Control device for hybrid vehicle

Abstract

The invention relates to a control device for a hybrid vehicle. The present invention addresses the problem of providing a control device for a hybrid vehicle that ensures drivability and improves fuel efficiency. A control device for a hybrid vehicle provided with a motor and an engine, when a request value related to the motor is lower than a switching value, the driving mode of the hybrid vehicle is switched to a motor driving mode in which the engine is stopped and the motor is driven. And a switching unit that switches the travel mode to a hybrid travel mode in which the engine is driven when the request value is equal to or greater than the switching value. A determination unit that determines whether the driving mode of the hybrid vehicle is an automatic driving mode or a manual driving mode; and a control unit that sets the switching value to a first value when the driving mode is the manual driving mode. And a setting unit that sets the switching value to a second value that is greater than the first value when the driving mode is the automatic driving mode.

Description

Technical Field

[0001] The present invention relates to a control device for a hybrid vehicle. Background Art

[0002] There is a hybrid vehicle that can switch the driving mode to a motor driving mode or a hybrid driving mode, and switch the driving mode to an autonomous driving mode or a manual driving mode (for example, refer to Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-034736 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The motor driving mode is a driving mode in which the engine stops and the motor drives. Therefore, in the manual driving mode, if it is the motor driving mode, there is a risk that the acceleration responsiveness decreases and the driving performance deteriorates. On the other hand, the hybrid driving mode is a driving mode in which the engine drives. Therefore, in the autonomous driving mode, if it is the hybrid driving mode, there is a risk that the fuel efficiency deteriorates due to the driving of the engine.

[0008] Therefore, an object of the present invention is to provide a control device for a hybrid vehicle that ensures driving performance and improves fuel efficiency.

[0009] Technical Solution for Solving the Problems

[0010] The above object can be achieved by a control device for a hybrid vehicle, the hybrid vehicle including a motor and an engine, wherein the control device for the hybrid vehicle includes a switching unit that switches the driving mode of the hybrid vehicle to a motor driving mode in which the engine stops and the motor drives when a request value related to the motor is lower than a switching value, and switches the driving mode to a hybrid driving mode in which the engine drives when the request value is equal to or higher than the switching value; a determination unit that determines whether the driving mode of the hybrid vehicle is an autonomous driving mode or a manual driving mode; and a setting unit that sets the switching value to a first value when the driving mode is the manual driving mode, and sets the switching value to a second value greater than the first value when the driving mode is the autonomous driving mode.

[0011] It is also possible that the lower the vehicle speed of the hybrid vehicle, the greater the second value.

[0012] The first value may also be a fixed value that does not change according to the vehicle speed.

[0013] There is an acquisition unit that acquires the charge amount of a battery that is a power source for the motor. The larger the charge amount of the battery, the larger the second value becomes.

[0014] Advantages of the Invention

[0015] According to the present invention, it is possible to provide a control device for a hybrid vehicle that ensures driving performance and improves fuel efficiency. Description of the Drawings

[0016] Figure 1 is a schematic configuration diagram of a hybrid vehicle.

[0017] Figure 2 is a flowchart illustrating switching value setting control.

[0018] Figure 3 is an example diagram of a graph defining a switching value.

[0019] Figure 4 is a first modification example of a graph showing a switching value.

[0020] Figure 5 is a flowchart of a modification example of switching value setting control.

[0021] Figure 6 is a second modification example of a graph showing a switching value.

[0022] (Reference Signs)

[0023] 1: Hybrid vehicle; 10: Engine; 14: First motor generator; 15: Second motor generator; 18: Battery; 100: ECU (control device, switching unit, determination unit, setting unit, acquisition unit); A1: Value (first value); A2: Value (second value). Detailed Description of the Invention

[0024] [Schematic Configuration of Hybrid Vehicle]

[0025] Figure 1This is a schematic structural diagram of a hybrid vehicle 1 according to this embodiment. The hybrid vehicle 1 includes an ECU (Electronic Control Unit), an engine 10, a first motor generator (hereinafter referred to as "the first MG (Motor Generator)") 14, a second motor generator (hereinafter referred to as "the second MG") 15, a PCU (Power Control Unit) 17, a battery 18, a power distribution mechanism 50, a transmission mechanism 51, a transmission 52, a drive shaft 53, a differential 54, and drive wheels 55. In this embodiment, the engine 10 has four cylinders #1 to #4. As long as the engine 10 has a plurality of cylinders, the number of cylinders is not limited to four. The engine 10 is a gasoline engine, but is not limited thereto, and may also be a diesel engine. The engine 10, the first MG 14, and the second MG 15 are power sources for driving the hybrid vehicle 1.

[0026] The first MG 14 and the second MG 15 each have a function as a motor that outputs torque by power supply and a function as a generator that generates regenerative power by being given torque. The first MG 14 and the second MG 15 are electrically connected to the battery 18 via the PCU 17. The PCU 17 supplies power from the battery 18 to the first MG 14 or the second MG 15. The PCU 17 causes the battery 18 to receive the regenerative power generated by power generation in the first MG 14 or the second MG 15.

