Control device for hybrid vehicle

Abstract

To provide a control device of a hybrid vehicle capable of reducing a load applied to a power interrupting mechanism in switching, and capable of restraining reduction in durability of the power interrupting mechanism.SOLUTION: When switching from a BEV mode in which the engine 12 is stopped and the vehicle travels by driving only the electric motor MG to an HEV mode in which the vehicle travels by driving the engine 12, the engine 12 is started after the power connection / disconnection mechanism 30 is switched to the power transmittable state. As a result, the torque transmitted from the engine 12 side of the power interrupting mechanism 30 becomes small, and the rotation synchronization in the power interrupting mechanism 30 becomes easy, so that the load applied to the power interrupting mechanism 30 at the time of switching is reduced, and the deterioration of the durability of the power interrupting mechanism 30 is suppressed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device for a hybrid vehicle that includes, in order from the engine side, an automatic transmission, a power interrupter, and an electric motor in a power transmission path from the engine to the drive wheels. [Background technology]

[0002] Hybrid vehicles are known that have, in order from the engine side, an automatic transmission, a power interrupter, and an electric motor in a power transmission path from the engine to the drive wheels. One example is the hybrid vehicle described in Patent Document 1. Patent Document 1 discloses that in an electric motor driving mode in which the engine is stopped and the vehicle is driven only by the electric motor, the power interrupter is set to a state in which power is not transmitted, and in a hybrid driving mode in which the vehicle is driven by the engine, the power interrupter is set to a state in which power is transmitted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-36808 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of a hybrid vehicle configured to use a synchronizer mechanism as the power interrupter mechanism, if the engine is started or the automatic transmission is switched to a power transmittable state before the power interrupter mechanism is set to a power transmittable state when switching from the electric motor driving mode to the hybrid driving mode, there is a risk that the power interrupter mechanism may not be able to switch to a power transmittable state, or that problems may occur such as noise associated with the switch and reduced durability of the power interrupter mechanism. This is because, when synchronizing the rotations before and after the power interrupter mechanism, the torque transmitted from the engine side of the power interrupter mechanism becomes large, making it impossible to achieve sufficient rotational synchronization and making the switch impossible, or the load on the power interrupter mechanism becomes large.

[0005] The present invention was made against the background of the above circumstances, and its purpose is to provide a control device for a hybrid vehicle that can reduce the load on the power interrupter mechanism during switching and suppress a decrease in the durability of the power interrupter mechanism. [Means for solving the problem]

[0006] The gist of the first invention is that (a) a control device for a hybrid vehicle includes, in order from the engine side, a hydraulically controlled automatic transmission, a power interrupter mechanism with a synchronizer, and an electric motor in a power transmission path from the engine to the drive wheels, and in an electric motor driving mode in which the engine is stopped and the vehicle is driven only by the electric motor, the automatic transmission is placed in a neutral state and the power interrupter mechanism is set to a state in which it does not transmit power, and (b) when switching from the electric motor driving mode to a hybrid driving mode in which the vehicle is driven by the engine, the power interrupter mechanism is switched to a state in which it can transmit power, and then the engine is started. [Effects of the Invention]

[0007] According to the first aspect of the present invention, when switching from the electric motor driving mode to a hybrid driving mode in which the vehicle is driven by the engine, the control device switches the power interrupter mechanism to a power transmission state and then starts the engine. This reduces the torque transmitted from the engine side of the power interrupter mechanism and makes it easier for the power interrupter mechanism to synchronize its rotation, thereby reducing the load on the power interrupter mechanism during switching and suppressing a decrease in durability of the power interrupter mechanism. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied; [Figure 2] 3 is a flowchart illustrating a main part of the control operation of the electronic control device. [Figure 3] 10 is a flowchart illustrating another embodiment of the control operation of the electronic control device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0010] 1 is a diagram illustrating the schematic configuration of a hybrid vehicle 10 to which the present invention is applied. The hybrid vehicle 10 includes an automatic transmission 20, a power interrupter 30, and an electric motor MG, which are arranged in series in this order from the engine 12 side in a power transmission path from an engine 12 to drive wheels 14.

[0011] The engine 12 is a known internal combustion engine, and an engine torque Te of the engine 12 is controlled by an electronic control device 50, which will be described later.

[0012] The automatic transmission 20 is configured, for example, with a known torque converter or a hydraulically controlled planetary gear type stepped transmission, and is connected to the engine 12 by a crankshaft 16. Power from the crankshaft 16 is output from a countershaft 18 after the gears POSsh of the automatic transmission 20 are switched under the control of a hydraulic control circuit 40 (described later).

