JP2018001949A - Travel mode switching control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable consecutive multiple switching among travel modes within time as short as possible.SOLUTION: A travel mode switching control device for a hybrid vehicle performs steps comprising: when a first switching determination to switch from an EV single driving C1 ON mode to a parallel high mode is done (i.e. a determined result of S2 is YES), predicting whether or not a second determination to switch to a parallel low mode will be done in the middle of the travel mode switching according to the first switching determination (S3); when the result is YES, performing operations from S4, to start an engine before changing gear stages, while when the result is No, performing operations from S8, to change the gear stages before the engine starts. In the case the operation is performed from S4, when the second switching determination is actually done (i.e. a determined result of S5 is YES), S7 is performed to engage a direct clutch CS to directly establish a parallel low mode without switching the gear stages, thereby, allowing switching to the parallel low mode to be done in shorter time, to enhance drivability performance.SELECTED DRAWING: Figure 12

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 unit coupled to the engine so as to be capable of transmitting power and capable of establishing a plurality of gear stages having different power transmission states; and (b) coupled to an output member of the mechanical transmission unit. A differential mechanism having a first rotating element, a second rotating element to which the first rotating machine is connected so as to be able to transmit power, and a third rotating element functioning as an output element, and operating the first rotating machine An electric differential unit that controls a differential state of the differential mechanism by controlling the state; and (c) a second rotating machine coupled to the drive wheel so as to be capable of transmitting power, d) There has been proposed a hybrid vehicle capable of traveling in a plurality of traveling modes in which one of the engine operation, non-operation, and the gear stage is different. The device described in Patent Document 1 is an example, and when switching from EV (Electric Vehicle) running in which the engine is not operated to HV (Hybrid Vehicle) running with a change in gear stage, the engine is stopped after changing the gear stage. The system starts with ranking (see FIG. 9 of the same document).

International Publication No. 2013/114594

  However, in such a hybrid vehicle, multiple switching in which the driving mode is continuously switched in a short time may occur, and the next driving mode is switched after the first driving mode switching is completed. As a result, the time required for switching becomes longer and the drivability such as responsiveness to driving force may be impaired. For example, in the case of the hybrid vehicle described in Patent Document 1, there is a possibility of switching from EV single motor driving to HV high gear driving and further to HV low gear driving by depressing the accelerator pedal, etc., but switching to high gear stage is possible. Therefore, after the engine is started, it is necessary to switch to the low gear stage, which increases the time required for switching.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to perform multiple switching in which the traveling modes are continuously switched in as short a time as possible.

  The present invention includes: (a) a mechanical transmission unit that is coupled to an engine so as to be capable of transmitting power and can establish a plurality of gear stages having different power transmission states; and (b) an output member of the mechanical transmission unit. A first rotating element coupled to the first rotating machine, a second rotating element coupled to the first rotating machine so that power can be transmitted, and a third rotating 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 wheel so as to be able to transmit power. (D) a hybrid vehicle capable of traveling in a plurality of traveling modes in which any one of the engine operation, non-operation and the gear stage is different, and (e) a traveling mode in which the plurality of traveling modes are switched while traveling In the switching control device, (f) predetermined travel And (g) a first switching determination for switching between operation and non-operation of the engine and changing the gear stage by the switching determination unit. When the travel mode switching control is performed in accordance with the first switching determination, the second switching determination is performed to switch to another traveling mode in which the gear stage is changed without changing the operation or non-operation of the engine. And (h) when it is predicted that the second switching determination will be performed by the multiple switching prediction unit, the change of the gear stage is performed. If it is not predicted that the second switching determination will be performed while the engine is switched between operation and non-operation in advance, the engine is switched between operation and non-operation before switching. And (i) the switching execution unit switches between operation and non-operation of the engine when the second switching determination is predicted to be performed. Before the change of the gear stage is performed, it is determined whether or not the second switching determination is actually performed by the switching determination unit. When the second switching determination is performed, the change of the gear stage is determined. The change is omitted, and the mode is switched to the other travel mode.

  In such a travel mode switching control apparatus for a hybrid vehicle, when the first switching determination is performed, it is predicted whether or not the second switching determination is performed during the traveling mode switching control, and the second switching determination is performed. Is predicted, the engine operation is switched between inactive and inactive prior to the gear change. On the other hand, if the second switching judgment is not predicted, the engine speed is changed in advance before the engine is switched between inactive and inactive. Run. If it is predicted that the second switching determination will be made, whether or not the second switching determination has actually been made before changing the gear stage after switching between engine operation and non-operation. When the second switching determination is made, the gear position change is omitted and switching to another traveling mode by the second switching determination is performed, so that switching to the other traveling mode is performed in a short time. Thus, drivability performance such as driving force responsiveness is improved.

FIG. 2 is a skeleton diagram illustrating a schematic configuration related to traveling of a hybrid vehicle to which the present invention is applied, and is a diagram illustrating a main part of a control system. FIG. 2 is a diagram for explaining a plurality of travel modes that can be realized by the hybrid vehicle of FIG. 1 and operating states of respective parts in the travel modes. It is an example of a collinear diagram of a mechanical transmission unit and an electric differential unit in the EV single drive mode. It is an example of a collinear diagram of a mechanical transmission unit and an electric differential unit in both EV drive modes. It is an example of a collinear diagram of a mechanical transmission unit and an electric differential unit in the HV series parallel high mode. It is an example of a collinear diagram of a mechanical transmission unit and an electric differential unit in the HV series parallel low mode. It is an example of a collinear diagram of a mechanical transmission unit and an electric differential unit in the HV parallel high mode. It is an example of a collinear diagram of a mechanical transmission unit and an electric differential unit in the HV parallel low mode. It is an example of a collinear diagram of a mechanical transmission unit and an electric differential unit in the HV series mode. It is a figure explaining an example of the driving mode switching map when there is no battery input / output restriction. It is a figure explaining an example of the travel mode switching map in case there exists an input / output restriction | limiting of a battery. 2 is a flowchart for specifically explaining the operation of a travel mode switching control unit functionally provided in the electronic control device of FIG. 1. FIG. 13 is an example of a time chart for explaining changes in the operating state of each part when step S3 in the flowchart of FIG. 12 is YES (positive) and the engine is started prior to a change in gear position. FIG. 13 is an example of a time chart for explaining a change in the operating state of each part when step S3 in the flowchart of FIG. 12 is NO (negative) and the gear stage is changed prior to engine start. It is the figure which illustrated the change of the alignment chart of the time t1-t3 part in the time chart of FIG. It is the figure which illustrated the change of the alignment chart of the time t3-t6 part in the time chart of FIG. It is the figure which illustrated the change of the collinear diagram of the time t4-t8 part in the time chart of FIG.

