JP7484562B2 - Hybrid vehicle control device - Google Patents

Description

The present invention relates to a control device for a hybrid vehicle.

Patent document 1 discloses a battery degradation diagnosis device that detects the battery terminal voltage before the alternator starts generating electricity and the battery charging current after the alternator starts generating electricity, and determines that the degree of battery degradation has reached a predetermined level when the detected terminal voltage is equal to or lower than a predetermined value and the detected charging current is equal to or lower than a predetermined value.

In a degradation diagnosis device that determines the degree of battery degradation based on the battery charging current, it is necessary to stably flow a certain amount of charging current in order to determine the degree of battery degradation.

JP 2005-127202 A

However, when the battery is disconnected from the degradation diagnosis device, for example when the battery is removed for maintenance, the result of the battery degradation degree determination is reset. When the battery is subsequently reconnected to the degradation diagnosis device, the battery degradation degree is determined again based on the battery charging current.

However, if the battery was fully charged before it was disconnected from the degradation diagnosis device, even if an attempt is made to determine the degree of battery degradation again based on the battery charging current as described above, it is not possible to pass a sufficient charging current through the battery. As a result, it is not possible to complete the determination of the degree of battery degradation.

While the battery deterioration level determination is pending, automatic engine shutdown is prohibited to avoid a situation in which the automatically stopped engine cannot be restarted. Therefore, if the battery deterioration level determination is not completed, the engine cannot be automatically stopped, resulting in poor fuel economy.

The battery deterioration diagnosis device described in Patent Document 1 leaves room for improvement because it does not take into consideration what to do when the battery deterioration level determination result is reset.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a control device for a hybrid vehicle that can perform battery degradation judgment even when the result of the battery degradation judgment is reset, and can prevent a deterioration in fuel efficiency.

In order to achieve the above-mentioned object, the present invention provides a control device for a hybrid vehicle including an engine and a motor as a driving source for transmitting power to driving wheels, a generator that generates electricity using the power of the engine, and a battery that is charged with the electricity generated by the generator, the control device including: a charging control unit that charges the battery with the generator so that the SOC of the battery becomes a target SOC; a deterioration determination unit that performs deterioration determination of the battery based on a charging current flowing to the battery; and a control unit that prohibits EV driving in which the engine is stopped and the motor is used as the driving source during the deterioration determination, and the deterioration determination unit is configured to set a deterioration determination flag to information indicating the completion of the deterioration determination when the deterioration determination is completed, set the target SOC to a first value while the deterioration determination flag is set to the information indicating the completion of the deterioration determination, and set the target SOC to a second value greater than the first value when the deterioration determination flag is reset .

The present invention provides a control device for a hybrid vehicle that can perform battery degradation determination even when the result of the battery degradation determination is reset, and can prevent deterioration of fuel economy.

FIG. 1 is a block diagram of a hybrid vehicle according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a power supply path for a low-voltage power pack of a hybrid vehicle according to one embodiment of the present invention, in which (a) is a circuit diagram when the engine is running, (b) is a circuit diagram when the engine is automatically stopped, and (c) is a circuit diagram when the second storage device is equal to or higher than the target SOC. FIG. 3 is a flowchart showing a flow of a switch changeover process executed by the low-voltage BMS of the hybrid vehicle according to one embodiment of the present invention. FIG. 4 is a timing chart showing a case where the result of the deterioration determination of the second power storage device is reset in a comparative example having a configuration in which the target SOC is not changed depending on whether the deterioration determination of the second power storage device has been completed. FIG. 5 is a timing chart showing a case where the result of the deterioration determination of the second power storage device is reset in the hybrid vehicle according to one embodiment of the present invention.

