JP7204509B2 - vehicle - Google Patents

Description

The present invention relates to power systems.

2. Description of the Related Art In recent years, hybrid vehicles that run using a drive motor and an engine as drive sources have been widely used. For example, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-100000, the power supply system of a hybrid vehicle includes, as power supply sources, a main battery (that is, a high-voltage battery) that stores electric power supplied to a driving motor, and a main battery. A sub-battery (that is, a low-voltage battery) is connected to the main battery via a DCDC converter capable of stepping down the power stored in the sub-battery. In such a power supply system, the sub-battery is charged with power supplied from the main battery via the DCDC converter, and power is supplied from the sub-battery to various auxiliary devices in the vehicle.

JP 2016-155439 A

By the way, in the power supply system of a hybrid vehicle, an abnormality of the sub-battery such as a short circuit in a cell of the sub-battery may occur. Specifically, in a vehicle in which the sub-battery is charged using the power output from the engine in the HEV driving mode in which the power of the engine and the drive motor is used to drive, when the sub-battery malfunctions, , there is a risk of damage to the sub-battery in which an abnormality has occurred due to overcharging. Here, in order to protect the sub-battery when there is an abnormality in the sub-battery, it is conceivable to prevent overcharging of the sub-battery by stopping the power supply system. However, when the power supply system is stopped, the vehicle becomes unable to run, resulting in problems such as a decrease in convenience.

Furthermore, when the sub-battery is abnormal, there is a possibility that the startability may not be sufficiently ensured. Specifically, when the power output from the engine is used to start the vehicle, and the electric power stored in the sub-battery is used to drive the starting motor that starts the engine, the sub-battery When there is an abnormality in the battery, it may become difficult to drive the starting motor using the electric power stored in the sub-battery, which may hinder the start of the vehicle.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to protect the sub-battery and to improve the running of the vehicle while appropriately ensuring the startability when the sub-battery malfunctions. To provide a new and improved power supply system capable of realizing continuation.

In order to solve the above problems, according to one aspect of the present invention, there is provided a driving motor, an engine, a starting motor for starting the engine, and a main battery for storing electric power supplied to the driving motor. a sub-battery connected to the main battery via a DCDC converter capable of storing power supplied to the starting motor and stepping down the power stored in the main battery; a control device having a control unit capable of switching between an HEV travel mode in which the vehicle travels using power and an EV travel mode in which the vehicle travels using the power of the drive motor while the engine is stopped. In the vehicle, the vehicle is started using the power output from the engine, and the control unit diagnoses that the sub-battery is normal when an engine start request is made when the vehicle is started. In this case, the engine is started by driving the starting motor using the electric power stored in the sub-battery without using the electric power stored in the main battery, and when the engine start request is made, the sub-battery When the battery is diagnosed to be abnormal, the electric power supplied from the main battery via the DCDC converter is used to drive the starting motor to start the engine, and then the sub-battery is charged. A vehicle is provided that performs fail-safe control to reduce the amount or amount of discharge compared to when the sub-battery is diagnosed as normal.

When the sub-battery is diagnosed to be abnormal at the time of the engine start request, the control unit prohibits the start of the engine if the degree of abnormality of the sub-battery exceeds a standard. good.

In the fail-safe control, the control unit prohibits the HEV running mode and permits the EV running mode when the remaining capacity of the main battery is equal to or greater than a threshold, and the remaining capacity of the main battery is greater than the threshold. If it is low, the HEV driving mode may be permitted.

When the threshold is a first threshold, the control unit permits the HEV driving mode in the fail-safe control when the remaining capacity of the main battery is higher than a second threshold that is larger than the first threshold. You may

As described above, according to the present invention, it is possible to protect the sub-battery and continue the running of the vehicle while appropriately ensuring startability when the sub-battery is abnormal.

1 is a schematic diagram showing a schematic configuration of a power supply system according to an embodiment of the present invention; FIG. It is a block diagram showing an example of functional composition of a control device concerning the embodiment. FIG. 4 is a schematic diagram showing a power transmission state during an HEV running mode in the power supply system according to the same embodiment; FIG. 4 is a schematic diagram showing a power transmission state during an EV running mode in the power supply system according to the same embodiment; 4 is a flowchart showing a first example of the overall flow of processing performed by the control device according to the embodiment; 4 is a flow chart showing an example of the flow of processing in fail-safe control performed by the control device according to the embodiment; FIG. 7 is a flowchart showing an example different from FIG. 6 of the flow of processing in fail-safe control performed by the control device according to the same embodiment. FIG. 7 is a flow chart showing a second example of the overall flow of processing performed by the control device according to the embodiment;

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<1. Configuration of power supply system>
First, the configuration of a power supply system 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG.

FIG. 1 is a schematic diagram showing a schematic configuration of a power supply system 1. As shown in FIG. FIG. 2 is a block diagram showing an example of the functional configuration of the control device 100. As shown in FIG.

Specifically, the power supply system 1 is a system mounted on a hybrid vehicle and used to supply electric power to each device in the vehicle. In a hybrid vehicle equipped with the power supply system 1, as will be described later, there is an HEV running mode in which the power of the engine 12 and the drive motor 11 is used to run, and a state in which the power of the drive motor 11 is used while the engine 12 is stopped. In the HEV running mode, the power output from the engine 12 is used to charge the sub-battery 22 . Further, in a hybrid vehicle in which the power supply system 1 is mounted, the vehicle is started using the power output from the engine 12, as will be described later.

The power supply system 1 described below is merely an example of the power supply system according to the present invention, and the configuration of the power supply system according to the present invention is not particularly limited to the configuration of the power supply system 1 as described later.