  As the mechanical transmission unit, for example, a plurality of gear stages having different gear ratios can be established by a plurality of transmission engagement devices, and a planetary gear type or a parallel type capable of a cut-off state (neutral) for cutting off power transmission. A stepped mechanical transmission such as a shaft type is suitable. The plurality of gear stages can be determined so as to include both a reduction gear stage (underdrive) having a gear ratio larger than 1 and an acceleration gear stage (overdrive) having a gear ratio smaller than 1. It may include only one of the gear stage and the speed increasing gear stage. The shut-off 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 planetary gear mechanism of a single pinion type or a double pinion type is provided. The planetary gear mechanism includes three rotating elements, that is, a sun gear, a carrier, and a ring gear. In a collinear diagram in which these rotating speeds can be connected by a straight line, for example, a rotating element that is positioned at an intermediate position is an intermediate rotating element. The engine is connected to the carrier of the single pinion type planetary gear mechanism and the ring gear of the double pinion type planetary gear mechanism, and one of the rotating elements on both sides functions as an output element, and the other is selectively non-rotatable via a brake. By being fixed, a speed increasing gear stage having a gear ratio smaller than 1 is established. Further, by selectively connecting any two of the three rotating elements with a clutch, it is possible to establish a constant speed gear stage with a gear ratio of 1 at which the planetary gear mechanism rotates integrally. In the collinear diagram, when a rotating element located in the middle is used as an output element, the engine is connected to one of the rotating elements on both sides, and the other can be selectively fixed to be non-rotatable by a brake, the gear ratio is 1. A larger reduction gear can be established.

  As the differential mechanism of the electric differential section, a single planetary gear mechanism of a single pinion type or a double pinion type is preferably used. This planetary gear mechanism has three rotating elements, a sun gear, a carrier, and a ring gear. In a collinear diagram in which these rotating speeds can be connected with a straight line, for example, the rotating speed located in the middle is an intermediate rotating speed. The output member of the mechanical transmission unit is connected to the elements (the carrier of the single pinion type planetary gear mechanism, the ring gear of the double pinion type planetary gear mechanism), and the first rotating machine and the driving wheel are connected to the rotating elements on both sides. You may make it connect a driving wheel to an intermediate rotation element. A 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 state, or the first rotation. It is also possible to limit the differential rotation by making it possible to stop the rotation element to which the machine is connected by a brake.

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

  The switching determination unit performs switching determination according to a driving mode switching condition such as a driving mode switching map or a mode area map that is determined using, for example, a driving state such as an accelerator operation amount and a vehicle speed. A plurality of types of driving mode switching conditions can be determined according to the vehicle state such as the remaining battery charge of the battery, and the basic driving mode switching conditions can be corrected according to the vehicle state. And this invention is applied suitably, for example, when it switches to three or more types of driving modes according to vehicle loads, such as accelerator operation amount. When the driving mode switching condition is set with 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 (accelerator change rate, etc.) of the vehicle load. Whether or not it can be predicted. When the driving mode is switched according to the vehicle speed, it is possible to predict whether or not the second switching determination is made based on the rate of change (acceleration / deceleration) of the vehicle speed. The prediction mode is possible.

  The switching execution unit determines whether or not the second switching determination is actually performed by the switching determination unit before executing the gear change in the traveling mode switching based on the first switching determination, and performs the second switching determination. In this case, a jump switching unit that switches to another traveling mode based on the second switching determination without changing the gear stage in the traveling mode switching based on the first switching determination is provided. Another travel mode is a travel mode in which the change destination of the gear stage is different while switching between engine operation and non-operation as it is compared to the travel mode of the switch destination based on the first switching determination, and a new gear stage change The gear may be the gear before the driving mode is switched based on 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 configured such that one of a pair of shift engagement devices is engaged and the other is released, and the other is engaged. And (b) the hybrid vehicle is configured such that the engine is in an inoperative state and the first gear stage is in the plurality of travel modes. (C) a first traveling mode of the engine, wherein the engine is in an operating state and the second traveling mode of the second gear stage, and the engine is in an operating state and the third traveling mode of the first gear stage. The multiple switching prediction unit is configured to switch to the second traveling mode according to the first switching determination when the switching determination unit performs the first switching determination to switch from the first traveling mode to the second traveling mode. Mode switching control is performed The second switching determination to switch to the third travel mode is predicted by the switching determination unit. (D) The switching execution unit is configured to predict the second switching determination by the multiple switching prediction unit. Is predicted to be performed, the engine is started prior to the change to the second gear stage, whereas if the second switching determination is not predicted to be performed, the engine is started prior to starting. And changing to the second gear stage. The third travel mode corresponds to another travel mode, and when switching to the third travel mode according to the second switching determination, the third travel mode is established while maintaining the first gear without changing to the second gear. Can be made. Further, if the second switching determination is not predicted, the change to the second gear stage is performed prior to the start of the engine, but in the first traveling mode, the engine is inoperative and the entire mechanical transmission is stopped. Therefore, the engagement / release control of the pair of shift engagement devices can be performed in a short time without causing a shift shock.

