Vehicle control method and vehicle control device

Abstract

A control method for a vehicle, the vehicle comprising: a generator; an engine connected to the generator; a drive motor that drives the vehicle; and a battery that is electrically connected to the generator and the drive motor, and supplies power generated by the generator to at least one of the battery and the drive motor. In the control method, when the temperature of the battery is less than or equal to a predetermined temperature, a drive torque target value is calculated based on the requested power of the vehicle and the state of the battery, the generator is torque-controlled based on the drive torque target value, and the engine speed is controlled based on a predetermined reference low speed, thereby executing low power generation control using power generated by the generator.

Description

Technical Field

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

[0002] JP2004-300957A discloses a technique for performing feedback control so that the engine speed reaches a target speed when the engine is idling. In this technique, a generator is connected to the output shaft of the engine, and the generator is controlled so that the torque generated by the engine is absorbed if the actual engine speed is greater than the target speed, and the generator is controlled so that the torque is applied to the engine if the actual engine speed is less than the target speed. Summary of the invention

[0003] In the above-mentioned prior art, even when the engine speed fluctuates due to load or the like when the engine is idling, the engine speed can be converged to the target idle speed. However, in a series hybrid vehicle that is configured to charge a battery by driving a generator with an engine, the engine is idled when the engine and battery are warmed up, and the battery is not charged in this case. 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 and the battery is not charged for a long time, the SOC of the battery may continue to decrease due to the power consumption of the vehicle drive, auxiliary machines, etc.

[0004] An object of the present invention is to ensure the electric power required for driving a vehicle and operating auxiliary machines and to reduce the risk of power shortage in the vehicle.

[0005] One embodiment of the present invention is a control method for a vehicle including: a generator; an engine connected to the generator; a drive motor that drives the vehicle; and

[0006] The battery is electrically connected to the generator and the drive motor, and supplies the power generated by the generator to at least one of the battery and the drive motor. In the control method, when the temperature of the battery is less than or equal to a predetermined temperature, a drive torque target value is calculated based on the requested power of the vehicle and the state of the battery, the torque of the generator is controlled based on the drive torque target value, and the speed of the engine is controlled based on a predetermined reference low speed, thereby executing low power generation control using the power generated by the generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A diagram showing a schematic configuration of a vehicle.

[0008] Figure 2It is a block diagram schematically showing a configuration example of a vehicle control device.

[0009] Figure 3 It is a block diagram schematically showing a configuration example of a control device for a vehicle of a comparative example.

[0010] Figure 4 It is a block diagram schematically showing a configuration example of a vehicle control device.

[0011] Figure 5 This is a flowchart showing an example of control processing by the vehicle control device.

[0012] Figure 6 This is a flowchart showing an example of control processing by the vehicle control device.

[0013] Figure 7 This is a diagram showing a setting example when setting the torque and the rotation speed in the low power generation control state.

[0014] Figure 8 This is a flowchart showing an example of control processing by the vehicle control device.

[0015] Fig. 9 This is a diagram showing a switching example when the engine speed is switched according to the vehicle speed in the low power generation control state.

[0016] Fig.10 This is a diagram showing a switching example when the engine speed is switched according to the vehicle speed in the low power generation control state. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0018] [Example of vehicle structure]

[0019] Figure 1 1 is a diagram showing a schematic configuration diagram of a vehicle 1. The vehicle 1 is a series hybrid vehicle, and in this embodiment, a power generation control system of the series hybrid vehicle will be mainly described.

[0020] The vehicle 1 includes an engine 10, a generator 20, a battery 40, a drive motor 50, auxiliary machines 60, a gear 71, and drive wheels 72. The engine 10 drives the generator 20 to generate electricity, and the drive motor 50 is driven by the electricity generated by the generator 20.

[0021] The engine 10 is an internal combustion engine, for example, a gasoline engine. The engine 10 is connected to the generator 20 in a manner capable of transmitting power. The generator 20 is an electric generator, which performs electric operation (motoring) of the engine 10 in addition to generating electricity. The electric operation is performed by driving the engine 10 in a stopped state using the generator 20. The drive motor 50 is an electric generator, which generates a driving force for the vehicle 1. The driving force generated by the drive motor 50 is transmitted to the drive wheel 72 via the gear 71 as a reduction gear. The drive motor 50 also regenerates energy by being driven by the power from the drive wheel 72. The energy regenerated as electricity by the drive motor 50 can charge the battery 40.

[0022] The battery 40 stores the electric power generated by the generator 20 and the electric power regenerated by the drive motor 50. As the battery 40, for example, a lithium-ion secondary battery can be used. A discharge request SOC (State Of Charge) is set for the battery 40. SOC is a parameter indicating the state of charge of the battery 40, and the discharge request SOC is preset as a value for specifying the full charge of the battery 40. In other words, the full charge of the battery 40 is specified by the discharge request SOC, and for example, when the SOC as the charging rate is 90%, it is set to be fully charged.

[0023] In the power generation control system shown in this embodiment, the drive wheels 72 and the engine 10 are provided independently, and the engine 10 is connected only to the generator 20. In addition, the engine 10 and the generator 20 function as a power generation unit and constitute a power generation system.

[0024] The auxiliary devices 60 are devices installed in the vehicle 1 and require electric power. For example, the auxiliary devices 60 are vehicle lights, speakers, a car navigation device, an air conditioner, and the like.

[0025] The vehicle 1 also has 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 in a manner that allows them to communicate with each other. The vehicle controller 30 is composed of one or more microcomputers having 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). With respect to the vehicle controller 30, various controls are performed by using the CPU to execute programs 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.

[0026] The generator controller 21 controls the generator 20. The generator controller 21 further includes a first inverter as an inverter for the generator 20. The first inverter may have a different structure from the generator controller 21. The generator controller 21 controls the generator 20 by controlling the first inverter.

[0027] The drive motor controller 51 controls the drive motor 50. The drive motor controller 51 further includes a second inverter as an inverter for the drive motor 50. The second inverter may have a different structure from the drive motor controller 51. The drive motor controller 51 controls the drive motor 50 by controlling the second inverter.

[0028] 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. Thus, the power generated by the generator 20 charges the battery 40. The first inverter also converts the DC current supplied from the battery 40 into an AC current and supplies it to the generator 20. Thus, the generator 20 is driven by the power of the battery 40. Signals such as current, voltage, and SOC are also input from the generator 20, the drive motor 50, and the battery 40 to the generator controller 21. In addition, the relationship between the second inverter, the drive motor 50, and the battery 40 is the same.