The control device for a hybrid vehicle according to one embodiment of the present invention is a control device for a hybrid vehicle that includes an engine and a motor as a drive source that transmits power to drive wheels, a generator that generates electricity using the power of the engine, and a battery that is charged by the electricity generated by the generator. The control device includes a deterioration determination unit that performs battery deterioration determination based on a charging current flowing through the battery while the battery is being charged by the generator so that the SOC of the battery becomes a target SOC, and a control unit that prohibits EV driving in which the engine is stopped and the motor is used as a drive source during the deterioration determination. The deterioration determination unit is characterized in that if the deterioration determination is completed, the target SOC is set to a first value, and if the deterioration determination is not completed, the target SOC is set to a second value greater than the first value. As a result, the control device for a hybrid vehicle according to one embodiment of the present invention can perform battery deterioration determination even if the result of the battery deterioration determination is reset, and can prevent fuel efficiency from deteriorating.

Below, a hybrid vehicle control device according to one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the hybrid vehicle 1 includes an engine 2, a transmission 3, a motor generator 4 as a motor, drive wheels 5, an HCU (Hybrid Control Unit) 10 that provides overall control of the hybrid vehicle 1, an ECM (Engine Control Module) 11 that controls the engine 2, a TCM (Transmission Control Module) 12 that controls the transmission 3, an ISGCM (Integrated Starter Generator Control Module) 13, an INVCM (Inverter Control Module) 14, a low-voltage BMS (Battery Management System) 15, and a high-voltage BMS 16. The engine 2 and the motor generator 4 form a drive source that transmits power to the drive wheels 5.

The engine 2 has multiple cylinders. In this embodiment, the engine 2 is configured to perform a series of four strokes for each cylinder, consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

An ISG (Integrated Starter Generator) 20 and a starter 21 are connected to the engine 2. The ISG 20 is connected to the crankshaft 18 of the engine 2 via a power transmission member 22 such as a belt or chain. The ISG 20 functions as an electric motor that rotates when power is supplied to rotate the engine 2, and also functions as a generator that converts the rotational force input from the crankshaft 18 into electricity, i.e., generates electricity using the power of the engine 2.

In this embodiment, the ISG 20 functions as an electric motor under the control of the ISGCM 13, restarting the engine 2 from a stopped state caused by the idling stop function. The ISG 20 can also assist the running of the hybrid vehicle 1 by functioning as an electric motor.

The starter 21 is configured to include a motor and a pinion gear (not shown). The starter 21 rotates the motor to rotate the crankshaft 18, thereby providing the engine 2 with a rotational force at the time of starting. In this way, the engine 2 is started by the starter 21, and is restarted by the ISG 20 from a stopped state caused by the idling stop function.

The transmission 3 changes the speed of the rotation output from the engine 2 and transmits it to the drive wheels 5 via the drive shaft 23 to drive the drive wheels 5. The transmission 3 includes a constant mesh type speed change mechanism 25 consisting of a parallel shaft gear mechanism, a clutch 26 consisting of a normally closed type dry clutch, a differential mechanism 27 as a reducer, and actuators 51 and 52.

The clutch 26 is provided between the transmission mechanism 25 and the engine 2, and is switched between engaged and disengaged to disconnect or connect the power transmission path between the drive wheels 5 and the engine 2.

The transmission 3 is configured as a so-called AMT (Automated Manual Transmission) and is configured to be able to establish multiple gear stages, including multiple forward gear stages and multiple reverse gear stages. In the transmission 3, the gear stages in the speed change mechanism 25 are changed by an actuator 52 controlled by the TCM 12, and the clutch 26 is engaged and disengaged by an actuator 51. The differential mechanism 27 transmits the power output by the speed change mechanism 25 to the drive shaft 23.

The motor generator 4 is connected to the differential mechanism 27 via a power transmission member 28 such as a chain. The motor generator 4 is connected to the drive shaft 23 via the differential mechanism 27. The motor generator 4 functions as an electric motor.

In this way, the hybrid vehicle 1 forms a parallel hybrid system that can use the power of both the engine 2 and the motor generator 4 to drive the vehicle, and is designed to run using the power output by at least one of the engine 2 and the motor generator 4.

