JP2021059265A - Charge control method for hybrid vehicle and charge control device for hybrid vehicle - Google Patents

Abstract

To prevent a situation in which an internal combustion engine does not start when set to an ignition-on state, in a hybrid vehicle that has been in an ignition-off state for a long time.SOLUTION: In an ignition-off state, power transmission (ExtraFeeding) from a first battery to a second battery is permitted in order to charge the second battery, until the SOC of the first battery reaches an SOC threshold value S (for example, 40%) obtained by adding a prescribed margin (for example, 4%) to a first SOC lower limit value A, so that an internal combustion engine can be started at start-up of the internal combustion engine after the lapse of a prescribed time T (for example, 60 days) following setting to the ignition-off state.SELECTED DRAWING: Figure 3

Description

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

For example, Patent Document 1 describes a motor / generator driven by an internal combustion engine and a motor that charges the electric power generated when the motor / generator operates as a generator and generates running power of a vehicle. It has a main battery that supplies electric power and an auxiliary battery that supplies electric power to auxiliary equipment of the vehicle, and when the ignition switch of the vehicle is turned off, the main battery supplies electric power to the auxiliary battery at regular intervals. The technology for charging the auxiliary battery is disclosed. In Patent Document 1, the internal combustion engine is started by supplying electric power from a main battery to a motor / generator and driving the motor / generator as a starter motor.

Japanese Unexamined Patent Publication No. 2006-174619

However, in Patent Document 1, for example, when the ignition switch of the vehicle is turned off for a long period of time, the amount of electric power supplied from the main battery to the auxiliary battery increases, and the amount of charge of the main battery becomes large. There is a risk that it will decrease.

Therefore, in Patent Document 1, when the ignition switch of the vehicle is turned on, the charge amount of the main battery may be insufficient and the internal combustion engine may not be started.

In the ignition off state, the vehicle allows power transmission from the first battery to the second battery and charges the second battery within a range in which the electric power required for starting the internal combustion engine can be left in the first battery. The internal combustion engine drives an electric motor for power generation to generate electricity. The electric motor for power generation charges the first battery with the generated electric power. The first battery supplies electric power to a drive electric motor that drives the drive wheels of the vehicle. The second battery supplies electric power to auxiliary machinery of the vehicle.

According to the present invention, the vehicle can avoid a state in which the internal combustion engine cannot be started due to insufficient charging of the first battery, and can suppress a decrease in SOC of the second battery after the ignition is turned off.

An explanatory view schematically showing a schematic configuration of a hybrid vehicle to which the present invention is applied. The explanatory view which shows typically the system structure of the control system of the hybrid vehicle to which this invention was applied. The characteristic diagram which showed the transition of SOC of the 1st battery and 2nd battery in the ignition off state by temperature. The flowchart which shows the control flow in the state which the hybrid vehicle to which this invention is applied is the ignition off.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram schematically showing a schematic configuration of a hybrid vehicle 1 to which the present invention is applied. FIG. 2 is an explanatory diagram schematically showing the system configuration of the control system of the hybrid vehicle 1 to which the present invention is applied.

First, a schematic configuration of the hybrid vehicle 1 will be described with reference to FIG. As shown in FIG. 1, the hybrid vehicle 1 supplies electric power to the drive motor 3 via the drive wheels 2 of the vehicle, the drive motor 3 for rotationally driving the drive wheels 2, the terminal 4, and the first inverter 5. The first battery 6, the electric motor 8 for power generation that supplies and charges the first battery 6 via the second inverter 7 and the terminal 4, and the internal combustion engine 9 that drives the electric motor 8 for power generation to generate electric power. It has a second battery 11 capable of charging the electric power of the first battery 6 supplied via the terminal 4 and the DC / DC converter 10. The terminal 4 is, for example, a terminal of the first battery 6.

The drive wheels 2 are rotationally driven by using the drive electric motor 3 as a drive source. The rotation of the drive motor 3 is transmitted to the drive wheels 2 via the first reduction mechanism 12 and the differential gear 13. The first deceleration mechanism 12 decelerates the rotation of the drive electric motor 3 to increase the motor torque and secure the traveling drive torque.

