Vehicle control device

Abstract

The present application provides a vehicle control device capable of avoiding a decrease in driving performance and suppressing deterioration of an electrical storage device. A control device (100) is capable of performing motor assist that supplies electric power of a battery (BAT) to a motor (MOT) and assists driving of a drive wheel (DW) by the motor (MOT) when a vehicle (1) is running by driving the drive wheel (DW) by an engine (ENG). Also, the control device (100) is capable of changing an upper limit assist electric power, which is an upper limit value of electric power supplied from the battery (BAT) to the motor (MOT) for performing the motor assist, according to a temperature of the battery (BAT), and in a case where the temperature of the battery (BAT) reaches a first temperature, limiting the upper limit assist electric power in a manner that an amount of decrease in maximum driving force of the vehicle (1) converges within an allowable range.

Description

TECHNICAL FIELD

[0001] The present application relates to a vehicle control device. BACKGROUND

[0002] In recent years, there is a hybrid electric vehicle that has an internal combustion engine and an electric motor as a drive source that drives a drive wheel. In such a hybrid electric vehicle, there is also a hybrid electric vehicle that assists the drive of the drive wheel with the electric motor by appropriately supplying electric power of an electric storage device to the electric motor. In addition, in the following Patent Literature 1, a technology is disclosed that can change the maximum allowable electric power (i.e., input / output limit of the battery) when charging and discharging the battery based on the temperature of the battery.

[0003] [Patent Literature]

[0004] [Patent Literature]

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2019-094013 SUMMARY

[0006] [Problems to be Solved by the Invention]

[0007] However, when the driving force of the electric motor is used for the drive of the drive wheel, if the electric power supplied from the electric storage device to the electric motor is reduced, the driving force for driving the drive wheel (i.e., the driving force for running the vehicle) sharply decreases, which can cause discomfort to the driver and result in a decrease in drivability.

[0008] The present application provides a vehicle control device that can avoid a decrease in drivability and suppress degradation of an electric storage device.

[0009] [Means for Solving the Problems]

[0010] The present application provides a vehicle control device that controls a vehicle that has an internal combustion engine, an electric storage device, an electric motor that is driven at least in accordance with electric power supplied from the electric storage device, and a drive wheel that is driven by at least one of the internal combustion engine and the electric motor, wherein

[0011] The vehicle control device can execute motor assist that supplies electric power of the electric storage device to the electric motor and assists the drive of the drive wheel by the electric motor when the vehicle is running by driving the drive wheel by the internal combustion engine,

[0012] The vehicle control device can change an upper limit assist electric power in accordance with the temperature of the electric storage device, the upper limit assist electric power being an upper limit value of electric power supplied from the electric storage device to the electric motor in order to execute the motor assist,

[0013] The vehicle control device limits the upper limit assist electric power in a manner such that a decrease in the maximum driving force of the vehicle converges within an allowable range, in a case where the temperature of the electric storage device reaches a first temperature.

[0014] [Effects of Invention]

[0015] According to the present application, it is possible to provide a vehicle control device that can avoid a decrease in driving performance and suppress deterioration of an electric storage device. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a view that shows the schematic configuration of a vehicle that is provided with a vehicle control device of one embodiment of the present application.

[0017] Figure 2 is a view that shows the content of each travel mode.

[0018] Figure 3 is a view that shows a control example of the upper limit assist electric power.

[0019] Figure 4 is a view that shows a control example of the upper limit regenerative electric power.

[0020] REFERENCE NUMERALS

[0021] 1 vehicle

[0022] 100 control device (vehicle control device)

[0023] DW drive wheels

[0024] BAT storage battery (electric storage device)

[0025] ENG engine (internal combustion engine)

[0026] MOT motor (electric motor) DETAILED DESCRIPTION

[0027] First, with reference to Figure 1 , a vehicle 1 that is provided with a control device 100 that is one embodiment of a vehicle control device of the present application will be described. As shown in Figure 1 , the vehicle 1 of the present embodiment is provided with a drive device 10 that outputs the driving force of the vehicle 1, and the control device 100 that is responsible for the control of the entire vehicle 1 including the drive device 10.

[0028] [Drive Device]

[0029] As shown in Figure 1As shown, the drive device 10 is provided with an engine ENG that is one example of an internal combustion engine, a generator GEN that is one example of a generator, a motor MOT that is one example of an electric motor, a transmission T, and a case 11 that houses the generator GEN, the motor MOT, and the transmission T. The motor MOT and the generator GEN are connected to a battery BAT provided in the vehicle 1, and can perform power supply from the battery BAT and energy regeneration to the battery BAT. The battery BAT is one example of an electric power storage device.

[0030] [Transmission]

[0031] In the case 11, a transmission housing chamber 11a that houses the transmission T and a motor housing chamber 11b that houses the motor MOT and the generator GEN are provided on the engine ENG side in the axial direction.

[0032] In the transmission housing chamber 11a, an input shaft 21, a generator shaft 23, a motor shaft 25, a countershaft 27, and a differential mechanism D are housed in parallel with each other.

