JP6547699B2 - 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) The first rotation element is selectively stopped by the transmission brake, the second rotation element is movably coupled to the engine, and the third rotation element is coupled to the output member. A planetary gear type stepped transmission unit in which any two of the rotating element to the third rotating element are selectively connected by the transmission clutch; (b) a fourth connected to the output member of the stepped transmission unit A differential mechanism including a rotating element, a fifth rotating element to which the first rotating machine is communicablely connected, and a sixth rotating element functioning as an output element, wherein the operating state of the first rotating machine is (D) an electric differential unit in which a differential state of the differential mechanism is controlled by being controlled; (c) a second rotating machine coupled to the drive wheels so as to be able to transmit power; An EV (Electric Vehicle) traveling mode that travels with the engine stopped. , And HV (Hybrid Vehicle) hybrid vehicle capable of traveling modes traveling in a state of being operated the engine has been proposed (see Patent Document 1).

International Publication No. 2013/114594

  By the way, although not yet known, it is conceivable to provide a direct engagement portion for selectively connecting the engine and the first rotating machine in the above-mentioned hybrid vehicle. In that case, the types of travel modes are increased and options are increased by engaging or releasing the direct coupling engagement portion, and both the first and second rotating machines are used for traveling in the EV travel mode. Also for both drive modes that can be used and driven as a drive source, a first engagement pattern in which one of the shift brake and the shift clutch is engaged and the other is released and the direct engagement portion is engaged Although it is possible to engage both the transmission brake and the transmission clutch and release the direct connection part, the second engagement pattern becomes a problem.

  The present invention has been made against the background described above, and the object of the present invention is a hybrid vehicle in which the engine and the first rotary machine can be connected by the direct coupling engagement portion, and a plurality of types of engagement patterns are different. The appropriate engagement pattern is to be selected from among the two EV drive modes.

  According to the present invention, (a) the first rotation element is selectively stopped by the transmission brake, the second rotation element is connected to the engine in a power transmittable manner, and the third rotation element is connected to the output member. A planetary gear type stepped transmission unit in which any two of the first to third rotating elements are selectively connected by a transmission clutch; and (b) connected to the output member of the stepped transmission unit A differential mechanism having a fourth rotating element as described above, a fifth rotating element to which the first rotating machine is communicablely connected, and a sixth rotating element functioning as an output element, the first rotating machine And an electric differential unit in which the differential state of the differential mechanism is controlled by controlling an operation state of the motor, and (c) a second rotating machine coupled to the drive wheels so as to be able to transmit power. (D) EV driving mode in which the vehicle is driven with the operation of the engine stopped And a hybrid vehicle capable of an HV travel mode capable of traveling in a state where the engine is operated; (e) a travel mode switching control device for traveling while switching between the EV travel mode and the HV travel mode; The hybrid vehicle is provided with a direct connection portion capable of selectively connecting the engine and the first rotating machine, and (g) engaging one of the shift brake and the shift clutch as the EV travel mode. A first engagement capable of traveling using both the first rotating machine and the second rotating machine as a traveling drive source in a state where the other is released and the other is released and the direct coupling engagement portion is engaged. In the state in which both drive modes of the joint pattern, the shift brake and the shift clutch are engaged together and the direct engagement portion is released, the first rotary machine And both drive modes of the second engagement pattern that can travel using both of the second rotating machine as a drive source for traveling, the shift brake, the shift clutch, and the direct coupling engagement portion. In the released state, it is possible to use a single drive mode in which only the second rotating machine is used as a drive source for traveling, while (h) the single drive mode, both drive in accordance with a predetermined traveling mode switching condition. A switching determination unit that determines switching between a plurality of driving modes including the mode and the HV traveling mode, and (i) a first switching determination is made by the switching determination unit to switch from the single drive mode to the both drive modes In this case, the HV switching prediction unit predicts whether or not the second switching determination unit switches to the HV traveling mode after switching to the both drive modes by the switching determination unit; (j) The HV switching prediction unit is characterized in that, when it is predicted that the second switching determination is to be performed, the switching execution unit switches the driving mode to both drive modes of the first engagement pattern.

