1. A control device of a vehicle that controls the vehicle, the vehicle being capable of traveling through a plurality of traveling modes including a first traveling mode and a second traveling mode,

the first running mode is a running mode in which the drive wheels of the vehicle can be driven by the power output from the internal combustion engine and the power output by the electric motor based on the electric power supplied from the power storage device,

the second running mode is a running mode in which the drive wheels can be driven by power output by the electric motor in accordance with electric power supplied from a generator that generates electric power by power of the internal combustion engine,

wherein the control device of the vehicle includes a travel mode control unit that causes the vehicle to travel in any travel mode of the plurality of travel modes,

the running mode control unit may switch the running mode of the vehicle to the second running mode based on a detection result of a detection unit that detects an output of the power storage device and a predetermined switching threshold value when the running mode of the vehicle is changed to the first running mode,

the travel mode control unit further includes a threshold setting unit configured to set the switching threshold,

the threshold setting unit changes the value of the conversion threshold according to a maximum output of the power storage device, which is derived based on an output of the power storage device.

2. The control device of the vehicle according to claim 1,

the running mode control unit switches the running mode of the vehicle to the second running mode when the output of the power storage device exceeds the switching threshold set by the threshold setting unit when the first running mode is adopted as the running mode of the vehicle.

3. The control device of the vehicle according to claim 1 or 2,

the threshold setting unit sets a relatively high value as the conversion threshold when the maximum output of the power storage device is relatively large, and sets a relatively low value as the conversion threshold when the maximum output of the power storage device is relatively small.

4. The control device of the vehicle according to any one of claims 1 to 3,

the running mode control unit switches the running mode of the vehicle to the second running mode based on the detection result of the detection unit and the switching threshold set by the threshold setting unit when the running mode of the vehicle is set to the first running mode and the vehicle is run by the power output from the internal combustion engine and the power output from the electric motor based on the electric power supplied from the power storage device.

Background

Recent hybrid electric vehicles (hybrid electric vehicles) have a plurality of running modes including a hybrid running mode (also referred to as a series running mode) in which a generator is caused to generate electric power by engine power with a clutch disengaged and a drive wheel is driven by a motor based on at least power output from the generator, and an engine running mode in which the drive wheel is driven by at least power output from the engine with the clutch engaged (for example, see patent document 1 below).

Documents of the prior art

Patent document

Patent document 1: international publication No. 2019/003443

Disclosure of Invention

Problems to be solved by the invention

However, in patent document 1, no consideration is given to the switching from the engine running mode to the series running mode, and there is room for improvement in this point. For example, when the driving force of the vehicle decreases with a shift from the engine running mode to the series running mode, so-called "hesitation" may occur at the time of the shift, possibly resulting in a decrease in the merchantability of the vehicle.

The present invention provides a control device for a vehicle, which can appropriately switch from a first travel mode to a second travel mode, the first travel mode being a mode in which the vehicle can travel by power output from an internal combustion engine and power output by an electric motor based on electric power supplied from a power storage device, and the second travel mode being a mode in which the vehicle can travel by power output by the electric motor based on electric power supplied from a generator that generates electric power using the power of the internal combustion engine.

Means for solving the problems

The invention provides a control device for a vehicle, which controls the vehicle, the vehicle can run through a plurality of running modes including a first running mode and a second running mode,

the first running mode refers to a mode in which the drive wheels of the vehicle can be driven by the power output from the internal combustion engine and the power output by the electric motor in accordance with the electric power supplied from the power storage device,

the second running mode is a mode in which the drive wheels can be driven by power output by the electric motor in accordance with electric power supplied from a generator that generates electric power by power of the internal combustion engine,

wherein the control device of the vehicle includes a travel mode control unit that causes the vehicle to travel in any travel mode of the plurality of travel modes,

the running mode control unit may switch the running mode of the vehicle to the second running mode based on a detection result of a detection unit that detects an output of the power storage device and a predetermined switching threshold value when the running mode of the vehicle is changed to the first running mode,

the travel mode control unit further includes a threshold setting unit configured to set the switching threshold,

the threshold setting unit changes the value of the conversion threshold according to a maximum output of the power storage device, which is derived based on an output of the power storage device.

Effects of the invention

According to the present invention, it is possible to appropriately switch from the first running mode in which the vehicle can run by the power output from the internal combustion engine and the power output by the electric motor based on the electric power supplied from the power storage device to the second running mode in which the vehicle can run by the power output by the electric motor based on the electric power supplied from the generator that generates electric power using the power of the internal combustion engine.

Drawings

Fig. 1 is a diagram showing a schematic configuration of a vehicle including a vehicle control device according to an embodiment of the present invention.

Fig. 2 is a diagram showing the contents of each travel pattern.

Fig. 3 is a block diagram showing a functional configuration of the control device.

Fig. 4 is a diagram showing a relationship between the vehicle speed and the SOC and the maximum driving force of the vehicle.