[0027] The power distribution mechanism 50 mechanically connects the crankshaft of the engine 10, the rotating shaft of the first MG 14, and the output shaft of the power distribution mechanism 50. The output shaft of the power distribution mechanism 50 is connected to the transmission mechanism 51. The rotating shaft of the second MG 15 is connected to the transmission mechanism 51. The transmission mechanism 51 is connected to the transmission 52. The transmission 52 is connected to the drive shaft 53. The driving forces of the engine 10, the first MG 14, and the second MG 15 are transmitted to the drive wheels 55 via the transmission mechanism 51, the transmission 52, the drive shaft 53, and the differential 54.

[0028] The transmission 52 is a stepped automatic transmission provided between the second MG 15 and the drive shaft 53. The transmission 52 changes the gear ratio under the control of the ECU 100.

[0029] The ECU 100 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to vehicle driving control and a memory that stores control programs and data. The ECU 100 is an example of a control device for a hybrid vehicle. The ECU 100 functionally implements a switching unit, a determination unit, and a setting unit described later.

[0030] The ignition switch 71, accelerator opening sensor 72, vehicle speed sensor 73, and SOC (State Of Charge) sensor 74 are electrically connected to the ECU 100. The ignition switch 71 detects the on / off state of the ignition device. The accelerator opening sensor 72 detects the operation position of the accelerator pedal. The vehicle speed sensor 73 detects the vehicle speed of the hybrid vehicle 1. The SOC sensor 74 detects the charge amount of the battery 18.

[0031] When the request values related to the first MG 14 and the second MG 15 are lower than a predetermined switching value, the ECU 100 switches the driving mode of the hybrid vehicle 1 to the motor driving mode. The motor driving mode is a driving mode in which at least one of the first MG 14 and the second MG 15 is set as the power source while the engine 10 is stopped. In the motor driving mode, the engine 10 stops. Thereby, the fuel efficiency is improved.

[0032] When the request values related to the first MG 14 and the second MG 15 are equal to or higher than the switching value, the ECU 100 switches the driving mode to the hybrid driving mode. The hybrid driving mode is a driving mode in which the engine 10 is driven and the engine 10 is set as the power source. The case where at least one of the first MG 14 and the second MG 15 and the engine 10 are used is also included in the hybrid driving mode. In the hybrid driving mode, the engine 10 is driven. Therefore, the acceleration responsiveness is improved and the driving performance is ensured. In addition, the request values related to the first MG 14 and the second MG 15 are calculated by the ECU 100 based on the accelerator opening, driving state, etc. The request values related to the first MG 14 and the second MG 15 refer to, for example, the requested output values of the first MG 14 and the second MG 15, and the requested torque values of the first MG 14 and the second MG 15. The switching of the driving mode is an example of the process executed by the switching unit.

[0033] The ECU 100 switches the driving mode of the hybrid vehicle 1 to the autonomous driving mode or the manual driving mode. The autonomous driving mode is a driving mode in which the hybrid vehicle 1 autonomously travels through autonomous driving. The manual driving mode is a driving mode in which the vehicle travels according to the driver's manual operations. In the manual driving mode, the driver performs operations of steering, accelerating, and decelerating. The switching of the driving mode can be performed, for example, by the ECU 100 accepting the driver's operation, or the ECU 100 can perform the switching automatically.

[0034] [Switching value setting control]

[0035] Figure 2It is a flowchart illustrating the switching value setting control. This control is repeatedly executed at a predetermined cycle in the state where the ignition device is turned on. The ECU 100 determines whether the driving mode is the autonomous driving mode (step S1). When the driving mode is the manual driving mode, it is determined as "No" in step S1. Step S1 is an example of the process executed by the determination unit.

[0036] When it is "No" in step S1, the ECU 100 sets the switching value to value A1 (step S2). When it is "Yes" in step S1, the ECU 100 sets the switching value to value A2 (step S3). Value A2 is a value greater than value A1. Steps S2 and S3 are examples of the processes executed by the setting unit.

[0037] Figure 3 It is an example diagram of the figure that defines the switching value. In Figure 3 the figure, the vertical axis is the above-mentioned requested value, and the horizontal axis represents the vehicle speed. In Figure 3 the example, both value A1 and A2 are fixed values that do not change according to the vehicle speed. When the driving mode is the manual driving mode and the requested value is lower than value A1, the driving mode is switched to the motor driving mode. When the driving mode is the manual driving mode and the requested value is equal to or higher than value A1, the driving mode is switched to the hybrid driving mode. When the driving mode is the autonomous driving mode and the requested value is lower than value A2, the driving mode is switched to the motor driving mode. When the driving mode is the autonomous driving mode and the requested value is equal to or higher than value A2, the driving mode is switched to the hybrid driving mode.

