JP6485403B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device including an electric continuously variable transmission unit and a mechanical stepped transmission unit in series.

  And a differential mechanism having a first rotating element connected to the engine so that power can be transmitted, a second rotating element connected to the first rotating machine so as to transmit power, and a third rotating element connected to the intermediate transmission member. An electric continuously variable transmission whose differential state is controlled by the first rotating machine, a mechanical stepped transmission provided between the intermediate transmission member and the drive wheel, and power to the intermediate transmission member 2. Description of the Related Art A vehicle control device is well known that includes a second rotating machine that is connected so as to be able to transmit, and a power storage device that transfers power to each of the first rotating machine and the second rotating machine. For example, the engine rotation control device for vehicles described in patent document 1 is it. In this Patent Document 1, when it is determined that the start control of the engine using the first rotating machine is executed during the shift control of the mechanical stepped transmission unit, the start control is executed during the execution of the shift control, or It is disclosed that it is determined according to the vehicle state whether the start control is executed after the completion of the shift control.

JP 2009-47107 A

  By the way, the technique of Patent Document 1 is a technique in which the start control is executed even during the shift control when the responsiveness is emphasized as in the case of the acceleration request, and in other cases, the occurrence of the shock is performed. Reduction is emphasized, and the start control is executed after the shift control is completed. In other words, in the configuration in which the electric continuously variable transmission unit and the mechanical stepped transmission unit are arranged in series, the start of the engine connected to the electric continuously variable transmission unit affects the shift of the mechanical stepless transmission unit. Therefore, if the start control is executed during the shift control, a shock is likely to occur. Therefore, it is basically desirable not to execute the start control during the shift control. On the other hand, in the configuration in which the electric continuously variable transmission unit and the mechanical stepped transmission unit are arranged in series, when the shift of the mechanical stepped transmission unit is a downshift, the input rotation of the mechanical stepped transmission unit Since the speed (that is, the rotation speed of the second rotating machine or the rotation speed of the intermediate transmission member) increases, the rotation speed of the first rotating machine also becomes the rotation speed of the intermediate transmission member by the differential action of the electric continuously variable transmission unit. Rise proportionally. Therefore, in order to avoid or suppress the shock, if engine start control is executed after the downshift of the mechanical stepped transmission unit, the first electric power (charge power) to the power storage device at the time of the start control is obtained. The cranking power (= cranking torque (predetermined positive torque) × rotational speed of the first rotating machine (negative rotating speed)) that is electric power generated by the rotating machine is increased. Then, in the aspect in which the start control is executed after the downshift, the cranking power is insufficient due to the restriction of the input power of the power storage device, and the start control of the engine using the first rotating machine may be limited. Alternatively, when trying to avoid shortage of cranking power due to the limitation of the input power of the power storage device (that is, when starting control is performed while keeping the limitation of the input power of the power storage device), during the shift control without delaying the start control. There is a possibility that a shock will occur.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide an engine starter and a machine in a vehicle including an electric continuously variable transmission unit and a mechanical stepped transmission unit in series. Provided is a control device capable of avoiding the occurrence of shock due to the overlap with the shift of the variable stepped transmission unit and preventing the engine start from being limited by the limit of the input power of the power storage device after the shift. It is in.

  The gist of the first invention is that: (a) an engine is connected to an intermediate transmission member; a first rotating element that is connected to transmit power; a first rotating machine that is connected to transmit power; and a second rotating element. An electric continuously variable transmission that includes a differential mechanism having a third rotating element that is controlled to control a differential state of the differential mechanism by controlling an operating state of the first rotating machine; A mechanical stepped transmission that forms part of the power transmission path between the intermediate transmission member and the drive wheel and that is selectively formed with a plurality of gear stages, and is coupled to the intermediate transmission member so that power can be transmitted. A control device for a vehicle, comprising: a second rotating machine; and a power storage device that transmits and receives power to each of the first rotating machine and the second rotating machine, and (b) The next downshift of the mechanical stepped transmission unit during inertial running that has been stopped When executed, it is determined that the rotation speed of the intermediate transmission member is higher than a threshold value, and if it is determined that the next downshift is executed if deceleration traveling is continued at the current deceleration. Is an engine start control unit that executes start control for starting the engine using the first rotating machine, and (c) a threshold value that is set so that the threshold value decreases as the power that can be input to the power storage device decreases. And a setting unit.