Fig. 5 is a flowchart for explaining the operation of the control device.

Description of reference numerals:

1 vehicle

100 control device

120 travel mode control unit

121 detection part

122 conversion threshold setting unit (threshold setting unit)

ENG (internal combustion engine)

GEN generator (generator)

MOT motor (electric motor)

BAT battery (storage device)

DW drives the wheels.

Detailed Description

Hereinafter, one embodiment of a vehicle control device according to the present invention will be described in detail with reference to the drawings.

First, a vehicle provided with a vehicle control device according to the present invention will be described with reference to fig. 1. As shown in fig. 1, a vehicle 1 according to the present embodiment includes: a drive device 10 that outputs a drive force of the vehicle 1; and a control device 100 that governs control of the entire vehicle 1 including the drive device 10.

[ DRIVING DEVICE ]

As shown in fig. 1, the drive device 10 includes an engine ENG, a generator GEN, a motor MOT, a transmission T, and a case 11 that houses the generator GEN, the motor MOT, and the transmission T. Motor MOT and generator GEN are connected to battery BAT provided in vehicle 1, and can supply power from battery BAT and regenerate energy to battery BAT.

[ TRANSMISSION ]

In the case 11, a transmission housing chamber 11a housing the transmission T and a motor housing chamber 11b housing the motor MOT and the generator GEN are provided from the engine ENG side in the axial direction of the engine ENG.

The transmission housing chamber 11a houses an input shaft 21, a generator shaft 23, a motor shaft 25, a counter shaft 27, and a differential mechanism D, which are arranged in parallel with each other.

Input shaft 21 is arranged coaxially with crankshaft 12 of engine ENG. The driving force of the crankshaft 12 is transmitted to the input shaft 21 via a damper, not shown. The input shaft 21 is provided with a generator drive gear 32 constituting a generator gear train Gg.

The input shaft 21 is provided with a low-speed side drive gear 34 constituting a low-speed side engine gear train GLo on the engine side of the generator drive gear 32 via a first clutch CL1, and is provided with a high-speed side drive gear 36 constituting a high-speed side engine gear train GHi on the side opposite to the engine side (hereinafter referred to as the motor side). The first clutch CL1 is a hydraulic clutch for coupling the input shaft 21 and the low-speed-side drive gear 34 so as to be able to engage and disengage, and is a so-called multi-disc friction clutch.

The generator shaft 23 is provided with a generator driven gear 40 that meshes with the generator drive gear 32 of the input shaft 21. 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. A generator GEN is disposed on the motor side of the generator shaft 23. The generator GEN includes: a rotor R fixed to the generator shaft 23; and a stator S fixed to the housing 11 and disposed to face the outer diameter side of the rotor R.

By transmitting the rotation of the input shaft 21 to the generator shaft 23 via the generator gear train Gg, the rotor R of the generator GEN is rotated by the rotation of the generator shaft 23. Accordingly, when engine ENG is driven, the power of engine ENG input from input shaft 21 can be converted into electric power by generator GEN.

The motor shaft 25 is provided with a motor drive gear 52 constituting a gear train Gm for the motor. The motor MOT is disposed on the motor shaft 25 on the motor housing chamber 11b side of the motor drive gear 52. The motor MOT includes: a rotor R fixed to the motor shaft 25; and a stator S fixed to the housing 11 and disposed to face the outer diameter side of the rotor R.

The counter shaft 27 is provided with: a low-speed side driven gear 60 that meshes with the low-speed side drive gear 34; an output gear 62 that meshes with a ring gear 70 of the differential mechanism D; a high-speed side driven gear 64 that meshes with the high-speed side drive gear 36 of the input shaft 21 via a second clutch CL 2; and a motor driven gear 66 that meshes with the motor drive gear 52 of the motor shaft 25. The second clutch CL2 is a hydraulic clutch for detachably coupling the counter shaft 27 and the high-speed driven gear 64, and is a so-called multi-disc friction clutch.

The low-speed-side drive gear 34 of the input shaft 21 and the low-speed-side driven gear 60 of the counter shaft 27 constitute a gear train GLo for a low-speed-side engine for transmitting the rotation of the input shaft 21 to the counter shaft 27. Further, the high-speed-side drive gear 36 of the input shaft 21 and the high-speed-side driven gear 64 of the counter shaft 27 constitute a high-speed-side engine gear train GHi for transmitting the rotation of the input shaft 21 to the counter shaft 27. Here, the reduction gear 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 gear 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.

Therefore, by engaging the first clutch CL1 and disengaging the second clutch CL2 at the time of driving of the engine ENG, the driving force of the engine ENG is transmitted to the counter shaft 27 via the low-speed-side engine gear train GLo at a large reduction ratio. On the other hand, by disengaging 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 counter shaft 27 via the high-speed side engine gear train GHi at a small speed reduction ratio. First clutch CL1 and second clutch CL2 are not simultaneously engaged.

