Vehicle control device

Abstract

The present application provides a vehicle control device capable of appropriately continuing an expansion mode. The control device sets an EV expansion mode that increases a travel frequency in an EV travel mode, based on a request from a user. When set to the EV expansion mode, if a required driving force of the vehicle is less than an EV cancel output threshold and a remaining capacity of a battery is equal to or more than a lower limit threshold of the EV expansion mode, the vehicle is caused to travel in the EV travel mode. Further, when set to the EV expansion mode and the vehicle is caused to travel in the EV travel mode, if the required driving force becomes equal to or more than the EV cancel output threshold, the engine is caused to operate and switched to a travel mode other than the EV travel mode. Moreover, if the remaining capacity of the battery when the required driving force is equal to or more than the EV cancel output threshold is equal to or more than a holding lower limit threshold that is greater than the lower limit threshold of the EV expansion mode, the EV expansion mode is continued, and if less than the holding lower limit threshold, the EV expansion mode is canceled.

Description

Technical Field

[0001] This invention relates to a vehicle control device for controlling a vehicle. Background Technology

[0002] In recent years, research aimed at achieving a low-carbon or decarbonized society as a concrete countermeasure to address global climate change has been very active. In the vehicle sector, there is also a strong demand to reduce CO2 emissions, and the electrification of power sources is developing rapidly. Specifically, the development of vehicles such as electric vehicles (EVs) or hybrid electric vehicles (HEVs), which consist of an electric motor as the power source and a battery as the power supply to that motor (hereinafter also referred to as "electric vehicles"), is underway.

[0003] Patent Document 1 discloses the following technology: In a vehicle that can switch between EV mode, which is driven by only the motor, and HEV mode, which is driven by the motor and engine, when driving in HEV mode, if the accelerator opening stays in the lag region between the engine start line and the engine stop line for more than a preset transition time, EV time transition processing to EV mode is performed, thereby increasing the driving frequency in EV mode.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-221853 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] There exists a vehicle comprising an internal combustion engine, an electric storage device, an electric motor driven at least by a power supply from the electric storage device, and drive wheels driven by at least one of the internal combustion engine and the electric motor. This vehicle is capable of operating in a first driving mode, in which the internal combustion engine is stopped and the electric motor drives the drive wheels based on a power supply from the electric storage device. Furthermore, in such a vehicle, there exists an extended mode that can be set to increase the driving frequency in the first driving mode according to the user's request. However, in the prior art, from the viewpoint of appropriately continuing this extended mode, there is room for improvement.

[0009] The present invention provides a vehicle control device that can appropriately expand the modes in order to improve the commercial viability of the vehicle.

[0010] Solution for solving the problem

[0011] This invention provides a vehicle control device for controlling a vehicle, the vehicle comprising an internal combustion engine, an electric storage device, an electric motor driven at least according to a power supply from the electric storage device, and drive wheels driven by at least one of the internal combustion engine and the electric motor.

[0012] in,

[0013] The vehicle has a first driving mode and a second driving mode. In the first driving mode, the vehicle moves by stopping the internal combustion engine and driving the drive wheels with power supplied from the energy storage device. In the second driving mode, the internal combustion engine is activated for driving.

[0014] The vehicle control device is configured to set an extended mode that increases the driving frequency in the first driving mode according to requests from the user of the vehicle.

[0015] When the vehicle control device is set to the extended mode, if the required driving force for the vehicle's operation is less than a specified value and the remaining capacity of the energy storage device is above the specified extended mode lower limit threshold, the vehicle will operate in the first driving mode.

[0016] When the vehicle control device is set to the expanded mode and the vehicle is driven in the first driving mode, if the required driving force is above the predetermined value, it activates the internal combustion engine to drive the vehicle in the second driving mode, and...

[0017] If the remaining capacity is above a predetermined minimum threshold when the required driving force is above the specified value, the vehicle control device continues the expansion mode; conversely, if the remaining capacity is below the minimum threshold, the vehicle control device deactivates the expansion mode.

[0018] The lower limit threshold is maintained at a value greater than the upper limit threshold of the expansion mode.

[0019] Invention Effects

[0020] According to the present invention, a vehicle control device is provided that can appropriately continue to expand the model and seek to improve the commerciality of the vehicle. Attached Figure Description

[0021] Figure 1 This is a diagram showing the schematic structure of the vehicle 10 according to this embodiment.

[0022] Figure 2 This diagram illustrates an example of a control device 20 controlling vehicle 10 continuing in EV extended mode.

[0023] Figure 3 This diagram illustrates an example of a situation where the control device 20 controlling the vehicle 10 does not continue in EV extended mode.

[0024] Figure 4 This diagram illustrates an example of a situation where the engine starts frequently.

[0025] Figure 5 This is a diagram illustrating examples of changes to the lower limit threshold based on vehicle speed and road gradient.

[0026] Figure 6 This is a diagram illustrating a change in the lower limit threshold based on a predetermined driving path.

[0027] Figure 7 This is an example of how the remaining capacity information is displayed when the EV expansion mode is deactivated because the remaining capacity of the battery BAT is less than the lower limit threshold of the EV expansion mode.

[0028] Figure 8 This is an example of how the remaining capacity information is displayed when the EV extended mode is deactivated because the required driving force is above the EV release output threshold and the remaining capacity of the battery BAT is less than the maintenance lower limit threshold.

[0029] Explanation of reference numerals in the attached figures:

[0030] 10 vehicles

[0031] 14 Display devices

[0032] 20. Control device (vehicle control device)

[0033] BAT (Battery, Energy Storage Device)

[0034] DW drive wheel

[0035] ENG (Internal Combustion Engine)

[0036] MG1 First Electric Generator (Motor)

[0037] MG2 Second Electric Generator (Generator). Detailed Implementation

[0038] Hereinafter, an embodiment of the vehicle control device of the present invention will be described in detail with reference to the accompanying drawings.

[0039] [vehicle]

[0040] First, an embodiment of the vehicle control device of the present invention, namely a vehicle equipped with the control device, will be described. For example... Figure 1As shown, the vehicle 10 in this embodiment is a hybrid electric vehicle, configured to include an engine ENG (e.g., an internal combustion engine), a first electric generator MG1 (e.g., an electric motor), a second electric generator MG2 (e.g., a generator), a battery BAT (e.g., an energy storage device), a clutch CL, a power conversion device 11, various sensors 12, a navigation device 13, a display device 14, and a control device 20 (e.g., a vehicle control device). Furthermore, in... Figure 1 In the diagram, thick solid lines represent mechanical connections, double dashed lines represent electrical wiring, and thin solid arrows represent the transmission and reception of control or detection signals.

