Vehicle controller

Abstract

To inhibit a transition from a first travel mode in which an internal combustion engine is halted and an electric motor drives drive wheels according to supply of electric power from a power storage apparatus, to a second travel mode in which the internal combustion engine is activated and the electric motor drives the drive wheels according to supply of electric power from a power generator, from being excessively made.SOLUTION: A vehicle 10 can travel in an EV travel mode in which an engine ENG is halted and a first motor generator MG1 drives drive wheels DW according to supply of electric power from a battery BAT, and in a hybrid travel mode in which the engine ENG is activated and the first motor generator MG1 drives the drive wheels DW according to supply of electric power from a second motor generator MG2. A controller 20 of the vehicle includes a processor 21 that, in the EV travel mode, makes a transition from the EV travel mode to the hybrid travel mode on the basis of a fact that a condition where a vehicle request electric power exceeds a threshold continues over a delay time, and that varies the delay time according to a battery capacity of the battery BAT.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have been gaining momentum as a concrete measure against global climate change. Reductions in CO2 emissions and improvements in energy efficiency are also required for automobiles and other vehicles, and research and development is being conducted on electrification technologies to electrify their drive sources. Specifically, development is underway for electric vehicles and hybrid electric vehicles, which use electric motors as their drive source.

[0003] The following Patent Document 1 discloses a technology for a hybrid vehicle configured to switch from EV driving to HV driving when the SOC of the power storage device falls below a threshold, in which the threshold is increased when the required power during EV driving is equal to or greater than the driving power based on the maximum output of the engine.

[0004] The following Patent Document 2 discloses a technique for transitioning a hybrid vehicle 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] The following Patent Document 3 discloses a technology 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-delayed start power, the engine is started after a first set time has elapsed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6881210 [Patent Document 2] Patent No. 5680279 [Patent Document 3] Patent No. 6023480 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the prior art, there was a risk of the vehicle's NV (Noise, Vibration) characteristics and fuel economy deteriorating due to excessive transitions from a first driving mode, in which the internal combustion engine is stopped and the electric motor drives the drive wheels in response to power supplied from an energy storage device, to a second driving mode, in which the internal combustion engine is operated and the electric motor drives the drive wheels in response to power supplied at least from a generator.

[0008] The present invention provides a vehicle control device that can suppress excessive transition from a first driving mode in which the operation of the internal combustion engine is stopped and the electric motor drives the drive wheels in response to the power supply from the power storage device to a second driving mode in which the internal combustion engine is operated and the electric motor drives the drive wheels in response to the power supply from at least a generator, thereby contributing to improvement of energy efficiency. [Means for solving the problem]

[0009] One aspect of the present invention is A vehicle control device that controls a vehicle including an internal combustion engine, a generator driven by the internal combustion engine, a power storage device, and an electric motor that drives drive wheels in response to electric power supply from at least one of the generator and the power storage device, The vehicle is The vehicle is configured to be capable of traveling in any one of a plurality of traveling modes including a first traveling mode in which the operation of the internal combustion engine is stopped and the electric motor drives the drive wheels in response to the supply of electric power from the power storage device, and a second traveling mode in which the internal combustion engine is operated and the electric motor drives the drive wheels in response to at least the supply of electric power from the generator, The vehicle control device includes: transitioning the vehicle from the first traveling mode to the second traveling mode based on a state in which a vehicle required electric power required by the vehicle exceeds a threshold value for a predetermined delay time when the vehicle is in the first traveling mode; The delay time is varied depending on the remaining capacity of the power storage device. A processor for performing processing, A vehicle control device. Effect of the Invention

[0010] According to the present invention, it is possible to provide a vehicle control device that can suppress excessive transition from a first driving mode in which the operation of the internal combustion engine is stopped and the electric motor drives the drive wheels in response to the power supply from the power storage device to a second driving mode in which the internal combustion engine is operated and the electric motor drives the drive wheels in response to at least the power supply from the generator, thereby contributing to improvement of energy efficiency. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a vehicle 10 according to the present embodiment. [Diagram 2] FIG. 2 is a flowchart showing an example of a process for setting a delay time, which is executed by the control device 20 that controls the vehicle 10. As shown in FIG. [Diagram 3] FIG. 3 is a flowchart showing an example of a process executed by the control device 20 that controls the vehicle 10 for transitioning from the EV driving mode to the hybrid driving mode. [Figure 4] FIG. 4 is a diagram showing a specific example of a transition of driving modes in the vehicle 10. As shown in FIG. [Diagram 5] FIG. 5 is a diagram showing an example of how the actual vehicle required electric power and the predicted vehicle required electric power rise when the required driving force increases. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a vehicle control device of the present invention will be described in detail with reference to the drawings. Note that not all of the features described in the following embodiment are necessarily essential to the present invention. In addition, two or more of the features described in the following embodiment may be arbitrarily combined. In the following, identical or similar elements are denoted by identical or similar reference symbols, and their descriptions may be omitted or simplified as appropriate.

