a hydraulic control command signal Sat for performing actual clutch-to-clutch shift is output. More specifically, the release side hydraulic pressure command value Pdra for releasing the clutch C2 is immediately reduced to, for example, a predetermined release standby instruction pressure α and held at the release standby instruction pressure α for a certain standby time. After that, it is lowered at a constant rate of change. The release side hydraulic pressure command value Pdra corresponds to the engagement hydraulic pressure Pcb of the release side engagement device CB, and the engagement hydraulic pressure Pcb is changed with a predetermined response delay. Further, the engagement hydraulic pressure command value Papp for engaging the brake B1 is maintained at a predetermined engagement standby instruction pressure β for a certain standby time following the first fill for packing, for example, and then the AT It is raised according to the change of the input rotational speed ωi. The engagement hydraulic pressure command value Papp corresponds to the engagement hydraulic pressure Pcb of the engagement device CB on the engagement side, and the engagement hydraulic pressure Pcb is changed with a predetermined response delay. The time t3 in FIG. 8 is the time when the start of the inertia phase in which the AT input rotational speed ωi is higher than the synchronous rotational speed before shifting obtained by multiplying the transmission gear ratio γatx of the AT gear stage before shifting and the output rotational speed ωo is made. It is. The time t4 is the time when the synchronization determination (shift end determination) in which the post-shift synchronous rotational speed obtained by multiplying the post-shift AT gear stage speed ratio γaty and the output rotational speed ωo substantially matches the AT input rotational speed ωi is made. When this synchronization determination is made, the engagement side hydraulic pressure command value Papp is increased to the maximum pressure, and a series of shift control ends. The release standby instruction pressure α corresponds to the release side instruction pressure, and the engagement standby instruction pressure β corresponds to the engagement side instruction pressure.

  Here, the release standby instruction pressure α and the engagement standby instruction pressure β are stored in advance in the hydraulic pressure storage unit 94 and are corrected by the learning control unit 96. That is, in the coast downshift, it is necessary to increase the AT input rotational speed ωi by the engagement torque of the engagement device CB while releasing the engagement device CB on the release side, and to advance the shift. The release standby instruction pressure α and the engagement standby instruction pressure β are set to the learning control unit 96 so that the AT input rotational speed ωi is prevented from greatly undershooting or tying up regardless of individual differences or changes with time. Is corrected by learning. The release standby instruction pressure α and the engagement standby instruction pressure β are stored and learned and corrected for each type of coast downshift, that is, for each engagement device BC involved in the downshift. In addition, it is possible to individually store and correct the learning according to the state of the vehicle such as the presence or absence of a brake operation.

  In the coast-down shift clutch-to-clutch shift, the transmission output torque drops in the torque phase and inertia phase during shifting (increase in braking torque). The regenerative torque reduction control for temporarily reducing the regenerative torque Tm of the second rotating machine MG2 is performed by 86. The torque phase compensation control and the inertia phase compensation control in the column of MG2 torque Tm in the time chart of FIG. 8 specifically illustrate this regenerative torque reduction control, and the broken line indicates the AT input rotational speed ωi associated with the shift. This is the regenerative torque Tm that is equal power regardless of the change. In addition, if the MG2 torque Tm is changed, it may affect the change in the AT input rotational speed ωi accompanying the shift, and may further affect the learning control by the learning control unit 96. Before starting, the reduction control of the regenerative torque Tm by the torque phase compensation control is completed.

  The learning control unit 96 executes learning control of the engagement standby command pressure β prior to learning control of the release standby command pressure α. In the learning correction of the engagement standby instruction pressure β, for example, the engagement standby instruction pressure β is increased or decreased so that the inertia phase start required time tine (see FIG. 8) becomes a predetermined target value. For example, as shown in FIG. 8, the inertia phase start required time tine is from the time point when the engagement side hydraulic pressure command value Papp starts to rise after being held at the engagement standby command pressure β for a certain period of time until the start of the inertia phase (time t3). Although it is the time, it may be the time from the start of the shift control (time t2) to the start of the inertia phase. The target value is determined for each type of coast downshift, for example. When the inertia phase start required time tine is shorter than the target value, the engagement standby instruction pressure β is reduced, and the inertia phase start required time tine is less than the target value. If it is longer, the engagement standby instruction pressure β is increased. The target value at the time of increase / decrease is provided with a predetermined hysteresis. The number of shifts Sh1 in the time chart of FIG. 10 is the time when the learning correction of the engagement standby instruction pressure β is completed and the engagement side learning completion flag is turned ON, after which the learning control of the release standby instruction pressure α is performed. Be started. In FIG. 10, the engagement standby instruction pressure β is reduced by a constant hydraulic pressure range, but the hydraulic pressure range for one learning correction may be changed according to the deviation from the target value. The engagement side learning completion flag is provided for each type of coast downshift, and is reset from ON to OFF under certain conditions, for example, when the number of executions of the same type of coast downshift reaches a predetermined value. Learning control of the combined standby instruction pressure β is periodically performed.