The drive electric motor 3 includes, for example, a synchronous motor using a permanent magnet in the rotor. The drive electric motor 3 is a drive source of the hybrid vehicle 1 and is driven by AC power from the first inverter 5. Further, the drive electric motor 3 functions as a generator when the vehicle is decelerated. That is, the drive electric motor 3 can charge the first battery 6 via the first inverter 5 and the terminal 4 using the regenerative energy at the time of deceleration of the vehicle as electric power.

The first inverter 5 can convert the electric power generated by the drive electric motor 3 into DC electric power and supply it to the first battery 6. Further, the first inverter 5 can convert the DC power output from the first battery 6 into AC power and supply it to the drive electric motor 3.

The first battery 6 as a high-voltage battery is made of, for example, a lithium ion battery, and has a higher voltage and a larger capacity than the second battery 11. The first battery 6 is a secondary battery capable of charging the electric power generated by the electric motor 8 for power generation and the electric motor 3 for driving as DC electric power. When the power generation electric motor 8 functions as the starter motor of the internal combustion engine 9, the first battery 6 supplies the charged electric power to the power generation electric motor 8 via the terminal 4 and the second inverter 7.

The first battery 6 is controlled so that the SOC is at least a predetermined first SOC target value P1 (for example, 50%) or more when the hybrid vehicle 1 is in the ignition on state (the ignition switch of the hybrid vehicle 1 is on). .. Here, SOC represents the state of charge of the battery, and the value changes between 0 and 100 (%).

The electric motor 8 for power generation includes, for example, a synchronous motor using a permanent magnet in the rotor. The power generation electric motor 8 converts the rotational energy generated in the internal combustion engine 9 into electric energy, and can supply the rotational energy to the first battery 6 via the second inverter 7 and the terminal 4. The generated power can be supplied to the drive motor 3 via the second inverter 7 and the first inverter 5. Further, the power generation electric motor 8 can supply the generated electric power to the second battery 11 via the second inverter 7, the terminal 4, and the DC / DC converter 10.

The rotation of the crankshaft 15 of the internal combustion engine 9 is transmitted to the electric motor 8 for power generation via the second speed reduction mechanism 14. The power generation electric motor 8 also functions as a starter motor when the internal combustion engine 9 is started. When the electric motor 8 for power generation is used as a starter motor for an internal combustion engine 9, electric power is supplied from a first battery 6 via a terminal 4 and a second inverter 7.

The internal combustion engine 9 is a so-called reciprocating internal combustion engine that converts the reciprocating linear motion of the piston (not shown) into the rotational motion of the crankshaft 15 and extracts it as power.

The second inverter 7 can convert the electric power generated by the electric motor 8 for power generation into DC electric power and supply it to the first battery 6. Further, the second inverter 7 can convert the DC power output from the first battery 6 into AC power and supply it to the power generation motor 8.

When the DC / DC converter 10 supplies electric power from the first battery 6 to the second battery 11 via the terminal 4, the second battery generates electric power generated by the drive electric motor 3 and the electric power generator 8 via the terminal 4. When the battery 11 is supplied, the voltage is converted (decreased) so as to be a voltage suitable for the second battery 11.

The second battery 11 as a light electric battery is made of, for example, a lead storage battery, and has a lower voltage and a smaller capacity than the first battery 6. The second battery 11 is a secondary battery in which the electric power from the first battery 6 is charged via the terminal 4 and the DC / DC converter 10. The second battery 11 supplies electric power to low-voltage (for example, 12 V) in-vehicle electrical components (for example, auxiliary equipment such as computers, relays, lamps, and air conditioners constituting various controllers). The second battery 11 is controlled so that the SOC becomes a predetermined second SOC target value P2 (for example, 85%) in the ignition on state.

When there is no power transmission from the first battery 6 after the ignition of the hybrid vehicle 1 is turned off (the ignition switch of the hybrid vehicle 1 is turned off), the second battery 11 has a predetermined time T (T) set in advance after the ignition of the hybrid vehicle 1 is turned off. For example, 60 days), the SOC has a capacity below a predetermined second SOC lower limit value B. Further, in the case where the second battery 11 receives power from the first battery 6 after the ignition of the hybrid vehicle 1 is turned off, the SOC of the second battery 11 is the second SOC even if a preset predetermined time T elapses after the ignition of the hybrid vehicle 1 is turned off. It has a capacity that is equal to or higher than the lower limit value B. The second SOC lower limit value B is the lower limit value of the deterioration suppression SOC range, which is the SOC range for suppressing the deterioration of the second battery 11.