[0013] [vehicle] First, a vehicle equipped with a control device (a control device 20 described below) which is one embodiment of a vehicle control device of the present invention will be described.

[0014] As shown in Fig. 1, a vehicle 10 of this embodiment is a hybrid electric vehicle, and 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. In Fig. 1, thick solid lines indicate mechanical connections, double dotted lines indicate electrical wiring, and thin solid arrows indicate transmission and reception of control signals or detection signals.

[0015] The engine ENG is an internal combustion engine such as a gasoline engine or a diesel engine, and outputs power generated by combusting supplied fuel. The engine ENG is connected to a second motor generator MG2 and is connected to driving wheels DW of the vehicle 10 via a clutch CL. The power output by the engine ENG (hereinafter also referred to as "output of the engine ENG") is transmitted to the second motor generator MG2 when the clutch CL is in a disengaged state, and is transmitted to the second motor generator MG2 and the driving wheels DW when the clutch CL is in an engaged state (engaged state). The second motor generator MG2 and the clutch CL will be described later.

[0016] The first motor generator MG1 is a motor generator (a so-called "traction motor") mainly used as a drive source for the vehicle 10, and is configured, for example, by an AC motor. The first motor generator MG1 is electrically connected to a battery BAT and a second motor generator MG2 via a 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 an electric motor by being supplied with electric power, and outputs power for the vehicle 10 to run. The first motor generator MG1 is also connected to drive wheels DW, and the power output by the first motor generator MG1 (hereinafter also referred to as "output of the first motor generator MG1") is transmitted to the drive wheels DW. The vehicle 10 runs by transmitting at least one of the output of the engine ENG and the output of the first motor generator MG1 to the drive wheels DW.

[0017] Moreover, the first motor generator MG1 can also perform regenerative operation as a generator during braking of the vehicle 10 to generate electricity (so-called regenerative power generation). 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. This allows the battery BAT to be charged by the regenerative power.

[0018] Also, the regenerated power may be supplied to the second motor generator MG2 via the power conversion device 11 instead of being supplied to the battery BAT. By supplying the regenerated power to the second motor generator MG2, it is possible to perform "power disposal" in which the regenerated power is consumed without charging the battery BAT. Note that when disposing of power, the regenerated 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 consumed by mechanical friction loss of the engine ENG, etc.

[0019] The second motor generator MG2 is a motor generator mainly used as a power generator, and is configured, for example, by 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 by the electric power.

[0020] Furthermore, the second motor generator MG2 can also function as a starter motor that starts the engine ENG. That is, for example, when transitioning from an EV driving mode to a hybrid driving mode, which will be described later, electric power from the battery BAT is supplied to the second motor generator MG2, and the second motor generator MG2 driven by that electric power cranks the engine ENG, thereby starting the engine ENG.

[0021] The power conversion device 11 is a device (a so-called power control unit, also referred to as "PCU") that converts input power and outputs the converted power, and is connected to a first motor generator MG1, a second motor generator MG2, and a battery BAT. For example, the power conversion device 11 includes 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 to each other.

[0022] The voltage control device 110 converts an input voltage and outputs the converted voltage. A DC / DC converter or the like can be used as the voltage control device 110. For example, when the voltage control device 110 supplies power from the battery BAT to the first motor generator MG1, the voltage control device 110 boosts the output voltage of the battery BAT and outputs it to the first inverter 111. Also, for example, when regenerative power generation is performed by the first motor generator MG1, the voltage control device 110 reduces the output voltage of the first motor generator MG1 received via the first inverter 111 and outputs it to the battery BAT. Also, when power generation is performed by the second motor generator MG2, the voltage control device 110 reduces the output voltage of the second motor generator MG2 received via the second inverter 112 and outputs it to the battery BAT.

[0023] When the first inverter 111 supplies the power of the battery BAT 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 the power to the first motor generator MG1. When regenerative power is generated by the first motor generator MG1, the first inverter 111 converts the power (AC) received from the first motor generator MG1 into DC and outputs the DC to the voltage control device 110. When the regenerative power of the first motor generator MG1 is discarded, the first inverter 111 converts the power (AC) received from the first motor generator MG1 into DC and outputs the DC to the second inverter 112.

[0024] When power is generated by the second motor generator MG2, the second inverter 112 converts the power (AC) received from the second motor generator MG2 into DC and outputs the power to the voltage control device 110. When the regenerative power of the first motor generator MG1 is discarded, 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 the AC to the second motor generator MG2.