  In such a hybrid vehicle travel mode switching control device, if the first switching determination to switch from the single drive mode to both drive modes is performed, whether the second switching determination to switch to the HV traveling mode is further performed In order to switch to both drive modes of the first engagement pattern when the second switching judgment is predicted, the engine is rotated together with the vehicle speed according to the vehicle speed, and the engine is swiftly transitioned to the HV travel mode. As compared with both drive modes of the second engagement pattern in which the engine can be stopped, the switching time to the HV travel mode is shortened and excellent drive force response performance can be obtained.

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 (Ne = 0) 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 (Ne free high gear) 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 (Ne free low gear) mode 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 in FIG. 14 is YES (affirmative) and is switched to both drive (Ne free low gear) mode of the first engagement pattern, this is an example of a time chart for explaining changes in the operating state of each part. 15 is an example of a time chart for explaining changes in operation states of the respective parts when step S3 of the flowchart of FIG. 14 is NO (negative) and switching to the both drive (Ne = 0) mode of the second engagement pattern.

  The planetary gear type stepped transmission unit is configured to include, for example, a single pinion type or a double pinion type single planetary gear mechanism. 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 a carrier of a single pinion type planetary gear mechanism, and a ring gear of a double pinion type planetary gear mechanism, one of the rotating elements on both sides is connected to an output member, and the other is selectively rotated via a transmission brake. Impossible fixed. In this case, it is possible to establish an acceleration gear (overdrive) whose gear ratio is smaller than 1 and to selectively connect any two of the three rotating elements by means of a transmission clutch, thereby achieving a planetary gear. A constant speed gear having a gear ratio of 1 at which the mechanism rotates integrally can be established. Also, for example, when the rotational element located at the middle of the alignment chart is connected to the output member, the engine is connected to one of the rotational elements on both sides, and the other can be selectively fixed non-rotatably by the transmission brake. The reduction gear (underdrive) having a gear ratio larger than 1 can be established.

  When the gearshift clutch and the brake are both released, the stepped transmission unit is in a neutral state (neutral state) where power transmission is interrupted. When the clutch and the brake are both engaged, the entire gear including the engine is included. It will be in the stationary state where the rotation of each rotating element is stopped. As the transmission clutch and the brake, a friction engagement type clutch and a brake are suitably used, but a mesh type clutch and a brake, a belt type brake and the like can also be adopted.

  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, and as the first rotating machine and the second rotating machine, a motor generator that can alternatively use the functions of an electric motor and a generator is suitable. An electric motor can also be adopted.

  The direct connection part capable of selectively connecting the engine and the first rotating machine is a connecting / disconnecting device capable of connecting and disconnecting power transmission, and a friction engagement type clutch is suitably used, but a mesh type clutch is adopted It can also be done. The engine and the first rotating machine may be connected via a transmission gear or the like as required. That is, the direct coupling engagement portion is disposed in parallel to the planetary gear type stepped transmission and the electric differential, and the planetary gear type stepped transmission and the electric differential are What is necessary is just to be able to connect the engine and the first rotating machine so as to be able to transmit power without intervention.

  The switching determination unit makes switching determination in accordance with traveling mode switching conditions such as a traveling mode switching map or driving mode area map, which is determined using, for example, operating conditions such as an accelerator operation amount and vehicle speed as parameters. A plurality of types of travel mode switching conditions can be determined according to the vehicle state such as the remaining amount of charge of the battery, or the basic travel mode switching condition can be corrected according to the vehicle state. The present invention is preferably applied, for example, when the EV single drive mode is switched from the EV single drive mode to the EV dual drive mode in accordance with the vehicle load such as the accelerator operation amount, and is further switched to the HV travel mode. In addition, even in the EV travel mode region, the present invention is preferably applied to the case where the travel mode switching condition is determined so as to switch to the HV travel mode when the state of charge SOC of the battery is small. That is, the HV switching prediction unit predicts, for example, whether or not the second switching determination is to be performed based on the change rate of the vehicle load (accelerator change rate etc.), or the second switching determination based on the state of charge SOC. It can be predicted whether it will be done or not. In addition, when the traveling mode is switched according to the vehicle speed, whether or not the second switching determination is to be made can be predicted based on the rate of change (acceleration / deceleration) of the vehicle speed. Various prediction modes are possible.