Further, the motor drive gear 52 of the motor shaft 25 and the motor driven gear 66 of the counter shaft 27 constitute a motor gear train Gm for transmitting the rotation of the motor shaft 25 to the counter shaft 27. When the rotor R of the motor MOT rotates, the rotation of the motor shaft 25 is transmitted to the counter shaft 27 via the gear train Gm for the motor. Thus, when the motor MOT is driven, the driving force of the motor MOT is transmitted to the counter shaft 27 through the motor gear train Gm.

Further, the output gear 62 of the counter shaft 27 and the ring gear 70 of the differential mechanism D constitute an end gear train Gf for transmitting the rotation of the counter shaft 27 to the differential mechanism D. Therefore, the driving force of the motor MOT input to the counter shaft 27 via the motor gear train Gm, the driving force of the engine ENG input to the counter shaft 27 via the low-speed side engine gear train GLo, and the driving force of the engine ENG input to the counter shaft 27 via the high-speed side engine gear train GHi are transmitted to the differential mechanism D via the final gear train Gf, and are transmitted from the differential mechanism D to the axle DS. Thus, a driving force for running vehicle 1 is output via a pair of driving wheels DW provided at both ends of axle DS.

The drive device 10 configured as described above includes: a power transmission path for transmitting the driving force of the motor MOT to the axle DS (i.e., the driving wheels DW); a low-speed-side power transmission path for transmitting the driving force of engine ENG to axle DS; and a high-speed-side power transmission path that transmits the driving force of engine ENG to axle DS. As a result, vehicle 1 mounted with drive device 10 can adopt a plurality of travel modes such as an EV travel mode in which the vehicle travels by the power output from motor MOT, a hybrid travel mode, a low-speed-side engine travel mode in which the vehicle travels by the power output from engine ENG, and a high-speed-side engine travel mode, as will be described later.

The control device 100 acquires vehicle information related to the vehicle 1 based on detection signals and the like received from various sensors provided in the vehicle 1, and controls the drive device 10 based on the acquired vehicle information.

Here, the vehicle information includes information indicating the traveling state of the vehicle 1. For example, the information indicating the traveling state of vehicle 1 includes information indicating the speed of vehicle 1 (hereinafter also referred to as vehicle speed), the AP opening degree indicating the operation amount of an accelerator pedal provided to vehicle 1 (that is, the accelerator pedal position), the required driving force of vehicle 1 derived based on the vehicle speed, the AP opening degree, and the like, the rotation speed of engine ENG (hereinafter referred to as engine rotation speed), and the like. The vehicle information also includes battery information related to a battery BAT provided in the vehicle 1. The battery information includes, for example, an output voltage (inter-terminal voltage) of the battery BAT, a charge/discharge current of the battery BAT, a temperature of the battery BAT, a state of charge (SOC) of the battery BAT derived based on the inter-terminal voltage, the charge/discharge current, and the like, and information indicating a required power required for the battery BAT. Hereinafter, the SOC of battery BAT is also referred to as battery SOC.

The control device 100 controls the drive device 10 based on the vehicle information, thereby causing the vehicle 1 to travel in any one of a plurality of travel modes that can be adopted by the vehicle 1. In controlling drive device 10, control device 100 controls the output of power from engine ENG by controlling the supply of fuel to engine ENG, the output of power from motor MOT by controlling the supply of electric power to motor MOT, the power generation (for example, output voltage) of generator GEN by controlling the field current flowing through the coil of generator GEN, and the like, for example.

When controlling the drive device 10, the control device 100 controls an actuator, not shown, that operates the first clutch CL1, to disengage or engage the first clutch CL 1. Similarly, the control device 100 controls an actuator, not shown, that operates the second clutch CL2 to disengage or engage the second clutch CL 2.

In this manner, control device 100 can cause vehicle 1 to travel in any one of a plurality of travel modes that can be adopted by vehicle 1 by controlling engine ENG, generator GEN, motor MOT, first clutch CL1, and second clutch CL 2. The control device 100 is an example of a vehicle control device according to the present invention, and is implemented by an Electronic Control Unit (ECU) having a processor, a memory, an interface, and the like, for example.

Travel patterns that vehicles can adopt

Next, a description will be given of a travel mode that can be adopted by the vehicle 1, with reference to a travel mode table Ta shown in fig. 2. As shown in fig. 2, the vehicle 1 can adopt a plurality of running modes including an EV running mode, a hybrid running mode, a low-speed-side engine running mode, and a high-speed-side engine running mode.

[ EV travel mode ]

The EV running mode is a running mode in which electric power is supplied from battery BAT to motor MOT and vehicle 1 is run by power output from motor MOT according to the electric power. In the EV running mode, engine ENG is stopped.