[0029] The engine controller 11 controls the engine 10 . For example, the engine controller 11 controls the throttle valve, the fuel injection valve, the spark plug, etc., and adjusts the intake amount, the injection amount, the ignition timing, etc. to perform engine control. In addition, the engine control signal can be further input to the vehicle controller 30 via the engine controller 11 .

[0030] The vehicle controller 30 centrally controls the engine 10 , the generator 20 , the battery 40 , the drive motor 50 , etc. The vehicle controller 30 receives signals from an accelerator opening sensor 91 for detecting an accelerator opening APO and a shift position sensor 92 for detecting a shift lever position (shift position) selected by a driver's operation.

[0031] [Configuration example of control device]

[0032] Figure 2 and Figure 4 1 is a block diagram schematically showing a configuration example of the control device 100 of the vehicle 1 . Figure 3 1 is a block diagram schematically showing a configuration example of a control device for a comparative vehicle. The control device 100 of the vehicle 1 is a device for executing power generation control of the vehicle 1, and includes an engine 10, a generator 20, a battery 40, etc. Figures 2 to 4 2 shows an example of the relationship between power generation control and engine control in a vehicle.

[0033] exist Figure 2 An example of the relationship under normal power generation control is shown in Figure 3 The relationship example in the E-ISC (Engine-Idle Speed ​​Control) state as a comparative example is shown in FIG. Figure 4 2 shows an example of the relationship in the low power generation control state.

[0034] In the vehicle 1, the power generated by the generator 20 is supplied to the battery 40, the drive motor 50, or the auxiliary machines 60. The drive motor 50 and the auxiliary machines 60 are supplied with the total value of the power generated by the generator 20 and the power of the battery 40.

[0035] [Normal power generation control example]

[0036] like Figure 2 As shown, in the normal power generation control state, the vehicle controller 30 outputs a torque command to the engine controller 11 and outputs a speed command to the generator controller 21. That is, in the normal power generation control state, the speed command is output to the generator 20 side in consideration of the speed controllability (response speed, accuracy), and the torque command is output to the engine 10 side. In this case, on the generator 20 side, feedback control of the speed based on the target speed and the actual speed, such as PID control and speed servo control, is performed in a manner to achieve the target speed corresponding to the speed command. In addition, the actual speed of the generator 20 can be detected by a speed sensor, such as a rotation phase angle sensor such as a resolver. As a result, the generator 20 controls the speed of the engine 10, and the engine 10 generates the torque required for power generation.

[0037] like Figure 2 As shown, in the normal power generation control state, the speed of the engine 10 is maintained by generating a speed maintenance torque by the generator 20. In addition, if the shaft torque of the engine 10 is used as a reference, it is also possible to consider setting the speed maintenance torque to a negative torque, friction torque, etc. Specifically, the generator controller 21 performs switching control of the first inverter in a manner to achieve a target speed corresponding to the speed command output from the vehicle controller 30. That is, through the switching control of the first inverter, the generator 20 applies the speed maintenance torque to the engine 10. For example, when the speed of the generator 20 connected to the engine 10 is greater than the target speed, the speed maintenance torque is applied in a manner to reduce the speed of the generator 20 and suppress the rotation of the engine 10. On the other hand, when the speed of the generator 20 connected to the engine 10 is less than the target speed, the speed maintenance torque of the generator 20 is reduced.

[0038] Thus, in the normal power generation control state, the torque control of increasing or decreasing the torque of the engine 10 is performed so as to achieve the torque required for power generation, and the speed control of increasing or decreasing the speed of the generator 20 is performed so as to achieve the 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 speed, thereby maintaining the speed of the engine 10 and generating power. In addition, the value obtained by multiplying the product of the torque generated by the generator 20 and the speed of the generator 20 by a coefficient becomes the value of the power generated by the generator 20.

[0039] In addition, the engine 10 often has a property of fluctuating with respect to the torque command value, and generates a torque with a value larger than the torque command value. In addition, it is known that the battery 40 has a property of decreasing the chargeable power PIN in a low temperature environment.

[0040] If the rechargeable power PIN of the battery 40 is reduced at low temperatures, the torque of the engine 10 is also set to be small. If the torque of the engine 10 fluctuates greatly in this state, the torque fluctuation cannot be absorbed on the generator 20 side, and overspeed (racing) occurs in the engine 10. It is also conceivable that in this state, that is, in a state where the rechargeable power PIN is small and the fluctuation of the engine torque cannot be absorbed, the engine 10 itself is set to the E-ISC (Engine-Idle Speed ​​Control) state for implementing speed control. Therefore, as a comparative example of this embodiment, in Figure 3 An example of implementing E-ISC is shown in FIG.

[0041] [E-ISC as a comparative example]

[0042] like Figure 3 As shown, 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 the switch control to the generator controller 21 so as not to perform the switch control. In this way, the idle speed command is output to the engine controller 11 and the engine 10 is controlled to the idle speed, so that the occurrence of over-speed operation can be suppressed. In this case, the switch control of the first inverter of the generator 20 is not performed, so no output is made from the battery 40 to the first inverter, and no power is generated from the generator 20.

[0043] Thus, in the E-ISC state, the engine 10 is operated at the idle speed and the generator 20 is set to the no-load state. Therefore, the battery 40 is in a state of only discharge, and the SOC of the battery 40 continues to decrease.

[0044] In particular, in a low temperature environment where the chargeable power PIN of the battery 40 is reduced, if E-ISC is performed for a long time, the battery 40 may be short of power due to power consumption of the drive motor 50 and auxiliary machines 60 of the vehicle 1 if the battery 40 is not charged for a long time.

