JP6536498B2 - Driving mode switching control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a hybrid vehicle that can travel in a plurality of travel modes, and more particularly to a travel mode switching control device that travels while switching between the plurality of travel modes.

  (a) a mechanical transmission connected to the engine so as to be able to transmit power and to establish a plurality of gear stages having different power transmission states; and (b) connected to an output member of the mechanical transmission. It comprises a differential mechanism having a first rotating element, a second rotating element to which the first rotating machine is communicablely connected, and a third rotating element functioning as an output element, and the operation of the first rotating machine And (c) a second rotating machine coupled to the driving wheel so as to be able to transmit power, the electric differential portion in which the differential state of the differential mechanism is controlled by controlling the state; d) A hybrid vehicle capable of traveling in a plurality of traveling modes in which any one of the engine operation, non-operation and gear stages is different has been proposed. The device described in Patent Document 1 is one example, and in the case where the engine switches from inoperative EV (Electric Vehicle) traveling to HV (Hybrid Vehicle) traveling with change in gear, after changing the gear, the engine is not activated. It starts by ranking (refer to FIG. 9 of the same document).

International Publication No. 2013/114594

  However, in such a hybrid vehicle, multiple switching in which the traveling mode is continuously switched may occur in a short time, and the next traveling mode switching is performed after the first traveling mode switching is completed. The required switching time becomes long, and there is a possibility that the drivability performance such as the driving force response may be impaired. For example, in the case of the hybrid vehicle described in Patent Document 1, there is a possibility that the single motor travel of the EV is switched to HV high gear travel and further switching to HV low gear travel continuously by stepping on the accelerator pedal or the like. After starting the engine, it is necessary to switch to the low gear stage, and the switching required time becomes long.

  The present invention has been made against the background described above, and an object of the present invention is to make it possible to perform multiple switching in which the traveling mode is continuously switched in as short time as possible.

  According to the present invention, (a) a mechanical transmission unit connected to an engine so as to be able to transmit power and capable of establishing a plurality of gear stages having different power transmission states, and (b) an output member of the mechanical transmission unit A differential mechanism having a first rotary element connected to the first motor, a second rotary element to which the first rotary machine is power-transferably connected, and a third rotary element functioning as an output element; An electric differential unit in which the differential state of the differential mechanism is controlled by controlling the operating state of the rotating machine; and (c) a second rotating machine coupled to the drive wheels so as to be able to transmit power. (D) a hybrid vehicle capable of traveling in a plurality of traveling modes in which any of the engine operation, non-operation and gear stages are different; (e) a traveling mode in which the plurality of traveling modes are switched while traveling (F) predetermined traveling in the switching control device A switching determination unit that makes a switching determination of the traveling mode according to a driving mode switching condition, and (g) a first switching determination that changes the operation of the engine and changes the gear, by the switching determination unit In this case, while the traveling mode switching control is performed according to the first switching determination, the second switching determination is performed to switch to another traveling mode in which the change destination of the gear is different without changing the operation and non-operation of the engine And (h) if it is predicted that the second switching determination is to be performed by the multiple switching prediction unit, the change of the gear stage may be performed. While switching the operation and the non-operation of the engine in advance, if it is not predicted that the second switching judgment is to be made, the above-mentioned switching is performed prior to the switching of the operation and the non-operation of the engine And (i) the switching execution unit switches between operation and non-operation of the engine when it is predicted that the second switching determination is to be performed. Then, before performing the change of the gear, it is determined by the switching determination unit whether or not the second switching determination is actually made, and when the second switching determination is performed, It is characterized in that the change is omitted and the mode is switched to the other travel mode.

  In such a hybrid vehicle travel mode switching control device, when the first switching determination is performed, it is predicted whether or not the second switching determination is performed in the middle of the traveling mode switching control, and the second switching determination is performed. If it is predicted that the engine is switched on / off prior to the change of gear, while if the second switch judgment is not predicted, the gear is changed prior to the switch on / off of the engine Run. Then, if it is predicted that the second switching determination is to be performed, whether or not the second switching determination is actually performed before switching the gear stage after switching between the engine operation and non-operation. In order to switch to another travel mode based on the second switching judgment by omitting the change of the gear when the second switching judgment is performed, the switching to the other traveling mode is performed in a short time As a result, the driver performance such as the driving force response is improved.

FIG. 2 is a skeleton diagram for explaining a schematic configuration involved in traveling of a hybrid vehicle to which the present invention is applied, and is a diagram showing a main part of a control system together. It is a figure explaining the operation state of each part in several driving modes realizable with the hybrid vehicle of FIG. 1, and those driving modes. It is an example of the alignment chart of a mechanical transmission part and an electrical differential part at the time of single drive mode of EV. It is an example of the alignment chart of a mechanical transmission part and an electrical differential part at the time of both drive modes of EV. It is an example of the alignment chart of the mechanical transmission part at the time of series parallel high mode of HV, and an electrical differential part. It is an example of the alignment chart of the mechanical transmission part at the time of series parallel low mode of HV, and an electrical differential part. It is an example of the alignment chart of the mechanical transmission part at the time of parallel high mode of HV, and an electrical differential part. It is an example of the alignment chart of the mechanical transmission part in the time of parallel low mode of HV, and an electrical differential part. It is an example of the alignment chart of the mechanical transmission part at the time of the series mode of HV, and an electrical differential part. It is a figure explaining an example of a driving mode switching map in case there is no input-output restriction of a battery. It is a figure explaining an example of a driving mode switching map in case there is input-output restriction of a battery. It is a flowchart which demonstrates concretely the action | operation of the traveling mode switching control part which the electronic control unit of FIG. 1 has functionally. When step S3 of the flowchart of FIG. 12 is YES (affirmation) and is prior to the change of a gear stage, it is an example of the time chart explaining the change of the operation state of each part in the case of starting an engine. When step S3 of the flowchart of FIG. 12 is NO (negative), it is an example of the time chart explaining the change of the operating state of each part in the case of changing a gear stage prior to the start of an engine. It is the figure which illustrated the change of the alignment chart of time t1-t3 part in the time chart of FIG. It is the figure which illustrated the change of the alignment chart of time t3-t6 part in the time chart of FIG. FIG. 15 is a diagram illustrating changes in the alignment chart at time t4 to t8 in the time chart of FIG. 14;

  As a mechanical transmission unit, for example, a planetary gear type or parallel type capable of establishing a plurality of gear stages having different transmission ratios by a plurality of transmission engagement devices and capable of a cutoff state (neutral) for blocking power transmission. A stepped mechanical transmission such as a shaft type is suitable. Several gear stages can be defined to include both reduction gear stages (underdrive) with a gear ratio greater than 1 and acceleration gear stages (overdrive) with a gear ratio smaller than 1; Only one of the gear and the speed increasing gear may be included. The above-mentioned shutoff state can also be included in a plurality of gear stages.

  In the case of a planetary gear type mechanical transmission unit, for example, a single pinion type or a double pinion type single planetary gear mechanism is provided. The planetary gear mechanism is provided with three rotating elements of a sun gear, a carrier, and a ring gear, but in a collinear diagram in which their rotational speeds can be connected in a straight line, for example, the rotational elements having intermediate rotational speeds The engine is connected to (carrier of single pinion type planetary gear mechanism, ring gear of double pinion type planetary gear mechanism), one of the rotating elements on both sides functions as an output element, and the other can not selectively rotate via a brake By being fixed, a speed-up gear stage smaller than 1 is established. Further, by connecting any two of the three rotating elements selectively by means of a clutch, it is possible to establish a constant speed gear having a gear ratio of 1 at which the planetary gear mechanism rotates integrally. In the alignment chart, when the intermediate rotating element is used as an output element and the engine is connected to one of the rotating elements on both sides and the other can be selectively non-rotatably fixed by the brake, the gear ratio is 1 A larger reduction gear can be established.

