JP2023079685A - Hybrid vehicle control device - Google Patents

Abstract

A control device for a hybrid vehicle capable of reducing the amount of divergence between the driving force increased from the time of switching to Lo mode and the target driving force increasing toward the required driving force. When switching from high mode to low mode is requested, the driving force of the vehicle is predicted when the engine speed is increased at a predetermined rate of change after switching to low mode ( Step S2), when the difference between the required driving force and the predicted driving force is equal to or less than a predetermined difference and the vehicle speed is less than the predetermined vehicle speed, the disconnection mode is switched to the low mode (step S2). S8) If the difference between the required driving force and the predicted driving force is equal to or less than the predetermined difference and the vehicle speed is equal to or greater than the predetermined vehicle speed, the fixed speed mode is switched to the low mode, and the low mode is switched to. After that, the rotation speed of the engine is increased at a change rate smaller than a predetermined change rate (step S9). [Selection drawing] Fig. 9

Description

The present invention relates to a hybrid vehicle control device capable of setting a plurality of driving modes.

Patent Documents 1 and 2 disclose a first rotary element in which a first rotary element coupled with an engine, a second rotary element coupled with a first motor, and a third rotary element are differentially rotatably coupled. A second differential mechanism in which a differential mechanism, a fourth rotating element coupled to the driving wheels, a fifth rotating element coupled to the third rotating element, and a sixth rotating element are differentially rotatably coupled. a first clutch mechanism selectively connecting the first rotating element and the sixth rotating element; a second clutch mechanism selectively connecting the fifth rotating element and the sixth rotating element; A hybrid vehicle is described with a second motor communicatively coupled thereto.

These hybrid vehicles set the Lo mode in which the torque transmitted from the engine to the driving wheels is large by engaging the first clutch mechanism, and the torque is transmitted from the engine to the driving wheels by engaging the second clutch mechanism. By setting the Hi mode in which the torque applied is small, by engaging each clutch mechanism, setting the fixed speed mode in which the engine and the drive wheels are connected so that a predetermined gear ratio is obtained, and by releasing each clutch mechanism A decoupling mode can be set to interrupt transmission of torque between the engine and the drive wheels.

Patent Literature 2 describes a control device capable of increasing the driving force of the hybrid vehicle at low vehicle speeds and increasing the maximum vehicle speed of the hybrid vehicle configured as described above. Specifically, when the vehicle speed is higher than a predetermined vehicle speed, the fixed speed mode is set to enable running with the first motor and the second motor shut down, so that the first motor and the second motor are turned on. It is configured to suppress the generation of a large induced voltage due to being rotated together. By setting the fixed speed mode in this way, it is possible to prevent the maximum vehicle speed from being restricted for the purpose of protecting the first motor and the second motor.

Japanese Patent No. 6451524 Japanese Patent Application Laid-Open No. 2021-123309

In the hybrid vehicle described in Patent Document 1 and Patent Document 2 described above, when switching between the Lo mode and the Hi mode, the released clutch mechanism is engaged and the engaged clutch mechanism is released. Alternatively, disengage the engaged clutch mechanism and engage the disengaged clutch mechanism. That is, the Lo mode and the Hi mode are switched through either the fixed stage mode or the disconnection mode. Further, in the Lo mode, the torque transmitted from the engine to the drive wheels is large as described above, so it is preferable to set the Lo mode in a region where the required driving force is large.

Therefore, when the required driving force increases while the Hi mode is set and the vehicle is running, the mode is switched to the Lo mode. In addition, when switching to the Lo mode in this way, in order to control the engine speed so that the required driving force is satisfied and the fuel efficiency is good, the engine speed is further increased from the time of switching to the Lo mode. It may increase the number of revolutions. In such a case, it is difficult to increase the output torque of the engine because inertia torque corresponding to the rate of change of the engine speed is generated in the process of increasing the engine speed.

In order to suppress the delay in the increase in the driving force caused by the delay in the increase in the output torque of the engine, a torque equivalent to the inertia torque is added to the output torque required for the second motor. , the driving force can be increased following the target driving force that is increased toward the required driving force. However, when the second motor is outputting torque up to the upper limit torque that can be output from the second motor at the time of switching to the Lo mode, the torque equivalent to the inertia torque is added to the output torque required of the second motor. If it is not possible, the driving force cannot be increased to follow the target driving force, and the driver may feel uncomfortable.

The present invention has been made in view of the above technical problem, and aims to reduce the amount of divergence between the driving force to be increased after switching to the Lo mode and the target driving force that increases toward the required driving force. It is an object of the present invention to provide a control device for a hybrid vehicle capable of

In order to achieve the above object, the present invention uses two rotating elements: a rotating element to which an engine is connected, a rotating element to which a first motor is connected, and a rotating element to which a drive wheel is connected. a first differential mechanism configured such that three rotary elements, namely, a first rotary element, a second rotary element, and a third rotary element, perform a differential action; a rotary element coupled to the engine; A fourth rotating element which is the other rotating element of the rotating element to which the first motor is connected and the rotating element to which the driving wheel is connected, and a fifth rotating element which is connected to the third rotating element and a sixth rotating element, a second differential mechanism configured to perform a differential action, and either one of the first rotating element and the second rotating element. , a first engagement mechanism selectively connecting said sixth rotating element, and selectively connecting any pair of rotating elements of said fourth rotating element, said fifth rotating element and said sixth rotating element. and a second motor connected to the driving wheel or another driving wheel different from the driving wheel, the second engaging mechanism engaging the first engaging mechanism and the second engaging mechanism a low mode in which the first engagement mechanism is released and the second engagement mechanism is engaged in a high mode; and a fixed stage in which the first engagement mechanism and the second engagement mechanism are engaged. A control device for a hybrid vehicle configured to be able to set a running mode including a mode and a decoupled mode in which the first engagement mechanism and the second engagement mechanism are released, wherein the engine and the first motor , the second motor, the first engagement mechanism, and the second engagement mechanism, wherein the controller controls the switching to the low mode when the vehicle is running in the high mode. predicting the driving force of the hybrid vehicle when the number of revolutions of the engine is increased at a predetermined rate of change after switching to the low mode when switching of the driving mode is requested; and the predicted driving force of the hybrid vehicle is equal to or less than a predetermined difference and the vehicle speed is less than the predetermined vehicle speed, the disconnection mode is initiated. When the difference between the required driving force and the predicted driving force of the hybrid vehicle is equal to or less than the predetermined difference and the vehicle speed is equal to or higher than the predetermined vehicle speed, the fixed stage mode is switched to the low mode. In addition to switching to the low mode via the low mode, the rotation speed of the engine after switching to the low mode is increased at a rate of change smaller than the predetermined rate of change.