  According to the first aspect of the present invention, when the next downshift of the mechanical stepped transmission unit is executed during inertial running, the rotation speed of the intermediate transmission member becomes smaller as the input power of the power storage device is lower. The first rotating machine is used when it is determined that the threshold value is higher than the threshold set in the above and when it is determined that the next downshift will be executed if deceleration traveling is continued at the current deceleration. Since engine start control is executed, if engine start control is executed during the next downshift execution (or after completion of the downshift), the engine start may be restricted due to the limitation of the power that can be input to the power storage device. The engine start control is executed before the next downshift is executed. Therefore, it is possible to avoid the occurrence of a shock due to the overlap of the engine start and the shift of the mechanical stepped transmission unit, and it is possible to prevent the engine start from being limited by the limit of the input power of the power storage device after the shift. . In addition, when the next downshift is executed, if the input power limit of the power storage device is not limited, the engine start control is executed after the next downshift, so that the frequency of unnecessary engine start is suppressed. The

It is a figure explaining the schematic structure of the power transmission device with which the present invention was equipped, and the principal part of the control function for various controls in vehicles, and a control system. It is a collinear diagram showing the relative relationship of the rotational speed of each rotation element in a power distribution mechanism, Comprising: It is a figure which shows an example at the time of driving | running | working. 2 is an operation chart for explaining a relationship between a shift operation of the automatic transmission exemplified in FIG. 1 and a combination of operations of engagement devices used therefor. The main part of the control operation of the electronic control unit, that is, the start of the engine and the coast downshift of the automatic transmission are avoided, and the start of the engine is limited by limiting the chargeable power of the battery after the shift. It is a flowchart explaining the control action for avoiding. It is an example of the time chart at the time of performing the control action shown to the flowchart of FIG.

  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 power transmission device 12 (hereinafter referred to as a power transmission device 12) provided in a vehicle 10 to which the present invention is applied, and for various controls in the vehicle 10. It is a figure explaining the principal part of a control system. In FIG. 1, a vehicle 10 is a hybrid vehicle including an engine 14, a first rotating machine MG1, and a second rotating machine MG2. The power transmission device 12 includes a power distribution mechanism as a differential mechanism in which the engine 14, the first rotating machine MG1, and the second rotating machine MG2 are connected to any one of a plurality of rotating elements (rotating members) so as to be able to transmit power. 16, and an automatic transmission (AT) 20 disposed between the power distribution mechanism 16 and the drive wheel 18. In the power transmission device 12, the power output from the engine 14 and the second rotating machine MG2 (the torque and the force are synonymous unless otherwise distinguished) is transmitted to the automatic transmission 20, and the differential gear from the automatic transmission 20 It is transmitted to the drive wheel 18 via the device 22 or the like. The power distribution mechanism 16 and the automatic transmission 20 are configured substantially symmetrically with respect to the center line (axial center RC), and the lower half of the axial center RC is omitted in FIG. 1 is a rotational axis of the engine 14, the power distribution mechanism 16, and the like.

  The engine 14 is a main power source of the vehicle 10 and is a known internal combustion engine such as a gasoline engine or a diesel engine. The engine 14 controls the engine torque Te by controlling an operating state such as a throttle valve opening θth or an intake air amount, a fuel supply amount, an ignition timing and the like by an electronic control unit 50 described later.

  The first rotating machine MG1 and the second rotating machine MG2 are so-called motor generators having a function as an electric motor (motor) for generating a driving torque and a function as a generator (generator). Each of the first rotating machine MG1 and the second rotating machine MG2 is connected to a battery 26 provided in the vehicle 10 via an inverter 24 provided in the vehicle 10, and is invertered by an electronic control device 50 described later. By controlling 24, MG1 torque Tg and MG2 torque Tm, which are output torques (power running torque or regenerative torque) of each of first rotating machine MG1 and second rotating machine MG2, are controlled. The battery 26 is a power storage device that transmits and receives electric power to each of the first rotating machine MG1 and the second rotating machine MG2.

  The power distribution mechanism 16 includes a sun gear S, a ring gear R arranged concentrically with the sun gear S, and a carrier CA that supports the sun gear S and the pinion gear P meshing with the sun gear S and the ring gear R so as to rotate and revolve. It is comprised from the well-known single pinion type planetary gear apparatus provided as a rotation element, and functions as a differential mechanism which produces a differential action. In the power transmission device 12, the engine 14 is connected to the carrier CA through a damper (not shown) so that power can be transmitted, the first gear MG1 is connected to the sun gear S so as to be able to transmit power, and the ring gear R is connected to the first gear. Two-rotary machine MG2 is connected so that power can be transmitted. In the power distribution mechanism 16, the carrier CA functions as an input element, the sun gear S functions as a reaction force element, and the ring gear R functions as an output element.

  The relative relationship between the rotational speeds of the rotating elements in the power distribution mechanism 16 is shown by the alignment chart of FIG. In this alignment chart, the vertical axis S (g axis), the vertical axis CA (e axis), and the vertical axis R (m axis) are the rotational speed of the sun gear S, the rotational speed of the carrier CA, and the rotational speed of the ring gear R. , And the vertical axis S, the vertical axis CA, and the vertical axis R have a mutual interval between the vertical axis S and the vertical axis R, where 1 is the interval between the vertical axis S and the vertical axis CA. The interval is set to be ρ (that is, the gear ratio (gear ratio) ρ of the power distribution mechanism 16) = the number of teeth Zs of the sun gear S / the number of teeth Zr of the ring gear R).