  For example, when it is predicted that the second switching determination is to be performed, the switching execution unit switches to both drive modes of the first engagement pattern, and when it is not predicted that the second switching determination is to be performed, It is configured to switch to both drive modes. In the second engagement pattern, each rotational element of the stepped transmission unit including the engine is stopped rotating, so that excellent fuel efficiency performance can be obtained as compared to the first engagement pattern in which the engine is co-rotated. On the other hand, it is not predicted that the second switching judgment is to be made, for example, it is desirable to set both drive modes of the first engagement pattern in an operation state requiring engine braking such as downhill because engine braking does not work. The engagement pattern of both drive modes is appropriately determined. Even when the state of charge SOC is large, the regeneration control of the first rotating machine and the second rotating machine is limited, and there is a possibility that the braking action by the regenerative torque may not be obtained during driven driving. It is desirable to use both drive modes of one engagement pattern. That is, when it is not predicted that the second switching determination is to be performed, when it is determined that the engine brake is necessary based on the driving state of the vehicle, the storage SOC, etc., both drive modes of the first engagement pattern are selected. Basically, it is desirable to use both drive modes of the second engagement pattern except the above. Even when there is no possibility that the second switching determination will be made, for example, when the EV request switch is turned ON to travel only in the EV travel mode, switching to both drive modes of the second engagement pattern may be performed. Since the engine is rotated along with the first engagement pattern in both drive modes, the rotational resistance due to the pumping action is suppressed with a decompression device or the like when driving without the need for engine braking. Is desirable.

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. In this embodiment, the sun gear S1 is a first rotation element, the carrier CA1 is a second rotation element, the ring gear R1 is a third rotation element, the clutch C1 is a transmission clutch, and the brake B1 is a transmission brake.

  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 in a stationary state in which the rotation is integrally stopped, and the engine 12 is also held in the rotational 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 is a two-step stepped transmission unit which is switched to 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 alignment chart shown on the left side in FIGS. 3 to 11 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). In this embodiment, the input shaft 42 is connected to a rotating element positioned in the middle of the alignment chart, that is, the carrier CA1 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. In addition, one of the two rotary elements (sun gear S1 and ring gear R1) (ring gear R1 in the embodiment) located on both sides of the alignment chart is connected to the connecting member 45 which is an output member, and the other (sun gear S1 in the embodiment) Is selectively non-rotatably fixed via the brake B1.

  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 fourth rotation element, the sun gear S2 is a fifth rotation element, the ring gear R2 is a sixth rotation 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 is disposed in parallel to the mechanical transmission unit 44 and the electric differential unit 46, and the mechanical transmission unit 44 and the electric transmission unit 44 are electrically connected. It corresponds to a direct coupling engagement portion which can connect the engine 12 and the first motor generator MG1 so as to allow power transmission without interposing the differential portion 46.

  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 11 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, Output rotational speed Nout, which is the rotational speed of driven gear 30 corresponding to engine rotational speed Ne and vehicle speed V, from shift position sensor 70, EV request switch 72, battery sensor 74 etc., 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 (accelerator operation amount) θacc, shift lever operation position Psh, EV request Sev, battery unit 20 battery temperature THbat, battery Charge and discharge Ibat, a 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. EV request switch 72 is disposed on an instrument panel or the like in the vicinity of the driver's seat, and is operated by an ON operation (such as a pressing operation) by the driver, in an EV travel mode in which only motor generators MG1 and MG2 travel as a drive source. A signal representing the EV request Sev requiring traveling is output to the electronic control unit 80.

  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 travel mode is a control mode in which travel is performed using at least one of the first motor generator MG1 and the second motor generator MG2 as a travel drive source in a state where the operation of the engine 12 is stopped. In the HV traveling mode, at least the engine 12 is operated, and only the engine 12 is used as a driving source for traveling, or at least one of the first motor generator MG1 and the second motor generator MG2 is traveled under certain conditions. It is a control mode which travels using it as a drive source. And in EV driving mode, two driving modes of single drive mode and both drive modes are further defined, and in HV traveling mode, three driving modes of series parallel mode, parallel mode, and series mode are defined. There is.