[0033] The input shaft 21 is arranged coaxially with a crankshaft 12 of the engine ENG side by side. The driving force of the crankshaft 12 is transmitted to the input shaft 21 via a damper that is not shown. A generator drive gear 32 that constitutes a generator gear train Gg is provided on the input shaft 21.

[0034] On the input shaft 21, on the engine side with respect to the generator drive gear 32, a low-speed side drive gear 34 that constitutes a low-speed side engine gear train GLo is provided via a first clutch CL1, and on the side opposite to the engine side (hereinafter, referred to as a motor side), a high-speed side drive gear 36 that constitutes a high-speed side engine gear train GHi is provided. The first clutch CL1 is a hydraulic clutch for linking the input shaft 21 and the low-speed side drive gear 34 in a manner capable of being engaged and disengaged, and is a so-called multi-plate type friction clutch.

[0035] On the generator shaft 23, a generator driven gear 40 that meshes with the generator drive gear 32 is provided. The generator drive gear 32 of the input shaft 21 and the generator driven gear 40 of the generator shaft 23 constitute a generator gear train Gg for transmitting the rotation of the input shaft 21 to the generator shaft 23. The generator GEN is arranged on the motor side of the generator shaft 23. The generator GEN is configured to have a rotor R that is fixed to the generator shaft 23, and a stator S that is fixed to the case 11 and is arranged in opposition to the rotor R on the outer diameter side of the rotor R.

[0036] The rotation of the input shaft 21 is transmitted to the generator shaft 23 via the generator gear train Gg, whereby the rotor R of the generator GEN is rotated by the rotation of the generator shaft 23. Thus, at the time of driving of the engine ENG, the power of the engine ENG input from the input shaft 21 can be converted into electric power by the generator GEN.

[0037] A motor drive gear 52 constituting a motor gear train Gm is provided on the motor shaft 25. On the motor shaft 25, a motor MOT is disposed at a position on the motor side of the motor drive gear 52. The motor MOT is configured to have a rotor R fixed to the motor shaft 25 and a stator S fixed to the case 11 and disposed in opposition to the rotor R on the outer diameter side of the rotor R.

[0038] On the countershaft 27, a low-speed side driven gear 60 is provided in order on the engine side, which is engaged with the low-speed side drive gear 34, an output gear 62 engaged with the ring gear 70 of the differential mechanism D, a high-speed side driven gear 64 engaged with the high-speed side drive gear 36 of the input shaft 21 via the second clutch CL2, and a motor driven gear 66 engaged with the motor drive gear 52 of the motor shaft 25. The second clutch CL2 is a hydraulic clutch for linking the countershaft 27 and the high-speed side driven gear 64 in an engageable and disengageable manner, and is a so-called multi-plate type friction clutch.

[0039] A low-speed side engine gear train GLo for transmitting the rotation of the input shaft 21 to the countershaft 27 is constituted by the low-speed side drive gear 34 of the input shaft 21 and the low-speed side driven gear 60 of the countershaft 27. In addition, a high-speed side engine gear train GHi for transmitting the rotation of the input shaft 21 to the countershaft 27 is constituted by the high-speed side drive gear 36 of the input shaft 21 and the high-speed side driven gear 64 of the countershaft 27. Here, the reduction ratio of the low-speed side engine gear train GLo including the low-speed side drive gear 34 and the low-speed side driven gear 60 is larger than the reduction ratio of the high-speed side engine gear train GHi including the high-speed side drive gear 36 and the high-speed side driven gear 64.

[0040] Therefore, by engaging the first clutch CL1 and releasing the second clutch CL2 at the time of driving of the engine ENG, the driving force of the engine ENG is transmitted to the countershaft 27 via the low-speed side engine gear train GLo at a large reduction ratio. On the other hand, by releasing the first clutch CL1 and engaging the second clutch CL2 at the time of driving of the engine ENG, the driving force of the engine ENG is transmitted to the countershaft 27 via the high-speed side engine gear train GHi at a smaller reduction ratio. Note that the first clutch CL1 and the second clutch CL2 are not engaged at the same time.

[0041] In addition, a motor gear train Gm for transmitting the rotation of the motor shaft 25 to the countershaft 27 is constituted by the motor drive gear 52 of the motor shaft 25 and the motor driven gear 66 of the countershaft 27. When the rotor R of the motor MOT rotates, the rotation of the motor shaft 25 is transmitted to the countershaft 27 via the motor gear train Gm. Thus, when the motor MOT is driven, the driving force of the motor MOT is transmitted to the countershaft 27 via the motor gear train Gm.

[0042] In addition, a final drive gear train Gf for transmitting the rotation of the countershaft 27 to the differential mechanism D is constituted by the output gear 62 of the countershaft 27 and the ring gear 70 of the differential mechanism D. Thus, the driving force of the motor MOT input to the countershaft 27 via the motor gear train Gm, the driving force of the engine ENG input to the countershaft 27 via the low-speed engine gear train GLo, and the driving force of the engine ENG input to the countershaft 27 via the high-speed engine gear train GHi are transmitted to the differential mechanism D via the final drive gear train Gf, and are transmitted from the differential mechanism D to the axle DS. Thus, the driving force for running the vehicle 1 is output via a pair of drive wheels DW provided at both ends of the axle DS.

