Vehicle control method and vehicle control device

Abstract

Provided is a control method for a vehicle comprising: a generator; an engine connected to the generator; a drive motor that drives the vehicle; and a battery electrically connected to the generator and the drive motor. In the vehicle, power generated by the generator is supplied to at least one of the battery and the drive motor. The control method includes: if a temperature of the battery is a predetermined temperature or lower, calculating a drive torque target value on the basis of vehicle requested power and the state of the battery; torque-controlling the generator on the basis of the drive torque target value; and rotation speed-controlling the engine, on the basis of a predetermined reference low rotation speed, to execute low power generation control for generating power by the generator.

Description

[Technical field]

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

[0002] JP2004-300957A discloses a technique for feedback control so that the engine speed becomes a target speed during engine idling. In this technique, a generator is connected to the output shaft of the engine, and if the actual engine speed is higher than the target speed, the generator is controlled to absorb the torque generated by the engine, and if the actual engine speed is lower than the target speed, the generator is controlled to impart torque to the engine. Summary of the Invention

[0003] In the above-mentioned conventional technology, even if the engine speed fluctuates due to the occurrence of a load or the like during engine idling, the engine speed can be converged to a target idle speed. However, in a series hybrid vehicle configured to be able to charge the battery by driving a generator with the engine, the engine is idled when warming up the engine and battery, and in this case the battery is not charged. In addition, in a low-temperature environment, the chargeable power of the battery is reduced, making it difficult to charge the battery. Therefore, in such a low-temperature environment, if the engine is idled for a long time, the battery is not charged for a long time, and the SOC of the battery may continue to decrease due to the power consumption of the vehicle drive and auxiliary equipment.

[0004] The present invention aims to ensure the electric power necessary to drive the vehicle and operate the auxiliary machinery, and to reduce the risk of the vehicle running out of electricity.

[0005] One aspect of the present invention is a method for controlling a vehicle that includes a generator, an engine connected to the generator, a drive motor that drives the vehicle, and a battery electrically connected to the generator and the drive motor, and in which electric power generated by the generator is supplied to at least one of the battery and the drive motor. When the temperature of the battery is equal to or lower than a predetermined temperature, this control method executes low-power generation control to generate electric power by calculating a drive torque target value based on the required electric power of the vehicle and the state of the battery, performing torque control of the generator based on the drive torque target value, and controlling the rotation speed of the engine based on a predetermined reference low-speed rotation speed. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a vehicle. [Diagram 2] FIG. 2 is a block diagram illustrating a schematic configuration example of a control device for a vehicle. [Diagram 3] FIG. 3 is a block diagram illustrating a schematic configuration example of a control device for a vehicle according to a comparative example. [Figure 4] FIG. 4 is a block diagram illustrating a schematic configuration example of a control device for a vehicle. [Diagram 5] FIG. 5 is a flowchart showing an example of a control process in the control device of the vehicle. [Figure 6] FIG. 6 is a flowchart showing an example of a control process in the control device of the vehicle. [Figure 7] FIG. 7 is a diagram showing an example of setting the torque and rotation speed in the low power generation control state. [Figure 8] FIG. 8 is a flowchart showing an example of a control process in the control device of the vehicle. [Figure 9] FIG. 9 is a diagram showing an example of switching the engine speed in response to the vehicle speed in the low power generation control state. [Figure 10] FIG. 10 is a diagram showing an example of switching the engine speed in response to the vehicle speed in the low power generation control state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0008] [Vehicle configuration example] 1 is a diagram showing a schematic configuration of a vehicle 1. The vehicle 1 is a series hybrid vehicle, and in this embodiment, a power generation control system for a series hybrid vehicle will be mainly described.

[0009] The vehicle 1 includes an engine 10, a generator 20, a battery 40, a drive motor 50, accessories 60, a gear 71, and drive wheels 72. The vehicle 1 uses the engine 10 to drive the generator 20 to generate electricity, and the drive motor 50 is driven by the electricity generated by the generator 20.

[0010] The engine 10 is an internal combustion engine, for example a gasoline engine. The engine 10 is connected to a generator 20 so as to be capable of transmitting power. The generator 20 is a motor generator, which generates power and also motors the engine 10. Motoring is performed by driving the engine 10, which is in a stopped state, with the generator 20. The drive motor 50 is a motor generator, which generates driving force for the vehicle 1. The driving force generated by the drive motor 50 is transmitted to drive wheels 72 via gear 71, which is a reduction gear. The drive motor 50 is driven by power from the drive wheels 72, and thereby also regenerates energy. The energy regenerated by the drive motor 50 as electric power can be charged to the battery 40.

[0011] The battery 40 stores electric power generated by the generator 20 and electric power regenerated by the drive motor 50. For example, a lithium ion secondary battery can be used as the battery 40. A discharge required SOC (State Of Charge) is set for the battery 40. The SOC is a parameter that indicates the state of charge of the battery 40, and the discharge required SOC is set in advance as a value for defining the fully charged state of the battery 40. In other words, the fully charged state of the battery 40 is defined by the discharge required SOC, and for example, a state where the SOC as a charging rate is 90% is considered to be fully charged.

[0012] In the power generation control system shown in this embodiment, the drive wheels 72 and the engine 10 are independent, and the engine 10 is connected only to the generator 20. The engine 10 and the generator 20 function as a power generation unit and constitute a power generation system.

[0013] The auxiliary devices 60 are devices that require electric power and are installed in the vehicle 1. For example, the auxiliary devices 60 include lights, speakers, a car navigation system, and an air conditioner.

[0014] The vehicle 1 further includes an engine controller 11, a generator controller 21, a vehicle controller 30, a battery controller 41, and a drive motor controller 51. The engine controller 11, the generator controller 21, the vehicle controller 30, the battery controller 41, and the drive motor controller 51 are connected to each other so as to be able to communicate with each other. The vehicle controller 30 is composed of one or more microcomputers including a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The vehicle controller 30 can also be called a VCM (Vehicle Control Module). In the vehicle controller 30, various controls are performed by the CPU executing a program stored in the ROM or RAM. The same is true for the engine controller 11, the generator controller 21, the battery controller 41, and the drive motor controller 51.

[0015] The generator controller 21 controls the generator 20. The generator controller 21 further includes a first inverter which is an inverter for the generator 20. The first inverter may have a configuration separate from the generator controller 21. The generator controller 21 controls the generator 20 by controlling the first inverter.

[0016] The drive motor controller 51 controls the drive motor 50. The drive motor controller 51 further includes a second inverter which is an inverter for the drive motor 50. The second inverter may be configured separately from the drive motor controller 51. The drive motor controller 51 controls the drive motor 50 by controlling the second inverter.

