Hybrid vehicle control device

Abstract

To achieve both enhancement of startup responsiveness of an engine and reduction of shock when switching from EV travel in which the engine is stopped by engaging a clutch mechanism, to HV travel in which the engine is driven.SOLUTION: A control device of a hybrid vehicle comprises a power division mechanism in which an engine, a first motor and driving wheels differentially rotate, a second motor which is connected between the power division mechanism and the driving wheels, and a clutch mechanism which selectively interrupts transmission of torque between the power division mechanism and the driving wheels. Engagement of the clutch mechanism is started, if a prescribed parameter changes by exceeding a first prescribed value in a state where an EV travel mode, in which the clutch mechanism is released, is set (step S4), and the mode is switched to an HV travel mode in which torque of the engine is transmitted to the driving wheels for travel, if a prescribed parameter changes by further exceeding a second prescribed value having a prescribed difference from the first prescribed value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device for a hybrid vehicle that can switch between an EV driving mode in which the vehicle runs solely on motor power, and an HV driving mode in which the vehicle runs on both engine and motor power. [Background technology]

[0002] Patent Document 1 describes a control device for a hybrid vehicle including a power split device in which an engine, a first motor, and an output shaft are connected to each other so as to rotate differentially, a second motor connected to the output shaft, and a clutch mechanism that selectively interrupts torque transmission between the output element of the power split device and the output shaft. This hybrid vehicle is configured to be able to switch between EV running, in which the clutch mechanism is disengaged and only the second motor is driven, and series-parallel running, in which the clutch mechanism is engaged and the engine and the second motor are driven. That is, the hybrid vehicle is configured to switch from EV running to series-parallel running by switching the clutch mechanism from a disengaged state to an engaged state. The control device for controlling the clutch mechanism is configured to increase the slip amount during the engagement transition of the clutch mechanism as the required driving force increases when switching from EV running to series-parallel running. Furthermore, the control device is configured to start engaging the clutch mechanism at a state where the differential rotation speed between the driving-side rotating element and the driven-side rotating element is greater as the required driving force increases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-126322 Summary of the Invention [Problem to be solved by the invention]

[0004] The hybrid vehicle control device described in Patent Document 1 gradually reduces the slippage of the clutch mechanism to fully engage the clutch mechanism when switching from EV driving to series-parallel driving. Therefore, there is an unavoidable delay corresponding to the time the clutch mechanism is engaged before switching from EV driving to series-parallel driving. Furthermore, for example, in a configuration in which the engine is motored (cranked) by outputting torque from the first motor while the clutch mechanism is engaged, the engine is started after the clutch mechanism is engaged, which may result in poor engine start-up response. In contrast, if the clutch mechanism is suddenly engaged when the differential rotational speed between the driving-side rotating element and the driven-side rotating element that make up the clutch mechanism is large in order to quickly switch driving modes and improve engine start-up response, the engagement of the clutch mechanism causes a sudden change in the rotational speed of the first motor, which may transmit inertia torque corresponding to the rate of change in the rotational speed of the first motor to the drive wheels, resulting in a shock.