[0043] The thus-constituted drive device 10 has a power transmission path that transmits the driving force of the motor MOT to the axle DS (i.e., the drive wheels DW), a low-speed power transmission path that transmits the driving force of the engine ENG to the axle DS, and a high-speed power transmission path that transmits the driving force of the engine ENG to the axle DS. Thus, as will be described later, the vehicle 1 on which the drive device 10 is mounted can adopt a plurality of running modes such as an EV running mode in which the vehicle 1 runs using the power output by the motor MOT (i.e., the driving force of the motor MOT), a hybrid running mode, a low-speed engine running mode in which the vehicle 1 runs using the power output by the engine ENG (i.e., the driving force of the engine ENG), and a high-speed engine running mode.

[0044] The control device 100 acquires vehicle information related to the vehicle 1 on the basis of detection signals and the like received from various sensors (not shown) provided in the vehicle 1, and controls the drive device 10 on the basis of the acquired vehicle information. As the sensors provided in the vehicle 1, there can be mentioned a vehicle speed sensor that detects the rotational speed of the axle DS, an accelerator position sensor (hereinafter, also referred to as an AP sensor) that detects the operation amount of an accelerator pedal of the vehicle 1, a brake sensor that detects the operation amount of a brake pedal of the vehicle 1, an engine speed sensor that detects the rotational speed of the engine ENG (hereinafter, also referred to as the engine speed), a battery sensor that detects the state of the battery BAT (for example, the voltage between the terminals of the battery BAT, the charge / discharge current, the temperature), and the like.

[0045] The vehicle information includes information indicating a running state of the vehicle 1. As the running state of the vehicle 1, there can be mentioned a vehicle speed (hereinafter, also referred to as a vehicle speed) of the vehicle 1, an AP opening degree indicating an operation amount of an accelerator pedal (i.e., an accelerator position) possessed by the vehicle 1, a required driving force (hereinafter, also referred to as a required driving force) required for running of the vehicle 1, an engine speed, and the like.

[0046] The vehicle speed can be acquired on the basis of a detection signal from a vehicle speed sensor. The AP opening degree can be acquired on the basis of a detection signal from an AP sensor. The engine speed can be acquired on the basis of a detection signal from an engine speed sensor. The required driving force can be derived on the basis of the vehicle speed, the AP opening degree, and the like.

[0047] In addition, the vehicle information also includes battery information related to a battery BAT possessed by the vehicle 1. The battery information includes information indicating a state of charge (SOC) of the battery BAT, i.e., a remaining capacity of the battery BAT. Hereinafter, the SOC of the battery BAT is also referred to as a battery SOC. The battery SOC can be derived on the basis of a detection signal (e.g., a voltage between terminals of the battery BAT, a charge / discharge current) from a battery sensor.

[0048] Also, the battery information includes information indicating a temperature of the battery BAT detected by the battery sensor. Hereinafter, the temperature of the battery BAT is also referred to as a battery temperature. In addition, the battery information can also include information such as a voltage between terminals of the battery BAT, a charge / discharge current, and the like, detected by the battery sensor.

[0049] The control device 100 controls the driving device 10 on the basis of the vehicle information (i.e., the running state of the vehicle 1, the battery information). Specifically, the control device 100 controls the driving force of the vehicle 1 (i.e., the output of the driving device 10) with the required driving force derived on the basis of the vehicle speed, the AP opening degree (i.e., the output request received from the driver) as a target value. Note that, in the following description, the upper limit value of the driving force of the vehicle 1 is also referred to as a maximum driving force.

[0050] In addition, the control device 100 causes the vehicle 1 to run in any one of a plurality of running modes (described later) that the vehicle 1 can adopt by controlling the driving device 10 on the basis of the vehicle information.

[0051] In controlling the driving device 10, the control device 100 controls the driving of the engine ENG by controlling the fuel supply to the engine ENG, or controls the driving of the motor MOT by controlling the power supply from the generator GEN, the battery BAT to the motor MOT, or controls the power generation of the generator GEN by controlling the field current flowing through the coil of the generator GEN, and the like.

[0052] Furthermore, when controlling the drive unit 10, the control device 100 releases or engages the first clutch CL1 by controlling an actuator (not shown) that actuates the first clutch CL1. Similarly, the control device 100 releases or engages the second clutch CL2 by controlling an actuator (not shown) that actuates the second clutch CL2.

[0053] In this way, the control device 100 can enable the vehicle 1 to operate in any of the multiple driving modes described later by controlling the engine ENG, generator GEN, motor MOT, first clutch CL1, and second clutch CL2. It should be noted that the control device 100 is implemented, for example, by an ECU (Electronic Control Unit) equipped with a processor, memory, interface, etc.

[0054] [Driver modes that the vehicle can use]

[0055] Next, refer to Figure 2 The driving mode table Ta shown describes the driving modes that vehicle 1 can use. For example... Figure 2 As shown, vehicle 1 can adopt EV driving mode, hybrid driving mode, low-speed side engine driving mode and high-speed side engine driving mode.