[0017] The first inverter is connected to the generator 20 and the battery 40. The first inverter converts the AC current supplied from the generator 20 into a DC current and supplies it to the battery 40. As a result, the battery 40 is charged with the power generated by the generator 20. The first inverter further converts the DC current supplied from the battery 40 into an AC current and supplies it to the generator 20. As a result, the generator 20 is driven by the power of the battery 40. Signals such as current, voltage, and SOC are also input to the generator controller 21 from the generator 20, the drive motor 50, and the battery 40. The same applies to the relationship between the second inverter, the drive motor 50, and the battery 40.

[0018] The engine controller 11 controls the engine 10. For example, the engine controller 11 controls a throttle valve, a fuel injection valve, a spark plug, etc., and performs engine control by adjusting the intake amount, the injection amount, the ignition timing, etc. Note that the engine control signal can be further input to the vehicle controller 30 via the engine controller 11.

[0019] The vehicle controller 30 comprehensively controls the engine 10, the generator 20, the battery 40, the drive motor 50, etc. Signals are input to the vehicle controller 30 from an accelerator opening sensor 91 for detecting an accelerator opening APO and a shift position sensor 92 for detecting a shift position (range) selected by a driver operation.

[0020] [Control device configuration example] 2 and 4 are block diagrams that show a typical configuration example of a control device 100 of a vehicle 1. FIG. 3 is a block diagram that shows a typical configuration example of a control device of a vehicle according to a comparative example. The control device 100 of the vehicle 1 is a device for executing power generation control in the vehicle 1, and includes an engine 10, a generator 20, a battery 40, and the like. Note that FIGS. 2 to 4 show examples of relationships when power generation control and engine control are executed in the vehicle.

[0021] FIG. 2 shows an example of the relationship in a normal power generation control state, FIG. 3 shows an example of the relationship in an Engine Idle Speed ​​Control (E-ISC) state as a comparative example, and FIG. 4 shows an example of the relationship in a low power power generation control state.

[0022] In the vehicle 1, the electric power generated by the generator 20 is supplied to the battery 40, the drive motor 50, or the auxiliary machinery 60. In addition, the sum of the electric power generated by the generator 20 and the electric power of the battery 40 is supplied to the drive motor 50 and the auxiliary machinery 60.

[0023] [Normal power generation control example] As shown in FIG. 2, in the normal power generation control state, the vehicle controller 30 outputs a torque command to the engine controller 11 and outputs a rotation speed command to the generator controller 21. That is, in the normal power generation control state, in consideration of the rotation speed controllability (response speed and accuracy), a rotation speed command is output to the generator 20 side and a torque command is output to the engine 10 side. In this case, the generator 20 side executes feedback control of the rotation speed based on the target rotation speed and the actual rotation speed, for example, PID control or rotation speed servo control, so that the target rotation speed corresponds to the rotation speed command. The actual rotation speed of the generator 20 can be detected by a rotation speed sensor, for example, a rotation phase angle sensor such as a resolver. As a result, the generator 20 controls the rotation speed of the engine 10, and the engine 10 generates torque required for power generation.

[0024] As shown in FIG. 2, in the normal power generation control state, the generator 20 generates a rotation speed maintenance torque to maintain the rotation speed of the engine 10. The rotation speed maintenance torque can be considered as a negative torque, a friction torque, or the like, when the shaft torque of the engine 10 is used as a reference. Specifically, the generator controller 21 executes switching control of the first inverter so that the engine 10 reaches a target rotation speed according to the rotation speed command output from the vehicle controller 30. That is, the generator 20 loads the rotation speed maintenance torque on the engine 10 by the switching control of the first inverter. For example, when the rotation speed of the generator 20 connected to the engine 10 is higher than the target rotation speed, the generator 20 applies a rotation speed maintenance torque to reduce the rotation speed of the generator 20, thereby suppressing the rotation of the engine 10. On the other hand, when the rotation speed of the generator 20 connected to the engine 10 is lower than the target rotation speed, the generator 20 rotation speed maintenance torque is reduced.

[0025] Thus, in the normal power generation control state, torque control is executed to increase or decrease the torque of the engine 10 so that it becomes the torque required for power generation, and rotation speed control is executed to increase or decrease the rotation speed of the generator 20 so that the rotation speed of the generator 20 becomes the rotation speed based on the torque required for power generation. That is, the generator 20 generates the torque required for power generation and the torque required to maintain the rotation speed, thereby generating power while maintaining the rotation speed of the engine 10. Also, the value obtained by multiplying the product of the torque generated by the generator 20 and the rotation speed of the generator 20 by a coefficient becomes the value of the generated power of the generator 20.

[0026] In addition, the engine 10 has a tendency to vary with respect to a torque command value, and often generates a torque that is large relative to the torque command value. In addition, it is known that the battery 40 has a tendency to have a small chargeable power PIN in a low temperature environment.

[0027] When the chargeable power PIN of the battery 40 decreases at low temperatures, the torque of the engine 10 is also set to a small value, and if the torque of the engine 10 varies greatly in this state, the generator 20 cannot absorb the torque variation, causing the engine 10 to rev up. In this state, i.e., when the chargeable power PIN is small and the variation in engine torque cannot be absorbed, it is possible to enter an E-ISC (Engine-Idle Speed ​​Control) state in which the engine 10 itself performs speed control. Thus, as a comparative example of this embodiment, an example in which E-ISC is performed is shown in FIG. 3.

[0028] [E-ISC as a comparison example] As shown in Fig. 3, in the E-ISC state, the vehicle controller 30 outputs an idle speed command to the engine controller 11, and outputs a command to stop switching control to the generator controller 21 so that switching control is not performed. In this way, by outputting an idle speed command to the engine controller 11, the engine 10 is controlled to the idle speed, so that the occurrence of revving can be suppressed. In this case, since switching control of the first inverter of the generator 20 is not performed, there is no output from the battery 40 to the first inverter, and no power is generated from the generator 20.

[0029] In this way, in the E-ISC state, the engine 10 is operated at an idle speed, and the generator 20 is in a no-load state. Therefore, the battery 40 is only discharging, and the SOC of the battery 40 continues to decrease.

[0030] In particular, if E-ISC is performed for a long period of time in a low temperature environment where the chargeable power PIN of the battery 40 decreases, the battery 40 will not be charged for a long period of time, and there is a risk of the battery running out of power due to power consumption by the drive motor 50 and auxiliary equipment 60 of the vehicle 1.