[0045] Therefore, in the present embodiment, even in the case where the rechargeable power PIN is reduced in a low temperature environment, the risk of power shortage of the vehicle 1 is reduced, and thus low power generation in the generator 20 is performed while the engine 10 is controlled to perform speed control. That is, in the present embodiment, in the case where the rechargeable power PIN is reduced in a low temperature environment, low power generation is performed so as not to be lower than the required amount of SOC of the battery 40, for example, the SOC lower limit value, so as to ensure that the required amount of SOC of the battery 40 is ensured. Figure 4 The low power generation control example is shown in FIG. In addition, the low power generation control state is also called the load ISC (Idle Speed ​​Control) state because the engine 10 is rotated by speed control and the generator 20 is torque controlled to generate power. In addition, in the present embodiment, the normal power generation control (see FIG. 1 ) is changed according to the state of the battery 40 and the state of the vehicle. Figure 2 ) and low power generation control (refer to Figure 4 ) is switched to ensure the minimum driving performance of the vehicle 1 and prevent the SOC of the battery 40 from being depleted.

[0046] [Low power generation control example]

[0047] like Figure 4 As shown, 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 corresponding to the state of the battery 40, such as the chargeable power PIN, to the generator controller 21. That is, in the low power generation control state, the torque command is implemented for the generator 20, so that the generated power can be obtained in the rotation control based on the engine 10. As a result, the rapid increase in the rotation speed of the engine 10 and the risk of power shortage of the battery 40 can be suppressed.

[0048] In addition, the engine controller 11 performs speed control based on the speed of the engine 10 detected by a speed detection sensor, such as a crank angle sensor. That is, the engine controller 11 calculates the difference between the detection value of the speed detection sensor and the target value corresponding to the speed command, and adjusts the air volume, fuel injection, throttle valve opening, ignition timing, etc. based on the difference to perform speed control. The speed maintenance torque is output from the engine 10 side by the execution of this speed control. In this way, in the low-power power generation control, the torque control of increasing or decreasing the torque of the generator 20 is performed in a manner to achieve the torque required for power generation, and the speed control of increasing or decreasing the speed of the engine 10 is performed in a manner to make the engine 10 reach a specified reference low speed.

[0049] As described above, in the low power generation control state, the generator 20 generates torque and the engine 10 is slowed down at a predetermined low speed. Therefore, if a torque command is set for the generator 20 without considering the response delay of the engine 10, the engine 10 may stall.

[0050] Therefore, when the vehicle controller 30 outputs a torque command to the generator 20, it is preferable to notify the engine controller 11 in advance of a value identical to the torque command as a target torque. Thus, when torque is applied from the generator 20 to the engine 10, the reference torque at the time of the rotation speed feedback of the engine 10 can be corrected based on the target torque.

[0051] In this way, when calculating the torque corresponding to the electric power to be generated, a torque command is issued to the generator 20 and the generated torque, that is, the target torque is output to the engine 10. This improves the controllability of the rotation speed feedback.

[0052] In addition, the vehicle controller 30 acquires battery information related to the battery 40 from the battery controller 41. The battery information includes a battery warm-up determination flag, short-term chargeable power PIN_S, long-term chargeable power PIN_L, and a low-temperature upper limit SOC.

[0053] Here, the battery warm-up determination flag is a flag indicating whether the battery warm-up is completed. Specifically, when the battery warm-up determination flag is ON, it indicates that the battery warm-up is completed, and when the battery warm-up determination flag is OFF, it indicates that the battery warm-up is not completed. In addition, with respect to the battery controller 41, when the cell temperature of the battery 40 is greater than or equal to the temperature threshold, ON is output to the vehicle controller 30 as a battery warm-up determination flag, and when the cell temperature of the battery 40 is less than the temperature threshold, OFF is output to the vehicle controller 30 as a battery warm-up determination flag. The temperature threshold is a value of the temperature that can determine the degree to which the performance of the battery 40 can be exerted, and can be appropriately set based on experimental data, etc. In addition, the battery controller 41 can determine whether the cell temperature of the battery 40 is less than or equal to the temperature threshold based on the voltage of the battery 40, etc.

[0054] In addition, the rechargeable power PIN is information indicating the value of the power that can be charged in the battery 40. In addition, the short-term rechargeable power PIN_S is the power that can charge the battery 40 in a short period of time. The short-term rechargeable power PIN_S is equivalent to the power generated by the rapid increase in the engine speed after the engine 10 is started, or the power that can absorb the regenerative charging power during the vehicle driving (especially at high speed). In addition, the time for determining the short-term rechargeable power PIN_S is in the range of several seconds to less than or equal to tens of seconds, and is determined by the time from the start of the engine to the rapid increase in the engine speed, and / or the time for the battery 40 to absorb the large regenerative power generated when the vehicle decelerates, etc., and is at least shorter than the range of the time for determining the long-term rechargeable power PIN_L described later. In addition, the battery controller 41 calculates the short-term rechargeable power PIN_S based on the SOC of the battery 40 and the temperature of the battery 40 (battery temperature).

[0055] In addition, the long-term rechargeable power PIN_L is power that can charge the battery 40 in a long period of time. The long-term rechargeable power PIN_L is equivalent to the rechargeable power required to complete the warm-up of the battery 40 by charging. In addition, the time for determining the long-term rechargeable power is a time in the range of several hundred seconds to several tens of minutes. In addition, the battery controller 41 calculates the long-term rechargeable power PIN_L based on the SOC of the battery 40 and the temperature of the battery 40. In this way, the long-term rechargeable power PIN_L means power that can stably and continuously charge the battery 40. In addition, the long-term rechargeable power PIN_L acts as a rechargeable power PIN at low temperature based on a long-term second value that can be continuously used. In addition, the short-term rechargeable power is also called instantaneous rechargeable power, and the long-term rechargeable power is also called continuous rechargeable power.

[0056] In addition, the voltage and temperature of the battery 40 can be measured to obtain the chargeable power PIN. In addition, the voltage, current and temperature of the battery 40 can also be measured to obtain the chargeable power PIN. In addition, the chargeable power of the battery 40 can 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 degree of charge. Therefore, for example, the value obtained by multiplying the 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. In this way, the charge amount that can be charged to the battery 40 in a short period of time can be appropriately set based on the long-term chargeable power.

[0057] In addition, the upper limit SOC at low temperature is a value indicating the upper limit SOC when the temperature of the battery 40 is low. In addition, the upper limit value of the SOC of the battery 40 is specified according to the battery temperature, so the upper limit SOC when the battery 40 reaches a specified low temperature is also preset. In addition, the SOC that can achieve the upper limit of the short-term chargeable power PIN_S is also preset according to the battery temperature. In addition, even if the SOC increases, the chargeable power PIN is also reduced, so it is possible to perform low power generation control by using the upper limit SOC at low temperature in a manner that the chargeable power PIN is not excessively reduced.

