Vehicle control device

Abstract

A vehicle control device that suppresses excessive transition from a first travel mode (in which an internal combustion engine is stopped and drive wheels are driven by an electric motor in accordance with power supplied from a power storage device) to a second travel mode (in which the internal combustion engine is operated and the drive wheels are driven by the electric motor in accordance with at least power supplied from a generator). The vehicle can travel in an EV travel mode (in which the engine is stopped and the drive wheels are driven by the first motor generator in accordance with power supplied from the battery) and a hybrid travel mode (in which the engine is operated and the drive wheels are driven by the first motor generator in accordance with at least power supplied from the second motor generator). A control device for a vehicle is provided with a processor that, when in an EV travel mode, performs a process that transitions from the EV travel mode to a hybrid travel mode on the basis of a state in which vehicle demand power exceeds a threshold value continues for a delay time; the delay time varies depending on the remaining amount of the battery.

Description

Technical Field

[0001] The invention relates to a vehicle control device. Background Art

[0002] In recent years, as a concrete countermeasure to global climate change, initiatives to achieve a low-carbon society or a decarbonized society have been active. 2 In order to reduce emissions and improve energy efficiency, research and development of electrification technology for electrifying the driving source is being carried out. Specifically, electric vehicles such as electric vehicles (Electrical Vehicles) and hybrid electric vehicles (Hybrid Electrical Vehicles) that use electric motors as driving sources are being developed.

[0003] Patent Document 1 discloses a technique in which, in a hybrid vehicle configured to switch from EV running to HV running when the SOC of a power storage device becomes equal to or less than a threshold, the threshold is increased when the required power during EV running is equal to or greater than the running power based on the maximum output of the engine.

[0004] Patent Document 2 listed below discloses a technique in which, in a hybrid vehicle, a transition is made from an HEV driving mode to an EV driving mode after a delay time set according to the deceleration of the vehicle has elapsed.

[0005] Patent Document 3 below discloses a technique in which, in a hybrid vehicle, when the output required power is greater than a predetermined engine delayed start power and less than a predetermined engine non-delay start power, the engine is started after a first set time has elapsed.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 6881210

[0009] Patent Document 2: Japanese Patent No. 5680279

[0010] Patent Document 3: Japanese Patent No. 6023480 Summary of the invention

[0011] Problems to be solved by the invention

[0012] However, in the prior art, excessively switching from the first driving mode (stopping the internal combustion engine and driving the drive wheels by the electric motor based on the power supply from the power storage device) to the second driving mode (operating the internal combustion engine and driving the drive wheels by the electric motor based on at least the power supply from the generator) may cause the vehicle's NV (Noise, Vibration) characteristics and fuel economy to deteriorate.

[0013] The present invention provides a vehicle control device that can suppress excessive transition from a first driving mode (stopping an internal combustion engine and driving a driving wheel by an electric motor according to power supply from a power storage device) to a second driving mode (operating an internal combustion engine and driving a driving wheel by an electric motor according to power supply from at least a generator), and further contributes to improvement of energy efficiency.

[0014] Means for solving problems

[0015] One aspect of the present invention is a vehicle control device for controlling a vehicle including an internal combustion engine, a generator driven by the internal combustion engine, a power storage device, and an electric motor driving a drive wheel based on power supply from at least one of the generator and the power storage device, wherein:

[0016] The vehicle is configured to be capable of traveling in any one of a plurality of travel modes, the plurality of travel modes including: a first travel mode in which the internal combustion engine is stopped and the vehicle travels by driving the drive wheels by the electric motor according to the power supply from the power storage device; and a second travel mode in which the internal combustion engine is operated and the vehicle travels by driving the drive wheels by the electric motor according to at least the power supply from the generator.

[0017] The vehicle control device includes a processor, and the processor performs the following processing:

[0018] When the vehicle is in the first driving mode, based on the fact that a state in which vehicle required power exceeds a threshold value continues for a predetermined delay time, shifting from the first driving mode to the second driving mode;

[0019] The delay time is made different according to the remaining amount of the power storage device.

[0020] Effects of the Invention

[0021] According to the present invention, a vehicle control device can be provided, which can suppress excessive transition from the first driving mode (stopping the internal combustion engine and driving the drive wheels by the electric motor according to the power supply from the power storage device) to the second driving mode (operating the internal combustion engine and driving the drive wheels by the electric motor according to at least the power supply from the generator). Moreover, it can contribute to the improvement of energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a diagram showing a schematic configuration of a vehicle 10 according to the present embodiment.

[0023] Figure 2 This is a flowchart showing an example of processing related to setting of the delay time, which is executed by the control device 20 that controls the vehicle 10 .

[0024] Figure 3 1 is a flowchart showing an example of processing related to transition from the EV driving mode to the hybrid driving mode, which is executed by the control device 20 that controls the vehicle 10 .

[0025] Figure 4 1 is a diagram showing a specific example of transition of the driving mode in the vehicle 10 .

[0026] Figure 5 This is a diagram showing an example of how the actual vehicle required power and the predicted vehicle required power increase when the required driving force increases.