[0031] Therefore, in this embodiment, in order to reduce the risk of the vehicle 1 running out of power even when the chargeable power PIN drops, such as in a low-temperature environment, low-power generation is performed by the generator 20 when the engine 10 is caused to execute the speed control. That is, in this embodiment, when the chargeable power PIN drops, such as in a low-temperature environment, low-power generation is performed so that the SOC of the battery 40 is not lowered below a required amount, for example, a lower limit SOC value, so that the vehicle 1 does not run out of power, and the required amount of SOC of the battery 40 is secured. An example of this low-power generation control is shown in FIG. 4. The low-power generation control state can also be called a loaded ISC (Idle Speed ​​Control) state because the engine 10 is controlled in speed and the generator 20 is controlled in torque to execute power generation. In this embodiment, normal power generation control (see FIG. 2) and low-power power generation control (see FIG. 4) are switched between depending on the state of the battery 40 and the state of the vehicle, so that the minimum driving performance of the vehicle 1 is secured and the SOC of the battery 40 is prevented from running out.

[0032] [Example of low power generation control] As shown in Fig. 4, in the low power generation control state, the vehicle controller 30 outputs a rotation speed command to the engine controller 11, and outputs a torque command according to the state of the battery 40, for example, the chargeable power PIN, to the generator controller 21. That is, in the low power generation control state, a torque command is issued to the generator 20, so that generated power can be obtained during the rotation control by the engine 10. This makes it possible to suppress the speed of the engine 10 from increasing and the risk of the battery 40 running out of power.

[0033] The engine controller 11 also executes rotation speed control based on the rotation speed of the engine 10 detected by a rotation speed detection sensor, for example, a crank angle sensor. That is, the engine controller 11 calculates the difference between the detection value of the rotation speed detection sensor and a target value according to the rotation speed command, and executes rotation speed control by adjusting the air amount, fuel injection, throttle valve opening, ignition timing, etc. based on the difference value. By executing this rotation speed control, a rotation speed maintenance torque is output from the engine 10 side. In this way, in the low power generation control, a torque control is executed to increase or decrease the torque of the generator 20 so as to obtain the torque required for power generation, and a rotation speed control is executed to increase or decrease the rotation speed of the engine 10 so that the engine 10 reaches a predetermined reference low speed rotation speed.

[0034] As described above, in the low power generation control state, torque is generated in the generator 20 while the engine 10 is restricted to a predetermined low rotation speed. Therefore, if a torque command is set for the generator 20 without taking into account the response delay of the engine 10, there is a risk that the engine 10 will stall.

[0035] Therefore, when the vehicle controller 30 outputs a torque command to the generator 20, it is preferable that the vehicle controller 30 notifies the engine controller 11 of a value equal to the torque command as a target torque. This makes it possible to correct the reference torque when the engine 10 feeds back the rotation speed when torque is applied from the generator 20 to the engine 10, based on the target torque.

[0036] In this way, when the torque corresponding to the power to be generated is calculated, a torque command is issued to the generator 20 and at the same time, the torque to be generated on the engine 10 side, i.e., the target torque, is output. This makes it possible to improve the controllability of the rotation speed feedback.

[0037] Furthermore, the vehicle controller 30 acquires battery information regarding the battery 40 from the battery controller 41. This battery information includes a battery warm-up determination flag, a short-term chargeable power PIN_S, a long-term chargeable power PIN_L, and a low temperature upper limit SOC.

[0038] Here, the battery warm-up determination flag is a flag indicating whether or not the warm-up of the battery is completed. Specifically, when the battery warm-up determination flag is on, it indicates that the warm-up of the battery is completed, and when the battery warm-up determination flag is off, it indicates that the warm-up of the battery is not completed. In addition, when the cell temperature of the battery 40 is equal to or higher than the temperature threshold, the battery controller 41 outputs the battery warm-up determination flag as on to the vehicle controller 30, and when the cell temperature of the battery 40 is lower than the temperature threshold, it outputs the battery warm-up determination flag as off to the vehicle controller 30. This temperature threshold is a value that can determine a temperature at which the battery 40 can exhibit its performance, and can be appropriately set based on experimental data or the like. The battery controller 41 may determine whether or not the cell temperature of the battery 40 is equal to or lower than the temperature threshold based on the voltage of the battery 40 or the like.

[0039] The chargeable power PIN is information indicating the value of power that can be charged in the battery 40. The short-term chargeable power PIN_S is power that can be charged in the battery 40 for a short period of time. The short-term chargeable power PIN_S corresponds to power generated by an increase in engine speed after the engine 10 is started, or power that can absorb regenerative charging power while the vehicle is traveling (particularly at high speed). The time to determine the short-term chargeable power PIN_S is in the range of several seconds to several tens of seconds or less, and is determined by the time from the engine start to the increase in engine speed and / or the time required for the battery 40 to absorb large regenerative power generated during vehicle deceleration, and is at least shorter than the range of time to determine the long-term chargeable power PIN_L described later. The battery controller 41 calculates the short-term chargeable power PIN_S based on the SOC of the battery 40 and the temperature (battery temperature) of the battery 40.

[0040] The long-term chargeable power PIN_L is the power with which the battery 40 can be charged for a long period of time. The long-term chargeable power PIN_L corresponds to the chargeable power required to complete the warm-up of the battery 40 by charging. The time to determine the long-term chargeable power is within a range of several hundred seconds to several tens of minutes. The battery controller 41 calculates the long-term chargeable power PIN_L based on the SOC of the battery 40 and the temperature of the battery 40. In this way, the long-term chargeable power PIN_L means the power with which the battery 40 can be stably and continuously charged. The long-term chargeable power PIN_L functions as a chargeable power PIN at low temperatures based on a long-term second value that can be continuously used. The short-term chargeable power is also called instantaneous chargeable power, and the long-term chargeable power is also called continuous chargeable power.

[0041] The chargeable power PIN may be obtained by measuring the voltage and temperature of the battery 40. The chargeable power PIN may be obtained by measuring the voltage, current, and temperature of the battery 40. The chargeable power of the battery 40 may be obtained based on the short-term chargeable power PIN_S and the long-term chargeable power PIN_L. For example, at low temperatures, the chargeable power of the battery 40 decreases, but it is important to ensure a certain amount of charge. Therefore, for example, a value obtained by multiplying a difference between the long-term chargeable power PIN_L and the short-term chargeable power PIN_S by a predetermined ratio can be set as the chargeable power of the battery 40. This makes it possible to appropriately set the amount of charge that can be charged to the battery 40 in a short period of time based on the long-term chargeable power.

[0042] The low temperature upper limit SOC is a value indicating the upper limit SOC when the temperature of the battery 40 becomes low. Since the upper limit value of the SOC of the battery 40 is determined according to the battery temperature, the upper limit SOC when the battery 40 becomes a predetermined low temperature is also set in advance. Furthermore, the upper limit SOC that can realize the short-term chargeable power PIN_S is also set in advance according to the battery temperature. Since the chargeable power PIN decreases even if the SOC increases, low-power power generation control can be executed using the low temperature upper limit SOC so that the chargeable power PIN does not decrease too much.