[0041] The engine ENG is, for example, a gasoline engine or a diesel engine, and outputs power generated by burning the supplied fuel. The engine ENG is connected to a second electric generator MG2 and, via a clutch CL, to the drive wheels DW of the vehicle 10. The power output by the engine ENG (hereinafter also referred to as "engine ENG output") is transmitted to the second electric generator MG2 when the clutch CL is disengaged, and to both the second electric generator MG2 and the drive wheels DW when the clutch CL is engaged. Further details regarding the second electric generator MG2 and the clutch CL will be provided later.

[0042] The first electric generator MG1 is an electric generator (so-called a traction motor) that primarily serves as the drive source for the vehicle 10, and is, for example, composed of an AC motor. The first electric generator MG1 is electrically connected to the battery BAT and the second electric generator MG2 via a power conversion device 11. Power from at least one of the battery BAT and the second electric generator MG2 can be supplied to the first electric generator MG1. The first electric generator MG1 operates as an electric motor by being supplied with power, outputting power to propel the vehicle 10. Furthermore, the first electric generator MG1 is connected to the drive wheel DW, and the power output by the first electric generator MG1 (hereinafter also referred to as "the output of the first electric generator MG1") is transmitted to the drive wheel DW. By transmitting at least one of the output of the engine ENG and the output of the first electric generator MG1 to the drive wheel DW, the vehicle 10 is propelled.

[0043] Furthermore, the first electric generator MG1 performs regenerative operation as a generator when the vehicle 10 brakes (when it rotates via the engine ENG or drive wheel DW), generating electricity (so-called regenerative power generation). The electricity generated by the regenerative operation of the first electric generator MG1 (hereinafter also referred to as "regenerative power") is supplied to the battery BAT, for example, via the power conversion device 11. Thus, the battery BAT can be charged by regenerative power.

[0044] Alternatively, the regenerated electricity can be supplied to the second electric generator MG2 via the power conversion device 11 instead of being supplied to the battery BAT. By supplying the regenerated electricity to the second electric generator MG2, "waste power" can be generated without charging the battery BAT. Furthermore, during waste power generation, the regenerated electricity supplied to the second electric generator MG2 is used to drive the second electric generator MG2, and the resulting power is input to the engine ENG, where it is consumed by mechanical friction and other losses.

[0045] The second electric generator MG2 is an electric generator primarily used as a generator, and is, for example, composed of an AC motor. The second electric generator MG2 is driven by the power of the engine ENG to generate electricity. The electricity generated by the second electric generator MG2 is supplied via a power conversion device 11 to at least one of the battery BAT and the first electric generator MG1. By supplying the electricity generated by the second electric generator MG2 to the battery BAT, the battery BAT can be charged. Furthermore, by supplying the electricity generated by the second electric generator MG2 to the first electric generator MG1, the first electric generator MG1 can be driven.

[0046] The power conversion device 11 is a device that converts input power and outputs converted power (a so-called power control unit, also known as a "PCU"), which is connected to the first electric generator MG1, the second electric generator MG2, and the battery BAT. For example, the power conversion device 11 is configured to include a first inverter 111, a second inverter 112, and a voltage control device 110. The first inverter 111, the second inverter 112, and the voltage control device 110 are electrically connected.

[0047] The voltage control device 110 converts the input voltage and outputs the converted voltage. A DC / DC converter or similar device can be used as the voltage control device 110. For example, when power from the battery BAT is supplied to the first electric generator MG1, the voltage control device 110 boosts the output voltage of the battery BAT and outputs it to the first inverter 111. Alternatively, when the first electric generator MG1 is generating electricity regeneratively, the voltage control device 110 steps down the output voltage of the first electric generator MG1 received via the first inverter 111 and outputs it to the battery BAT. Furthermore, when the second electric generator MG2 is generating electricity, the voltage control device 110 steps down the output voltage of the second electric generator MG2 received via the second inverter 112 and outputs it to the battery BAT.

[0048] When the first inverter 111 supplies power from the battery BAT to the first electric generator MG1, it converts the DC power received from the battery BAT via the voltage control device 110 into AC power and outputs it to the first electric generator MG1. Additionally, when the first electric generator MG1 performs regenerative power generation, the first inverter 111 converts the AC power received from the first electric generator MG1 into DC power and outputs it to the voltage control device 110. Furthermore, when the first inverter 111 processes the regenerative power from the first electric generator MG1, it converts the AC power received from the first electric generator MG1 into DC power and outputs it to the second inverter 112.

[0049] When the second electric generator MG2 generates electricity, the second inverter 112 converts the power (AC) received from the second electric generator MG2 into DC and outputs it to the voltage control device 110. Additionally, when the second inverter 112 is processing the regenerated power from the first electric generator MG1, it converts the regenerated power (DC) received from the first electric generator MG1 via the first inverter 111 into AC and outputs it to the second electric generator MG2.

[0050] A battery AT (Battery Actuator) is a rechargeable secondary battery consisting of multiple individual cells connected in series or parallel. A battery AT is configured to output high voltages, such as 100V to 400V. Lithium-ion batteries, nickel-metal hydride batteries, etc., can be used as the individual cells in a battery AT.

[0051] The clutch CL can be in an engaged state, connecting (engaging) the power transmission path from the engine ENG to the drive wheel DW, and in an disengaged state, disconnecting (cutting off) the power transmission path from the engine ENG to the drive wheel DW. The output of the engine ENG is transmitted to the drive wheel DW when the clutch CL is engaged, and not transmitted to the drive wheel DW when the clutch CL is disengaged.

[0052] The various sensors 12 include, for example, a vehicle speed sensor for detecting the driving speed of the vehicle 10 (hereinafter also referred to as "vehicle speed"), an accelerator position (hereinafter also referred to as "AP") sensor for detecting the amount of operation performed on the accelerator pedal of the vehicle 10, and a battery sensor for detecting various information related to the battery BAT (such as the output voltage, charging and discharging current, and temperature of the battery BAT). The detection results of the various sensors 12 are sent to the control device 20 as detection signals.

[0053] The navigation device 13 includes a storage device (e.g., flash memory) for storing map data, a Global Navigation Satellite System (GNSS) receiver capable of determining the position of the vehicle 10 (hereinafter also referred to as "vehicle position") based on signals received from positioning satellites, a display for displaying various information, and operation buttons (including a touch panel) for accepting operations from users (occupants of the vehicle 10, such as the driver; the same applies to the following description).