The driving modes of the hybrid vehicle 1 include at least an HEV driving mode in which the driving force of the engine 2 and the motor generator 4 is transmitted to the drive shaft 23 to drive the hybrid vehicle 1, and an EV driving mode in which the driving force of only the motor generator 4 is transmitted to the drive shaft 23 to drive the hybrid vehicle 1. In the EV driving mode, the engine 2 is stopped and EV driving is performed, in which the vehicle runs using the motor generator 4 as a driving source.

The motor generator 4 also functions as a generator that generates electricity using the rotation of the drive wheels 5, and generates electricity as the hybrid vehicle 1 runs. Note that the motor generator 4 only needs to be connected to any point in the power transmission path from the engine 2 to the drive wheels 5 so that it can transmit power, and does not necessarily have to be connected to the differential mechanism 27.

The hybrid vehicle 1 includes a first power storage device 30, a low-voltage power pack 32 including a second power storage device 31 as a battery, a high-voltage power pack 34 including a third power storage device 33, a high-voltage cable 35, and a low-voltage cable 36.

The first storage device 30, the second storage device 31, and the third storage device 33 are composed of rechargeable secondary batteries. The first storage device 30 is composed of a lead battery. The second storage device 31 is a storage device with higher output and higher energy density than the first storage device 30.

The second storage device 31 is configured to be charged with power generated by the ISG 20, and can be charged in a shorter time than the first storage device 30. In this embodiment, the second storage device 31 is made of a lithium-ion battery. The state of the second storage device 31, such as its remaining capacity (hereinafter referred to as "SOC"), is managed by the low-voltage BMS 15. The second storage device 31 may also be a nickel-metal hydride battery.

The first storage battery 30 and the second storage battery 31 are low-voltage batteries in which the number of cells is set to generate an output voltage of approximately 12 V. The third storage battery 33 is, for example, a lithium-ion battery.

The third storage device 33 is a high-voltage battery in which the number of cells is set so as to generate a higher voltage than the first storage device 30 and the second storage device 31, and generates an output voltage of, for example, 100 V. The state of the third storage device 33, such as its SOC, is managed by the high-voltage BMS 16.

The hybrid vehicle 1 is provided with a general load 37 and a protected load 38 as electrical loads. The general load 37 and the protected load 38 are electrical loads other than the starter 21 and the ISG 20. In this embodiment, the protected load 38 constitutes an electrical load.

The protected load 38 is an electrical load that requires a constant stable power supply. This protected load 38 includes a stability control device that prevents skidding of the hybrid vehicle 1, an electric power steering control device that electrically assists the steering force of the steering wheel, and headlights. The protected load 38 also includes lamps and meters on the instrument panel, not shown, and a car navigation system.

The general loads 37 are electrical loads that do not require a stable power supply compared to the protected loads 38 and are used temporarily. The general loads 37 include, for example, windshield wipers (not shown) and an electric cooling fan that blows cooling air to the engine 2.

The low-voltage power pack 32 has a first switch 40, a second switch 41, and a low-voltage BMS 15 in addition to the second storage device 31. The first storage device 30 and the second storage device 31 are connected via a low-voltage cable 36 so as to be able to supply power to the starter 21, the ISG 20, the general load 37, and the protected load 38. The first storage device 30 and the second storage device 31 are electrically connected in parallel to the protected load 38.

The first switch 40 is provided in the low-voltage cable 36 between the second storage device 31 and the protected load 38. The opening and closing of the first switch 40 is controlled by the low-voltage BMS 15, and the first switch 40 is configured to electrically connect or disconnect the second storage device 31 and the protected load 38. When the first switch 40 is closed, the second storage device 31 and the protected load 38 are electrically connected. When the first switch 40 is opened, the second storage device 31 and the protected load 38 are electrically disconnected.