[0043] [Example of torque and rotation speed calculation in low power generation control state] Here, an example of calculation of the rotation speed according to the rotation speed command to the engine controller 11 and the torque according to the torque command to the generator controller 21 in the low power generation control state will be described.

[0044] 5 is a flowchart showing an example of a control process in the control device 100 of the vehicle 1. This control process is executed by the vehicle controller 30 based on a program stored in a storage unit (not shown). This control process is also executed constantly at every control period.

[0045] In step S401, the vehicle controller 30 calculates the power required for the vehicle 1. This required power is the total value of the power required for the drive motor 50 and the power required for the auxiliary equipment 60. The power required for the drive motor 50 is calculated based on, for example, the depression amount of the accelerator pedal and the running state of the vehicle 1. Moreover, the power required for the auxiliary equipment 60 is calculated based on the total value of the power required by each device constituting the auxiliary equipment 60.

[0046] In step S402, the vehicle controller 30 calculates the torque required for power generation based on the power required for the vehicle 1 calculated in step S401 and the SOC of the battery 40. For example, when the SOC of the battery 40 is lower than a reference value, the torque required for power generation is calculated to generate more power than the reference power generation amount. On the other hand, when the SOC of the battery 40 is higher than the reference value, the torque required for power generation is calculated to generate less power than the reference power generation amount.

[0047] In addition, in the low power generation control state, the torque required for power generation is calculated so as to ensure power capable of continuing to charge the battery 40 within the chargeable power of the battery 40 calculated based on the short-term chargeable power PIN_S and the long-term chargeable power PIN_L. This prevents the SOC of the battery 40 from running out, and allows charging to be continued even when the vehicle 1 is stopped and other times when power consumption is low. In addition, the temperature of the battery 40 can be increased, allowing the battery 40 to quickly escape from a low chargeable power state caused by a low temperature.

[0048] In the low power generation control state, the torque required for power generation is calculated so as to charge the battery 40 so as not to exceed the low temperature upper limit SOC. This makes it possible to prevent a decrease in the chargeable power PIN due to an increase in the SOC of the battery 40.

[0049] In step S403, the vehicle controller 30 determines a target rotation speed and a target torque of the engine 10 based on the power generation torque calculated in step S402. A fixed value can be set as the target rotation speed in the low power generation control state, and this fixed value can be set appropriately based on experimental data, etc. For example, if the range of the rotation speed of the engine 10 in the normal power generation control state is from about 1400 rpm to about 6000 rpm, the target rotation speed can be set to a value of about 1400 rpm to 2200 rpm. The target torque is set to the same value as the power generation torque calculated in step S402.

[0050] In step S404, the vehicle controller 30 outputs the power generation required torque calculated in step S402 to the generator controller 21 as a torque command.

[0051] In step S405, the vehicle controller 30 outputs the target rotation speed and the target torque calculated in step S403 to the engine controller 11.

[0052] [Example of power generation control state transition] Here, in a low-temperature environment, it is often necessary to continue combustion for heating or to protect the engine 10. In addition, in such a low-temperature environment, when the temperature of the battery 40 is equal to or lower than a predetermined temperature, the chargeable power PIN of the battery 40 often becomes small. Therefore, when the temperature of the battery 40 is equal to or lower than the predetermined temperature, low-power power generation control is implemented. However, even in such a low-temperature environment, when the warm-up of the battery 40 is completed, the chargeable power PIN of the battery 40 becomes large. Therefore, whether or not low-power power generation control is required can be determined based on whether or not the warm-up of the battery 40 is completed. The predetermined temperature is a reference value when the implementation of the low-power power generation control is permitted, and can be appropriately set based on experimental data, etc.

[0053] However, even if the warm-up of the battery 40 is not complete, if the power required by the vehicle 1 is large, it is necessary to increase the amount of power generated by the generator 20 according to the required power. Therefore, in this embodiment, an example is shown in which it is determined whether or not low-power power generation control is required based on whether or not the warm-up of the battery 40 is complete and the required power of the vehicle 1.

[0054] [Example of control device operation] Fig. 6 is a flowchart showing an example of a control process in the control device 100 of the vehicle 1. This control process is executed by the vehicle controller 30 based on a program stored in a storage unit (not shown). This control process is constantly executed for each control period. This control process will be described with reference to Figs. 1 to 5 as appropriate.

[0055] In step S501, the vehicle controller 30 acquires from the battery controller 41 the battery warm-up determination flag, the short-term chargeable power PIN_S, the long-term chargeable power PIN_L, and the low temperature upper limit SOC as battery information.

[0056] In step S502, the vehicle controller 30 judges whether or not the warm-up judgment flag acquired in step S501 is on. If the warm-up of the battery 40 is completed, the warm-up judgment flag is turned on, and if the warm-up of the battery 40 is not completed, the warm-up judgment flag is turned off. That is, it is judged whether or not the warm-up of the battery 40 is completed. If the warm-up judgment flag is on, the process proceeds to step S505. On the other hand, if the warm-up judgment flag is off, the process proceeds to step S503. In this way, the vehicle controller 30 judges whether or not the warm-up of the battery 40 is completed based on the battery warm-up judgment flag as the state of the battery 40. Then, if the warm-up of the battery 40 is not completed, the vehicle controller 30 estimates that the temperature of the battery 40 is equal to or lower than a predetermined temperature.

[0057] In step S503, the vehicle controller 30 determines whether the electric power required by the vehicle is equal to or greater than a threshold value TH1. Here, the threshold value TH1 is a reference value for determining whether or not an electric power of a level required to perform normal power generation control is required, and can be set appropriately based on experimental data, etc. If the electric power required by the vehicle is equal to or greater than the threshold value TH1, the process proceeds to step S505. On the other hand, if the electric power required by the vehicle is less than the threshold value TH1, the process proceeds to step S504.

[0058] In this way, it is confirmed whether the warm-up of the battery 40 is complete, and if the warm-up of the battery 40 is complete, the normal power generation control state is set. On the other hand, only if the warm-up of the battery 40 is not complete and the temperature of the battery 40 is assumed to be low, is a transition to the low power generation control state permitted. However, even if the low power generation control is permitted, if the required power of the vehicle 1 is large, for example, when the vehicle 1 is traveling, the normal power generation control state is set.

[0059] In step S504, the vehicle controller 30 determines whether the short-term chargeable power PIN_S acquired in step S501 is equal to or greater than a threshold value TH2. Here, the threshold value TH2 is a reference value for determining whether or not to turn on the slow lamp when performing low-power power generation control, and can be set appropriately based on experimental data, etc. If the short-term chargeable power PIN_S is equal to or greater than the threshold value TH2, the process proceeds to step S506. On the other hand, if the short-term chargeable power PIN_S is less than the threshold value TH2, the process proceeds to step S507. The slow lamp is a vehicle driving performance degradation notification for notifying the driver that the driving performance of the vehicle 1 is deteriorating.