[0025] The battery BAT is a chargeable and dischargeable secondary battery, and has a plurality of storage cells connected in series or in series-parallel. The battery BAT is configured to be capable of outputting a high voltage of, for example, 100 to 400 V. The storage cells of the battery BAT may be lithium-ion batteries, nickel-metal hydride batteries, or the like.

[0026] The clutch CL can be in a connected state in which the power transmission path from the engine ENG to the drive wheels DW is connected (engaged) and in a disconnected state in which the power transmission path from the engine ENG to the drive wheels DW is disconnected (disconnected). When the clutch CL is in the connected state, the output of the engine ENG is transmitted to the drive wheels DW, and when the clutch CL is in the disconnected state, the output of the engine ENG is not transmitted to the drive wheels DW.

[0027] The various sensors 12 are sensors that obtain various information related to the vehicle 10. As shown in Fig. 1, the various sensors 12 include, for example, a vehicle speed sensor 12a that detects the traveling speed of the vehicle 10 (hereinafter also referred to as "vehicle speed"), an AP sensor 12b that detects an AP opening (AP: Accelerator Position) that indicates the amount of operation of an accelerator pedal of the vehicle 10, and a battery sensor 12c that detects information related to the battery BAT (for example, the output voltage, charge / discharge current, and temperature of the battery BAT). The detection results by the various sensors 12 are sent to the control device 20 as detection signals.

[0028] The control device 20 is a device (computer) that controls the entire vehicle 10, and is realized by, for example, an ECU (Electronic Control Unit) including a processor 21 that performs various calculations, a memory 22 that stores various information, and an I / F 23 (I / F: Interface) 23 that controls input and output of data between the inside and outside of the control device 20. The control device 20 may be realized by one ECU or multiple ECUs.

[0029] The control device 20 is provided to be able to communicate with the engine ENG, the clutch CL, the power conversion device 11, and various sensors 12. The control device 20 controls the output of the engine ENG by the processor 21 executing a program stored in the memory 22, controls the output of the first motor generator MG1 and the second motor generator MG2 by controlling the power conversion device 11, and controls the state of the clutch CL. This allows the control device 20 to control the driving mode of the vehicle 10, as described below.

[0030] For example, when the vehicle 10 is traveling, the control device 20 derives a required driving force (in other words, a driving force required for the vehicle 10 to travel) that is a target value for the driving force of the vehicle 10, based on the vehicle speed detected by the vehicle speed sensor 12a and the AP opening detected by the AP sensor 12b. Then, the control device 20 controls the output of the engine ENG and / or the first motor generator MG1, or controls the traveling mode of the vehicle 10, so that the driving force of the vehicle 10 becomes the required driving force. Note that the required driving force derived by the control device 20 becomes larger as the vehicle speed is higher and as the AP opening is larger.

[0031] [Vehicle driving mode] Here, the driving modes that the vehicle 10 can take will be described. The driving modes that the vehicle 10 can take are an EV driving mode, a hybrid driving mode, and an engine driving mode. The vehicle 10 runs in one of these multiple driving modes. As described above, the control device 20 controls in which driving mode the vehicle 10 runs.

[0032] [EV driving mode] The EV driving mode is an example of a first driving mode in the present invention, and is a driving mode in which 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 in response to the supplied electric power. The EV driving mode is a driving mode in which the vehicle travels by driving the drive wheels DW only by the first motor generator MG1 out of the engine ENG and the first motor generator MG1.

[0033] Specifically, in the EV driving mode, the control device 20 disengages the clutch CL. In addition, in the EV driving mode, the control device 20 stops the supply of fuel to the engine ENG and stops the output of power from the engine ENG (hereinafter also referred to as "operation of the engine ENG"). As a result, in the EV driving mode, power is not generated by the second motor generator MG2. In the EV driving mode, the control device 20 supplies only the power of the battery BAT to the first motor generator MG1 and causes the first motor generator MG1 to output power corresponding to that power, and the vehicle 10 is driven by that power.

[0034] Basically, the control device 20 causes the vehicle 10 to run in the EV driving mode on the condition that the electric power required by the vehicle 10 (hereinafter also referred to as "vehicle required electric power") is equal to or less than a predetermined threshold value (hereinafter also referred to as "EV permitted electric power"). The vehicle required electric power in the EV driving mode includes the electric power required to run the vehicle 10 by the first motor generator MG1, and varies according to the required driving force and the vehicle speed.

[0035] [Hybrid driving mode] The hybrid driving mode is an example of the second driving mode in the present invention, and is a driving mode in which at least 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 power output by the first motor generator MG1 in response to the electric power. The hybrid driving mode is a driving mode in which the vehicle travels by driving the drive wheels DW only by the first motor generator MG1 out of the engine ENG and the first motor generator MG1.