[0005] The present invention has been made with a focus on the above-mentioned technical problems, and aims to provide a control device for a hybrid vehicle that can achieve both improved engine start-up responsiveness and reduced shock when switching from EV driving, in which the engine is stopped, to HV driving, in which the engine is driven, by engaging a clutch mechanism. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a vehicle powertrain comprising: a power split mechanism in which at least three rotation elements, a first rotation element connected to an engine, a second rotation element connected to a first motor, and a third rotation element connected to drive wheels, rotate differentially; a second motor connected between the third rotation element and the drive wheels or to a drive wheel other than the drive wheels; and a clutch mechanism that selectively interrupts transmission of torque between the engine and the drive wheels via the power split mechanism, and when the clutch mechanism is released, the second motor is connected to the drive wheels. Before connecting to the Drive The second motor is connected to the wheel or the other drive wheel.a control device for a hybrid vehicle capable of switching between an EV driving mode in which torque is transmitted from the engine to the drive wheels to drive the vehicle, and an HV driving mode in which the clutch mechanism is engaged and torque is transmitted from the engine to the drive wheels to drive the vehicle, the control device comprising: a controller for controlling the clutch mechanism; an engagement determination unit that initiates engagement of the clutch mechanism when a predetermined parameter changes beyond a first predetermined value while the EV driving mode is set; and a mode determination unit that determines switching from the EV driving mode to the HV driving mode when the predetermined parameter changes beyond a second predetermined value that is a predetermined difference from the first predetermined value. the vehicle further includes a power storage device that supplies power to the second motor, the parameters include a remaining charge of the power storage device, and the first predetermined value is set higher than the second predetermined value. It is characterized by the presence of

[0008] In the present invention, the predetermined difference may be set so that when the hybrid vehicle is driven in a predetermined operating state in the EV driving mode, the time it takes for the parameter to change from the first predetermined value to the second predetermined value is longer than the time it takes to engage the clutch mechanism. [Effects of the Invention]

[0009] According to the present invention, in an EV driving mode in which the clutch mechanism is disengaged to interrupt torque transmission between the engine and the drive wheels via the power split mechanism and torque is output from a second motor provided on the output side of the clutch mechanism, engagement of the clutch mechanism is initiated when a predetermined parameter changes beyond a predetermined first predetermined value. A determination is made to switch from the EV driving mode to the HV driving mode when the predetermined parameter further changes beyond a second predetermined value that is a predetermined difference from the first predetermined value. Therefore, engagement of the clutch mechanism can be initiated before the switch to the HV driving mode is established. As a result, time to engage the clutch mechanism can be secured. Therefore, after the decision to switch to the HV driving mode is made, it is only necessary to start the engine. This shortens the time from when the decision to switch to the HV driving mode is made until the engine starts and generates driving torque, thereby improving engine start responsiveness. Furthermore, because time to engage the clutch mechanism can be secured, the clutch mechanism can be synchronized with relatively high precision. As a result, inertia torque generated when the clutch mechanism is engaged can be suppressed, thereby suppressing shock associated with clutch mechanism engagement. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a skeleton diagram illustrating an example of a hybrid vehicle according to an embodiment of the present invention. [Figure 2] 6A and 6B are nomographic diagrams illustrating the changes in the rotation speed of the engine, the first motor, and the output gear during the transition period from EV driving mode to HV driving mode, where (a) is the EV driving mode, (b) is the synchronization transition period of the clutch mechanism, (c) is the engagement of the clutch mechanism, and (d) is the engine start-up nomographic diagram. [Figure 3] 4 is a flowchart illustrating an example of control executed by a control device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described based on the embodiments shown in the drawings. Note that the embodiments described below are merely examples of specific embodiments of the present invention and are not intended to limit the present invention.

[0012] FIG. 1 shows an example of a hybrid vehicle (hereinafter referred to as a vehicle) in an embodiment of the present invention, and the vehicle Ve is equipped with an engine (ENG) 1, a first motor (MG1) 2, and a second motor (MG2) 3 as driving power sources.

[0013] The engine 1 can be configured similarly to a conventional gasoline engine or diesel engine, and is configured to generate torque by combusting a mixture of supplied air and fuel.

[0014] Each of the motors 2 and 3 functions as a motor that outputs driving torque when power is applied, similar to a motor used as a driving force source in a conventional electric vehicle or hybrid vehicle. Specifically, each of the motors 2 and 3 is configured as a permanent magnet synchronous motor or induction motor.

