Control device for hybrid vehicle

Abstract

To provide a control device for a hybrid vehicle which ensures drivability and improves fuel efficiency.SOLUTION: The present invention provides a control device for a hybrid vehicle including a motor and an engine, the control device comprising: a switching unit that switches a traveling mode of the hybrid vehicle to a motor traveling mode in which the engine is stopped and the motor is driven when a required value related to the motor is less than a switching value, and switches the traveling mode to a hybrid traveling mode in which the engine is driven when the required value is equal to or greater than the switching value; a determination unit that determines whether a 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.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] There is a hybrid vehicle in which the driving mode can be switched to a motor driving mode or a hybrid driving mode, and the driving mode can be switched between an automatic driving mode and a manual driving mode (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The motor driving mode is a driving mode in which the engine is stopped and the motor is driven. Therefore, when in the manual driving mode and in the motor driving mode, there is a possibility that the acceleration responsiveness decreases and the drivability decreases. On the other hand, the hybrid driving mode is a driving mode in which the engine is driven. Therefore, when in the automatic driving mode and in the hybrid driving mode, there is a possibility that the fuel consumption deteriorates due to the driving of the engine.

[0005] Therefore, an object of the present invention is to provide a control device for a hybrid vehicle that ensures drivability and improves fuel consumption.

Means for Solving the Problems

[0006] The above object can be achieved by a control device for a hybrid vehicle including a motor and an engine, the control device including: a switching unit configured to switch a driving mode of the hybrid vehicle to a motor driving mode in which the engine is stopped and the motor is driven when a required value related to the motor is less than a switching value, and to switch the driving mode to a hybrid driving mode in which the engine is driven when the required value is greater than or equal to the switching value; a determination unit configured to determine whether an operation mode of the hybrid vehicle is an automatic operation mode or a manual operation mode; and a setting unit configured to set the switching value to a first value when the operation mode is the manual operation mode, and to set the switching value to a second value greater than the first value when the operation mode is the automatic operation mode.

[0007] The second value may increase as the vehicle speed of the hybrid vehicle decreases.

[0008] The first value may be a fixed value that does not change depending on the vehicle speed.

[0009] The control device may include an acquisition unit configured to acquire a state of charge of a battery that is a power source of the motor, and the second value may increase as the state of charge of the battery increases.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a control device for a hybrid vehicle that ensures drivability and improves fuel efficiency.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0012] [Schematic Configuration of Hybrid Vehicle] FIG. 1 is a schematic configuration diagram of a hybrid vehicle 1 according to this embodiment. The hybrid vehicle 1 includes an ECU (Electronic Control Unit) 100, an engine 10, a first motor generator (hereinafter referred to as "first MG (Motor Generator)") 14, a second motor generator (hereinafter referred to as "second MG") 15, a PCU (Power Control Unit) 17, a battery 18, a power split mechanism 50, a transmission mechanism 51, a transmission 52, a drive shaft 53, a differential 54, and drive wheels 55. The engine 10 has four cylinders #1 to #4 in this embodiment. The number of cylinders is not limited to four as long as the engine 10 has a plurality of cylinders. The engine 10 is a gasoline engine, but is not limited thereto and may 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.

[0013] Each of the first MG 14 and the second MG 15 has a function as a motor that outputs torque by power supply and a function as a generator that generates regenerative power when torque is applied. 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 in the first MG 14 or the second MG 15.

[0014] The power split 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 split mechanism 50. The output shaft of the power split 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.

[0015] 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.

[0016] The ECU 100 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to the running control of the vehicle, 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 realizes a switching unit, a determination unit, and a setting unit, which will be described later.

[0017] An ignition switch 71, an accelerator opening sensor 72, a vehicle speed sensor 73, and a 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. 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.

[0018] When the required values regarding the first MG 14 and the second MG 15 are less than a predetermined switching value, the ECU 100 switches the running mode of the hybrid vehicle 1 to the motor running mode. The motor running mode is a running mode in which at least one of the first MG 14 and the second MG 15 is used as a power source with the engine 10 stopped. In the motor running mode, the engine 10 stops. Thereby, the fuel consumption is improved.

[0019] When the required values for the first MG14 and the second MG15 are greater than or equal to the switching value, the ECU100 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 used as a power source. Even when at least one of the first MG14 and the second MG15 is used in combination with the engine 10, it is included in the hybrid driving mode. In the hybrid driving mode, the engine 10 is driven. Therefore, the acceleration responsiveness is improved and drivability is ensured. Incidentally, the required values for the first MG14 and the second MG15 are calculated by the ECU100 based on the accelerator opening degree, the driving state, and the like. The required values for the first MG14 and the second MG15 are, for example, the output values required for the first MG14 and the second MG15, and the torque values required for the first MG14 and the second MG15. The switching of the driving mode is an example of the process executed by the switching unit.

[0020] The ECU100 switches the driving mode of the hybrid vehicle 1 to the automatic driving mode or the manual driving mode. The automatic driving mode is a driving mode in which the hybrid vehicle 1 autonomously drives in automatic driving. The manual driving mode is a driving mode in which the vehicle travels according to the driver's manual operation. In the manual driving mode, the driver performs operations of steering, accelerating, and decelerating. The switching of the driving mode may be performed by the ECU100 in response to the driver's operation, or may be automatically performed by the ECU100.