[0013] The power interrupting mechanism 30 is provided between the counter shaft 18 connected to the automatic transmission 20 and the motor connecting shaft 22 connected to the electric motor MG, and switches the power transmission state between the automatic transmission 20 and the electric motor MG between a power transmission state and a power non-transmission state. The power interrupting mechanism 30 includes a synchromesh mechanism (hereinafter referred to as a synchro mechanism) S1.

[0014] The synchronizer mechanism S1 is a known synchronization mechanism including a synchronizer ring 32. When the sleeve 34 is operated to the right in the drawing by the hydraulic actuator 42, the synchronizer ring 32 functions to synchronize the rotation of the motor connecting shaft 22 with the countershaft 18, and when the sleeve 34 is moved further to the right in the drawing, meshing teeth formed on the inner peripheral surface of the sleeve 34 mesh with a gear piece 36 that is integrally connected to the motor connecting shaft 22. At this time, the motor connecting shaft 22 is connected to the countershaft 18 via the power interrupter 30 so as not to rotate relative to it, enabling power transmission.

[0015] The electric motor MG is, for example, a so-called motor generator, and is a three-phase synchronous motor. The electric motor MG functions as both an electric motor and a generator, and is connected to a chargeable and dischargeable battery 44 via an inverter 46. The electric motor torque Tmg of the electric motor MG is controlled by an electronic control device 50, which will be described later. The electric motor MG is connected to an output shaft 24, and the torque (power) from the engine 12 and the electric motor MG is transmitted to the drive wheels 14 via the output shaft 24 and a differential gear device 26. The electric motor MG and the differential gear device 26 may be an integrated unit housed in the same case.

[0016] The vehicle 10 further includes a hydraulic control circuit 40 and an electronic control device 50 .

[0017] The hydraulic control circuit 40 is provided to be able to adjust the hydraulic pressure Ptm that controls the shifting of the gear position POSsh of the automatic transmission 20, the hydraulic pressure Ps of the hydraulic actuator 42 of the power interrupter 30, etc. The hydraulic control circuit 40 is provided with a plurality of solenoid valves (not shown), and controls the above-mentioned hydraulic pressures by controlling the control pressures output from the various solenoid valves based on control signals (described later) from the electronic control device 50.

[0018] The electronic control unit 50 functions as a controller that performs various controls of the hybrid vehicle 10, and includes a so-called microcomputer. The electronic control unit 50 corresponds to the "controller" of the present invention.

[0019] The electronic control device 50 is supplied with various signals (e.g., engine rotation speed Ne, motor rotation speed Nmg corresponding to vehicle speed V, accelerator opening θacc as the amount of accelerator operation by the driver, battery remaining charge SOC, etc.) based on detection values ​​from various sensors provided on the vehicle 10 (e.g., engine rotation speed sensor 60, motor rotation speed sensor 62, accelerator opening sensor 64, battery charge amount sensor 66, etc.).

[0020] The electronic control device 50 outputs an engine control signal Se to the engine 12, a shift control signal Stm and a power on / off control signal Ss to the hydraulic control circuit 40 that controls the shifting of the automatic transmission 20 and the power transmission state of the power on / off mechanism 30, and a motor control signal Smg to the inverter 46 that controls the electric motor MG. The shift control signal Stm corresponds to control of the hydraulic oil pressure Ptm, and the power on / off control signal Ss corresponds to control of the hydraulic oil pressure Ps.

[0021] The electronic control unit 50 calculates the amount of driving demand made by the driver to the vehicle 10, such as the required driving torque Trdem at the drive wheels 14, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand map.

[0022] The electronic control device 50 switches between an electric motor driving mode (hereinafter referred to as BEV (Battery Electric Vehicle) mode) in which the engine 12 is stopped and the vehicle is driven only by the electric motor MG, and a hybrid driving mode (hereinafter referred to as HEV (Hybrid Electric Vehicle) mode) in which the vehicle is driven only by the engine 12. Switching between the BEV mode and the HEV mode is suitably performed using a predetermined determination formula based on, for example, the remaining battery charge SOC, the vehicle speed V, and the required driving torque Trdem.

[0023] In the BEV mode, the electronic control device 50 outputs an engine control signal Se to the engine 12 so that the engine 12 is stopped. The electronic control device 50 also outputs a power interrupt control signal Ss to the hydraulic control circuit 40 so that the power interrupter mechanism 30 is in a state where it does not transmit power, and outputs a gear change control signal Stm to the hydraulic control circuit 40 so that the gear stage of the automatic transmission 20 is in a neutral state where it does not transmit power. The electronic control device 50 also outputs a motor control signal Smg to the inverter 46 that controls the electric motor MG so that the vehicle 10 is driven by the required drive torque Trdem.