[0036] Specifically, in the hybrid driving mode, the control device 20 puts the clutch CL into a disengaged state. In addition, in the hybrid driving mode, the control device 20 supplies fuel to the engine ENG to cause the engine ENG to output power, and drives the second motor generator MG2 with the power of the engine ENG. As a result, in the hybrid driving mode, power is generated by the second motor generator MG2. In addition, in the hybrid driving mode, the control device 20 puts the power transmission path into a disengaged state by the clutch CL, supplies electric power generated by the second motor generator MG2 to the first motor generator MG1, causes the first motor generator MG1 to output power corresponding to the electric power, and drives the vehicle 10 with the power.

[0037] The electric power supplied from the second motor generator MG2 to the first motor generator MG1 is greater than the electric power supplied from the battery BAT to the first motor generator MG1. Therefore, in the hybrid driving mode, the output of the first motor generator MG1 can be made greater than in the EV driving mode, and a greater driving force can be obtained.

[0038] In the hybrid driving mode, the control device 20 may also supply the electric power of the battery BAT to the first motor generator MG1 as necessary. That is, in the hybrid driving mode, the control device 20 may supply the electric power of both the second motor generator MG2 and the battery BAT to the first motor generator MG1. This makes it possible to increase the electric power supplied to the first motor generator MG1 compared to the case where only the electric power of the second motor generator MG2 is supplied to the first motor generator MG1, thereby obtaining even greater driving force.

[0039] [Engine driving mode] The engine drive mode is a drive mode in which the vehicle 10 is driven mainly by the power output by the engine ENG, and is a drive mode in which the vehicle 10 is driven by at least the engine ENG driving the drive wheels DW.

[0040] Specifically, in the engine driving mode, the control device 20 connects the clutch CL. Also, in the engine driving mode, the control device 20 supplies fuel to the engine ENG to cause the engine ENG to output power. In the engine driving mode, the power transmission path is connected by the clutch CL, so that the power of the engine ENG is transmitted to the drive wheels DW to drive the drive wheels DW. Thus, in the engine driving mode, the control device 20 causes the engine ENG to output power and causes the vehicle 10 to run using that power.

[0041] In addition, in the engine running mode, the control device 20 may supply the electric power of the battery BAT to the first motor generator MG1 as necessary. As a result, in the engine running mode, the vehicle 10 can be run using the power output by the first motor generator MG1 by supplying the electric power of the battery BAT, 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, as a result, the output of the engine ENG can be suppressed compared to the case where the vehicle 10 is run only by the power of the engine ENG, and the fuel efficiency of the vehicle 10 can be improved.

[0042] [Control performed by the control device of this embodiment] Next, the control performed by the control device 20 will be described in more detail.

[0043] The electric power required by the vehicle in the EV driving mode changes from moment to moment and may momentarily exceed the EV permitted electric power. If the EV driving mode is switched to the hybrid driving mode even when the electric power required by the vehicle momentarily exceeds the EV permitted electric power, the transition from the EV driving mode to the hybrid driving mode may occur frequently. Since the transition from the EV driving mode to the hybrid driving mode is accompanied by starting of the engine ENG, if such transitions occur frequently, this leads to a deterioration in the NV (Noise, Vibration) characteristics and fuel economy of the vehicle 10. Therefore, it is desirable to suppress excessive transitions from the EV driving mode to the hybrid driving mode.

[0044] Therefore, in this embodiment, when the vehicle 10 is in the EV driving mode, the transition from the EV driving mode to the hybrid driving mode is made based on the fact that the state in which the vehicle required power exceeds the EV permitted power (i.e., a predetermined threshold) continues for a predetermined delay time. This delay time is made to vary depending on the remaining charge of the battery BAT (hereinafter also simply referred to as "SOC (State Of Charge)").

[0045] Therefore, according to this embodiment, it is possible to prevent a situation in which the EV driving mode is switched to the hybrid driving mode only when the state in which the vehicle required power exceeds the EV permitted power continues for a short period of time even when the SOC is abundant. This makes it possible to prevent an excessive transition from the EV driving mode to the hybrid driving mode, and to prevent the NV characteristics and fuel economy of the vehicle 10 from deteriorating due to such a transition. Furthermore, according to this embodiment, when the SOC is not abundant, the transition from the EV driving mode to the hybrid driving mode is quickly performed, thereby preventing the SOC from dropping too much.

[0046] An example of the process executed by the control device 20 when the vehicle 10 is in the EV driving mode will be described below with reference to Figures 2 and 3. This process is executed, for example, by the processor 21 of the control device 20 executing a program stored in advance in the memory 22. In addition, the series of processes shown in Figure 2 and the series of processes shown in Figure 3 are repeatedly executed at a predetermined cycle (for example, every 5 [ms]) when the driving mode of the vehicle 10 is the EV driving mode.