[0056] [EV Driving Mode]

[0057] EV driving mode is a driving mode in which the battery (BAT) supplies power to the motor (MOT), and the motor (MOT) drives the vehicle 1 based on the power output of that power.

[0058] Specifically, in EV driving mode, the control device 100 releases both the first clutch CL1 and the second clutch CL2. Additionally, in EV driving mode, the control device 100 stops injecting fuel into the engine ENG, thereby stopping the engine ENG from outputting power. Furthermore, in EV driving mode, the control device 100 supplies power from the battery BAT to the motor MOT, causing the motor MOT to output power corresponding to that power (illustrated as "battery drive" of the motor). Thus, in EV driving mode, the vehicle 1 travels using the power output by the motor MOT based on the power supplied from the battery BAT.

[0059] It should be noted that in EV driving mode, as mentioned above, the power output from the engine ENG is stopped, and both the first clutch CL1 and the second clutch CL2 are released. Therefore, in EV driving mode, no power is input to the generator GEN, and no power generation based on the generator GEN is performed (the diagram shows the generator "stopping power generation").

[0060] [Hybrid Driving Mode]

[0061] The hybrid running mode is a running mode in which at least electric power is supplied from the generator GEN to the motor MOT, and the vehicle 1 is caused to run by power output from the motor MOT based on the electric power.

[0062] Specifically, in the hybrid running mode, the control device 100 releases both the first clutch CL1 and the second clutch CL2. In addition, in the hybrid running mode, the control device 100 causes the engine ENG to output power by injecting fuel into the engine ENG. The power output from the engine ENG is input to the generator GEN via the generator gear train Gg. Thus, power generation based on the generator GEN is performed.

[0063] Furthermore, in the hybrid running mode, the control device 100 supplies electric power obtained by power generation of the generator GEN to the motor MOT, and causes the motor MOT to output power corresponding to the electric power (illustrated as "generator drive" of the motor). The electric power supplied from the generator GEN to the motor MOT is greater than the electric power supplied from the battery BAT to the motor MOT. Therefore, in the hybrid running mode, as compared with the EV running mode, the power output from the motor MOT (the driving force of the motor MOT) can be increased, and a greater driving force can be obtained as the driving force of the vehicle 1 (the maximum driving force).

[0064] Note that, in the hybrid running mode, the control device 100 can also supply electric power from the battery BAT to the motor MOT as needed. That is, the control device 100 can supply electric power to the motor MOT from both the generator GEN and the battery BAT in the hybrid running mode. Thus, as compared with a case in which electric power is supplied to the motor MOT only from the generator GEN, the electric power supplied to the motor MOT can be increased, and therefore the power output from the motor MOT can be further increased, and a greater driving force can be obtained as the driving force of the vehicle 1 (the maximum driving force).

[0065] [Low-speed side engine running mode]

[0066] The low-speed side engine running mode is a running mode in which the vehicle 1 is caused to run by transmitting the power output from the engine ENG to the drive wheels DW via the low-speed side power transmission path.

[0067] Specifically, in the case of the low-speed engine travel mode, the control device 100 injects fuel to the engine ENG to cause the engine ENG to output power. In addition, in the case of the low-speed engine travel mode, the control device 100 engages the first clutch CL1 and, on the other hand, disengages the second clutch CL2. Thus, in the low-speed engine travel mode, the power output from the engine ENG is transmitted to the drive wheels DW via the low-speed engine gear train GLo, the final drive gear train Gf, and the differential mechanism D, and thus the vehicle 1 travels.

[0068] In addition, in the case of the low-speed engine travel mode, the power output from the engine ENG is also input to the generator GEN via the generator gear train Gg, but control is performed so that power generation based on the generator GEN is not performed. For example, in the low-speed engine travel mode, by causing a switching element provided on a power transmission path between the generator GEN and the battery BAT (for example, a switching element of an inverter device provided between the generator GEN and the battery BAT) to be turned off, control is performed so that power generation based on the generator GEN is not performed. Thus, in the low-speed engine travel mode, it is possible to reduce the loss due to power generation by the generator GEN, and it is possible to reduce the amount of heat generated by the generator GEN and the like. In addition, in the low-speed engine travel mode, at the time of braking of the vehicle 1, regenerative power generation based on the motor MOT can also be performed, and the power generated by the power generation is used to charge the battery BAT.

[0069] In addition, in the case of the low-speed engine travel mode, the control device 100 can supply power from the battery BAT to the motor MOT as needed. Thus, in the low-speed engine travel mode, it is also possible to cause the vehicle 1 to travel using the power output by the motor MOT based on the power supplied from the battery BAT, and it is possible to obtain greater driving force as the driving force (maximum driving force) of the vehicle 1 compared to the case where the vehicle 1 is caused to travel only by the power of the engine ENG.

[0070] [High-speed engine travel mode]

[0071] The high-speed engine travel mode is a travel mode in which the vehicle 1 is caused to travel by transmitting the power output from the engine ENG to the drive wheels DW via a high-speed power transmission path.