As shown in FIG. 1, the power supply system 1 includes a driving motor 11, an engine 12, a starting motor 13, a main battery 21, a sub-battery 22, a DCDC converter 42, and a control device 100. . Further, the power supply system 1 includes a transmission 31, an inverter 41, an auxiliary device 51, a system main relay 61, a diagnostic relay 62, a main battery sensor 91, a sub-battery sensor 92, and a vehicle speed sensor 93. Prepare.

The drive motor 11 is a motor capable of outputting power for driving the drive wheels 5 of the vehicle. As the drive motor 11, for example, a polyphase AC motor (for example, a three-phase AC motor) is used. The drive motor 11 is connected to the main battery 21 via the inverter 41 and generates power using electric power supplied from the main battery 21 via the inverter 41 . At this time, the DC power discharged from the main battery 21 is converted into AC power by the inverter 41 and supplied to the drive motor 11 .

Further, the drive motor 11 may have a function (regenerative function) as a generator that generates power using the rotational energy of the drive wheels 5 when the vehicle is decelerated. At this time, the AC power generated by the driving motor 11 is converted into DC power by the inverter 41 and supplied to the main battery 21 . As a result, the main battery 21 is charged with the electric power generated by the drive motor 11 .

The engine 12 is an internal combustion engine that uses gasoline or the like as fuel to generate power, and is capable of outputting power for driving the drive wheels 5 of the vehicle. A crankshaft, which is an output shaft of the engine 12, is connected to a transmission 31 via a torque converter, a clutch, or the like (not shown). As the transmission 31, for example, one having a continuously variable transmission mechanism such as a CVT (Continuously Variable Transmission) is used. Power output from the engine 12 is changed by the transmission 31 and transmitted to the driving wheels 5 . The drive motor 11 described above may be connected to the drive wheels 5 via the transmission 31 or may be connected to the drive wheels 5 without the transmission 31 .

The starting motor 13 is a motor for starting the engine 12 . The output shaft of the starting motor 13 is connected to the crankshaft of the engine 12 via gears, so that power output from the starting motor 13 is transmitted to the crankshaft of the engine 12 . The starting motor 13 is connected to the sub-battery 22 and basically uses the electric power supplied from the sub-battery 22 to generate power. As will be described later, the power supplied from the main battery 21 via the DCDC converter 42 can also be used to drive the starting motor 13 .

For example, a DC motor or an AC motor may be used as the starting motor 13 . When an AC motor is used as the starting motor 13, the starting motor 13 is connected to the sub-battery 22 via an inverter (not shown), and the DC power discharged from the sub-battery 22 is converted to AC power by the inverter. It is converted and supplied to the starting motor 13 .

Also, the starting motor 13 can generate power using the power output from the engine 12 . Electric power generated by the starting motor 13 is supplied to the sub-battery 22 . As a result, the sub-battery 22 is charged with the electric power generated by the starting motor 13 . Specifically, the charging of the sub-battery 22 using the power output from the engine 12 is performed in the HEV running mode, as will be described later.

The main battery 21 is a battery that stores electric power supplied to the drive motor 11 . The main battery 21 is specifically a battery with a higher voltage (for example, 100 V) than the sub-battery 22. As the main battery 21, for example, a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery is used. .

Specifically, as will be described later, the main battery 21 is connected to each device in the vehicle (specifically, the auxiliary device 51, the sub-battery, etc.) via a DCDC converter 42 capable of stepping down the power stored in the main battery 21. 22 and the starting motor 13), and the power stored in the main battery 21 can be stepped down by the DCDC converter 42 and supplied to each device. A system main relay 61 is provided between the main battery 21 and the DCDC converter 42 . The system main relay 61 is capable of connecting and disconnecting the electrical connection between the main battery 21 and the DCDC converter 42 on both the positive side and the negative side, and is in an open state when the power supply system 1 is stopped. , is closed after the power supply system 1 is started.

The sub-battery 22 is a battery that stores electric power supplied to the starting motor 13 and is connected to the main battery 21 via the DCDC converter 42 . Specifically, the sub-battery 22 is a battery with a lower voltage (for example, 12 V) than the main battery 21. As the sub-battery 22, for example, a secondary battery such as a lead-acid battery or a lithium-ion battery is used.

Specifically, the sub-battery 22 is connected to the auxiliary device 51 so that the power stored in the sub-battery 22 is basically supplied to the auxiliary device 51 . Auxiliary machine 51 includes, for example, various types of equipment such as air conditioning equipment or audio equipment in the vehicle. Here, the sub-battery 22 is connected to the auxiliary machine 51 via the diagnostic relay 62 . The diagnostic relay 62 is a switch capable of connecting and disconnecting electrical connections between the sub-battery 22 and the starting motor 13, the auxiliary device 51 and the main battery 21, and performs abnormality diagnosis of the sub-battery 22, which will be described later. is established for The diagnostic relay 62 is in an open state when the abnormality diagnosis of the sub-battery 22 is executed, and basically in a closed state when the abnormality diagnosis is not executed.

The main battery sensor 91 detects various state quantities of the main battery 21 and outputs them to the control device 100 . Specifically, the main battery sensor 91 detects the remaining capacity of the main battery 21 (hereinafter also referred to as SOC (State Of Charge)).

The sub-battery sensor 92 detects various state quantities of the sub-battery 22 and outputs them to the control device 100 . Specifically, the sub-battery sensor 92 detects the voltage and internal resistance of the sub-battery 22 .

Vehicle speed sensor 93 detects vehicle speed, which is the speed of the vehicle, and outputs it to control device 100 .

The control device 100 includes a CPU (Central Processing Unit) that is an arithmetic processing unit, a ROM (Read Only Memory) that is a storage element that stores programs used by the CPU and calculation parameters, and parameters that change as appropriate during execution of the CPU. It is composed of a RAM (Random Access Memory) or the like, which is a storage element for temporary storage.