  A solid line and a two-dot chain line in FIG. 2 indicate when the shift stage (gear stage) of the automatic transmission 20 is low gear (for example, first gear stage) (see the solid line) and high gear (for example, second gear stage). This shows an example in which the time (see the two-dot chain line) is compared at the same vehicle speed V. Also, the solid line and the two-dot chain line in FIG. 2 indicate the relative speeds of the rotating elements in the hybrid travel mode in which the engine travels with at least the engine 14 as a drive source. In this hybrid travel mode, when the reaction force torque, which is negative torque by the first rotating machine MG1, is input to the sun gear S in the positive rotation with respect to the engine torque Te input to the carrier CA in the power distribution mechanism 16. In the ring gear R, an engine direct torque Td (= Te / (1 + ρ) = − (1 / ρ) × Tg) that becomes a positive torque in the forward rotation appears. Then, according to the required driving force, the combined torque of the engine direct torque Td and the MG2 torque Tm is transmitted to the driving wheel 18 via the automatic transmission 20 as the driving force in the vehicle forward direction. 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 26 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 26 in addition to the generated power Wg. When the power consumption Wm of the second rotating machine MG2 is the power that consumes all of the generated power Wg and does not include the power consumed by the battery 26, the charge / discharge power balance of the battery 26 is It becomes zero.

  As indicated by broken lines A and B in FIG. 2, in the collinear diagram in the motor travel mode in which the motor travels with the engine 14 stopped and traveled using the second rotating machine MG2 as a drive source, The carrier CA is set to zero rotation, and the ring gear R is input with MG2 torque Tm that becomes positive torque in the forward rotation. At this time, the first rotating machine MG1 connected to the sun gear S 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 Ne is set to zero, and the MG2 torque Tm (here, the positive running power running torque) is transmitted through the automatic transmission 20 as the driving force in the vehicle forward direction. It is transmitted to the drive wheel 18.

  In the power transmission device 12, the carrier CA as the first rotating element RE1 to which the engine 14 is connected so that power can be transmitted, and the first rotating machine MG1 as the differential motor (differential rotating machine) can transmit power. A power distribution mechanism 16 having three rotating elements, that is, a sun gear S as a connected second rotating element RE2 and a ring gear R as a third rotating element RE3 connected to the intermediate transmission member 28, includes a first rotation. The electric continuously variable transmission 30 (see FIG. 1) is configured as an electric continuously variable transmission that controls the differential state of the power distribution mechanism 16 by controlling the operating state of the machine MG1. That is, the engine 14 includes a power distribution mechanism 16 that is coupled to transmit power and the first rotating machine MG1 that is coupled to power distribution mechanism 16 so that the operating state of the first rotating machine MG1 is controlled. Thus, an electric continuously variable transmission 30 is configured as an electric transmission mechanism (electric differential mechanism) in which the differential state of the power distribution mechanism 16 is controlled. The electric continuously variable transmission 30 is operated as an electric continuously variable transmission that changes the gear ratio γ0 (= engine rotational speed Ne / MG2 rotational speed Nm), and the power of the engine 14 is transferred to the drive wheel 18 side. It is a continuously variable transmission for transmission. The intermediate transmission member 28 is an output rotation member of the electric continuously variable transmission 30. The second rotating machine MG2 is a traveling electric motor (traveling rotating machine) connected to the intermediate transmission member 28 so as to be able to transmit power.

  Returning to FIG. 1, the automatic transmission 20 is a mechanical transmission mechanism as a mechanical stepped transmission that forms part of the power transmission path between the intermediate transmission member 28 and the drive wheels 18. Therefore, the power transmission device 12 includes the electric continuously variable transmission 30 and the automatic transmission 20 in series. The automatic transmission 20 has, for example, a plurality of planetary gear devices and a plurality of engagement devices, and by re-holding any of the plurality of engagement devices (that is, by switching between engagement and release of the engagement devices). This is a known planetary gear type automatic transmission that performs a so-called clutch-to-clutch shift, in which a shift is executed. That is, the automatic transmission 20 is shifted by engagement and disengagement of the engaging device, and a plurality of gear ratios (gear ratios) γat (= AT input shaft rotational speed Ni / AT output shaft rotational speed No) are different. This is a stepped transmission portion in which the gears are selectively formed. The intermediate transmission member 28 is integrally connected to the ring gear R and is also integrally connected to a transmission input shaft (AT input shaft) 32 that is an input rotation member of the automatic transmission 20. Therefore, the AT input shaft rotational speed Ni is the same value as the rotational speed of the intermediate transmission member 28, and is the same value as the MG2 rotational speed Nm that is the rotational speed of the second rotating machine MG2. The rotational speed of the intermediate transmission member 28 can be expressed by AT input shaft rotational speed Ni or MG2 rotational speed Nm.