[0015] An input shaft 6 of a power split mechanism 5 is connected to an output shaft 4 of the engine 1. The power split mechanism 5 is a differential mechanism configured to split the torque of the input shaft 6 between the first motor 2 and drive wheels 7, and in the example shown in FIG. 1 is configured as a single-pinion planetary gear mechanism. Specifically, the power split mechanism 5 is configured with a sun gear 8, a ring gear 9 arranged concentrically with the sun gear 8, a plurality of pinion gears 10 that mesh with the sun gear 8 and the ring gear 9 and are arranged side by side in the circumferential direction of the input shaft 6, and a carrier 11 that holds each pinion gear 10 so that it can revolve around the rotational center axis of the input shaft 6 and also holds each pinion gear 10 so that it can rotate on its own axis. The input shaft 6 is connected to the carrier 11, and the first motor 2 is connected to the sun gear 8. The carrier 11 corresponds to the "first rotating element" in an embodiment of the present invention, the sun gear 8 corresponds to the "second rotating element" in an embodiment of the present invention, and the ring gear 9 corresponds to the "third rotating element" in an embodiment of the present invention.

[0016] An output gear 13 is formed on the ring gear 9 via a clutch mechanism 12. This clutch mechanism 12 can be configured as a friction clutch mechanism or a meshing clutch mechanism that are conventionally provided in vehicles. In other words, by inputting a signal for engagement or disengagement to a hydraulic actuator or an electromagnetic actuator (not shown), the ring gear 9 and the output gear 13 can be connected to each other so that torque can be transmitted, or the transmission of torque between the ring gear 9 and the output gear 13 can be interrupted.

[0017] The clutch mechanism 12 only needs to be able to selectively interrupt the transmission of torque between the engine 1 or the first motor 2 and the drive wheels 7 via the power split mechanism 5, and therefore the clutch mechanism 12 may be provided between the engine 1 and the carrier 11, or between the first motor 2 and the sun gear 8.

[0018] A driven gear 14 meshes with the output gear 13. This driven gear 14 is attached to one end of a counter shaft 15 arranged parallel to the input shaft 6, and a counter drive gear 16 is attached to the other end of the counter shaft 15. A ring gear 18 of a differential gear unit 17 meshes with the counter drive gear 16, and the left and right drive wheels 7 are connected to the differential gear unit 17. For convenience, only one drive wheel 7 is shown in FIG. 1.

[0019] A drive gear 19 having a smaller diameter than the driven gear 14 is further meshed with the driven gear 14, and the second motor 3 is connected to the drive gear 19. That is, the drive gear 19 is attached to the tip of the output shaft 20 of the second motor 3.

[0020] The first motor 2 and the second motor 3 are connected to a power storage device 22 via a power control unit (PCU) 21 configured with an inverter and a converter (not shown). The power storage device 22 is configured with a capacitor and a battery pack in which secondary batteries are connected in series. By controlling the PCU 21, DC power stored in the power storage device 22 is converted to AC power and supplied to the first motor 2 and the second motor 3. When the first motor 2 and the second motor 3 function as generators, the AC power generated thereby is converted to DC power by the PCU 21 and charged to the power storage device 22. Furthermore, the PCU 21 is configured to be able to supply power generated by the first motor 2 to the second motor 3 without going through the power storage device 22, and similarly, to supply power generated by the second motor 3 to the first motor 2 without going through the power storage device 22.

[0021] In addition, the hybrid vehicle in the embodiment of the present invention is not limited to a vehicle configured to be able to charge the storage device 22 only with the electric power generated by the first motor 2 and the second motor 3, but may also be a so-called plug-in hybrid vehicle that can charge the storage device 22 using an external power source.

[0022] An electronic control unit (hereinafter referred to as ECU) 23 that controls the engine 1, the motors 2 and 3, and the clutch mechanism 12 is provided in the vehicle Ve. Like ECUs provided in conventional vehicles, the ECU 23 is mainly composed of a microcomputer and is configured to determine command signals to be output to the engine 1, the motors 2 and 3, and the clutch mechanism 12 based on input signals and pre-stored maps, arithmetic expressions, etc. That is, command signals are output from the ECU 23 to the spark plugs and fuel injection devices provided in the engine 1, the PCU 21 for controlling the motors 2 and 3, and an actuator that switches the clutch mechanism 12 between an engaged state and a released state. The ECU 23 corresponds to the "controller" in the embodiment of the present invention.