The second battery 11 may be charged with the electric power generated by the drive electric motor 3 at the time of regeneration in addition to the electric power of the first battery 6 when the ignition of the hybrid vehicle 1 is off.

The schematic configuration of the control system of the hybrid vehicle 1 will be described with reference to FIG.

The hybrid controller 21 implements various integrated controls based on input signals from the electrical component controller 22, the first battery controller 23, the engine controller 24, and the like. The hybrid controller 21 is connected to the electrical component controller 22, the first battery controller 23, and the engine controller 24 via a CAN communication line capable of exchanging information in both directions.

The electrical component controller 22 controls the power supply to various electrical components in the vehicle, and outputs the automatic charging execution request signal (Extra Feeding execution request signal) and the degree of deterioration of the second battery 11 to the hybrid controller 21.

The automatic charging execution request signal is output at predetermined time intervals (for example, every 24 hours) after the ignition is turned off by the internal timer of the electrical component controller 22 or the like.

The degree of deterioration of the second battery 11 can be determined from, for example, the internal resistance of the second battery 11. The internal resistance of the second battery 11 increases as it deteriorates. The internal resistance of the second battery 11 increases as the current value of the second battery 11 becomes higher than the original current value (for example, when new). The degree of deterioration of the second battery 11 increases as the current value of the second battery 11 becomes higher than the original current value (for example, when the battery is new). That is, the electrical component controller 22 determines, for example, that the higher the current value of the second battery 11 is than the initial current value, the greater the degree of deterioration of the second battery 11. The capacity of the second battery 11 decreases as it deteriorates as compared with when it is new.

When the ignition is on, the electrical component controller 22 calculates the degree of deterioration of the second battery 11 at predetermined time intervals and outputs it to the hybrid controller 21. In the ignition off state, the electrical component controller 22 calculates the degree of deterioration of the second battery 11 at the timing when the automatic charging execution request signal is output, and outputs the deterioration degree to the hybrid controller 21.

The first battery controller 23 manages the SOC of the first battery 6, the remaining charge, the temperature of the first battery 6, and the like.

When the ignition is on, the first battery controller 23 outputs the SOC of the first battery 6 and the temperature of the first battery 6 to the hybrid controller 21 at predetermined time intervals. In the ignition off state, the first battery controller 23 outputs the SOC of the first battery 6 and the temperature of the first battery 6 to the hybrid controller 21 at the timing when the automatic charging execution request signal is output. ..

The engine controller 24 performs start control of the internal combustion engine 9, fuel injection control, ignition control, fuel cut control, idle rotation control, and the like based on various input information from various sensors and the like. Signals from various sensors that detect the temperatures of the lubricating oil and cooling water of the internal combustion engine 9, the outside air temperature, and the like are input to the engine controller 24.

When the ignition is on, the engine controller 24 outputs the temperatures of the lubricating oil and cooling water of the internal combustion engine 9 and the outside air temperature to the hybrid controller 21 at predetermined time intervals. When the ignition is off, the engine controller 24 outputs the temperature of the lubricating oil and cooling water of the internal combustion engine 9 and the outside air temperature to the hybrid controller 21 at the timing when the automatic charging execution request signal is output. ing.

The hybrid controller 21 has an automatic charging execution determination unit (Extra Feeding execution determination unit), and determines whether or not to charge the second battery 11 with the electric power from the first battery 6.

When the hybrid controller 21 determines that the second battery 11 may be charged with the electric power of the first battery 6, DC / DC is used to transmit power (Extra Feeding) from the first battery 6 to the second battery 11. The start request (Extra Feeding DCDC start request) of the converter 10 is output, and the high power relay on command and the DC / DC converter on command are output by the relay sequence using the electromagnetic relay as a switch. Information regarding the operating state of the DC / DC converter 10 is fed back to the electrical component controller 22.