  Each of the plurality of engaging devices includes an AT input shaft 32 that receives power from the engine 14 and the second rotating machine MG2, and a transmission output that transmits power to the drive wheels 18 that are output rotating members of the automatic transmission 20. This is a hydraulic friction engagement device that transmits rotation and torque to and from a shaft (AT output shaft) 34. In these engagement devices, the torque capacity (clutch torque) is changed by adjusting the engagement hydraulic pressure (clutch hydraulic pressure) by a solenoid valve or the like in the hydraulic control circuit 36 provided in the automatic transmission 20. Engagement and release are controlled respectively. In the present embodiment, for convenience, the plurality of engaging devices are referred to as a clutch C, but the clutch C includes a known brake or the like in addition to the clutch.

  Here, the clutch torque of the clutch C is determined by, for example, the friction coefficient of the friction material of the clutch C and the clutch hydraulic pressure that presses the friction plate. Torque between the AT input shaft 32 and the AT output shaft 34 (for example, AT input torque that is input to the AT input shaft 32) without slipping the clutch C (that is, without causing the differential rotation speed of the clutch C). In order to transmit (Ti), a clutch torque is required to obtain a clutch transmission torque (that is, a shared torque of the clutch C) that must be handled by each clutch C with respect to the torque. However, in the clutch torque that provides the clutch transmission torque, the clutch transmission torque does not increase even if the clutch torque is increased. That is, the clutch torque corresponds to the maximum torque that can be transmitted by the clutch C, and the clutch transmission torque corresponds to the torque that the clutch C actually transmits. Therefore, in a state where the differential rotational speed is generated in the clutch C, the clutch torque corresponds to the clutch transmission torque. Note that the clutch torque (or clutch transmission torque) and the clutch hydraulic pressure are in a substantially proportional relationship except for the region where the clutch hydraulic pressure necessary for packing the clutch C is supplied.

  In the automatic transmission 20, the rotating elements (sun gears S1, S2, carriers CA1, CA2, and ring gears R1, R2) of the first planetary gear device 38 and the second planetary gear device 39 are directly or clutch C (clutch C1 , C2, brakes B1, B2) and one-way clutch F1 are indirectly (or selectively) partially connected to each other, AT input shaft 32, case 40 as a non-rotating member, or AT output shaft 34 It is connected to. Then, by each engagement release control of the clutch C, the four forward gear stages are established according to the driver's accelerator operation, the vehicle speed V, and the like, as shown in the engagement operation table of FIG. “1st” to “4th” in FIG. 3 mean the first gear (AT_1) to the fourth gear (AT_4) as the forward gear. The engagement operation table of FIG. 3 summarizes the relationship between each gear stage and each operation state of the clutch C, where “◯” indicates engagement, “Δ” indicates engagement during engine braking, and blank indicates release. Respectively. Since the one-way clutch F1 is provided in parallel to the brake B2 that establishes the first speed gear stage “1st”, it is not necessary to engage the brake B2 when starting (acceleration).

  Returning to FIG. 1, the vehicle 10 includes an electronic control device 50 including a control device for the vehicle 10, for example. Therefore, FIG. 1 is a diagram showing an input / output system of the electronic control device 50 and is a functional block diagram for explaining a main part of a control function by the electronic control device 50. The electronic control unit 50 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 50 executes output control of the engine 14, output control including regeneration control of the first rotating machine MG1 and the second rotating machine MG2, shift control of the automatic transmission 20, and the like. These are configured separately for engine control, for rotating machine control, for hydraulic control (for shift control), etc. as required.

  The electronic control device 50 includes various sensors provided in the vehicle 10 (for example, an engine rotation speed sensor 60, rotating machine rotation speed sensors 62 and 64 such as a resolver, a vehicle speed sensor 66, an accelerator opening sensor 68, a throttle valve opening sensor 70, Various actual values (for example, engine rotational speed Ne, which is the rotational speed of the engine 14, MG1 rotational speed Ng, which is the rotational speed of the first rotating machine MG1,) based on the detection signal detected by the battery sensor 72, etc. MG2 rotational speed Nm that is the rotational speed of the second rotating machine MG2 corresponding to the AT input shaft rotational speed Ni that is the rotational speed, AT output shaft rotational speed No that is the rotational speed of the AT output shaft 34 corresponding to the vehicle speed V, and driving Accelerator opening θacc, which is the amount of operation of the accelerator pedal as the amount of acceleration required by the user, throttle valve opening θth, which is the opening of the electronic throttle valve, Tteri a battery temperature of 26 THbat and battery charge and discharge current Ibat and the battery voltage Vbat) is supplied. Further, the electronic control unit 50 receives an engine control command signal Se for controlling the engine 14, a rotating machine control command signal Smg for operating the inverter 24 for controlling the first rotating machine MG1 and the second rotating machine MG2, A hydraulic control command signal Sat for controlling the clutch C related to the shift of the automatic transmission 20 is output. This hydraulic control command signal Sat is a command signal (hydraulic command value) for driving each solenoid valve that regulates each clutch hydraulic pressure supplied to each hydraulic actuator of the clutch C, for example, and is output to the hydraulic control circuit 36. Is done.