[0027] Description of reference numerals:

[0028] 10 Vehicles

[0029] 20 Control device (vehicle control device)

[0030] 21 processors

[0031] BAT battery (power storage device)

[0032] ENG engine (internal combustion engine)

[0033] MG11st motor generator (motor)

[0034] MG2: second motor generator (generator). DETAILED DESCRIPTION

[0035] Hereinafter, an embodiment of the vehicle control device of the present invention is described in detail with reference to the accompanying drawings. In addition, not all of the features described in the following embodiments are necessary for the present invention. In addition, two or more of the multiple features described in the following embodiments may also be combined arbitrarily. Hereinafter, the same or similar elements are marked with the same or similar reference numerals, and their descriptions may be appropriately omitted or simplified.

[0036] [vehicle]

[0037] First, a vehicle including a control device (control device 20 described later) as one embodiment of the vehicle control device of the present invention will be described.

[0038] like Figure 1 As shown, the vehicle 10 of the present embodiment is a hybrid electric vehicle (Hybrid Electric Vehicle), which includes an engine ENG, a first motor generator MG1, a second motor generator MG2, a battery BAT, a clutch CL, a power conversion device 11, various sensors 12, and a control device 20. Figure 1 In the figure, the thick solid line represents the mechanical connection, the double-pointed line represents the electrical wiring, and the thin solid arrow represents the sending and receiving of the control signal or the detection signal.

[0039] The engine ENG is an internal combustion engine such as a gasoline engine or a diesel engine, and outputs power generated by burning the supplied fuel. The engine ENG is connected to the second motor generator MG2, and is also connected to the drive wheels DW of the vehicle 10 via the clutch CL. The power output by the engine ENG (hereinafter also referred to as "the output of the engine ENG") is transmitted to the second motor generator MG2 when the clutch CL is in the disconnected state, and is transmitted to the second motor generator MG2 and the drive wheels DW when the clutch CL is in the connected state (engaged state). The second motor generator MG2 and the clutch CL will be described later.

[0040] The first motor generator MG1 is an electric generator (so-called "traction motor") mainly used as a driving source of the vehicle 10, and is composed of, for example, an AC motor. The first motor generator MG1 is electrically connected to the battery BAT and the second motor generator MG2 via the power conversion device 11. The first motor generator MG1 can be supplied with electric power from at least one of the battery BAT and the second motor generator MG2. The first motor generator MG1 operates as a motor by supplying electric power, and outputs power for the vehicle 10 to travel. In addition, the first motor generator MG1 is connected to the drive wheel DW, and the power output by the first motor generator MG1 (hereinafter also referred to as "the output of the first motor generator MG1") is transmitted to the drive wheel DW. The vehicle 10 travels by transmitting at least one of the output of the aforementioned engine ENG and the output of the first motor generator MG1 to the drive wheel DW.

[0041] In addition, the first motor generator MG1 can also perform regenerative operation as a generator to generate electricity (so-called regenerative power generation) when the vehicle 10 is braked. The electric power generated by the regenerative operation of the first motor generator MG1 (hereinafter also referred to as "regenerative power") is supplied to the battery BAT via the power conversion device 11, for example. Thus, the battery BAT can be charged with the regenerative power.

[0042] In addition, the regenerative power is sometimes not supplied to the battery BAT but supplied to the second motor generator MG2 via the power conversion device 11. By supplying the regenerative power to the second motor generator MG2, "waste power" can be performed, that is, the regenerative power is consumed instead of charging the battery BAT. In addition, when the regenerative power is wasted, the regenerative power supplied to the second motor generator MG2 is used to drive the second motor generator MG2, and the power generated thereby is input to the engine ENG, and is consumed by mechanical friction loss of the engine ENG, etc.

[0043] The second motor generator MG2 is a motor generator mainly used as a generator, and is constituted by, for example, an AC motor. The second motor generator MG2 is driven by the power of the engine ENG to generate electricity. The electric power generated by the second motor generator MG2 is supplied to at least one of the battery BAT and the first motor generator MG1 via the power conversion device 11. By supplying the electric power generated by the second motor generator MG2 to the battery BAT, the battery BAT can be charged with the electric power. In addition, by supplying the electric power generated by the second motor generator MG2 to the first motor generator MG1, the first motor generator MG1 can be driven with the electric power.

[0044] Furthermore, the second motor generator MG2 can also function as a starter motor for starting the engine ENG. That is, for example, when the EV driving mode described later is switched to the hybrid driving mode, the power of the battery BAT is supplied to the second motor generator MG2, and the second motor generator MG2 is driven by the power to start the engine ENG, thereby starting the engine ENG.

[0045] The power conversion device 11 is a device that converts input power and outputs the converted power (so-called power control unit, also referred to as "PCU"), and is connected to the first motor generator MG1, the second motor generator MG2, and the battery BAT. For example, the power conversion device 11 is configured to include a first inverter 111, a second inverter 112, and a voltage control device 110. The first inverter 111, the second inverter 112, and the voltage control device 110 are electrically connected, respectively.

[0046] The voltage control device 110 converts the input voltage and outputs the converted voltage. As the voltage control device 110, a DC / DC converter or the like can be used. For example, when the power of the battery BAT is supplied to the first motor generator MG1, the voltage control device 110 steps up the output voltage of the battery BAT and outputs it to the first inverter 111. In addition, for example, when the first motor generator MG1 performs regenerative power generation, the voltage control device 110 steps down the output voltage of the first motor generator MG1 received via the first inverter 111 and outputs it to the battery BAT. In addition, when the second motor generator MG2 performs power generation, the voltage control device 110 steps down the output voltage of the second motor generator MG2 received via the second inverter 112 and outputs it to the battery BAT.