[0023] Signals are input to the ECU 23 from an accelerator opening sensor that detects the depression amount of an accelerator pedal (not shown), a vehicle speed sensor that detects the vehicle speed, a sensor that detects the rotation speed of the first motor 2, a sensor that detects the rotation speed of the second motor 3, a temperature sensor that detects the temperature of the power storage device 22, and an SOC sensor 24 that detects the state of charge (SOC) of the power storage device 22. For convenience, only the SOC sensor 24 is shown in FIG.

[0024] The ECU 23 then selects either the EV driving mode or the HV driving mode based on the SOC detected by the SOC sensor 24, the required driving force corresponding to the amount of depression of the accelerator pedal detected by the accelerator opening sensor, or the vehicle speed detected by the vehicle speed sensor, and outputs command signals to the engine 1, each motor 2, 3, and the clutch mechanism 12.

[0025] Specifically, when the SOC is less than a predetermined mode determination power, the HV driving mode is selected regardless of the required driving force or vehicle speed. Accordingly, the clutch mechanism 12 is engaged, and a torque determined based on the required driving force and the generated power is output from the engine 1. A reaction torque corresponding to the torque output from the engine 1 and the gear ratio of the power split mechanism 5 is output from the first motor 2. When the first motor 2 functions as a generator by outputting the reaction torque from the first motor 2, the power transmitted to the drive wheels 7 becomes smaller than the power required for the vehicle Ve. Therefore, power corresponding to the power shortage is supplied from the first motor 2 or the power storage device 22 to the second motor 3, and the second motor 3 outputs driving torque. The surplus generated power is then charged to the power storage device 22.

[0026] Furthermore, when the SOC is equal to or greater than the mode determination power, the required driving force is small, the vehicle speed is low, and the power required of the vehicle Ve is low, the EV driving mode is selected. Therefore, the clutch mechanism 12 is disengaged, the engine 1 and the first motor 2 are stopped, and torque corresponding to the required driving force is output from the second motor 3. On the other hand, when the required driving force is large or the vehicle speed is high, and the power required of the vehicle Ve is high, the HV driving mode is selected. In other words, the clutch mechanism 12, the engine 1, the first motor 2, and the second motor 3 are controlled in the same way as when the SOC is less than the mode determination power.

[0027] Therefore, the ECU 23 is configured to switch between the EV driving mode and the HV driving mode based on whether the SOC is equal to or greater than the mode determination power, whether the required driving force is equal to or greater than the mode determination driving force, etc. That is, the ECU 23 includes a mode determination unit that determines whether to switch from the EV driving mode to the HV driving mode in accordance with predetermined parameters.

[0028] 2 shows a nomographic diagram illustrating changes in the rotation speeds of the engine 1, first motor 2, and output gear 13 when the SOC is equal to or greater than the mode determination power and the EV driving mode is selected and the vehicle is driven in EV driving mode, and then the SOC drops and the vehicle switches to HV driving mode. In FIG. 2, the "○" symbol indicates the rotation speed of each rotating element that constitutes the power split mechanism 5, and the "●" symbol indicates the rotation speed of the output gear 13.

[0029] 2(a) shows the driving state when the vehicle is running in EV driving mode, with the first motor 2 (sun gear 8) and engine 1 (carrier 11) stopped. Also, because the clutch mechanism 12 is disengaged, the rotation speed of the output gear 13 is set to a rotation speed corresponding to the vehicle speed, while the ring gear 9 is stopped.