Also, the control device 100 communicates with each device mounted on the power supply system 1 . Communication between the control device 100 and each device is realized using CAN (Controller Area Network) communication, for example.

Note that the functions of the control device 100 according to the present embodiment may be at least partially divided by a plurality of control devices, and the plurality of functions may be realized by a single control device. For example, the function of controlling the operation of the driving motor 11, the function of controlling the operation of the engine 12, and other functions, which are functions of the control device 100, may be divided into separate control devices. When the functions of the control device 100 are at least partially divided by a plurality of control devices, the plurality of control devices may be connected to each other via a communication bus such as CAN.

For example, as shown in FIG. 2, the control device 100 has an acquisition section 110 and a control section 120 .

Acquisition unit 110 acquires various types of information used in processing performed by control unit 120 . Acquisition unit 110 also outputs the acquired information to control unit 120 . For example, the acquisition unit 110 acquires various information output from each sensor by communicating with each sensor of the main battery sensor 91, the sub battery sensor 92, and the vehicle speed sensor 93. FIG.

The control unit 120 controls the operation of each device of the power supply system 1 . For example, control unit 120 includes motor control unit 121 , engine control unit 122 , relay control unit 123 , converter control unit 124 , and diagnosis unit 125 .

The motor control section 121 controls the operation of the drive motor 11 . Specifically, the motor control unit 121 controls the power supply between the drive motor 11 and the main battery 21 by controlling the operation of the switching elements of the inverter 41 . Thereby, the motor control unit 121 can control the power generation and power generation by the driving motor 11 .

The engine control section 122 controls the operation of the engine 12 . Specifically, the engine control unit 122 controls the throttle opening, ignition timing, fuel injection amount, and the like by controlling the operation of each device in the engine 12 . Thereby, the engine control section 122 can control the output of the engine 12 .

Also, the engine control unit 122 controls the operation of the starting motor 13 . Specifically, the engine control unit 122 controls the power supply between the starting motor 13 and the sub-battery 22 to start the engine 12 by the starting motor 13 and control the power output from the engine 12. The power generation used can be controlled. Note that the engine control unit 122 can cooperate with a relay control unit 123 described later to drive the starting motor 13 using power supplied from the main battery 21 via the DCDC converter 42 .

The relay control unit 123 controls operations of the system main relay 61 and the diagnostic relay 62 . Specifically, the relay control unit 123 controls the operation of a driving device (not shown) that drives each of the system main relay 61 and the diagnostic relay 62, thereby opening and closing the system main relay 61 and the diagnostic relay 62. control respectively.

More specifically, the relay control unit 123 keeps the system main relay 61 open when the ignition switch is READY-OFF and the power supply system 1 is stopped. On the other hand, the relay control unit 123 basically controls the system when an engine start request (that is, a request to start the engine 12) is generated by an operation using the ignition switch by the driver when the vehicle starts moving. By closing the main relay 61, the power supply system 1 is activated.

In addition, the relay control unit 123 keeps the diagnostic relay 62 in an open state when executing the abnormality diagnosis of the sub-battery 22 . On the other hand, the relay control unit 123 basically keeps the diagnostic relay 62 closed when the abnormality diagnosis of the sub-battery 22 is not executed.

Converter control unit 124 controls the operation of DCDC converter 42 . Specifically, the converter control unit 124 controls power supply between the main battery 21 and the auxiliary device 51, the sub-battery 22, and the starting motor 13 by controlling the operation of the switching elements of the DCDC converter 42. do.

Diagnosis unit 125 diagnoses the presence or absence of abnormality in sub-battery 22 . For example, the diagnosis unit 125 diagnoses whether or not the sub-battery 22 has a short circuit, which is a state in which a short circuit occurs in a cell included in the sub-battery 22 , as the presence or absence of an abnormality in the sub-battery 22 . Further, for example, the diagnostic unit 125 determines whether the sub-battery 22 is in a state where the electrodes in the cells included in the sub-battery 22 are chemically or physically degraded, as the presence/absence of an abnormality in the sub-battery 22. Diagnose.

By controlling the operations of the drive motor 11 and the engine 12 as described above, the control unit 120 can switch between the HEV running mode and the EV running mode as the running mode of the vehicle.

For example, the control unit 120 basically switches the driving mode of the vehicle based on the required driving force, which is the required value of the power transmitted to the driving wheels 5 . Specifically, control unit 120 switches the running mode of the vehicle to the HEV running mode when the required driving force is greater than the reference driving force. On the other hand, control unit 120 switches the running mode of the vehicle to the EV running mode when the required driving force is equal to or less than the reference driving force. The reference driving force is set to a value smaller than the maximum value of the power that can be transmitted from the driving motor 11 to the driving wheels 5, and is set according to the specifications of the driving motor 11, for example, from the viewpoint of improving electric power consumption. . Note that the control unit 120 can calculate the required driving force based on the accelerator opening and the vehicle speed, for example.

FIG. 3 is a schematic diagram showing a power transmission state in the power supply system 1 during the HEV running mode.

In the HEV driving mode, the motor control unit 121 and the engine control unit 122 of the control unit 120 cooperate with each other so that the power transmitted to the driving wheels 5 becomes the required driving force, and the outputs of the driving motor 11 and the engine 12 are controlled. control respectively. As a result, as shown in FIG. 3, power F10 output from the drive motor 11 is transmitted to the driving wheels 5, and power F21 output from the engine 12 is transmitted to the driving wheels 5 via the transmission 31. transmitted. Thus, in the HEV running mode, the vehicle runs using the power of the engine 12 and the driving motor 11 .