  A single pinion type or double pinion type single planetary gear mechanism is preferably used as a differential mechanism of the electric differential portion. This planetary gear mechanism is provided with three rotating elements of a sun gear, a carrier, and a ring gear, but in a collinear diagram in which their rotational speeds can be connected in a straight line, for example, intermediate rotations have an intermediate rotational speed. The output member of the mechanical transmission unit is connected to the element (carrier of single pinion type planetary gear mechanism, ring gear of double pinion type planetary gear mechanism), and the first rotating machine and the driving wheel are connected to the rotating elements on both sides, The drive wheel may be connected to the intermediate rotating element. The rotating element connected to the drive wheel is an output element. These three rotating elements may always be differentially rotatable, but any two can be integrally connected by a clutch so that they can be integrally rotated according to the operating condition, or the first rotation It is also possible to limit differential rotation by allowing the brakes to stop rotation of the rotating elements to which the machine is connected.

  The rotating machine is a rotating electrical machine, specifically, a motor generator that can alternatively use the functions of an electric motor, a generator, or both. A generator may be employed as the first rotating machine and an electric motor may be employed as the second rotating machine, but when various operating conditions are assumed, both the first rotating machine and the second rotating machine are motor generators. It is desirable to use.

  The switching determination unit performs switching determination in accordance with traveling mode switching conditions such as a travel mode switching map or mode area map, which are determined using, for example, operating conditions such as an accelerator operation amount and vehicle speed as parameters. A plurality of types of traveling mode switching conditions can be determined according to the vehicle state such as the remaining amount of charge of the battery, or the basic traveling mode switching condition can be corrected according to the vehicle state. The present invention is preferably applied, for example, when switching to three or more travel modes in accordance with the vehicle load such as the accelerator operation amount. When the traveling mode switching condition is determined using a vehicle load such as an accelerator operation amount as a parameter, the multiple switching prediction unit performs the second switching determination based on, for example, a change rate (such as an accelerator change rate) of the vehicle load. It can be predicted whether or not. When the traveling mode is switched according to the vehicle speed, it is possible to predict whether or not the second switching determination is to be performed based on the change rate (acceleration / deceleration) of the vehicle speed, etc. Prediction modes are possible.

  The switching execution unit determines whether or not the second switching determination is actually made by the switching determination unit before performing the change of the gear in the traveling mode switching based on the first switching determination, and the second switching determination In this case, a jump switching unit is provided that switches to another traveling mode based on the second switching determination without changing the gear in the traveling mode switching based on the first switching determination. The other drive mode is a drive mode in which the shift destination of the gear is different but the shift destination of the gear is different as compared with the drive mode of the switching destination based on the first switching determination, and a new gear is changed The destination may be the gear before switching to the traveling mode according to the first switching determination, that is, the current gear or a new third gear.

  In the present invention, for example, (a) the mechanical transmission unit is engaged with a first gear in which one of a pair of shift engagement devices is engaged and the other is released, and the other is engaged. And, it is possible to establish the second gear in which one is released, and (b) in the hybrid vehicle, the engine is not in operation and the first gear is selected as the plurality of traveling modes. A first travel mode of the second gear, the second travel mode of the second gear, and the third travel mode of the first gear, the engine being in the operating state; The multiple switching prediction unit is configured to switch to the second traveling mode according to the first switching determination when the first switching determination to switch the first traveling mode to the second traveling mode is performed by the switching determination unit. Mode switching control is performed Among them, it predicts whether or not the second switching determination to switch to the third traveling mode is performed by the switching determination unit, and (d) the switching execution unit determines the second switching determination by the multiple switching prediction unit. If it is predicted that the second gear will be started, the engine will be started prior to the change to the second gear, but if it is not predicted that the second switching judgment will be made, the engine will be started prior to the start of the engine. Is configured to execute the change to the second gear. The third travel mode corresponds to another travel mode, and when switching to the third travel mode according to the second switching judgment, the third travel mode is established while maintaining the first gear without changing to the second gear. It can be done. Also, if the second switching determination is not predicted, the change to the second gear is performed prior to the start of the engine, but in the first travel mode, the engine is inoperative and the entire mechanical transmission section is stopped rotating. Therefore, engagement and release control of the pair of shift engagement devices can be performed in a short time without causing a shift shock.

  The hybrid vehicle is configured to include, for example, a connection device that connects and disconnects the engine and the first rotating machine. In that case, it is possible to use a traveling mode in which the operating state of the coupling device is different as the traveling mode, for example, by connecting the coupling device and disconnecting the mechanical transmission unit, the first rotating machine by the engine Can be driven to rotate and generate electric power, and the generated electric power can be used to execute a series mode in which the second rotating machine is driven by power running control. The connection device may be only a connection and disconnection device such as a clutch or the like, but may be connected via a transmission. The present invention is also applicable to a hybrid vehicle not equipped with such a connecting device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram illustrating a schematic configuration involved in traveling of a hybrid vehicle 10 to which the present invention is applied, and also shows a main part of a control system related to switching control of a traveling mode. In FIG. 1, hybrid vehicle 10 includes an engine 12, a first motor generator MG1, and a second motor generator MG2 that can be used as a drive source for traveling, and drive wheels (front wheels) via power transmission device 14. ) 16 to rotate. The engine 12 is an internal combustion engine that outputs power by burning a predetermined fuel, such as a gasoline engine or a diesel engine. The engine torque Te is controlled by the electronic control unit 80 controlling the operation state of the intake air amount, the fuel supply amount, the ignition timing and the like.

  The first motor generator MG1 and the second motor generator MG2 can be alternatively used as an electric motor and a generator. The first motor generator MG1 and the second motor generator MG2 are connected to the battery unit 20 through the power control unit 18 having an inverter unit, a smoothing capacitor, etc., and the power control unit 18 is controlled by the electronic control unit 80. As a result, the MG1 torque Tmg1 and the MG2 torque Tmg2, which are the torques (powering torque or regenerative torque) of the first motor generator MG1 and the second motor generator MG2, respectively, are controlled. The first motor generator MG1 is a first rotating machine, and the second motor generator MG2 is a second rotating machine.

  The power transmission device 14 is for a FF (front engine and front drive) type vehicle, and is housed together with the first motor generator MG1 and the second motor generator MG2 in the transaxle case 22 which is a non-rotational member. Power transmission device 14 transmits a first power transmission portion 24 for transmitting the output of at least one of engine 12 and first motor generator MG1 to driving wheel 16, and a second of transmitting the output of second motor generator MG2 to driving wheel 16. A power transmission unit 26 is provided. The first power transmission unit 24 includes a mechanical transmission unit 44 and an electric differential unit 46. The drive gear 30, which is an output member of the electric differential unit 46, includes a driven gear 30, a driven shaft 32, and a final gear. The power is transmitted to the differential device 38 through the differential ring gear 36 and distributed to the left and right drive wheels 16 through the pair of axles 40.