  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 "状態" 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). “G” means that the motor generators MG1 and MG2 mainly function as a generator, and “M” mainly causes the motor generators MG1 and MG2 to function as an electric motor during driving travel, and mainly during driven traveling. It means to function as a generator. 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 be idled without load, but the MG1 rotational speed Nmg1 is maintained at 0 (rotation stop state) 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 function as a generator, and the MG1 rotational speed Nmg1 can be set to 0 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 MG1 rotational speed Nmg1 is set to 0 Can also be maintained. Further, even if the MG1 torque Tmg1 is set to 0, when the MG1 rotational speed Nmg1 can be maintained at 0 by the cogging torque of the first motor generator MG1, it is not necessary to add the MG1 torque Tmg1. Note that, even if control is performed to maintain the MG1 rotational speed Nmg1 at 0, since the first power transmission unit 24 is in the neutral state, the drive torque is not affected.

  In the EV single drive mode, the ring gear R1 is also brought together 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 taken together and is in the stopped state. Become. 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 co-rotated 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, it is possible to increase the engine rotational speed Ne in the state in which the engine 12 is brought in, that is, the engine brake torque.

  As described above, since the engine rotation speed Ne can be increased by engaging the brake B1 or the clutch C1, when starting the engine 12 from the EV travel mode, the brake B1 or the clutch C1 is engaged. The engine rotation speed Ne is raised and ignited by the powering control of the first motor generator MG1 as necessary. 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 (Ne = 0) of the EV, both the clutch C1 and the brake B1 are engaged and the motor generator MG1 and MG2 are both used as a drive source for traveling with the direct coupling clutch CS released. Use and drive. FIG. 4 is an alignment chart in the EV both-drive (Ne = 0) 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 first planetary gear mechanism 48 is in a stationary state in which the rotation of any of the rotating elements is stopped. As a result, the engine 12 is stopped, 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 can be stopped, and MG1 torque Tmg1 and MG2 torque Tmg2 for traveling can be output from first motor generator MG1 and second motor generator MG2, respectively. In the EV both-drive (Ne = 0) mode, it is also possible to reversely rotate both the first motor generator MG1 and the second motor generator MG2 with respect to forward movement and travel backward. Both drive (Ne = 0) modes are both drive modes of the second engagement pattern.

  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 stage or the low gear stage. It is also possible to travel using both of the motor generators MG1 and MG2 as a traveling drive source while rotating 12 at a predetermined rotational speed. FIG. 5 is a collinear diagram of the both drive (Ne free high gear) mode in which the direct transmission clutch CS and the brake B1 are engaged to hold the mechanical transmission unit 44 in the high gear, and FIG. 6 is a direct connection clutch CS and clutch C1. FIG. 6 is an alignment chart of a dual drive (Ne free low gear) mode in which the mechanical transmission unit 44 is held in the low gear step by engaging the two gear wheels. In these two drive (Ne free) modes, the engine 12 is rotated in accordance with the vehicle speed V, that is, the MG2 rotational speed Nmg2, so that the engine brake is generated by rotational resistance due to the pumping action of the engine 12 during driven traveling. It can be done. During drive travel, it is desirable to suppress the engine brake with a decompression device or the like. The decompression device can control, for example, the lift amount of the intake and exhaust valves, and by increasing the lift amount in the compression stroke to open it, the pressure increase in the cylinder is suppressed and the pumping action is reduced. Other decompression devices can also be used. The two drive (Ne free) modes are both drive modes of the first engagement pattern. In this embodiment, both drive (Ne free high gear) mode for engaging the brake B1 and both drive (Ne for engaging the clutch C1 Although two types of both drive (Ne free) modes of the free low gear mode can be selected, it is sufficient to set either one of both drive (Ne free) modes.