[0060] Here, the driving performance is degraded in the low power generation control state regardless of whether the vehicle 1 is stopped or running. In particular, when the short-term chargeable power PIN_S is less than the threshold value TH2, the torque command value for the generator 20 is low, so the amount of power generated by the generator 20 decreases, and the driving performance of the vehicle 1 is likely to degrade. Therefore, in such a state, the slow lamp is turned on to notify the occupants of the vehicle 1 that the driving performance is degraded.

[0061] In step S505, the vehicle controller 30 sets the power generation state of the engine 10 and the generator 20 to a normal power generation control state. In this case, the vehicle controller 30 executes the normal power generation control shown in FIG.

[0062] In step S506, the vehicle controller 30 sets the power generation state of the engine 10 and the generator 20 to a low-power power generation control state. In this case, the vehicle controller 30 executes the low-power power generation control shown in FIG.

[0063] In step S507, the vehicle controller 30 sets the power generation state of the engine 10 and the generator 20 to a low-power power generation control state, and turns on the slow lamp.

[0064] In this way, when low-power power generation control is permitted, if the short-term chargeable power PIN_S of the battery 40 is equal to or greater than the threshold TH2, the slow lamp is not turned on and the low-power power generation control state is established. On the other hand, if the short-term chargeable power PIN_S of the battery 40 is less than the threshold TH2, the slow lamp is turned on and the low-power power generation control state is established.

[0065] In this manner, in this embodiment, in order to minimize the time period during which the vehicle 1 transitions to the low-power generation control state in which the obtained power is small, the vehicle 1 can appropriately determine whether or not the low-power generation control state is required by using the required power of the vehicle 1 and the state of the battery 40. In this manner, by minimizing the time period during which the vehicle 1 is in the low-power generation control state, the occurrence frequency of a state in which the vehicle 1 is in a degraded state of driving performance can be reduced. In addition, the vehicle 1 is proactively set to the normal generation control state in situations in which the occupants of the vehicle 1 are unlikely to feel the increase in the rotation speed of the engine 10, for example, during acceleration. In this manner, the vehicle 1 can improve its driving performance by proactively setting the vehicle 1 to the normal generation control state in situations in which the occupants of the vehicle 1 are unlikely to feel the increase in the rotation speed of the engine 10.

[0066] In addition, even if the battery 40 warms up and reaches a state where the chargeable power PIN can be guaranteed to a certain extent from a state where low-power power generation control is unavoidable, the vehicle 1 may be transitioned to a low-power power generation control state while the vehicle 1 is stopped.

[0067] In this embodiment, in order to prevent the vehicle 1 from running out of power, the low-power power generation control performs power generation so as to ensure that the SOC of the battery 40 is sufficient, for example, so as not to fall below the SOC lower limit. However, this embodiment is not limited to this. For example, the low-power power generation control may be performed so as to charge the battery 40 to increase its SOC by several percent from the required SOC.

[0068] [Variation 1] The above describes an example in which low power generation control and normal power generation control are set based on the battery state, i.e., the battery temperature and the power required by the vehicle 1. Below, an example in which delay processing and restriction processing are executed in consideration of response delays of the engine 10 and the like in the low power generation control state is described as Modification 1.

[0069] [Torque and rotation speed control example] Fig. 7 is a diagram showing an example of setting the torque and rotation speed in a low power generation control state. The upper part of Fig. 7 shows an example of setting the torque of the generator 20, and the lower part of Fig. 7 shows an example of transition of the rotation speed of the engine 10. The horizontal axis shown at the top and bottom of Fig. 7 indicates the time axis. The vertical axis shown at the top of Fig. 7 indicates the torque value of the generator 20, and the vertical axis shown at the bottom of Fig. 7 indicates the rotation speed value of the engine 10.

[0070] The upper side of Fig. 7 shows a dotted straight line L2 indicating the target torque of the generator 20 and an upper limit value T2 of the target torque as a comparative example. In this case, the transition of the shaft torque of the actual engine 10 in response to the target torque (straight line L2) is a curve close to the curve C1. The lower side of Fig. 7 shows a dotted curve C12 indicating the transition of the rotation speed of the engine 10 corresponding to the transition of the shaft torque of the actual engine 10 in response to the target torque as a comparative example.

[0071] Also shown in the upper part of Fig. 7 are a straight line L1 indicating the target torque of the generator 20 set in the low-power power generation control state, an upper limit value T1 of the target torque of the generator 20 set in the low-power power generation control state, and a curve C1 indicating the transition of the actual shaft torque of the engine 10 in response to the target torque (straight line L1). Also shown in the lower part of Fig. 7 is a curve C11 indicating the transition of the rotation speed of the engine 10 corresponding to the curve C1.

[0072] Here, compared to the electrically controlled generator 20, the engine 10 can only generate torque during the combustion stroke, and due to a response delay in the amount of air, it is difficult for the engine 10 to respond to torque as quickly as the generator 20. For this reason, it is necessary to set the torque commanded to the generator 20 taking into consideration the response of the engine 10, etc.

[0073] Therefore, it is important to take into account the response delay of the engine 10 when calculating the command torque to be output to the generator 20. If the torque command for the generator 20 were set while ignoring the response delay of the engine 10, the torque generated by the generator 20 would become too large compared to the torque generated by the engine 10, causing a large drop in rotation speed and possibly causing the engine 10 to stall.

[0074] Therefore, in the first modification, a rate limit RL1 is set for the torque to be commanded to the generator 20. Also, a delay period D1 that delays the application of torque from the start timing of the engine 10, and an upper limit value T1 that limits the upper limit of the torque command are set. In this way, in the first modification, a rate limit function that sets a rate limit RL1 for the torque command, a delay timer function that delays the timing of the torque command to set the delay period D1, and a limit function that limits the upper limit of the torque command to the upper limit value T1 are provided. Note that, in the first modification, an example is shown in which the rate limit function, the delay timer function, and the limit function are provided, but at least one of these functions may be provided.

[0075] The delay period D1 can be set based on the water temperature of the engine 10. For example, a longer period can be set as the water temperature of the engine 10 decreases. The rate limit RL1 can be set to a constant value. The rate limit RL1 is a value that can mitigate sudden fluctuations in the torque of the engine 10, and can be set appropriately based on experimental data, etc. The upper limit value T1 can be set to the maximum torque that the engine 10 can exert in the low-power power generation control state.

[0076] Next, an example of setting the rate limit RL1, the delay period D1, and the upper limit value T1 will be described.