In the present invention, the controller switches from the high mode to the low mode when a difference between the required driving force and the predicted driving force of the hybrid vehicle is greater than the predetermined difference. You may prohibit the switching of driving modes.

According to the present invention, as described above, the driving force when the engine speed is increased after setting the low mode is predicted, and when the predicted driving force is smaller than the required driving force, the disconnected mode is set. By switching to the low mode via the low mode, or switching to the low mode via the fixed speed mode, and setting the rate of change in the engine speed after switching to the low mode to be small, the required drive power is reached after switching to the low mode. It is possible to reduce the amount of divergence between the target driving force and the actual driving force in the process of increasing the driving force. As a result, it is possible to prevent the driver from having a sense of incongruity such as being unable to obtain a feeling of acceleration.

1 is a skeleton diagram for explaining an example of a vehicle according to an embodiment of the invention; FIG. It is a block diagram for explaining the configuration of an electronic control unit (ECU). FIG. 4 is a nomographic chart for explaining an operating state in HV-Hi mode; FIG. 4 is a nomographic chart for explaining an operating state in HV-Lo mode; FIG. 4 is a nomographic chart for explaining an operating state in a direct connection mode; FIG. 4 is a nomographic chart for explaining the operating state in the disconnect mode; It is a figure which shows an example of the map for selecting driving modes. FIG. 3 is a diagram showing an example of a map for setting an operating point of an engine; FIG. 4 is a flow chart for explaining an example of control by the control device in the embodiment of the invention; 4 is a time chart showing changes in accelerator opening, driving force, engine speed, engine torque, and torque of the second motor 3 when the driving mode is switched via the disconnection mode; 4 is a time chart showing changes in accelerator opening, driving force, engine speed, engine torque, and second motor torque when the driving mode is switched via the direct connection mode and the rate of change of the engine speed is set small. .

An example of a vehicle Ve in an embodiment of the invention will be described with reference to FIG. A vehicle Ve shown in FIG. 1 includes an engine (ENG) 1 and a hybrid drive system (hereinafter simply referred to as drive system) 4 having two motors 2 and 3 . The driving device 4 is configured to drive front wheels (driving wheels) 5R and 5L. The engine 1 is a conventionally known gasoline engine, diesel engine, or the like, and outputs drive torque by burning a mixture of supplied fuel and air, and stops combustion of the mixture. That is, by stopping the supply of fuel, braking torque corresponding to friction torque, pumping loss, and the like can be output.

The first motor 2 is composed of a motor (namely, motor generator: MG1) that has a power generation function. , and the torque output by the second motor 3 can be added to the drive torque for running. Like the first motor 2, the second motor 3 can be composed of a motor (that is, a motor/generator: MG2) that has a power generation function. These first motor 2 and second motor 3 can be composed of, for example, AC motors such as permanent magnet type synchronous motors in which permanent magnets are attached to rotors. The motors 2 and 3 are electrically connected to a battery made up of a secondary battery such as a lithium ion battery and a power storage device B such as a capacitor. is supplied, and the electric power generated by the motors 2 and 3 can be charged to the power storage device B. As shown in FIG. Further, each of the motors 2 and 3 is configured such that electric power generated by one motor 2 (3) can be supplied to the other motor 3 (2) without the power storage device B being interposed.

A power split device 6 is connected to the engine 1 . This power splitting mechanism 6 splits the torque output by the engine 1 into the first motor 2 side and the output side. and a transmission unit 8 mainly having the function of changing the division ratio of .

The dividing portion 7 may have a configuration in which differential action is performed by three rotating elements, and a planetary gear mechanism can be employed. In the example shown in FIG. 1, it is configured by a single pinion type planetary gear mechanism (first differential mechanism). The divided portion 7 shown in FIG. 1 includes a sun gear 9, a ring gear 10 which is an internal gear arranged concentrically with respect to the sun gear 9, and a sun gear 9 arranged between the sun gear 9 and the ring gear 10. It has a pinion gear 11 meshing with a ring gear 10 and a carrier 12 that holds the pinion gear 11 so that it can rotate and revolve. It is configured.

The torque output by the engine 1 is input to the carrier 12 . Specifically, an output shaft 13 of the engine 1 is connected to an input shaft 14 of the power split device 6 , and the input shaft 14 is connected to the carrier 12 . Also, the first motor 2 is connected to the sun gear 9 . Instead of directly connecting the carrier 12 and the input shaft 14, the carrier 12 and the input shaft 14 may be connected via a transmission mechanism (not shown) such as a gear mechanism. Also, a mechanism (not shown) such as a damper mechanism or a torque converter may be arranged between the output shaft 13 and the input shaft 14 . Further, instead of connecting the first motor 2 and the sun gear 9 directly, the first motor 2 and the sun gear 9 may be connected via a transmission mechanism (not shown) such as a gear mechanism. These sun gear 9 and carrier 12 correspond to the "first rotating element" and "second rotating element" in the embodiments of the invention, and the ring gear 10 corresponds to the "third rotating element" in the embodiments of the invention. , and the dividing portion 7 corresponds to the "first differential mechanism" in the embodiment of the present invention.

The transmission unit 8 is configured by a single pinion type planetary gear mechanism. That is, as with the divided portion 7, the transmission portion 8 includes a sun gear 15, a ring gear 16 which is an internal gear concentrically arranged with respect to the sun gear 15, and a ring gear 16 between the sun gear 15 and the ring gear 16. It has a pinion gear 17 arranged and meshing with the sun gear 15 and the ring gear 16, and a carrier 18 holding the pinion gear 17 so as to rotate and revolve. Therefore, the transmission unit 8 is a differential mechanism (second differential mechanism) that performs a differential action with the three rotating elements of the sun gear 15, the ring gear 16, and the carrier . A ring gear 10 in the dividing portion 7 is connected to the sun gear 15 in the transmission portion 8 . An output gear 19 is connected to the ring gear 16 in the transmission section 8 . The ring gear 16 corresponds to the "fourth rotating element" in the embodiment of the invention, the sun gear 15 corresponds to the "fifth rotating element" in the embodiment of the invention, and the carrier 18 corresponds to the embodiment of the invention. , and the transmission unit 8 corresponds to the "second differential mechanism" in the embodiment of the present invention.