[0047] When the power of the battery BAT is supplied to the first motor generator MG1, the first inverter 111 converts the power (DC) of the battery BAT received via the voltage control device 110 into AC, and outputs it to the first motor generator MG1. In addition, when the first motor generator MG1 performs regenerative power generation, the first inverter 111 converts the power (AC) received from the first motor generator MG1 into DC, and outputs it to the voltage control device 110. In addition, when the regenerative power of the first motor generator MG1 is wasted, the first inverter 111 converts the power (AC) received from the first motor generator MG1 into DC, and outputs it to the second inverter 112.

[0048] When the second motor generator MG2 generates power, the second inverter 112 converts the power (AC) received from the second motor generator MG2 into DC, and outputs it to the voltage control device 110. In addition, when the regenerative power of the first motor generator MG1 is wasted, the second inverter 112 converts the regenerative power (DC) of the first motor generator MG1 received via the first inverter 111 into AC, and outputs it to the second motor generator MG2.

[0049] The battery BAT is a rechargeable and dischargeable secondary battery having a plurality of storage cells connected in series or in series-parallel. The battery BAT is configured to output a high voltage such as 100 to 400 [V]. As a single cell of the battery BAT, a lithium-ion battery, a nickel-metal hydride battery, etc. can be used.

[0050] The clutch CL can take: a connected state, in which the power transmission path from the engine ENG to the drive wheels DW is connected (engaged); and a disconnected state, in which the power transmission path from the engine ENG to the drive wheels DW is disconnected (disconnected). The output of the engine ENG is transmitted to the drive wheels DW when the clutch CL is in the connected state, and is not transmitted to the drive wheels DW when the clutch CL is in the disconnected state.

[0051] The various sensors 12 are sensors for acquiring various information related to the vehicle 10. Figure 1 As shown, the various sensors 12 include, for example, a vehicle speed sensor 12a for detecting the running speed (hereinafter also referred to as "vehicle speed") of the vehicle 10, an AP sensor 12b for detecting an AP opening (AP: Accelerator Position) indicating the amount of operation of the accelerator pedal by the vehicle 10, and a battery sensor 12c for detecting information related to the battery BAT (e.g., the output voltage, charge / discharge current, and temperature of the battery BAT). The detection results of the various sensors 12 are sent to the control device 20 as detection signals.

[0052] The control device 20 is a device (computer) that performs overall control of the vehicle 10, and is implemented by, for example, an ECU (Electronic Control Unit) having a processor 21 that performs various operations, a memory 22 that stores various information, and an I / F 23 (I / F: Interface) 23 that controls the input and output of internal and external data of the control device 20. The control device 20 may be implemented by one ECU or by a plurality of ECUs.

[0053] The control device 20 is provided so as to be able to communicate with the engine ENG, the clutch CL, the power conversion device 11, and various sensors 12. Furthermore, the control device 20 controls the output of the engine ENG by executing a program stored in the memory 22 through the processor 21, controls the output of the first motor generator MG1 and the second motor generator MG2 by controlling the power conversion device 11, or controls the state of the clutch CL. Thus, the control device 20 can control the driving mode of the vehicle 10 as described later.

[0054] For example, when the vehicle 10 is traveling, the control device 20 derives a required driving force as a target value of the driving force of the vehicle 10 (in other words, the driving force required for the vehicle 10 to travel) based on the vehicle speed detected by the vehicle speed sensor 12a and the AP opening detected by the AP sensor 12b. Furthermore, the control device 20 controls the output of the engine ENG and / or the first motor generator MG1 so that the driving force of the vehicle 10 becomes the required driving force, or controls the travel mode of the vehicle 10. In addition, the higher the vehicle speed, the greater the required driving force derived by the control device 20; and the greater the AP opening, the greater the required driving force derived by the control device 20.

[0055] [Driving mode of the vehicle]

[0056] Here, the driving modes that the vehicle 10 can adopt are described. The vehicle 10 can adopt driving modes such as EV driving mode, hybrid driving mode, and engine driving mode. Moreover, the vehicle 10 travels in any of these multiple driving modes. As described above, the control device 20 controls which driving mode the vehicle 10 travels in.

[0057] [EV driving mode]

[0058] The EV driving mode is an example of the first driving mode in the present invention, and only the electric power of the battery BAT is supplied to the first motor generator MG1, and the vehicle 10 is driven by the power output by the first motor generator MG1 based on the electric power. In the EV driving mode, the vehicle 10 drives the driving wheels DW only by the first motor generator MG1 of the engine ENG and the first motor generator MG1.

[0059] Specifically, in the case of the EV driving mode, the control device 20 puts the clutch CL into a disconnected state. In addition, in the case of the EV driving mode, the control device 20 stops supplying fuel to the engine ENG, thereby stopping the power output from the engine ENG (hereinafter also referred to as "operation of the engine ENG"). Therefore, in the EV driving mode, the second motor generator MG2 does not generate electricity. Moreover, in the case of the EV driving mode, the control device 20 only supplies the power of the battery BAT to the first motor generator MG1, so that the power corresponding to the power is output from the first motor generator MG1, and the vehicle 10 is driven by the power.