[0072] Specifically, in the case of the high-speed engine travel mode, the control device 100 injects fuel to the engine ENG to cause the engine ENG to output power. Also, in the case of the high-speed engine travel mode, the control device 100 engages the second clutch CL2, and on the other hand, disengages the first clutch CL1. Thus, in the high-speed engine travel mode, the power output from the engine ENG is transmitted to the drive wheels DW via the high-speed engine gear train GHi, the final drive gear train Gf, and the differential mechanism D, and thus the vehicle 1 travels.

[0073] Also, in the case of the high-speed engine travel mode, the power output from the engine ENG is also input to the generator GEN via the generator gear train Gg, but control is performed so that power generation based on the generator GEN is not performed. Thus, in the high-speed engine travel mode, it is possible to reduce the loss due to power generation by the generator GEN, and it is possible to reduce the amount of heat generated by the generator GEN and the like. Also, in the high-speed engine travel mode, during braking of the vehicle 1, it is also possible to perform regenerative power generation based on the motor MOT, and the power obtained by power generation is used to charge the battery BAT.

[0074] Also, in the case of the high-speed engine travel mode, the control device 100 can supply power from the battery BAT to the motor MOT as needed. Thus, in the high-speed engine travel mode, it is also possible to cause the vehicle 1 to travel using the power output by the motor MOT based on the power supplied from the battery BAT, and it is possible to obtain greater driving force as the driving force (maximum driving force) of the vehicle 1 compared to the case where the vehicle 1 is caused to travel by only the power of the engine ENG.

[0075] Note that, hereinafter, the case where, in the low-speed engine travel mode, the high-speed engine travel mode, and the like, the vehicle 1 is caused to travel by driving the drive wheels DW by the engine ENG, power is supplied from the battery BAT to the motor MOT, and the motor MOT assists in driving the drive wheels DW (i.e., the travel of the vehicle 1) will also be referred to as motor assist.

[0076] Hereinafter, the driving force of the motor MOT that drives the drive wheels DW during motor assist will also be referred to as an assist amount. Also, hereinafter, the upper limit value of the assist amount will also be referred to as an upper limit assist amount. Also, hereinafter, the power supplied from the battery BAT to the motor MOT in order to perform motor assist will also be referred to as assist power. Also, hereinafter, the upper limit value of the assist power will also be referred to as an upper limit assist power. The upper limit assist amount depends on the upper limit assist power.

[0077] [Limitation on the upper limit assist power (i.e., the upper limit assist amount)]

[0078] The battery BAT generates heat when supplying electric power to the motor MOT. Therefore, a battery cooling device (not shown) that cools the battery BAT is provided in the vehicle 1. However, depending on the size of the electric power (for example, assist electric power) supplied from the battery BAT to the motor MOT, there is a case where the amount of heat generated by the battery BAT exceeds the amount of cooling by the battery cooling device, and in such a case, the battery temperature rises. In order to suppress the deterioration of the battery BAT, it is preferable to avoid the battery BAT from entering a high temperature state, and to use the battery BAT in an appropriate temperature range.

[0079] As a method of avoiding the battery BAT from entering a high temperature state, it is considered that in a case where the battery temperature reaches a prescribed temperature in the electric power supply from the battery BAT to the motor MOT, the electric power supply from the battery BAT to the motor MOT is stopped at that time. In this way, it is possible to avoid the battery temperature from rising beyond the prescribed temperature. However, in a case where the battery temperature reaches the prescribed temperature in the motor assist, if the assist electric power (that is, the assist amount) is set to 0 at that time, the driving force of the vehicle 1 sharply decreases, and it is possible to cause the driver to feel discomfort, resulting in a decrease in the drivability.

[0080] Therefore, the control device 100 limits the upper limit assist electric power (that is, the upper limit assist amount) in a manner such that the decrease in the maximum driving force of the vehicle 1 converges within the allowable range in a case where the battery temperature reaches the first temperature. Here, the first temperature is determined in advance by the manufacturer or the like of the control device 100 as a temperature that becomes a condition for starting to suppress the rise in the temperature of the battery BAT. For example, the first temperature can be set to 38 [°C].

[0081] In addition, here, the allowable range is determined in advance by the manufacturer or the like of the control device 100 in consideration of the influence on the drivability that occurs accompanying the decrease in the maximum driving force of the vehicle 1. For example, the allowable range is a range in which the maximum driving force of the vehicle 1 before the battery temperature reaches the first temperature (that is, normally) is reduced by 20% or less.

[0082] Specifically, the control device 100 decreases the upper limit assist electric power to electric power that is greater than 0 (zero) and smaller than the upper limit assist electric power before the battery temperature reaches the first temperature in a case where the battery temperature reaches the first temperature. Thereby, even in a case where the battery temperature reaches the first temperature in the motor assist, it is possible to suppress the rise in the battery temperature thereafter, and to continue the motor assist. Therefore, it is possible to avoid a case where the motor assist is suddenly ended and the driving force of the vehicle 1 sharply decreases when the battery temperature reaches the first temperature in the motor assist.