A Lo clutch mechanism (first engagement mechanism) CL_Lo is provided so that the split portion 7 and the transmission portion 8 form a compound planetary gear mechanism. The Lo clutch mechanism CL_Lo is for selectively connecting the carrier 18 in the transmission section 8 to the carrier 12 and the input shaft 14 in the split section 7, and is constructed by a friction type clutch mechanism or a meshing type clutch mechanism. can do. By engaging the Lo clutch mechanism CL_Lo, the carrier 12 in the divided portion 7 and the carrier 18 in the transmission portion 8 are connected to each other and serve as an input element, and the sun gear 9 in the divided portion 7 serves as a reaction force element. A compound planetary gear mechanism is formed in which the ring gear 16 in the portion 8 serves as an output element.

Furthermore, a Hi clutch mechanism (second engagement mechanism) CL_Hi is provided for integrating the entire transmission unit 8 . This Hi clutch mechanism CL_Hi is for connecting at least one pair of rotating elements such as connecting the carrier 18 and the ring gear 16 or the sun gear 15, or connecting the sun gear 15 and the ring gear 16 in the transmission section 8. Like the clutch mechanism CL_Lo, it can be configured by a friction type clutch mechanism or a meshing type clutch mechanism. In the example shown in FIG. 1 , the Hi clutch mechanism CL_Hi is configured to connect the carrier 18 and the ring gear 16 in the transmission section 8 . By engaging the Hi clutch mechanism CL_Hi, the rotary elements forming the transmission unit 8 rotate together. Therefore, the carrier 12 in the divided portion 7 serves as an input element, the sun gear 9 in the divided portion 7 serves as a reaction force element, and the ring gear 16 in the transmission portion 8 serves as an output element.

By engaging at least one of the Lo clutch mechanism CL_Lo and the Hi clutch mechanism CL_Hi, the engine 1 and the output gear 19 are coupled via the power split device 6 so that torque can be transmitted. Torque is transmitted from the output gear 19 to the front wheels 5R, 5L through the gear train portion. In the example shown in FIG. 1, a countershaft 20 is arranged in parallel with the rotation center axis of the engine 1, the divided portion 7, or the transmission portion 8. As shown in FIG. A driven gear 21 meshing with the output gear 19 is attached to the counter shaft 20 . A drive gear 22 is attached to the countershaft 20, and the drive gear 22 meshes with a ring gear 24 in a differential gear unit 23, which is a final reduction gear.

Further, the driven gear 21 is meshed with a drive gear 25 attached to the rotor shaft 3 a of the second motor 3 . Therefore, the driven gear 21 is configured to add the power or torque output from the second motor 3 to the power or torque output from the output gear 19 . The power or torque thus synthesized is output from the differential gear unit 23 to the left and right drive shafts 26, and the power or torque is transmitted to the front wheels 5R, 5L. The second motor 3 is connected to any rotating member provided in the torque transmission path between the output gear 19 and the driving wheels 5R and 5L, such as being connected to the drive gear 22 so as to be capable of transmitting torque. You may connect so that torque transmission is possible.

The driving device 4 shown in FIG. 1 is a one-way motor that is configured such that the output shaft 13 or the input shaft 14 can be fixed so that the driving torque output from the first motor 2 can be transmitted to the front wheels 5R and 5L. It has a clutch F. The one-way clutch F is configured to prevent the output shaft 13 and the input shaft 14 from rotating in a direction opposite to the direction in which they rotate when the engine 1 is driven.

Therefore, when the first motor 2 outputs the drive torque and the one-way clutch F is engaged, the one-way clutch F takes charge of reaction torque against the drive torque of the first motor 2. As a result, the first motor 2 drive torque of the first motor 2 is transmitted to the ring gear 16 from the . That is, by fixing the output shaft 13 or the input shaft 14 by the one-way clutch F, the carrier 12 in the divided portion 7 and the carrier 18 in the transmission portion 8 function as reaction force elements, and the sun gear 9 in the divided portion 7 functions as an input element. It is configured so that it can function as

The one-way clutch F is for generating reaction torque when the first motor 2 outputs drive torque. A regulating torque may be generated. In that case, the configuration is not limited to the configuration in which the output shaft 13 or the input shaft 14 is completely fixed, and the configuration may be such that the required reaction torque is applied to the output shaft 13 or the input shaft 14 while allowing relative rotation. good.

An electronic control unit (ECU) 27 is provided for controlling the engine 1, the motors 2 and 3, and the clutch mechanisms CL_Lo and CL_Hi. The ECU 27 corresponds to the "controller" in the embodiment of the invention, and is mainly composed of a microcomputer. FIG. 2 is a block diagram for explaining an example of the configuration of the ECU 27. As shown in FIG. In the example shown in FIG. 2, the ECU 27 is configured by the HV-ECU 28, the MG-ECU 29, the engine ECU 30, and the clutch ECU 31. As shown in FIG.

The HV-ECU 28 receives data input from various sensors mounted on the vehicle Ve, and based on the input data, pre-stored maps, calculation formulas, etc., the MG-ECU 29, the engine ECU 30, and the like. It is configured to output a command signal to the clutch ECU 31 . An example of data input to the HV-ECU 28 is shown in FIG. The rotation speed of the shaft 13 (engine rotation speed), the output rotation speed, which is the rotation speed of the ring gear 16 or the countershaft 20 in the transmission unit 8, the stroke amount of a movable member such as a piston constituting the Lo clutch mechanism CL_Lo, the Hi clutch mechanism CL_Hi The stroke amount of a movable member such as a piston that constitutes the Data such as the temperature of oil (ATF) for lubricating the engine is input to the HV-ECU .

The output torque of the first motor 2 and the output torque of the second motor 3 are obtained based on the data input to the HV-ECU 28, and the obtained data are output to the MG-ECU 29 as command signals. . Similarly, the output torque of the engine 1 is obtained based on the data input to the HV-ECU 28, and the obtained data is output to the engine ECU 30 as a command signal. Furthermore, based on data input to the HV-ECU 28, it is determined whether to engage or disengage the Lo clutch mechanism CL_Lo and the Hi clutch mechanism CL_Hi, and a command signal for the determined engaged state or disengaged state is output. Output to the clutch ECU 31 . When the Lo clutch mechanism CL_Lo and the Hi clutch mechanism CL_Hi are friction type clutch mechanisms, information on the torque capacity to be transmitted is transmitted from the HV-ECU 28 to the clutch ECU 31 in addition to the information on the engaged state and disengaged state. output to

The MG-ECU 29 obtains the current value to be supplied to each motor 2, 3 based on the data input from the HV-ECU 28 as described above, and outputs a command signal to each motor 2, 3. Since the motors 2 and 3 are AC motors, the command signal includes the frequency of the current to be generated by the inverter, the voltage value to be boosted by the converter, and the like.