[0054] The map data stored in the navigation device 13 includes road data related to roads. For example, in the road data, each road is divided into a defined interval. The road data includes information about the route corresponding to each interval and information about the nodes connecting the routes to each other. In addition, the road data includes attribute information corresponding to each route, such as the distance to the interval corresponding to that route, speed limit (e.g., legal speed), road gradient (e.g., inclination angle), etc.

[0055] The navigation device 13 determines, for example, the path (hereinafter also referred to as the "guided path") from the current location of the vehicle 10, i.e. the vehicle's current location, to the destination set by the user of the vehicle 10, by referring to map data, and displays the determined guided path on the display to guide the user.

[0056] In addition, the navigation device 13 predicts the predetermined driving path of the vehicle 10 by referring to the vehicle's position, the vehicle's direction of travel, the set destination, map data, etc. As an example, the navigation device 13 predicts the predetermined driving path as an interval within a specified range from the vehicle's position to the direction of travel (i.e., ahead) of the vehicle 10.

[0057] When predicting a predetermined driving route, the navigation device 13 sends route information about the predetermined driving route to the control device 20. This route information includes information about each section included in the predetermined driving route and attribute information about each section. Therefore, the navigation device 13 can notify the control device 20 of each section included in the predetermined driving route, as well as the speed limits, road gradients, etc., for that section. In addition, the navigation device 13 also appropriately notifies the control device 20 of the vehicle's current location.

[0058] Furthermore, the navigation device 13 can also be configured to receive road traffic information, including congestion information, and send the received road traffic information to the control device 20. Thus, the navigation device 13 can notify the control device 20 of congestion conditions along a predetermined travel route.

[0059] Display device 14 is a display device capable of displaying various information related to vehicle 10, such as a liquid crystal display known as a "multi-function information display". The information displayed by display device 14 includes information indicating the remaining capacity of battery BAT (hereinafter also referred to as "remaining capacity information"). In this embodiment, the remaining capacity information is presented in several stages (e.g., 10 stages) to roughly indicate the remaining capacity of battery BAT (see below). Figure 7 , Figure 8 (etc.). Therefore, by checking the remaining capacity information displayed on the display device 14, the user can roughly know the remaining capacity of the battery BAT at this time. In addition, the display device 14 is not limited to an LCD display, but may also be a lamp display, etc.

[0060] The control device 20 is implemented, for example, through an electronic control unit (ECU), which is a device (computer) that provides unified control of the entire vehicle 10. This ECU includes a processor for performing various calculations, a storage device for storing various information, and input / output devices for controlling the input and output of internal and external data of the control device 20. The control device 20 can be implemented by one ECU or by multiple ECUs.

[0061] Specifically, the control device 20 is configured to communicate with the engine ENG, clutch CL, power conversion device 11, various sensors 12, navigation device 13, and display device 14. Furthermore, the control device 20 controls the output of the first electric generator MG1 and the second electric generator MG2, or the state of the clutch CL, by controlling the output of the engine ENG, or by controlling the power conversion device 11. Thus, as described later, the control device 20 can control the driving mode of the vehicle 10. Additionally, the control device 20 also controls the display device 14 to display remaining capacity information corresponding to the current remaining capacity of the battery BAT.

[0062] [Vehicle Driving Mode]

[0063] Next, the driving modes of vehicle 10 will be described. Vehicle 10 can use EV driving mode, hybrid driving mode, and engine driving mode as its driving modes. Moreover, vehicle 10 can drive by using any of these driving modes. The control device 20 controls which driving mode vehicle 10 drives in.

[0064] [EV Driving Mode]

[0065] The EV driving mode is a driving mode in which the vehicle 10 is driven by power supplied solely by the battery BAT to the first electric generator MG1, and the first electric generator MG1 outputs power based on that power. This EV driving mode is an example of the first driving mode in this invention.

[0066] Specifically, in EV driving mode, the control device 20 disengages the clutch CL. Furthermore, in EV driving mode, the control device 20 stops supplying fuel to the engine ENG, thereby stopping the power output from the engine ENG (hereinafter also referred to as "engine ENG operation"). Therefore, in EV driving mode, the second electric generator MG2 does not generate electricity. Moreover, in EV driving mode, the control device 20 only supplies power from the battery BAT to the first electric generator MG1, causing the corresponding power to be output from the first electric generator MG1, which then propels the vehicle 10.

[0067] The control device 20, for example, enables the vehicle 10 to drive in EV driving mode under the condition that the first electric generator MG1 is supplied with only the power of the battery BAT and the driving force required for the vehicle 10 to drive is obtained by the power output by the first electric generator MG1 based on the power of the battery BAT.

[0068] Furthermore, in EV driving mode, fuel supply to the engine ENG is stopped. Therefore, compared to other driving modes that supply fuel to the engine ENG, the engine ENG consumes less fuel, thus improving the fuel economy of vehicle 10. Therefore, by increasing the frequency (opportunities) of setting vehicle 10 to EV driving mode, it is possible to improve the fuel economy of vehicle 10. On the other hand, in EV driving mode, the second electric generator MG2 does not generate electricity; the first electric generator MG1 is driven solely by the power from the battery BAT. Therefore, the remaining capacity (SOC: also known as State of charge) of the battery BAT is easily reduced.

[0069] [Hybrid Driving Mode]

[0070] The hybrid driving mode is a driving mode in which the power generated by the second electric generator MG2 is supplied to the first electric generator MG1, and the vehicle 10 is driven primarily by the power output from the first electric generator MG1 based on this power. This hybrid driving mode is an example of the second driving mode in this invention.

[0071] Specifically, in hybrid driving mode, the control device 20 disengages the clutch CL. Furthermore, in hybrid driving mode, the control device 20 supplies fuel to the engine ENG, causing power to be output from the engine ENG, and the power from the engine ENG drives the second electric generator MG2. Thus, in hybrid driving mode, the second electric generator MG2 generates electricity. Additionally, in hybrid driving mode, the control device 20 disconnects the power transmission path via the clutch CL, supplying the electricity generated by the second electric generator MG2 to the first electric generator MG1, causing the corresponding power to be output from the first electric generator MG1, and using this power to propel the vehicle 10.

[0072] The power supplied from the second electric generator MG2 to the first electric generator MG1 is greater than the power supplied from the battery BAT to the first electric generator MG1. Therefore, in hybrid driving mode, compared with EV driving mode, the output of the first electric generator MG1 can be increased, and a larger driving force can be obtained as the driving force for driving the vehicle 10 (hereinafter also referred to as "the output of the vehicle 10").