Specifically, in the EV running mode, the control device 100 disengages both the first clutch CL1 and the second clutch CL 2. In the EV running mode, control device 100 stops fuel injection to engine ENG (performs a so-called fuel cut), and stops output of power from engine ENG. In the EV running mode, control device 100 causes motor MOT to be supplied with electric power from battery BAT, and causes motor MOT to output power corresponding to the electric power (illustrated as motor "battery drive"). Thus, in the EV running mode, motor MOT outputs power from electric power supplied from battery BAT, and vehicle 1 runs with the output power.

In the EV running mode, as described above, the output of power from engine ENG is stopped, and both first clutch CL1 and second clutch CL2 are disengaged. Therefore, in the EV running mode, no power is input to the generator GEN, and no power generation by the generator GEN is performed (illustrated as "power generation stop" of the generator). Further, since the transition between the EV running mode and the hybrid running mode is not accompanied by a change in the state of the clutch, it can be easily and quickly performed. On the other hand, since the transition from the EV running mode to the engine running mode is a change of the clutch from the disconnected state to the connected state, accordingly, the transition takes time, and a temporary decrease in driving force sometimes occurs.

[ hybrid drive mode ]

The hybrid traveling mode is an example of the second traveling mode in the present invention, and is a traveling mode in which electric power is supplied from at least the generator GEN to the motor MOT and the vehicle 1 is caused to travel by the power output from the motor MOT according to the electric power.

Specifically, in the case of the hybrid drive mode, the control device 100 disengages both the first clutch CL1 and the second clutch CL 2. In the hybrid travel mode, control device 100 injects fuel into engine ENG so that power is output from engine ENG. The power output from the engine ENG is input to the generator GEN via the gear train Gg for the generator. Thereby, the generator GEN generates electric power.

In the hybrid travel mode, control device 100 supplies the electric power generated by generator GEN to motor MOT, and causes motor MOT to output a power corresponding to the electric power (illustrated as motor "generator drive"). The power supplied from generator GEN to motor MOT is larger than the power supplied from battery BAT to motor MOT. Therefore, in the hybrid travel mode, the power output from the motor MOT (the driving force of the motor MOT) can be increased as compared to the EV travel mode, and a large driving force can be obtained as the driving force of the vehicle 1.

In the case of the hybrid drive mode, control device 100 may supply electric power from battery BAT output by battery BAT to motor MOT as needed. That is, in the hybrid travel mode, control device 100 may supply electric power to motor MOT from both generator GEN and battery BAT. Thereby, the electric power supplied to the motor MOT can be increased as compared with the case where the electric power is supplied to the motor MOT only by the generator GEN. Therefore, the power output from the motor MOT can be increased, and a larger driving force can be obtained as the driving force of the vehicle 1.

[ Low-speed side Engine running mode ]

The low-speed-side engine running mode is an example of the first running mode in the present invention, and is a running mode in which the vehicle 1 runs by transmitting the power output from the engine ENG to the drive wheels DW through the low-speed-side power transmission path.

Specifically, in the low-speed-side engine running mode, control device 100 injects fuel into engine ENG so that power is output from engine ENG. In the low-speed-side engine running mode, the control device 100 engages the first clutch CL1 and disengages the second clutch CL 2. Thus, in the low-speed-side engine running mode, the power output from the engine ENG is transmitted to the drive wheels DW via the low-speed-side engine gear train GLo, the final gear train Gf, and the differential mechanism D, and the vehicle 1 runs.

In the low-speed-side engine running mode, the power output from engine ENG is also input to generator GEN via generator gear train Gg, but is controlled not to generate electric power by generator GEN. For example, in the low-speed-side engine running mode, the switching element provided in the power transmission path between generator GEN and battery BAT (for example, the switching element of the inverter device provided between generator GEN and battery BAT) is turned off, and the power generation of generator GEN is controlled not to be performed. Thus, in the low-speed-side engine running mode, the loss due to the power generation by the generator GEN can be reduced, and the amount of heat generated by the generator GEN and the like can be reduced. In the low-speed-side engine running mode, when the vehicle 1 is braked, regenerative power generation may be performed by the motor MOT using the motor MOT as a power generator, and the battery BAT may be charged with the generated power.

In the low-speed-side engine running mode, for example, control device 100 stops the supply of electric power to motor MOT and stops the output of power from motor MOT. Thus, in the low-speed-side engine running mode, the load on the motor MOT can be reduced, and the amount of heat generated by the motor MOT can be reduced.

In the case of the low-speed-side engine running mode, control device 100 may supply electric power from battery BAT to motor MOT as needed. Accordingly, even in the low-speed-side engine running mode, vehicle 1 can be run using the power output from motor MOT by the power supplied from battery BAT, and a larger driving force can be obtained as the driving force of vehicle 1 than in the case where vehicle 1 is run using only the power of engine ENG. In the present embodiment, it is also referred to as motor-assisted travel that the vehicle 1 travels using power output from the motor MOT based on the electric power supplied from the battery BAT, instead of the power of only the engine ENG.

[ high-speed side Engine running mode ]

The high-speed engine running mode is a running mode in which the power output from engine ENG is transmitted to drive wheels DW through a high-speed power transmission path to run vehicle 1.