Based on the data input from the HV-ECU 28 as described above, the engine ECU 30 outputs a current for determining the opening of the electronic throttle valve, a current for igniting the air-fuel mixture with an ignition device, an EGR (Exhaust Gas Recirculation) valve current for determining the opening of the intake valve and the current value for determining the opening of the exhaust valve, etc., and outputs a command signal to each valve and device. That is, the engine ECU 30 outputs an instruction signal for controlling the engine torque to each device that controls the output torque of the engine 1 .

The clutch ECU 31, based on the signals indicating the engagement state and the disengagement state of each of the clutch mechanisms CL_Lo and CL_Hi input from the HV-ECU 28 as described above, provides an illustration for establishing the engagement state and the disengagement state. A control amount for an actuator that does not operate is obtained, and a command signal is output to the actuator so as to achieve the control amount. It should be noted that the ECU 27 is not limited to a single ECU that performs all the controls in an integrated manner, and may be provided for each of the engine 1, each of the motors 2 and 3, and each of the clutch mechanisms CL_Lo and CL_Hi.

The drive device 4 described above can be operated in an HV drive mode in which torque is transmitted between the engine 1 and the front wheels 5L and 5R and driven by the first motor 2 and the second motor 3 without outputting drive torque from the engine 1. It is possible to set an EV running mode in which the vehicle runs while outputting torque. Furthermore, the HV drive mode includes an HV-Lo mode in which the torque transmitted from the engine 1 to the ring gear 16 (or the output gear 19) of the transmission section 8 is relatively large, and an HV-Hi mode in which the torque is relatively small. , and a direct connection mode (fixed speed mode) in which the torque of the engine 1 is transmitted to the ring gear 16 of the transmission section 8 as it is without changing.

Furthermore, the EV driving mode includes a dual mode in which torque is transmitted from the first motor 2 and the second motor 3 to the front wheels 5L and 5R for driving, and only the second motor 3 without outputting torque from the first motor 2. It is possible to set a single mode that outputs torque from Furthermore, the dual mode has an EV-Lo mode in which the amplification factor for amplifying the torque of the first motor 2 is relatively large, and an EV-Hi mode in which the amplification factor for amplifying the torque of the first motor 2 is smaller than the EV-Lo mode. Can be set. In the single mode, the torque is output only from the second motor 3 with the Lo clutch mechanism CL_Lo engaged, and the driving torque is output only from the second motor 3 with the Hi clutch mechanism CL_Hi engaged. Further, it is possible to output torque only from the second motor 3 while releasing the clutch mechanisms CL_Lo and CL_Hi. A mode in which the vehicle runs with the clutch mechanisms CL_Lo and CL_Hi released is referred to as a disconnection mode in the following description.

These running modes are set by controlling the engine 1, motors 2 and 3, and clutch mechanisms CL_Lo and CL_Hi. These driving modes, the Lo clutch mechanism CL_Lo, the Hi clutch mechanism CL_Hi, the engagement and disengagement states of the one-way clutch F, the operating states of the first motor 2 and the second motor 3, the engine 1 and the front wheels 5R in each driving mode. , 5L are shown in the table below. In the table, the "●" symbol indicates the engaged state, the "-" symbol indicates the disengaged state, and the "G" symbol means that the engine is operated mainly as a generator during driving. The "M" symbol means that the motor is mainly operated during driving, and blank spaces indicate that the motor and generator do not function, or that the first motor 2 or the second motor 3 is involved in driving. "ON" indicates a state in which the engine 1 and the front wheels 5R, 5L are transmitting torque, and "OFF" indicates a state in which the engine 1 and the front wheels 5R, 5L do not transmit torque. is shown.

3 to 6 show the rotation speed of each rotating element of the power split mechanism 6, the engine 1, and the motors 2 and 3 when the HV-Hi mode, HV-Lo mode, direct connection mode, and disconnection mode are set. is a nomographic chart for explaining the direction of the torque of . A nomographic chart is a diagram in which straight lines representing each rotating element in the power split mechanism 6 are drawn parallel to each other at intervals corresponding to the gear ratio, and the distance from a base line orthogonal to these straight lines is shown as the number of revolutions of each rotating element. , and the direction of the torque is indicated by an arrow on the straight line indicating each rotating element, and the magnitude of the torque is indicated by the length of the arrow.

As shown in FIG. 3, in the HV-Hi mode, the engine 1 outputs drive torque to engage the Hi clutch mechanism CL_Hi, and the first motor 2 outputs reaction torque. Further, as shown in FIG. 4, in the HV-Lo mode, the engine 1 outputs drive torque to engage the Lo clutch mechanism CL_Lo, and the first motor 2 outputs reaction torque.

The magnitude of torque transmitted from the engine 1 to the ring gear 16 differs between when the HV-Hi mode is set and when the HV-Lo mode is set. Specifically, if the output torque of the engine 1 is Te, the magnitude of the torque transmitted to the ring gear 16 when the HV-Lo mode is set is (1/(1-ρ1·ρ2)) Te. , HV-Hi mode, the magnitude of the torque transmitted to the ring gear 16 is (1/(1+ρ1))Te. Here, "ρ1" is the gear ratio of the dividing section 7 (ratio between the number of teeth of the ring gear 10 and the number of teeth of the sun gear 9), and "ρ2" is the gear ratio of the transmission section 8 (the number of teeth of the ring gear 16 and the sun gear 9). 15 teeth ratio). Note that ρ1 and ρ2 are values smaller than "1".

That is, when the HV-Lo mode is set, the torque, which is the ratio of the torque transmitted to the ring gear 16 (or the front wheels 5R and 5L) to the drive torque of the engine 1, is higher than when the HV-Hi mode is set. has a large division ratio (amplification ratio). The first clutch mechanism CL1 corresponds to the "first engagement mechanism" in the embodiment of the invention, and the second clutch mechanism CL2 corresponds to the "second engagement mechanism" in the embodiment of the invention. .

When a torque larger than the reaction torque is output from the first motor 2, the surplus torque acts to reduce the engine speed, and conversely, a torque smaller than the reaction torque. is output from the first motor 2, part of the engine torque acts to increase the engine speed. That is, by controlling the torque of the first motor 2, the engine speed can be controlled. In other words, the torque of the first motor 2 is controlled so that the engine speed becomes the target speed.