  The mechanical transmission unit 44 and the electric differential unit 46 are disposed coaxially with the input shaft 42 rotationally driven by the engine 12, and the mechanical transmission unit 44 includes a first planetary gear mechanism 48, a clutch C1, and the like. A brake B1 is provided. The first planetary gear mechanism 48 has, as three differentially rotatable elements, a single having a sun gear S1, a carrier CA1 supporting the pinion gear P1 rotatably and revolvably, and a ring gear R1 meshing with the sun gear S1 via the pinion gear P1. In the pinion type planetary gear mechanism, the carrier CA 1 is integrally connected to the input shaft 42 and functions as an input member of the mechanical transmission unit 44. The sun gear S1 is selectively coupled to the transaxle case 22 via the brake B1, and the sun gear S1 and the carrier CA1 are selectively coupled to one another via the clutch C1. . The ring gear R1 is connected to the electric differential 46 through a connecting member 45 that functions as an output member of the mechanical transmission 44.

  The clutch C1 and the brake B1 are both multiplate hydraulic friction engagement devices engaged and controlled by a hydraulic actuator, and the oil path switching valve of the hydraulic control circuit 52 and the hydraulic control valve are controlled by the electronic control unit 80. As a result, engagement and release control are performed in accordance with the C1 oil pressure Pc1 and B1 oil pressure Pb1 supplied from the oil pressure control circuit 52, respectively. Then, when both the clutch C1 and the brake B1 are released, the differential of the first planetary gear mechanism 48 is allowed, and the sun gear S1 freely rotates and can not take the reaction torque of the engine torque Te. The part 44 is brought into the neutral state (neutral state), and the power transmission is disabled. When both the clutch C1 and the brake B1 are engaged, the first planetary gear mechanism 48 is integrally brought into the rotation stop state, and the engine 12 is held in the rotation stop state via the input shaft 42. When the clutch C1 is engaged and the brake B1 is released, the first planetary gear mechanism 48 is integrally rotated, so that the rotational speed (engine rotational speed) Ne of the engine 12 is uniform, that is, the gear ratio At γ1 = 1, the ring gear R1 outputs the electric differential 46 through the connecting member 45. The gear ratio γ1 is the engine rotational speed Ne / the rotational speed of the ring gear R1. Further, when the clutch C1 is released and the brake B1 is engaged, the sun gear S1 is rotationally stopped, whereby the ring gear R1 is accelerated to rotate with respect to the input shaft 42, and the gear ratio γ1 <1. , And is output to the electric differential unit 46 via the connecting member 45. That is, the mechanical transmission unit 44 functions as a two-stage stepped transmission that can be switched between the low gear in the direct connection state (gear ratio γ1 = 1) and the high gear in the overdrive state (gear ratio γ1 <1). . The low gear corresponds to the first gear, and the high gear corresponds to the second gear. The clutch C1 and the brake B1 are gear shifting engagement devices.

  The alignment chart shown on the left side in FIGS. 3 to 9 relates to the mechanical transmission unit 44, and “ENG” is the engine 12. This alignment chart can connect the rotational speeds of the three rotating elements (sun gear S1, carrier CA1, ring gear R1) of the first planetary gear mechanism 48 in a straight line, and three vertical lines representing the respective rotating elements. The interval between Y1 and Y3 is determined according to the gear ratio of the first planetary gear mechanism 48 (the number of teeth of the sun gear S1 / the number of teeth of the ring gear R1).

  The electric differential portion 46 includes a second planetary gear mechanism 50. The second planetary gear mechanism 50 has, as three differentially rotatable elements, a single having a sun gear S2, a carrier CA2 supporting the pinion gear P2 rotatably and revolvably, and a ring gear R2 meshing with the sun gear S2 via the pinion gear P2. It is a pinion type planetary gear mechanism and functions as a differential mechanism that produces a differential action. The carrier CA 2 is integrally coupled to the coupling member 45 and functions as an input member of the electric differential portion 46. The sun gear S2 is integrally coupled to the rotor shaft 54 of the first motor generator MG1 for differential control. The ring gear R2 is integrally coupled to a drive gear 28 which functions as an output member of the electric differential 46. In this embodiment, the carrier CA2 is a first rotating element, the sun gear S2 is a second rotating element, the ring gear R2 is a third rotating element, and the ring gear R2 functions as an output element.

  The rotor shaft 54 of the first motor generator MG1 is selectively coupled to the input shaft 42 via the direct coupling clutch CS. The direct coupling clutch CS is a multi-plate type hydraulic friction engagement device engaged and controlled by a hydraulic actuator, and like the clutch C1 and the brake B1, the oil path switching valve and the hydraulic control valve of the hydraulic control circuit 52 By being controlled by the electronic control unit 80, engagement and release are controlled in accordance with the CS hydraulic pressure Pcs supplied from the hydraulic control circuit 52. The direct coupling clutch CS is a connecting and disconnecting device capable of connecting and disconnecting power transmission, and corresponds to a connecting device for connecting and disconnecting the engine 12 and the first motor generator MG1.

  When the direct coupling clutch CS is released, the differential of the second planetary gear mechanism 50 is allowed. In this state, second planetary gear mechanism 50 can function as a power distribution mechanism that distributes the power input to carrier CA2 to first motor generator MG1 and ring gear R2. That is, in addition to mechanical power transmission distributed to ring gear R2 in electric type differential unit 46, power generation is performed by rotationally driving first motor generator MG1 with power distributed to first motor generator MG1, The generated electric power can drive the second motor generator MG2 or charge the battery unit 20. The electric differential unit 46 controls the power control unit 18 by the electronic control unit 80 to control the operating state of the first motor generator MG1, whereby the gear ratio γ2 (= rotational speed of the carrier CA2 / ring gear R2 Functions as an electric continuously variable transmission that continuously controls the rotational speed). That is, the electric differential portion 46 includes the second planetary gear mechanism 50 as a differential mechanism, and the first motor generator as a differential control rotary machine coupled to the second planetary gear mechanism 50 so as to be able to transmit power. The electric transmission mechanism has an MG1 and an operation state of the first motor generator MG1 is controlled to control a differential state of the second planetary gear mechanism 50. Further, in a state in which the direct coupling clutch CS is engaged, the engine 12 and the first motor generator MG1 are coupled, so the first motor generator MG1 is rotationally driven by the power of the engine 12 to generate electric power It is possible to charge the battery unit 20 with electric power and drive the second motor generator MG2.

  The alignment chart shown on the right side in FIGS. 3 to 9 relates to the electric differential portion 46, and "OUT" is a drive gear 28 functioning as an output member. This alignment chart can connect the rotational speeds of the three rotating elements (sun gear S2, carrier CA2, ring gear R2) of the second planetary gear mechanism 50 in a straight line, and three vertical lines representing each of the rotating elements. The interval between Y4 and Y6 is determined according to the gear ratio of the second planetary gear mechanism 50 (the number of teeth of the sun gear S2 / the number of teeth of the ring gear R2). In this embodiment, the connecting member 45 is connected to a rotating element located at the middle of the alignment chart, that is, the carrier CA2 which is a rotating element having a rotating speed at which the rotational speed is intermediate in the differential state, It is supposed to be input. Further, the first motor generator MG1 and the driving wheel 16 are connected to one of the two rotating elements (sun gear S2 and ring gear R2) located on both sides of the alignment chart so as to be able to transmit power.