[0047] As shown in Fig. 2, the control device 20 first derives the electric power required by the vehicle (step S1). The electric power required by the vehicle in the EV driving mode can be derived, for example, based on a TRC torque required value (TRC: Traction) which is a target value of the torque generated by the first motor generator MG1, and the TRC rotation speed which is the rotation speed of the first motor generator MG1. Here, the TRC torque required value can be obtained, for example, from the required driving force. Also, the TRC rotation speed can be obtained, for example, from the vehicle speed detected by the vehicle speed sensor 12a. The electric power required by the vehicle increases as the TRC torque required value and the TRC rotation speed increase, in other words, as the required driving force and the vehicle speed increase.

[0048] Furthermore, the control device 20 may derive the electric power required for the vehicle by taking into consideration not only the power consumption by the first motor generator MG1 but also the power consumption by auxiliary devices (eg, an air conditioner, a cooling device, etc.) provided in the vehicle 10.

[0049] For example, in this case, the various sensors 12 include a sensor that detects the power consumption of the auxiliary devices provided in the vehicle 10, and the control device 20 acquires the power consumption of the auxiliary devices based on the detection result of this sensor. When the vehicle 10 is in the EV driving mode, the control device 20 derives the sum of the power required for driving the vehicle 10 by the first motor generator MG1 and the acquired power consumption of the auxiliary devices as the vehicle required power. In this way, it is possible to derive a more accurate vehicle required power with respect to the power actually required by the vehicle 10, and it is possible to more appropriately perform various processes using the vehicle required power. In addition, the control device 20 may acquire the power consumption of the auxiliary devices by estimating the power consumption of the auxiliary devices from, for example, the operating state of the auxiliary devices.

[0050] Next, the control device 20 derives ΔEV permitted power, which is the difference between the vehicle requested power and the EV permitted power, based on the vehicle requested power derived in the process of step S1 and a preset EV permitted power (step S2). In the process of step S2, the control device 20 derives, for example, a value obtained by subtracting the EV permitted power from the vehicle requested power as the ΔEV permitted power.

[0051] Next, the control device 20 derives a delay time corresponding to the combination of the ΔEV allowed power and SOC based on the ΔEV allowed power derived by the process of step S2 and the current SOC (i.e., the remaining capacity of the battery BAT) (step S3). In the process of step S3, the control device 20 derives the delay time corresponding to the combination of the ΔEV allowed power and SOC by using, for example, a table (information) that specifies the delay time for each combination of the ΔEV allowed power and SOC or a predetermined calculation formula.

[0052] The delay time derived by the process of step S3 is designed to be shorter as the ΔEV permitted power is larger and longer as the SOC is higher, for example, as shown in the balloon of symbol α in Fig. 2. That is, the control device 20 shortens the delay time as the ΔEV permitted power is larger and lengthens the delay time as the SOC is higher.

[0053] By shortening the delay time as the ΔEV permitted power is larger, for example, when the required driving force is large and the vehicle required power is large, the transition from the EV driving mode to the hybrid driving mode can be made quickly. This makes it possible to prevent the EV driving mode, in which the required driving force cannot be secured, from continuing for a long period of time and causing the drivability of the vehicle 10 to deteriorate. In addition, by lengthening the delay time as the SOC is higher, it is possible to prevent the NV characteristics and fuel efficiency of the vehicle 10 from deteriorating due to an excessive transition from the EV driving mode to the hybrid driving mode, as described above. The SOC can be obtained, for example, from the detection result of the battery sensor 12c.

[0054] Next, the control device 20 sets the delay time derived by the process of step S3 as one of the conditions for determining whether or not to transition from the EV driving mode to the hybrid driving mode (step S4), and ends the series of processes shown in FIG.

[0055] 3, the control device 20 determines whether or not a delay flag is on (step S11). Although details will be described later, this delay flag is a flag that is set on when the electric power required for the vehicle exceeds the EV permitted electric power.

[0056] If it is determined that the delay flag is off (step S11: NO), the control device 20 determines whether the vehicle required electric power derived by the most recent process of step S1 is greater than the EV permitted electric power (step S12). If it is determined that the vehicle required electric power is not greater than the EV permitted electric power (step S12: NO), the control device 20 ends the series of processes shown in FIG.

[0057] When it is determined that the vehicle requested electric power is greater than the EV permitted electric power (step S12: YES), the control device 20 starts measuring the elapsed time (step S13) and sets the delay flag to ON (step S14).

[0058] Next, the control device 20 judges whether the elapsed time that has been measured since the process of step S13 has reached or exceeded the delay time set by the process of the most recent step S4 (step S15). If it is judged that the elapsed time has not reached or exceeded the delay time (step S15: NO), the control device 20 ends the series of processes shown in FIG.