Here, in the HEV driving mode, the power F22 output from the engine 12 can be transmitted to the starting motor 13. As shown in FIG. As a result, electric power is generated by the starting motor 13, and the electric power E10 generated by the starting motor 13 is supplied to the sub-battery 22, whereby the sub-battery 22 can be charged. Thus, in the HEV running mode, the power output from the engine 12 is used to charge the sub-battery 22 .

In the HEV running mode, when a predetermined condition is satisfied, such as when the SOC of the main battery 21 is equal to or higher than a reference value, power is supplied from the main battery 21 to the sub-battery 22 via the DCDC converter 42. The charging of the sub-battery 22 may be performed by turning on.

FIG. 4 is a schematic diagram showing a power transmission state in the power supply system 1 during the EV running mode.

In the EV driving mode, the engine control unit 122 of the control unit 120 stops the engine 12, and the motor control unit 121 controls the output of the driving motor 11 so that the power transmitted to the driving wheels 5 becomes the required driving force. Control. As a result, only the power F10 output from the drive motor 11 is transmitted to the drive wheels 5, as shown in FIG. Thus, in the EV running mode, the vehicle runs using the power of the drive motor 11 with the engine 12 stopped.

Here, in the EV drive mode, for example, a clutch (not shown) that connects and disconnects the transmission of power between the engine 12 and the drive motor 11 is released so that power is not transmitted to the starter motor 13 . Therefore, since power generation by the starting motor 13 is stopped, at least the charging of the sub-battery 22 using the power output from the engine 12 is not performed.

In the control device 100 according to the present embodiment, when the sub-battery 22 is diagnosed as normal at the time of an engine start request at the start of the vehicle, the control unit 120 does not use the electric power stored in the main battery 21. The electric power stored in the sub-battery 22 is used to drive the starting motor 13 to start the engine 12 . On the other hand, when the sub-battery 22 is diagnosed to be abnormal when the engine start request is made when the vehicle starts moving, the control unit 120 uses the electric power supplied from the main battery 21 via the DCDC converter 42 to start the starting motor. 13 to start the engine 12, and then perform fail-safe control to reduce the charge amount or discharge amount of the sub-battery 22 compared to when the sub-battery 22 is diagnosed as normal. As a result, when the sub-battery 22 is abnormal, it is possible to protect the sub-battery 22 and continue the running of the vehicle while appropriately ensuring startability. The details of the control performed by the control unit 120 at the time of the engine start request will be described later.

<2. Operation of Power Supply System>
Next, operation of the power supply system 1 according to the embodiment of the present invention will be described with reference to FIGS. 5 to 8. FIG. In addition, below, the 1st example and the 2nd example are demonstrated in this order as an example of the whole flow of the process which the control apparatus 100 of the power supply system 1 performs.

[2-1. First example]
First, a first example of the overall flow of processing performed by the control device 100 will be described with reference to FIGS. 5 to 7. FIG.

FIG. 5 is a flow chart showing a first example of the overall flow of processing performed by the control device 100 . Specifically, the control flow according to the first example shown in FIG. be done. Therefore, when the control flow according to the first example shown in FIG. 5 is started, the system main relay 61 is in an open state.

When the control flow according to the first example shown in FIG. 5 is started, first, in step S501, the control unit 120 determines whether or not an engine start request has occurred. If it is determined that an engine start request has occurred (step S501/YES), the process proceeds to step S503. On the other hand, if it is determined that the engine start request has not occurred (step S501/NO), the process of step S501 is repeated.

For example, the control unit 120 can determine whether or not an engine start request has occurred based on information indicating an operation using the ignition switch, which is output from the ignition switch to the control device 100 .

If YES is determined in step S501, control unit 120 diagnoses whether sub-battery 22 is abnormal in step S503. If the sub-battery 22 is diagnosed as abnormal (step S503/YES), the process proceeds to step S505. On the other hand, if the sub-battery 22 is diagnosed as normal (step S503/NO), the process proceeds to step S511.

As described above, the diagnostic unit 125 diagnoses whether the sub-battery 22 is abnormal. Further, the diagnosis unit 125 diagnoses whether the sub-battery 22 is abnormal, for example, whether the sub-battery 22 is short-circuited or whether the sub-battery 22 is deteriorated.

For example, the diagnosis unit 125 diagnoses whether or not the sub-battery 22 is short-circuited based on the open-circuit voltage of the sub-battery 22 . Specifically, the diagnosis unit 125 diagnoses that the sub-battery 22 is short-circuited when it is determined that the open-circuit voltage of the sub-battery 22 is lower than the voltage threshold. On the other hand, the diagnosis unit 125 diagnoses that the sub-battery 22 is not short-circuited when it is determined that the open-circuit voltage of the sub-battery 22 is equal to or higher than the voltage threshold.

When the sub-battery 22 is short-circuited, the open-circuit voltage of the sub-battery 22 is lower than normal. Therefore, by comparing the open-circuit voltage of the sub-battery 22 with the voltage threshold as described above, it is possible to appropriately diagnose whether the sub-battery 22 is short-circuited. The voltage threshold is set, for example, to a value that is higher than the open-circuit voltage of the sub-battery 22 assumed when one cell of the sub-battery 22 is short-circuited and lower than the open-circuit voltage of the sub-battery 22 in the normal state.

Further, for example, the diagnosis unit 125 diagnoses whether or not the sub-battery 22 has deteriorated based on the internal resistance of the sub-battery 22 . Specifically, the diagnosis unit 125 diagnoses that the sub-battery 22 is deteriorated when it is determined that the internal resistance of the sub-battery 22 is greater than the resistance threshold. On the other hand, the diagnosis unit 125 diagnoses that the sub-battery 22 has not deteriorated when it is determined that the internal resistance of the sub-battery 22 is equal to or less than the resistance threshold.