[0030] Next, to switch from EV driving mode to HV driving mode, it is necessary to engage the clutch mechanism 12. Therefore, as shown in FIG. 2(b), the rotation speed of the ring gear 9 and the rotation speed of the output gear 13, i.e., the rotation speeds of the drive-side rotating elements and the driven-side rotating elements that constitute the clutch mechanism 12, are synchronized. Specifically, the first motor 2 is rotated in the direction opposite to the rotation direction of the engine 1 during driving. The target rotation speed of the first motor 2 at this time can be calculated based on the rotation speed of the output gear 13, which is determined based on the vehicle speed detected by the vehicle speed sensor, and the gear ratio of the power split mechanism 5. Note that even when the rotation speed of the first motor 2 is controlled as described above, the clutch mechanism 12 is disengaged, and the inertia of the engine 1 and the member (carrier 11) that rotates integrally with the engine 1 is greater than the inertia of the ring gear 9. Therefore, the rotation speed of the ring gear 9 changes while the engine 1 remains stopped. In the following description, synchronizing the rotational speeds of the driving side rotating element and the driven side rotating element that constitute the clutch mechanism 12 will be simply referred to as "synchronizing the clutch mechanism 12."

[0031] As shown in FIG. 2(c), the rotational speed of the first motor 2 is controlled to synchronize the clutch mechanism 12, and then the clutch mechanism 12 is engaged. Next, torque is output from the first motor 2 to motor (crank) the engine 1, thereby starting the engine 1. Specifically, the rotational speed of the first motor 2 is reduced from the rotational speed shown in FIG. 2(c). By outputting torque from the first motor 2 in this way to reduce the rotational speed of the first motor 2, the engine rotational speed increases as shown in FIG. 2(d). That is, the target rotational speed of the first motor 2 at this time can be calculated based on the rotational speed of the output gear 13 (i.e., vehicle speed), the gear ratio of the power split mechanism 5, and the engine target rotational speed for cranking the engine 1. Then, fuel is supplied to the engine 1 and ignition is performed, starting the engine 1, and the vehicle mode is switched to HV driving mode. When motoring the engine 1, torque corresponding to the inertia torque of the engine 1 is transmitted to the output gear 13 in opposition to the driving torque of the vehicle Ve, so the output torque of the second motor 3 is increased to suppress a decrease in driving force.

[0032] As described above, switching from EV driving mode to HV driving mode involves a process of synchronizing the clutch mechanism 12 and a process of motoring the engine 1. Therefore, if the driving mode is switched through the above processes after it is determined that the EV driving mode should be switched to HV driving mode, it takes time to switch to HV driving mode. Furthermore, if the clutch mechanism 12 is engaged in a state where the difference in rotation speed between the driving-side rotating element and the driven-side rotating element (synchronous rotation speed difference) is large in order to shorten this switching time, a sudden change in the rotation speed of the first motor 2 may cause an unintended inertia torque to act on the drive wheels 7, resulting in a shock. Alternatively, if the clutch mechanism 12 is a mesh-type clutch mechanism 12, noise may be generated due to a collision between the meshing surfaces.

[0033] Therefore, the control device for a hybrid vehicle in an embodiment of the present invention is configured to engage the clutch mechanism 12 at an appropriate timing during EV driving mode, and then, when it is determined to switch to HV driving mode, start the engine 1 while the clutch mechanism 12 is engaged. That is, it is configured to be able to determine when the clutch mechanism 12 starts to engage when the SOC is higher than the mode determination power used to determine when to switch to HV driving mode. In other words, the ECU 23 has an engagement determination unit that determines when the clutch mechanism 12 starts to engage depending on the SOC. A flowchart illustrating an example of this control is shown in FIG. 3.

[0034] 3, first, it is determined whether or not the vehicle is in EV mode (step S1). This step S1 can be determined based on whether or not the clutch mechanism 12 is disengaged and the command signal to the second motor 3 is set to a torque value corresponding to the required driving force.