[0083] Thus, the control device 100, in a case where the battery temperature reaches the first temperature, limits the upper limit assist electric power while taking into account the amount of reduction in the maximum driving force of the vehicle 1, and is able to avoid a sharp drop in the driving force of the vehicle 1, and suppress an increase in the battery temperature. Therefore, the control device 100 is able to avoid a reduction in the drivability, and suppress deterioration of the battery BAT.

[0084] [Specific limitation example of upper limit assist electric power (i.e., upper limit assist amount)]

[0085] Next, with reference to Figure 3 , a specific limitation example of the upper limit assist electric power (i.e., upper limit assist amount) will be described. In Figure 3 , the horizontal axis indicates the vehicle speed [km / h], and the vertical axis indicates the driving force [N] of the vehicle 1. Note that the driving force of the vehicle 1 in a case where the vehicle speed is equal to or higher than a prescribed v0 is shown in Figure 3 . Here, v0 is a speed at which the control device 100 is able to cause the vehicle 1 to travel in the high-speed engine traveling mode, and can be set to 100 [km / h], for example.

[0086] In Figure 3 , the driving force F11 indicates the maximum driving force of the vehicle 1 in the high-speed engine traveling mode at ordinary times (i.e., when the control device 100 does not perform limitation of the upper limit assist electric power based on the battery temperature), and the driving force F12 indicates the driving force at which the driving force F11 is reduced to a limit allowed by the allowable range (for example, 20% of the driving force F11 is reduced).

[0087] Further, in Figure 3 , the driving force F13 indicates the maximum driving force of the vehicle 1 in the high-speed engine traveling mode in a case where the motor assist is not performed (i.e., in a case where the vehicle 1 is caused to travel by only the driving force of the engine ENG), and the driving force F14 indicates the maximum driving force of the vehicle 1 in the high-speed engine traveling mode in a case where the motor assist is performed using the prescribed assist electric power (i.e., assist amount) at the time of the battery BAT thermal equilibrium.

[0088] Here, the battery BAT thermal equilibrium refers to a case where the amount of heat generation of the battery BAT and the amount of cooling of the battery cooling device become equivalent. That is, the control device 100 is able to reduce the battery temperature by causing the electric power supplied from the battery BAT to the motor MOT in the high-speed engine traveling mode to be less than the prescribed assist electric power at the time of the battery BAT thermal equilibrium, in other words, by causing the maximum driving force of the vehicle 1 in the high-speed engine traveling mode to be less than the driving force F14.

[0089] Further, in Figure 3In this case, the driving force F21 indicates the maximum driving force of the vehicle 1 in the hybrid running mode in a case where electric power is supplied to the motor MOT from both the generator GEN and the storage battery BAT. The driving force F22 indicates the maximum driving force of the vehicle 1 in the hybrid running mode in a case where electric power is supplied to the motor MOT only from the generator GEN.

[0090] The control device 100 reduces the upper limit assist electric power (i.e., the upper limit assist amount) so that the maximum driving force of the vehicle 1 in the high-speed engine running mode becomes the driving force F12, in a case where the storage battery temperature is equal to or higher than the first temperature and lower than the second temperature. The amount of reduction of the upper limit assist electric power at this time is set in advance in the control device 100 by the manufacturer or the like of the control device 100. Also, the second temperature is determined in advance by the manufacturer or the like of the control device 100. For example, the second temperature can be set to 40 [°C].

[0091] Note that even if the maximum driving force of the vehicle 1 in the high-speed engine running mode is made the driving force F12, the reduction of the maximum driving force of the vehicle 1 can be suppressed by causing the vehicle 1 to run in the hybrid running mode during a period in which the driving force F21 is greater than the driving force F12 (i.e., during a period in which the vehicle speed < v1). Figure 3 In this case, the vehicle speed < v1. Figure 3 In this case, the vehicle speed < v1.

[0092] Also, the control device 100 can change the upper limit assist electric power (i.e., the upper limit assist amount) in accordance with the vehicle speed. In this way, the control device 100 can cause the upper limit assist electric power (i.e., the upper limit assist amount) to gradually change in accordance with the vehicle speed, and can suppress a sharp change in the driving force of the vehicle 1 that can cause a reduction in the drivability.

[0093] Specifically, the control device 100 reduces the upper limit assist electric power as the vehicle speed increases after the vehicle speed reaches a prescribed v2 in a state in which the storage battery temperature reaches the second temperature, and sets the upper limit assist electric power to 0 in a case where the vehicle speed reaches a prescribed v3 (where v3 > v2) in a state in which the storage battery temperature reaches the second temperature.

[0094] Here, v2 is a speed determined in advance by the manufacturer or the like of the control device 100, and can be set to 150 [km / h], for example, and v2 is one example of the first speed. Here, v3 is a speed determined in advance by the manufacturer or the like of the control device 100, and can be set to 170 [km / h], for example, and v3 is one example of the second speed.

[0095] Thus, as Figure 3As indicated by a hatched arrow β, the control device 100 can cause the driving force of the vehicle 1 to gradually decrease as the vehicle speed increases to approach the driving force F13 after the vehicle speed reaches v2 in the state where the battery temperature reaches the second temperature. Thus, the control device 100 can suppress a sharp change in the driving force of the vehicle 1 that can cause a decrease in the drivability.