By outputting the reaction torque from the first motor 2 as described above, when the first motor 2 functions as a generator, part of the power of the engine 1 is converted into electrical energy by the first motor 2. be. Then, the power obtained by removing the power converted into electric energy by the first motor 2 from the power of the engine 1 is transmitted to the ring gear 16 in the transmission section 8 . Then, when the torque transmitted from the ring gear 16 to the front wheels 5R, 5L is smaller than the torque to be transmitted to the front wheels 5R, 5L in order to output the required driving force, the second motor 3 outputs the insufficient torque. to output That is, the second motor 3 outputs assist torque for satisfying the required driving force. The electric power converted by the first motor 2 may be supplied to the second motor 3 to drive the second motor 3, or may be supplied to the power storage device B to increase the remaining charge of the power storage device B. You may

In the direct connection mode, the clutch mechanisms CL_Lo and CL_Hi are engaged so that the rotary elements in the power split mechanism 6 rotate at the same speed as shown in FIG. In other words, the differential rotation of the engine 1, the first motor 2, and the output member (output gear 19) is restricted. Therefore, all of the power of engine 1 is output from power split device 6 . Therefore, part of the power of the engine 1 is not converted into electrical energy by the first motor 2 or the second motor 3, and loss caused by factors such as Joule loss that occurs when converting into electrical energy can be suppressed. , the power transmission efficiency can be improved.

In the disconnect mode, the transmission of torque between the engine 1 and the front wheels 5R, 5L via the power split device 6 is interrupted by releasing the clutch mechanisms CL_Lo, CL_Hi. Therefore, in the disconnected mode, the engine 1 and the first motor 2 can be stopped as indicated by solid lines in FIG. That is, each rotating element constituting the split portion 7 and the sun gear 15 in the transmission portion 8 stop, the ring gear 16 rotates at a rotational speed corresponding to the vehicle speed, and the carrier 18 rotates the gear ratio of the transmission portion 8 and the ring gear 16. and the number of revolutions corresponding to the number of revolutions.

Note that in the disconnection mode, the engine 1 may be driven according to various conditions, such as for warming up the engine 1, for example. Specifically, the Hi clutch mechanism CL_Hi may be released from the time when the HV-Hi mode was set, and the engine 1 and the first motor 2 may be rotated independently as indicated by the broken line. In that case, the ring gear 10 and the sun gear 15 idle at a rotation speed corresponding to the rotation speeds of the engine 1 and the first motor 2 . Therefore, even when the engine 1 is driven as described above, the engine torque is not transmitted to the drive wheels 5R, 5L by disengaging the clutch mechanisms CL_Lo, CL_Hi.

The above HV-Lo mode, direct connection mode, and HV-Hi mode are selected based on a map stored in the HV-ECU 28 in advance. An example of such a map is shown in FIG. 7, and is constructed such that the driving mode is selected according to the driving point of the vehicle Ve. The horizontal axis represents the vehicle speed, the vertical axis represents the required driving force, and the regions where EV driving is possible are hatched.

Specifically, as shown in FIG. 7, the HV-Lo mode is selected when the vehicle speed is relatively low or when the required driving force is relatively large, and when the vehicle speed is relatively high and the required driving force is relatively small. In addition, when the HV-Hi mode is selected and the driving point of the vehicle Ve is between the regions for setting the HV-Lo mode and the HV-Hi mode, the direct connection mode is selected. there is

Further, the HV-Lo mode, the direct connection mode, and the HV-Hi mode are configured to be switched when the operating point crosses each line shown in FIG. Specifically, when the operating point crosses the "Lo←Fix" line in FIG. It is configured to switch, and when the operating point crosses the "Lo → Fix" line from left to right or from top to bottom, it switches from HV-Lo mode to direct mode. is configured to Similarly, when the operating point crosses the "Fix←Hi" line in Fig. 7 from the right side to the left side or from the bottom side to the top side, the HV-Hi mode is switched to the direct connection mode. configured to switch from direct connection mode to HV-Hi mode when the operating point crosses the "Fix→Hi" line from left to right or from top to bottom. It is

Therefore, when driving with the HV-Hi mode set and the driving force required increases and the driving point shifts from the operating point labeled A to the operating point labeled B in FIG. Switch to Lo mode.

The HV-Lo mode and HV-Hi mode described above function as a continuously variable transmission capable of continuously changing the rotation speed of the engine 1 by controlling the rotation speed of the first motor 2 . Therefore, as the required driving force increases as described above, the target rotation speed of the engine 1 changes so that the operating point of the engine 1 becomes an operating point with good fuel efficiency. FIG. 8 shows an example of a map for determining the operating points of the engine 1. As shown in FIG. In FIG. 8, the horizontal axis represents the engine speed Ne, and the vertical axis represents the engine torque Te. The dashed line is the output power Preq1 required of the engine 1 during the HV-Hi mode, and the dashed line is the output power of the engine 1 required as the required driving force increases. Preq2.

When the required driving force increases as described above, the output power required of the engine 1 also increases. Therefore, when the power required for the engine 1 is the power corresponding to Preq1 in FIG. is the target engine speed, and in this state, when the required driving force increases and the power required of the engine 1 increases to the power corresponding to Preq2 in FIG. is the target rotation speed. That is, the target rotation speed of the engine 1 increases as the required driving force increases.

When switching from the HV-Hi mode to the HV-Lo mode as described above, after the Lo clutch mechanism CL_Lo is engaged, the Hi clutch mechanism CL_Hi is released, or after the Hi clutch mechanism CL_Hi is released, the Lo clutch mechanism Engage CL_Lo. That is, the driving mode can be switched through either the direct connection mode or the disconnected mode.

When switching from the HV-Hi mode to the HV-Lo mode via the direct coupling mode, after the rotational speed difference between the carrier 12 and the carrier 18 is reduced to a predetermined difference in order to engage the Lo clutch mechanism CL_Lo, Engage the Lo clutch mechanism CL_Lo. Then, the Hi clutch mechanism CL_Hi is released. After switching to the HV-Lo mode, the engine speed is increased so that the engine speed follows the target speed.

Further, when switching from the HV-Hi mode to the HV-Lo mode via the disconnection mode, by releasing the Hi clutch mechanism CL_Hi, as shown by the dashed line in FIG. can be increased. Further, the first motor 2 can be controlled so that the rotational speed difference between the carrier 12 and the carrier 18 is a predetermined difference. Therefore, as the engine speed increases, the speed difference between the carrier 12 and the carrier 18 can be made a predetermined difference, and at that time, the HV-Lo mode is set by engaging the Lo clutch mechanism CL_Lo. be able to. After switching to the HV-Lo mode, the engine speed is increased so that the engine speed follows the target speed.

As described above, when the driving force Freq required for the vehicle Ve (hereinafter referred to as the required driving force) Freq is increased, a provisional target driving force Ftgt is determined for each predetermined time to be increased toward the required driving force Freq. Next, the power Preq required for the engine 1 is obtained according to the provisional target driving force Ftgt. That is, the power obtained by multiplying the provisional target driving force Ftgt by the vehicle speed is obtained as the required power Preq of the engine 1 .

