Control system for hybrid vehicles

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 to an automatic driving mode or 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, if it is in the motor driving mode in the manual driving mode, the acceleration responsiveness may decrease and the drivability may decrease. On the other hand, the hybrid driving mode is a driving mode in which the engine is driven. Therefore, if it is in the hybrid driving mode in the automatic driving mode, the fuel consumption may deteriorate 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 objective can be achieved by a control device for a hybrid vehicle equipped with a motor and an engine, comprising: a switching unit that switches the driving mode of the hybrid vehicle to a motor-driven driving mode in which the engine is stopped and the motor is driven when the required value for the motor is less than a switching value, and switches the driving mode to a hybrid driving 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 the driving mode of the hybrid vehicle is an automatic 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 automatic driving 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 with the vehicle speed.

[0009] The system includes an acquisition unit that acquires the charge level of the battery, which is the power source for the motor, and the second value increases as the charge level of the battery increases. [Effects 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 explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of a hybrid vehicle. [Figure 2] This is a flowchart illustrating the control of setting the switching value. [Figure 3] This is an example diagram of a map that defines the switching values. [Figure 4] This is the first modified example of the map showing the switching values. [Figure 5] This is a flowchart of a modified example of the switching value setting control. [Figure 6] This is a second variation of the map showing the switching values. [Modes for carrying out the invention]

[0012] [Overall configuration of a hybrid vehicle] Figure 1 is a schematic diagram of the hybrid vehicle 1 of 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. In this embodiment, the engine 10 has four cylinders #1 to #4. The number of cylinders in the engine 10 is not limited to four, as long as it has multiple cylinders. The engine 10 is a gasoline engine, but is not limited to this and may be a diesel engine. The engine 10, the first MG 14, and the second MG 15 are the power sources for driving the hybrid vehicle 1.

[0013] The first MG14 and the second MG15 each have the function of a motor that outputs torque when power is supplied, and the function of a generator that generates regenerative power when torque is applied. The first MG14 and the second MG15 are electrically connected to the battery 18 via the PCU 17. The PCU 17 supplies power from the battery 18 to the first MG14 or the second MG15. The PCU 17 also causes the battery 18 to receive regenerative power generated by the first MG14 or the second MG15.

[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 while the engine 10 is stopped. In the motor running mode, the engine 10 stops. Thereby, the fuel efficiency is improved.

[0019] When the required values for the first MG14 and the second MG15 are equal to or greater than 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 and the engine 10 are used in combination, 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 the 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 when 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 to step S1 is No, the ECU100 sets the switching value to value A1 (step S2). If the answer to step S1 is Yes, the ECU100 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 processes performed by the setting unit.

[0023] Figure 3 is an example of a map that defines the switching values. In the map in Figure 3, the vertical axis represents the required value described above, and the horizontal axis represents the vehicle speed. In the example in Figure 3, both values ​​A1 and A2 are fixed values ​​that do not change with vehicle speed. If the driving mode is manual driving mode and the required value is less than value A1, the driving mode is switched to motor driving mode. If the driving mode is manual driving mode and the required value is A1 or greater, the driving mode is switched to hybrid driving mode. If the driving mode is automatic driving mode and the required value is less than value A2, the driving mode is switched to motor driving mode. If the driving mode is automatic driving mode and the required value is A2 or greater, the driving mode is switched to hybrid driving mode.

[0024] Thus, in manual driving mode, the hybrid driving range is larger and the motor-only driving range is smaller than in automatic driving mode. Therefore, the frequency of switching to hybrid driving mode in manual driving mode is ensured. This ensures drivability in manual driving mode. In automatic driving mode, the motor-only driving range is larger and the hybrid driving range is smaller than in manual driving mode. Therefore, the frequency of switching to motor-only driving mode in automatic driving mode is ensured. This improves fuel efficiency in automatic driving mode. In this way, drivability is ensured and fuel efficiency is also improved.

[0025] As mentioned above, value A1 is a fixed value that does not change with vehicle speed. Therefore, drivability is ensured across a wide speed range, regardless of vehicle speed.