[0060] The control device 20 basically causes the vehicle 10 to travel in the EV travel mode under the condition that the power required by the vehicle 10 (hereinafter also referred to as "vehicle required power") is less than a predetermined threshold value (hereinafter also referred to as "EV allowed power"). The vehicle required power in the EV travel mode includes the power required to travel the vehicle 10 by the first motor generator MG1, and changes according to the required driving force and the vehicle speed.

[0061] [Hybrid driving mode]

[0062] The hybrid driving mode is an example of the second driving mode in the present invention, and at least the electric power generated by the second motor generator MG2 is supplied to the first motor generator MG1, and the vehicle 10 is driven mainly by the power output by the first motor generator MG1 based on the electric power. In the hybrid driving mode, the vehicle 10 drives the driving wheels DW only by the first motor generator MG1 of the engine ENG and the first motor generator MG1.

[0063] Specifically, in the case of the hybrid driving mode, the control device 20 puts the clutch CL into a disconnected state. In addition, in the case of the hybrid driving mode, the control device 20 supplies fuel to the engine ENG, thereby outputting power from the engine ENG, and driving the second motor generator MG2 with the power of the engine ENG. As a result, in the hybrid driving mode, the second motor generator MG2 generates power. In addition, in the case of the hybrid driving mode, the control device 20 puts the power transmission path into a disconnected state through the clutch CL, and supplies the power generated by the second motor generator MG2 to the first motor generator MG1, so that the power corresponding to the power is output from the first motor generator MG1, and the vehicle 10 is driven by the power.

[0064] The power supplied from the second motor generator MG2 to the first motor generator MG1 is greater than the power supplied from the battery BAT to the first motor generator MG1. Therefore, in the hybrid travel mode, the output of the first motor generator MG1 can be increased compared to the EV travel mode, and a larger driving force can be obtained.

[0065] In addition, in the case of the hybrid driving mode, the control device 20 can also supply the power of the battery BAT to the first motor generator MG1 as needed. That is, in the hybrid driving mode, the control device 20 can supply the power of both the second motor generator MG2 and the battery BAT to the first motor generator MG1. Thereby, compared with the case where only the power of the second motor generator MG2 is supplied to the first motor generator MG1, the power supplied to the first motor generator MG1 can be increased, and a greater driving force can be obtained.

[0066] [Engine driving mode]

[0067] In the engine travel mode, the vehicle 10 is mainly caused to travel by the power output by the engine ENG, and travels at least by driving the drive wheels DW by the engine ENG.

[0068] Specifically, in the case of the engine travel mode, the control device 20 connects the clutch CL. In addition, in the case of the engine travel mode, the control device 20 supplies fuel to the engine ENG and outputs power from the engine ENG. In the case of the engine travel mode, since the power transmission path is connected by the clutch CL, the power of the engine ENG is transmitted to the drive wheel DW, thereby driving the drive wheel DW. In this way, in the case of the engine travel mode, the control device 20 outputs power from the engine ENG and uses the power to drive the vehicle 10.

[0069] In the case of the engine running mode, the control device 20 can supply the power of the battery BAT to the first motor generator MG1 as needed. Therefore, in the engine running mode, the power output by the first motor generator MG1 by supplying the power of the battery BAT can also be used to run the vehicle 10, and a larger driving force can be obtained compared to the case where the vehicle 10 is run only by the power of the engine ENG. In addition, compared to the case where the vehicle 10 is run only by the power of the engine ENG, the output of the engine ENG can be suppressed, and the fuel economy of the vehicle 10 can be improved.

[0070] [Control by the Control Device of the Present Embodiment]

[0071] Next, the control performed by the control device 20 will be described in more detail.

[0072] The vehicle power requirement in EV driving mode changes all the time, and sometimes exceeds the EV allowed power momentarily. If the EV driving mode is switched to the hybrid driving mode even when the vehicle power requirement exceeds the EV allowed power momentarily, the switch from EV driving mode to hybrid driving mode may occur at a high frequency. The switch from EV driving mode to hybrid driving mode is accompanied by the start of the engine ENG, so if such a switch occurs at a high frequency, it will lead to deterioration of the NV (Noise, Vibration) characteristics and fuel economy of the vehicle 10. Therefore, it is desirable to suppress excessive switch from EV driving mode to hybrid driving mode.

[0073] Therefore, in the present embodiment, when the vehicle 10 is in the EV driving mode, the EV driving mode is shifted to the hybrid driving mode based on the fact that the state where the vehicle required power exceeds the EV allowed power (i.e., a predetermined threshold value) continues for a predetermined delay time. And, the delay time is made different depending on the remaining amount of the battery BAT (hereinafter also referred to as "SOC (State Of Charge)").

[0074] Therefore, according to the present embodiment, it is possible to suppress the situation where the vehicle 10 is shifted from the EV driving mode to the hybrid driving mode only because the state where the vehicle required power exceeds the EV allowed power continues for a while despite the sufficient SOC. As a result, it is possible to suppress the excessive shift from the EV driving mode to the hybrid driving mode, and it is possible to prevent the NV characteristics and fuel economy of the vehicle 10 from being deteriorated due to such a shift. In addition, according to the present embodiment, it is also possible to quickly shift from the EV driving mode to the hybrid driving mode when the SOC is insufficient, and to prevent the SOC from being excessively reduced.