[0096] Note that the control device 100 can also set the upper limit assist power to 0 at the time when the battery temperature reaches a prescribed third temperature (for example, 45 [°C]) that is higher than the second temperature before the vehicle speed reaches v3. In this case, the battery temperature can be prevented from rising above the third temperature.

[0097] [Limitation of upper limit regenerative power]

[0098] The battery BAT can be charged by regenerative power generation of the motor MOT in conjunction with braking of the vehicle 1, but also generates heat at the time of charging. Moreover, if the power (hereinafter referred to as regenerative power) obtained by the regenerative power generation supplied from the motor MOT to the battery BAT is large, the amount of heat generated by the battery BAT exceeds the amount of cooling by the battery cooling device, and the battery temperature rises. When the battery BAT enters a high-temperature state, as described above, the control device 100 limits the upper limit assist power (i.e., the upper limit assist amount), and thus the driving force of the vehicle 1 can decrease.

[0099] Therefore, in order to prevent the battery BAT from entering a high-temperature state and to appropriately charge the battery BAT by the regenerative power of the motor MOT, the control device 100 can also change the upper limit value of the power that the motor MOT can obtain by regenerative power generation, i.e., the upper limit regenerative power, according to the vehicle speed. Hereinafter, a control example of the upper limit regenerative power of the control device 100 will be described. Figure 4

[0100] In Figure 4 , the horizontal axis indicates the vehicle speed [km / h], and the vertical axis indicates the power [kW] that can be supplied from the battery BAT to the motor MOT per unit time. Note that in Figure 4 , a case where the power that can be supplied from the battery BAT to the motor MOT per unit time is less than 0 [kW] indicates the upper limit regenerative power that can be supplied from the motor MOT to the battery BAT per unit time.

[0101] As indicated in Figure 4 , the control device 100 sets the upper limit regenerative power to P1 until the vehicle speed reaches a prescribed V4 (where V4 < V2). Here, v4 is a speed that is determined in advance by the manufacturer or the like of the control device 100, and can be set to 100 [km / h], for example, and v4 is one example of the third speed. In addition, P1 is the rated input power of the battery BAT, for example.​

[0102] Further, if the vehicle speed reaches V4 or more, the control device 100 gradually decreases the upper limit regenerative electric power to a prescribed P2 (where P2 < PI) as the vehicle speed increases. Here, P2 is, for example, the upper limit regenerative electric power at which the amount of heat generated in the battery BAT charged by the regenerative electric power of the motor MOT is equal to or less than the amount of cooling by the battery cooling device.

[0103] Thus, the control device 100 sets the upper limit regenerative electric power to P2 (i.e., decreases to less than PI) in the case where the vehicle speed is V4 or more and lower than V2, and thereby can suppress the increase in the battery temperature. Therefore, the control device 100 can suppress the decrease in the driving force of the vehicle 1 due to the limitation of the upper limit assist electric power (i.e., the upper limit assist amount), while charging the battery BAT with the regenerative electric power. In addition, the control device 100 sets the upper limit regenerative electric power to PI before the vehicle speed reaches V4, and thereby recovers the regenerative electric power as much as possible, and thereby can charge the battery BAT.

[0104] As described above, according to the control device 100, it is possible to avoid the decrease in the drivability, and suppress the deterioration of the battery BAT.

[0105] Note that the present application is not limited to the above-described embodiments, and can be appropriately modified, improved, or the like.

[0106] For example, in the above-described embodiments, two modes, the high-speed side engine running mode and the low-speed side engine running mode, are provided as the running modes in which the power of the engine ENG is transmitted to the drive wheels DW to run the vehicle 1, but the present application is not limited thereto. For example, only the power transmission path on the high-speed side can be provided, and thereby only the high-speed side engine running mode can be adopted as the running mode in which the power of the engine ENG is transmitted to the drive wheels DW to run the vehicle 1.

[0107] In addition, in the above-described embodiments, an example in which the upper limit assist electric power (i.e., the upper limit assist amount) of the motor assist in the high-speed side engine running mode is limited is described, but the present application is not limited thereto. For example, in the low-speed side engine running mode, the upper limit assist electric power (i.e., the upper limit assist amount) can be limited similarly to the high-speed side engine running mode of the above-described embodiments. In addition, the limited amount of the upper limit assist electric power (i.e., the upper limit assist amount) can be made different between the high-speed side engine running mode and the low-speed side engine running mode.

[0108] At least the following matters are described in this specification. Note that the corresponding components and the like in the above-described embodiments are shown in parentheses, but the present application is not limited thereto.