[0058] [Calculation example of torque and speed in low power generation control state]

[0059] Here, a calculation example of the rotation speed corresponding to the rotation speed command to the engine controller 11 and the torque corresponding to the torque command to the generator controller 21 in the low power generation control state will be described.

[0060] Figure 5 1 is a flowchart showing an example of a control process of the control device 100 of the vehicle 1. The control process is executed by the vehicle controller 30 based on a program stored in a storage unit (not shown). The control process is always executed in each control cycle.

[0061] In step S401, the vehicle controller 30 calculates the required power of the vehicle 1. The required power is the total value of the power required for the drive motor 50 and the power required for the auxiliary machines 60. The power required for the drive motor 50 is calculated based on, for example, the amount of depression of the accelerator pedal, the running state of the vehicle 1, etc. In addition, the power required for the auxiliary machines 60 is calculated based on the total value of the power required in each device constituting the auxiliary machines 60.

[0062] In step S402, the vehicle controller 30 calculates the torque required for power generation based on the required power of 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 the reference value, the torque required for power generation is calculated to set the power generation amount to be greater 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 set the power generation amount to be less than the reference power generation amount.

[0063] In addition, in the low power generation control state, the torque required for power generation is calculated in such a way that the power that can continuously 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 is ensured. In this way, the SOC of the battery 40 can be prevented from being depleted, and charging can be continued even when the vehicle 1 is parked with low power consumption. In addition, the temperature of the battery 40 can be increased, and the low chargeable power state due to low temperature can be exited in advance.

[0064] In the low power generation control state, the power generation required torque is calculated so as not to exceed the low temperature upper limit SOC and to charge the battery 40. This can prevent the chargeable power PIN from decreasing due to an increase in the SOC of the battery 40.

[0065] In step S403, the vehicle controller 30 obtains the target speed and target torque of the engine 10 based on the torque required for power generation calculated in step S402. In addition, a fixed value can be set as the target speed in the low power generation control state, and the fixed value can be appropriately set based on experimental data, etc. For example, when the speed of the engine 10 in the normal power generation control state ranges from about 1400 rpm to about 6000 rpm, the target speed can be set to a value of about 1400 rpm to 2200 rpm. In addition, the target torque is set to the same value as the value of the torque required for power generation calculated in step S402.

[0066] 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.

[0067] In step S405 , the vehicle controller 30 outputs the target rotation speed and target torque obtained in step S403 to the engine controller 11 .

[0068] [Example of Transition of Power Generation Control State]

[0069] Here, in a low temperature environment, continuous combustion is mostly required for heating and protection of the engine 10. In addition, in such a low temperature environment, when the temperature of the battery 40 is less than or equal to the specified temperature, the rechargeable power PIN of the battery 40 is mostly reduced. Therefore, when the temperature of the battery 40 is less than or equal to the specified temperature, low power generation control is implemented. However, even in such a low temperature environment, when the warm-up of the battery 40 is completed, the rechargeable power PIN of the battery 40 also increases. Therefore, it is possible to determine whether low power generation control is needed based on whether the warm-up of the battery 40 is completed. In addition, the specified temperature is a reference value for allowing the implementation of low power generation control, and can be appropriately set based on experimental data, etc.

[0070] However, even when the battery 40 is not fully warmed up, if the power required by the vehicle 1 is large, it is necessary to increase the power generated by the generator 20 according to the power required. Therefore, in this embodiment, an example is shown in which whether low power generation control is required is determined based on whether the battery 40 is fully warmed up and the power required by the vehicle 1.

[0071] [Operation example of control device]

[0072] Figure 6 1 is a flowchart showing an example of a control process of the control device 100 of the vehicle 1. The control process is executed by the vehicle controller 30 based on a program stored in a storage unit (not shown). The control process is always executed in each control cycle. Figures 1 to 5 Provide explanation.

[0073] In step S501 , the vehicle controller 30 acquires 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 from the battery controller 41 as battery information.

[0074] In step S502, the vehicle controller 30 determines whether the warm-up determination flag obtained in step S501 is ON. In addition, when the warm-up of the battery 40 is completed, the warm-up determination flag is set to ON, and when the warm-up of the battery 40 is not completed, the warm-up determination flag is set to OFF. That is, it is determined whether the warm-up of the battery 40 is completed. When the warm-up determination flag is ON, the process proceeds to step S505. On the other hand, when the warm-up determination flag is OFF, the process proceeds to step S503. In this way, the vehicle controller 30 determines whether the warm-up of the battery 40 is completed based on the battery warm-up determination flag which is the state of the battery 40. Moreover, when the warm-up of the battery 40 is not completed, the vehicle controller 30 estimates that the temperature of the battery 40 is less than or equal to the specified temperature.

[0075] In step S503, the vehicle controller 30 determines whether the vehicle requested power is greater than or equal to the threshold TH1. Here, the threshold TH1 is a reference value for determining whether the power required to implement normal power generation control is required, and can be appropriately set based on experimental data, etc. If the vehicle requested power is greater than or equal to the threshold TH1, the process proceeds to step S505. On the other hand, if the vehicle requested power is less than the threshold TH1, the process proceeds to step S504.

[0076] In this way, it is confirmed whether the warm-up of the battery 40 is completed, and when the warm-up of the battery 40 is completed, the normal power generation control state is set. On the other hand, only when the warm-up of the battery 40 is not completed and it is assumed that the temperature of the battery 40 is low, the transition to the low power generation control state is permitted. However, even when the low power generation control is permitted, when 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.

[0077] In step S504, the vehicle controller 30 determines whether the short-term rechargeable power PIN_S acquired in step S501 is greater than or equal to the threshold value TH2. Here, the threshold value TH2 is a reference value for determining whether to light the slow lamp when implementing low power generation control, and can be appropriately set based on experimental data, etc. In the case where the short-term rechargeable power PIN_S is greater than or equal to the threshold value TH2, the process proceeds to step S506. On the other hand, in the case where the short-term rechargeable power PIN_S is less than the threshold value TH2, the process proceeds to step S507. In addition, the slow lamp is a vehicle driving performance degradation notification for notifying the driver that the driving performance of the vehicle 1 has deteriorated.