  In the first power transmission unit 24 configured as above, the power of the engine 12 and the power of the first motor generator MG1 are transmitted from the drive gear 28 to the driven gear 30. Therefore, the engine 12 and the first motor generator MG1 are coupled to the drive wheel 16 so as to be able to transmit power via the first power transmission unit 24. Further, since mechanical transmission portion 44 transmits power in the direct connection state or the overdrive state, the increase in torque of first motor generator MG1 is suppressed.

  In the first power transmission unit 24, since the mechanical transmission unit 44 and the electric differential unit 46 are connected in series, if the mechanical transmission unit 44 is changed in speed, the entire gear ratio γ0 of the first power transmission unit 24 (= Γ1 × γ2) is also changed. Therefore, the shift of the electric differential unit 46 is executed in accordance with the shift of the mechanical transmission unit 44 so that the change of the gear ratio γ0 of the first power transmission unit 24 is suppressed during the shift of the mechanical transmission unit 44. . For example, when the mechanical transmission 44 is upshifted from the low gear to the high gear, the electric differential 46 is simultaneously downshifted. Thereby, the first power transmission unit 24 can function as a so-called electric continuously variable transmission as a whole.

  The second power transmission unit 26 is integrally attached to the rotor shaft 56 of the second motor generator MG2 disposed in parallel to the input shaft 42 separately from the input shaft 42 and the rotor shaft 56 to mesh with the driven gear 30 A small diameter reduction gear 58 is provided. In the second power transmission unit 26, the power of the second motor generator MG2 is transmitted from the reduction gear 58 to the driven gear 30, and transmitted to the differential device 38 via the driven shaft 32, final gear 34, and differential ring gear 36. . That is, the second motor generator MG2 is connected to the drive wheel 16 so that power can be transmitted without the mechanical transmission portion 44 and the electric differential portion 46 of the first power transmission portion 24, and thus the reduction gear The degree of freedom in setting the reduction ratio by 58 is high, and the reduction ratio can be made large.

  The hybrid vehicle 10 includes an electronic control unit 80 as a controller that performs various controls related to traveling. The electronic control unit 80 is configured to include, for example, a so-called microcomputer provided with a CPU, a RAM, a ROM, an input / output interface and the like, and the CPU follows a program stored in advance in the ROM using a temporary storage function of the RAM. By performing signal processing, various controls of the hybrid vehicle 10 are executed. For example, the electronic control unit 80 executes output control of the engine 12, the first motor generator MG1, and the second motor generator MG2, switching control of a plurality of traveling modes, etc. The engine control, MG control, hydraulic control, etc. are divided.

  The electronic control unit 80 includes an engine rotation speed sensor 60 provided in the hybrid vehicle 10, an output rotation speed sensor 62, an MG1 rotation speed sensor 64 such as a resolver, an MG2 rotation speed sensor 66 such as a resolver, an accelerator operation amount sensor 68, Various signals based on values detected by shift position sensor 70, battery sensor 72, etc., that is, engine rotational speed Ne, output rotational speed Nout corresponding to rotational speed of driven gear 30 corresponding to vehicle speed V, rotational speed of first motor generator MG1 ( MG1 rotational speed) Nmg1, second motor generator MG2 rotational speed (MG2 rotational speed) Nmg2, accelerator pedal operation amount (acceleration operation amount) θacc, shift lever operation position Psh, battery unit 20 battery temperature THbat, battery charge Discharge current I at, such as the battery voltage Vbat, various information is supplied necessary for control. Further, the electronic control unit 80 outputs an engine control command signal Se, an MG control command signal Sm, a hydraulic control command signal Sp, etc. to the engine 12, the power control unit 18, the hydraulic control circuit 52 and the like. The electronic control unit 80 calculates the state of charge SOC of the battery unit 20 based on, for example, the battery charge / discharge current Ibat and the battery voltage Vbat.

  The electronic control unit 80 functionally includes a traveling mode switching control unit 82 that travels while switching a plurality of traveling modes in accordance with a predetermined switching condition. That is, the hybrid vehicle 10 of the present embodiment can travel in various travel modes shown in FIG. In FIG. 2, the EV mode is a control mode in which traveling is performed using at least one of the first motor generator MG1 and the second motor generator MG2 as a traveling drive source while the operation of the engine 12 is stopped. In the HV mode, at least the engine 12 is operated, and only the engine 12 is used as a drive source for traveling, or at least one of the first motor generator MG1 and the second motor generator MG2 is driven under certain conditions. It is a control mode which travels using as a drive source. Further, in the EV mode, two traveling modes of a single drive mode and a both drive mode are further defined, and in the HV mode, three traveling modes of a series parallel mode, a parallel mode, and a series mode are defined.

  FIG. 2 is a diagram for explaining the operating states of the clutch C1, the brake B1, the direct coupling clutch CS, and the motor generators MG1 and MG2 in each traveling mode. The "o" mark in the drawing of Fig. 2 means the engagement of the engagement device (C1, B1, CS), the blank means the release, and the "回 し" mark brings the engine 12 in the stop state. It means that either one is engaged at the time of combined use of the engine brake (it is also called Enbur). Also, "G" means that the motor generators MG1 and MG2 mainly function as a generator, and "M" mainly functions as an electric motor when driving the motor generators MG1 and MG2, and mainly as a generator when driven. It means to make it work. However, in the parallel mode of the HV, the motor generators MG1 and MG2 are operated as electric motors at a time of high load and the like in an assist manner, and the operation is stopped (free rotation state) at a low load.

  Specifically, in the single drive mode of the EV, the second motor generator MG2 is basically used as a drive source for traveling in a state in which the clutch C1, the brake B1 and the direct coupling clutch CS are all released. Run. FIG. 3 is an alignment chart in the EV single drive mode. By releasing the clutch C1 and the brake B1, the differential of the first planetary gear mechanism 48 is allowed, and the mechanical transmission unit 44 is in a neutral state (neutral state), and the power transmission is interrupted. When the mechanical transmission unit 44 is brought into the neutral state, the reaction force torque of the MG1 torque Tmg1 can not be obtained by the carrier CA2 connected to the ring gear R1, so the electric differential unit 46 is also brought into the neutral state. The transmission unit 24 is in a neutral state as a whole. In this state, the operation of the engine 12 is stopped, and the MG2 torque (powering torque) Tmg2 for traveling is output from the second motor generator MG2. During reverse travel, the second motor generator MG2 is reversely rotated with respect to forward travel. While the vehicle is traveling, the ring gear R2 connected to the drive gear 28 is rotated in conjunction with the rotation of the second motor generator MG2 (here, the rotation of the drive wheel 16 is also agreed). In the EV single drive mode, the first motor generator MG1 may idle without load, but the MG1 rotational speed Nmg1 is maintained at zero (rotation stop state) in order to reduce drag loss and the like in the first motor generator MG1. It is desirable to do. For example, the first motor generator MG1 can be made to function as a generator, and the MG1 rotational speed Nmg1 can be made zero by feedback control. Alternatively, d axis lock control (supplying only the d axis current in the dq axis coordinate system) is performed to supply current so that the rotation of the first motor generator MG1 is fixed, and the MG1 rotational speed Nmg1 is zeroed. Can also be maintained. Further, even if the MG1 torque Tmg1 is made zero, it is not necessary to add the MG1 torque Tmg1 when the MG1 rotational speed Nmg1 can be maintained at zero by the cogging torque of the first motor generator MG1. Since the first power transmission unit 24 is in the neutral state, the drive torque is not affected even if control is performed to maintain the MG1 rotational speed Nmg1 at zero.