[0075] Below, refer to Figure 2 as well as Figure 3 , an example of the processing performed by the control device 20 when the vehicle 10 is in the EV driving mode is described. This processing is performed, for example, by the processor 21 of the control device 20 executing a program pre-stored in the memory 22. In addition, Figure 2 The series of processing shown and Figure 3 The series of processes shown are repeatedly executed at a predetermined cycle (for example, every 5 [ms]) when the running mode of the vehicle 10 is the EV running mode, for example.

[0076] like Figure 2 As shown, the control device 20 first derives the vehicle required power (step S1). The vehicle required power in the EV driving mode can be derived based on, for example, a TRC torque requirement value (TRC: traction) as a target value of the torque generated by the first motor generator MG1 and a TRC speed as the speed of the first motor generator MG1. Here, the TRC torque requirement value can be obtained, for example, based on the required driving force. In addition, the TRC speed can be obtained, for example, based on the vehicle speed detected by the vehicle speed sensor 12a. The larger the TRC torque requirement value and the TRC speed, in other words, the larger the required driving force and the vehicle speed, the larger the vehicle required power.

[0077] The control device 20 may also derive the vehicle required power by taking into account not only the first motor generator MG1 but also the power consumption of auxiliary devices (for example, an air conditioner, a cooling device, etc.) included in the vehicle 10 .

[0078] For example, in this case, the various sensors 12 are configured to include a sensor for detecting the power consumption of the auxiliary machine provided in the vehicle 10, and the control device 20 obtains the power consumption of the auxiliary machine based on the detection result of the sensor. Moreover, when the vehicle 10 is in the EV driving mode, the control device 20 derives the sum of the power required for the vehicle 10 to travel by the first motor generator MG1 and the obtained power consumption of the auxiliary machine as the vehicle required power. In this way, a more accurate vehicle required power can be derived for the power actually required in the vehicle 10, and the vehicle required power can be used more appropriately for various processes. In addition, the control device 20 can also obtain the power consumption of the auxiliary machine by estimating the power consumption of the auxiliary machine based on the operating state of the auxiliary machine, etc.

[0079] Next, the control device 20 derives the difference between the vehicle required power and the EV allowed power, i.e., ΔEV allowed power, based on the vehicle required power derived by the process of step S1 and the preset EV allowed power (step S2). In the process of step S2, the control device 20 derives the value obtained by subtracting the EV allowed power from the vehicle required power as ΔEV allowed power, for example.

[0080] Next, the control device 20 derives the delay time corresponding to the combination of the ΔEV allowed power and the SOC based on the ΔEV allowed power derived by the process of step S2 and the current SOC (i.e., the remaining amount of the battery BAT) (step S3). In the process of step S3, the control device 20 derives the delay time corresponding to the above-mentioned combination of the ΔEV allowed power and the SOC by using, for example, a table (information) that defines the delay time for each combination of the ΔEV allowed power and the SOC or a predetermined calculation formula.

[0081] For example, Figure 2 As shown in the comment box of the symbol α in , the delay time derived by the process of step S3 is designed to be shorter as the ΔEV allowable power is larger, and longer as the SOC is larger. That is, the control device 20 shortens the delay time as the ΔEV allowable power is larger, and lengthens the delay time as the SOC is larger.

[0082] The delay time is shortened as the ΔEV allowed power is larger. For example, when the required driving force is large and the vehicle requires a large power, the EV driving mode can be quickly transferred to the hybrid driving mode. This can prevent the EV driving mode that cannot ensure the required driving force from continuing for a long time and causing the drivability of the vehicle 10 to deteriorate. In addition, the delay time is extended as the SOC increases. As described above, it is possible to prevent the NV characteristics and fuel economy of the vehicle 10 from being excessively transferred from the EV driving mode to the hybrid driving mode. In addition, the SOC can be obtained, for example, based on the detection result of the battery sensor 12c.

[0083] Next, the control device 20 sets the delay time derived by the process of step S3 as one of the conditions for whether to shift from the EV driving mode to the hybrid driving mode (step S4), and ends. Figure 2 A series of processing shown.

[0084] In addition, if Figure 3 As shown, the control device 20 determines whether the delay flag is on (step S11). The delay flag is set to on when the vehicle required power exceeds the EV allowed power, and the details will be described later.

[0085] If it is determined that the delay flag is off (step S11: No), the control device 20 determines whether the vehicle required power derived by the most recent step S1 is greater than the EV allowed power (step S12). If it is determined that the vehicle required power is not greater than the EV allowed power (step S12: No), the control device 20 directly ends the operation. Figure 3 A series of processing shown.

[0086] When it is determined that the vehicle required power is greater than the EV allowed power (step S12 : YES), the control device 20 starts measuring the elapsed time (step S13 ), and sets the delay flag to on (step S14 ).

[0087] Next, the control device 20 determines whether the elapsed time measured by the process of step S13 is greater than the delay time set by the most recent process of step S4 (step S15). If it is determined that the elapsed time is not greater than the delay time (step S15: No), the control device 20 directly ends the process. Figure 3 A series of processing shown.