  The hybrid vehicle includes, for example, a connecting device that connects and disconnects the engine and the first rotating machine. In that case, a traveling mode in which the operating state of the coupling device is different as the traveling mode is possible. For example, the first rotating machine is driven by the engine by setting the coupling device to the connected state and the mechanical transmission unit to the disconnected state. Can be driven to rotate to generate power, and the generated power can be used to execute a series mode in which the second rotating machine is controlled by powering. The connecting device may be only a connecting / disconnecting device such as a clutch, but can also be connected via a transmission. The present invention can also be applied to a hybrid vehicle that does not include such a coupling 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 related to travel of a hybrid vehicle 10 to which the present invention is applied, and is a diagram that also shows a main part of a control system related to travel mode switching control. In FIG. 1, the hybrid vehicle 10 includes an engine 12, a first motor generator MG1, and a second motor generator MG2 that can be used as a driving source for traveling, and drives wheels (front wheels) via a power transmission device 14. ) 16 is driven to rotate. The engine 12 is an internal combustion engine that outputs power by burning predetermined fuel, such as a gasoline engine or a diesel engine. The engine 12 controls the engine torque Te by controlling the operating state such as the intake air amount, the fuel supply amount, and the ignition timing by the electronic control unit 80.

  Both the first motor generator MG1 and the second motor generator MG2 can alternatively be used as an electric motor and a generator (generator). The first motor generator MG1 and the second motor generator MG2 are connected to the battery unit 20 via a power control unit 18 having an inverter unit, a smoothing capacitor, and the like, 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 that are the respective torques (power running torque or regenerative torque) of the first motor generator MG1 and the second motor generator MG2 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 an FF (front engine / front drive) type vehicle, and is housed in a transaxle case 22 which is a non-rotating member together with the first motor generator MG1 and the second motor generator MG2. The power transmission device 14 transmits the output of at least one of the engine 12 and the first motor generator MG1 to the drive wheels 16 and the second power of the second motor generator MG2 transmits to the drive wheels 16. And a power transmission unit 26. The first power transmission unit 24 includes a mechanical transmission unit 44 and an electrical differential unit 46. The drive gear 28, which is an output member of the electrical differential unit 46, drives the driven gear 30, the driven shaft 32, and the final gear. 34, power is transmitted to the differential device 38 via the differential ring gear 36, and is distributed to the left and right drive wheels 16 via a pair of axles 40.

  The mechanical transmission unit 44 and the electric differential unit 46 are arranged coaxially with the input shaft 42 that is rotationally driven by the engine 12, and the mechanical transmission unit 44 includes the first planetary gear mechanism 48, the clutch C1, and A brake B1 is provided. The first planetary gear mechanism 48 includes, as three rotational elements capable of differential rotation, a sun gear S1, a carrier CA1 that supports the pinion gear P1 so as to rotate and revolve, and a ring gear R1 that meshes with the sun gear S1 via the pinion gear P1. In the pinion type planetary gear mechanism, the carrier CA1 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 connected to the transaxle case 22 via the brake B1, and the sun gear S1 and the carrier CA1 are selectively connected to each other via the clutch C1. . The ring gear R <b> 1 is coupled to the electrical differential unit 46 via a coupling member 45 that functions as an output member of the mechanical transmission unit 44.

  Each of the clutch C1 and the brake B1 is a multi-plate hydraulic friction engagement device that is controlled to be engaged by a hydraulic actuator, and the oil path switching valve and the hydraulic control valve of the hydraulic control circuit 52 are controlled by the electronic control unit 80. Thus, engagement and release are controlled according to the C1 oil pressure Pc1 and the B1 oil pressure Pb1 supplied from the oil pressure control circuit 52, respectively. 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 rotates freely and cannot take the reaction torque of the engine torque Te. The unit 44 is in a neutral state (neutral state) and is in a cut-off state in which power transmission is not possible. When both the clutch C1 and the brake B1 are engaged, the first planetary gear mechanism 48 is integrally stopped from rotating, and the engine 12 is held in the rotation stopped 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, and the rotational speed (engine rotational speed) Ne of the engine 12 is constant, that is, the gear ratio. When γ1 = 1, the electric power is output from the ring gear R1 to the electric differential section 46 via 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 stopped from rotating, so that the ring gear R1 is rotated at an increased speed with respect to the input shaft 42, and the gear ratio γ1 <1. Is output to the electric differential section 46 via the connecting member 45. In other words, the mechanical transmission unit 44 functions as a two-stage stepped transmission that can be switched between a low gear stage in a directly connected state (gear ratio γ1 = 1) and a high gear stage in an overdrive state (gear ratio γ1 <1). . The low gear stage corresponds to the first gear stage, and the high gear stage corresponds to the second gear stage. The clutch C1 and the brake B1 are shift engagement devices.

  The collinear 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 collinear diagram can connect the rotational speeds of the three rotating elements (sun gear S1, carrier CA1, and ring gear R1) of the first planetary gear mechanism 48 with a straight line, and three vertical lines representing each rotating element. 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 unit 46 includes a second planetary gear mechanism 50. The second planetary gear mechanism 50 is a single rotating gear having three rotational elements capable of differential rotation, including a sun gear S2, a carrier CA2 that supports the pinion gear P2 so as to rotate and revolve, and a ring gear R2 that meshes 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 generates a differential action. The carrier CA <b> 2 is integrally connected to the connecting member 45 and functions as an input member of the electric differential unit 46. Sun gear S2 is integrally connected to rotor shaft 54 of first motor generator MG1 for differential control. The ring gear R2 is integrally connected to the drive gear 28 that functions as an output member of the electric differential section 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 connected to the input shaft 42 via a direct clutch CS. The direct coupling clutch CS is a multi-plate hydraulic friction engagement device that is controlled to be engaged by a hydraulic actuator. Like the clutch C1 and the brake B1, an oil path switching valve and a hydraulic control valve of the hydraulic control circuit 52 are provided. By being controlled by the electronic control unit 80, the engagement and release are controlled according to the CS oil pressure Pcs supplied from the oil pressure control circuit 52. This direct coupling clutch CS is a connecting / disconnecting device that can connect and disconnect power transmission, and corresponds to a connecting device that connects and disconnects between 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 the electric differential unit 46, in addition to mechanical power transmission distributed to the ring gear R2, the first motor generator MG1 is driven to rotate by the power distributed to the first motor generator MG1, The second motor generator MG2 can be driven by the generated power, or the battery unit 20 can be charged. 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, so that the speed ratio γ2 (= rotation speed of the carrier CA2 / ring gear R2 It functions as an electric continuously variable transmission that continuously controls the rotation speed. That is, the electric differential unit 46 includes a second planetary gear mechanism 50 as a differential mechanism, and a first motor generator as a differential control rotating machine coupled to the second planetary gear mechanism 50 so as to be able to transmit power. MG1 is an electric transmission mechanism in which the differential state of the second planetary gear mechanism 50 is controlled by controlling the operation state of the first motor generator MG1. In addition, when the direct clutch CS is engaged, the engine 12 and the first motor generator MG1 are connected, so that the first motor generator MG1 is driven to rotate by the power of the engine 12 to generate electric power. It is possible to charge battery unit 20 with electric power or drive second motor generator MG2.