The second switch 41 is provided in the low-voltage cable 36 between the first storage device 30 and the protected load 38. The opening and closing of the second switch 41 is controlled by the low-voltage BMS 15. When the second switch 41 is closed, the first storage device 30 and the protected load 38 are electrically connected. When the second switch 41 is opened, the first storage device 30 and the protected load 38 are electrically disconnected.

The low-voltage BMS 15 controls the charging and discharging of the second storage device 31 and the power supply to the protected load 38 by controlling the opening and closing of the first switch 40 and the second switch 41.

As shown in FIG. 2(a), when the engine 2 is running, the low-voltage BMS 15 closes both the first switch 40 and the second switch 41 to supply the power generated by the ISG 20 to the first power storage device 30 and the second power storage device 31, respectively, to charge the first power storage device 30 and the second power storage device 31. At this time, the power generated by the ISG 20 is also supplied to the general load 37 and the protected load 38. In this embodiment, the first switch 40 and the second switch 41 constitute a switch.

As shown in FIG. 2(b), when the engine 2 is stopped due to idling stop, the low-voltage BMS 15 closes the first switch 40 and opens the second switch 41 to supply power from the high-output, high-energy-density second storage device 31 to the protected load 38. At this time, power is supplied to the general load 37 from the first storage device 30.

Furthermore, when the engine 2 is started by the starter 21, and when the engine 2 that has been stopped by idling stop control is restarted by the ISG 20, the low-voltage BMS 15 supplies power from the first storage device 30 to the starter 21 or the ISG 20 by closing the first switch 40 and opening the second switch 41. When the first switch 40 is closed and the second switch 41 is open, power is also supplied from the first storage device 30 to the general load 37.

As shown in FIG. 2(c), when the engine 2 is running and the SOC of the second storage device 31 is equal to or higher than the target SOC, the low-voltage BMS 15 opens the first switch 40 and closes the second switch 41 to avoid overcharging of the second storage device 31. As a result, the low-voltage BMS 15 electrically disconnects the second storage device 31 from the ISG 20 and the protected load 38, preventing the second storage device 31 from being charged.

As shown in FIG. 1, the second power storage device 31 is connected so that it can supply power to both the general load 37 and the protected load 38, but the first switch 40 and the second switch 41 are controlled by the low-voltage BMS 15 so that power is supplied preferentially to the protected load 38, which always requires a stable power supply.

The low-voltage BMS 15 may take into consideration the charge state (remaining capacity) of the first storage device 30 and the second storage device 31, as well as the operation requests of the general load 37 and the protected load 38, and may control the first switch 40 and the second switch 41 differently from the example described above, prioritizing stable operation of the protected load 38.

The high-voltage power pack 34 has an inverter 45, an INVCM 14, and a high-voltage BMS 16 in addition to the third power storage device 33. The high-voltage power pack 34 is connected to the motor generator 4 via a high-voltage cable 35 so as to be able to supply power to the motor generator 4.

The inverter 45, under the control of the INVCM 14, converts between the AC power applied to the high-voltage cable 35 and the DC power applied to the third power storage device 33. For example, when the INVCM 14 powers the motor generator 4, it converts the DC power discharged by the third power storage device 33 into AC power using the inverter 45 and supplies it to the motor generator 4.

When the motor generator 4 is in a regenerative mode, the INVCM 14 converts the AC power generated by the motor generator 4 into DC power using the inverter 45 and charges the third power storage device 33.

The HCU10, ECM11, TCM12, ISGCM13, INVCM14, low-voltage BMS15 and high-voltage BMS16 are each composed of a computer unit equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, etc., input ports and output ports.

The ROM of these computer units stores various constants, maps, etc., as well as programs for causing the computer units to function as the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, low-voltage BMS 15, and high-voltage BMS 16.

In other words, the CPU executes the programs stored in the ROM using the RAM as a working area, and these computer units function as the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, low-voltage BMS 15, and high-voltage BMS 16 in this embodiment, respectively.