Specifically, in the high-speed-side engine running mode, control device 100 injects fuel into engine ENG so that power is output from engine ENG. In the high-speed engine running mode, the control device 100 engages the second clutch CL2 and disengages the first clutch CL 1. Thus, in the high-speed-side engine running mode, the power output from engine ENG is transmitted to drive wheels DW via high-speed-side engine gear train GHi, final gear train Gf, and differential mechanism D, and vehicle 1 runs.

In the high-speed engine running mode, the power output from engine ENG is also input to generator GEN via generator gear train Gg, but is controlled not to generate electric power by generator GEN. Thus, in the high-speed-side engine running mode, the loss due to the power generation by the generator GEN can be reduced, and the amount of heat generated by the generator GEN and the like can be reduced. In the high-speed engine running mode, even when the vehicle 1 is braking, regenerative power generation may be performed by the motor MOT using the motor MOT as a power generator, and the battery BAT may be charged with the generated power.

In the high-speed engine running mode, control device 100 stops the supply of electric power to motor MOT, for example, and stops the output of power from motor MOT. Thus, in the high-speed engine running mode, the load on the motor MOT can be reduced, and the amount of heat generated by the motor MOT can be reduced.

In the case of the high-speed engine running mode, control device 100 may supply electric power from battery BAT to motor MOT as needed. Accordingly, even in the high-speed-side engine running mode, vehicle 1 can be run using the power output from motor MOT by the power supplied from battery BAT, and a larger driving force can be obtained as the driving force of vehicle 1 than in the case where vehicle 1 is run using only the power of engine ENG. In the high-speed-side engine running mode, running by motor assist is also referred to as running using not only the power of engine ENG but also the power output by motor MOT based on the electric power supplied from battery BAT.

In addition, in the transition from the hybrid travel mode to the engine travel mode, clutch CL changes from the disconnected state to the connected state. Therefore, when the hybrid drive mode is switched to the engine drive mode, predetermined control such as matching the rotation speed of engine ENG with the rotation speed of axle DS is necessary, and accordingly, time is required, and a temporary reduction in driving force may occur.

[ functional constitution of control device ]

Next, a functional configuration of the control device 100 will be described with reference to fig. 3 and 4. As shown in fig. 3, the control device 100 includes a vehicle information acquisition unit 110, a travel mode control unit 120 that controls a travel mode, and a drive device control unit 130 that controls the drive device 10. The vehicle information acquisition unit 110, the travel mode control unit 120, and the drive device control unit 130 can be realized by, for example, a processor of an ECU realizing the control device 100 executing a program stored in a memory or an interface of the ECU.

The vehicle information acquisition unit 110 acquires vehicle information (such as a running state and battery information) relating to the vehicle 1 based on detection signals transmitted from various sensors provided in the vehicle 1 to the control device 100. Vehicle information acquisition unit 110 transmits the acquired vehicle information to travel mode control unit 120 and drive device control unit 130. The vehicle information acquired by the vehicle information acquiring unit 110 includes information indicating a running state of the vehicle 1, such as a vehicle speed, an AP opening degree, and an engine speed, and battery information of the vehicle 1, such as a battery inter-terminal voltage, a battery charge/discharge current, and a battery temperature.

The battery information can be acquired based on a detection signal from a battery sensor S1 that detects the state of the battery BAT, for example. The battery sensor S1 detects the inter-terminal voltage, the charge/discharge current, the temperature, and the like of the battery BAT, and transmits detection signals indicating the detection signals to the control device 100.

The vehicle speed can be obtained based on a detection signal from a vehicle speed sensor S2 that detects the rotation speed of the axle DS, for example. The AP opening degree can be obtained based on a detection signal from an accelerator pedal position sensor (shown as an AP sensor) S3, and the accelerator pedal position sensor S2 detects an operation amount of an accelerator pedal provided in the vehicle 1. The required driving force can be obtained by deriving the required driving force based on the vehicle speed obtained based on the detection signal from the vehicle speed sensor S2 and the AP opening obtained based on the detection signal from the AP sensor S3.

Traveling mode control unit 120 sets any one of a plurality of traveling modes that vehicle 1 can adopt, and transmits a mode signal notifying the set traveling mode to drive device control unit 130. For example, information indicating the setting conditions of each traveling mode is stored in advance in control device 100. Here, the information indicating the setting condition of each running mode is, for example, information in which the running state of the vehicle 1 and a running mode suitable for the running state (that is, a running mode to be set) are associated with each other.

The travel pattern control unit 120 includes a detection unit 121, and the detection unit 121 can derive various information necessary for controlling the travel pattern based on the vehicle information acquired by the vehicle information acquisition unit 110. The detection unit 121 derives the required driving force required for the motor MOT, for example, based on the vehicle speed, the AP opening degree, and the like acquired by the vehicle information acquisition unit 110. Further, the detection unit 121 derives the required power required from the motor MOT for the battery BAT, based on, for example, the inter-terminal voltage and the output (discharge) current of the battery BAT acquired by the vehicle information acquisition unit 110.