[0078] Here, regardless of whether the vehicle 1 is parked or traveling, the driving performance is reduced in the low power generation control state. In particular, when the short-term chargeable power PIN_S is less than the threshold TH2, the value of the torque command for the generator 20 is reduced, so the power generation amount based on the generator 20 is reduced, and the driving performance of the vehicle 1 is easily reduced. Therefore, in this state, the slow running lamp is turned on to notify the occupants of the vehicle 1 that the driving performance is in a state where it has been reduced.

[0079] In step S505, the vehicle controller 30 sets the power generation state by the engine 10 and the generator 20 to the normal power generation control state. In this case, the vehicle controller 30 executes Figure 2 Typical power generation control shown.

[0080] In step S506, the vehicle controller 30 sets the power generation state by the engine 10 and the generator 20 to the low power generation control state. In this case, the vehicle controller 30 executes Figure 4 Low power generation control shown.

[0081] In step S507 , the vehicle controller 30 sets the power generation state by the engine 10 and the generator 20 to the low power generation control state, and turns on the slow running lamp.

[0082] Thus, when the low power generation control is permitted, if the short-term chargeable power PIN_S of the battery 40 is greater than or equal to the threshold TH2, the slow-moving lamp is not turned on and the low power generation control state is set. On the other hand, when the short-term chargeable power PIN_S of the battery 40 is less than the threshold TH2, the slow-moving lamp is turned on and the low power generation control state is set.

[0083] Thus, in the present embodiment, the time period for transitioning to the low power generation control state in which the obtained power is reduced is minimized, so that it is possible to appropriately determine whether the low power generation control state is necessary by using the requested power of the vehicle 1 and the state of the battery 40. Thus, the frequency of occurrence of a state in which the driving performance of the vehicle 1 is reduced can be reduced by minimizing the time period for setting the low power generation control state. In addition, in a situation where the occupants of the vehicle 1 are not likely to feel a sudden increase in the speed of the engine 10, such as during acceleration, the normal power generation control state is actively set. Thus, in a situation where the sudden increase in the speed of the engine 10 is not likely to be felt, the driving performance can be improved by actively setting the normal power generation control state.

[0084] Even when the battery 40 is warmed up from the state in which the low power generation control has to be implemented and the chargeable power PIN can be secured to a certain extent, the vehicle 1 can be shifted to the low power generation control state while it is parked.

[0085] In addition, in the present embodiment, in order to prevent the vehicle 1 from running out of power, the low power generation control is performed so that the required amount of SOC of the battery 40, for example, the SOC lower limit value, is not lowered, and an example of ensuring the required amount of SOC of the battery 40 is shown. However, the present embodiment is not limited to this. For example, the low power generation control may be performed in a manner that charging is increased by a few percent relative to the required amount of SOC of the battery 40.

[0086] [Modification 1]

[0087] In the above, an example of setting low power generation control and normal power generation control based on the battery state, that is, the battery temperature and the requested power of the vehicle 1 is shown. Next, as a modification 1, an example of performing delay processing and restriction processing in the low power generation control state in consideration of the response lag of the engine 10 is shown.

[0088] [Torque and speed control example]

[0089] Figure 71 is a diagram showing an example of setting the torque and the rotation speed in a low power generation control state. Figure 7 The upper side of FIG. 1 shows an example of setting the torque of the generator 20. Figure 7 The lower side of shows an example of the transition of the rotation speed of the engine 10. Figure 7 The horizontal axis shown above and below represents the time axis. Figure 7 The vertical axis shown on the upper side of represents the value of the torque of the generator 20. Figure 7 The vertical axis shown below represents the value of the rotation speed of the engine 10 .

[0090] exist Figure 7 As a comparison, a dashed straight line L2 representing the target torque of the generator 20 and an upper limit value T2 of the target torque are shown on the upper side. In this case, the actual shaft torque of the engine 10 in response to the target torque (straight line L2) becomes a curve close to the curve C1. Figure 7 A dashed curve C12 showing a transition of the rotation speed of the engine 10 corresponding to a transition of the actual shaft torque of the engine 10 in response to the target torque is shown below as a comparative example.

[0091] In addition, Figure 7 On the upper side of , there are shown a straight line L1 indicating the target torque of the generator 20 set in the low power generation control state, an upper limit value T1 of the target torque of the generator 20 set in the low power generation control state, and a curve C1 indicating the transition of the shaft torque of the actual engine 10 in response to the target torque (straight line L1). Figure 7 A curve C11 indicating the transition of the rotation speed of the engine 10 corresponding to the curve C1 is shown below the curve C1.

[0092] Here, for the generator 20 controlled by power, it is difficult for the engine 10 to generate torque only in the combustion stroke and to respond as quickly as the generator 20 due to the response lag of the air amount. Therefore, the torque instructed to the generator 20 needs to be set in consideration of the responsiveness of the engine 10.

[0093] Therefore, when calculating the command torque output to the generator 20, it is important to consider the response lag of the engine 10. If the response lag of the engine 10 is ignored and the torque command of the generator 20 is set, the torque generated by the generator 20 is excessively greater than the torque generated by the engine 10, causing the rotation speed to drop significantly, and the engine 10 may stall depending on the situation.

[0094] Therefore, in Modification 1, a rate limit RL1 is set for the torque indicated to the generator 20. In addition, a lag period D1 for delaying the application of the torque relative to the start timing of the engine 10 and an upper limit value T1 for limiting the upper limit of the torque command are set. In this way, in Modification 1, the following functions are provided: a rate limit function for setting a rate limit RL1 for the torque command, a lag timer function for delaying the timing of the torque command and setting the lag period D1, and a limit function for limiting the upper limit of the torque command to the upper limit value T1. In addition, in Modification 1, an example of providing a rate limit function, a lag timer function, and a limit function is shown, but at least one of these functions may be provided.

[0095] In addition, the lag period D1 can be set based on the water temperature of the engine 10. For example, a longer period can be set corresponding to the case where the water temperature of the engine 10 decreases. In addition, the rate limit RL1 can be set to a constant value. In addition, the rate limit RL1 is a value that can alleviate the rapid change of the torque of the engine 10, and can be appropriately set based on experimental data, etc. In addition, the upper limit value T1 can be set to the value of the maximum torque that the engine 10 can exert in the low power generation control state.

[0096] Next, a setting example of the rate limit RL1 , the hysteresis period D1 , and the upper limit value T1 will be described.