[0088] If it is determined that the elapsed time is longer than the delay time (step S15: Yes), the control device 20 sets the delay flag to off (step S16), and resets the elapsed time measured by the process of step S13 to "0" (step S17). Then, the control device 20 switches the driving mode of the vehicle 10 from the EV driving mode to the hybrid driving mode (step S18), and ends. Figure 3 A series of processing shown.

[0089] In addition, in the process of step S11, when it is determined that the delay flag is on (step S11: Yes), the control device 20 determines whether the vehicle required power is greater than the EV allowed power (step S19) in the same way as the process of step S12 described above. When it is determined that the vehicle required power is greater than the EV allowed power (step S19: Yes), the control device 20 proceeds to the process of step S15 described above.

[0090] When it is determined that the required vehicle power is not greater than the allowable EV power (step S19: No), the control device 20 sets the delay flag to OFF (step S20), and resets the elapsed time of the measurement started by the process of step S13 to "0" (step S21), and ends Figure 3 The series of processes shown.

[0091] [Example of transfer of specific driving modes in the vehicle of the present embodiment]

[0092] Next, with reference to Figure 4 , an example of transfer of specific driving modes in the vehicle 10 will be described. In Figure 4 (a), the vertical axis represents the required vehicle power, and the horizontal axis represents the time period. In Figure 4 (b), the vertical axis represents the SOC, and the horizontal axis represents the time period. Figure 4 (c) shows the driving mode of the vehicle 10 at each time period.

[0093] In Figure 4 the example shown, the periods Ta from time t1 to time t2, the period Tb from time t4 to time t5, and the period T from time t7 to time t9 c are respectively the periods when the required vehicle power is greater than the allowable EV power.

[0094] In addition, at time t1, the SOC is "x" (where x > 0), and the control device 20 sets a delay time of "Dx" (where Dx > 0) according to this SOC of "x". Similarly, at time t4, the SOC is "y" (where 0 < y < x), and the control device 20 sets a delay time of "Dy" (where 0 < Dy < Dx) according to this SOC of "y". And at time t7, the SOC is "z" (where 0 < z < y), and the control device 20 sets a delay time of "Dz" (where 0 < Dz < Dy) according to this SOC of "z".

[0095] In the case of this example, the time t2 when the required vehicle power becomes less than or equal to the allowable EV power immediately after time t1 is earlier than the time t3 after "Dx" time has elapsed from time t1. Therefore, during the period from time t1 to time t2, although the required vehicle power exceeds the allowable EV power, the control device 20 does not transfer to the hybrid driving mode but maintains the EV driving mode.

[0096] Similarly, the time t5 when the required vehicle power becomes less than or equal to the allowable EV power immediately after time t4 is earlier than the time t6 after "Dy" time has elapsed from time t4. Therefore, during the period from time t4 to time t5, although the required vehicle power exceeds the allowable EV power, the control device 20 does not transfer to the hybrid driving mode but maintains the EV driving mode.

[0097] On the other hand, the period t9 at which the vehicle required power becomes less than the EV permitted power immediately after the period t7 is later than the period t8 at which the time "Dz" has passed since the period t7. In other words, here, even if the delay time "Dz" has passed since the period t7 at which the vehicle required power exceeds the EV permitted power, the vehicle required power continues to exceed the EV permitted power. Therefore, in this case, the control device 20 shifts from the EV driving mode to the hybrid driving mode. Specifically, the control device 20 sets the vehicle 10 to the hybrid driving mode, for example, during the period t8 at which the delay time "Dz" has passed since the period t7 at which the vehicle required power exceeds the EV permitted power until the period t9 at which the vehicle required power becomes less than the EV permitted power.

[0098] As described above, when the vehicle 10 is in the EV driving mode, the control device 20 shifts from the EV driving mode to the hybrid driving mode based on the fact that the state in which the vehicle required power exceeds the EV allowed power continues for a delay time corresponding to the SOC. Thus, it is possible to appropriately shift from the EV driving mode to the hybrid driving mode in consideration of the SOC, and it is possible to prevent the NV characteristics and fuel economy of the vehicle 10 from being deteriorated due to excessive shifting from the EV driving mode to the hybrid driving mode. Furthermore, it is possible to contribute to the improvement of energy efficiency.

[0099] However, there are also cases where the vehicle's required power exceeds the EV's permitted power (e.g. Figure 4 Compared with the period t7 in the Figure 4 During period t8), the vehicle speed increases and the electric power required by the vehicle also increases.

[0100] In addition, in the vehicle 10, when the EV driving mode is shifted to the hybrid driving mode, the power of the battery BAT is supplied to the second motor generator MG2, and the engine ENG is cranked by the second motor generator MG2, thereby starting the engine ENG. Therefore, when the EV driving mode is shifted to the hybrid driving mode, the power is also supplied to the second motor generator MG2, and the power output from the battery BAT increases accordingly.