  In the EV single drive mode, the ring gear R1 is also rotated integrally with the carrier CA2, but since the mechanical transmission unit 44 is in the neutral state, the engine 12 whose operation has been stopped is not rotated and is zero rotation. Stopped. Therefore, when the second motor generator MG2 is subjected to regeneration control (also referred to as power generation control) while traveling in the EV single drive mode, a large amount of regeneration can be taken. When the battery unit 20 is fully charged and regenerative energy can not be obtained during traveling in the EV single drive mode, it is conceivable to use an engine brake in combination. When the engine brake is used in combination, the brake B1 or the clutch C1 is engaged (see the combination of the engine shake in the EV single drive mode in FIG. 2). When the brake B1 or the clutch C1 is engaged, the engine 12 is brought into co-rotation and the engine brake is applied. By raising the MG1 rotational speed Nmg1 by power running control of the first motor generator MG1 or the like, the engine rotational speed Ne in the co-rotation state of the engine 12 can be increased.

  As described above, since the engine rotation speed Ne can be increased by engaging the brake B1 or the clutch C1, when the engine 12 is started from the EV mode, the brake B1 or the clutch C1 is engaged. As necessary, the engine rotation speed Ne is raised and ignited by powering control of the first motor generator MG1. At this time, the reaction force cancel torque is additionally output to the second motor generator MG2. When starting the engine 12 when the vehicle is stopped, the engine rotational speed Ne may be increased by pulling up the rotation of the carrier CA2 by the first motor generator MG1 with the brake B1 or the clutch C1 engaged. The engine rotational speed Ne may be increased by engaging the brake B1 or the clutch C1 after raising the rotation of the carrier CA2 by the first motor generator MG1. The direct coupling clutch CS may be engaged, and the rotational speed Ne of the engine 12 may be directly raised by the first motor generator MG1 to perform cranking.

  In FIG. 2, in both drive modes of EV ("Ne = 0"), both the clutch C1 and the brake B1 are engaged, and with the direct coupling clutch CS released, both the motor generators MG1 and MG2 are driven for traveling. Drive using as a source. FIG. 4 is a collinear diagram in this EV both-drive mode. By engaging the clutch C1 and the brake B1, the differential of the first planetary gear mechanism 48 is restricted, and the rotation of the sun gear S1 is stopped. Therefore, the rotation of the first planetary gear mechanism 48 is stopped. As a result, the engine 12 is stopped at zero rotation, and the rotation of the carrier CA2 connected to the ring gear R1 via the connection member 45 is also stopped. When the rotation of carrier CA2 is stopped, reaction force torque of MG1 torque Tmg1 can be obtained by carrier CA2, so the driving force is mechanically output from ring gear R2 by MG1 torque (here, powering torque in the reverse rotation direction) Tmg1. Can be transmitted to the drive wheel 16. That is, the operation of engine 12 is stopped, and MG1 torque Tmg1 and MG2 torque Tmg2 for traveling are output from first motor generator MG1 and second motor generator MG2, respectively. In this EV both drive mode, it is also possible to reversely rotate the first motor generator MG1 and the second motor generator MG2 together with respect to the time of forward movement to travel backward. In both drive modes of the EV, the direct transmission clutch CS is engaged and at least one of the clutch C1 and the brake B1 is engaged to hold the mechanical transmission unit 44 in the high gear or the low gear. It is also possible to travel using both of the motor generators MG1 and MG2 as a traveling drive source while rotating the engine 12 at a predetermined rotational speed.

  Even in the EV both drive mode, even when the required drive torque can be exceeded by only the second motor generator MG2, the operating point of the second motor generator MG2 represented by the MG2 rotational speed Nmg2 and the MG2 torque Tmg2 is the second motor generator If it is within the range where the efficiency of MG2 is deteriorated, in other words, if it is more efficient to use the first motor generator MG1 and the second motor generator MG2 together, the EV both-drive mode is selected. In the EV both drive mode, the required drive torque is shared by the first motor generator MG1 and the second motor generator MG2 based on the operating efficiency of the first motor generator MG1 and the second motor generator MG2.

  In FIG. 2, in the HV series parallel mode, the direct transmission clutch CS is released, and at least one of the clutch C1 and the brake B1 is engaged to hold the mechanical transmission unit 44 in the high gear or the low gear. By driving (operating) the engine 12 and performing powering control of the second motor generator MG2, the vehicle travels using both as a traveling drive source. FIG. 5 is an alignment chart in the case where the mechanical transmission 44 is in the high gear in the series parallel mode, and FIG. 6 is a collinear diagram in the case where the mechanical transmission 44 is in the low gear in the series parallel mode. FIG. The engagement of the clutch C1 or the brake B1 brings the mechanical transmission unit 44 into the non-neutral state, that is, the power transmission state, and the first motor generator MG1 handles the reaction force to the power of the engine 12 transmitted to the carrier CA2. Thus, part of the engine torque Te (engine direct delivery torque) can be mechanically output from the ring gear R2 and transmitted to the drive wheel 16. The first motor generator MG1 is regeneratively controlled and used as a generator, and can take charge of the reaction force. The generated electric power causes the second motor generator MG2 to perform powering control and outputs an MG2 torque Tmg2. In the series parallel mode, it is also possible to reversely rotate the second rotary machine MG2 with respect to forward movement and travel backward.

  Here, MG1 rotational speed Nmg1 becomes zero, and the power of engine 12 does not pass through an electric path (an electric power transmission path which is an electric path related to power exchange between first motor generator MG1 and second motor generator MG2). At the so-called mechanical point where all are mechanically transmitted to the drive gear 28, the theoretical value (theoretical transmission efficiency) of the power transmission efficiency (output power / input power) of the electric differential portion 46 is maximum It becomes "1" of. This mechanical point is in a state where the MG1 rotational speed Nmg1 of the electric differential portion 46 is zero (that is, the rotational speed of the sun gear S2 is zero) in the alignment charts of FIG. 5 and FIG. In the series parallel mode, the mechanical transmission unit 44 switches between the high gear stage and the low gear stage to provide two mechanical points, and the high parallel speed mode increases the mechanical point to the high vehicle speed side. Fast fuel consumption is improved. That is, as apparent from the traveling mode switching maps in FIGS. 10 and 11, the series parallel mode (series parallel high) in the high gear is selected on the relatively high vehicle speed side, and the high vehicle speed side is selected. The mechanical points are increased to improve high-speed fuel consumption.

  Further, in the series parallel mode, since the rotation speed of the carrier CA2 and further the engine rotation speed Ne can be controlled according to the MG1 rotation speed Nmg1, an engine operating point considering an optimum fuel consumption line of the engine 12, for example The engine 12 can also be operated at an engine operating point represented by Ne and the engine torque Te. In the series parallel mode, it is also possible to drive the second motor generator MG2 by adding the power from the battery unit 20 to the power generated by the first motor generator MG1.