  The collinear chart shown on the right side in FIGS. 3 to 9 relates to the electrical differential section 46, and “OUT” is the drive gear 28 that functions as an output member. This collinear diagram can connect the rotational speeds of the three rotating elements (sun gear S2, carrier CA2, and ring gear R2) of the second planetary gear mechanism 50 with straight lines, and three vertical lines representing each rotating element. 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 the present embodiment, the connecting member 45 is connected to a rotating element located in the middle of the nomographic chart, that is, a rotating element having a rotating speed in the differential state, which is an intermediate speed. It is designed to be entered. Further, the first motor generator MG1 and the drive wheels 16 are connected to one and the other of the two rotating elements (sun gear S2 and ring gear R2) located on both sides of the nomograph so as to be able to transmit power.

  In first power transmission unit 24 configured in this way, the power of engine 12 and the power of first motor generator MG1 are transmitted from drive gear 28 to driven gear 30. Therefore, the engine 12 and the first motor generator MG1 are coupled to the drive wheels 16 via the first power transmission unit 24 so that power can be transmitted. In addition, since mechanical transmission unit 44 transmits power in a directly connected state or an overdrive state, an 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, the overall transmission ratio γ0 of the first power transmission unit 24 can be achieved by shifting the mechanical transmission unit 44. (= Γ1 × γ2) is also changed. Therefore, the shift of the electrical differential unit 46 is executed in accordance with the shift of the mechanical transmission unit 44 so that the change of the transmission 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 unit 44 is upshifted from the low gear stage to the high gear stage, the electrical differential unit 46 is downshifted at the same time. Accordingly, the first power transmission unit 24 can function as a so-called electric continuously variable transmission as a whole.

  Second power transmission unit 26 is integrally attached to rotor shaft 56 of second motor generator MG2 arranged in parallel to input shaft 42 separately from input shaft 42, and meshes with 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 is transmitted to the differential device 38 via the driven shaft 32, the final gear 34, and the diff ring gear 36. . That is, the second motor generator MG2 is connected to the drive wheel 16 so as to be able to transmit power without passing through the mechanical transmission unit 44 and the electric differential unit 46 of the first power transmission unit 24, and is connected to the reduction gear. The degree of freedom of 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 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, and the CPU uses a temporary storage function of the RAM according to a program stored in the ROM in advance. Various controls of the hybrid vehicle 10 are executed by performing signal processing. For example, the electronic control unit 80 performs output control of the engine 12, the first motor generator MG1, and the second motor generator MG2, switching control of a plurality of travel modes, and the like. It is configured separately for engine control, MG control, hydraulic control and the like.

  The electronic control unit 80 includes an engine rotation speed sensor 60, 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 the shift position sensor 70, the battery sensor 72, etc., that is, the engine rotational speed Ne, the output rotational speed Nout that is the rotational speed of the driven gear 30 corresponding to the vehicle speed V, the rotational speed of the first motor generator MG1 ( MG1 rotation speed) Nmg1, second motor generator MG2 rotation speed (MG2 rotation speed) Nmg2, accelerator pedal operation amount (accelerator operation amount) θacc, shift lever operation position Psh, battery temperature THbat of battery unit 20 and battery charge Discharge current I at, such as the battery voltage Vbat, various information is supplied necessary for control. The electronic control unit 80 also outputs an engine control command signal Se, an MG control command signal Sm, a hydraulic control command signal Sp, and the like to the engine 12, the power control unit 18, the hydraulic control circuit 52, and the like. The electronic control unit 80 calculates the remaining 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 travel mode switching control unit 82 that travels while switching between a plurality of travel modes according to 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 the vehicle travels 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 mode, at least the engine 12 is in an operating state and travels using only the engine 12 as a travel drive source, or at least one of the first motor generator MG1 and the second motor generator MG2 is traveled under certain conditions. This is a control mode for traveling as a drive source. In the EV mode, two travel modes, that is, a single drive mode and a double drive mode are further defined. In the HV mode, three travel modes, a series parallel mode, a parallel mode, and a series mode, are defined.

  FIG. 2 is a diagram illustrating operating states of the clutch C1, the brake B1, the direct coupling clutch CS, and the motor generators MG1 and MG2 in each travel mode. In FIG. 2, “◯” means engagement of the engagement devices (C1, B1, CS), blank means release, and “Δ” means that the engine 12 is in a stopped state. It means that one of them is engaged when an engine brake (also referred to as an emblem) is used. “G” means that the motor generators MG1 and MG2 mainly function as generators, and “M” causes the motor generators MG1 and MG2 to function mainly as electric motors when driven, and mainly as generators when driven. Means to function. However, in the HV parallel mode, the motor generators MG1 and MG2 are operatively operated as electric motors at high loads and the like, and are stopped (free rotation state) at low loads.

  Specifically, each travel mode will be described. In the single drive mode of the EV, the second motor generator MG2 is basically used as a travel drive source with all of the clutch C1, the brake B1, and the direct coupling clutch CS released. And run. FIG. 3 is an alignment chart in the EV single drive mode. When the clutch C1 and the brake B1 are released, 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 power transmission is interrupted. When the mechanical transmission unit 44 is in the neutral state, the reaction force torque of the MG1 torque Tmg1 cannot be obtained by the carrier CA2 connected to the ring gear R1, so the electric differential unit 46 is also in the neutral state and the first power The transmission unit 24 becomes neutral as a whole. In this state, the operation of the engine 12 is stopped, and the traveling MG2 torque (power running torque) Tmg2 is output from the second motor generator MG2. During reverse travel, the second motor generator MG2 is reversely rotated relative to forward travel. During traveling of the vehicle, 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 wheels 16 is also agreed). In the EV single drive mode, the first motor generator MG1 may be idled with no load, but the MG1 rotation speed Nmg1 is maintained at zero (rotation stopped 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 function as a generator, and the MG1 rotation speed Nmg1 can be made zero by feedback control. Alternatively, the d-axis lock control (control for supplying only the d-axis current in the dq axis coordinate system) for supplying current so that the rotation of the first motor generator MG1 is fixed is executed, and the MG1 rotation speed Nmg1 is zero. Can also be maintained. Further, even if the MG1 torque Tmg1 is set to zero, it is not necessary to add the MG1 torque Tmg1 if the MG1 rotation speed Nmg1 can be maintained at zero by the cogging torque of the first motor generator MG1. Even if control is performed to maintain the MG1 rotation speed Nmg1 at zero, the first power transmission unit 24 is in a neutral state, and thus does not affect the drive torque.