When the sub-battery 22 is degraded, the internal resistance of the sub-battery 22 becomes higher than that in the normal state. Therefore, by comparing the internal resistance of the sub-battery 22 with the resistance threshold as described above, it is possible to appropriately diagnose whether the sub-battery 22 is degraded. The resistance threshold is set, for example, to a value that is lower than the internal resistance of the sub-battery 22 assumed when one cell of the sub-battery 22 is degraded and higher than the internal resistance of the sub-battery 22 under normal conditions.

Here, from the viewpoint of appropriately diagnosing whether or not there is an abnormality in the sub-battery 22, it is preferable that the diagnosis of whether or not there is an abnormality in the sub-battery 22 is performed while the diagnostic relay 62 is open. When the diagnostic relay 62 is open, the sub-battery 22 and the starting motor 13 are electrically cut off from the auxiliary device 51 and the main battery 21 . Therefore, the supply of electric power from the sub-battery 22 to the auxiliary device 51 and the supply of electric power from the main battery 21 to the sub-battery 22 are stopped. Therefore, the sub-battery sensor 92 can detect an appropriate value as an electrical state quantity (specifically, voltage and internal resistance) of the sub-battery 22 compared to when current is flowing through the sub-battery 22. can. As a result, the electrical state quantity of the sub-battery 22 used for diagnosing whether the sub-battery 22 is abnormal can be set to a more appropriate value. Therefore, the presence or absence of abnormality in the sub-battery 22 can be properly diagnosed.

Under circumstances where it is difficult to open the diagnostic relay 62, or when the diagnostic relay 62 is omitted from the configuration of the power supply system 1, the presence or absence of an abnormality in the sub-battery 22 can be diagnosed. It is preferable that this is performed while the current input to and output from the battery 22 is within a predetermined range. Specifically, the predetermined range is set to a range in which it is possible to appropriately determine whether or not the influence of the current input/output to/from the sub-battery 22 on the detected value of the electrical state quantity of the sub-battery 22 is relatively small. be done.

If YES in step S503, control unit 120 closes system main relay 61 in step S505. As a result, the main battery 21 and each device including the starting motor 13 are electrically connected.

Next, in step S<b>507 , control unit 120 starts engine 12 using the power of main battery 21 .

Specifically, the control unit 120 controls the operation of the DCDC converter 42 to supply the electric power stored in the main battery 21 to the starting motor 13 via the DCDC converter 42 . Then, the starting motor 13 is driven, the power output from the starting motor 13 is transmitted to the engine 12, and the engine 12 is started. As a result, the vehicle is started, and the vehicle is driven using at least the power output from the engine 12 .

Next, in step S509, control unit 120 executes fail-safe control. Fail-safe control, as described above, is control that reduces the charge amount or discharge amount of the sub-battery 22 compared to when the sub-battery 22 is diagnosed as normal.

Here, with reference to FIGS. 6 and 7, processing in fail-safe control will be described in more detail.

FIG. 6 is a flow chart showing an example of the flow of processing in fail-safe control performed by the control device 100. As shown in FIG.

When the control flow shown in FIG. 6 is started, first, in step S591, control unit 120 determines whether the SOC of main battery 21 is greater than or equal to the first threshold. If it is determined that the SOC of the main battery 21 is equal to or higher than the first threshold (step S591/YES), the process proceeds to step S592. On the other hand, if it is determined that the SOC of the main battery 21 is lower than the first threshold (step S591/NO), the process of step S591 is repeated.

Here, in the EV travel mode, unlike the HEV travel mode, the engine 12 is stopped, so the cruising range is shorter than in the HEV travel mode. Furthermore, the cruising distance in the EV traveling mode becomes shorter as the SOC of the main battery 21 becomes lower. The first threshold is set to a value that can appropriately determine whether the SOC of the main battery 21 is so low that the cruising distance in the EV traveling mode becomes excessively short. That is, when it is determined that the SOC of the main battery 21 is lower than the first threshold value, this corresponds to a case where the cruising distance in the EV traveling mode becomes excessively short.

If YES in step S591, control unit 120 prohibits the HEV running mode and permits the EV running mode in step S509.

Specifically, control unit 120 switches the running mode to the EV running mode, and prohibits the subsequent switching of the running mode to the HEV running mode.

As described above, in the example shown in FIG. 6, the control unit 120 prohibits the HEV driving mode in the fail-safe control when the SOC of the main battery 21 is equal to or higher than the threshold (specifically, the first threshold). to permit the EV running mode.

Here, when the vehicle travels using the power output from the engine 12 as in the HEV travel mode, the sub-battery 22 is charged with electric power generated by the starting motor 13 driven by the engine 12 . On the other hand, in the EV driving mode, the engine 12 is stopped. Therefore, by prohibiting the HEV driving mode and permitting the EV driving mode, the charging of the sub-battery 22 using the power output from the engine 12 can be stopped by switching the driving mode to the EV driving mode. . Therefore, by prohibiting the HEV running mode and permitting the EV running mode when the sub-battery 22 is diagnosed to be abnormal, the vehicle can be prevented from being unable to run, and the abnormality can be prevented. It is possible to appropriately suppress overcharging of the sub-battery 22 that is present. Therefore, when the sub-battery 22 is abnormal, the protection of the sub-battery 22 and the continuation of the running of the vehicle can be properly achieved.

Furthermore, as described above, in the example shown in FIG. 6, control unit 120 switches to the HEV running mode in fail-safe control when the SOC of main battery 21 is lower than the threshold (specifically, the first threshold). to approve. As a result, it is possible to avoid switching the driving mode to the EV driving mode when the cruising distance in the EV driving mode becomes excessively short. Therefore, when the sub-battery 22 becomes abnormal, it is possible to more appropriately prevent the vehicle from being unable to run, so it is possible to more appropriately realize continuation of the running of the vehicle.