[0077] 8 is a flowchart showing an example of a control process in the control device 100 of the vehicle 1. This control process is executed by the vehicle controller 30 based on a program stored in a storage unit (not shown). This control process is also executed constantly at every control period.

[0078] In step S601, the vehicle controller 30 determines whether the water temperature of the engine 10 is equal to or lower than the water temperature threshold, and if the water temperature of the engine 10 is equal to or lower than the water temperature threshold, sets a delay period D1 according to the water temperature of the engine 10. In this way, if the water temperature of the engine 10 is equal to or lower than the water temperature threshold, the delay period D1 is set and the torque load on the engine 10 is put on hold for a predetermined time. Note that the water temperature of the engine 10 can be obtained from the engine controller 11 as a value obtained by a temperature sensor of the engine 10.

[0079] In step S602, the vehicle controller 30 determines whether to increase or decrease the torque of the generator 20, and if the torque of the generator 20 is to be increased or decreased, sets a rate limit RL1 during the period in which the torque is increased or decreased.

[0080] In step S603, the vehicle controller 30 sets the maximum torque value that the engine 10 can generate in the low power generation control state as an upper limit value T1.

[0081] In this way, when generating torque in the generator 20 in the low power generation control state with the same response speed as during normal power generation control, there is a concern that the engine may stall or the rotation may drop. For this reason, an upper limit value T1 of the maximum torque and a rate limit RL1 that alleviates the change in torque are provided. Also, in order to stabilize the combustion of the engine 10, a delay period D1 according to the water temperature of the engine 10 is provided. These can prevent engine stall or the rotation may drop. Also, by setting the rate limit RL1 and the upper limit value T1 when issuing a torque command, the rotation speed feedback of the engine 10 can be stably realized. As described above, at least one of the rate limit RL1, the delay period D1, and the upper limit value T1 may be set.

[0082] [Variation 2] In the second modification, an example is shown in which the rotation speed of the engine 10 is switched in accordance with the state of the vehicle 1, i.e., the vehicle speed, in the low power generation control state. Specifically, in the second modification, an example is shown in which the target rotation speed of the engine 10 is switched between two types of values ​​(LU1 and UR1 shown in Figs. 9 and 10).

[0083] [Example of controlling the rotation speed according to the vehicle speed] Figures 9 and 10 are diagrams showing an example of switching the rotation speed of the engine 10 depending on the vehicle speed of the vehicle 1 in a low power generation control state. Figure 9 shows an example of switching the rotation speed of the engine 10 when the vehicle speed V1 of the vehicle 1 increases, and Figure 10 shows an example of switching the rotation speed of the engine 10 when the vehicle speed V2 of the vehicle 1 decreases. The horizontal axis shown in Figures 9 and 10 indicates the time axis. The vertical axis shown in the upper part of Figures 9 and 10 indicates the value of the rotation speed of the engine 10, and the vertical axis shown in the lower part of Figures 9 and 10 indicates the value of the vehicle speed of the vehicle 1.

[0084] 9 and 10 show an example in which two types of rotational speeds UR1 and LR1 are set according to the state of the vehicle 1, i.e., the vehicle speed. The rotational speed UR1 is an example of a high rotational speed, and the rotational speed LR1 is an example of a low rotational speed. Here, it is preferable that the engine sound generated by the engine 10 is a sound that does not cause discomfort to the user of the vehicle 1. Therefore, when the vehicle 1 is stopped or when the vehicle 1 is moving at a low speed, i.e., when the vehicle speed is less than the threshold value TH3, the rotational speed LR1 is set. On the other hand, when the vehicle 1 is moving at a high speed, i.e., when the vehicle speed is equal to or greater than the threshold value TH3, the rotational speed UR1 is set. However, when the rotational speed LR1 is set, less power is obtained than when the rotational speed UR1 is set. Therefore, it is preferable that the two types of rotational speeds UR1 and LR1 are set in consideration of the discomfort expected to be given to the user of the vehicle 1 and the power required for the vehicle. The threshold value TH3 is a reference value when switching between the two types of rotational speeds UR1 and LR1, and can be set appropriately based on experimental data, etc., in consideration of the discomfort given to the user of the vehicle 1, the required power of the vehicle 1, etc.

[0085] In the second modification, two types of rotation speeds are switched depending on the required power and vehicle speed. For example, when the range of the rotation speed of the engine 10 in the normal power generation control state is from about 1400 rpm to about 6000 rpm, the values ​​of the two types of rotation speeds UR1 and LR1 can be set to values ​​within the range of about 1400 rpm to 2200 rpm. For example, the value of the rotation speed LR1 can be set to a low value within the range of 1400 rpm to 2200 rpm, and the value of the rotation speed UR1 can be set to a high value within the range of 1400 rpm to 2200 rpm.

[0086] Straight lines L21 and L31 indicate the target rotation speed of the engine 10, and curves C21 and C31 indicate the actual rotation speed of the engine 10. Straight lines L22 and L32 indicate the target rotation speed of the engine 10 as a comparative example, and curves C22 and C32 indicate the actual rotation speed of the engine 10 as a comparative example.

[0087] In the case where the engine 10 target speed is switched between two speeds UR1 and LR1 in the low power generation control state, if the engine speed is changed abruptly, there is a possibility that overshoot will be large during acceleration and undershoot will be large during deceleration, as shown in C22 in Fig. 9 and C32 in Fig. 10. Therefore, in order to prevent abrupt command when changing the speed, in Modification 2, change rates RL2 and RL3 are provided.

[0088] Here, an increase in the vehicle speed or required power of the vehicle 1 occurs when the driver of the vehicle 1 intends to drive or accelerate. In such a case, even if the rotation speed is increased and background noise increases, the passengers of the vehicle 1 do not feel uncomfortable. Therefore, the rotation speed can be switched according to the vehicle speed and the required power of the vehicle 1. In this way, by increasing the rotation speed of the engine 10 according to the driving request of the driver of the vehicle 1, the power obtained in the low power generation control state can be increased, and higher driving performance requirements can be met.

[0089] The two rotation speeds UR1 and LR1 may be switched based on conditions other than the vehicle speed. For example, if it is determined in step S504 (see FIG. 6) that the short-term chargeable power PIN_S is equal to or greater than the threshold value TH2, the rotation speed UR1 may be set in step S506. On the other hand, if it is determined that the short-term chargeable power PIN_S is less than the threshold value TH2, the rotation speed LR1 may be set in step S507. When the rotation speed LR1 is set, the slow lamp may be turned on or blinked. In addition, although the second modification shows an example in which two rotation speeds UR1 and LR1 are set and switched between, the present embodiment is also applicable to a case in which three or more rotation speeds are set and switched between based on the vehicle speed or the like.