  In the EV single drive mode, the ring gear R1 is rotated together with the carrier CA2. However, since the mechanical transmission 44 is in a neutral state, the stopped engine 12 is not rotated and is rotated at zero rotation. Stopped. Therefore, when the second motor generator MG2 is regeneratively controlled (also referred to as power generation control) during traveling in the EV single drive mode, a large regeneration amount can be obtained. When the battery unit 20 is in a fully charged state during traveling in the EV single drive mode and regenerative energy cannot be obtained, it is conceivable to use an engine brake together. When the engine brake is used together, the brake B1 or the clutch C1 is engaged (see the combination of the emblem in the EV single drive mode in FIG. 2). When the brake B1 or the clutch C1 is engaged, the engine 12 is rotated and the engine brake is applied. By increasing the MG1 rotation speed Nmg1 by the power running control of the first motor generator MG1 or the like, the engine rotation speed Ne when the engine 12 is rotated 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. If necessary, the engine speed Ne is increased by the power running control of the first motor generator MG1, and ignition is performed. At this time, the second motor generator MG2 additionally outputs a reaction force canceling torque. 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 rotation speed Ne may be increased by engaging the brake B1 or the clutch C1 after the rotation of the carrier CA2 is pulled up by the first motor generator MG1. It is also possible to perform cranking by engaging the direct clutch CS and directly increasing the rotational speed Ne of the engine 12 by the first motor generator MG1.

  In FIG. 2, in both EV drive modes (“Ne = 0”), both the motor generators MG1 and MG2 are driven for traveling while the clutch C1 and the brake B1 are both engaged and the direct clutch CS is released. Travel using as a source. FIG. 4 is a collinear diagram in the 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 first planetary gear mechanism 48 stops the rotation of any rotating element. 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 connecting member 45 is also stopped. When the rotation of the carrier CA2 is stopped, a reaction force torque of the MG1 torque Tmg1 is obtained at the carrier CA2. Therefore, the driving force is mechanically output from the ring gear R2 by the MG1 torque (here, the power running 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 traveling MG1 torque Tmg1 and MG2 torque Tmg2 are output from first motor generator MG1 and second motor generator MG2, respectively. In this EV both drive mode, it is also possible to reverse travel by rotating both the first motor generator MG1 and the second motor generator MG2 backward with respect to the forward travel time. In the EV both drive mode, the direct transmission clutch CS is engaged, and either the clutch C1 or the brake B1 is engaged to keep the mechanical transmission unit 44 in the high gear stage or the low gear stage. It is also possible to travel using both the motor generators MG1 and MG2 as a travel drive source while rotating the engine 12 at a predetermined rotational speed.

  In the EV both drive mode, even when the required drive torque can be provided only by the second motor generator MG2, the operating point of the second motor generator MG2 represented by the MG2 rotation speed Nmg2 and the MG2 torque Tmg2 is the second motor generator. When it is within the region where the efficiency of MG2 is deteriorated, in other words, when 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 first motor generator MG1 and the second motor generator MG2 share the required drive torque based on the operation 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 disengaged, and either 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. Thus, the engine 12 is operated (actuated) and the second motor generator MG2 is controlled by powering, so that both of them travel as a driving source for traveling. FIG. 5 is a collinear diagram when the mechanical transmission unit 44 is in the high gear stage in the series parallel mode, and FIG. 6 is a collinear diagram when the mechanical transmission unit 44 is in the low gear stage in the series parallel mode. FIG. When the clutch C1 or the brake B1 is engaged, the mechanical transmission unit 44 is brought into a non-neutral state, that is, a power transmission state, and the first motor generator MG1 takes a reaction force to the power of the engine 12 transmitted to the carrier CA2. As a result, a part of the engine torque Te (engine direct torque) can be mechanically output from the ring gear R2 and transmitted to the drive wheels 16. The first motor generator MG1 is regeneratively controlled and used as a generator, and can take charge of the reaction force. The first motor generator MG1 controls the second motor generator MG2 with the generated power to output the MG2 torque Tmg2. In this series parallel mode, it is also possible to travel backward by rotating the second rotating machine MG2 reversely with respect to the forward movement.

  Here, the MG1 rotation speed Nmg1 becomes zero, and the power of the engine 12 does not pass through the electric path (electric power transmission path that is an electric path related to power transmission / reception of the first motor generator MG1 and the second motor generator MG2). At a so-called mechanical point where all of the power is 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 section 46 is maximum. “1”. This mechanical point is a state in which the MG1 rotational speed Nmg1 of the electric differential section 46 is zero in the collinear diagrams of FIGS. 5 and 6 (that is, the rotational speed of the sun gear S2 is zero). In the series parallel mode, the mechanical transmission unit 44 is switched between the high gear stage and the low gear stage, so that there are two mechanical points. By having the high gear stage series parallel mode, the mechanical points increase to the high vehicle speed side. Fast fuel economy is improved. That is, as is apparent from the travel mode switching maps of FIGS. 10 and 11, the high-gear stage parallel mode (series parallel high) is selected on the relatively high vehicle speed side, and the high vehicle speed side The mechanical points increase and the high-speed fuel consumption improves.