[0024] In the HEV mode, the electronic control device 50 outputs a power interruption control signal Ss to the hydraulic control circuit 40 so that the power interruption mechanism 30 is in a state where power can be transmitted. Also, the electronic control device 50 calculates the engine torque Te, the gear position POSsh of the automatic transmission 20, and the electric motor torque Tmg using a suitable predetermined method so that the vehicle 10 is driven at the required drive torque Trdem, and outputs an engine control signal Se to the engine 12, a shift control signal Stm to the hydraulic control circuit 40, and a motor control signal Smg to the inverter 46 so that each of these becomes the calculated value.

[0025] Incidentally, when switching from BEV mode to HEV mode while the vehicle 10 is running, if the engine 12 is started or the automatic transmission 20 is switched to a state in which power can be transmitted before the power interrupter mechanism 30 is set to a state in which power can be transmitted, there is a risk that the power interrupter mechanism 30 may not be able to switch to a state in which power can be transmitted, or that problems may occur such as noise associated with the switching and a decrease in durability of the power interrupter mechanism 30. This is because, when synchronizing the rotations before and after the power interrupter mechanism 30, the torque transmitted from the engine side of the power interrupter mechanism 30 becomes large, which prevents sufficient rotation synchronization and makes the switching impossible, or the load on the power interrupter mechanism 30 becomes large.

[0026] Therefore, when switching the driving mode of the vehicle 10 from BEV mode to HEV mode, the electronic control device 50 reduces the load on the power interrupter mechanism 30 at the time of switching by performing the control operation described in the flowchart of Figure 2, thereby suppressing a decrease in the durability of the power interrupter mechanism 30.

[0027] FIG. 2 is a flowchart illustrating the main control operations of the electronic control unit 50 when switching from the BEV mode to the HEV mode, and is executed repeatedly during the BEV mode, for example.

[0028] In FIG. 2, each step in the flowchart corresponds to a function of the electronic control device 50. First, in step (hereinafter, "step" will be omitted) S10, it is determined whether or not there is a request to switch to HEV mode. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, in S20, the power interrupter 30 is switched to a state in which power can be transmitted. After the control operation in S20, in S30, the engine 12 is started, and then in S40, the automatic transmission 20 is switched to a state in which power can be transmitted, i.e., a gear position POSsh for a driving state. Then, in S50, driving in HEV mode is started, thereby completing the switch to HEV mode and terminating this routine.

[0029] As described above, according to the electronic control device 50 of this embodiment, when switching from BEV mode to HEV mode, the power interrupter mechanism 30 is switched to a state in which power can be transmitted, and then the engine 12 is started. As a result, the torque transmitted from the engine 12 side of the power interrupter mechanism 30 becomes small, and rotation synchronization in the power interrupter mechanism 30 becomes easy. Therefore, the load on the power interrupter mechanism 30 at the time of switching is reduced, and a decrease in the durability of the power interrupter mechanism 30 is suppressed. [Example]

[0030] 3 is a flowchart illustrating an example of control operation performed by the electronic control unit 50, which is different from that of the first embodiment, and is executed repeatedly during the BEV mode, for example. In this example, the execution order of the controls of S30 and S40 shown in the flowchart of FIG. 2 of the first embodiment is reversed to S300 and S400.

[0031] As described above, according to this embodiment, the same effects as those of the first embodiment can be obtained.

[0032] The above describes in detail an embodiment of the present invention based on the drawings, but what has been described above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0033] 10: Hybrid vehicle 12: Engine 14: Drive wheels 20: Automatic transmission 30: Power interrupt mechanism 50: Electronic control unit (control unit) MG: Electric motor S1: Synchronization mechanism

Claims

[Claim 1] A control device for a hybrid vehicle, which includes, in order from the engine side, a hydraulically controlled automatic transmission, a power interrupter having a synchronizer, and an electric motor in a power transmission path from an engine to drive wheels, and which runs with the automatic transmission in a neutral state and the power interrupter not transmitting power in an electric motor running mode in which the engine is stopped and the vehicle runs only driven by the electric motor, A control device for a hybrid vehicle, characterized in that when switching from the electric motor driving mode to a hybrid driving mode in which the vehicle is driven by the engine, the power interrupter is switched to a state in which power can be transmitted, and then the engine is started.

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