  The electronic control unit 50 calculates the state of charge (charge capacity) SOC of the battery 26 based on, for example, the battery charge / discharge current Ibat and the battery voltage Vbat. Further, the electronic control unit 50 determines, for example, the chargeable power (inputtable power) Win that defines the limit of the input power of the battery 26 and the output power of the battery 26 based on the battery temperature THbat and the charge capacity SOC of the battery 26. The dischargeable power (output possible power) Wout that defines the restriction is calculated. The chargeable / dischargeable powers Win and Wout are lower as the battery temperature THbat is lower in a low temperature range where the battery temperature THbat is lower than the normal range, and lower as the battery temperature THbat is higher in a 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 charge capacity SOC is large, the chargeable power Win is reduced as the charge capacity SOC is increased. Further, the dischargeable power Wout is reduced as the charge capacity SOC is decreased in a region where the charge capacity SOC is small, for example.

  The electronic control unit 50 includes a hybrid control unit, that is, a hybrid control unit 52, and a shift control unit, that is, a shift control unit 54, in order to realize various controls in the vehicle 10.

  The hybrid control unit 52 functions as an engine operation control unit that controls the operation of the engine 14, that is, an engine operation control unit, and a rotating machine that controls the operation of the first rotating machine MG1 and the second rotating machine MG2 via the inverter 24. A function as an operation control means, that is, a rotary machine operation control unit is included, and hybrid drive control by the engine 14, the first rotary machine MG1, and the second rotary machine MG2 is executed by these control functions. Specifically, the hybrid control unit 52 applies the accelerator opening θacc and the vehicle speed V to a relationship (for example, a driving force map) that is obtained experimentally or design in advance and stored (that is, a predetermined driving force map, for example). Thus, the required drive torque Tdem (that is, the required drive power Pdem at the vehicle speed V at that time) is calculated. The hybrid control unit 52 realizes the required drive power Pdem in consideration of the engine optimum fuel consumption point, transmission loss, auxiliary load, gear ratio γat of the automatic transmission 20, chargeable / dischargeable power Win, Wout of the battery 26, and the like. As described above, command signals (an engine control command signal Se and a rotary machine control command signal Smg) for controlling the engine 14, the first rotary machine MG1, and the second rotary machine MG2 are output. As a result of this control, the gear ratio γ0 of the electric continuously variable transmission 30 is controlled. The engine control command signal Se is a power command value for the engine 14. 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 the reaction torque (MG1 torque Tg) of the engine torque Te, and the second rotation that outputs the MG2 torque Tm. This is a command value for the power consumption Wm of the machine MG2.

  The hybrid control unit 52 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 that is smaller than a predetermined threshold, the hybrid control unit 52 establishes the motor travel mode while the required drive power Pdem is equal to or greater than a predetermined threshold. The hybrid travel mode is established in the engine travel region. Further, even when the required drive power Pdem is in the motor travel region, the hybrid control unit 52 establishes the hybrid travel mode if the charge capacity SOC of the battery 26 is less than a predetermined threshold value.

  When switching from the motor travel mode to the hybrid travel mode, the hybrid control unit 52 starts the engine 14 whose operation has been stopped. Therefore, the hybrid control unit 52 uses the first rotating machine MG1 to rotationally drive the engine 14 (that is, crank the engine 14), so that the engine start control unit that executes the start control that starts the engine 14, that is, the engine start control unit. 56 is functionally provided.

  The shift control unit 54 determines whether or not to shift the automatic transmission 20 according to a predetermined relationship (shift map). When the shift control unit 54 determines that the shift of the automatic transmission 20 should be executed, the shift control unit 54 engages and / or engages the clutch C involved in the shift of the automatic transmission 20 so as to form the determined gear stage. Alternatively, the hydraulic control command signal Sat to be released is output to the hydraulic control circuit 36, and the shift control of the automatic transmission 20 is executed.