  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. 7 is an alignment chart in the case where the mechanical transmission 44 is in the high gear in the series parallel mode, and FIG. 8 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 motor generator MG2 with respect to forward movement and travel backward.

  Here, MG1 rotational speed Nmg1 becomes 0, and the power of engine 12 does not pass through the electric path (an electric power transmission path which is an electric path involved in the transfer of power of 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 0 (that is, the rotational speed of the sun gear S2 is 0) in the alignment chart of FIGS. 7 and 8. 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. 12 and 13, 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 with high torque 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. 9 is an alignment chart when the mechanical transmission unit 44 is set to the high gear in this parallel mode, and FIG. 10 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. Note that the operating state of each engagement device (C1, B1, CS) in the parallel mode is the same as in the EV both drive (Ne free) mode, and the alignment diagrams in FIG. 9 and FIG. It is the same as the alignment chart (FIG. 5, FIG. 6) in the free) mode.

  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. 11 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, an HV switching prediction unit 86, and a switching execution unit 88. The switching determination unit 84 performs, for example, traveling mode switching shown in FIG. 12 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. 13 is a traveling mode switching map when input / output (charging / discharging) between battery unit 20 and motor generators MG1, MG2 is restricted by battery temperature THbat, stored power amount SOC or the like. FIG. 12 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, charge to the battery unit 20 by power generation, etc. relatively freely. is there.

  In the case of the traveling mode switching map of FIG. 13 with input / output restrictions 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. 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. 12 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 EV driving 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 travel mode is removed, the engine 12 is started to shift to the HV travel mode, but in order to reduce the shock at the engine start, the EV travel mode is executed leaving a torque for reaction force compensation at the start . As the HV travel mode, series parallel high mode, parallel high mode, and series parallel low mode are selected as in FIG. 13, but in the case of FIG. 12, the vehicle load is large because there is no input / output restriction of the battery unit 20. In the region, the parallel low mode in which torque assist (MG assist) is performed by motor generator MG1 and / or MG2 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 (in a driven state), the EV travel mode is selected in the low vehicle speed region. However, since the vehicle drive torque is not generated, the EV travel mode region can be widened.

  The switching determination unit 84 determines, for example, whether or not the traveling mode selected in accordance with the traveling mode switching map of FIG. 12 or 13 is different from the current traveling mode, and determines switching to the selected traveling mode if different. Do. Further, when the EV request switch 72 is turned ON and a signal representing the EV request Sev is supplied, the traveling of FIG. 12 is performed on the condition that there is no input / output restriction of the battery unit 20 due to the remaining charge SOC. The EV drive mode is maintained with priority given to the mode switching map.

  Here, in the EV both drive mode, as is apparent from FIG. 2, in the first engagement pattern in which one of the clutch C1 and the brake B1 is engaged and the other is released and the direct coupling clutch CS is engaged. There is a dual drive (Ne free) mode and a dual engagement (Ne = 0) mode of a second engagement pattern in which both the clutch C1 and the brake B1 are engaged and the direct coupling clutch CS is released. When it is determined that switching to the drive mode is to be performed, it becomes a problem which switching mode to switch to. The HV switching prediction unit 86 and the switching execution unit 88 switch to both drive modes of the appropriate engagement pattern based on the vehicle state etc. when the first switching determination to switch from the single drive mode to both drive modes is made. Signal processing according to steps S1 to S11 (hereinafter simply referred to as S1 to S11) in the flowchart of FIG. S3 of the flowchart of FIG. 14 corresponds to the HV switching prediction unit 86, and S4 to S11 correspond to the switching execution unit 88.

  In S1 of FIG. 14, it is determined whether or not the current traveling mode is the EV single drive mode, and if it is not the EV single drive mode, the process is ended as it is. In S2, it is determined whether or not the first switching determination to switch to both drive modes is made by the switching determination unit 84. If the first switching determination is not performed, the process ends as it is, but the first switching determination If it is done, execute S3. In S3, after switching to the EV both drive mode according to the first switching determination, it is predicted whether or not the second switching determination to switch to the HV traveling mode in which the engine 12 needs to be started is performed by the switching determination unit 84. The HV travel mode is set, for example, in a region where the vehicle load is large or in a high vehicle speed region as in the travel mode switching map of FIG. 12, so the magnitudes of the accelerator operation amount θacc and the vehicle speed V or their change rates Etc., it can be determined whether the possibility of the second switching determination being made is high. In addition, even when the possibility of remaining in the EV travel mode region is high, the second switching determination may be performed when the state of charge remaining SOC decreases, so the second switching determination is performed based on the state of charge remaining SOC. It can also be determined whether the possibility is high. Then, if it is determined 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, S7 and subsequent steps are executed.