  The learning control of the release standby instruction pressure α is performed, for example, according to steps S1 to S6 (hereinafter simply referred to as S1 to S6) in the flowchart of FIG. The learning control unit 96 includes a reduction limiting unit 98 that functions as a reduction limiting unit in relation to the learning control of the release standby instruction pressure α, and S3, S4, and S6 in the flowchart of FIG. Equivalent to.

The flowchart of FIG. 9 is executed every time the same type of coast downshift is performed on condition that the engagement side learning completion flag is ON. In S1, the undershoot rotation speed nund at the coast downshift is performed. Whether or not exceeds a predetermined upper limit value ns. As shown in FIG. 8, the undershoot rotational speed nund is the maximum value of the decrease amount of the actual AT input rotational speed ωi with respect to the pre-shift synchronous rotational speed. This is the maximum value calculated according to (1). The difference in rotational speed from the synchronous rotational speed before shifting when the AT input rotational speed ωi becomes a minimum value may be regarded as the undershoot rotational speed nund. The upper limit value ns is determined in advance for each type of coast downshift in consideration of shift shock, shift required time, etc., and may be a constant value. However, the vehicle speed V, deceleration, presence / absence of brake operation, etc. You may change according to a state. In this embodiment, the undershoot rotation speed nund is the amount of undershoot, but the undershoot time tund when the AT input rotation speed ωi is lower than the synchronous rotation speed before shifting, and the undershoot rotation during the undershoot time tund. An integral value of several nund can also be used as the undershoot amount.
nund = ωo × γatx−ωi (1)

  If the determination in S1 is YES (ie, affirmative), that is, if nund> ns, S2 is executed, and the release standby instruction pressure α at the next coast downshift is increased so that undershoot is suppressed. Thus, the release standby instruction pressure α is learned and corrected. Specifically, the release standby command pressure α stored in the hydraulic pressure storage unit 94 is increased and overwritten, and the release side hydraulic command is used by using the new release standby command pressure α at the next coast downshift of the same type. Let the value Pdra be controlled. The increase range of the release standby instruction pressure α is set in advance in accordance with the upper limit value ns so that, for example, a low tie-up state in which the undershoot rotation speed nund is approximately 0 is obtained. The number of shifts Sh2, Sh3, and Sh4 in the time chart of FIG. 10 is the time of a shift in which learning correction for increasing the release waiting instruction pressure α is performed by executing S2. In the next S3, a counter C that counts the number of executions of the same type of coast downshift is reset to zero.

  If the determination in S1 is NO (No), that is, if nund ≦ ns, S4 is executed to determine whether or not the count value of the counter C is equal to or greater than a predetermined set value Cs. Immediately after the release standby instruction pressure α is increased in the execution of S2, the counter C is reset in S3, so the count value is 0, and S6 is executed to add 1 to the counter C. Each time the same type of coast downshift is executed, S6 is repeatedly executed following S1 and S4, whereby the counter C is incremented by one. When the set value Cs is reached, S5 is followed by S5. Is executed. In S5, the release standby instruction pressure α is learned and corrected so that the release standby instruction pressure α at the next coast downshift is reduced. Specifically, the release standby command pressure α stored in the hydraulic pressure storage unit 94 is reduced and overwritten, and the release side hydraulic command is used by using the new release standby command pressure α at the next coast downshift of the same type. Let the value Pdra be controlled. The reduction width of the release standby instruction pressure α is a constant value smaller than the increase width of S2, for example, set within a range of about 1/2 to 1/10 of the increase width, and the release standby instruction pressure α is gradually reduced. Is done. FIG. 10 shows a case where the reduction width is about 1/5 of the increase width.

  The set value Cs of S4 corresponds to the number of shifts in which the reduction of the release standby instruction pressure α is prohibited, and can be set to an arbitrary value of 1 or more. It is set within a range of about 20, and FIG. 10 shows a case where Cs = 6. The set value Cs may be a constant value regardless of the type of coast downshift, but a different value may be set for each type of coast downshift. Different values may be set for each case depending on the vehicle state such as presence / absence of brake operation, deceleration, or AT input torque. The graph of the release standby instruction pressure α in the lowermost stage in FIG. 10 is shown as a reference in the case where the reduction limit by the counter C is not performed, and is shown as a reference. In the present embodiment shown in the second stage, the release standby instruction pressure α is held in an increased state by the number of shifts corresponding to the set value Cs. In other words, for example, the undershoot rotational speed nund is maintained in a weak tie-up state where the undershoot rotational speed nund is substantially 0, although it varies depending on the increase width of the release standby instruction pressure α in S2.