[0038] In this way, in the case of the manual driving mode, compared with the case of the autonomous driving mode, the hybrid driving area is larger and the motor driving area is smaller. Therefore, the frequency of switching to the hybrid driving mode in the manual driving mode is ensured. Therefore, the driving performance in the manual driving mode is ensured. In the case of the autonomous driving mode, compared with the case of the manual driving mode, the motor driving area is larger and the hybrid driving area is smaller. Therefore, the frequency of switching to the motor driving mode in the autonomous driving mode is ensured. Therefore, the fuel efficiency in the autonomous driving mode is improved. In this way, the driving performance is ensured and the fuel efficiency is also improved.

[0039] As described above, value A1 is a fixed value that does not change according to the vehicle speed. Therefore, regardless of the vehicle speed, the driving performance is ensured in a wide speed range.

[0040] [Variant Example]

[0041] Figure 4 It is the first variant example of the figure showing the switching value. As Figure 4As shown, in the first modification example, the value A2 is a variable value corresponding to the vehicle speed. It is stipulated that the lower the vehicle speed, the greater the value A2. Specifically, when the vehicle speed is lower than the speed V1, the value A2 is constant. When the vehicle speed is equal to or higher than the speed V1 and lower than the speed V2, the lower the vehicle speed, the greater the value A2. When the vehicle speed is equal to or higher than the speed V2, the value A2 is constant. This ensures the motor driving area when the vehicle speed is low in the autonomous driving mode. Here, compared with the high-speed area, the fuel efficiency of the engine 10 is poor in the low-speed area. Thus, in the low-speed area where the fuel efficiency of the engine 10 is poor, the motor driving area is ensured. As a result, the fuel efficiency is improved.

[0042] When the vehicle speed is lower than the speed V1 and when the vehicle speed is equal to or higher than the speed V2, the value A2 is not limited to being constant. As long as the lower the vehicle speed, the greater the value A2 increases stepwise or continuously. It is not limited that when the vehicle speed is equal to or higher than the speed V2, the value A2 is the same as the value A1. It is also possible that when the vehicle speed is equal to or higher than the speed V2, the value A2 is greater than the value A1.

[0043] Figure 5 It is a flowchart of a modification example of the switching value setting control. In this modification example, in addition to the above-mentioned switching unit, determination unit, and setting unit, the ECU 100 also functionally implements an acquisition unit. When the answer in step S1 is "Yes", the ECU 100 acquires the charge amount of the battery 18 based on the detection value of the SOC sensor 74 (step S1a). The battery 18 is the power source of the first MG 14 and the second MG 15. Step S1a is an example of the process executed by the acquisition unit.

[0044] Next, the ECU 100 sets the switching value to the value A2 (step S3a). Here, it is stipulated that the greater the charge amount of the battery 18, the greater the value A2. Figure 6 It is the second modification example of the diagram showing the switching value. In Figure 6 it shows the value A2 in the case of a large charge amount and the value A2 in the case of a small charge amount. The value A2 in the case of a large charge amount is greater than the value A2 in the case of a small charge amount. Thus, the greater the charge amount of the battery 18, the more the motor driving area in the autonomous driving mode expands. Therefore, the fuel efficiency is improved according to the charge amount of the battery 18. In addition, the smaller the charge amount of the battery 18, the smaller the motor driving area in the autonomous driving mode. Thus, over-discharge of the battery 18 is suppressed.

[0045] In Figure 6 the example, the value A2 is a variable value that changes corresponding to the vehicle speed, but the value A2 can also be a fixed value that does not change according to the vehicle speed. The value A1 is not limited to a fixed value. It is also possible to calculate the above-mentioned switching value through an arithmetic expression with the requested value and the vehicle speed as independent variables.

[0046] As mentioned above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

Claims

1. A control device for a hybrid vehicle, the hybrid vehicle including a motor and an engine, the control device for the hybrid vehicle comprising: a switching unit configured to switch a driving mode of the hybrid vehicle to a motor driving mode in which the engine stops and the motor drives when a request value related to the motor is lower than a switching value, and to switch the driving mode to a hybrid driving mode in which the engine drives when the request value is equal to or higher than the switching value; a determination unit configured to determine whether the driving mode of the hybrid vehicle is an autonomous driving mode or a manual driving mode; and a setting unit configured to set the switching value to a first value when the driving mode is the manual driving mode, and to set the switching value to a second value greater than the first value when the driving mode is the autonomous driving mode.

2. The control device for a hybrid vehicle according to claim 1, wherein the lower the vehicle speed of the hybrid vehicle, the greater the second value.

3. The control device for a hybrid vehicle according to claim 2, wherein the first value is a fixed value that does not change according to the vehicle speed.

4. The control device for a hybrid vehicle according to any one of claims 1 to 3, wherein the control device for the hybrid vehicle includes an acquisition unit configured to acquire a charge amount of a battery that is a power source for the motor, the greater the charge amount of the battery, the greater the second value.

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