  In FIG. 2, in the HV parallel mode, the mechanical transmission unit 44 is held at the high gear stage or the low gear stage by engaging the direct coupling clutch CS and engaging either the clutch C1 or the brake B1. Then, the engine 12 is operated (operated), and power running control of the first motor generator MG1 and / or the second motor generator MG2 is performed as necessary, whereby the vehicle travels using them as a traveling drive source. FIG. 7 is an alignment chart when the mechanical transmission unit 44 is set to the high gear in this parallel mode, and FIG. 8 is an alignment chart when the mechanical transmission unit 44 is set to the low gear in the parallel mode. In either case, only the engine 12 is used as a drive source for traveling, but by driving the first motor generator MG1 and / or the second motor generator MG2 as it is, it can be used as a drive source for traveling.

  In the parallel mode, the clutch C1 or the brake B1 is engaged in addition to the connection between the engine 12 and the first motor generator MG1 by the engagement of the direct coupling clutch CS, whereby the gear ratio γ1 of the mechanical transmission portion 44 is obtained. Accordingly, the entire gear ratio γ0 of the first power transmission unit 24 is fixed. Thus, the engine rotational speed Ne is uniquely determined with respect to the vehicle speed V (output rotational speed Nout). In this parallel mode, any power of engine 12, first motor generator MG1, and second motor generator MG2 can be mechanically transmitted to drive wheel 16. For example, in single drive in the parallel mode, the power of the second motor generator MG2 is transmitted to the drive wheels 16 in addition to the power of the engine 12 for traveling. At the time of both drive in the parallel mode, in addition to the power of the engine 12, the power of the first motor generator MG1 and the power of the second motor generator MG2 are transmitted to the drive wheels 16 to travel.

  The operating states of the respective engagement devices (C1, B1, CS) in the parallel mode are the same as in the EV both-drive mode (Ne free) shown in FIG. That is, the alignment charts of FIG. 7 and FIG. 8 become the same as the alignment charts of the EV both drive mode (Ne free) when the operation of the engine 12 is stopped. In this EV both drive mode (Ne free), the power transmitted from the first motor generator MG1 and the power from the second motor generator MG2 is transmitted to the drive wheels 16 as in the EV both drive mode (Ne = 0). Is possible. However, in the EV both drive mode (Ne free), the engine rotation speed Ne is uniquely determined according to the vehicle speed V during traveling, and thus the engine rotation speed Ne can not be made zero. It differs from the mode (Ne = 0).

  In FIG. 2, in the HV series mode, the first motor generator MG1 is rotationally driven by the operation of the engine 12 to generate electric power with the direct coupling clutch CS engaged and the clutch C1 and the brake B1 both released. By driving the second motor generator MG2 with the generated electric power, the vehicle travels using the second motor generator MG2 as a traveling drive source. FIG. 9 is an alignment chart in the series mode. By releasing both the clutch C1 and the brake B1, the differential of the first planetary gear mechanism 48 is allowed, and the mechanical transmission portion 44 is brought into the neutral state. Accordingly, the electric differential portion 46 is in the neutral state, and the first power transmission portion 24 is also in the neutral state. In addition, in the series mode, the direct coupling clutch CS is engaged, whereby the engine 12 and the first motor generator MG1 are coupled. Therefore, by operating the engine 12, the first motor generator MG1 can be rotationally driven to generate power. At this time, since the first power transmission unit 24 is in a neutral state, the engine torque Te is not mechanically transmitted to the drive wheel 16. The first motor generator MG1 is rotationally driven by the power of the engine 12, and the first motor generator MG1 is regeneratively controlled to generate electric power, whereby the second motor generator MG2 is driven by the generated electric power to drive the MG2 torque Tmg2 for traveling. Can be output. In the series mode, it is also possible to reversely rotate the second motor generator MG2 with respect to forward movement and travel backward.

  The traveling mode switching control unit 82 travels while switching a plurality of traveling modes shown in FIG. 2 and corresponds to a traveling mode switching control device. The traveling mode switching control unit 82 functionally includes a switching determination unit 84, a multiple switching prediction unit 86, and a switching execution unit 88. The switching determination unit 84 performs, for example, traveling mode switching shown in FIG. 10 and FIG. Switching determination of a plurality of traveling modes is performed according to traveling mode switching conditions such as a map. The travel mode switching map is previously stored in the storage unit of the electronic control unit 80, where the travel mode area to be selected using the vehicle load such as the accelerator operation amount θacc and the vehicle speed V as parameters is predetermined by experiment or simulation. It is done. FIG. 11 is a traveling mode switching map when input / output (charge / discharge) between the battery unit 20 and the motor generators MG1 and MG2 is restricted by the battery temperature THbat, the storage amount of charge SOC, and the like. FIG. 10 is a traveling mode switching map in the case where there is no such input / output restriction, that is, when the motor generator MG1, MG2 can perform torque assist or charge to the battery unit 20 by power generation relatively freely. is there.

  In the case of the traveling mode switching map of FIG. 11 in which there is input / output restriction of the battery unit 20, the series mode is selected when the vehicle load is positive (driving state) and relatively small and the vehicle speed is low. This series mode is also effective for preventing so-called rattling noise due to rattling between the second motor generator MG2 and the differential ring gear 36. Then, as the vehicle speed V increases, the mode is shifted to the parallel high mode or the series parallel high mode. Since the gear ratio γ0 is fixed in the parallel high mode, the engine 12 is easily deviated from the minimum fuel consumption operating point, and is set in a relatively narrow vehicle load region. In addition, when the load on the vehicle increases, transition to the series parallel low mode is made. This driving mode is effective when the driving force is prioritized. On the other hand, when the vehicle load is negative (in a driven state), the series mode is set. In the series mode, since the engine rotation speed Ne can be arbitrarily controlled at the same vehicle speed, it is possible to output an engine brake torque according to the driver's request. Further, since MG1 rotational speed Nmg1 and engine rotational speed Ne are the same, it is less likely to be restricted by engine rotational speed Ne due to the upper limit of MG1 rotational speed Nmg1 compared to other travel modes, and the absolute value of engine brake torque It can be enlarged.

  In the case of the traveling mode switching map of FIG. 10 in which there is no input / output restriction of the battery unit 20, the operation of the engine 12 is stopped and traveling is performed by the motor generators MG1 and MG2 in a region where the vehicle load is positive (driven) and low EV mode to be selected is selected. In the region where the vehicle load is small, the EV single drive mode in which only the second motor generator MG2 travels is selected, and in the relatively high load side, the EV dual drive mode in which both motor generators MG1 and MG2 travel is selected. When the EV mode is removed, the engine 12 is started to shift to the HV mode. However, in order to reduce the shock at the engine start, the EV mode is executed with a torque for reaction force compensation at the start remaining. As the HV mode, the series parallel high mode, the parallel high mode, and the series parallel low mode are selected as in FIG. 11. However, in the case of FIG. Then, the parallel low mode in which the torque assist (MG assist) by the motor generator MG1 and / or MG2 is performed is selected. At the time of kick down where the accelerator operation amount θacc increases rapidly, a parallel low mode may be implemented in which MG assist is given priority over the traveling mode switching map. On the other hand, even when the vehicle load is negative (driven state), the EV mode is selected in the low vehicle speed region, but since the vehicle drive torque is not generated, the EV mode region can be widened.

  The switching determination unit 84 determines, for example, whether or not the traveling mode selected according to the traveling mode switching map of FIG. 10 or FIG. 11 is different from the current traveling mode, and determines switching to the selected traveling mode if different. Do. Multiple switching prediction unit 86 and switching execution unit 88 perform signal processing according to steps S1 to S10 (hereinafter simply referred to as S1 to S10) in the flowchart of FIG. Execute travel mode switching control to switch to travel mode. S1 to S3 in the flowchart of FIG. 12 correspond to the multiple switching prediction unit 86, and S4 to S10 correspond to the switching execution unit 88. The switching execution unit 88 functionally includes a jump switching unit, and S5 and S7 correspond to the jump switching unit.