  Thus, according to the electronic control unit 80 of the vehicle 10 of the present embodiment, when the undershoot rotational speed nund exceeds the upper limit value ns and the release standby instruction pressure α is increased in S2, the undershoot rotational speed nund is increased. Until the count value of the counter C, which is the number of coast downshifts determined to be the upper limit value ns or less, reaches the set value Cs (YES in S4), the reduction of the release standby instruction pressure α is prohibited. For this reason, a state in which the undershoot rotational speed nund is smaller than the upper limit value ns, specifically, a state in which the undershoot rotational speed nund is in a weak tie-up state in which the undershoot rotational speed nund is substantially 0 becomes long. As a result, even in a coast downshift clutch-to-clutch shift in which negative torque (regenerative torque) Tm is applied by the regenerative control of the second rotating machine MG2, an undershoot that greatly exceeds the upper limit value ns due to a hydraulic pressure variation or insufficient hydraulic pressure due to disturbance. Is suppressed.

  Further, when the undershoot rotational speed nund exceeds the upper limit value ns, learning control is performed so as to increase the release standby instruction pressure α, and a relatively large value can be set as the upper limit value ns. Therefore, the upper limit value ns itself is reduced. Compared to the case, the learning control can be performed so that, for example, the undershoot rotational speed nund is in a weak tie-up state when the release standby instruction pressure α is increased while suppressing an excessive undershoot.

  Further, when the undershoot rotational speed nund is less than or equal to the upper limit value ns, the hydraulic pressure width when the release standby instruction pressure α is reduced increases the release standby instruction pressure α when the undershoot rotational speed nund exceeds the upper limit value ns. Therefore, even after the number of coast downshifts in which the undershoot rotation speed nund is determined to be equal to or lower than the upper limit value ns, that is, after the count value of the counter C reaches the set value Cs, the release standby command pressure α Is gradually reduced, the state where the undershoot rotational speed nund is sufficiently smaller than the upper limit value ns is maintained for a long time, and an undershoot that greatly exceeds the upper limit value ns occurs due to insufficient oil pressure due to variations in hydraulic pressure or disturbance (Frequency and size) is more appropriately suppressed.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention can be applied also in another aspect.

  For example, in the above-described embodiment, the vehicle 10 including the continuously variable transmission unit 18 and the stepped transmission unit 20 in series is illustrated, but the present invention is not limited to this aspect. For example, a vehicle 200 as shown in FIG. 11 may be used. The vehicle 200 is a hybrid vehicle having an engine 202 as a driving power source and a rotating machine MG functioning as a power source, and includes a vehicle driving device 204. The rotating machine MG is a motor generator that is selectively used as an electric motor and a generator. The vehicle drive unit 204 also includes a clutch K0, a torque converter 208 with a lock-up clutch, a mechanical stepped transmission unit 210, and the like in order from the engine 202 side in a transmission case 206 as a non-rotating member attached to the vehicle body. And a differential gear device 212, an axle 214, and the like. The pump impeller 208a of the torque converter 208 is connected to the engine 202 via the clutch K0 and directly connected to the rotating machine MG. The turbine wheel 208b of the torque converter 208 is directly connected to the mechanical stepped transmission unit 210. In the vehicle drive device 204, the power of the engine 202 and / or the power of the rotating machine MG is the clutch K0 (when the power of the engine 202 is transmitted), the torque converter 208, the mechanical stepped transmission 210, the differential gear device. 212, the axle 214, etc. are sequentially transmitted to the drive wheel 216. The mechanical stepped transmission unit 210 is a planetary gear type automatic transmission and includes a plurality of hydraulic friction engagement devices, and the gear stage is switched by clutch-to-clutch shift.

  In such a vehicle 200 as well, a motor travel mode in which the engine 202 is stopped by traveling by the rotating machine MG by disengaging the clutch K0, or a hybrid travel mode in which the engine 202 is traveled is possible. When a coast downshift accompanied by regeneration by the rotating machine MG2 is performed as shown in FIG. 8 during traveling in the motor traveling mode or the hybrid traveling mode, the release standby instruction pressure α is determined according to the flowchart shown in FIG. Learning control can be performed, and the same effect as the above-described embodiment can be obtained.