[0035] If the determination in step S1 is negative because the vehicle is not in EV driving mode, the routine is immediately terminated. Conversely, if the determination in step S1 is positive because the vehicle is in EV driving mode, it is determined whether the clutch mechanism 12 is in a released state (step S2). This determination in step S2 can be made based on a signal from the ECU 23 to the actuator that controls the clutch mechanism 12.

[0036] If the determination in step S2 is negative because the clutch mechanism 12 is in an engaged state, the routine is immediately terminated. Conversely, if the determination in step S2 is positive because the clutch mechanism 12 is in a disengaged state, it is determined whether the SOC is less than the engagement determination power used to determine whether the clutch mechanism 12 has started to engage (step S3). This engagement determination power is set to a value greater than the mode determination power used to determine whether to switch from the EV driving mode to the HV driving mode. In other words, even if the SOC is less than the engagement determination power, if the SOC is higher than the mode determination power, a switch to the HV driving mode is not determined. This engagement determination power corresponds to the "first predetermined value" in this embodiment of the present invention, and the mode determination power corresponds to the "second predetermined value" in this embodiment of the present invention. The difference between the engagement determination power and the mode determination power is set so that, for example, the time required for the SOC to decrease from the engagement determination power to the mode determination power is longer than the time required for the clutch mechanism 12 to be fully engaged when maintaining a predetermined operating condition such as the required driving force and vehicle speed at the time the control example shown in Figure 3 is executed, or the maximum driving force at which driving in EV driving mode is possible.

[0037] If the SOC is equal to or greater than the engagement determination power and the result of the negative determination in step S3 is that the SOC of the power storage device 22 is sufficient and the vehicle can continue to travel in the EV driving mode, meaning that there is no need to engage the clutch mechanism 12 to switch to the HV driving mode, and so the routine is immediately terminated. Conversely, if the SOC is less than the engagement determination power and the result of the positive determination in step S3 is that a further decrease in the SOC will result in a decision to switch to the HV driving mode, so engagement control of the clutch mechanism 12 is started before the decision to switch to the HV driving mode is made (step S4).

[0038] Therefore, following step S4, first, the rotation speed of the first motor 2 is controlled to synchronize the clutch mechanism 12 (step S5). Specifically, as shown in FIG. 2(c), the rotation speed of the first motor 2 is controlled so that the differential rotation speed between the ring gear 9 and the output gear 13 is equal to or less than a predetermined difference. The predetermined difference is set so that it is less than the allowable level of abnormal noise when the clutch mechanism 12 is engaged and the allowable magnitude of the inertia torque transmitted to the drive wheels 7 when the clutch mechanism 12 is engaged. Next, the clutch mechanism 12 is engaged (step S6), and this routine is temporarily ended.

[0039] As described above, after the clutch mechanism 12 is engaged, it is determined that the SOC has further decreased beyond the mode determination power, and when the SOC has decreased to below the mode determination power, the engine 1 is started. Conversely, when the SOC increases beyond a predetermined SOC higher than the engagement determination power, for example, when the vehicle Ve travels downhill, the clutch mechanism 12 may be released. In other words, the engagement determination power is set so that a determination to engage the clutch mechanism 12 is made before a determination to switch the driving mode is made.

[0040] As described above, by setting the engagement determination power higher than the mode determination power as the determination threshold for engaging the clutch mechanism 12, engagement of the clutch mechanism 12 can be initiated before the switch to the HV driving mode is established. As a result, time for engaging the clutch mechanism 12 can be secured. Therefore, after the switch to the HV driving mode is determined, it is only necessary to start the engine 1. This shortens the time from when the switch to the HV driving mode is determined to occur until the engine 1 starts and generates driving torque, thereby improving engine start responsiveness. Furthermore, because time for engaging the clutch mechanism 12 can be secured, even when a mesh-type clutch mechanism 12 is employed, the clutch mechanism 12 can be synchronized with relatively high precision. As a result, the generation of inertia torque when the clutch mechanism 12 is engaged and the generation of abnormal noise due to collisions between the meshing surfaces can be suppressed.