[0073] Furthermore, in hybrid driving mode, the control device 20 can also supply power from the battery BAT to the first electric generator MG1 as needed. That is, in hybrid driving mode, the control device 20 can also supply power from both the second electric generator MG2 and the battery BAT to the first electric generator MG1. Thus, compared to the case where only the power from the second electric generator MG2 is supplied to the first electric generator MG1, the power supplied to the first electric generator MG1 can be increased, and greater driving force can be obtained as the output of the vehicle 10.

[0074] [Engine Driving Mode]

[0075] The engine driving mode is a driving mode in which the vehicle 10 is driven primarily by the power output of the engine ENG. This engine driving mode is another example of the second driving mode in this invention.

[0076] Specifically, in engine driving mode, the control device 20 engages the clutch CL. Additionally, in engine driving mode, the control device 20 supplies fuel to the engine ENG and outputs power from the engine ENG. In engine driving mode, since the clutch CL engages the power transmission path, the power from the engine ENG is transmitted to the drive wheels DW, thereby driving the drive wheels DW. Thus, in engine driving mode, the control device 20 outputs power from the engine ENG and uses this power to propel the vehicle 10.

[0077] Furthermore, in engine driving mode, the control device 20 can also supply power from the battery BAT to the first electric generator MG1 as needed. Therefore, in engine driving mode, the vehicle 10 can be driven using the power output from the first electric generator MG1 supplied with power from the battery BAT, resulting in greater driving force compared to driving the vehicle 10 solely using the engine ENG. Additionally, compared to driving the vehicle 10 solely using the engine ENG, the output of the engine ENG can be suppressed, thus improving the fuel economy of the vehicle 10.

[0078] [Control modes related to EV driving mode]

[0079] Next, the control modes (hereinafter also referred to as "control modes") related to the EV driving mode in vehicle 10 will be described. As control modes, vehicle 10 can adopt a normal mode and an EV expansion mode that makes the driving frequency in the EV driving mode higher than that in the normal mode. This EV expansion mode is an example of the expansion mode in this invention.

[0080] For example, the vehicle 10 is equipped with an operation button (not shown, hereinafter also referred to as the "EV expansion mode setting button") for setting the control mode to EV expansion mode. By operating this EV expansion mode setting button, the user can request the control device 20 to be set to EV expansion mode (hereinafter also referred to as the "EV expansion request"). Based on the EV expansion request, the control device 20 sets the control mode to EV expansion mode. On the other hand, if there is no EV expansion request, the control device 20 presets the control mode to normal mode.

[0081] When the control mode is EV extended mode, the control device 20 can operate in EV driving mode if the remaining capacity of the battery BAT is above the specified EV extended mode lower limit threshold. Specifically, when the control mode is EV extended mode, if the required driving force of the vehicle 10 is less than the specified EV release output threshold and the remaining capacity of the battery BAT is above the EV extended mode lower limit threshold, the control device 20 enables the vehicle 10 to operate in EV driving mode.

[0082] Here, a value corresponding to the upper limit of the power output that the first electric generator MG1 can produce based solely on the power supply from the battery BAT is set as the EV release output threshold. Additionally, a value that prevents the battery BAT from becoming over-discharged is set as the EV extended mode lower limit threshold.

[0083] In EV Extended Mode, compared to Normal Mode, driving in EV mode is possible even when the remaining capacity of the battery (BAT) is low, as detailed later. Therefore, the frequency of driving in EV mode is higher in EV Extended Mode than in Normal Mode.

[0084] Furthermore, after the EV extended mode is set, even if the user does not perform the prescribed cancellation operation using the aforementioned EV extended mode setting button, the control device 20 will automatically deactivate the EV extended mode and return to the normal mode at a predetermined time. Therefore, even if the user forgets to perform the cancellation operation or does not know how to cancel it, the control device 20 will automatically return to the normal mode, thus avoiding the prolonged use of the EV extended mode, which places a greater burden on the battery (BAT), against the user's wishes.

[0085] On the other hand, if the EV extended mode is automatically and frequently deactivated, users who wish to continue in EV extended mode will face the cumbersome process of resetting to EV extended mode each time. Such cumbersome operation can lead to user dissatisfaction with vehicle 10 and may become a major reason for the reduced marketability of vehicle 10. Therefore, the control device 20 can appropriately continue in EV extended mode by performing the following controls to improve the marketability of vehicle 10.

[0086] [Example of continuing in EV extended mode]

[0087] First, refer to Figure 2 An example illustrating the scenario where EV expansion mode continues will be provided. Figure 2 In (A), the horizontal axis represents time, and the vertical axis represents the required driving force (i.e., the driving force required for the vehicle 10 to move). Additionally, in Figure 2 In (B) of the diagram, the horizontal axis represents time, and the vertical axis represents the remaining capacity of the battery (BAT). Furthermore, Figure 2 (C) in the text indicates the control mode at each time point. Figure 2 (D) in the text represents the driving mode at each time point.

[0088] like Figure 2 As shown, at time t10, the control mode is set to EV extended mode. In addition, during the period from time t10 to time t11, the driving force is required to remain approximately constant at a value less than the EV release output threshold. Although the remaining capacity of the battery BAT gradually decreases, it remains above the lower limit threshold of EV extended mode. Therefore, the control device 20 enables the vehicle 10 to drive in EV driving mode (shown as driving mode "EV" in the figure).

[0089] Starting at time t11, the accelerator pedal of vehicle 10 is pressed forcefully, thus requiring an increase in driving force. At time t12, after time t11, the required driving force exceeds the EV release output threshold. Therefore, when the required driving force exceeds the EV release output threshold, the control device 20 activates the engine ENG (i.e., terminates the EV driving mode) and switches to another driving mode that ensures the required driving force output of vehicle 10. Here, as an example, it switches to hybrid driving mode (shown as driving mode "HV"). By switching to hybrid driving mode, the battery BAT can also be charged using the electricity generated by the second electric generator MG2 driven by the engine ENG.

[0090] Furthermore, when the engine ENG operates due to the required driving force exceeding the EV release output threshold, the control device 20 determines, based on the remaining capacity of the battery BAT at that time, whether to continue the EV extended mode after the engine ENG operates (i.e., after the EV driving mode ends). In this determination, if the remaining capacity of the battery BAT is above a predetermined lower limit threshold, the control device 20 determines to continue the EV extended mode; if the remaining capacity of the battery BAT is less than the lower limit threshold, it determines not to continue the EV extended mode (i.e., to release the EV extended mode). Here, a value larger than the aforementioned EV extended mode lower limit threshold is set as the lower limit threshold. The lower limit threshold will be described again later.