FIG. 7 is a flowchart showing an example of the flow of processing in fail-safe control performed by the control device 100, which is different from that shown in FIG.

The control flow shown in FIG. 7 differs from the control flow shown in FIG. 6 in that determination processing in step S591 is added after determination processing in step S591.

Specifically, in the control flow shown in FIG. 7, if YES is determined in step S591, unlike the control flow shown in FIG. 7, the process proceeds to step S593.

If YES in step S591, control unit 120 determines in step S593 whether the SOC of main battery 21 is higher than a second threshold that is higher than the first threshold. If it is determined that the SOC of the main battery 21 is equal to or lower than the second threshold (step S593/NO), the process proceeds to step S592. On the other hand, if it is determined that the SOC of the main battery 21 is higher than the second threshold (step S593/YES), the process of step S593 is repeated.

Here, during regenerative braking in which braking force is generated by causing the drive motor 11 to generate power, the power generated by the drive motor 11 is supplied to the main battery 21 . However, if the SOC of the main battery 21 is excessively high, the electric power that can be charged to the main battery 21 is greatly restricted, making it difficult to perform regenerative braking appropriately. The second threshold is a value larger than the first threshold, and is set to a value that can appropriately determine whether the SOC of the main battery 21 is so high that the power that can be charged to the main battery 21 is greatly limited. be done. That is, when it is determined that the SOC of the main battery 21 is higher than the second threshold value, it becomes difficult to appropriately perform regenerative braking because the power that can be charged to the main battery 21 is greatly limited. corresponds to the case

As described above, in the example shown in FIG. 7, control unit 120 permits the HEV running mode in fail-safe control when the SOC of main battery 21 is higher than the second threshold, which is larger than the first threshold. . As a result, when it becomes difficult to appropriately perform regenerative braking due to the large limitation of the electric power that can be charged to the main battery 21, the running mode is prevented from being switched to the EV running mode. can be done. Here, in the EV driving mode, the transmission of power between the engine 12 and the drive wheels 5 is cut off, so engine braking cannot be used. Therefore, in the EV driving mode, when it becomes difficult to appropriately perform regenerative braking, it may be difficult to appropriately control the behavior of the vehicle. Therefore, by avoiding switching the driving mode to the EV driving mode when it becomes difficult to appropriately perform regenerative braking, it is possible to suppress difficulty in appropriately controlling the behavior of the vehicle. Therefore, when the sub-battery 22 becomes abnormal, the vehicle can continue to run more appropriately.

In addition, although an example in which steps S591 and S593 are executed in this order has been described above, the order of steps S591 and S593 may be reversed.

Returning to FIG. 5, the description will be continued.

If NO in step S503, control unit 120 starts engine 12 using the power of sub-battery 22 in step S511.

Specifically, the control unit 120 causes the electric power stored in the sub-battery 22 to be supplied to the starting motor 13 . Then, the starting motor 13 is driven, the power output from the starting motor 13 is transmitted to the engine 12, and the engine 12 is started. As a result, the vehicle is started, and the vehicle is driven using at least the power output from the engine 12 .

Next, in step S513, control unit 120 causes system main relay 61 to close. As a result, the main battery 21 and each device in the vehicle (specifically, the auxiliary device 51, the sub-battery 22, and the starting motor 13) are electrically connected.

After step S509 or step S513, the control flow shown in FIG. 5 ends.

As described above with reference to FIG. 5, when the sub-battery 22 is diagnosed as normal when the engine start request is made when the vehicle starts moving, the control unit 120 reduces the electric power stored in the main battery 21. The engine 12 is started by driving the starter motor 13 using the electric power stored in the sub-battery 22 without being used, and when the sub-battery 22 is diagnosed to be abnormal, the DCDC converter 42 The electric power supplied from the main battery 21 is used to drive the starting motor 13 to start the engine 12 . As a result, when the sub-battery 22 is abnormal, it is possible to prevent the start of the vehicle from being hindered due to insufficient power supplied to the starting motor 13 . Therefore, when the sub-battery 22 is abnormal, the startability can be appropriately secured.

Furthermore, as described above with reference to FIG. 5, when the sub-battery 22 is diagnosed to be abnormal when the engine start request is made when the vehicle starts moving, the control unit 120 starts the engine 12 and then , to perform fail-safe control. As a result, the charge amount or discharge amount of the sub-battery 22 can be reduced compared to the case where the sub-battery 22 is diagnosed as normal. It is possible to prevent the sub-battery 22 from being overcharged. Therefore, when the sub-battery 22 is abnormal, the vehicle can continue to run while protecting the sub-battery 22 .

[2-2. Second example]
Next, a second example of the overall flow of processing performed by the control device 100 will be described with reference to FIG.

FIG. 8 is a flow chart showing a second example of the overall flow of processing performed by the control device 100 . The control flow according to the second example shown in FIG. 8 is similar to the control flow according to the first example shown in FIG. This is the flow of processing related to time control, and is started when the power supply system 1 is stopped.

In the second example, as compared with the first example described with reference to FIG. , in that a process (specifically, step S601) for prohibiting starting of the engine 12 is added.

In the control flow according to the second example shown in FIG. 8, if YES is determined in step S503, unlike the control flow according to the first example shown in FIG. 5, the process proceeds to step S601.

If the determination in step S503 is YES, in step S601, control unit 120 determines whether or not the degree of abnormality of sub-battery 22 exceeds a standard. If it is determined that the degree of abnormality of the sub-battery 22 does not exceed the reference (step S601/NO), the process proceeds to step S505, and then step S507 in the same manner as the control flow according to the first example shown in FIG. And the process of step S509 is executed. On the other hand, if it is determined that the degree of abnormality of the sub-battery 22 exceeds the reference (step S601/YES), the control flow shown in FIG. 6 ends without executing the processes of steps S505, S507, and S509. .