[0041] Furthermore, there are provided a mode determination power that determines switching from EV driving mode to HV driving mode, and an engagement determination power that determines the start of engagement of the clutch mechanism 12. Therefore, in order to ensure time to engage the clutch mechanism 12, the SOC that determines switching from EV driving mode to HV driving mode can be set high, thereby preventing early switching to HV driving mode, preventing deterioration in fuel economy, and preventing the driver from feeling strange or uncomfortable when switching to HV driving mode.

[0042] 1, the power split mechanism 5 may be a double-pinion planetary gear mechanism, a Ravigneaux planetary gear mechanism, or a compound planetary gear mechanism that combines multiple planetary gear mechanisms. The second motor 3 is not limited to being connected to the drive wheels 7 to which torque is transmitted from the engine 1 or the first motor 2, but may also be connected to other drive wheels.

[0043] Furthermore, switching from the EV driving mode to the HV driving mode is determined based on various parameters, not just the SOC, such as the required driving force, vehicle speed, and outside temperature. Therefore, the "predetermined parameter" in the embodiment of the present invention may be the required driving force, vehicle speed, outside temperature, etc.

[0044] Specifically, when the required driving force becomes greater than a first predetermined value, it is determined that the clutch mechanism 12 should be engaged, and when the required driving force further exceeds a second predetermined value that is greater than the first predetermined value, it is determined that the EV driving mode should be switched to the HV driving mode, i.e., the engine 1 should be started.

[0045] Alternatively, when the outside air temperature is low, the resistance values ​​of the components constituting the power storage device 22 and PCU 21 become large, making it impossible to pass sufficient current through the second motor 3. Therefore, when the outside air temperature becomes lower than a first predetermined value, it is determined that the clutch mechanism 12 should be engaged, and when the outside air temperature further drops below a second predetermined value that is lower than the first predetermined value, it is determined that the EV driving mode should be switched to the HV driving mode, i.e., the engine 1 should be started. [Explanation of symbols]

[0046] 1 engine 2,3 Motor 5 Power split mechanism 7 drive wheels 8 Sun gear 9,18 Ring gear 11 Carrier 12 Clutch mechanism 13 Output gear 21 Power Control Unit (PCU) 22 Energy storage device 23 Electronic Control Unit (ECU) 24 SOC sensor Vehicle

Claims

1. a power split mechanism for differentially rotating at least three rotation elements, namely, a first rotation element connected to an engine, a second rotation element connected to a first motor, and a third rotation element connected to drive wheels; a second motor connected between the third rotation element and the drive wheels or to other drive wheels different from the drive wheels; and a clutch mechanism for selectively interrupting transmission of torque between the engine and the drive wheels via the power split mechanism, wherein the clutch mechanism is disengaged and torque is transmitted from the second motor to the drive wheels connected to the second motor or to the other drive wheels, and the hybrid vehicle control device is capable of switching between an EV driving mode and an HV driving mode, wherein the clutch mechanism is engaged and torque is transmitted from the engine to the drive wheels, a controller for controlling the clutch mechanism; an engagement determination unit that starts engagement of the clutch mechanism when a predetermined parameter changes beyond a first predetermined value while the EV driving mode is set; a mode determination unit that determines switching from the EV driving mode to the HV driving mode when the predetermined parameter changes to further exceed a second predetermined value that has a predetermined difference from the first predetermined value; Equipped with further comprising a power storage device that supplies power to the second motor; the parameters include a remaining charge of the power storage device, The first predetermined value is set to be higher than the second predetermined value. A control device for a hybrid vehicle.

2. 2. The control device for a hybrid vehicle according to claim 1, The predetermined difference is set so that, when the hybrid vehicle is driven in the EV driving mode under a predetermined driving condition, the time required for the parameter to change from the first predetermined value to the second predetermined value is longer than the time required for the clutch mechanism to be engaged. A control device for a hybrid vehicle.

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