[0091] exist Figure 2 In the example shown, since the remaining capacity of the battery BAT at time t12 is above the lower limit threshold, the control device 20 determines to continue the EV extended mode. Therefore, the control device 20 continues the EV extended mode even after the engine ENG starts operating (i.e., the EV driving mode ends) at time t12. Furthermore, while continuing the EV extended mode, if the driving force is required to fall below the EV release output threshold again after time t12, the control device 20 stops the engine ENG, allowing the vehicle 10 to resume operation in EV driving mode (refer to time t13).

[0092] Additionally, when the control mode is EV extended mode and the vehicle 10 is driving in EV driving mode, if the required driving force does not exceed the EV release output threshold, the control device 20 enables the vehicle 10 to drive in EV driving mode and maintains the EV extended mode setting until the remaining capacity of the battery BAT is less than the EV extended mode lower limit threshold (refer to the period from time t13 to time t14).

[0093] Furthermore, when the remaining capacity of the battery BAT is less than the lower limit threshold of the EV extended mode, the control device 20 activates the engine ENG (i.e., terminates the EV driving mode) and switches to another driving mode that can suppress the decrease in the remaining capacity of the battery BAT (refer to time t14). This prevents excessive reduction in the remaining capacity of the battery BAT. Here, as an example, the mode is switched to hybrid driving mode.

[0094] In addition, in cases where the remaining capacity of the battery BAT is less than the lower limit threshold of the EV extended mode and the engine ENG is activated, the control device 20 also deactivates the EV extended mode along with the activation of the engine ENG (i.e. the end of the EV driving mode), and restores the control mode to the normal mode.

[0095] As explained above, if the remaining capacity of the battery BAT when the engine ENG is operating is above the lower limit threshold due to the required driving force exceeding the EV deactivation output threshold, the control device 20 continues in EV extended mode thereafter. This reduces the chance of automatically deactivating EV extended mode and decreases the need for user intervention to reset to EV extended mode. Furthermore, in the example described above, the switch from EV driving mode to hybrid driving mode is set at times t12 and t14, but it is also possible to switch to engine driving mode instead of hybrid driving mode.

[0096] [Examples of situations where EV extended mode is not continued]

[0097] Next, refer to Figure 3 An example is given for cases where the EV expansion mode is not continued. Figure 3 The example shown is similar to Figure 2 The difference in the example shown is that, at time t12 when the engine ENG operates due to the required driving force exceeding the EV release output threshold, the remaining capacity of the battery BAT is less than the maintenance lower limit threshold. In the following... Figure 3 In the explanation, with Figure 2 The examples shown focus on explaining the different parts, while omitting explanations of the common parts as appropriate.

[0098] like Figure 3 As shown, when the remaining capacity of the battery (BAT) is less than the lower limit threshold due to the required driving force exceeding the EV release output threshold, the control device 20 determines that the EV expansion mode should not continue. Therefore, in Figure 3 In the example shown, the control device 20 deactivates the EV extended mode at the moment t12 when the engine ENG is activated (i.e., the EV driving mode is terminated).

[0099] Furthermore, when the EV extended mode is deactivated in this manner, the control device 20 charges the battery BAT while driving the vehicle 10 in a driving mode other than EV driving mode (i.e., with the engine ENG running) until the remaining capacity of the battery BAT reaches the prescribed upper limit threshold of the EV extended mode (see reference). Figure 3 (The period from time t12 to time t21). Here, the upper limit threshold of the EV extended mode is greater than the lower limit threshold of the EV extended mode. For example, the upper limit threshold of the EV extended mode is set considering the remaining capacity of the battery BAT, which can continue driving in EV mode for a certain period of time. As a result, the remaining capacity of the battery BAT when driving in EV mode is started can be prepared in advance to a state that can continue driving in EV mode for a certain period of time, and the phenomenon of starting the engine ENG multiple times in a short period of time (hereinafter also referred to as "frequent engine starts") can be avoided.

[0100] Here, refer to Figure 4 Examples of situations where the engine starts frequently will be explained. Figure 4 The example shown is similar to Figure 2 and Figure 3 The difference in the example shown is that, although the remaining capacity of the battery BAT is less than the lower limit threshold at time t12 when the engine ENG operates due to the required driving force exceeding the EV release output threshold, the EV extended mode continues. In the following... Figure 4 In the explanation, with Figure 2 and Figure 3 The examples shown focus on explaining the different parts, while omitting explanations of the common parts as appropriate.

[0101] like Figure 4 As shown, even though the remaining capacity of the battery BAT at time t12 is less than the lower limit threshold, the vehicle continues in EV extended mode. Later, when the required driving force again falls below the EV release output threshold, the control device 20 stops the engine ENG, causing the vehicle 10 to resume EV driving mode (refer to time t13). As a result, after the start of EV driving mode, the remaining capacity of the battery BAT falls below the lower limit threshold of EV extended mode within a short period, causing the engine ENG to start again (refer to time t31). This results in frequent engine starts.

[0102] Noise and vibration are generated, especially during engine (ENG) startup. Therefore, from an NV (Noise, Vibration) perspective, frequent engine starts could reduce the marketability of vehicle 10. Thus, when the remaining capacity of battery (BAT) during engine (ENG) operation is less than the lower limit threshold due to the required driving force exceeding the EV deactivation output threshold, the control device 20 deactivates the EV amplification mode, thereby preventing frequent engine starts and improving the marketability of vehicle 10.

[0103] [Maintain the lower threshold]

[0104] Next, the lower limit threshold will be explained. The higher the lower limit threshold, the easier it is to automatically deactivate the EV expansion mode; the lower the lower limit threshold, the more likely frequent engine starts will occur. Frequent deactivation of the EV expansion mode and frequent engine starts can both reduce the marketability of the vehicle 10. Therefore, it is desirable to set an appropriate lower limit threshold that can prevent both frequent engine starts and frequent deactivation of the EV expansion mode.

[0105] Therefore, the control device 20 is configured to change the lower limit threshold based on at least one of the vehicle speed and the road gradient of the road on which the vehicle 10 is traveling. Thus, an appropriate lower limit threshold can be set.

[0106] Here, refer to Figure 5 This section provides specific examples of changes to the minimum threshold for maintaining vehicle speed and road gradient. Furthermore, in... Figure 5 In the diagram, the horizontal axis represents vehicle speed, and the vertical axis represents the set range. Here, the set range refers to the difference between the lower limit threshold and the upper limit threshold of the EV expanded mode. That is, the smaller the set range, the closer the lower limit threshold is to the upper limit threshold of the EV expanded mode. Conversely, the larger the set range, the further the lower limit threshold is from the upper limit threshold of the EV expanded mode.