[0059] When it is determined that the elapsed time is equal to or 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 that began to be measured in the process of step S13 to "0" (step S17). Then, the control device 20 shifts the driving mode of the vehicle 10 from the EV driving mode to the hybrid driving mode (step S18), and ends the series of processes shown in FIG.

[0060] If it is determined in the process of step S11 that the delay flag is on (step S11: YES), the control device 20 determines whether the electric power required for the vehicle is greater than the EV permitted electric power (step S19), similarly to the process of step S12 described above. If it is determined that the electric power required for the vehicle is greater than the EV permitted electric power (step S19: YES), the control device 20 proceeds to the process of step S15 described above.

[0061] If it is determined that the vehicle required power is not greater than the EV permitted power (step S19: NO), the control device 20 sets the delay flag to OFF (step S20), and resets the elapsed time that began to be measured by the processing of step S13 to "0" (step S21), and ends the series of processing shown in FIG. 3.

[0062] [Example of Transition between Specific Driving Modes in the Vehicle of the Present Embodiment] Next, with reference to FIG. 4, an example of the transition between specific driving modes in the vehicle 10 will be described. In (a) of FIG. 4, the vertical axis represents the vehicle required power, and the horizontal axis represents the time. In (b) of FIG. 4, the vertical axis represents the SOC, and the horizontal axis represents the time. (c) of FIG. 4 represents the driving mode of the vehicle 10 at each time.

[0063] In the example shown in FIG. 4, each of the period Ta from time t1 to time t2, the period Tb from time t4 to time t5, and the period Tc from time t7 to time t9 is a period during which the vehicle required power is greater than the EV permitted power.

[0064] Also, 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". Then, 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".

[0065] In the case of this example, the time t2 when the vehicle required power becomes less than or equal to the EV permitted power immediately after time t1 is a time earlier than time t3 when a time of "Dx" has elapsed from time t1. Therefore, during the period from time t1 to time t2, although the vehicle required power exceeds the EV permitted power, the control device 20 maintains the EV driving mode without shifting to the hybrid driving mode.

[0066] Similarly, time t5 when the electric power required for the vehicle becomes equal to or less than the EV permitted electric power immediately after time t4 is a time before time t6 when a time period "Dy" has elapsed since time t4. Therefore, although the electric power required for the vehicle exceeds the EV permitted electric power during the period from time t4 to time t5, the control device 20 maintains the EV driving mode without transitioning to the hybrid driving mode.

[0067] On the other hand, time t9 when the vehicle required power becomes equal to or less than the EV permitted power immediately after time t7 is later than time t8 when a time period "Dz" has elapsed since time t7. In other words, even if a delay time "Dz" has elapsed since time t7 when the vehicle required power exceeded the EV permitted power, the state in which the vehicle required power exceeds the EV permitted power continues. Therefore, in this case, the control device 20 transitions 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 from time t8 when the delay time "Dz" has elapsed since time t7 when the vehicle required power exceeded the EV permitted power to time t9 when the vehicle required power becomes equal to or less than the EV permitted power.

[0068] As described above, when the vehicle 10 is in the EV driving mode, the control device 20 transitions 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 permitted power continues for a delay time according to the SOC. This allows the transition from the EV driving mode to the hybrid driving mode to be appropriately performed taking the SOC into consideration, and prevents the NV characteristics and fuel economy of the vehicle 10 from deteriorating due to an excessive transition from the EV driving mode to the hybrid driving mode. This can in turn contribute to improving energy efficiency.

[0069] Incidentally, the vehicle speed may be higher at a time after the time when the vehicle required power exceeds the EV permitted power (for example, at time t7 in FIG. 4) (for example, at time t8 in FIG. 4), and the vehicle required power may also be larger accordingly.

[0070] Furthermore, when the vehicle 10 transitions from the EV driving mode to the hybrid driving mode, the electric power of the battery BAT is supplied to the second motor generator MG2, and the engine ENG is started by cranking the engine ENG using the second motor generator MG2. Therefore, when transitioning from the EV driving mode to the hybrid driving mode, the electric power output from the battery BAT increases by the amount of the electric power supplied to the second motor generator MG2.

[0071] For the above reasons, if the transition from the EV driving mode to the hybrid driving mode is made after the time when the electric power required for the vehicle exceeds the EV permitted electric power, the electric power output from the battery BAT at the time of the transition may become excessive, and accordingly, the battery loss, which is the electric power consumption caused by the internal resistance of the battery BAT, may also become large. From the viewpoint of suppressing such an increase in battery loss, it is preferable to transition from the EV driving mode to the hybrid driving mode before the electric power required for the vehicle becomes too large.