The detection unit 121 derives the battery SOC based on, for example, the inter-terminal voltage of the battery BAT, the charge/discharge current, the discharge/charge time, the battery temperature, and the like acquired by the vehicle information acquisition unit 110. Further, based on the derived battery SOC, detection unit 121 derives the maximum output power that can be output by battery BAT. The detection unit 121 can derive the maximum output power based on the battery SOC by referring to a predetermined map indicating a relationship between the battery SOC and the maximum output power, for example. In addition, the battery temperature acquired by the vehicle information acquisition unit 110 may be further used when deriving the maximum output power.

In addition, the maximum driving force of vehicle 1 in the low-speed-side engine running mode is a power obtained by adding the power of engine ENG and the power output by motor MOT based on the electric power from battery BAT. Therefore, when the maximum output power of battery BAT is reduced, the output power of motor MOT is reduced, and the maximum driving force of vehicle 1 is reduced. Further, since the maximum output power of the battery BAT has a correlation with the battery SOC, when the battery SOC is lowered, the maximum output power of the battery BAT is also lowered.

For example, as shown in fig. 4, in the low-speed-side engine running mode, the maximum driving force that can be output by the vehicle 1 varies depending on the vehicle speed and the battery SOC. The SOC [% ] of the battery in fig. 4 is α > β > γ. When the vehicle speed is VP, the maximum driving force when SOC is α is N α, the maximum driving force when SOC is β is N β, the maximum driving force when SOC is γ is N γ, and N α > N β > N γ. That is, when battery SOC is decreased, the maximum output power of battery BAT is decreased, and the maximum driving force of vehicle 1 is also decreased by an amount corresponding to the decrease in the output power of motor MOT. Here, although an example of the low-speed-side engine running mode in which the above-described problem is likely to occur significantly is described, the same problem may occur in the high-speed-side engine running mode.

As shown in fig. 3, running mode control unit 120 includes a switching threshold value setting unit 122 for setting a switching threshold value that is a condition for switching the running mode. The switching threshold value setting unit 122 sets a switching threshold value for switching from the engine running mode to the hybrid running mode, for example, based on the derived maximum output power of the battery BAT. The conversion threshold value is stored in, for example, a conversion threshold value table (not shown) included in the travel mode control unit 120. The conversion threshold value is stored in advance in the conversion threshold value table in association with each maximum output power that can be output from battery BAT.

The switching threshold value in this case is a power value [ kW ] that is compared with the required power required from battery BAT by motor MOT in the engine running mode. Specifically, the switching threshold is a comparative power value as follows: even when the required power required from motor MOT for battery BAT increases, the travel mode is switched to the hybrid travel mode when the required power exceeds the switching threshold value, so that the required power can be appropriately (for example, without delay) supplied even when the travel mode is switched. The switching threshold is set to a value smaller than at least the maximum output power that can be output by battery BAT. Further, the switching threshold value is set to a relatively high value in the case where the maximum output power of the battery BAT is relatively large, and is set to a relatively low value in the case where the maximum output power of the battery BAT is relatively small.

The drive device control unit 130 controls the drive device 10 based on the travel mode set by the travel mode control unit 120, the vehicle information acquired by the vehicle information acquisition unit 110, and the like. For example, when receiving a mode signal for switching from the low-speed-side engine running mode to the hybrid running mode from running mode control unit 120, drive device control unit 130 disengages first clutch CL1, and inputs the power output from engine ENG to generator GEN to start the generation of power by generator GEN. Then, the electric power generated by the generator GEN is supplied to the motor MOT, so that the hybrid travel mode in which the vehicle 1 travels by the power output from the generator GEN by the motor MOT is switched.

[ control of Driving mode ]

Next, a process of control device 100 for switching the running mode of vehicle 1 will be described with reference to fig. 5.

As shown in fig. 5, first, the running mode control unit 120 of the control device 100 determines whether or not the current running mode of the vehicle 1 is the low-speed-side engine running mode (step S11).

If it is determined in step S11 that the running mode of the vehicle 1 is the low-speed-side engine running mode (yes in step S11), the running mode control unit 120 determines whether or not the low-speed-side engine running mode is under motor assist (step S12). As described above, the motor assist is a state in which the vehicle travels using not only the power of engine ENG but also the power output from motor MOT based on the electric power supplied from battery BAT.

On the other hand, if it is determined in step S11 that the running mode of vehicle 1 is not the low-speed-side engine running mode (no in step S11), running mode control unit 120 ends the present transition process.

Next, when it is determined in step S12 that the low-speed-side engine running mode is motor-assisted (yes in step S12), vehicle information acquisition unit 110 of control device 100 acquires battery information including a voltage between battery terminals, a battery charge/discharge current, a battery temperature, and the like from battery sensor S1 and acquires information indicating a running state of vehicle 1 including a vehicle speed, an AP opening degree, and the like from vehicle speed sensor S2 and AP sensor S3 (step S13).