[0026] [Differentiation] Figure 4 shows the first modified version of the map showing the switching values. As shown in Figure 4, in the first modified version, value A2 is a variable value according to the vehicle speed. It is specified that value A2 increases as the vehicle speed decreases. Specifically, when the vehicle speed is less than speed V1, value A2 is constant. When the vehicle speed is between speed V1 and speed V2, value A2 increases as the vehicle speed decreases. When the vehicle speed is V2 or higher, value A2 is constant. In this way, a motor-driven range is secured when the vehicle speed is low in the automatic driving mode. Here, the fuel efficiency of engine 10 is worse in the low-speed range than in the high-speed range. Thus, a motor-driven range is secured in the low-speed range where the fuel efficiency of engine 10 is poor. This improves fuel efficiency.

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

[0028] Figure 5 is a flowchart of a modified example of the switching value setting control. In this modified example, the ECU 100 functionally implements an acquisition unit in addition to the switching unit, determination unit, and setting unit described above. If 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 for the first MG 14 and the second MG 15. Step S1a is an example of the processing performed by the acquisition unit.

[0029] Next, the ECU 100 sets the switching value to value A2 (step S3a). Here, it is specified that the value A2 increases as the charge level of the battery 18 increases. Figure 6 is a second modified example of the map showing the switching value. Figure 6 shows the value A2 when the charge level is high and the value A2 when the charge level is low. The value A2 when the charge level is high is greater than the value A2 when the charge level is low. As a result, the motor driving range in automatic driving mode expands as the charge level of the battery 18 increases. Therefore, fuel efficiency improves according to the charge level of the battery 18. Also, the motor driving range in automatic driving mode shrinks as the charge level of the battery 18 decreases. This suppresses over-discharge of the battery 18.

[0030] In the example in Figure 6, value A2 is a variable value that changes according to the vehicle speed, but value A2 may also be a fixed value that does not change with vehicle speed. Value A1 is not limited to a fixed value. The switching value described above may also be calculated using a formula that takes the required value and vehicle speed as arguments.

[0031] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of symbols]

[0032] 1 Hybrid vehicle 10 engines 14. First motor generator 15. Second motor generator 18 batteries 100 ECUs (control unit, 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, A switching unit that, when the required value for the motor is less than a switching value, switches the driving mode of the hybrid vehicle to a motor-driven driving mode in which the engine is stopped and the motor is driven, and when the required value is equal to or greater than the switching value, switches the driving mode to a hybrid driving mode in which the engine is driven, A determination unit that determines whether the driving mode of the hybrid vehicle is automatic driving mode or manual driving mode, The system includes a setting unit that sets the switching value to a first value when the operating mode is the manual operating mode, and sets the switching value to a second value greater than the first value when the operating mode is the automatic operating mode. A control device for a hybrid vehicle, wherein the first value and the second value are variable values ​​corresponding to the vehicle speed of the hybrid vehicle and are greater than zero.

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. A control device for a hybrid vehicle equipped with a motor and an engine, A switching unit that, when the required value for the motor is less than a switching value, switches the driving mode of the hybrid vehicle to a motor-driven driving mode in which the engine is stopped and the motor is driven, and when the required value is equal to or greater than the switching value, switches the driving mode to a hybrid driving mode in which the engine is driven, A determination unit that determines whether the driving mode of the hybrid vehicle is automatic driving mode or manual driving mode, The system includes a setting unit that sets the switching value to a first value when the operating mode is the manual operating mode, and sets the switching value to a second value greater than the first value when the operating mode is the automatic operating mode. As the vehicle speed of the hybrid vehicle decreases, the second value increases. The control device for a hybrid vehicle, wherein the first value is a fixed value that does not change with respect to the vehicle speed.

4. The system includes an acquisition unit that acquires the charge level of the battery, which is the power source for the motor, A control device for a hybrid vehicle according to any one of claims 1 to 3, wherein the second value increases as the charge level of the battery increases.

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