[0072] Therefore, the control device 20 may predict the vehicle speed a predetermined time from the present based on the required driving force and the weight of the vehicle 10, assuming that the required driving force is generated, and derive the vehicle required power using the predicted vehicle speed (hereinafter also referred to as the "predicted vehicle speed").

[0073] Here, the predetermined time (for example, the predetermined time T shown in FIG. 5) is, for example, a time equal to or less than the minimum delay time Dmin that can be derived as a processing result of step S3, and is set in advance by the manufacturer of the vehicle 10, etc. This makes it possible to predict, as the predicted vehicle speed, a vehicle speed suitable for use in the processing related to the transition from the EV driving mode to the hybrid driving mode.

[0074] Specifically, in this case, the control device 20 determines the TRC rotation speed using the predicted vehicle speed instead of the vehicle speed detected by the above-mentioned vehicle speed sensor 12a (hereinafter also referred to as "actual vehicle speed"), and derives the vehicle required power using this TRC rotation speed. The predicted vehicle speed can be determined, for example, by solving the equation of motion for the vehicle 10. In the following, the vehicle required power derived using the actual vehicle speed is also referred to as "actual vehicle required power", and the vehicle required power derived using the predicted vehicle speed instead of the actual vehicle speed is also referred to as "predicted vehicle required power".

[0075] Here, with reference to Fig. 5, an example of how the actual vehicle required power and the predicted vehicle required power rise when the required driving force increases will be described. In Fig. 5(a), the vertical axis represents the required driving force, and the horizontal axis represents the time. In Fig. 5(b), the vertical axis represents the actual vehicle speed and the predicted vehicle speed, and the horizontal axis represents the time. In Fig. 5(c), the vertical axis represents the actual vehicle required power and the predicted vehicle required power, and the horizontal axis represents the time.

[0076] In the example shown in Fig. 5, at time t11, the driver of the vehicle 10 depresses the accelerator pedal, and the requested driving force increases in response to this operation. Normally, even if the requested driving force increases in this way, there is a time lag before the vehicle 10 accelerates (in other words, the actual vehicle speed increases), as shown in Fig. 5. For this reason, the rise in the actual vehicle requested electric power based on the actual vehicle speed also lags behind time t11 when the requested driving force increases.

[0077] In contrast, as shown in Fig. 5, the predicted vehicle speed rises earlier than the actual vehicle speed by a predetermined time T. Therefore, the predicted vehicle required power based on the predicted vehicle speed also rises earlier than the actual vehicle required power by the predetermined time T.

[0078] For example, the predicted vehicle speed at time t12 immediately after time t11 will be approximately the same as the actual vehicle speed at time t13 a predetermined time T has elapsed since time t12, and the predicted vehicle required power at time t12 will be approximately the same as the actual vehicle required power at time t13.

[0079] Therefore, by performing the process for the transition from the EV driving mode to the hybrid driving mode using such predicted vehicle required electric power, it is possible to accelerate the transition from the EV driving mode to the hybrid driving mode, i.e., the start of the engine ENG, as shown by the white arrow with symbol β in Fig. 5. This makes it possible to reduce the electric power output from the battery BAT when transitioning from the EV driving mode to the hybrid driving mode, and suppress battery loss during the transition, compared to when the process for the transition from the EV driving mode to the hybrid driving mode is performed using the actual vehicle required electric power.

[0080] Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to this embodiment. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

[0081] The control method described in this embodiment can be realized by executing a prepared program (control program) on a computer. The control program is stored in a computer-readable storage medium (e.g., memory 22) and is executed by being read from the storage medium. The control program may be provided in a form stored in a non-volatile (non-transient) storage medium such as a flash memory, or provided via a network such as the Internet.

[0082] In the present embodiment, the computer that executes the control program is the control device 20, and the processor 21 of the control device 20 executes the control program to realize the above-mentioned control method, but this is not limited to this. The computer that executes the control program is not limited to one included in the vehicle 10, and may be, for example, one included in a server device that can communicate with the vehicle 10 (control device 20).

[0083] This specification etc. describes at least the following items. In parentheses, components etc. corresponding to the above-mentioned embodiment are shown as examples, but the present invention is not limited to these.

[0084] (1) A vehicle control device (control device 20) that controls 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) that drives drive wheels in response to electric power supply from at least one of the generator and the power storage device, The vehicle is The vehicle is configured to be capable of traveling in any one of a plurality of traveling modes including a first traveling mode in which the operation of the internal combustion engine is stopped and the electric motor drives the drive wheels in response to the supply of electric power from the power storage device, and a second traveling mode in which the internal combustion engine is operated and the electric motor drives the drive wheels in response to at least the supply of electric power from the generator, The vehicle control device includes: transitioning the vehicle from the first traveling mode to the second traveling mode based on a state in which a vehicle required electric power required by the vehicle exceeds a threshold value for a predetermined delay time when the vehicle is in the first traveling mode; The delay time is varied depending on the remaining capacity of the power storage device. A processor (processor 21) for performing processing is provided. Vehicle control device.