  S4 and subsequent steps are for switching from the EV single drive mode to both drive (Ne free) modes of the first engagement pattern, and in S4, only one of the clutch C1 and the brake B1 is engaged. For example, the type of the HV traveling mode is predicted from the traveling mode switching map shown in FIG. 12 or the like so that the number of engaging elements when switching to the HV traveling mode is reduced. For example, when a series parallel low mode is predicted, the clutch C1 is engaged to establish a low gear, and when a parallel high mode or a series parallel high mode is predicted, the brake B1 is engaged to establish a high gear. Engage. Further, in S5, 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. In this state, since the engine torque Te is 0, the direct rotation clutch CS is changed by changing the engine rotation speed Ne and the MG1 rotation speed Nmg1 only with the engagement torque by the hydraulic pressure Pcs without performing synchronous control by the first motor generator MG1. It can also be engaged. Then, after the direct coupling clutch CS is completely engaged, S6 is executed, and the first motor generator MG1 is also subjected to powering control in addition to the second motor generator MG2, whereby both drive (Ne free) modes are established. In this both drive (Ne free) mode, as shown in FIG. 5 or FIG. 6, the engine 12 is rotated in accordance with the vehicle speed V. Therefore, when shifting to the HV travel mode thereafter, the engine 12 is promptly As compared with the dual drive (Ne = 0) mode in which the engine 12 can be stopped, the switching time to the HV traveling mode is shortened and excellent driving force response performance can be obtained. In this both drive (Ne free) mode, since the engine brake is generated by the co-rotation of the engine 12, the engine brake is reduced by the decompression device or the like as needed during driving.

  FIG. 15 is an example of a time chart explaining the change of the operation state of each part when the determination of S3 of the above-mentioned flowchart is YES (affirmative) and S4 and subsequent steps are executed and switching to both drive (Ne free low gear) mode. is there. A time t1 in FIG. 15 is a time when the accelerator pedal is additionally depressed in the EV single drive mode traveling only by the MG2 torque Tmg2, and the MG2 torque Tmg2 is increased with the increase of the accelerator operation amount θacc. The time t2 is the time when the first switching judgment to switch to the EV both drive mode is made with the increase of the accelerator operation amount θacc, that is, the time when the judgment of S2 becomes YES, the judgment of S3 is also YES and S4 immediately The control of the clutch C1 is started by the pressure increase of the hydraulic pressure Pc1 in this example. Time t3 is the time when synchronous control is started after clutch C1 is completely engaged, time t4 is that engine rotation speed Ne and MG1 rotation speed Nmg1 become substantially the same, and engagement control of direct coupling clutch CS is It is the time started. A time t5 is a time when the direct coupling clutch CS is completely engaged, after which the MG1 torque Tmg1 is raised to establish the both drive (Ne free low gear) mode.