[0090] [Configuration and Effects of This Embodiment] In the control method for the vehicle 1 according to the present embodiment, the control device 100 of the vehicle 1 includes a generator 20, an engine 10 connected to the generator 20, a drive motor 50 that drives the vehicle 1, and a battery 40 electrically connected to the generator 20 and the drive motor 50, and electric power generated by the generator 20 is supplied to at least one of the battery 40 and the drive motor 50. In this control method, in steps S401 to S405, S501 to S504, S506, and S507, if the temperature of the battery 40 is equal to or lower than a predetermined temperature, a required torque for power generation (an example of a drive torque target value) is calculated based on the required power of the vehicle 1 and the state of the battery 40, the generator 20 is torque-controlled based on the required torque for power generation, and the engine 10 is speed-controlled based on predetermined reference low-speed rotational speeds (e.g., rotational speeds UR1 and LR1), thereby executing low-power power generation control to generate electric power by the generator 20. For example, in low power generation control, torque control is performed to increase or decrease the torque of the generator 20 so that the required power generation torque is calculated based on the required power of the vehicle 1 and the state of the battery 40, and rotation speed control is performed to increase or decrease the rotation speed of the engine 10 so that the engine 10 reaches a predetermined reference low speed rotation speed.

[0091] According to this configuration, low-power power generation control can be executed even at low temperatures when the temperature of the battery 40 is below a predetermined temperature. This allows continuous charging to ensure the power required for the drive motor 50, the accessories 60, etc., thereby reducing the risk of running out of power.

[0092] In the control method for the vehicle 1 according to this embodiment, it is determined whether the warm-up of the battery 40 is complete based on the state of the battery 40, and if the warm-up of the battery 40 is not complete, it is estimated that the temperature of the battery 40 is equal to or lower than a predetermined temperature. Then, in steps S501 to S504, S506, and S507, if the warm-up of the battery 40 is not complete and the required power of the vehicle 1 is less than the threshold value TH1 (an example of a first threshold value), low-power power generation control is executed.

[0093] According to this configuration, when the warm-up of the battery 40 is not complete and the required power of the vehicle 1 is less than the threshold value TH1, low-power power generation control is executed, so that the battery 40 can be appropriately charged even at low temperatures.

[0094] In the control method for the vehicle 1 according to the present embodiment, in steps S401 to S405, S501 to S503, and S505, if the warm-up of the battery 40 has been completed or if the required power of the vehicle 1 is equal to or greater than the threshold value TH1 (an example of a first threshold value), a required power generation torque (an example of a drive torque target value) is calculated based on the required power generation of the vehicle 1 and the state of the battery 40, and the engine 10 is torque-controlled based on the required power generation torque, and the generator 20 is speed-controlled based on the speed based on the required power generation torque, thereby executing normal power generation control to generate power using the generator 20. For example, in the normal power generation control, torque control is executed to increase or decrease the torque of the engine 10 so that the required power generation torque is calculated based on the required power generation of the vehicle 1 and the state of the battery 40, and speed control is executed to increase or decrease the speed of the generator 20 so that the speed of the generator 20 is based on the required power generation torque.

[0095] According to this configuration, when the performance of the battery 40 has not deteriorated or when the power required by the vehicle 1 is relatively large, normal power generation control can be executed, thereby ensuring the power required for the drive motor 50, the auxiliary machinery 60, etc.

[0096] In the control method for the vehicle 1 according to this embodiment, in steps S506 and S507, in the low-power power generation control, torque control of the generator 20 and speed control of the engine 10 are executed based on the power generated by the generator 20 and the chargeable power PIN of the battery 40 corresponding to the temperature of the battery 40. For example, in the low-power power generation control, torque control of the generator 20 and speed control of the engine 10 are executed so that the power generated by the generator 20 is within the range of the chargeable power PIN of the battery 40 corresponding to the temperature of the battery 40.

[0097] According to this configuration, low-power power generation control is executed so that the power generated by the generator 20 falls within the range of the chargeable power PIN of the battery 40, so that appropriate power generation control according to the chargeable power PIN of the battery 40 can be realized. This makes it possible to prevent the SOC of the battery 40 from running out and to continue charging even when the vehicle 1 is stopped and other times when the power consumption of the vehicle 1 is low. In addition, the temperature of the battery 40 can be increased, and the battery 40 can be quickly released from a low chargeable power state caused by a low temperature.

[0098] In the control method for the vehicle 1 according to this embodiment, in steps S506 and S507, in the low-power power generation control, torque control of the generator 20 and speed control of the engine 10 are executed based on the power generated by the generator 20 and the upper limit SOC of the battery 40 determined according to the battery temperature. For example, in the low-power power generation control, torque control of the generator 20 and speed control of the engine 10 are executed so that the power generated by the generator 20 does not exceed the upper limit SOC of the battery 40 determined according to the battery temperature.

[0099] According to this configuration, low-power power generation control is executed so that the power generated by the generator 20 does not exceed the upper limit SOC of the battery 40, thereby realizing appropriate power generation control according to the upper limit SOC of the battery 40. Also, it is possible to prevent a decrease in the chargeable power PIN due to an increase in the SOC of the battery 40.

[0100] In the control method for the vehicle 1 according to this embodiment, in steps S506, S507, and S601 to S603, the low-power power generation control executes at least one of a delay process for delaying the torque control start timing of the generator 20, a torque limit process for limiting the maximum drive torque of the generator 20, and a limit process for limiting the rate of change when changing the drive torque of the generator 20. For example, as shown in Fig. 7, at least one of a delay process for setting a delay period D1, a torque limit process for setting an upper limit value T1, and a limit process for setting a rate limit RL1 can be executed.

[0101] According to this configuration, by executing each of these processes, it is possible to avoid a large change in the rotational speed of the engine 10 and engine stall in the low power generation control state.

[0102] In the control method for the vehicle 1 according to this embodiment, either a first low speed rotation speed LR1 or a second low speed rotation speed UR1 that is greater than the first low speed rotation speed LR1 is set as the reference low speed rotation speed, as shown in Figures 9 and 10. In steps S506 and S507, in the low power generation control, the rotation speed of the engine 10 is switched between the first low speed rotation speed LR1 and the second low speed rotation speed UR1 based on at least one of the required power of the vehicle 1 and the vehicle speed of the vehicle 1.

[0103] According to this configuration, the rotation speed of the engine 10 can be switched in response to the driving requirements of the driver of the vehicle 1, thereby adjusting the power obtained in the low power generation control state, thereby satisfying higher driving performance requirements.

[0104] In the control method for the vehicle 1 according to this embodiment, in steps S506 and S507, when the rotation speed of the engine 10 is switched, a change rate limiting process is executed to limit the rate of change of the rotation speed of the engine 10 between the first low rotation speed LR1 and the second low rotation speed UR1. For example, as shown in Fig. 9 and Fig. 10, a change rate limiting process can be executed to set change rates RL2 and RL3.