When the degree of abnormality of the sub-battery 22 exceeds the reference, it corresponds to a case where the possibility of damaging the sub-battery 22 by supplying power to the sub-battery 22 is excessively high.

For example, when it is diagnosed that the sub-battery 22 is short-circuited in the diagnosis of the presence or absence of an abnormality in the sub-battery 22 in step S503, the control unit 120 sets the open end voltage of the sub-battery 22 to a reference voltage lower than the voltage threshold. If it is determined to be lower, it is determined that the degree of abnormality of the sub-battery 22 exceeds the standard. The reference voltage can be appropriately set according to the specifications of the sub-battery 22, for example.

Further, for example, when the sub-battery 22 is diagnosed to be degraded in the diagnosis of the presence or absence of an abnormality in the sub-battery 22 in step S503, the control unit 120 sets the criterion that the internal resistance of the sub-battery 22 is greater than the resistance threshold. When it is determined that the resistance is higher than the resistance, it is determined that the degree of abnormality of the sub-battery 22 exceeds the standard. The reference resistance can be appropriately set according to the specifications of the sub-battery 22, for example.

As described above, in the second example explained with reference to FIG. 22 exceeds the standard, the start of the engine 12 is prohibited. As a result, it is possible to avoid starting the vehicle using the power output from the engine 12 when the possibility of damaging the sub-battery 22 due to the supply of electric power to the sub-battery 22 is excessively high. Therefore, charging of the sub-battery 22 by electric power generated by the starting motor 13 driven by the engine 12 can be avoided. Therefore, the sub-battery 22 can be more appropriately protected when the sub-battery 22 becomes abnormal.

In the above, an example of the flow of processing performed by the control device 100 has been described with reference to each control flow shown in FIGS. not.

Specifically, an example of processing in the fail-safe control has been described above with reference to FIGS. Various types of processing can be used as the processing in the fail-safe control, as long as the control reduces the failure compared to the case where it is diagnosed as being present.

For example, in the fail-safe control, the control unit 120 is permitted to use the output of the DCDC converter 42 (that is, electric power supplied from the main battery 21 side to the sub-battery 22 side via the DCDC converter 42) in the HEV running mode. You may lower it compared with a case. Thereby, the charging amount of the sub-battery 22 by the electric power supplied from the main battery 21 via the DCDC converter 42 can be reduced.

Further, for example, in the fail-safe control, the control unit 120 may reduce the power generation amount of the starting motor 13 using the power output from the engine 12 compared to when the HEV traveling mode is permitted. . As a result, the amount of charge in charging the sub-battery 22 using the power output from the engine 12 can be reduced.

Also, for example, the control unit 120 may open the diagnostic relay 62 in the fail-safe control. As a result, the power supply through the sub-battery 22 and the diagnostic relay 62 is stopped, so that the amount of charge and the amount of discharge of the sub-battery 22 can be reduced.

Also, for example, the control unit 120 may limit or stop the function of the auxiliary machine 51 in the fail-safe control. As a result, the amount of discharge of sub-battery 22 to auxiliary device 51 can be reduced.

Further, in each control flow shown in FIG. 5 or FIG. 8, when it is determined that the sub-battery is normal (that is, when it is determined as NO in step S503), step S513 is performed after step S511 is performed. is performed, step S513 may be performed before step S511.

<3. Effect of power supply system>
Next, effects of the power supply system 1 according to the embodiment of the present invention will be described.

In the power supply system 1 according to the present embodiment, the control unit 120 operates in an HEV running mode in which the power of the engine 12 and the drive motor 11 is used for running, and in a state in which the engine 12 is stopped and the power of the drive motor 11 is used. It can be executed by switching to the EV driving mode in which the vehicle is driven by the vehicle. Further, the vehicle is started using the power output from the engine 12 . Further, when the sub-battery 22 is diagnosed to be normal when the engine start request is made when the vehicle starts moving, the control unit 120 does not use the power stored in the main battery 21, but the power stored in the sub-battery 22. is used to drive the starting motor 13 to start the engine 12 . On the other hand, when the sub-battery 22 is diagnosed to be abnormal when the engine start request is made when the vehicle starts moving, the control unit 120 uses the electric power supplied from the main battery 21 via the DCDC converter 42 to start the starting motor. 13 to start the engine 12, and then perform fail-safe control to reduce the charge amount or discharge amount of the sub-battery 22 compared to when the sub-battery 22 is diagnosed as normal.

As described above, when the sub-battery 22 is diagnosed to be abnormal when the engine is requested to start when the vehicle starts moving, the electric power supplied from the main battery 21 via the DCDC converter 42 is used to start the starting motor 13. By starting the engine 12 by driving, it is possible to prevent the start of the vehicle from being hindered due to insufficient electric power supplied to the starting motor 13 . Furthermore, as described above, when the sub-battery 22 is diagnosed to be abnormal when the engine start request is made when the vehicle starts moving, the vehicle starts running by executing the fail-safe control after starting the engine 12. It is possible to suppress overcharging of the sub-battery 22 in which an abnormality has occurred while avoiding the failure. Therefore, according to the power supply system 1 according to the present embodiment, it is possible to protect the sub-battery 22 and continue running the vehicle while appropriately ensuring startability when the sub-battery 22 is abnormal.

Further, in the power supply system 1 according to the present embodiment, when the sub-battery 22 is diagnosed to be abnormal when the engine start request is made when the vehicle starts moving, the control unit 120 determines that the degree of abnormality of the sub-battery 22 does not meet the standard. If it exceeds, it is preferable to prohibit the starting of the engine 12 . As a result, when the possibility of damage to the sub-battery 22 due to the supply of electric power to the sub-battery 22 is excessively high, the vehicle is prevented from being started using the power output from the engine 12. Since the charging of the sub-battery 22 can be avoided, the sub-battery 22 can be more appropriately protected when the sub-battery 22 becomes abnormal.