In this embodiment, the ECM 11 is configured to execute idling stop control. In this idling stop control, the ECM 11 automatically stops the engine 2 when a predetermined stop condition is met, and drives the ISG 20 via the ISGCM 13 to restart the engine 2 when a predetermined restart condition is met. This prevents unnecessary idling of the engine 2, improving the fuel efficiency of the hybrid vehicle 1.

In this embodiment, the low-voltage BMS 15 charges the second storage device 31 by the ISG 20 when the engine 2 is running so that the SOC of the second storage device 31 becomes the target SOC. The target SOC is set to a different value depending on whether or not the deterioration determination of the second storage device 31, which will be described later, has been completed.

Specifically, when the deterioration determination of the second storage device 31 described later has been completed, the low-voltage BMS 15 sets the target SOC to X [%] as a first value. When the deterioration determination of the second storage device 31 described later has not been completed, the low-voltage BMS 15 sets the target SOC to Y [%] as a second value. Here, Y [%] is a value greater than X [%].

In this embodiment, the difference between X [%] and Y [%] (e.g., 5%) is set so that the amount of charging current for the second storage device 31 required to change the SOC of the second storage device 31 from X [%] to Y [%] is at least equal to or greater than the amount of charging current required to complete the deterioration determination of the second storage device 31.

As described above, while the second storage device 31 is being charged, the low-voltage BMS 15 is configured to determine the deterioration of the second storage device 31 based on the charging current flowing through the second storage device 31.

Specifically, the low-voltage BMS 15 can determine that the second storage device 31 has deteriorated if the integrated value of the charging current flowing through the second storage device 31 during a predetermined period from the start of charging of the second storage device 31 is equal to or less than a predetermined value. The low-voltage BMS 15 can make the above-mentioned determination because the internal resistance of the second storage device 31 increases as deterioration of the second storage device 31 progresses.

The low-voltage BMS 15 can determine that the second storage device 31 is not degraded if the integrated value of the charging current flowing through the second storage device 31 during a predetermined period from the start of charging of the second storage device 31 is not equal to or greater than a predetermined value, i.e., is greater than the predetermined value. In this embodiment, the low-voltage BMS 15 constitutes a degradation determination unit.

The low-voltage BMS 15 sets the degradation determination flag to, for example, "1" when the degradation determination of the second storage device 31 described above is completed, and sets the degradation determination flag to, for example, "0" when the degradation determination is incomplete.

When the connection between the low-voltage BMS 15 and at least one of the first and second power storage devices 30 and 31 is cut off, for example when at least one of the first and second power storage devices 30 and 31 is removed from the hybrid vehicle 1 for maintenance or the like, the low-voltage BMS 15 resets the above-mentioned deterioration determination flag to "0."

Therefore, for example, when the deterioration determination of the second storage device 31 has been completed (deterioration determination flag = 1), and at least one of the first storage device 30 and the second storage device 31 is removed from the hybrid vehicle 1, the low-voltage BMS 15 sets the deterioration determination flag to "0." The low-voltage BMS 15 may be configured to reset the deterioration determination flag when either the first storage device 30 or the second storage device 31 is removed.

When determining the deterioration of the second storage device 31, the low-voltage BMS 15 may use the average value of the charging current flowing through the second storage device 31 during a predetermined period from the start of charging of the second storage device 31. In this case, the low-voltage BMS 15 can determine that the second storage device 31 is deteriorated when the average value of the charging current is equal to or lower than a predetermined average value.

When the deterioration determination of the second storage device 31 has not been completed, the low-voltage BMS 15 closes the first switch 40 and the second switch 41 to electrically connect the second storage device 31 and the ISG 20. In this embodiment, the configuration of closing the first switch 40 and the second switch 41 when the deterioration determination of the second storage device 31 has not been completed as described above includes a configuration of closing the first switch 40 with the second switch 41 closed.

The hybrid vehicle 1 is provided with CAN communication lines 48, 49 for forming an in-vehicle LAN (Local Area Network) that conforms to standards such as CAN (Controller Area Network).