In the ignition-on state, the hybrid controller 21 has, for example, the first battery 6 when the SOC of the first battery 6 is equal to or higher than the first SOC target value P1 and the SOC of the second battery 11 is less than the second SOC target value P2. It is determined that the second battery 11 may be charged with the electric power of.

The second battery 11 is controlled to have the second SOC target value P2 in the ignition on state, but when the ignition is off (the ignition switch of the hybrid vehicle 1 is off), the dark current (standby current) and self-discharge are reached. The SOC will decrease due to the discharge.

Therefore, the hybrid controller 21 determines whether or not to charge the second battery 11 with electric power from the first battery 6 every predetermined time (for example, every 24 hours) after the ignition is turned off, and if necessary, charges the second battery 11. It is charging.

However, in the hybrid vehicle 1, when the second battery 11 is charged with the electric power of the first battery 6 according to the SOC of the second battery 11 in the ignition off state, the SOC of the first battery 6 is excessively lowered and is used for power generation. When the electric motor 8 starts the internal combustion engine 9, the electric power supplied from the first battery 6 to the electric power generation electric motor 8 is insufficient, and there is a possibility that the internal combustion engine 9 cannot be started when the ignition is turned on.

Therefore, the hybrid controller 21 as a control unit transmits power from the first battery 6 to the second battery 11 within a range in which the electric power required for starting the internal combustion engine 9 can be left in the first battery 6 in the ignition off state. Extra Feeding) is allowed to charge the second battery 11.

That is, in the ignition off state, the hybrid controller 21 is the lower limit value of the SOC range in which the SOC of the first battery 6 when starting the internal combustion engine 9 can supply the electric power required to start the internal combustion engine 9. The second battery 11 is charged by permitting power transmission (Extra Feeding) from the first battery 6 to the second battery 11 within a range of 1 SOC lower limit A (for example, 36%) or more.

More specifically, the hybrid controller 21 can start the internal combustion engine 9 when the internal combustion engine 9 is started after a lapse of a predetermined time T after the ignition is turned off in the ignition off state, so that the first battery can be started. Transmission (Extra Feeding) from the first battery 6 to the second battery 11 until the SOC of 6 reaches the SOC threshold S (for example, 40%) obtained by adding a predetermined margin (for example, 4%) to the first SOC lower limit value A. Allow and charge the second battery 11.

That is, regardless of the temperature of the first battery 6, the hybrid controller 21 does not cause the SOC of the first battery 6 to fall below the first SOC lower limit value A even if a predetermined time T elapses without the ignition being turned on after the ignition is turned off. In addition, after the ignition is turned off, transmission from the first battery 6 to the second battery 11 (Extra Feeding) is repeatedly permitted until the SOC of the first battery 6 reaches the SOC threshold S obtained by adding a predetermined margin to the first SOC lower limit value A. To do.

In other words, when the first battery 6 cannot secure the SOC that can supply the electric power required to start the internal combustion engine 9 after a lapse of a predetermined time T after the ignition is turned off, the hybrid controller 21 is the first battery 6 to the first. 2 Prohibits power transmission (Extra Feeding) to the battery 11.

After the ignition is turned off, the hybrid controller 21 determines whether or not power transmission (Extra Feeding) can be performed from the first battery 6 to the second battery 11 at predetermined time intervals (for example, every 24 hours), and determines the second battery 11 each time. Charge for hours (eg 1 minute). That is, the hybrid controller 21 charges the second battery 11 by repeatedly permitting power transmission from the first battery 6 to the second battery 11 within the startable range of the internal combustion engine 9.

The first SOC lower limit value A, which is the SOC required for the first battery 6 when the internal combustion engine 9 is started, is the rotation speed of the power generation motor 8 when the power generation motor 8 is used as a starter, and the internal combustion engine 9 is rotated. It can be calculated from the resistance value and the electric power calculated by using.

The resistance value when rotating the internal combustion engine 9 can be calculated from the friction of the internal combustion engine 9, the viscosity of the lubricating oil, and the like.

As a result, the hybrid vehicle 1 can avoid a state in which the internal combustion engine 9 cannot be started due to insufficient charging of the first battery 6, and can suppress a decrease in SOC of the second battery 11 after the ignition is turned off. Further, the hybrid vehicle 1 can be miniaturized by reducing the capacity of the second battery 11.