In the power supply system 1 according to the present embodiment, the control unit 120 prohibits the HEV running mode in the fail-safe control when the SOC of the main battery 21 is equal to or higher than the threshold (specifically, the first threshold). It is preferable that the EV driving mode is permitted when the SOC of the main battery 21 is lower than the threshold value (specifically, the first threshold value), and the HEV driving mode is permitted. As a result, charging of the sub-battery 22 using the power output from the engine 12 can be stopped. Charging can be suppressed appropriately. Further, when the cruising distance in the EV driving mode becomes excessively short, it is possible to avoid switching the driving mode to the EV driving mode, so that the continuation of the driving of the vehicle is more appropriately performed when the sub-battery 22 is abnormal. can be realized.

Furthermore, when the sub-battery 22 is abnormal, the HEV driving mode is prohibited and the driving mode is not switched to the HEV driving mode. can be done. Therefore, replacement of the sub-battery 22 by the driver can be encouraged.

In addition, in the power supply system 1 according to the present embodiment, if the sub-battery 22 is diagnosed to be abnormal at the time of the engine start request when the vehicle starts moving, the control unit 120 starts the engine 12 and then performs the main power supply. When the SOC of battery 21 is higher than a second threshold that is larger than the first threshold, it is preferable to permit the HEV running mode. As a result, when it becomes difficult to appropriately perform regenerative braking due to the large limitation of the electric power that can be charged to the main battery 21, the running mode is prevented from being switched to the EV running mode. can be done. Therefore, in such a case, it is possible to suppress the difficulty in appropriately controlling the behavior of the vehicle due to the switching of the driving mode to the EV driving mode. Continuations can be better implemented.

<4. Conclusion>
As described above, in the power supply system 1 according to the present embodiment, the control unit 120 can switch between the HEV running mode and the EV running mode. Further, the vehicle is started using the power output from the engine 12 . Further, when the sub-battery 22 is diagnosed to be normal when the engine start request is made when the vehicle starts moving, the control unit 120 does not use the power stored in the main battery 21, but the power stored in the sub-battery 22. is used to drive the starting motor 13 to start the engine 12 . On the other hand, when the sub-battery 22 is diagnosed to be abnormal when the engine start request is made when the vehicle starts moving, the control unit 120 uses the electric power supplied from the main battery 21 via the DCDC converter 42 to start the starting motor. 13 to start the engine 12, and then perform fail-safe control to reduce the charge amount or discharge amount of the sub-battery 22 compared to when the sub-battery 22 is diagnosed as normal. As a result, when the sub-battery 22 is abnormal, the start of the vehicle is prevented from being hindered due to a shortage of electric power supplied to the starting motor 13, and the vehicle is prevented from running. It is possible to suppress overcharging of the sub-battery 22 in which . Therefore, when the sub-battery 22 has an abnormality, it is possible to protect the sub-battery 22 and continue the running of the vehicle while appropriately ensuring startability.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or applications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

For example, processes described herein using flowcharts do not necessarily have to be performed in the order shown in the flowcharts. Also, some processing steps may be performed in parallel. Also, additional processing steps may be employed, and some processing steps may be omitted.

Further, for example, the configuration of the power supply system 1 as an example of the power supply system according to the present invention has been described above with reference to FIG. is not limited to

In addition, the power supply system according to the present invention has components added to the power supply system 1 shown in FIG. It may be a thing or the like.

1 Power supply system 5 Driving wheel 11 Driving motor 12 Engine 13 Starting motor 21 Main battery 22 Sub-battery 31 Transmission 41 Inverter 42 DCDC converter 51 Auxiliary machine 61 System main relay 62 Diagnostic relay 91 Main battery sensor 92 Sub-battery sensor 93 Vehicle speed sensor 100 Control device 110 Acquisition unit 120 Control unit 121 Motor control unit 122 Engine control unit 123 Relay control unit 124 Converter control unit 125 Diagnosis unit

Claims (4)

a drive motor;
engine and
a starting motor for starting the engine;
a main battery that stores electric power supplied to the driving motor;
a sub-battery that stores electric power supplied to the starting motor and is connected to the main battery via a DCDC converter capable of stepping down the electric power stored in the main battery;
A control unit capable of switching between an HEV driving mode in which driving is performed using the power of the engine and the driving motor and an EV driving mode in which driving is performed using the power of the driving motor with the engine stopped. a controller having
A vehicle comprising
The vehicle is started using power output from the engine,
The control unit
When it is determined that the sub-battery is normal when the engine is requested to start when the vehicle starts moving, the power stored in the sub-battery is used instead of the power stored in the main battery. starting the engine by driving a motor;
When the sub-battery is diagnosed to be abnormal at the time of the engine start request, the electric power supplied from the main battery via the DCDC converter is used to drive the starting motor to start the engine. , and then perform fail-safe control to reduce the charge amount or discharge amount of the sub-battery compared to when the sub-battery is diagnosed as normal;
vehicle . When the sub-battery is diagnosed to be abnormal at the time of the engine start request, the control unit prohibits the start of the engine if the degree of abnormality of the sub-battery exceeds a standard.
A vehicle according to claim 1 . In the fail-safe control, the control unit prohibits the HEV running mode and permits the EV running mode when the remaining capacity of the main battery is equal to or greater than a threshold, and the remaining capacity of the main battery is greater than the threshold. if low, allow the HEV driving mode;
A vehicle according to claim 1 or 2. When the threshold is the first threshold,
In the fail-safe control, the control unit permits the HEV running mode when the remaining capacity of the main battery is higher than a second threshold that is larger than the first threshold.
A vehicle according to claim 3.

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