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

  In FIG. 2, in the HV parallel mode, the direct transmission clutch CS is engaged, and either the clutch C1 or the brake B1 is engaged, so that the mechanical transmission unit 44 is held at the high gear stage or the low gear stage. Thus, the engine 12 is operated (actuated), and the first motor generator MG1 and / or the second motor generator MG2 is subjected to power running control as necessary, so that the engine 12 travels using it as a travel drive source. FIG. 7 is a collinear diagram when the mechanical transmission unit 44 is set to the high gear stage in this parallel mode, and FIG. 8 is a collinear diagram when the mechanical transmission unit 44 is set to the low gear stage in the parallel mode. In any case, only the engine 12 is used as a driving source for traveling. However, the first motor generator MG1 and / or the second motor generator MG2 can be used as a traveling driving source by performing power running control.

  In the parallel mode, in addition to the connection of the engine 12 and the first motor generator MG1 by the engagement of the direct clutch CS, the clutch C1 or the brake B1 is engaged, so that the gear ratio γ1 of the mechanical transmission unit 44 is increased. Accordingly, the overall gear ratio γ0 of the first power transmission unit 24 is fixed. Thereby, the engine rotational speed Ne is uniquely determined with respect to the vehicle speed V (output rotational speed Nout). In the parallel mode, any power of the engine 12, the first motor generator MG1, and the second motor generator MG2 can be mechanically transmitted to the drive wheels 16. For example, during the single drive in the parallel mode, the vehicle travels by transmitting the power of the second motor generator MG2 to the drive wheels 16 in addition to the power of the engine 12. During both drivings 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 state of each engagement device (C1, B1, CS) in the parallel mode is the same as that in the EV both drive mode (Ne free) shown in FIG. That is, the alignment chart of FIGS. 7 and 8 is the same as the alignment chart 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 of the first motor generator MG1 and the power of the second motor generator MG2 are 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 therefore the engine rotation speed Ne cannot be made zero. Different from the mode (Ne = 0).

  In FIG. 2, in the HV series mode, the direct-coupled clutch CS is engaged and the clutch C1 and the brake B1 are both released, and the first motor generator MG1 is driven to rotate by the operation of the engine 12 to generate power. By powering the second motor generator MG2 with the generated power, the second motor generator MG2 is used as a driving source for traveling. FIG. 9 is a collinear diagram 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 unit 44 is in a neutral state. Accordingly, the electric differential unit 46 is in a neutral state, and the first power transmission unit 24 is also in a neutral state. In addition, in the series mode, the engine 12 and the first motor generator MG1 are connected by engaging the direct clutch CS. Therefore, by operating the engine 12, the first motor generator MG1 can be rotationally driven to generate electric 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 wheels 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, thereby driving the second motor generator MG2 with the generated electric power and driving MG2 torque Tmg2. Can be output. In the series mode, the second motor generator MG2 can be reversely rotated with respect to the forward travel to travel backward.

  The travel mode switching control unit 82 travels while switching a plurality of travel modes shown in FIG. 2, and corresponds to a travel mode switching control device. The travel 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 is, for example, the travel mode switching shown in FIGS. Switching between a plurality of travel modes is performed according to a travel mode switching condition such as a map. In the travel mode switching map, regions of the travel mode to be selected using the vehicle load such as the accelerator operation amount θacc and the vehicle speed V as parameters are determined in advance by experiments, simulations, and the like, and stored in the storage unit of the electronic control device 80 in advance. Has been. FIG. 11 is a travel mode switching map when input / output (charging / discharging) between battery unit 20 and motor generators MG1, MG2 is restricted by battery temperature THbat, remaining power storage SOC, or the like. FIG. 10 is a travel mode switching map when there is no such input / output limitation, that is, when the motor generators MG1 and MG2 can relatively freely perform torque assist by the motor generators MG2 and charging the battery unit 20 by power generation. is there.

  In the travel mode switching map of FIG. 11 in which the input / output of the battery unit 20 is restricted, 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 in preventing so-called rattling noise caused by rattling between the second motor generator MG2 and the diff ring gear 36. Then, as the vehicle speed V increases, the mode shifts 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 tends to deviate from the minimum fuel consumption operating point and is set to a relatively narrow vehicle load region. When the vehicle load increases, the mode shifts to the series parallel low mode. This driving mode is effective when the driving force is prioritized. On the other hand, when the vehicle load is negative (driven state), the series mode is set. In the series mode, the engine rotation speed Ne can be arbitrarily controlled at the same vehicle speed, and therefore engine brake torque according to the driver's request can be output. Further, since the MG1 rotational speed Nmg1 and the engine rotational speed Ne are the same, it is less subject to the restriction of the engine rotational speed Ne due to the upper limit of the MG1 rotational speed Nmg1 than in other travel modes, and the absolute value of the engine brake torque is set. Can be bigger.

  In the travel mode switching map of FIG. 10 in which the input / output of the battery unit 20 is not limited, the operation of the engine 12 is stopped and the motor generators MG1 and MG2 travel when the vehicle load is positive (driving state) and the vehicle speed is low. The EV mode to be selected is selected. In the region where the vehicle load is small, the EV single drive mode in which the vehicle travels only with the second motor generator MG2 is selected. On the relatively high load side, the EV double drive mode in which the vehicle travels with both the motor generators MG1 and MG2 is selected. When the EV mode is deviated, the engine 12 is started to shift to the HV mode. However, in order to reduce the shock at the start of the engine, the EV mode is executed while leaving a torque corresponding to the reaction force compensation at the start. 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, but in the case of FIG. Thus, the parallel low mode in which torque assist (MG assist) is performed by motor generators MG1 and / or MG2 is selected. At the time of kickdown in which the accelerator operation amount θacc increases rapidly, a parallel low mode in which MG assist is performed in preference to the travel mode switching map may be performed. On the other hand, even when the vehicle load is negative (driven state), the EV mode is selected in the low vehicle speed region. However, since the vehicle driving torque is not generated, the EV mode region can be widened.

  For example, the switching determination unit 84 determines whether or not the driving mode selected according to the driving mode switching map of FIG. 10 or FIG. 11 is different from the current driving mode, and if so, the switching determination to switch to the selected driving mode. To do. Multiple switching prediction unit 86 and switching execution unit 88 perform switching determination by switching determination unit 84 by performing signal processing in accordance with steps S1 to S10 (hereinafter simply referred to as S1 to S10) in the flowchart of FIG. The running mode switching control for switching to the running mode is executed. 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 is functionally provided with a jump switching unit, and S5 and S7 correspond to the jump switching unit.