[0107] The control device 20 has a pre-stored representation. Figure 5 Information regarding features 501 to 503 is shown. Here, feature 501 represents the setting range corresponding to each vehicle speed when the road gradient is a first predetermined value (e.g., a reference value). Furthermore, feature 502 represents the setting range corresponding to each vehicle speed when the road gradient is a second predetermined value greater than the first predetermined value. Moreover, feature 503 represents the setting range corresponding to each vehicle speed when the road gradient is a third predetermined value less than the first predetermined value.

[0108] For example, if the road gradient of the road on which vehicle 10 is traveling is a first predetermined value and the vehicle speed is v1, then control device 20 sets the value obtained by adding the corresponding set amplitude, x1, to the EV extended mode lower limit threshold as the lower limit threshold. On the other hand, if the road gradient of the road on which vehicle 10 is traveling is a second predetermined value and the vehicle speed is v1, then control device 20 sets the value obtained by adding the corresponding set amplitude, x2, to the EV extended mode lower limit threshold as the lower limit threshold. Here, x2 is greater than x1. Therefore, the lower limit threshold set when the vehicle speed is v1 and the road gradient is the second predetermined value is greater than the lower limit threshold set when the vehicle speed is the same and the road gradient is the first predetermined value.

[0109] On the other hand, if the road gradient of the road on which vehicle 10 is traveling is a third predetermined value and the vehicle speed is v1, the control device 20 sets the value obtained by adding the corresponding set amplitude, x3, to the EV extended mode lower limit threshold as the lower limit threshold. Here, x3 is less than x1. Therefore, the lower limit threshold set when the vehicle speed is v1 and the road gradient is the third predetermined value is less than the lower limit threshold set when the vehicle speed is the same and the road gradient is the first predetermined value.

[0110] That is, if the road gradient increases, the driving resistance also increases, so when the vehicle 10 is driving in EV mode, the remaining capacity of the battery BAT decreases faster. Therefore, if the same lower limit threshold is used when the road gradient is large as when the road gradient is small (i.e., when the driving resistance is small), frequent engine starts are likely to occur. Therefore, the control device 20 can suppress frequent engine starts by increasing the lower limit threshold as the road gradient increases.

[0111] Conversely, if the road gradient decreases, the driving resistance also decreases, so when the vehicle 10 is driving in EV mode, the remaining capacity of the battery BAT decreases more slowly. Therefore, when the road gradient is low, even if the lower limit threshold is reduced to a certain extent, frequent engine starts are less likely to occur. Therefore, by making the lower limit threshold decrease as the road gradient decreases, the control device 20 can prevent frequent engine starts and make it less likely for the EV extended mode to automatically deactivate.

[0112] Furthermore, if the road gradient of the road on which vehicle 10 is traveling is a first predetermined value, and the vehicle speed is v2, which is greater than v1, then the control device 20 sets the value obtained by adding the corresponding set amplitude x4 to the EV extended mode lower limit threshold as the lower limit threshold. Here, x4 is greater than x1. Therefore, the lower limit threshold set when the road gradient is the first predetermined value and the vehicle speed is v2 is greater than the lower limit threshold set when the road gradient is the same and the vehicle speed is v1.

[0113] That is, as the vehicle speed increases, similar to when the road gradient increases, the driving resistance increases. Conversely, as the vehicle speed decreases, the driving resistance decreases. Therefore, by increasing the lower limit threshold as the vehicle speed increases, the control device 20 can suppress frequent engine starts. Furthermore, by decreasing the lower limit threshold as the vehicle speed decreases, the control device 20 can prevent frequent engine starts and make it less likely for the EV amplification mode to automatically deactivate.

[0114] Furthermore, the control device 20 can, for example, obtain information from the navigation device 13 indicating the road gradient of the road on which the vehicle 10 is traveling. Alternatively, the control device 20 may use any method to obtain information indicating the road gradient of the road on which the vehicle 10 is traveling.

[0115] Furthermore, the control device 20 can also determine, based on a predetermined driving path of the vehicle 10, whether the recovery of the remaining capacity of the battery BAT can be foreseen when the vehicle 10 is traveling on that predetermined driving path. Moreover, the control device 20 can also reduce the lower limit threshold when it is determined that the recovery of the remaining capacity of the battery BAT can be foreseen, compared to when it is determined that the recovery of the remaining capacity of the battery BAT cannot be foreseen.

[0116] Here, the determination of whether the recovery of the remaining capacity of the battery BAT can be foreseen can be, for example, set as whether the range in which the first electric generator MG1 can perform regeneration operation (hereinafter also referred to as the "regeneration range") is included in the predetermined driving path of the vehicle 10. An example of a regeneration range is a downhill road where the elevation of the end point on the side away from the vehicle 10 is lower than the elevation of the end point on the side closer to the vehicle 10, i.e., the start point.

[0117] Here, refer to Figure 6 This section provides a specific example of changing the lower limit threshold for maintaining the predetermined driving path of vehicle 10. Figure 6 In (A) of the graph, the horizontal axis represents time, and the vertical axis represents elevation. Additionally, in... Figure 6 In (B) of the diagram, the horizontal axis represents time and the vertical axis represents the set amplitude.

[0118] exist Figure 6In the example shown, vehicle 10 travels on path R1. Here, path R1 is the path predicted as the predetermined travel path of vehicle 10, including the regeneration interval Rs1. In this case, starting from a predetermined time t41 before vehicle 10 arrives at the start of the regeneration interval Rs1, control device 20 decreases a set amplitude at a predetermined reduction rate. Simultaneously, the lower limit threshold also decreases at a predetermined reduction rate. Time t41 can be, for example, set to the time when vehicle 10 arrives at a location a predetermined distance from the start of the regeneration interval Rs1. Furthermore, at time t42 when vehicle 10 arrives at the start of the regeneration interval Rs1, control device 20 has a set amplitude that causes the lower limit threshold to become a predetermined minimum value.

[0119] Thus, when the recovery of the remaining capacity of the battery (BAT) can be anticipated based on the predetermined driving path of the vehicle 10, the control device 20 can easily continue the EV extended mode by reducing the lower limit threshold, thereby increasing the driving frequency in the EV driving mode. This reduces the opportunities for engine (ENG) operation, thereby improving the fuel economy of the vehicle 10 and suppressing the deterioration of NV characteristics caused by engine (ENG) operation. Furthermore, by increasing the driving frequency in the EV driving mode before the vehicle 10 reaches the regeneration zone, reducing the remaining capacity of the battery (BAT), more regenerated electricity generated in the regeneration zone can be recovered, achieving efficient utilization of regenerated electricity.