  Referring back to FIG. 14, if the determination in S3 is NO (negative), that is, if it is determined that the possibility of the second switching determination to switch to the HV traveling mode is low, S7 is executed. In S7, it is determined whether or not the travel in only the EV travel mode is limited. Specifically, when the EV request switch 72 is turned ON and a signal representing the EV request Sev is supplied, or when the state of charge SOC is equal to or higher than the predetermined value and charging is not possible, traveling only in the EV travel mode It is determined that the state is maintained, and S8 and subsequent steps are executed. Steps S8 and S9 are to switch from the EV single drive mode to both drive (Ne = 0) mode of the second engagement pattern, and in S8 both the clutch C1 and the brake B1 are engaged while the direct coupling clutch CS is released. . In the EV single drive mode, since both the mechanical transmission unit 44 and the electric differential unit 46 are in the neutral state (neutral state), the ring gear of the electric differential unit 46 whose rotational speed is defined according to the vehicle speed V The rotation can be freely changed except for R2, and the clutch C1 and the brake B1 can be engaged promptly without performing synchronous control. If necessary, the torque Tmg1 of the first motor generator MG1 may be controlled so that the rotational speed of the carrier CA2 of the electric differential portion 46 becomes zero. In S9, both the drive (Ne = 0) mode is established by performing powering control of the first motor generator MG1 in addition to the second motor generator MG2. In this both drive (Ne = 0) mode, as shown in Fig. 4, the engine rotation speed Ne is maintained at a stationary state of 0, so both drive of the first engagement pattern in which the engine 12 is rotated together. Excellent fuel efficiency can be obtained compared to the Ne free mode.

  FIG. 16 is a time chart for explaining the change in the operating state of each part when the determination of S3 is NO and thus S8 and S9 are executed following S7 and switching to the both drive (Ne = 0) mode is made. It is an example. Time t1 in FIG. 16 is a time when the accelerator pedal is additionally depressed in the EV single drive mode traveling with only MG2 torque Tmg2, and MG2 torque Tmg2 is increased as the accelerator operation amount θacc increases. The time t2 is the time when the first switching judgment to switch to the EV both drive mode is made with the increase of the accelerator operation amount θacc, that is, the time when the judgment of S2 becomes YES, the judgment of S3 is NO and continues to S7. Then, S8 is executed, and the engagement control of the clutch C1 and the brake B1 is started by the pressure increase of the hydraulic pressure Pc1, Pb1. The time t3 is the time when the clutches C1 and B1 are completely engaged, after which the MG1 torque Tmg1 is increased to establish the both drive (Ne = 0) mode.

  Referring back to FIG. 14, when the determination in S7 is NO, that is, when the vehicle is not limited to traveling only in the EV travel mode, S10 is performed. In S10, the drive mode is switched to both the first engagement pattern or the second engagement pattern according to the vehicle state and the like. For example, in order to switch to both drive (Ne = 0) mode of the second engagement pattern basically having excellent fuel efficiency, both the clutch C1 and the brake B1 are engaged while the direct coupling clutch CS is released. In the drive (Ne = 0) mode, the engine brake does not work, so when the vehicle is in a state where engine brake is expected to be required, switching to both drive (Ne free) mode of the first engagement pattern that enables engine brake Is desirable. The vehicle state requiring the engine brake is, for example, a case where traveling on a downward slope is predicted, or a case where regenerative control of the motor generators MG1 and MG2 is limited due to a large remaining charge amount SOC. Then, in the next S11, both the drive modes are established by performing the powering control of the first motor generator MG1 in addition to the second motor generator MG2.

  As described above, in the hybrid vehicle 10 of the present embodiment, since the engine 12 and the first motor generator MG1 can be connected by the direct coupling clutch CS, the direct coupling clutch CS is brought into the connected state and the mechanical transmission portion 44 is disconnected. By setting the neutral state), the first motor generator MG1 is rotationally driven by the engine 12 to generate electric power, and a series mode in which the second motor generator MG2 is driven by the power generation control by the generated electric power becomes possible. The types of travel modes that can be performed increase, and fuel efficiency and power performance can be further improved.

  On the other hand, in the case of the hybrid vehicle 10 having the direct coupling clutch CS, both drive (Ne free) mode of the first engagement pattern and both drive (Ne = 0) modes of the second engagement pattern are possible as EV both drive modes. However, in the present embodiment, when the first switching determination to switch from the EV single drive mode to the both drive modes is performed, it is predicted whether the second switching determination to switch to the HV traveling mode is further performed (S3) When the second switching determination is predicted, the mode is switched to both drive (Ne free) modes of the first engagement pattern. In this both drive (Ne free) mode, since the engine 12 is co-rotated according to the vehicle speed V, it is possible to quickly start the engine 12 when shifting to the HV traveling mode, and the engine 12 rotates. Compared to the both drive (Ne = 0) mode of the second engagement pattern to be stopped, the switching time to the HV travel mode is shortened, and excellent drive force response performance is obtained.