  The shift map has a predetermined relationship having shift lines for determining shifts of the automatic transmission 20 on two-dimensional coordinates having, for example, the vehicle speed V (AT output shaft rotation speed No) and the accelerator opening θacc as variables. It is. Each shift line in the shift map is an up line for determining an upshift and a down line for determining a downshift. Each of these shift lines is whether or not the actual vehicle speed V crosses the line on a line indicating a certain accelerator opening θacc, or whether or not the actual accelerator opening θacc crosses the line on a line indicating a certain vehicle speed V, That is, it is for determining whether or not a value (shift point) at which the shift on the shift line is to be executed has been crossed, and is predetermined as a series of shift points. For example, it is set when the accelerator opening θacc is set to θy [%] in the down line for determining the downshift from the current gear stage (hereinafter referred to as the current gear stage) to the gear stage on the first gear side. The downshift point as a shift point is the next down vehicle speed Vx. In particular, during coasting where the accelerator is decelerated, the next down vehicle speed Vx is referred to as the next coast down vehicle speed Vxc. If the current vehicle speed (hereinafter referred to as the current vehicle speed) V is higher than the next down vehicle speed Vx, it is not determined that the downshift should be performed, while the current vehicle speed V is higher than the next down vehicle speed Vx. If it is low, it is determined that a downshift should be performed.

  By the way, in the power transmission device 12 including the electric continuously variable transmission 30 and the automatic transmission 20 in series, when the automatic transmission 20 is downshifted in the motor travel mode in which the operation of the engine 14 is stopped, the AT Since the input shaft rotational speed Ni (= MG2 rotational speed Nm) is increased, the differential action of the electric continuously variable transmission 30 also increases the MG1 rotational speed Ng in proportion to the MG2 rotational speed Nm (FIG. 2). (See broken lines A and B). On the other hand, in starting control of the engine 14 using the first rotating machine MG1, cranking power by the first rotating machine MG1 is necessary. This cranking power is generated power Wg (= cranking torque × Ng) of the first rotating machine MG1 represented by the product of cranking power that is a predetermined positive torque and MG1 rotational speed Ng that is a negative rotational speed. Therefore, the higher the MG2 rotational speed Nm, the higher the cranking power necessary for the start control (see the broken lines A and B and the dashed lines C and D in FIG. 2). On the other hand, it is desirable to execute the start control of the engine 14 using the first rotating machine MG1 while keeping the limit of the input power of the battery 26 (that is, within the range of the rechargeable power Win). Then, depending on the rechargeable power Win or the necessary cranking power, the cranking power that can actually be output is insufficient, and the start control of the engine 14 using the first rotating machine MG1 is limited (for example, the engine May not start). Therefore, when the cranking power is insufficient when the MG2 rotational speed Nm is increased due to the downshift of the automatic transmission 20, in order to avoid the engine starting being restricted, the downshift is being performed. It is conceivable that the engine 14 is started. However, since the start control of the engine 14 affects the shift control of the automatic transmission 20, a shock is likely to occur if the start control is executed during a downshift. In addition, when the downshift of the automatic transmission 20 is determined as the accelerator is turned on and switching from the motor travel mode to the hybrid travel mode is determined, acceleration response is prioritized over shock suppression. Thus, it is preferable to adopt a mode in which the downshift control and the start control are executed in an overlapping manner. Therefore, in this embodiment, a shock is generated when a downshift of the automatic transmission 20 (ie, coast downshift) is performed during inertial traveling in which the operation of the engine 14 is stopped, which is decelerated with the accelerator off. A control operation that avoids limiting engine start is proposed.

  Therefore, the electronic control unit 50 needs to start the engine due to insufficient cranking power in the next coast downshift (next coast downshift) (that is, the next coast downshift and engine start are When it is determined that the next coast downshift will be executed in the near future, the start control of the engine 14 is executed in advance prior to the start of the next coast downshift execution. .

  Specifically, the electronic control unit 50 avoids the occurrence of a shock due to the overlap of the downshift of the automatic transmission 20 and the engine start, and avoids the engine start being limited by the rechargeable power Win. In order to realize such control, vehicle state determination means, that is, a vehicle state determination unit 58, and threshold setting means, that is, a threshold setting unit 59 are further provided.

  The vehicle state determination unit 58 determines whether or not the MG2 rotational speed Nm becomes higher than the threshold value Nmcr when the next downshift of the automatic transmission 20 (that is, the next coast downshift) is executed during inertial traveling (that is, the next time). It is determined whether or not it is necessary to start the engine in a coast downshift. The threshold value Nmcr is, for example, the MG2 rotation speed Nm at which the cranking power is insufficient because the MG1 rotation speed Ng becomes high when exceeding this value, and is the current chargeable power Win (hereinafter referred to as current Win). The upper limit value (maximum value) of the MG2 rotational speed Nm that enables cranking of the engine 14 using the first rotating machine MG1.

  The vehicle state determination unit 58 determines whether or not it is necessary to start the engine in the next coast downshift based on whether or not the following equation (1) is satisfied (that is, the engine start and the downshift in the next coast downshift). Whether or not they are executed overlapping each other). In the following equation (1), “Noc” is the AT output shaft rotational speed No corresponding to the next coast down vehicle speed Vxc predetermined in the shift map or the like, and “γata” is the next coast down of the automatic transmission 20. The gear ratio γat after the shift, and “Nmcr” is the threshold value Nmcr set by the threshold value setting unit 59.