The HCU 10 is connected to the INVCM 14 and the high-voltage BMS 16 via a CAN communication line 48. The HCU 10, the INVCM 14, and the high-voltage BMS 16 transmit and receive signals such as control signals to and from each other via the CAN communication line 48.

The HCU 10 is connected to the ECM 11, the TCM 12, the ISGCM 13, and the low-voltage BMS 15 via a CAN communication line 49. The HCU 10, the ECM 11, the TCM 12, the ISGCM 13, and the low-voltage BMS 15 transmit and receive signals such as control signals to and from each other via the CAN communication line 49.

Connected to the HCU 10 are a wheel speed sensor 10a that detects the wheel speed of each wheel including the drive wheels 5, an accelerator opening sensor 10b that detects the amount of operation of an accelerator pedal (not shown) as an accelerator opening, a clutch stroke sensor 10c that detects the degree of engagement of the clutch 26, and a crank angle sensor 10d. The HCU 10 calculates the engine speed, which is the rotation speed of the engine 2, based on the detection information from the crank angle sensor 10d.

The wheel speed sensor 10a outputs a pulse signal that generates a pulse every time the wheel rotates a predetermined angle as a vehicle speed pulse. The HCU 10 calculates the vehicle speed of the hybrid vehicle 1 based on this vehicle speed pulse.

The HCU 10 prohibits EV driving when the degradation determination of the second power storage device 31 by the low-voltage BMS 15 has not been completed, when the degradation determination is in progress, or when the low-voltage BMS 15 determines that the second power storage device 31 is degraded. In other words, the HCU 10 prevents the driving mode of the hybrid vehicle 1 from being shifted to the EV driving mode.

The HCU 10 also prohibits EV driving if the SOC of at least one of the first power storage device 30 and the second power storage device 31 falls below a predetermined SOC.

As described above, in each situation in which EV driving is prohibited, automatic stopping of engine 2 during idling stop control is also prohibited.

Next, the flow of the switch switching process performed by the low-voltage BMS 15 will be described with reference to FIG. 3.

The switch switching process shown in FIG. 3 is executed repeatedly at a predetermined time interval while the second switch 41 is closed. Therefore, in this embodiment, the second switch 41 is assumed to be closed when executing the switch switching process shown in FIG. 3.

As shown in FIG. 3, the low-voltage BMS 15 determines whether the deterioration determination of the second storage device 31 has been completed (step S1). Specifically, the low-voltage BMS 15 determines whether the deterioration determination flag is set to "1".

If the low-voltage BMS 15 determines in step S1 that the deterioration determination of the second storage device 31 has been completed, it sets the target SOC of the second storage device 31 to X [%] (step S2) and transitions to step S4.

If the low-voltage BMS 15 determines in step S1 that the deterioration determination of the second storage device 31 has not been completed, it sets the target SOC of the second storage device 31 to Y [%] (step S3) and transitions to step S4.

In step S4, the low-voltage BMS 15 determines whether the SOC of the second storage device 31 is equal to or greater than the target SOC. If the low-voltage BMS 15 determines in step S4 that the SOC of the second storage device 31 is equal to or greater than the target SOC, it opens the first switch 40 (step S5) and ends the switch switching process. This prevents the second storage device 31 from being overcharged.

If the low-voltage BMS 15 determines in step S4 that the SOC of the second storage device 31 is not equal to or greater than the target SOC, i.e., is less than the target SOC, it closes the first switch 40 (step S6) and ends the switch switching process. This causes the second storage device 31 to be charged. If the deterioration determination of the second storage device 31 has not been completed, the deterioration determination of the second storage device 31 is performed based on the charging current flowing through the second storage device 31 during charging.

Next, referring to FIG. 5, the state of the first switch 40 and the transition of the SOC and charging current of the second storage device 31 when the result of the deterioration determination of the second storage device 31 is reset will be described in comparison with the comparative example shown in FIG. 4. The comparative example shown in FIG. 4 is configured in such a way that the target SOC is not changed depending on whether the deterioration determination of the second storage device has been completed or not.