[0101] As described above, when the EV driving mode is switched to the hybrid driving mode after the period when the vehicle required power exceeds the EV allowed power, the power output from the battery BAT is excessive at the time of the switch, and the power consumption caused by the internal resistance of the battery BAT, that is, the battery loss, may also increase accordingly. From the viewpoint of suppressing the increase of such battery loss, the switch from the EV driving mode to the hybrid driving mode is preferably performed before the vehicle required power becomes excessive.

[0102] Therefore, the control device 20 may predict the vehicle speed a predetermined time from now assuming that the required driving force is generated based on the required driving force and the weight of the vehicle 10, and derive the vehicle required power using the predicted vehicle speed (hereinafter also referred to as "predicted vehicle speed").

[0103] Here, the specified time (e.g. Figure 5 The specified time T) shown is, for example, less than the minimum delay time Dmin that can be derived as the processing result of step S3, and is pre-set by the manufacturer of the vehicle 10. Thus, the vehicle speed suitable for use in the process related to the transition from the EV driving mode to the hybrid driving mode can be predicted as the predicted vehicle speed.

[0104] Specifically, in this case, the control device 20 uses the predicted vehicle speed instead of the vehicle speed detected by the aforementioned vehicle speed sensor 12a (hereinafter also referred to as the "actual vehicle speed") to obtain the TRC speed, and uses the TRC speed to derive the vehicle required power. In addition, the predicted vehicle speed can be obtained by solving the motion equation for the vehicle 10, for example. In addition, hereinafter, the vehicle required power derived using the actual vehicle speed is also referred to as the "actual vehicle required power", and the vehicle required power derived using the predicted vehicle speed instead of the actual vehicle speed is referred to as the "predicted vehicle required power".

[0105] Here, refer to Figure 5 , an example of how the actual vehicle power requirement and the predicted vehicle power requirement increase when the required driving force increases is described. Figure 5 In (a), the vertical axis represents the required driving force and the horizontal axis represents the period. Figure 5 In (b), the vertical axis represents the actual vehicle speed and the predicted vehicle speed, and the horizontal axis represents the time period. Figure 5 In (c) , the vertical axis represents the actual vehicle required power and the predicted vehicle required power, and the horizontal axis represents the time period.

[0106] exist Figure 5 In the example shown, at time t11, the driver of the vehicle 10 steps on the accelerator pedal, and the required driving force increases according to this operation. Usually, even if the required driving force increases, as shown in FIG. Figure 5 As shown, a time lag occurs even before the vehicle 10 accelerates (in other words, the actual vehicle speed increases). Therefore, the increase in the actual vehicle required power based on the actual vehicle speed is also delayed relative to the time t11 when the required driving force increases.

[0107] In contrast, Figure 5 As shown, the predicted vehicle speed increases earlier than the actual vehicle speed by a predetermined time T. Therefore, the predicted vehicle required power based on the predicted vehicle speed also increases earlier than the actual vehicle required power by a predetermined time T.

[0108] For example, the predicted vehicle speed at time t12 immediately after time t11 is substantially the same as the actual vehicle speed at time t13 after a predetermined time T has elapsed from time t12 , and the predicted vehicle required power at time t12 is substantially the same as the actual vehicle required power at time t13 .

[0109] Therefore, by using such predicted vehicle required power, processing related to the transition from the EV driving mode to the hybrid driving mode is performed, such as Figure 5 As shown by the hollow arrow with the reference β in FIG. 1 , the transition from the EV driving mode to the hybrid driving mode, i.e., the starting of the engine ENG, can be accelerated. As a result, compared with the case where the actual vehicle required power is used to perform the processing related to the transition from the EV driving mode to the hybrid driving mode, the power output from the battery BAT when the EV driving mode is transitioned to the hybrid driving mode can be reduced, and the battery loss during the transition can be suppressed.

[0110] Above, an embodiment of the present invention has been described, but the present invention is certainly not limited to this embodiment. Obviously, those skilled in the art can think of various variations or modifications within the scope of the technical solution, and it should be understood that these variations and modifications also belong to the technical scope of the present invention.

[0111] In addition, the control method described in the present embodiment can be implemented by executing a pre-prepared program (control program) by a computer. The control program is stored in a computer-readable storage medium (e.g., memory 22) and is executed by reading from the storage medium. In addition, the control program can be provided in the form of being stored in a non-volatile (non-temporary) storage medium such as a flash memory, or can be provided via a network such as the Internet.

[0112] In addition, in the present embodiment, the computer executing the control program is used as the control device 20, and the control method described above is implemented by executing the control program by the processor 21 of the control device 20, but the present invention is not limited thereto. The computer executing the control program is not limited to being included in the vehicle 10, and may be included in a server device capable of communicating with the vehicle 10 (control device 20), for example.

[0113] At least the following matters are described in this specification, etc. In parentheses, corresponding components in the above-mentioned embodiment are shown as examples, but the present invention is not limited to these.

[0114] (1) A vehicle control device (control device 20) for controlling a vehicle (vehicle 10) including an internal combustion engine (engine ENG), a generator (second motor generator MG2) driven by the internal combustion engine, a power storage device (battery BAT), and an electric motor (first motor generator MG1) driving driving wheels based on power supplied from at least one of the generator and the power storage device, wherein:

[0115] The vehicle is configured to be capable of traveling in any one of a plurality of travel modes, the plurality of travel modes including: a first travel mode in which the internal combustion engine is stopped and the vehicle travels by driving the drive wheels by the electric motor according to the power supply from the power storage device; and a second travel mode in which the internal combustion engine is operated and the vehicle travels by driving the drive wheels by the electric motor according to at least the power supply from the generator.