[0097] Figure 8 1 is a flowchart showing an example of the control process of the control device 100 of the vehicle 1. The control process is executed by the vehicle controller 30 based on a program stored in a storage unit (not shown). The control process is always executed in each control cycle.

[0098] In step S601, the vehicle controller 30 determines whether the water temperature of the engine 10 is less than or equal to the water temperature threshold value, and when the water temperature of the engine 10 is less than or equal to the water temperature threshold value, the hysteresis period D1 is set according to the water temperature of the engine 10. In this way, when the water temperature of the engine 10 is less than or equal to the water temperature threshold value, the hysteresis period D1 is set to wait for a predetermined time for the torque load on the engine 10. In addition, regarding the water temperature of the engine 10, the value obtained by the temperature sensor of the engine 10 can be obtained from the engine controller 11.

[0099] In step S602 , the vehicle controller 30 determines whether the torque of the generator 20 is increasing or decreasing, and if the torque of the generator 20 is increasing or decreasing, sets the rate limit RL1 during the period of torque increase or decrease.

[0100] In step S603 , the vehicle controller 30 sets the value of the maximum torque that the engine 10 can exert in the low power generation control state as the upper limit value T1 .

[0101] In this way, regarding power generation in the low-power power generation control state, if the torque in the generator 20 is generated at the same response speed as in the normal power generation control, there is a possibility that the engine will stall and the rotation will slow down. Therefore, the upper limit value T1 of the maximum torque and the rate limit RL1 that makes the change of the torque moderate are set. In addition, in order to stabilize the combustion of the engine 10, a lag period D1 corresponding to the water temperature of the engine 10 is set. In this way, it is possible to avoid engine stalling and slow rotation. In addition, by setting the rate limit RL1 and the upper limit value T1 when the torque command is set, the speed feedback of the engine 10 can be stably achieved. As described above, at least one of the rate limit RL1, the lag period D1 and the upper limit value T1 can be set.

[0102] [Modification 2]

[0103] In the second modification, an example is shown in which the rotation speed of the engine 10 is switched according to the state of the vehicle 1, that is, the vehicle speed, in the low power generation control state. Specifically, in the second modification, two values ​​( Fig. 9 , Fig.10 Examples of LU1 and UR1) are shown.

[0104] [Example of Control of Rotation Speed ​​According to Vehicle Speed]

[0105] Fig. 9 and Fig.10 1 is a diagram showing an example of switching the rotation speed of the engine 10 according to the vehicle speed of the vehicle 1 in the low power generation control state. Fig. 9 FIG. 2 shows an example of switching the rotation speed of the engine 10 when the vehicle speed V1 of the vehicle 1 increases. Fig.10 2 shows an example of switching the rotation speed of the engine 10 when the vehicle speed V2 of the vehicle 1 decreases. Fig. 9 and Fig.10 The horizontal axis shown represents the time axis. Fig. 9 and Fig.10 The vertical axis shown on the upper side of represents the value of the rotation speed of the engine 10, Fig. 9 and Fig.10 The vertical axis shown below represents the value of the vehicle speed of the vehicle 1 .

[0106] exist Fig. 9 and Fig.10, an example of setting two rotation speeds UR1 and LR1 according to the state of the vehicle 1, that is, the vehicle speed, is shown. In addition, the rotation speed UR1 is an example of the rotation speed on the high rotation side, and the rotation speed LR1 is an example of the rotation speed on the low rotation side. Here, regarding the engine sound emitted by the engine 10, it is preferable to set it to a sound of a degree that does not give a sense of disharmony to the user of the vehicle 1. Therefore, when the vehicle 1 is parked, when the vehicle 1 is at a low speed, that is, when the vehicle speed is less than the threshold TH3, the rotation speed LR1 is set. On the other hand, when the vehicle 1 is at a high speed, that is, when the vehicle speed is greater than or equal to the threshold TH3, the rotation speed UR1 is set. However, when the rotation speed LR1 is set, less power is obtained than when the rotation speed UR1 is set. Therefore, it is preferable to set the two rotation speeds UR1 and LR1 in consideration of the sense of disharmony that is assumed to be given to the user of the vehicle 1 and the power required by the vehicle. In addition, the threshold TH3 is a reference value when switching between the two rotation speeds UR1 and LR1, and can be appropriately set based on experimental data, etc., in consideration of the sense of disharmony given to the user of the vehicle 1, the power required by the vehicle 1, etc.

[0107] In the second modification, two rotation speeds are switched according to the required power and the vehicle speed. For example, when the rotation speed of the engine 10 in the normal power generation control state ranges from about 1400 rpm to about 6000 rpm, the values ​​of the two rotation speeds UR1 and LR1 can be set to values ​​in the range of about 1400 rpm to 2200 rpm. For example, the value of the rotation speed LR1 can be set to a lower value in the range of 1400 rpm to 2200 rpm, and the value of the rotation speed UR1 can be set to a higher value in the range of 1400 rpm to 2200 rpm.

[0108] Straight lines L21 and L31 represent target rotation speeds of the engine 10, and curved lines C21 and C31 represent actual rotation speeds of the engine 10. Straight lines L22 and L32 represent target rotation speeds of the engine 10 as a comparative example, and curved lines C22 and C32 represent actual rotation speeds of the engine 10 as a comparative example.

[0109] In the case where the target speed of the engine 10 is switched between the two speeds UR1 and LR1 in the low power generation control state, if the engine speed is to be changed suddenly, Fig. 9 C22 Fig.10 As shown in C32 of FIG. 1 , the overshoot amplitude may increase during acceleration and the undershoot amplitude may increase during deceleration. Therefore, in order to prevent a sudden instruction when changing the rotation speed, the change rates RL2 and RL3 are set in the second modification.

[0110] Here, when the driver of the vehicle 1 intends to drive or accelerate, the vehicle speed of the vehicle 1 increases or the required power increases. In this case, even if the speed is increased and the dark noise increases, it will not give the passengers of the vehicle 1 a sense of disharmony. Therefore, the speed can be switched according to the vehicle speed and the requested power of the vehicle 1. In this way, the speed of the engine 10 is increased according to the driving request of the driver of the vehicle 1, thereby increasing the power obtained in the low power generation control state, and meeting the higher driving performance request.