  In implementing the present invention, the vehicle 200 does not include the engine 202, the clutch K0, and the torque converter 208, and the rotating machine MG is directly connected to the input side of the stepped transmission unit 210. May be. In short, if the vehicle includes a rotating machine that functions as a power source and a stepped transmission that forms part of a power transmission path between the rotating machine and drive wheels, the present invention is applied. Can do. In the vehicle 200, the torque converter 208 is used as the fluid transmission device, but other fluid transmission devices such as a fluid coupling having no torque amplifying action may be used. Further, the torque converter 208 may not necessarily be provided, or may be replaced with a simple clutch.

  In the above-described embodiment, the stepped transmission unit 20 is a planetary gear type automatic transmission in which a forward four-speed AT gear stage is formed, but is not limited to this mode. For example, it is a synchronous mesh type parallel twin-shaft automatic transmission, which has two input shafts, each of which has a hydraulic friction engagement device (clutch), and has an even gear stage and an odd gear stage. An automatic transmission such as a known DCT (Dual Clutch Transmission) which is a type of transmission that establishes

  In the above-described embodiment, the transmission 40 as a whole is provided with the simulated stepped control unit 84 that shifts like a stepped transmission, and the simulated gear stage is switched using the simulated gear stage shift map. It is not restricted to this aspect. For example, the simulated gear stage of the transmission 40 may be switched in accordance with a shift instruction from the driver using a shift lever 56 or an up / down switch.

  In the above-described embodiment, an embodiment in which 10 types of simulated gears are assigned to 4 types of AT gears is illustrated, but the present invention is not limited to this. Preferably, the number of stages of the simulated gear stage may be equal to or greater than the number of stages of the AT gear stage, and may be the same as the number of stages of the AT gear stage, but is preferably larger than the number of stages of the AT gear stage, for example, twice The above is appropriate. The transmission of the AT gear stage is performed so that the rotational speed of the intermediate transmission member 30 and the second rotating machine MG2 connected to the intermediate transmission member 30 is maintained within a predetermined rotational speed range. The gear speed is changed so that the engine rotational speed ωe is maintained within a predetermined rotational speed range, and the number of each stage is appropriately determined.

  Further, in the above-described embodiment, the differential mechanism 32 has a configuration of a single pinion type planetary gear device having three rotating elements, but is not limited thereto. For example, the differential mechanism 32 may be a differential mechanism having four or more rotating elements by connecting a plurality of planetary gear devices to each other. The differential mechanism 32 may be a double pinion type planetary gear device. In the differential mechanism 32 of the above embodiment, the engine 14 is connected to the rotation element RE1 (carrier CA0) positioned in the middle in the alignment chart of FIG. 3, but for example, the rotation element positioned in the middle of the alignment chart. Various modes are possible, such as an AT input rotation member (intermediate transmission member 30) being connected to the other.

  As mentioned above, although the Example of this invention was described in detail based on drawing, these are one Embodiment to the last, This invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.

  DESCRIPTION OF SYMBOLS 10,200: Vehicle 20,210: Mechanical stepped transmission unit (automatic transmission) 28: Drive wheel 80: Electronic control unit (control unit) 92: Coast downshift control unit 96: Learning control unit 98: Reduction limit unit MG2: second rotating machine (rotating machine, power source) MG: rotating machine (rotating machine, power source) C1, C2: clutch (hydraulic friction engagement device) B1, B2: brake (hydraulic friction engagement device) ωi: AT input rotational speed (input rotational speed) nund: Undershoot rotational speed (undershoot amount) tund: Undershoot time (undershoot amount) ns: Upper limit value α: Release standby command pressure (release side command pressure) C: Counter (number of shifts) Cs: Set value

Claims (2)

It is provided in a vehicle having an automatic transmission that is arranged in a power transmission path between a rotating machine and a drive wheel and that can change gear stages by clutch-to-clutch shift by engagement and release of a pair of hydraulic friction engagement devices. In the vehicle control device for performing the clutch-to-clutch shift while regenerating with the rotating machine at the time of a coast downshift of the automatic transmission,
When the coast downshift is performed, the release side command pressure of the release side hydraulic friction engagement device involved in the coast downshift is learned based on the undershoot amount of the input rotational speed of the automatic transmission. A learning control unit,
The learning control unit determines whether or not the undershoot amount exceeds a predetermined upper limit value, and when the undershoot amount exceeds the upper limit value, increases the release-side command pressure, When the undershoot amount is less than or equal to the upper limit value, the release side indicated pressure is reduced,
The learning control unit increases the release-side command pressure, and until the number of coast downshifts for which the undershoot amount is determined to be equal to or less than the upper limit value reaches a predetermined set value, A control device for a vehicle, comprising: a reduction limiting unit that limits the reduction of the command pressure. 2. The vehicle control device according to claim 1, wherein when the undershoot amount is equal to or less than the upper limit value, the learning control unit reduces the release-side command pressure with a hydraulic pressure smaller than that during the increase.

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