[0116] The vehicle control device includes a processor (processor 21) which performs the following processing:

[0117] When the vehicle is in the first driving mode, based on the fact that a state in which vehicle required power exceeds a threshold value continues for a predetermined delay time, shifting from the first driving mode to the second driving mode;

[0118] The delay time is made different according to the remaining amount of the power storage device.

[0119] According to (1), it is possible to suppress a situation in which the vehicle is shifted from the first driving mode to the second driving mode simply because the state in which the vehicle's required power exceeds the threshold value continues for a short period of time despite the sufficient remaining amount of the power storage device. As a result, it is possible to suppress an excessive shift from the first driving mode to the second driving mode, and it is possible to prevent the NV (Noise, Vibration) characteristics of the vehicle and the fuel economy from being deteriorated due to such a shift. In addition, according to (1), it is also possible to quickly shift from the first driving mode to the second driving mode when the remaining amount of the power storage device is insufficient, and to prevent the remaining amount of the power storage device from being excessively reduced.

[0120] (2) The vehicle control device according to (1), wherein:

[0121] The processor extends the delay time as the remaining amount of the power storage device increases.

[0122] According to (2), it is possible to prevent the NV characteristics and fuel economy of the vehicle from being deteriorated due to excessive shift from the first running mode to the second running mode.

[0123] (3) The vehicle control device according to (2), wherein:

[0124] The greater the required driving force of the vehicle, the greater the required electric power of the vehicle.

[0125] The processor further performs processing such that the delay time is shortened as the difference between the vehicle required power and the threshold value is larger.

[0126] According to (3), when the required driving force is large and the vehicle requires a large amount of electric power, the first driving mode can be quickly switched to the second driving mode. This can prevent the first driving mode, which cannot ensure the required driving force, from continuing for a long time and causing the vehicle's drivability to deteriorate.

[0127] (4) The vehicle control device according to any one of (1) to (3), wherein:

[0128] When the vehicle is in the first running mode, the processor derives the vehicle required power as a sum of power required for running the vehicle by the electric motor and power consumption of an auxiliary device included in the vehicle.

[0129] According to (4), it is possible to derive more accurate vehicle required power from the power actually required in the vehicle, and to perform various processes more appropriately using the vehicle required power.

[0130] (5) The vehicle control device according to any one of (1) to (3), wherein:

[0131] The processor predicts a running speed of the vehicle a predetermined time later assuming that the required driving force is generated, based on a required driving force of the vehicle and a weight of the vehicle, and derives the vehicle required power using the predicted running speed.

[0132] According to (5), compared with the case where the actual vehicle speed is used to derive the vehicle required power and the vehicle required power is used to perform processing related to the transition from the first driving mode to the second driving mode, the time for transition from the first driving mode to the second driving mode can be advanced, the power output from the power storage device during the transition can be reduced, and the loss caused by the internal resistance of the power storage device during the transition can be suppressed.

[0133] (6) The vehicle control device according to (5), wherein:

[0134] The predetermined time is a time equal to or shorter than the delay time.

[0135] According to (6), it is possible to predict a traveling speed suitable for use in a process related to transition from the first traveling mode to the second traveling mode.

Claims

1. A vehicle control device for controlling a vehicle, the vehicle comprising an internal combustion engine, a generator driven by the internal combustion engine, a power storage device, and an electric motor driving a drive wheel based on power supply from at least one of the generator and the power storage device, wherein: The vehicle is configured to be capable of traveling in any one of a plurality of travel modes, the plurality of travel modes including: a first travel mode in which the internal combustion engine is stopped and the vehicle travels by driving the drive wheels by the electric motor according to the power supply from the power storage device; and a second travel mode in which the internal combustion engine is operated and the vehicle travels by driving the drive wheels by the electric motor according to at least the power supply from the generator. The vehicle control device includes a processor, and the processor performs the following processing: When the vehicle is in the first driving mode, based on the fact that a state in which vehicle required power exceeds a threshold value continues for a predetermined delay time, shifting from the first driving mode to the second driving mode; The delay time is made different according to the remaining amount of the power storage device.

2. The vehicle control device according to claim 1, wherein: The processor extends the delay time as the remaining amount of the power storage device increases.

3. The vehicle control device according to claim 2, wherein: The greater the required driving force of the vehicle, the greater the required electric power of the vehicle. The processor further performs processing such that the delay time is shortened as the difference between the vehicle required power and the threshold value is larger.

4. The vehicle control device according to any one of claims 1 to 3, wherein: When the vehicle is in the first running mode, the processor derives the vehicle required power as a sum of power required for running the vehicle by the electric motor and power consumption of an auxiliary device included in the vehicle.

5. The vehicle control device according to any one of claims 1 to 3, wherein: The processor predicts a running speed of the vehicle a predetermined time later assuming that the required driving force is generated, based on a required driving force of the vehicle and a weight of the vehicle, and derives the vehicle required power using the predicted running speed.

6. The vehicle control device according to claim 5, wherein: The predetermined time is a time equal to or shorter than the delay time.

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