Then, the throttle opening, the fuel injection amount, and the like are controlled so that the engine 1 generates the required power Preq obtained as described above. The rotation speed of the first motor 2 is controlled so that the engine rotation speed changes at a predetermined rate of change. Specifically, it depends on the durability of the components of the engine 1 and the power split mechanism 6, the maximum rate of change predetermined by sensory tests, etc., or the magnitude of the required driving force Freq (or provisional target driving force Ftgt). The first motor 2 is controlled so as to achieve a predetermined rate of change based on. In that case, the output torque of the first motor 2 is controlled by feeding back the deviation between the target rotation speed and the actual rotation speed of the first motor 2 . That is, when the target rotation speed of the first motor 2 is lower than the actual rotation speed, the torque of the first motor 2 is increased so that the target rotation speed of the first motor 2 is lower than the actual rotation speed. is also high, the torque of the first motor 2 is reduced.

Therefore, when increasing the engine speed for which the HV-Lo mode is set, mainly the torque of the first motor 2 is reduced by the inertia torque corresponding to the rate of increase of the engine speed. As a result, the engine speed increases, so the torque output from the engine 1 is obtained by subtracting the inertia torque from the torque corresponding to the required power Preq of the engine 1 and the current engine speed. That is, the output torque of the engine 1 required to satisfy the provisional target driving force Ftgt and the torque actually output from the engine 1 diverge. Therefore, in the process of increasing the engine speed after switching to the HV-Lo mode as described above, the assist torque is output from the second motor 3 in order to satisfy the provisional target driving force Ftgt. Similarly, during the transitional period of switching the driving mode, the second motor 3 outputs the assist torque so as to suppress the divergence between the actual driving force Fcur and the provisional target driving force Ftgt.

On the other hand, when the power output from the power storage device B is limited due to factors such as the temperature and SOC of the power storage device B, or when the torque output from the second motor 3 is limited due to the temperature of the second motor 3 If the torque is output from the second motor 3 up to the torque that can be output from the second motor 3 after switching to the HV-Lo mode, such as when switching to the HV-Lo mode as described above. In the subsequent process of increasing the engine speed, the second motor 3 may not be able to output the assist torque for suppressing the divergence between the actual driving force Fcur and the provisional target driving force Ftgt. In such a case, the actual driving force Fcur until the driving force Freq requested by the driver is output is excessively lower than the driving force intended by the driver, or the second motor 3 is sufficiently low. is smaller than when a large assist torque can be output.

Therefore, even if the second motor 3 cannot output an assist torque capable of satisfying the provisional target driving force Ftgt, the control device according to the embodiment of the present invention provides the provisional target driving force after switching to the HV-Lo mode. It is configured to perform switching between driving modes that can reduce the amount of divergence between Ftgt and the actual driving force Fcur. A flow chart for explaining an example of the control is shown in FIG.

The control example shown in FIG. 9 is repeatedly executed while driving with the HV-Hi mode set. ). This step S1 can be determined based on the driving point of the vehicle Ve determined based on the required driving force Freq and the vehicle speed and the map for setting the running mode shown in FIG.

If there is no request to switch to the HV-Lo mode, such as when maintaining the HV-Hi mode, when there is a request to switch to the fixed gear mode, or when there is a request to switch to the EV driving mode, then in step S1 If the determination is negative, this routine is temporarily terminated. Conversely, if affirmative determination is made in step S1 because there is a request to switch to the HV-Lo mode, switching to the HV-Lo mode in the case of switching to the HV-Lo mode via the direct mode is performed. Then, the predicted driving force Fpre is calculated (step S2). This step S2 obtains the driving force that can actually be output at predetermined time intervals from the time when the mode is switched to the HV-Lo mode. Specifically, the output torque of the second motor 3 is a predetermined torque corresponding to the current accelerator opening, the predetermined change rate of the engine speed, the state of the power storage device B and the second motor 3. On the condition that it is limited to Tm, the maximum driving force for each predetermined time is obtained based on the following equation (1).
Fpre=((Te_tgt-Tiner)/(1-ρ1・ρ2)+Tm×γre)×γdiff/R (1)

Note that Te_tgt in the above equation is the target torque of the engine 1 . In order to obtain the target torque of the engine 1, first, the accelerator opening to be reached is predicted based on the current accelerator opening and its rate of change, and then the predicted accelerator opening and the current vehicle speed are calculated. Obtain the predicted required driving force Freq. Then, the target torque of the engine 1 can be obtained from the required power req of the engine 1 based on the predicted required driving force Freq and vehicle speed and the optimum fuel consumption line. Further, Tiner is the inertia torque of the engine 1 when the engine speed is changed at a predetermined rate of change, γre is the gear ratio between the driven gear 21 and the drive gear 25, and γdiff is the drive gear from the countershaft 20. It is the reduction ratio of the gear leading to the shaft 26, and R is the tire radius of the front wheels 5R and 5L.

After step S2, it is determined whether or not the predicted required driving force Freq is greater than the predicted driving force Fpre (step S3). This step S3 is a step for determining whether or not the driving force cannot be increased to follow the provisional target driving force Ftgt. That is, when the predicted required driving force Freq is smaller than the predicted driving force Fpre, the torque of the second motor 3 is controlled to increase the actual driving force Fcur following the provisional target driving force Ftgt. can be made Therefore, when the predicted required driving force Freq is smaller than the predicted driving force Fpre and thus the negative determination is made in step S3, the HV-Lo mode is switched via the direct connection mode, as in the normal switching of the driving mode. (step S4), and this routine is temporarily terminated. In that case, the rotational speed of the first motor 2 is controlled so that the engine rotational speed after switching to the HV-Lo mode changes at a predetermined rate of change.

On the contrary, when the predicted required driving force Freq is larger than the predicted driving force Fpre and thus the determination in step S3 is affirmative, the provisional target driving force Ftgt is followed after switching to the HV-Lo mode. driving force cannot be changed by Therefore, it is determined whether or not the difference (Ftgt-Fpre) between the predicted required driving force Freq and the predicted driving force Fpre is less than a predetermined difference (step S5). Note that the predetermined difference in step S5 is not limited to a fixed value, and may be a variable value determined according to the vehicle speed or the magnitude of the required driving force Freq.