[0085] According to (1), it is possible to prevent a situation in which the first driving mode is switched to the second driving mode when the vehicle required power exceeds the threshold value for only a short period of time, even if the remaining charge of the power storage device is ample. This makes it possible to prevent excessive switching from the first driving mode to the second driving mode, and to prevent deterioration of the vehicle's NV (Noise, Vibration) characteristics and fuel economy caused by such switching. Furthermore, according to (1), when the remaining charge of the power storage device is not ample, it is possible to prevent the remaining charge of the power storage device from decreasing too much by quickly switching from the first driving mode to the second driving mode.

[0086] (2) A vehicle control device according to (1), The processor extends the delay time as the remaining charge of the power storage device increases. Vehicle control device.

[0087] According to (2), it is possible to prevent the deterioration of the NV characteristics and fuel economy of the vehicle caused by excessive transition from the first driving mode to the second driving mode.

[0088] (3) A vehicle control device according to (2), The vehicle required electric power increases as the required driving force of the vehicle increases, The processor further shortens the delay time as the difference between the vehicle required electric power and the threshold value increases. Vehicle control device.

[0089] According to (3), when the required driving force is large and the electric power required by the vehicle is large, the transition from the first driving mode to the second driving mode can be performed quickly. This makes it possible to prevent the first driving mode, in which the required driving force cannot be secured, from continuing for a long period of time, which would deteriorate the drivability of the vehicle.

[0090] (4) A vehicle control device according to any one of (1) to (3), When the vehicle is in the first traveling mode, the processor derives, as the vehicle required electric power, a sum of electric power required for driving the vehicle by the electric motor and electric power consumed by an auxiliary device provided in the vehicle. Vehicle control device.

[0091] According to (4), a more accurate vehicle required power can be derived from the power actually required in the vehicle, and various processes can be more appropriately performed using the vehicle required power.

[0092] (5) A vehicle control device according to any one of (1) to (3), the processor predicts a traveling speed of the vehicle after a predetermined time 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 electric power using the predicted traveling speed. Vehicle control device.

[0093] According to (5), compared to a case in which the vehicle required power is derived using the actual vehicle speed and the vehicle required power is used to process the transition from the first driving mode to the second driving mode, the timing of the transition from the first driving mode to the second driving mode can be advanced, thereby reducing the power output from the storage device during the transition and suppressing losses due to the internal resistance of the storage device during the transition.

[0094] (6) A vehicle control device according to (5), The predetermined time is equal to or less than the delay time. Vehicle control device.

[0095] According to (6), it is possible to predict a traveling speed suitable for use in the process related to the transition from the first traveling mode to the second traveling mode. [Explanation of symbols]

[0096] 10 Vehicles 20 Control device (vehicle control device) 21 Processors BAT Battery (energy storage device) ENG Engine (internal combustion engine) MG1 First motor generator (electric motor) MG2 Second motor generator (generator)

Claims

1. A vehicle control device that controls a vehicle including an internal combustion engine, a generator driven by the internal combustion engine, a power storage device, and an electric motor that drives drive wheels in response to electric power supply from at least one of the generator and the power storage device, The vehicle is The vehicle is configured to be capable of traveling in any one of a plurality of traveling modes including a first traveling mode in which the operation of the internal combustion engine is stopped and the electric motor drives the drive wheels in response to the supply of electric power from the power storage device, and a second traveling mode in which the internal combustion engine is operated and the electric motor drives the drive wheels in response to at least the supply of electric power from the generator, The vehicle control device includes: transitioning the vehicle from the first traveling mode to the second traveling mode based on a state in which a vehicle required electric power required by the vehicle exceeds a threshold value for a predetermined delay time when the vehicle is in the first traveling mode; The delay time is varied depending on the remaining capacity of the power storage device. A processor for performing processing, Vehicle control device.

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

3. The vehicle control device according to claim 2, The vehicle required electric power increases as the required driving force of the vehicle increases, The processor further shortens the delay time as the difference between the vehicle required electric power and the threshold value increases. Vehicle control device.

4. A vehicle control device according to any one of claims 1 to 3, When the vehicle is in the first traveling mode, the processor derives, as the vehicle required electric power, a sum of electric power required for driving the vehicle by the electric motor and electric power consumed by an auxiliary device provided in the vehicle. Vehicle control device.

5. A vehicle control device according to any one of claims 1 to 3, the processor predicts a traveling speed of the vehicle after a predetermined time 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 electric power using the predicted traveling speed. Vehicle control device.

6. The vehicle control device according to claim 5, The predetermined time is equal to or less than the delay time. Vehicle control device.

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