  Noc x γata> Nmcr (1)

  The threshold setting unit 59 sets the threshold Nmcr based on the current Win. Specifically, the threshold setting unit 59 sets the current Win to the maximum cranking power that can be output by the first rotating machine MG1, and the maximum MG1 rotation speed Ng (maximum MG1 rotation speed Ngcr that is possible with the current Win). ) (= Current Win / cranking torque). The threshold setting unit 59 sets the maximum value to the following equation (2) based on the relative relationship between the rotational speeds of the three rotating elements in the power distribution mechanism 16 (here, the engine rotational speed Ne is zero). The threshold value Nmcr is calculated by applying the MG1 rotation speed Ngcr. Note that the cranking torque is a predetermined value (for example, a predetermined value as the MG1 torque Tg necessary for cranking the engine 14 or a value changed according to the temperature of the engine 14), and ρ is This is the gear ratio ρ of the power distribution mechanism 16 described above. Thus, the lower the current Win, the lower the maximum MG1 rotation speed Ngcr and the lower the threshold Nmcr. That is, the threshold value setting unit 59 sets the threshold value Nmcr to be smaller as the chargeable power (inputtable power) Win (that is, current Win) of the battery 26 is lower.

  Nmcr = −ρ × Ngcr (2)

  The vehicle state determination unit 58 determines whether or not the next coast downshift is executed if the vehicle continues to decelerate at the current deceleration (hereinafter referred to as the current deceleration) during inertial traveling (that is, the next coast in the near future). Whether or not to perform downshifting). The vehicle state determination unit 58 determines whether or not to implement the next coast downshift in the near future based on whether or not the following equation (3) is satisfied. In the following equation (3), “V” is the current vehicle speed V, “dV / dt” is the current deceleration, “TMcr” is the engine start time TMcr, and “Vxc” is the next coast. The down vehicle speed is Vxc. Thus, instead of determining whether or not the current vehicle speed V has reached the next coast down vehicle speed Vxc, it is determined whether or not the vehicle speed V has reached the next coast down vehicle speed Vxc when the engine start time TMcr has elapsed from the present time. Judging. Therefore, when this determination is affirmed, the start control of the engine 14 is started, so that the next coast downshift control is started after the engine start is completed. Is done. The engine start time TMcr is, for example, a predetermined time as a time required from the start point of the start control to the completion point of the engine start or a time that is changed depending on the temperature of the engine 14 or the like.

  V−dV / dt × TMcr ≦ Vxc (3)

  The engine start control unit 56 determines that the MG2 rotational speed Nm is higher than the threshold value Nmcr when the next coast downshift of the automatic transmission 20 is executed by the vehicle state determination unit 58 during inertial traveling, and the vehicle state If it is determined by the determination unit 58 that the next coast downshift is to be executed when the deceleration traveling is continued at the current deceleration, the start control of the engine 14 is executed using the first rotating machine MG1.

  FIG. 4 shows an essential part of the control operation of the electronic control unit 50, that is, in the vehicle 10 having the electric continuously variable transmission 30 and the automatic transmission 20 in series. FIG. 5 is a flowchart for explaining a control operation for avoiding the occurrence of a shock due to the overlap of (downshift) and avoiding the engine start being limited by the limit of the chargeable power Win of the battery 26 after the shift, for example, Repeated during inertial running. FIG. 5 is an example of a time chart when the control operation shown in the flowchart of FIG. 4 is executed.

  In FIG. 4, first, in a step (hereinafter, step is omitted) S10 corresponding to the functions of the vehicle state determination unit 58 and the threshold setting unit 59, the threshold Nmcr is calculated using the equation (2). Whether or not it is necessary to start the engine in the next coast downshift is determined based on whether or not Expression (1) is satisfied. If the determination at S10 is negative, this routine is terminated. If the determination in S10 is affirmative, in S20 corresponding to the function of the vehicle state determination unit 58, whether or not to implement the next coast downshift in the near future based on whether or not the equation (3) is satisfied. Is determined. If the determination at S20 is negative, this routine is terminated. If the determination in S20 is affirmative, a start request for the engine 14 is made in S30 corresponding to the function of the engine start control unit 56, and the start control of the engine 14 is executed using the first rotating machine MG1.

  In FIG. 5, the time point t1 indicates that the 4 → 3 coast downshift has started. Before the start of the 4 → 3 coast downshift, it is not affirmed that it is necessary to start the engine in the next coast downshift (that is, whether to start the engine in the next coast downshift). → Even before the start of the 3-coast downshift, the engine start request will not be made even if the determination of whether to implement a coast downshift in the near future is affirmed. At time t2, it is determined that the MG2 rotational speed Nm becomes higher than the threshold value Nmcr when the next coast downshift is executed before the start of the 3 → 2 coast downshift after the execution of the 4 → 3 coast downshift is completed. It is shown that the determination of whether to start the engine at the next coast downshift is affirmed. In this state, the vehicle speed V decreases, and when it is affirmed that the coast downshift will be performed in the near future, an engine start request is made (see time t3). At time t4 when the 3 → 2 coast downshift is started, the engine start is completed. As a result, simultaneous control of downshift and engine start of the automatic transmission 20 (that is, at least a part of each control of downshift and engine start overlaps) is avoided. In the comparative example shown by the broken line, the start control of the engine 14 is started because the MG2 rotational speed Nm becomes higher than the threshold value Nmcr during execution of the 3 → 2 coast downshift. This shows that simultaneous control of downshift and engine start has been executed.