If the difference between the predicted required driving force Freq and the predicted driving force Fpre is equal to or greater than the predetermined difference and the result is negative in step S5, the running mode is switched in steps S8 and S9, which will be described later. Even so, there is a possibility that the driver will feel a sense of incompatibility such as not being able to obtain a sufficient feeling of acceleration. Therefore, if the determination in step S5 is negative, the switching request is canceled (prohibited) (step S6), and this routine is terminated. That is, the HV-Hi mode is maintained.

Conversely, if the difference between the predicted required driving force Freq and the predicted driving force Fpre is less than the predetermined difference and the result of step S5 is affirmative, the provisional target driving force Ftgt and the actual driving force Mode switching control is performed to reduce the difference from Fcur. Specifically, the engine speed change rate (Ne rate) after switching the driving mode via the disconnection mode or after setting the HV-Lo mode via the direct connection mode is set to be smaller than the predetermined rate of change. Switch modes.

As described above, the direct connection mode is a mode in which the power split device 6 rotates integrally, so there is a proportional relationship between the vehicle speed and the engine speed. is the number of revolutions corresponding to the vehicle speed. On the other hand, the decoupled mode can be switched to HV-Lo mode while changing the engine speed independently of the vehicle speed. Therefore, at low vehicle speeds, if the driving mode is switched via the direct connection mode, there is a possibility that the difference between the engine speed when the HV-Lo mode is set and the target engine speed Netgt corresponding to the required power Preq will increase. In such a case, if the rate of change of the engine speed is set to be smaller than the predetermined rate of change, it will take longer for the engine speed to reach the target speed Netgt. As a result, there is a possibility that the period from the time of switching to the HV-Lo mode to the output of the required driving force Freq will become longer.

Therefore, if the difference between the predicted required driving force Freq and the predicted driving force Fpre is less than the predetermined difference and the result of step S5 is affirmative, it is determined whether the vehicle speed is less than the predetermined vehicle speed. (Step S7). If the vehicle speed is switched to the HV-Lo mode via the direct coupling mode, the target engine speed is set at a rate of change smaller than the predetermined rate within an allowable period from the time of switching to the HV-Lo mode. It is possible to set a vehicle speed that can be increased up to the engine speed Netgt.

If the vehicle speed is less than the predetermined vehicle speed and the determination in step S7 is affirmative, the running mode is switched via the disconnection mode (step S8), and this routine ends. Conversely, if the vehicle speed is equal to or higher than the predetermined vehicle speed and thus the determination in step S7 is negative, the rate of change in the engine speed through the direct connection mode and after setting the HV-Lo mode is reduced to the predetermined rate of change. Then, the running mode is switched to a value smaller than , (step S9), and this routine is once terminated. Note that the rate of change in the engine speed in step S9 may be determined so that the driving force difference between the provisional target driving force Ftgt and the predicted driving force Fpre becomes an allowable difference, and is changed according to the magnitude of the driving force difference. It may be a predetermined fixed value.

FIG. 10 shows the accelerator opening, the driving force, the engine speed, the engine torque, and the torque of the second motor (MG2) 3 when the driving mode is switched via the disconnection mode by executing step S8. It is a time chart showing changes. In the example shown in FIG. 10, the vehicle is running with the HV-Hi mode set at time t0, and the accelerator opening increases at time t1. Along with this, the engine speed, the engine torque, and the torque of the second motor 3 begin to increase, and as a result, the driving force begins to increase. The second motor 3 is increased in order to make up for the shortage of the driving force due to the increase in the engine speed.

The required driving force Freq corresponding to the accelerator opening from time t1 to time t2 increases to the driving force required to switch to the HV-Lo mode. Therefore, affirmative determination is made in step S1 in FIG. 9 before time t2, and the predicted driving force Fpre is obtained. In the example shown in FIG. 10, the predicted driving force Fpre is smaller than the predicted required driving force Freq, the driving force difference is less than the predetermined difference, and the vehicle speed is less than the predetermined vehicle speed. Therefore, switching to the HV-Lo mode via the disconnection mode is performed at time t2.

Therefore, at time t2, the Hi clutch mechanism CL_Hi is released and switched to the disconnection mode. As a result, since the reaction force in the direction of decreasing the engine speed does not act, the torque generated in the engine 1 increases the engine speed. The dashed line shows the change in engine speed when switching to HV-Lo mode via direct connection mode. can be increased to

By switching to the disconnection mode as described above, torque is not transmitted from the engine 1 to the front wheels 5R and 5L, so that the front wheels 5R and 5L are driven only by the torque output from the second motor 3. Therefore, torque corresponding to the provisional target driving force Ftgt is required for the second motor 3, so the torque of the second motor 3 is increased. On the other hand, even if the torque of the second motor 3 is increased to the maximum torque at time t2, the provisional target driving force Ftgt cannot be satisfied. The force Fcur (solid line) is small, and the drive force is stagnant during the period in which the disconnection mode is set.

At time t3, the rotational speeds of the carrier 12 and the carrier 18 match, so that the Lo clutch mechanism CL_Lo is engaged and the HV-Lo mode is set. As a result, part of the engine torque is transmitted to the front wheels 5R, 5L, and the actual driving force Fcur begins to increase. In the example shown in FIG. 10, the accelerator opening is kept constant from time t3.

From time t3, the engine speed increases toward the target speed of the engine 1 based on the required power Preq of the engine 1 corresponding to the accelerator opening and the vehicle speed and the optimum fuel consumption line. If the period (period between t4 and t3) during which the engine speed is increased to the target speed is the same as when the running mode is switched via the direct connection mode, the increase rate of the engine speed becomes small. By switching the driving mode via the disconnection mode as described above, the engine speed at the time of switching to the HV-Lo mode is set to a higher speed than switching the driving mode via the HV-Lo mode. because it can

Therefore, it is possible to reduce the inertia torque in the process of increasing the engine speed toward the target speed. The torque obtained by reducing the inertia torque becomes larger when the running mode is switched via the disconnected mode (solid line) than when the running mode is switched via the direct connection mode (chain line). Therefore, it is possible to reduce the amount of deviation between the provisional target driving force Ftgt and the actual driving force Fcur after switching to the HV-Lo mode, thereby preventing the driver from having a sense of discomfort such as not being able to feel acceleration. can. In the example shown in FIG. 10, when the engine speed increases to the target speed, the actual driving force Fcur increases to the required driving force Freq.

FIG. 11 shows the accelerator opening, driving force, engine speed, engine torque, and torque of the second motor (MG2) 3 when the driving mode is switched via the direct mode by executing step S9. It is a time chart showing changes. In the example shown in FIG. 11, as in the example shown in FIG. 10, the vehicle is running with the HV-Hi mode set at time t10, and the accelerator opening increases at time t11. Along with this, the engine speed, the engine torque, and the torque of the second motor 3 begin to increase, and as a result, the driving force begins to increase. The second motor 3 is increased in order to make up for the shortage of the driving force due to the increase in the engine speed.