  In S1 of FIG. 12, it is determined whether the current travel mode is the EV single drive C1 on mode, that is, whether it is the travel mode in which the clutch C1 is engaged in the EV single drive combined braking mode in FIG. In the case of the EV single drive C1 on mode, there is a possibility of multiple switching in which the traveling mode is continuously switched when the vehicle load such as the accelerator operation amount θacc rapidly increases. For example, there is a possibility that the EV single drive C1 on mode is switched to the HV parallel high mode and the parallel low mode may be switched. However, when the traveling mode switching is performed in order, the entire traveling mode is switched The required time may be long, and the driving force responsiveness until the desired driving force can be obtained may be impaired. That is, in this S1, it is judged whether or not it is a traveling mode in which the driving force responsiveness may be impaired by multiple switching, and in this embodiment it is judged whether or not it is the EV single drive C1 on mode. Other travel modes may be set according to the mode switching condition. And if it is not the EV single drive C1 on mode, the process is ended as it is, but in the case of the EV single drive C1 on mode, S2 or less is executed. In the EV single drive C1 on mode, the engine 12 is in the non-operating state and the mechanical transmission unit 44 corresponds to the first traveling mode in the low gear, and in the parallel high mode in the HV, the engine 12 is in operation and the mechanical transmission unit 44 Is the second travel mode in the high gear, and the parallel low mode corresponds to the third travel mode in which the engine 12 is in operation and the mechanical transmission unit 44 is the low gear.

  In S2, it is determined whether the first switching determination to switch to the parallel high mode (second travel mode) of HV is made by the switching determination unit 84 or not. This parallel high mode is a traveling mode in which it is necessary to start and operate the engine 12 and switch the mechanical transmission unit 44 from low gear to high gear, as compared with the current EV single drive C1 on mode, for example When the accelerator pedal is depressed from the engine brake travel to reaccelerate, the first switching determination may be made. Then, if the first switching determination to switch to the parallel high mode is made, S3 is executed because there is a possibility of multiple switching, while if the first switching determination is not performed, the process ends as it is.

  In S3, while traveling mode switching control is performed to switch from the EV single drive C1 on mode to the parallel high mode according to the first switching determination, switching of the operation and non-operation of the engine 12 remains the same without changing the gear position change destination It is predicted whether or not the switching determination unit 84 makes a second switching determination to switch to the traveling mode, specifically the parallel low mode (third traveling mode). The parallel low mode is set, for example, in a region where the vehicle load is large as in the traveling mode switching map of FIG. 10, and may be selected prior to the traveling mode switching map during kickback where the accelerator operation amount θacc sharply increases. In the present embodiment, it is predicted that the second switching determination is highly likely to be performed when the change rate (the accelerator change rate) Δθ acc of the accelerator operation amount θ acc corresponding to the vehicle load is equal to or greater than a predetermined determination value. For example, a fixed value is determined as the determination value, but it is also possible to variably set the operating condition such as the vehicle speed V as a parameter. Then, if it is predicted that the second switching determination is likely to be performed, S4 and subsequent steps are executed, and if the second switching determination is unlikely to be performed, S8 and subsequent steps are executed.

  In S4, in order to switch from the EV single drive C1 on mode to the parallel high mode, the MG1 rotational speed Nmg1 is increased by the powering control of the first motor generator MG1, and the mechanical transmission unit 44 in the low gear state is The engine rotation speed Ne is raised and cranked, and when the predetermined start rotation speed is reached, start control such as fuel injection and ignition is performed to start the engine 12. The next S5 is executed after the engine 12 is started and reaches, for example, the idle rotational speed, and the switching determination unit 84 determines whether the second switching determination to switch to the parallel low mode has actually been performed. . When the second switching determination is actually performed, S7 is performed, and when the second switching determination is not performed, S6 is performed. In S6, since it is sufficient to continue the traveling mode switching control to the parallel high mode as it is, the clutch C1 is released and clutch-to-clutch shift control for engaging the brake B1 is performed to change from low gear to high gear (shift) At the same time, synchronous control is performed so that the engine rotation speed Ne and the MG1 rotation speed Nmg1 become substantially the same, and the direct coupling clutch CS is engaged. The synchronous control is performed by controlling the MG1 torque Tmg1 so that the MG1 rotational speed Nmg1 becomes a predetermined synchronous rotational speed determined by the vehicle speed V, the MG2 rotational speed Nmg2, the gear ratio γ1 and the like. On the other hand, in S7, since it is not necessary to change the gear of the mechanical transmission unit 44, synchronous control is performed so that the engine rotational speed Ne and the MG1 rotational speed Nmg1 become substantially the same in the low gear stage. Engage.

  FIG. 13 is an example of a time chart for explaining the change of the operating state of each part when the determination of S3 of the above-mentioned flowchart is YES and S4 and subsequent steps are executed and the engine 12 is started prior to the change of gear. When the mode is switched to the parallel high mode by S6, the alternate long and short dash line is the case where the traveling mode jump switching to the parallel low mode is performed in S7. Time t1 in FIG. 13 is the time when the accelerator pedal is depressed for reacceleration during engine brake traveling in the EV single drive C1 on mode. A time t2 is a time when the MG1 torque Tmg1 is made zero and the engine rotation speed Ne becomes substantially zero. The time t3 is the time when the first switching judgment to switch from the EV single drive C1 on mode to the parallel high mode is made, that is, the time when the judgment of S2 becomes YES, the judgment of S3 is also YES and S4 is executed immediately It is the time when cranking of the engine 12 was started. Time t4 is a time when the engine 12 is started by start control such as fuel injection. The solid line after time t5 is the case where the determination in S5 is NO and S6 is executed, and time t5 is the time when the clutch-to-clutch shift to change from the low gear to the high gear is started. Time t6 is the time when clutch-to-clutch shifting is completed and high gear is established, and synchronous control of engine rotational speed Ne and MG1 rotational speed Nmg1 is completed, which is the time when engagement control of direct coupling clutch CS is started is there. Time t7 is a time when the direct coupling clutch CS is completely engaged and the parallel high mode is established.

  FIGS. 15 and 16 illustrate the changes in the operating state of each part in the time chart shown by the solid line in FIG. FIG. 15 (a) shows the state during engine brake travel before time t1, that is, under the powering control of the first motor generator MG1, the engine rotational speed Ne is a predetermined rotational speed via the mechanical transmission unit 44 of low gear. It is pulled up to the point where the engine brake is applied. In (b) of FIG. 15, the engine rotational speed Ne is reduced to approximately 0 with the depression operation of the accelerator pedal, and the engine braking force becomes approximately 0, and the time t2 to drive and travel by the second motor generator MG2 It is in the state of t3. (C) of FIG. 16 shows a state of time t3 to t4 during which the engine rotation speed Ne is raised by cranking by the power-running control of the first motor generator MG1, and (d) shows that the high gear is established by the clutch-to-clutch shift. At the same time, the synchronous control of the engine rotation speed Ne and the MG1 rotation speed Nmg1 is performed and it is in the state of the time t6 which is substantially synchronized.