On the other hand, if it is determined in step S12 that the low-speed-side engine running mode is not motor-assisted (no in step S12), running mode control unit 120 ends the present transition process.

Next, detection unit 121 of travel mode control unit 120 derives the required power that motor MOT requires for battery BAT based on the inter-terminal voltage and output (discharge) current of battery BAT acquired by vehicle information acquisition unit 110 in step S13 (step S14), and in the present process, the required power that motor MOT requires for battery BAT is hereinafter referred to as "output of battery" in the sense of the power that battery BAT actually outputs to motor MOT.

Next, detection unit 121 derives battery SOC based on the inter-terminal voltage of battery BAT, the discharge/charge time, and the battery temperature acquired by vehicle information acquisition unit 110 in step S13 (step S15).

Based on the battery temperature acquired in step S13 and the battery SOC derived in step S15, detector 121 derives the maximum output power that can be output by current battery BAT (step S16).

Next, switching threshold value setting unit 122 of running mode control unit 120 sets a switching threshold value for switching the engine running mode to the hybrid running mode, based on the maximum output power of battery BAT that can be output, which is derived in step S16 (step S17). The conversion threshold setting unit 122 sets a conversion threshold with reference to the conversion threshold table.

The running mode control unit 120 compares the output of the battery derived in step S14 with the switching threshold set in step S17, and determines whether or not the output of the battery is greater than the switching threshold (step S18).

If it is determined in step S18 that the output of the battery is greater than the switching threshold value (yes in step S18), running mode control unit 120 cancels the low-speed-side engine running mode and switches to the hybrid running mode (step S19).

On the other hand, when it is determined in step S18 that the output of the battery is equal to or less than the switching threshold (no in step S18), the running mode control unit 120 ends the present switching process.

The control of the running mode based on the above-described procedure is repeatedly executed at a predetermined cycle while the running mode of the vehicle 1 is set to the low-speed-side engine running mode. As a situation in which the control of the above-described process is executed, for example, a situation in which the vehicle 1 is traveling under a high load such as a situation in which the vehicle 1 climbs a slope while towing a trailer can be cited.

In this way, according to control device 100, the transition threshold value for the transition condition from the low-speed-side engine running mode to the hybrid running mode is changed in accordance with the maximum output power of battery BAT derived from battery SOC, and the running mode can be transitioned to the hybrid running mode based on the required power (output of the battery) requested for battery BAT from motor MOT and the transition threshold value. Thus, in a situation where there is a possibility that the driving force of vehicle 1 may be significantly reduced when the output of battery BAT is reduced, the running mode of vehicle 1 can be appropriately switched to the hybrid running mode.

However, in the low-speed-side engine running mode during motor assist in which the power of engine ENG and the power of motor MOT are added, since the SOC of battery BAT decreases when the power requested for motor MOT increases, the maximum output power of battery BAT decreases. For example, when the running mode is switched from the low-speed-side engine running mode to the hybrid running mode after the maximum output power of battery BAT is reduced, there is a case where "slowness" occurs in association with the reduction of the driving force at the time of the running mode switching. In order to prevent such a phenomenon, the switching threshold value that is a switching condition from the low-speed-side engine running mode to the hybrid running mode may be set as low as possible. On the other hand, from the viewpoint of fuel efficiency of the vehicle 1 and heat resistance performance due to heat generation of the generator GEN in the hybrid traveling mode, it is desirable to maintain traveling in the low-speed-side engine traveling mode for a long time. For this reason, the switching threshold value as the switching condition of the running mode may be set as high as possible.

In contrast, according to control device 100 of the present invention, the switching threshold value is changed according to the maximum output power of battery BAT derived based on battery SOC, and when the output of the battery exceeds the switching threshold value, the running mode can be switched to the hybrid running mode. This makes it possible to appropriately perform the switching from the low-speed-side engine running mode to the hybrid running mode without causing "slowness" in association with a decrease in driving force at the time of the running mode switching while suppressing a decrease in fuel efficiency and maintaining heat resistance performance.

Further, according to control device 100, in the low-speed-side engine running mode, when the output of the battery exceeds the switching threshold value, the switching is made to the hybrid running mode, whereby the acceleration force of vehicle 1 can be maintained. That is, the vehicle 1 can be accelerated by increasing the power of the motor MOT obtained based on the electric power of the generator GEN. The power output from the motor MOT depends on the electric power supplied from the generator GEN. Therefore, when the low-speed-side engine running mode is being adopted, the electric power requested from the battery BAT by the motor MOT is increased, and when the output of the battery exceeds the switching threshold value, the hybrid running mode is switched to, and the electric power generated by the generator GEN is supplied to the motor MOT, whereby the power output by the motor MOT can be increased, and the acceleration force of the vehicle 1 can be maintained.