As shown in FIG. 4, in the comparative example, the target SOC of the second storage device is set to Y [%] regardless of whether the deterioration determination of the second storage device has been completed. Therefore, in the comparative example, when the SOC of the second storage device reaches Y [%] at time t1 when the deterioration determination has been completed, the first switch is opened and the charging current flowing to the second storage device becomes zero.

After that, at time t2, when at least one of the first and second power storage devices is removed from the hybrid vehicle, for example for vehicle inspection, the deterioration determination flag is reset and the deterioration determination of the second power storage device becomes incomplete. At this time, the target SOC of the second power storage device remains at Y [%].

Next, at time t3, when the power storage device removed at time t2 is attached to the hybrid vehicle, the SOC of the second power storage device remains at Y [%] of the target SOC, so the first switch remains open. In other words, to prevent the second power storage device from being overcharged, the first switch is open and the second power storage device is not being charged.

For this reason, in the comparative example, after the power storage device is installed in the hybrid vehicle, a charging current cannot be passed to the second power storage device, and a deterioration determination for the second power storage device cannot be performed. As a result, in the hybrid vehicle according to the comparative example, the engine does not automatically stop, which not only deteriorates fuel efficiency but also causes a sense of discomfort to the driver.

In this case, it would be possible to determine the deterioration of the second storage device based on the discharge current from the second storage device, but because EV driving is also prohibited by prohibiting the automatic engine stop, it would be difficult to stably secure a certain level of discharge current.

In contrast, in the hybrid vehicle 1 according to this embodiment, as shown in FIG. 5, when the deterioration determination of the second power storage device 31 is completed, the target SOC of the second power storage device 31 is set to X [%].

Therefore, in the hybrid vehicle 1 according to this embodiment, when the SOC of the second storage device 31 reaches X [%] at time t1 after the deterioration determination is completed, the first switch 40 is opened and the charging current flowing through the second storage device 31 becomes zero.

After that, at time t2, when at least one of the first power storage device 30 and the second power storage device 31 is removed from the hybrid vehicle 1, for example for vehicle inspection, the deterioration determination flag is reset and the deterioration determination of the second power storage device 31 becomes incomplete.

Next, at time t3, when the power storage device removed at time t2 is attached to the hybrid vehicle 1, the target SOC of the second power storage device 31 is set to Y [%], which is greater than X [%], because the degradation determination flag is "0", indicating incompleteness. The target SOC of the second power storage device 31 may be set to Y [%] when the degradation determination flag is reset at time t2.

At time t3, the first switch 40 is closed and charging of the second storage device 31 is started. This causes a charging current to flow through the second storage device 31. Therefore, a deterioration determination of the second storage device 31 is made based on the charging current flowing through the second storage device 31 after time t3.

After that, at time t4, when the SOC of the second storage device 31 reaches Y [%], the first switch 40 is opened to prevent overcharging of the second storage device 31, and the deterioration determination of the second storage device 31 is completed.

In this way, in the hybrid vehicle 1 according to this embodiment, a charging current can be passed to the second power storage device 31 after the power storage device is attached to the hybrid vehicle 1, and a deterioration determination can be made for the second power storage device 31. As a result, in the hybrid vehicle 1 according to this embodiment, the engine 2 is automatically stopped, which prevents a deterioration in fuel economy and also prevents the driver from feeling uncomfortable.

As described above, the control device for the hybrid vehicle according to this embodiment is configured to increase the target SOC value of the second storage device 31 when the deterioration determination of the second storage device 31 has not been completed, compared to when the deterioration determination has been completed.

For this reason, in the control device for the hybrid vehicle according to this embodiment, the result of the deterioration determination of the second storage device 31 is reset while the second storage device 31 is maintained at the target SOC, and when the deterioration determination of the second storage device 31 becomes incomplete, the target SOC value of the second storage device 31 is set to a large value.