That is, in the hybrid vehicle 1, the second battery can be started while the internal combustion engine 9 can be started for a predetermined period after the ignition is turned off and the deterioration of the second battery 11 due to over-discharging can be prevented. The capacity of the second battery 11 can be reduced to reduce the size of the second battery 11.

In order to improve the accuracy of the remaining battery level of the first battery 6 required for starting the internal combustion engine 9, the hybrid controller 21 determines the temperature of the first battery 6, the temperature of the lubricating oil and cooling water of the internal combustion engine 9, and the outside temperature. The value of the first SOC lower limit value A may be corrected, and these factors may be added to determine whether or not transmission (Extra Feeding) from the first battery 6 to the second battery 11 is possible.

Even if the hybrid controller 21 corrects so that the lower the temperature of the first battery 6 becomes higher, the first SOC lower limit value A becomes higher, and the higher the temperature of the first battery 6 becomes, the first SOC lower limit value A becomes lower. Good.

The first battery 6 requires a higher SOC to obtain the same power at lower temperatures.

As a result, the hybrid vehicle 1 can accurately avoid a state in which the internal combustion engine 9 cannot be started due to insufficient charging of the first battery 6 according to the temperature of the first battery 6. More specifically, the hybrid vehicle 1 permits power transmission from the first battery 6 to the second battery 11 within the startable range of the internal combustion engine 9 in consideration of the temperature of the first battery 6, so that the first battery 6 can be accurately transmitted. It is possible to avoid a state in which the internal combustion engine 9 cannot be started due to insufficient charging.

The hybrid controller 21 may correct the first SOC lower limit value A to be higher as the outside air temperature is lower, and may be corrected so that the first SOC lower limit value A is lower as the outside air temperature is higher.

The friction of the internal combustion engine 9 becomes smaller as the outside air temperature rises because the viscosity of the lubricating oil decreases.

As a result, the hybrid vehicle 1 can accurately avoid a state in which the internal combustion engine 9 cannot be started due to insufficient charging of the first battery 6 according to the outside air temperature. More specifically, the hybrid vehicle 1 permits power transmission from the first battery 6 to the second battery 11 within the startable range of the internal combustion engine 9 in consideration of the outside air temperature. It is possible to avoid a state in which the engine 9 cannot be started.

The hybrid controller 21 may correct the first SOC lower limit value A to be higher as the temperature of the lubricating oil is lower, and may be corrected so that the first SOC lower limit value A is lower as the temperature of the lubricating oil is higher.

The friction of the internal combustion engine 9 becomes smaller as the temperature of the lubricating oil increases because the viscosity of the lubricating oil decreases.

As a result, the hybrid vehicle 1 can accurately avoid a state in which the internal combustion engine 9 cannot be started due to insufficient charging of the first battery 6 according to the temperature of the lubricating oil. More specifically, the hybrid vehicle 1 permits power transmission from the first battery 6 to the second battery 11 within the startable range of the internal combustion engine 9 in consideration of the temperature of the lubricating oil, so that the charging of the first battery 6 is insufficient with high accuracy. Therefore, it is possible to avoid a state in which the internal combustion engine 9 cannot be started.

The hybrid controller 21 may correct the first SOC lower limit value A to be higher as the cooling water temperature is lower, and may be corrected so that the first SOC lower limit value A is lower as the cooling water temperature is higher.

The friction of the internal combustion engine 9 decreases as the temperature of the cooling water increases because the viscosity of the lubricating oil decreases.

As a result, the hybrid vehicle 1 can accurately avoid a state in which the internal combustion engine 9 cannot be started due to insufficient charging of the first battery 6 according to the temperature of the cooling water. More specifically, the hybrid vehicle 1 permits power transmission from the first battery 6 to the second battery 11 within the startable range of the internal combustion engine 9 in consideration of the temperature of the cooling water, so that the charging of the first battery 6 is insufficient with high accuracy. Therefore, it is possible to avoid a state in which the internal combustion engine 9 cannot be started.

Further, the hybrid controller 21 may correct the first SOC lower limit value A according to the capacity change of the second battery 11. Specifically, the lower the deterioration degree of the second battery 11 is corrected so that the first SOC lower limit value A becomes higher, and the lower the deterioration degree of the second battery 11 is corrected so that the first SOC lower limit value A becomes lower. You may do so.