Between time t11 and time t12, the required driving force Freq corresponding to the accelerator opening increases to the driving force required to switch to the HV-Lo mode. Therefore, before time t12, step S1 in FIG. 9 is affirmatively determined, and the predicted driving force Fpre is obtained. In the example shown in FIG. 11, the predicted driving force Fpre is smaller than the predicted required driving force Freq, the driving force difference is less than the predetermined difference, and the vehicle speed is equal to or higher than the predetermined vehicle speed. Therefore, switching to the HV-Lo mode via the direct connection mode is performed at time t12.

Therefore, at time t12, the Lo clutch mechanism CL_Lo is engaged to switch to the direct connection mode. In the direct connection mode, the torque of the engine 1 can be transmitted to the front wheels 5R and 5L, so unlike the example shown in FIG. , and the actual drive force Fcur continues to increase.

At time t13, the Hi clutch mechanism CL_Hi is released and the HV-Lo mode is set. Therefore, from time t13, the engine speed increases toward the target speed of the engine 1 based on the required power Preq of the engine 1 corresponding to the accelerator opening and the vehicle speed and the optimum fuel consumption line. Specifically, when sufficient assist torque can be output from the second motor 3 (dashed line), the engine speed increases to the target speed at time t14. , the engine speed increases to the target speed. In other words, the increase rate of the engine speed after the HV-Lo mode is set is made smaller than when the second motor 3 can output sufficient assist torque. In the example shown in FIG. 11, the accelerator opening is kept constant from time t13.

Therefore, although the period until the engine speed increases to the target speed becomes longer, the inertia torque can be reduced in the process of increasing the engine speed toward the target speed. As a result, the torque output from the engine 1, that is, the torque obtained by subtracting the inertia torque from the torque generated by the engine 1 (dashed line) is higher than the engine rotation speed when the increase rate of the engine speed is large (chain line). When the increase rate of the number is decreased (solid line), it becomes larger. Therefore, it is possible to reduce the amount of deviation between the provisional target driving force Ftgt and the actual driving force Fcur after switching to the HV-Lo mode, thereby preventing the driver from feeling discomfort such as not being able to feel acceleration. can. In the example shown in FIG. 11, although the period until the actual driving force Fcur increases to the required driving force Freq, the difference (Ftgt-Fpre) between the provisional target driving force Ftgt and the predicted driving force Fpre is allowed. Only when the difference is less than the possible predetermined difference (when the determination in step S5 is affirmative), the increase rate of the engine speed is set to a small value. can suppress the feeling of discomfort.

Considering the inertia torque caused by increasing the engine speed after setting the HV-Lo mode as described above and the torque that can be output from the second motor 3, the driving force after setting the HV-Lo mode is If the predicted driving force is smaller than the required driving force, it switches to HV-Lo mode via disconnection mode, or switches to HV-Lo mode via direct connection mode and switches to HV-Lo mode. By setting the change rate of the engine speed after switching to a small value, it is possible to reduce the amount of divergence between the provisional target driving force and the actual driving force after switching to the HV-Lo mode. As a result, it is possible to prevent the driver from having a sense of incongruity such as being unable to obtain a feeling of acceleration.

The hybrid vehicle according to the embodiment of the present invention is not limited to the configuration described above. For example, the engine and drive wheels are connected to one differential mechanism, and the first motor is connected to the other differential mechanism. Alternatively, the first motor and drive wheels may be connected to one differential mechanism, and the engine may be connected to the other differential mechanism. Moreover, the second motor may be connected so as to transmit torque not only to the drive wheels to which torque is transmitted from the engine, but also to other drive wheels (for example, rear wheels).

1 engine 2, 3 motor 4 driving device 5R, 5L front wheel (driving wheel)
6 Power Split Mechanism 7 Split Part 8 Transmission Part 9, 15 Sun Gear 10, 16, 24 Ring Gear 12, 18 Carrier 19 Output Gear 27 Electronic Control Unit (ECU)
B Power storage device CL_Lo, CL_Hi Clutch mechanism Ve Vehicle

Claims (2)

a first rotating element and a second rotating element, which are two rotating elements selected from a rotating element to which an engine is connected, a rotating element to which a first motor is connected, and a rotating element to which a drive wheel is connected; a first differential mechanism configured such that the three rotary elements perform a differential action with the three rotary elements;
a fourth rotating element that is the other rotating element among the rotating element to which the engine is connected, the rotating element to which the first motor is connected, and the rotating element to which the driving wheel is connected; a second differential mechanism configured so that three rotary elements, that is, a fifth rotary element connected to the rotary element and a sixth rotary element, perform a differential action;
a first engaging mechanism that selectively couples one of the first rotating element and the second rotating element and the sixth rotating element;
a second engagement mechanism that selectively couples any one pair of the fourth rotating element, the fifth rotating element, and the sixth rotating element;
a second motor connected to the drive wheel or another drive wheel different from the drive wheel,
a low mode in which the first engagement mechanism is engaged and the second engagement mechanism is released; a high mode in which the first engagement mechanism is released and the second engagement mechanism is engaged; A running mode can be set between a fixed stage mode in which the first engagement mechanism and the second engagement mechanism are engaged and a separated mode in which the first engagement mechanism and the second engagement mechanism are released. In the configured hybrid vehicle control device,
a controller that controls the engine, the first motor, the second motor, the first engagement mechanism, and the second engagement mechanism;
The controller is
When switching the running mode to the low mode is requested while running with the high mode set, the engine speed is changed at a predetermined rate of change after switching to the low mode. Predicting the driving force of the hybrid vehicle when increased by
When the difference between the required driving force of the hybrid vehicle and the predicted driving force of the hybrid vehicle is equal to or less than a predetermined difference and the vehicle speed is less than the predetermined vehicle speed, the disconnection is performed. switch to said low mode via a mode;
When the difference between the required driving force and the predicted driving force of the hybrid vehicle is equal to or less than the predetermined difference and the vehicle speed is equal to or greater than the predetermined vehicle speed, the mode is switched to the low mode via the fixed stage mode. and increasing the rotation speed of the engine after being switched to the low mode at a rate of change smaller than the predetermined rate of change. In the hybrid vehicle control device according to claim 1,
The controller is
switching of the driving mode from the high mode to the low mode is prohibited when a difference between the required driving force and the predicted driving force of the hybrid vehicle is larger than the predetermined difference. A control device for a hybrid vehicle.

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