[0120] [Example of displaying remaining capacity information]

[0121] As mentioned above, in vehicle 10, the remaining capacity of battery BAT when the EV extended mode is deactivated is not constant. That is, the remaining capacity when the EV extended mode is deactivated can be the remaining capacity just below the lower threshold of the EV extended mode, or it can be the remaining capacity above the lower threshold of the EV extended mode but below the lower threshold of the maintenance mode. However, although the remaining capacity of battery BAT when the EV extended mode is deactivated varies in this way, if the display method of the remaining capacity information when the EV extended mode is deactivated is also incorrect, it may confuse the user or cause discomfort.

[0122] Therefore, the control device 20 displays the remaining capacity information in the same way in the following two cases: when the vehicle 10 is driven in EV driving mode, the EV extended mode is deactivated because the required driving force is above the EV deactivation output threshold and the remaining capacity of the battery BAT is less than the maintenance lower threshold; and when the vehicle 10 is driven in EV driving mode, the EV extended mode is deactivated because the remaining capacity of the battery BAT is less than the EV extended mode lower threshold.

[0123] For example, such as Figure 7As shown at time t51, when the control device 20 deactivates the EV expansion mode because the remaining capacity of the battery BAT is less than the EV expansion mode lower limit threshold while the vehicle 10 is driving in EV driving mode, it displays the remaining capacity information as "1 (e.g., 1 in stage 10)".

[0124] In addition, such as Figure 8 As shown at time t61, when the control device 20 is driving the vehicle 10 in EV driving mode, it also displays the remaining capacity information as "1" because the driving force is required to be above the EV release output threshold and the remaining capacity of the battery BAT is less than the maintenance lower limit threshold.

[0125] That is, just before time t61, because the remaining capacity of the battery BAT is greater than the lower limit threshold of the EV extended mode, the remaining capacity information is sometimes expressed as, for example, "2" (e.g., 2 in stage 10). In such cases, after the control device 20 changes to the remaining capacity information expressing "1" at time t61, it starts the engine ENG and deactivates the EV extended mode. This avoids user confusion or discomfort caused by deviations in the display of remaining capacity information when the EV extended mode is deactivated.

[0126] As explained above, the control device 20 is configured to set an EV expansion mode that increases the driving frequency in EV driving mode according to requests from the user of vehicle 10. Furthermore, when set to EV expansion mode, if the required driving force is less than a predetermined EV release output threshold and the remaining capacity of the battery BAT is above a predetermined EV expansion mode lower limit threshold, the control device 20 keeps vehicle 10 in EV driving mode. Additionally, when set to EV expansion mode and vehicle 10 is in EV driving mode, if the required driving force reaches or exceeds the EV release output threshold, the control device 20 activates the engine ENG, thereby allowing the vehicle to drive in other driving modes (e.g., hybrid driving mode). Furthermore, if the remaining capacity of the battery BAT when the required driving force reaches or exceeds the EV release output threshold is above a lower limit threshold (above the EV expansion mode lower limit threshold), the control device 20 continues in EV expansion mode. On the other hand, if the remaining capacity of the battery BAT when the required driving force reaches or exceeds the EV release output threshold is less than the lower limit threshold, the control device 20 deactivates EV expansion mode. Thus, EV expansion mode can be appropriately continued, thereby improving the marketability of vehicle 10.

[0127] Furthermore, the present invention is not limited to the embodiments described above, and can be appropriately modified and improved. For example, in the embodiments described above, an example was given in which the control device 20 changes the lower limit threshold based on both vehicle speed and road slope, but it is not limited thereto. The control device 20 may also be configured to change the lower limit threshold based only on either vehicle speed or road slope.

[0128] At least the following items are described in this specification. Furthermore, the components corresponding to the above embodiments are shown in parentheses, but the present invention is not limited thereto.

[0129] (1) A vehicle control device (control device 20) for controlling a vehicle (vehicle 10), the vehicle comprising an internal combustion engine (engine ENG), an energy storage device (battery BAT), an electric motor (first electric generator MG1) driven at least according to a power supply from the energy storage device, and drive wheels (drive wheels DW) driven by at least one of the internal combustion engine and the electric motor.

[0130] in,

[0131] The vehicle has a first driving mode and a second driving mode. In the first driving mode, the vehicle moves by stopping the internal combustion engine and driving the drive wheels with power supplied from the energy storage device. In the second driving mode, the internal combustion engine is activated for driving.

[0132] The vehicle control device is configured to set an extended mode that increases the driving frequency in the first driving mode according to requests from the user of the vehicle.

[0133] When the vehicle control device is set to the extended mode, if the required driving force for the vehicle is less than a specified value (EV release output threshold) and the remaining capacity of the battery storage device is above the specified extended mode lower limit threshold (EV extended mode lower limit threshold), the vehicle will operate in the first driving mode.

[0134] When the vehicle control device is set to the expanded mode and the vehicle is driven in the first driving mode, if the required driving force is above the predetermined value, it activates the internal combustion engine to drive the vehicle in the second driving mode, and...

[0135] If the remaining capacity is above a predetermined minimum threshold when the required driving force is above the specified value, the vehicle control device continues the expansion mode; conversely, if the remaining capacity is below the minimum threshold, the vehicle control device deactivates the expansion mode.

[0136] The lower limit threshold is maintained at a value greater than the upper limit threshold of the expansion mode.

[0137] According to (1), when the vehicle is set to extended mode and driven in the first driving mode, if the remaining capacity of the energy storage device required to reach a specified value or higher is greater than the lower limit threshold of the extended mode, the extended mode can continue; otherwise, if it is less than the lower limit threshold, the extended mode can be deactivated. Thus, the extended mode can be appropriately continued, thereby improving the vehicle's marketability.

[0138] (2) The vehicle control device according to (1), wherein,

[0139] The vehicle control device is configured to change the lower limit threshold based on the vehicle's travel speed.

[0140] When the driving speed is low, the lower limit threshold is reduced compared to when the driving speed is high.

[0141] According to (2), when the vehicle speed is low, the lower limit threshold is reduced compared to when the speed is high, so frequent engine starts can be avoided and the expanded mode can be automatically deactivated against the user's wishes. Frequent engine starts refer to the phenomenon that the internal combustion engine starts multiple times in a short period of time.

[0142] (3) The vehicle control device according to (1) or (2), wherein,

[0143] The vehicle control device is configured to change the lower limit threshold based on the road gradient of the road on which the vehicle is traveling.