As a result, the hybrid vehicle 1 can accurately avoid a state in which the internal combustion engine 9 cannot be started due to insufficient charging of the first battery 6 according to the degree of deterioration of the second battery 11. More specifically, the hybrid vehicle 1 permits power transmission from the first battery 6 to the second battery 11 within the startable range of the internal combustion engine 9 in consideration of the degree of deterioration of the second battery 11, so that the first battery 6 can be accurately performed. It is possible to avoid a state in which the internal combustion engine 9 cannot be started due to insufficient charging.

When the bonnet (or Hood, rear tailgate, back door) of the hybrid vehicle 1 is open, the hybrid controller 21 transmits power from the first battery 6 to the second battery 11 (Extra Feeding) in the ignition off state. May be prohibited.

FIG. 3 is a characteristic diagram showing the transition of SOC of each battery 6 and 11 by temperature due to power transmission (Extra Feeding) from the first battery 6 to the second battery 11 in the ignition off state and discharge in the ignition off state. .. In FIG. 3, power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed every predetermined period (for example, every 24 hours). Here, the discharge in the first battery 6 is self-discharge, and the discharge in the second battery 11 is discharge due to dark current and self-discharge.

The first SOC lower limit value A is the lower limit of the driveable SOC range (range outside the NG region) in which the first battery 6 can drive the power generation electric motor 8 to drive the internal combustion engine 9. The second SOC lower limit value B is the lower limit of the deterioration suppression SOC range (range outside the NG region) that suppresses the deterioration of the second battery 11 due to dark current discharge and self-discharge.

The first SOC lower limit value A in FIG. 3 is such that the internal combustion engine 9 can be started even after a predetermined time T set in advance has elapsed without the ignition being turned on after the ignition of the hybrid vehicle 1 is turned off. It is set to include a margin.

The characteristic lines L1 to L4 relating to the first battery 6 show the transition of the SOC of the first battery 6 in the ignition off state due to the transmission (Extra Feeding) from the first battery 6 to the second battery 11 and the self-discharge.

The characteristic lines L5 to L8 relating to the second battery 11 show the transition of the SOC of the second battery 11 in the ignition off state due to the transmission (Extra Feeding) from the first battery 6 to the second battery 11 and the dark current discharge and self-discharge. Shown.

The characteristic line L9 relating to the second battery 11 shows the change in SOC of the second battery 11 due to dark current discharge and self-discharge after the ignition is turned off. That is, the characteristic line L9 is a comparative example showing the transition of the SOC of the second battery 11 when the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is not performed after the ignition is turned off.

The characteristic line L1 shown by a solid line in FIG. 3 shows the transition of the SOC of the first battery 6 when the temperature of the first battery 6 is the first predetermined temperature H1 (for example, about 40 ° C.). When the temperature of the first battery 6 is the first predetermined temperature H1, the SOC of the first battery 6 reaches the SOC threshold value S at time t1, and power transmission (Extra Feeding) to the second battery 11 is not performed after time t1. ..

When the temperature of the first battery 6 is the first predetermined temperature H1, the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed for a predetermined time (for example, every 24 hours) until the time t1. 1 minute) It will be carried out.

The characteristic line L2 shown by the broken line in FIG. 3 shows the transition of the SOC of the first battery 6 when the temperature of the first battery 6 is lower than the first predetermined temperature H1 and the second predetermined temperature H2 (for example, about 25 ° C.). Shown. When the temperature of the first battery 6 is lower than the first predetermined temperature H1 and the second predetermined temperature H2, the SOC of the first battery 6 becomes the SOC threshold S at the time t2 later than the time t1, and the first battery 6 becomes the second after the time t2. 2 No power transmission (Extra Feeding) is performed to the battery 11.

When the temperature of the first battery 6 is the second predetermined temperature H2, the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed for a predetermined time (for example, every 24 hours) until time t2. 1 minute) It will be carried out.