Further, according to control device 100, when the maximum output power of battery BAT is relatively large, a relatively high value is set as the switching threshold, and when the maximum output power of battery BAT is relatively small, a relatively low value is set as the switching threshold. Therefore, it is possible to increase the chance of running vehicle 1 in the low-speed side engine running mode in a situation where sufficient output power can be obtained from battery BAT, which is preferable from the viewpoint of fuel efficiency and heat resistance performance.

While the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and modifications, improvements, and the like can be appropriately made.

For example, in the above-described embodiment, the example in which the switching threshold value to be the switching condition from the low-speed-side engine running mode to the hybrid running mode is changed based on the maximum output power of the battery BAT derived based on the battery SOC has been described, but the present invention is not limited to this. Similarly, the switching threshold value for the switching condition from the high-speed engine running mode to the hybrid running mode may be changed in accordance with the maximum output power of battery BAT derived based on battery SOC.

In the present specification, at least the following matters are described. In addition, although the corresponding components and the like in the above-described embodiments are shown in parentheses, the present invention is not limited to these.

(1) A control device (control device 100) of a vehicle that controls the vehicle, the vehicle being capable of traveling in a plurality of traveling modes including a first traveling mode (low-speed-side engine traveling mode) and a second traveling mode (hybrid traveling mode),

the first running mode is a running mode in which the drive wheels (drive wheels DW) of the vehicle (vehicle 1) can be driven by the power output from the internal combustion engine (engine ENG) and the power output from the electric motor (motor MOT) based on the electric power supplied from the power storage device (battery BAT),

the second running mode is a running mode in which the drive wheels can be driven by power output from the electric motor based on electric power supplied from a generator (generator GEN) that generates electric power from the power of the internal combustion engine,

wherein the vehicle control device includes a travel mode control unit (travel mode control unit 120) that causes the vehicle to travel in any travel mode of the plurality of travel modes,

the running mode control unit is capable of switching the running mode of the vehicle to the second running mode based on a detection result of a detection unit (detection unit 121) that detects an output of the power storage device and a predetermined switching threshold value when the first running mode is adopted as the running mode of the vehicle,

the travel mode control unit further includes a threshold setting unit (switching threshold setting unit 122) for setting the switching threshold,

the threshold setting unit changes the value of the conversion threshold according to a maximum output of the power storage device, which is derived based on an output of the power storage device.

According to (1), the switching threshold value that becomes the switching condition for switching from the first running mode to the second running mode can be changed according to the maximum output of the power storage device derived based on the output of the power storage device, and switching to the second running mode can be performed based on the detection result of the output of the power storage device and the switching threshold value. This enables the first travel mode to be switched to the second travel mode as appropriate.

(2) The control device of a vehicle according to (1), wherein,

the running mode control unit switches the running mode of the vehicle to the second running mode when the output of the power storage device exceeds the switching threshold set by the threshold setting unit when the first running mode is adopted as the running mode of the vehicle.

According to (2), when the first running mode is adopted, since the second running mode is switched when the output of the power storage device exceeds the switching threshold value, the acceleration force of the vehicle can be maintained. That is, the vehicle can be accelerated by increasing the power output by the motor. Further, the power output from the motor depends on the electric power supplied to the motor. Therefore, when the first running mode is adopted, the electric power requested from the electric storage device by the motor is increased, and when the output of the electric storage device exceeds the switching threshold value, the second running mode is switched to, and the electric power generated by the generator is supplied to the motor, whereby the power output by the motor can be increased to maintain the acceleration force of the vehicle.

(3) The control device of a vehicle according to (1) or (2), wherein,

the threshold setting unit sets a relatively high value as the conversion threshold when the maximum output of the power storage device is relatively large, and sets a relatively low value as the conversion threshold when the maximum output of the power storage device is relatively small.

According to (3), when the maximum output of the power storage device is relatively large, a relatively high value is set as the conversion threshold, and when the maximum output of the power storage device is relatively small, a relatively low value is set as the conversion threshold. This can increase the chance of the vehicle running in the first running mode in a situation where a sufficient output can be obtained from the power storage device.

(4) The control device of a vehicle according to any one of (1) to (3), wherein,

the running mode control unit switches the running mode of the vehicle to the second running mode based on the detection result of the detection unit and the switching threshold set by the threshold setting unit when the running mode of the vehicle is set to the first running mode and the vehicle is run by the power output from the internal combustion engine and the power output from the electric motor based on the electric power supplied from the power storage device.

According to (4), when the vehicle is caused to travel by using the first travel mode as the travel mode of the vehicle and by using the power output from the internal combustion engine and the power output from the electric motor based on the electric power supplied from the power storage device, the travel mode of the vehicle is switched to the second travel mode based on the detection result of the detection unit and the switching threshold value, so that the travel mode of the vehicle can be switched to the second travel mode in a situation where the driving force of the vehicle may be greatly reduced when the output of the power storage device is reduced.