[0144] When the road slope is relatively small, the lower limit threshold is reduced compared to when the road slope is relatively large.

[0145] According to (3), when the road gradient of the road on which the vehicle is driving is small, the lower limit threshold is reduced compared with the case of a large road gradient. Therefore, it is possible to avoid frequent engine starts and make the expanded mode less likely to be automatically deactivated against the user's wishes. Frequent engine starts refer to the phenomenon that the internal combustion engine starts multiple times in a short period of time.

[0146] (4) The vehicle control device according to (1), wherein,

[0147] The vehicle control device is configured to change the lower limit threshold based on a predetermined driving path of the vehicle.

[0148] If it is determined that the recovery of the remaining capacity can be foreseen when the vehicle is traveling on the predetermined travel path, the lower limit threshold is reduced compared to the case where the recovery of the remaining capacity cannot be foreseen.

[0149] According to (4), by reducing the lower limit threshold when the recovery of the remaining capacity of the energy storage device can be anticipated based on the vehicle's predetermined driving path, compared to when the recovery of the remaining capacity of the energy storage device cannot be anticipated, it is easier to continue expanding the mode and increase the driving frequency in the first driving mode. As a result, the opportunities for the internal combustion engine to operate can be reduced, thereby improving the vehicle's fuel economy and suppressing the deterioration of NV (Noise, Vibration) characteristics caused by the operation of the internal combustion engine.

[0150] (5) The vehicle control device according to any one of (1) to (4), wherein,

[0151] When the vehicle is in the expanded mode and is driving in the first driving mode, if the remaining capacity is less than the lower limit threshold of the expanded mode, the internal combustion engine is activated to drive the vehicle in the second driving mode, and the expanded mode is deactivated.

[0152] According to (5), when the vehicle is set to the extended mode and driven in the first driving mode, if the remaining capacity of the energy storage device is less than the lower limit threshold of the extended mode, the internal combustion engine is turned on and the vehicle is driven in the second driving mode, and the extended mode is deactivated, thus avoiding excessive reduction of the remaining capacity of the energy storage device.

[0153] (6) The vehicle control device according to (5), wherein,

[0154] The vehicle is equipped with a display device (display device 14) that can display remaining capacity information indicating the remaining capacity.

[0155] The vehicle control device displays the remaining capacity information in the display device in the same way in the following two situations:

[0156] When the vehicle is driven in the first driving mode, the expanded mode is deactivated because the required driving force is above the specified value and the remaining capacity is below the lower limit threshold; and

[0157] When the vehicle is driven in the first driving mode, the expanded mode is deactivated because the remaining capacity is less than the lower limit threshold of the expanded mode.

[0158] According to (6), it is possible to avoid user confusion or discomfort caused by deviations in the display of remaining capacity information when the expanded mode is deactivated.

[0159] (7) The vehicle control device according to any one of (1) to (6), wherein,

[0160] The vehicle also includes a generator (second electric generator MG2), which is driven by the internal combustion engine to generate electricity and can supply the generated electricity to the electric motor.

[0161] The second driving mode is a driving mode in which the drive wheels are driven by the electric motor at least according to the power supply from the generator.

[0162] According to (7), even if the remaining capacity of the energy storage device decreases, the generator can be driven by the internal combustion engine, and the electric motor can be driven by the power generated by the generator, thereby enabling the vehicle to move.

Claims

1. A vehicle control device for controlling a vehicle, the vehicle comprising an internal combustion engine, an electric storage device, an electric motor driven at least according to a power supply from the electric storage device, and drive wheels driven by at least one of the internal combustion engine and the electric motor. in, The vehicle has a first driving mode and a second driving mode. In the first driving mode, the vehicle moves by stopping the internal combustion engine and driving the drive wheels with power supplied from the energy storage device. In the second driving mode, the internal combustion engine is activated for driving. The vehicle control device is configured to set an extended mode that increases the driving frequency in the first driving mode according to requests from the user of the vehicle. When the vehicle control device is set to the extended mode, if the required driving force for the vehicle's operation is less than a specified value and the remaining capacity of the energy storage device is above the specified extended mode lower limit threshold, the vehicle will operate in the first driving mode. When the vehicle control device is set to the expanded mode and the vehicle is driven in the first driving mode, if the required driving force is above the predetermined value, it activates the internal combustion engine to drive the vehicle in the second driving mode, and... If the remaining capacity is above a predetermined minimum threshold when the required driving force is above the specified value, the vehicle control device continues the expansion mode; conversely, if the remaining capacity is below the minimum threshold, the vehicle control device deactivates the expansion mode. The lower limit threshold is maintained at a value greater than the upper limit threshold of the expansion mode.

2. The vehicle control device according to claim 1, wherein, The vehicle control device is configured to change the lower limit threshold based on the vehicle's travel speed. The lower limit threshold is reduced as the driving speed decreases.

3. The vehicle control device according to claim 1 or 2, wherein, The vehicle control device is configured to change the lower limit threshold based on the road gradient of the road on which the vehicle is traveling. The lower limit threshold is reduced as the road slope decreases.

4. The vehicle control device according to claim 1, wherein, The vehicle control device is configured to change the lower limit threshold based on a predetermined driving path of the vehicle. If it is determined that the recovery of the remaining capacity can be foreseen when the vehicle is traveling on the predetermined travel path, the lower limit threshold is reduced compared to the case where the recovery of the remaining capacity cannot be foreseen.

5. The vehicle control device according to any one of claims 1, 2, and 4, wherein, When the vehicle is in the expanded mode and is driving in the first driving mode, if the remaining capacity is less than the lower limit threshold of the expanded mode, the internal combustion engine is activated to drive the vehicle in the second driving mode, and the expanded mode is deactivated.

6. The vehicle control device according to claim 5, wherein, The vehicle is equipped with a display device capable of displaying remaining capacity information indicating the remaining capacity. The vehicle control device displays the remaining capacity information in the display device in the same way in the following two situations: When the vehicle is driven in the first driving mode, the expanded mode is deactivated because the required driving force is above the specified value and the remaining capacity is less than the lower limit threshold. as well as When the vehicle is driven in the first driving mode, the expanded mode is deactivated because the remaining capacity is less than the lower limit threshold of the expanded mode.

7. The vehicle control device according to any one of claims 1, 2, 4, and 6, wherein, The vehicle also includes a generator, which is driven by the internal combustion engine to generate electricity and can supply the generated electricity to the electric motor. The second driving mode is a driving mode in which the drive wheels are driven by the electric motor at least according to the power supply from the generator.

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