  Further, in the present embodiment, when the possibility of the second switching determination being performed is low, it is determined whether the travel is limited to the EV travel mode only (S7), and the vehicle is limited to the EV travel mode only. If there is, the mode is switched to the both drive (Ne = 0) mode of the second engagement pattern (S8). Even when the vehicle is not limited to traveling only in the EV traveling mode, the mode is basically switched to the both driving (Ne = 0) mode of the second engagement pattern except for certain conditions such as high necessity of engine braking (S10). In this both drive (Ne = 0) mode, the engine rotational speed Ne is maintained in the stationary state of 0, so that the engine 12 is compared with both drive (Ne free) modes of the first engagement pattern in which the engine 12 is rotated together. Excellent fuel efficiency.

  That is, when switching to the EV both drive mode, if there is a high possibility of switching to the HV travel mode, switching to the HV travel mode is excellent by switching to the both drive (Ne free) mode of the first engagement pattern. In addition, when the possibility of switching to the HV travel mode is low, basically, switching to the second engagement pattern both drive (Ne = 0) mode provides excellent fuel efficiency. It can be secured.

  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: driving wheel 44: mechanical transmission unit (stepped transmission unit) 45: connection member (output member) 46: electric differential unit 48: first planetary gear mechanism 50: second planetary gear mechanism Gear mechanism (differential mechanism) 80: electronic control device 82: traveling mode switching control unit (traveling mode switching control device) 84: switching determination unit 86: HV switching prediction unit 88: switching execution unit S1: sun gear (first rotating element ) CA1: carrier (second rotating element) R1: ring gear (third rotating element) CA2: carrier (fourth rotating element) S2: sun gear (fifth rotating element) R2: ring gear (sixth rotating element) MG1: first Motor generator (first rotating machine) MG2: Second motor generator (second rotating machine) C1: Clutch (clutch for shifting) B1: Brake (gearshift brake) CS: Direct coupling clutch (direct coupling engagement part)

Claims (1)

The first rotation element is selectively stopped by the transmission brake, the second rotation element is connected to the engine in a power transmitting manner, and the third rotation element is connected to the output member, and the first rotation element A planetary gear type stepped transmission, in which any two of the third rotating elements are selectively connected by a transmission clutch;
It has a fourth rotating element connected to the output member of the stepped transmission, a fifth rotating element to which the first rotating machine is connected for power transmission, and a sixth rotating element functioning as an output element. An electric differential unit including a differential 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 state in which the operation of the engine is stopped and a hybrid vehicle capable of traveling in a state in which the engine is operated, the EV traveling mode and the HV traveling mode In the traveling mode switching control device which travels while switching between
The hybrid vehicle includes a direct coupling engagement portion capable of selectively coupling the engine and the first rotating machine.
In the EV travel mode, one of the shift brake and the shift clutch is engaged and the other is released and the direct engagement portion is engaged, the first rotating machine and the second rotation Both drive modes of the first engagement pattern which can travel using both of the machines as a drive source for traveling, the state in which both the shift brake and the shift clutch are engaged and the direct engagement portion is released , Both drive modes of the second engagement pattern capable of traveling using both the first rotating machine and the second rotating machine as a traveling drive source, the shift brake, the shift clutch, While a single drive mode is possible in which only the second rotating machine is used as a drive source for traveling in a state where all of the direct coupling engagement parts are released,
A switching determination unit that determines switching of a plurality of travel modes including the single drive mode, the both drive modes, and the HV travel mode according to a predetermined travel mode switching condition;
When the first switching determination to switch from the single drive mode to the both drive modes is made by the switching determination unit, the second switching determination to switch to the HV travel mode after switching to the both drive modes is the switching determination unit HV switching prediction unit that predicts whether or not to
A switching execution unit configured to switch to both drive modes of the first engagement pattern when it is predicted that the second switching determination is to be performed by the HV switching prediction unit;
A traveling mode switching control device for a hybrid vehicle, comprising:

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