  As described above, according to the present embodiment, during coasting, when the next coast downshift of the automatic transmission 20 is executed, the MG2 rotational speed Nm decreases as the rechargeable power Win of the battery 26 decreases. Is determined to be higher than the threshold value Nmcr set to, and if it is determined that the next coast downshift is to be executed if deceleration traveling is continued at the current deceleration, the first rotating machine MG1 is used. Therefore, when the start control of the engine 14 is executed during the next coast downshift execution (or after the next coast downshift is completed), the engine start is limited by the limit of the rechargeable power Win of the battery 26. In such a case, the start control of the engine 14 is executed before the next coast downshift is executed. Therefore, it is possible to avoid the occurrence of shock due to the overlap of the engine start and the shift of the automatic transmission 20, and it is possible to avoid the engine start being limited by the limit of the rechargeable power Win of the battery 26 after the shift. If the limit of the rechargeable power Win of the battery 26 is not affected even when the next coast downshift is executed, the start control of the engine 14 is executed after the next coast downshift. It is suppressed.

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

  For example, in the above-described embodiment, the planetary gear in which each of the four forward gears is formed as a mechanical stepped transmission that forms part of the power transmission path between the intermediate transmission member 28 and the drive wheel 18. Although the automatic transmission 20 which is a type automatic transmission is illustrated, the present invention is not limited to this mode. For example, the automatic transmission 20 may be a planetary gear type multi-stage transmission in which a plurality of gear stages having different gear ratios are selectively formed by selectively engaging any of a plurality of engagement devices. It ’s fine. The mechanical stepped transmission unit is a known synchronous mesh type parallel two-shaft transmission having a plurality of pairs of gears that are always meshed between two shafts, and is engaged with a dog clutch (ie, a mesh clutch) by an actuator. A synchronous mesh type parallel twin-shaft automatic transmission whose release is controlled and the gear stage is automatically switched, and a well-known DCT (Dual) having two systems of input shafts in the synchronous mesh parallel two-shaft automatic transmission. It may be an automatic transmission such as Clutch Transmission.

  In the above-described embodiment, the power distribution mechanism 16 has a configuration of a single pinion type planetary gear device having three rotating elements, but is not limited thereto. For example, the power distribution mechanism 16 may be a differential mechanism having four or more rotating elements by connecting a plurality of planetary gear devices to each other. The power distribution mechanism 16 may be a double planetary planetary gear unit. The power distribution mechanism 16 may be a differential gear device in which the first rotating machine MG1 and the intermediate transmission member 28 are coupled to a pinion that is rotationally driven by the engine 14 and a pair of bevel gears that mesh with the pinion. good.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

10: Vehicle 14: Engine 16: Power distribution mechanism (differential mechanism)
CA: Carrier (first rotating element)
S: Sun gear (second rotating element)
R: Ring gear (third rotating element)
18: Drive wheel 20: Automatic transmission (mechanical stepped transmission)
26: Battery (power storage device)
28: Intermediate transmission member 30: Electric continuously variable transmission (electric continuously variable transmission)
50: Electronic control device (control device)
56: Engine start control unit 59: Threshold setting unit MG1: First rotating machine MG2: Second rotating machine

Claims (1)

And a differential mechanism having a first rotating element connected to the engine so that power can be transmitted, a second rotating element connected to the first rotating machine so as to transmit power, and a third rotating element connected to the intermediate transmission member. An electric continuously variable transmission that controls the differential state of the differential mechanism by controlling the operating state of the first rotating machine, and a power transmission path between the intermediate transmission member and the drive wheels. A mechanical stepped transmission part that constitutes a part and is selectively formed with a plurality of gear stages, a second rotating machine coupled to the intermediate transmission member so as to be capable of transmitting power, the first rotating machine, and the A control device for a vehicle including a power storage device that transmits and receives electric power to each of the second rotating machines,
During inertial running in which the operation of the engine is stopped, when the next downshift of the mechanical stepped transmission unit is executed, it is determined that the rotational speed of the intermediate transmission member becomes higher than a threshold value, and the current When it is determined that the next downshift is executed when deceleration traveling is continued at a deceleration, an engine start control unit that executes start control for starting the engine using the first rotating machine When,
And a threshold value setting unit that sets the threshold value to be smaller as the input power of the power storage device is lower.

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