[0111] In addition, the two rotation speeds UR1 and LR1 may be switched based on conditions other than the vehicle speed. Figure 6 ), in the case where it is determined that the short-term chargeable power PIN_S is greater than or equal to the threshold value TH2, the speed UR1 can be set in step S506. On the other hand, in the case where it is determined that the short-term chargeable power PIN_S is less than the threshold value TH2, the speed LR1 can be set in step S507. In addition, when the speed LR1 is set, the slow-moving lamp can be turned on or flashed. In addition, in Modification 2, an example of setting two speeds UR1 and LR1 and switching between them is shown, but this embodiment can also be applied to the case where three or more speeds are set and they are switched based on the vehicle speed, etc.

[0112] [Structure and Effects of the Present Embodiment]

[0113] In the control method of 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 for driving the vehicle 1; and a battery 40 electrically connected to the generator 20 and the drive motor 50, and supplies the power generated by the generator 20 to at least one of the battery 40 and the drive motor 50. In the control method, in steps S401 to S405, S501 to S504, S506, and S507, when the temperature of the battery 40 is less than or equal to a predetermined temperature, a power generation required torque (an example of a drive torque target value) is calculated based on the requested power of the vehicle 1 and the state of the battery 40, and the torque of the generator 20 is controlled based on the power generation required torque, and the speed of the engine 10 is controlled based on a predetermined reference low speed (for example, the speed UR1 and LR1), thereby executing low power generation control in which the power is generated by the generator 20. For example, in low-power power generation control, torque control is performed to increase or decrease the torque of the generator 20 in a manner to achieve the torque required for power generation calculated based on the requested power of the vehicle 1 and the state of the battery 40, and speed control is performed to increase or decrease the speed of the engine 10 in a manner to make the engine 10 reach a specified reference low speed.

[0114] According to this structure, low-power generation control can be performed even when the temperature of the battery 40 is lower than or equal to the specified temperature, so charging can be continuously performed to ensure the power required for the drive motor 50, auxiliary equipment 60, etc., thereby reducing the risk of power shortage.

[0115] In addition, in the control method of the vehicle 1 according to the present embodiment, it is determined whether the warm-up of the battery 40 is completed based on the state of the battery 40, and when the warm-up of the battery 40 is not completed, it is estimated that the temperature of the battery 40 is less than or equal to a predetermined temperature. Furthermore, in steps S501 to S504, S506, and S507, when the warm-up of the battery 40 is not completed and the requested power of the vehicle 1 is less than the threshold value TH1 (an example of the first threshold value), the low power generation control is performed.

[0116] According to this configuration, when the battery 40 is not completely warmed up and the required power of the vehicle 1 is less than the threshold TH1, the low power generation control is executed, so that the battery 40 can be appropriately charged even at low temperatures.

[0117] In addition, regarding the control method of the vehicle 1 according to the present embodiment, in steps S401 to S405, S501 to S503, and S505, when the warm-up of the battery 40 is completed or the requested power of the vehicle 1 is greater than or equal to the threshold value TH1 (an example of the first threshold value), the torque required for power generation (an example of a target value for drive torque) is calculated based on the requested power of the vehicle 1 and the state of the battery 40, the torque of the engine 10 is controlled based on the torque required for power generation, and the speed of the generator 20 is controlled based on the speed based on the torque required for power generation of the generator 20, thereby executing normal power generation control for generating power using the generator 20. For example, in the normal power generation control, the torque control for increasing or decreasing the torque of the engine 10 is executed so as to achieve the torque required for power generation calculated based on the requested power of the vehicle 1 and the state of the battery 40, and the speed control for increasing or decreasing the speed of the generator 20 is executed so as to achieve the speed based on the torque required for power generation.

[0118] According to this configuration, when the performance of the battery 40 is not degraded and the required power of the vehicle 1 is large, normal power generation control can be performed, thereby ensuring the power required for the drive motor 50 and the auxiliary machines 60 .

[0119] In addition, regarding the control method of the vehicle 1 according to the present embodiment, in steps S506 and S507, in the low power generation control, the torque control of the generator 20 and the speed control of the engine 10 are performed 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 generation control, the torque control of the generator 20 and the speed control of the engine 10 are performed 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.

[0120] According to this configuration, low-power generation control is performed so that the power generated by the generator 20 is within the range of the chargeable power PIN of the battery 40, so that appropriate power generation control corresponding to the chargeable power PIN of the battery 40 can be achieved. As a result, the SOC of the battery 40 can be prevented from being depleted, and charging can be continued even when the vehicle 1 is parked with low power consumption. In addition, the temperature of the battery 40 can be increased, and the low chargeable power state due to low temperature can be exited as soon as possible.

[0121] In addition, regarding the control method of the vehicle 1 according to the present embodiment, in steps S506 and S507, in the low power generation control, the torque control of the generator 20 and the speed control of the engine 10 are performed based on the power generated by the generator 20 and the upper limit SOC of the battery 40 specified in accordance with the battery temperature. For example, in the low power generation control, the torque control of the generator 20 and the speed control of the engine 10 are performed so that the power generated by the generator 20 does not exceed the upper limit SOC of the battery 40 specified in accordance with the battery temperature.

[0122] According to this configuration, low power generation control is performed so that the power generated by the generator 20 does not exceed the upper limit SOC of the battery 40, thereby achieving appropriate power generation control corresponding to the upper limit SOC of the battery 40. In addition, a decrease in the chargeable power PIN caused by an increase in the SOC of the battery 40 can be prevented.

[0123] In addition, regarding the control method of the vehicle 1 according to the present embodiment, in steps S506, S507, and S601 to S603, in the low power generation control, 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 change rate when the drive torque of the generator 20 is changed is performed. For example, Figure 7 As shown, at least one of the delay process of setting the lag period D1, the torque limit process of setting the upper limit value T1, and the limit process of setting the rate limit RL1 can be executed.

[0124] According to this configuration, by executing the above-described processes, it is possible to avoid a significant change in the rotation of the engine 10 and engine stall in the low-power generation control state.

[0125] In addition, regarding the control method of the vehicle 1 involved in this embodiment, as shown in FIG. Fig. 9 , Fig.10 As shown, as the reference low speed, either the first low speed LR1 or the second low speed UR1 having a value greater than the first low speed LR1 is set. In steps S506 and S507, in the low power generation control, the first low speed LR1 and the second low speed UR1 are switched as the speed of the engine 10 based on at least one of the requested power of the vehicle 1 and the vehicle speed of the vehicle 1.