  In S1 of FIG. 12, it is determined whether or not the current travel mode is the EV single drive C1 on mode, that is, whether or not the travel mode is the travel mode in which the clutch C1 is engaged in the EV single drive emblem combined mode in FIG. In the EV single drive C1 on mode, there is a possibility of multiple switching in which the travel mode is continuously switched when the vehicle load such as the accelerator operation amount θacc suddenly increases. For example, the EV single drive C1 ON mode may be switched to the HV parallel high mode and further to the parallel low mode. However, if these travel modes are sequentially switched, the entire travel mode is switched. The required time becomes longer, and the driving force responsiveness until a desired driving force can be obtained may be impaired. That is, in this S1, it is determined whether or not it is a travel mode in which the driving force responsiveness may be impaired by multiple switching. In this embodiment, it is determined whether or not the EV single drive C1 on mode. Other travel modes may be set according to the mode switching condition. If it is not the EV single drive C1 on mode, the process is terminated. If it is the EV single drive C1 on mode, S2 and subsequent steps are executed. The EV single drive C1 ON mode corresponds to a first traveling mode in which the engine 12 is inactive and the mechanical transmission unit 44 is in a low gear stage, and the HV parallel high mode is in the engine 12 operating state and mechanical transmission unit 44. Corresponds to a second traveling mode with a high gear stage, and the parallel low mode corresponds to a third traveling mode with the engine 12 in an operating state and the mechanical transmission unit 44 with a low gear stage.

  In S2, it is determined whether or not the switching determination unit 84 has made a first switching determination to switch to the HV parallel high mode (second traveling mode). The parallel high mode is a traveling mode in which the engine 12 is started and operated as compared with the current EV single drive C1 on mode and the mechanical transmission unit 44 needs to be switched from the low gear stage to the high gear stage. The first switching determination may be made when the accelerator pedal is depressed and reaccelerated from engine braking. If the first switching determination to switch to the parallel high mode is made, there is a possibility of multiple switching, so S3 is executed, whereas if the first switching determination is not performed, the process ends.

  In S3, while the traveling mode switching control for switching from the EV single drive C1 on mode to the parallel high mode is performed according to the first switching determination, the operation change of the engine 12 is not changed, and the change destination of the gear stage is different. It is predicted whether or not the switching determination unit 84 performs the second switching determination to switch to the traveling mode, specifically, the parallel low mode (third traveling mode). The parallel low mode is set in a region where the vehicle load is large, for example, as in the travel mode switching map of FIG. 10, and may be selected in preference to the travel mode switching map at the time of kickback when the accelerator operation amount θacc increases rapidly. In this embodiment, it is predicted that the second switching determination is likely to be performed when the change rate (accelerator change rate) Δθacc of the accelerator operation amount θacc 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 driving state such as the vehicle speed V as a parameter. If it is predicted that the second switching determination is likely to be performed, S4 and the subsequent steps are executed, and if the second switching determination is unlikely to be performed, S8 and the 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 power running control of the first motor generator MG1, thereby passing through the mechanical transmission unit 44 in the low gear stage state. Then, the engine speed Ne is increased and cranked, and when a predetermined start speed is reached, start control such as fuel injection and ignition is performed to start the engine 12. The next step S5 is executed after the engine 12 is started and reaches, for example, an idle rotation speed or the like, and determines whether or not the second switching determination to switch to the parallel low mode is actually performed by the switching determination unit 84. . When the second switching determination is actually made, S7 is executed, and when the second switching determination is not made, S6 is executed. In S6, the travel mode switching control to the parallel high mode may be continued as it is, so that the clutch C1 is disengaged and the brake B1 is engaged to change the low gear to the high gear (shift). At the same time, synchronous control is performed so that the engine rotational speed Ne and the MG1 rotational speed Nmg1 are substantially the same, and the direct 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, since it is not necessary to change the gear stage of the mechanical transmission unit 44 in S7, synchronous control is performed so that the engine rotational speed Ne and the MG1 rotational speed Nmg1 are substantially the same while maintaining the low gear stage, and the direct coupling clutch CS Engage.

  FIG. 13 is an example of a time chart for explaining the change in the operating state of each part when the determination of S3 in the above flowchart is YES, S4 and subsequent steps are executed, and the engine 12 is started prior to the change of the gear stage. 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 jumping to the parallel low mode is performed by executing S7. Time t1 in FIG. 13 is a time when the accelerator pedal is depressed for reacceleration during engine braking in the EV single drive C1 on mode. Time t2 is a time when the MG1 torque Tmg1 is set to 0 and the engine rotational speed Ne becomes substantially 0. The time t3 is the time when the first switching judgment for switching from the EV single drive C1 on mode to the parallel high mode is made, that is, the time when the judgment of S2 is YES, and the judgment of S3 is YES and S4 is immediately executed. This is the time when cranking of the engine 12 is started. Time t4 is the time when the engine 12 is started by the start control such as fuel injection. The solid line after time t5 is when S6 is NO and S6 is executed, and time t5 is the time when the clutch-to-clutch shift for changing from the low gear to the high gear is started. Time t6 is the time when the clutch-to-clutch shift is completed and the high gear is established, and the synchronous control of the engine rotational speed Ne and the MG1 rotational speed Nmg1 is completed, and the time when the engagement control of the direct clutch CS is started. is there. Time t7 is the time when the direct clutch CS is completely engaged and the parallel high mode is established.

  FIG. 15 and FIG. 16 illustrate the change in the operating state of each part in the time chart shown by the solid line in FIG. FIG. 15A shows a state during engine braking before time t1, that is, the power running control of the first motor generator MG1, and the engine rotational speed Ne is set to a predetermined rotational speed via the low gear stage mechanical transmission unit 44. It is pulled up to the state where the engine brake is effective. FIG. 15B shows the time t2 to t2 when the engine speed Ne is reduced to substantially zero and the engine braking force becomes substantially zero as the accelerator pedal is depressed, and the second motor generator MG2 drives. This is the state at t3. FIG. 16 (c) shows a state in which the engine rotational speed Ne is increased by cranking by powering control of the first motor generator MG1, and a high gear stage is established by clutch-to-clutch shift. At the same time, the engine rotation speed Ne and the MG1 rotation speed Nmg1 are synchronized and substantially synchronized.