[0109] (1) A vehicle control device (control device 100) that controls a vehicle (vehicle 1) that is provided with an internal combustion engine (engine ENG), an electrical storage device (battery BAT), an electric motor (motor MOT) that is driven at least in accordance with electric power supplied from the electrical storage device, and a drive wheel (drive wheel DW) that is driven by at least one of the internal combustion engine and the electric motor, wherein

[0110] The vehicle control device is capable of performing motor assist that supplies electric power of the electrical storage device to the electric motor and assists driving of the drive wheel by the electric motor when the vehicle is running by driving the drive wheel by the internal combustion engine,

[0111] The vehicle control device is capable of changing an upper limit assist electric power in accordance with a temperature of the electrical storage device, the upper limit assist electric power being an upper limit value of electric power supplied from the electrical storage device to the electric motor in order to perform the motor assist,

[0112] The vehicle control device limits the upper limit assist electric power in a manner that a reduction amount of a maximum driving force of the vehicle converges within an allowable range in a case where the temperature of the electrical storage device reaches a first temperature.

[0113] According to (1), the upper limit assist electric power is limited in a manner that the reduction amount of the maximum driving force of the vehicle converges within the allowable range in a case where the temperature of the electrical storage device reaches the first temperature, so it is possible to avoid a sharp decrease in the driving force of the vehicle and suppress an increase in the temperature of the electrical storage device. Therefore, it is possible to avoid a decrease in drivability accompanying a sharp decrease in the driving force of the vehicle and suppress deterioration of the electrical storage device.

[0114] (2) The vehicle control device according to (1), wherein

[0115] The upper limit assist electric power is reduced to electric power that is greater than 0 and smaller than the upper limit assist electric power before the temperature of the electrical storage device reaches the first temperature in a case where the temperature of the electrical storage device reaches the first temperature.

[0116] According to (2), it is possible to suppress an increase in the temperature of the electrical storage device thereafter and continue the motor assist even in a case where the temperature of the electrical storage device reaches the first temperature in the motor assist.

[0117] (3) The vehicle control device according to (1) or (2), wherein

[0118] The upper limit assist electric power is capable of being changed in accordance with a speed of the vehicle.

[0119] According to (3), the upper limit assist electric power can be made to gradually change in accordance with the vehicle speed, and a sharp change in the driving force of the vehicle that can cause a reduction in the driving performance can be suppressed.

[0120] (4) The vehicle control device according to (3), wherein

[0121] the upper limit assist electric power is reduced as the vehicle speed increases after the vehicle speed reaches a first speed in a state where the temperature of the electrical storage device reaches a second temperature that is higher than the first temperature,

[0122] in a case where the vehicle speed reaches a second speed that is higher than the first speed in a state where the temperature of the electrical storage device reaches the second temperature, the upper limit assist electric power is set to 0.

[0123] According to (4), the upper limit assist electric power can be made to gradually change in accordance with the vehicle speed, and a sharp change in the driving force of the vehicle that can cause a reduction in the driving performance can be suppressed.

[0124] (5) The vehicle control device according to (4), wherein

[0125] the electric motor regeneratively generates electric power in conjunction with braking of the vehicle,

[0126] the vehicle control device is capable of changing an upper limit regenerative electric power in accordance with the vehicle speed, the upper limit regenerative electric power being an upper limit value of electric power that the electric motor can obtain through regenerative electric power generation,

[0127] the vehicle control device reduces the upper limit regenerative electric power as compared to when the vehicle speed is less than the third speed in a case where the vehicle speed is a third speed or more that is lower than the first speed.

[0128] According to (5), a case where the driving force of the vehicle is reduced due to the restriction on the upper limit assist electric power can be suppressed, and the electrical storage device can be charged using the regenerative electric power of the electric motor.

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, wherein, When the vehicle control device moves the vehicle by driving the drive wheels via the internal combustion engine, it can perform motor assistance, which supplies power from the energy storage device to the electric motor and uses the electric motor to assist in driving the drive wheels. The vehicle control device can adjust the upper limit of auxiliary power based on the temperature of the energy storage device and the speed of the vehicle. This upper limit of auxiliary power is the maximum amount of power supplied from the energy storage device to the electric motor for motor assistance. When the temperature of the energy storage device reaches a first temperature, the vehicle control device limits the upper limit of auxiliary power in a manner that brings the reduction in the vehicle's maximum driving force within an acceptable range. After the vehicle reaches a first speed when the temperature of the energy storage device reaches a second temperature higher than the first temperature, the vehicle control device reduces the upper limit of auxiliary power as the vehicle speed increases. When the temperature of the energy storage device reaches the second temperature and the vehicle speed reaches a second speed higher than the first speed, the vehicle control device sets the upper limit auxiliary power to 0.

2. The vehicle control device according to claim 1, wherein, When the temperature of the energy storage device reaches the first temperature, the vehicle control device reduces the upper limit auxiliary power to a power that is greater than 0 and less than the upper limit auxiliary power before the temperature of the energy storage device reaches the first temperature.

3. The vehicle control device according to claim 1 or 2, wherein, The electric motor generates electricity regeneratively in conjunction with the vehicle's braking. The vehicle control device can adjust the upper limit of regenerative power according to the vehicle's speed. The upper limit of regenerative power is the maximum amount of electricity that the electric motor can generate through regeneration. When the vehicle speed is at or above a third speed lower than the first speed, the vehicle control device reduces the upper limit of regenerated power compared to when the vehicle speed is less than the third speed.

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