  The dashed-dotted line after time t5 in FIG. 13 is the case where the determination in S5 in FIG. 12 is YES and S7 is executed, and there is no need to change the gear, so engine rotation speed Ne and MG1 rotation speed Nmg1 Synchronous control is performed, and engagement control of the direct coupling clutch CS is performed.

  If it is determined in S3 in FIG. 12 that the possibility of the second switching determination is low, S8 and subsequent steps are executed, and travel mode switching control from the EV single drive C1 on mode to the parallel high mode is simply performed. . That is, first, at S8, the clutch C1 is released and the brake B1 is engaged to execute a clutch-to-clutch shift that changes from the low gear to the high gear. In this case, as shown in (b) of FIG. 15, the engine rotational speed Ne is substantially zero, and the entire mechanical transmission unit 44 is in the rotation stop state, so clutch-to-clutch shift is shortened without producing shift shock. It can be done in time. In the next S9, the engine rotation speed Ne is raised and cranked by raising the MG1 rotation speed Nmg1 by the powering control of the first motor generator MG1 as in the S4 and the fuel injection is performed when the predetermined start rotation speed is reached. And start control such as ignition to start the engine 12. Further, in S10, synchronous control is performed so that the engine rotation speed Ne and the MG1 rotation speed Nmg1 become substantially the same, and the direct coupling clutch CS is engaged.

  FIG. 14 is an example of a time chart illustrating a change in the operating state of each part when the gear is changed prior to the start of the engine 12 after the step S8 and the steps subsequent to the step S3 are executed until time t3. Is the same as FIG. The time t3 is the time when the first switching determination to switch from the EV single drive C1 on mode to the parallel high mode is made, that is, the time when the determination of S2 becomes YES, by executing S8 following S3. It is the time when the clutch-to-clutch shift that changes from the low gear to the high gear is started. Time t4 is the time when the clutch-to-clutch shift is completed, and the clutch-to-clutch shift is performed without any change in the engine rotational speed Ne or the like. Time t5 is a time when cranking of the engine 12 is started by execution of S9, and time t6 is a time when the engine 12 is started by start control such as fuel injection. A time t7 is a time when synchronous control of the engine rotational speed Ne and the MG1 rotational speed Nmg1 is started by execution of S10, and a time t8 is a time when engagement control of the direct coupling clutch CS is started after synchronization. Time t9 is a time when the direct coupling clutch CS is completely engaged and the parallel high mode is established.

  FIG. 17 exemplifies the change of the operation state of each part after time t3 in the time chart of FIG. 14 as an alignment chart, and is the same as FIG. 15 until time t3. FIG. 17 (c) shows the state at time t4 when the high gear is established by the clutch-to-clutch shift, and FIG. 17 (d) shows that the engine rotational speed Ne is raised by cranking by the powering control of the first motor generator MG1. It is a state of time t5 to t6. (e) is a state of time t8 at which the synchronous control of the engine rotation speed Ne and the MG1 rotation speed Nmg1 is performed and substantially synchronized.

  Thus, in the hybrid vehicle 10 of the present embodiment, when the first switching determination to switch from the EV single drive C1 on mode to the parallel high mode is performed (the determination in S2 is YES), traveling is performed according to the first switching determination. During the traveling mode switching control to switch the mode, it is predicted whether or not the second switching determination to switch to the parallel low mode is performed (S3). When it is determined that the second switching determination is likely to be performed, S4 and subsequent steps are executed to start the engine 12 prior to the change of the gear, while the second switching determination may be performed. If it is determined that the engine speed is low, step S8 and subsequent steps are executed to change the gear prior to the start of the engine 12. If it is determined that the second switching determination is likely to be performed and S4 and subsequent steps are executed, it is determined whether the second switching determination is actually performed before the gear position change is performed (S5) When the second switching judgment is made, the direct clutch is engaged in S7 without changing the gear and the parallel low mode is established as it is, so that switching to the parallel low mode is performed in a short time As a result, driveability such as driving force response is improved.

  On the other hand, if it is determined that the possibility of the second switching determination is low and S8 and subsequent steps are executed, clutch-to-clutch shift is performed to change from low gear to high gear prior to starting engine 12. Since the speed Ne is approximately 0 and the entire mechanical transmission unit 44 is in the rotation stop state, clutch-to-clutch shift can be performed in a short time without causing shift shock.

  In the above embodiment, the gear train of the connection relationship is such that the second motor generator MG2 is disposed on an axis different from the axis of the first power transmission unit 24, but, for example, the second motor generator MG2 The gear train may be in a connection relationship such as being disposed on the same axial center as the axial center of the first power transmission unit 24.

  Further, although the power transmission device 14 suitably used for the FF type hybrid vehicle 10 has been described as an example, the present invention can also be applied to the FR type, RR type, and four-wheel drive type hybrid vehicles. The second motor generator MG2 can also be applied to a four-wheel drive hybrid vehicle in which drive wheels (rear wheels) different from the drive wheels 16 driven by the engine 12 are driven.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, this is merely an embodiment, and the present invention may be implemented in variously modified and / or improved modes based on the knowledge of those skilled in the art. Can.

  Reference Signs List 10: hybrid vehicle 12: engine 16: drive wheel 44: mechanical transmission unit 45: connection member (output member) 46: electrical differential unit 50: second planetary gear mechanism (differential mechanism) 80: electronic control unit 82 Driving mode switching control unit (traveling mode switching control device) 84: Switching determination unit 86: Multiple switching prediction unit 88: Switching execution unit CA2: Carrier (first rotation element) S2: sun gear (second rotation element) R2: ring gear (Third rotating element) MG1: first motor generator (first rotating machine) MG2: second motor generator (second rotating machine)

Claims (1)

A mechanical transmission unit that is coupled to the engine so as to be able to transmit power and that can establish a plurality of gear stages having different power transmission states,
A difference having a first rotating element connected to an output member of the mechanical transmission unit, a second rotating element to which the first rotating machine is connected for power transmission, and a third rotating element functioning as an output element An electric differential unit including a moving mechanism, wherein a differential state of the differential mechanism is controlled by controlling an operating state of the first rotating machine;
A second rotating machine coupled to the drive wheels so as to be able to transmit power;
A hybrid vehicle capable of traveling in a plurality of traveling modes different in any of the engine operation, non-operation, and gear stages, wherein the traveling mode switching control device travels while switching the plurality of traveling modes;
A switching determination unit that determines switching of the traveling mode in accordance with a predetermined traveling mode switching condition;
When the first switching determination for changing the gear position and switching between the operation and non-operation of the engine is performed by the switching determination unit, the traveling mode switching control is performed according to the first switching determination. A multiple switching prediction unit that predicts whether or not a second switching determination is performed by the switching determination unit to switch to another traveling mode in which the change destination of the gear is different while switching between engine operation and non-operation remains unchanged;
If it is predicted that the second switching judgment is to be performed by the multiple switching prediction unit, it is predicted that the second switching judgment is performed while switching the operation and non-operation of the engine prior to the change of the gear. If not, the switch execution unit executes the change of the gear stage prior to switching the engine operation and non-operation, and
And, if it is predicted that the second switching determination is to be performed, the switching execution unit may switch the operation and non-operation of the engine before performing the change of the gear stage. It is determined whether or not the second switching determination is actually performed by the switching determination unit, and when the second switching determination is performed, the change of the gear is omitted and switching to the other traveling mode is performed. A driving mode switching control device for hybrid vehicles.

Images