  The alternate long and short dash line after time t5 in FIG. 13 is the case where the determination of S5 in FIG. 12 is YES and S7 is executed, and it is not necessary to change the gear stage, so immediately the engine speed Ne and MG1 rotational speed Nmg1 While synchronous control is performed, engagement control of the direct coupling clutch CS is performed.

  If it is determined in S3 in FIG. 12 that the second switching determination is unlikely to be performed, S8 and subsequent steps are executed, and the travel mode switching control from the EV single drive C1 on mode to the parallel high mode is simply performed. . That is, first, in S8, a clutch-to-clutch shift is performed in which the clutch C1 is released and the brake B1 is engaged to change from the low gear stage to the high gear stage. In this case, as shown in FIG. 15 (b), the engine rotational speed Ne is substantially 0, and the entire mechanical transmission unit 44 is in a rotation stopped state. Therefore, the clutch-to-clutch shift can be shortened without causing a shift shock. Can be done in time. In the next step S9, the engine speed Ne is increased by cranking the MG1 rotational speed Nmg1 by powering control of the first motor generator MG1 in the same manner as in S4, and the fuel injection is performed when a predetermined starting rotational speed is reached. Then, the engine 12 is started by performing start control such as ignition. In S10, synchronous control is performed so that the engine rotational speed Ne and the MG1 rotational speed Nmg1 are substantially the same, and the direct clutch CS is engaged.

  FIG. 14 is an example of a time chart for explaining the change in the operating state of each part when S8 and subsequent steps are executed following S3 and the gear stage is changed prior to the start of the engine 12, until time t3. Is the same as FIG. Time t3 is the time when the first switching determination for switching from the EV single drive C1 on mode to the parallel high mode is made, that is, the time when the determination of S2 is YES, and S8 is executed following S3. This is the time when the clutch-to-clutch shift for changing 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. The time t5 is the time when cranking of the engine 12 is started by the execution of S9, and the time t6 is the time when the engine 12 is started by the start control such as fuel injection. The time t7 is a time when the synchronous control of the engine rotational speed Ne and the MG1 rotational speed Nmg1 is started by the execution of S10, and the time t8 is a time when the engagement control of the direct clutch CS is started after the synchronization. Time t9 is a time when the parallel high mode is established after the direct coupling clutch CS is completely engaged.

  FIG. 17 illustrates the change in the operating state of each part after time t3 in the time chart of FIG. 14 with a collinear diagram, and is the same as FIG. 15 until time t3. FIG. 17 (c) shows a state at time t4 when the high gear stage is established by clutch-to-clutch shift, and FIG. 17 (d) shows that the engine speed Ne is increased by cranking by powering control of the first motor generator MG1. This is the state from time t5 to t6. (e) shows a state at time t8 when the engine rotation speed Ne and the MG1 rotation speed Nmg1 are synchronized and substantially synchronized.

  As described above, in the hybrid vehicle 10 of the present embodiment, when the first switching determination for switching from the EV single drive C1 on mode to the parallel high mode is made (YES in S2), the vehicle travels according to the first switching determination. It is predicted whether or not the second switching determination for switching to the parallel low mode is performed during the traveling mode switching control for switching the mode (S3). If it is determined that the second switching determination is likely to be performed, S4 and the subsequent steps are executed, and the engine 12 is started prior to the gear change, while the second switching determination may be performed. If it is determined that the engine speed is low, S8 and the following steps are executed, and the gear stage is changed prior to starting 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 or not the second switching determination is actually performed before the gear change is performed (S5). When the second switching determination is made, the parallel low mode is established by engaging the direct coupling clutch CS in S7 without changing the gear stage, so that the switching to the parallel low mode is performed in a short time. As a result, drivability performance such as driving force responsiveness is improved.

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

  In the above-described embodiment, the second motor generator MG2 is a gear train having a connection relation such that the second motor generator MG2 is disposed on an axis different from the axis of the first power transmission unit 24. For example, the second motor generator MG2 May be a gear train or the like that is connected on the same axis as the axis of the first power transmission unit 24.

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

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention is implemented in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

  DESCRIPTION OF SYMBOLS 10: Hybrid vehicle 12: Engine 16: Drive wheel 44: Mechanical transmission part 45: Connection member (output member) 46: Electric differential part 50: 2nd planetary gear mechanism (differential mechanism) 80: Electronic control unit 82 : Traveling 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 rotating element) S2: Sun gear (second rotating 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 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 the output member of the mechanical transmission, a second rotating element connected to the first rotating machine so that power can be transmitted, and a third rotating element functioning as an output element. An electric differential unit, wherein the differential state of the differential mechanism is controlled by controlling the operating state of the first rotating machine,
A second rotating machine coupled to the drive wheel to transmit power;
In a travel mode switching control device that travels while switching between the plurality of travel modes, the hybrid vehicle capable of traveling in a plurality of travel modes in which one of the engine operation, non-operation, and the gear stage is different,
A switching determination unit for performing switching determination of the traveling mode according to a predetermined traveling mode switching condition;
When the switching determination unit performs a first switching determination for switching between operation and non-operation of the engine and changing the gear stage, the travel mode switching control is performed in accordance with the first switching determination. A multiple switching prediction unit for predicting whether or not the switching determination unit performs the second switching determination to switch to another travel mode in which the gear position is changed while maintaining the switching of the engine operation and non-operation;
If it is predicted that the second switching determination will be made by the multiple switching prediction unit, the engine is switched between operating and non-operating prior to the change of the gear position, while the second switching determination is predicted. If not, a switching execution unit for changing the gear stage prior to switching between operation and non-operation of the engine;
And the switching execution unit, when it is predicted that the second switching determination will be made, before changing the gear stage after switching the operation of the engine, before the change of the gear stage, The switching determination unit determines whether or not the second switching determination is actually performed, and when the second switching determination is performed, the change of the gear stage is omitted and the switching to the another traveling mode is performed. A travel mode switching control device for a hybrid vehicle.

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