This allows a charging current to flow to the second storage device 31 in an incomplete degradation determination state after the result of the degradation determination for the second storage device 31 is reset while the second storage device 31 is maintained at the target SOC.

Therefore, the control device for the hybrid vehicle according to this embodiment can determine the deterioration of the battery even if the result of the deterioration determination of the second storage device 31 is reset while the second storage device 31 is maintained at the target SOC, and can prevent the fuel economy from deteriorating.

The control device for the hybrid vehicle according to this embodiment is also configured to control the first switch 40 and the second switch 41 to electrically connect the second storage device 31 and the ISG 20 when the deterioration determination of the second storage device 31 has not been completed.

With this configuration, the control device for the hybrid vehicle according to this embodiment can pass the current generated by the power generation of the ISG 20 as a charging current to the second storage device 31 when the deterioration determination of the second storage device 31 has not been completed.

The control device for the hybrid vehicle according to this embodiment also sets the difference between X [%] and Y [%] (e.g., 5%) so that the amount of charging current required to change the SOC of the second storage device 31 from X [%] to Y [%] is at least equal to or greater than the amount of charging current required to complete the deterioration determination of the second storage device 31.

With this configuration, the control device for the hybrid vehicle according to this embodiment can reliably complete the deterioration determination of the second storage device 31 before the SOC of the second storage device 31 reaches Y [%] from a state of X [%]. Therefore, even if the result of the deterioration determination of the second storage device 31 is reset while the SOC of the second storage device 31 is maintained at X [%], the deterioration determination of the second storage device 31 can be completed thereafter.

In this embodiment, an example is described in which an ISG20 is used as a generator, but an alternator may also be used as a generator.

Although an embodiment of the present invention has been disclosed, it is apparent that modifications may be made by one of ordinary skill in the art without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1 Hybrid vehicle 2 Engine 4 Motor generator (motor)
5 Drive wheel 10 HCU (control unit)
15 Low voltage BMS (deterioration determination unit)
20 ISG (generator)
30 First power storage device 31 Second power storage device (battery)
32 Low-voltage power pack 36 Low-voltage cable 37 General load 38 Protected load 40 First switch (switch)
41 Second switch (switch)

Claims (3)

An engine and a motor as a drive source that transmits power to drive wheels;
a generator that generates electricity using the power of the engine;
a battery that is charged by the power generated by the generator;
A control device for a hybrid vehicle comprising:
a charge control unit that charges the battery by the generator so that the SOC of the battery becomes a target SOC;
a deterioration determination unit that determines deterioration of the battery based on a charging current flowing through the battery;
a control unit that stops the engine and prohibits EV driving using the motor as the drive source during the deterioration determination,
The deterioration determination unit is
When the deterioration determination is completed, a deterioration determination flag is set to information indicating the completion of the deterioration determination, and while the deterioration determination flag is set to the information indicating the completion of the deterioration determination, the target SOC is set to a first value;
4. A control device for a hybrid vehicle, comprising: a control unit for controlling a hybrid vehicle, the control unit being operable to set the target SOC to a second value that is greater than the first value when the deterioration determination flag is reset . The hybrid vehicle includes:
a switch controlled by the deterioration determination unit to electrically connect or disconnect the battery and the generator;
Equipped with
The deterioration determination unit is
When the SOC of the battery is equal to or higher than the target SOC, the switch is controlled to electrically disconnect the battery and the generator;
2. The control device for a hybrid vehicle according to claim 1, wherein the control device controls the switch to electrically connect the battery and the generator when the deterioration determination is not completed. The control device for a hybrid vehicle according to claim 1 or 2, characterized in that the difference between the first value and the second value is set so that the amount of the charging current required to change the SOC of the battery from the first value to the second value is at least equal to or greater than the amount of the charging current required to complete the deterioration determination.

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