[0105] According to this configuration, when switching the rotation speed of the engine 10, the rate of change of the rotation speed is limited, so that abrupt rotation speed commands can be prevented, and overshoot or undershoot of the engine 10 can be avoided in a low-power power generation control state.

[0106] In the control method for the vehicle 1 according to this embodiment, in steps S504 and S507, in the low power generation control, if the short-term chargeable power PIN_S (an example of chargeable power) of the battery 40 according to the temperature of the battery 40 is less than the threshold value TH2 (an example of the second threshold value), a vehicle driving performance degradation notification process is executed to notify the occupant that the driving performance of the vehicle 1 will be degraded. As the vehicle driving performance degradation notification process, for example, a slow lamp can be turned on or flashed.

[0107] According to this configuration, it is possible to notify the driver that the driving performance of the vehicle 1 will be degraded due to the transition to the low power generation control state.

[0108] The control device 100 of the vehicle 1 is a vehicle control device that includes a generator 20, an engine 10 connected to the generator 20, a drive motor 50 that drives the vehicle 1, and a battery 40 that is electrically connected to the generator 20 and the drive motor 50, and in which power generated by the generator 20 is supplied to at least one of the battery 40 and the drive motor 50. The control device 100 includes a vehicle controller 30 (an example of a controller) that executes low-power power generation control to cause the generator 20 to generate power by calculating a required power generation torque (an example of a drive torque target value) based on the required power of the vehicle 1 and the state of the battery 40 when the temperature of the battery 40 is equal to or lower than a predetermined temperature, and controls the torque of the generator 20 based on the required power generation torque, and controls the rotation speed of the engine 10 based on predetermined reference low-speed rotation speeds (e.g., rotation speeds UR1 and LR1).

[0109] According to this configuration, low-power power generation control can be executed even at low temperatures when the temperature of the battery 40 is below a predetermined temperature. This allows continuous charging to ensure the power required for the drive motor 50, the accessories 60, etc., thereby reducing the risk of running out of power.

[0110] Note that each processing procedure shown in this embodiment is an example for realizing this embodiment, and the order of some of the processing procedures may be changed within the scope that allows the realization of this embodiment, and some of the processing procedures may be omitted or other processing procedures may be added.

[0111] Moreover, each process shown in this embodiment is executed based on a program for causing a computer to execute each processing procedure. Therefore, this embodiment can also be understood as an embodiment of a program that realizes the function of executing each process, and a recording medium that stores the program. For example, an update process for adding a new function to the control device can store the program in the storage device of the control device. This makes it possible to cause the updated control device to execute each process shown in this embodiment.

[0112] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

Claims

1. A method for controlling a vehicle including a generator, an engine connected to the generator, a drive motor for driving the vehicle, and a battery electrically connected to the generator and the drive motor, wherein electric power generated by the generator is supplied to at least one of the battery and the drive motor, comprising: Calculating a drive torque target value based on the required power of the vehicle and the state of the battery; determining whether the warm-up of the battery is completed based on the state of the battery; When the warm-up of the battery has not been completed and the required electric power of the vehicle is less than a first threshold value, a torque of the generator is controlled based on the drive torque target value, and a rotation speed of the engine is controlled based on a predetermined reference low speed rotation speed, thereby executing a low power generation control in which electric power is generated by the generator. How to control a vehicle.

2. A vehicle control method according to claim 1, comprising: When the warm-up of the battery has been completed, or when the required power of the vehicle is equal to or greater than the first threshold value, a drive torque target value is calculated based on the required power of the vehicle and the state of the battery, and the torque of the engine is controlled based on the drive torque target value, and a normal power generation control is executed to cause the generator to generate power by controlling the rotation speed of the generator based on the rotation speed based on the drive torque target value. How to control a vehicle.

3. A method for controlling a vehicle according to claim 1 or 2, comprising: In the low power generation control, a torque control of the generator and a rotation speed control of the engine are executed based on the power generated by the generator and a chargeable power of the battery according to a temperature of the battery. How to control a vehicle.

4. A method for controlling a vehicle according to any one of claims 1 to 3, comprising: In the low power generation control, a torque control of the generator and a rotation speed control of the engine are executed based on the power generated by the generator and an upper limit SOC of the battery determined according to a battery temperature. How to control a vehicle.

5. A method for controlling a vehicle according to any one of claims 1 to 4, comprising: In the low power power generation control, at least one of a delay process for delaying a torque control start timing of the generator, a torque limiting process for limiting a maximum driving torque of the generator, and a limiting process for limiting a rate of change when changing the driving torque of the generator is executed. How to control a vehicle.

6. A method for controlling a vehicle according to any one of claims 1 to 5, comprising: As the reference low speed rotation speed, one of a first low speed rotation speed and a second low speed rotation speed that is greater than the first low speed rotation speed is set, In the low power generation control, the engine speed is switched between the first low speed rotation speed and the second low speed rotation speed based on at least one of a required power of the vehicle and a vehicle speed of the vehicle. How to control a vehicle.

7. 7. A vehicle control method according to claim 6, comprising: When switching the engine speed, a change rate limiting process is executed to limit a change rate of the engine speed between the first low speed engine speed and the second low speed engine speed. How to control a vehicle.

8. A method for controlling a vehicle according to any one of claims 1 to 7, comprising: In the low power generation control, when the chargeable power of the battery according to the temperature of the battery is less than a second threshold, a vehicle driving performance degradation notification process is executed to notify an occupant that the driving performance of the vehicle will be reduced. How to control a vehicle.

9. A control device for a vehicle including a generator, an engine connected to the generator, a drive motor for driving a vehicle, and a battery electrically connected to the generator and the drive motor, wherein electric power generated by the generator is supplied to at least one of the battery and the drive motor, Calculating a drive torque target value based on the required power of the vehicle and the state of the battery; determining whether the warm-up of the battery is completed based on the state of the battery; and a controller that, when warming up of the battery has not been completed and the required power of the vehicle is less than a first threshold value, executes low-power power generation control to cause the generator to generate power by controlling the torque of the generator based on the drive torque target value and controlling the rotation speed of the engine based on a predetermined reference low-speed rotation speed. Vehicle control device.

10. A vehicle control method according to claim 1, comprising: the required electric power of the vehicle is a total value of electric power required for the drive motor and electric power required for auxiliary devices of the vehicle, and in the low-power power generation control, the drive torque target value is calculated within a range of chargeable electric power of the battery that is set based on a short-term chargeable electric power with which the battery can be charged in a short period of time and a long-term chargeable electric power with which the battery can be charged over a long period of time. How to control a vehicle.

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