[0126] According to this configuration, the rotation speed of the engine 10 is switched according to the travel request of the driver of the vehicle 1, thereby adjusting the electric power obtained in the low-power generation control state, and satisfying a request for higher travel performance.

[0127] In addition, regarding the control method of the vehicle 1 according to the present embodiment, in steps S506 and S507, when the rotation speed of the engine 10 is switched, a change rate limiting process is performed to limit the change rate of the rotation speed of the engine 10 between the first low rotation speed LR1 and the second low rotation speed UR1. Fig. 9 , Fig.10 As shown, it is possible to execute the change rate limiting process of setting the change rates RL2 and RL3.

[0128] According to this configuration, when the rotation speed of the engine 10 is switched, the rotation speed change rate is limited, so that a sudden rotation speed instruction can be prevented, and overshoot and undershoot of the engine 10 can be avoided in the low power generation control state.

[0129] In addition, regarding the control method of the vehicle 1 according to the present embodiment, in steps S504 and S507, in the low power generation control, when the short-term chargeable power PIN_S (an example of chargeable power) of the battery 40 corresponding 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 of the degradation of the driving performance of the vehicle 1. As the vehicle driving performance degradation notification process, for example, the slow-moving lamp may be lit or flashed.

[0130] According to this configuration, it is possible to notify the driver that the running performance of the vehicle 1 has deteriorated by transitioning to the low power generation control state.

[0131] In addition, a control device 100 of a vehicle 1 is provided. 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 that is electrically connected to the generator 20 and the drive motor 50. The control device 100 supplies power generated by the generator 20 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 calculates a power generation required torque (an example of a drive torque target value) based on the requested power of the vehicle 1 and the state of the battery 40 when the temperature of the battery 40 is less than or equal to a predetermined temperature, performs torque control on the generator 20 based on the power generation required torque, and performs speed control on the engine 10 based on a predetermined reference low speed (for example, the speed UR1 and LR1), thereby being able to perform low power generation control in which power is generated by the generator 20.

[0132] According to this structure, low-power generation control can be performed even when the temperature of the battery 40 is lower than or equal to the specified temperature, so charging for ensuring the power required for the drive motor 50, auxiliary equipment 60, etc. can be continuously performed, and the risk of power shortage can be reduced.

[0133] In addition, each processing flow shown in this embodiment shows an example for implementing this embodiment, and the order of a part of each processing flow may be changed within the scope of being able to implement this embodiment, a part of each processing flow may be omitted, or other processing flows may be added.

[0134] In addition, each process shown in this embodiment is executed based on a program for causing a computer to execute each process flow. Therefore, this embodiment can also be understood as an embodiment of a program that realizes the function of executing each of the above processes and a recording medium storing the program. For example, the program can be stored in a storage device of a control device through an update process for adding a new function to the control device. Thus, the updated control device can implement each process shown in this embodiment.

[0135] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific structures of the above embodiments.

Claims

1. A method for controlling a vehicle, the 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, supplying power generated by the generator to at least one of the battery and the drive motor, wherein: calculating a drive torque target value based on the requested power of the vehicle and the state of the battery, determining whether the battery is fully warmed up based on the battery status, When the battery is not warmed up and the requested power of the vehicle is less than a first threshold, the generator is torque controlled based on the drive torque target value, and the engine speed is controlled based on a specified reference low speed, thereby executing low-power power generation control using the generator to generate power.

2. The vehicle control method according to claim 1, wherein: When the battery is warmed up, or the requested power of the vehicle is greater than or equal to the first threshold, a drive torque target value is calculated based on the requested power of the vehicle and the state of the battery, the engine is torque controlled based on the drive torque target value, and the generator is speed controlled according to the speed based on the drive torque target value, thereby performing normal power generation control using the generator to generate electricity.

3. The vehicle control method according to claim 1, wherein: In the low-power generation control, torque control of the generator and rotation speed control of the engine are performed based on the generated power of the generator and the chargeable power of the battery corresponding to the temperature of the battery.

4. The vehicle control method according to claim 1, wherein: In the low-power generation control, torque control of the generator and rotation speed control of the engine are executed based on the power generated by the generator and an upper limit SOC of the battery specified according to the battery temperature.

5. The vehicle control method according to claim 1, wherein: In the low power generation control, at least one of a delay process for delaying a torque control start timing of the generator, a torque limit process for limiting a maximum drive torque of the generator, and a limit process for limiting a rate of change when changing the drive torque of the generator is performed.

6. The vehicle control method according to claim 1, wherein: As the reference low speed, either a first low speed or a second low speed greater than the first low speed is set. In the low power generation control, the first low speed and the second low speed are switched as the speed of the engine based on at least one of the requested power of the vehicle and the vehicle speed of the vehicle.

7. The vehicle control method according to claim 6, wherein: When the rotation speed of the engine is switched, a change rate limiting process is performed to limit the change rate of the rotation speed of the engine between the first low rotation speed and the second low rotation speed.

8. The vehicle control method according to claim 1, wherein: In the low power generation control, when chargeable power of the battery corresponding to the temperature of the battery is less than a second threshold value, a vehicle running performance degradation notification process is executed to notify a passenger of a degradation in running performance of the vehicle.

9. The vehicle control method according to any one of claims 1 to 8, wherein: The requested power of the vehicle is the total value of the power required by the drive motor and the power required by the auxiliary machinery of the vehicle. In the low-power power generation control, the drive torque target value is calculated within the range of the rechargeable power of the battery set based on the short-term rechargeable power that can charge the battery in the short term and the long-term rechargeable power that can charge the battery in the long term.

10. A control device for a vehicle, the vehicle comprising: a generator; an engine connected to the generator; a drive motor that drives the vehicle; and a battery that is electrically connected to the generator and the drive motor and supplies power generated by the generator to at least one of the battery and the drive motor, wherein: calculating a drive torque target value based on the requested power of the vehicle and the state of the battery, determining whether the battery is fully warmed up based on the battery status, When the battery is not warmed up and the requested power of the vehicle is less than a first threshold, the generator is torque controlled based on the drive torque target value, and the engine speed is controlled based on a specified reference low speed, thereby executing low-power power generation control using the generator to generate power.

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