[0021] [Switching Value Setting Control] FIG. 2 is a flowchart illustrating the switching value setting control. This control is repeatedly executed at a predetermined cycle while the ignition is on. The ECU100 determines whether the driving mode is the automatic 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.

[0022] If the answer is "No" in step S1, the ECU 100 sets the switching value to value A1 (step S2). If the answer is "Yes" in step S1, the ECU 100 sets the switching value to value A2 (step S3). Value A2 is a value larger than value A1. Steps S2 and S3 are examples of processes executed by the setting unit.

[0023] Figure 3 is an exemplary diagram of a map defining the switching value. In the map of Figure 3, the vertical axis is the above-described required value and the horizontal axis indicates the vehicle speed. In the example of Figure 3, both value A1 and A2 are fixed values that do not change depending on the vehicle speed. When the driving mode is the manual driving mode and the required value is less than value A1, the driving mode is switched to the motor driving mode. When the driving mode is the manual driving mode and the required value is greater than or equal to value A1, the driving mode is switched to the hybrid driving mode. When the driving mode is the automatic driving mode and the required value is less than value A2, the driving mode is switched to the motor driving mode. When the driving mode is the automatic driving mode and the required value is greater than or equal to value A2, the driving mode is switched to the hybrid driving mode.

[0024] As described above, in the case of the manual driving mode, the hybrid driving area is larger and the motor driving area is smaller than in the case of the automatic driving mode. Therefore, the frequency of switching to the hybrid driving mode in the manual driving mode is ensured. For this reason, drivability in the manual driving mode is ensured. In the case of the automatic driving mode, the motor driving area is larger and the hybrid driving area is smaller than in the case of the manual driving mode. Therefore, the frequency of switching to the motor driving mode in the automatic driving mode is ensured. For this reason, the fuel efficiency in the automatic driving mode is improved. In this way, drivability is ensured and the fuel efficiency is also improved.

[0025] As described above, value A1 is a fixed value that does not change depending on the vehicle speed. For this reason, drivability is ensured in a wide speed range regardless of the vehicle speed.

[0026] [Modification Example] FIG. 4 is a first modified example of a map showing switching values. As shown in FIG. 4, in the first modified example, the value A2 is a variable value according to the vehicle speed. It is defined such that the value A2 increases as the vehicle speed decreases. Specifically, when the vehicle speed is less than the speed V1, the value A2 is constant. When the vehicle speed is equal to or greater than the speed V1 and less than the speed V2, the value A2 increases as the vehicle speed decreases. When the vehicle speed is equal to or greater than the speed V2, the value A2 is constant. In this way, the motor driving range is ensured when the vehicle speed is low in the automatic driving mode. Here, the fuel consumption of the engine 10 is worse in the low speed range than in the high speed range. In such a low speed range where the fuel consumption of the engine 10 is poor, the motor driving range is ensured. This improves the fuel consumption.

[0027] When the vehicle speed is less than the speed V1 and when the vehicle speed is equal to or greater than the speed V2, the value A2 is not limited to being constant. The value A2 may increase stepwise or continuously as the vehicle speed decreases. When the vehicle speed is equal to or greater than the speed V2, the value A2 is not limited to being the same as the value A1. When the vehicle speed is equal to or greater than the speed V2, the value A2 may be greater than the value A1.

[0028] FIG. 5 is a flowchart of a modified example of switching value setting control. In this modified example, in addition to the switching unit, determination unit, and setting unit described above, the ECU 100 functionally realizes an acquisition unit. If Yes in step S1, 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 for the first MG 14 and the second MG 15. Step S1a is an example of the process executed by the acquisition unit.

[0029] Next, the ECU 100 sets the switching value to value A2 (step S3a). Here, it is defined that the larger the charge amount of the battery 18, the larger the value A2. FIG. 6 is a second modification of the map showing the switching value. In FIG. 6, the value A2 when the charge amount is large and the value A2 when the charge amount is small are shown. The value A2 when the charge amount is large is larger than the value A2 when the charge amount is small. Thereby, the larger the charge amount of the battery 18, the larger the motor driving region in the automatic driving mode. Therefore, the fuel efficiency is improved according to the charge amount of the battery 18. Also, the smaller the charge amount of the battery 18, the smaller the motor driving region in the automatic driving mode. Thereby, over-discharge of the battery 18 is suppressed.

[0030] In the example of FIG. 6, the value A2 is a variable value that changes according to the vehicle speed, but the value A2 may be a fixed value that does not change according to the vehicle speed. The value A1 is not limited to a fixed value. The above-described switching value may be calculated by an arithmetic expression using the required value and the vehicle speed as arguments.

[0031] As described above in detail with respect to the embodiments of the present invention, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0032] 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)

Claims

1. A control device for a hybrid vehicle equipped with a motor and an engine, comprising: a switching unit configured to switch the driving mode of the hybrid vehicle to a motor driving mode in which the engine is stopped and the motor is driven when a required value related to the motor is less than a switching value, and to switch the driving mode to a hybrid driving mode in which the engine is driven when the required value is greater than or equal to the switching value; a determination unit configured to determine whether the driving mode of the hybrid vehicle is an automatic driving mode or a manual driving mode; 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 automatic driving mode. A control device for a hybrid vehicle comprising the above components.

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

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

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

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