The characteristic line L3 shown by the alternate long and short dash line in FIG. 3 is the transition of the SOC of the first battery 6 when the temperature of the first battery 6 is lower than the second predetermined temperature H2 and the third predetermined temperature H3 (for example, about 0 ° C.). Is shown. When the temperature of the first battery 6 is lower than the second predetermined temperature H2 and the third predetermined temperature H3, the SOC of the first battery 6 becomes the SOC threshold S at the time t3 later than the time t2, and the first battery 6 becomes the second after the time t3. 2 No power transmission (Extra Feeding) is performed to the battery 11.

When the temperature of the first battery 6 is the third predetermined temperature H3, the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed for a predetermined time (for example, every 24 hours) until the time t3. 1 minute) It will be carried out.

The characteristic line L4 shown by the chain double-dashed line in FIG. 3 is the SOC of the first battery 6 when the temperature of the first battery 6 is lower than the third predetermined temperature H3 and the fourth predetermined temperature H4 (for example, about −10 ° C.). Shows the transition of. When the temperature of the first battery 6 is lower than the fourth predetermined temperature H4 and the fourth predetermined temperature H4, the SOC of the first battery 6 becomes the SOC threshold S at the time t4 later than the time t3, and the SOC becomes the SOC threshold S after the time t4. 2 No power transmission (Extra Feeding) is performed to the battery 11.

When the temperature of the first battery 6 is the fourth predetermined temperature H4, the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed for a predetermined time (for example, every 24 hours) until the time t4. 1 minute) It will be carried out.

As shown in FIG. 3, the SOC threshold value S is such that the SOC of the first battery 6 is equal to or higher than the first SOC lower limit value A even after a predetermined time T has elapsed since the ignition was turned off, regardless of the temperature of the first battery 6. Is set to be.

Since the first battery 6 keeps the SOC at the first SOC lower limit value A or more even after the preset predetermined time T elapses after the ignition is turned off, the higher the battery temperature is, the more the first battery 6 is transferred to the second battery 11 after the ignition is turned off. The period of transmission (Extra Feeding) is shortened.

The characteristic line L5 shown by a solid line in FIG. 3 shows the transition of the SOC of the second battery 11 when the temperature of the second battery 11 is the first predetermined temperature H1 (for example, about 40 ° C.). When the temperature of the second battery 11 is the first predetermined temperature H1, the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed for a predetermined time (for example, every 24 hours) until the time t1. 1 minute) It will be carried out.

When the temperature of the second battery 11 is the first predetermined temperature H1, the second battery 11 has an SOC in which the power transmission (Extra Feeding) from the first battery 6 and the dark current discharge and the self-discharge are balanced until the time t1. It is maintained at the second SOC target value P2. Further, when the temperature of the second battery 11 is the first predetermined temperature H1, the SOC of the second battery 11 is lowered by dark current discharge and self-discharge after time t1.

The characteristic line L6 shown by the broken line in FIG. 3 shows the transition of the SOC of the second battery 11 when the temperature of the second battery 11 is lower than the first predetermined temperature H1 and the second predetermined temperature H2 (for example, about 25 ° C.). Shown. When the temperature of the second battery 11 is the second predetermined temperature H2, the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed every predetermined time (for example, every 24 hours) until the time t2, which is later than the time t1. ) For a predetermined time (for example, 1 minute).

When the temperature of the second battery 11 is the second predetermined temperature H2, the second battery 11 has an SOC in which the power transmission (Extra Feeding) from the first battery 6 and the dark current discharge and the self-discharge are balanced until time t2. It is maintained at the second SOC target value P2. Further, when the temperature of the second battery 11 is the second predetermined temperature H2, the SOC of the second battery 11 is lowered by dark current discharge and self-discharge after time t2.

The characteristic line L7 shown by the alternate long and short dash line in FIG. 3 shows the transition of the SOC of the second battery 11 when the temperature of the second battery 11 is lower than the second predetermined temperature H2 and the third predetermined temperature H3 (for example, about 0 ° C.). Is shown. When the temperature of the second battery 11 is the third predetermined temperature H3, the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed every predetermined time (for example, every 24 hours) until the time t3, which is later than the time t2. ) For a predetermined time (for example, 1 minute).

When the temperature of the second battery 11 is the third predetermined temperature H3, the SOC of the second battery 11 is the second SOC target value due to power transmission (Extra Feeding) from the first battery 6 and dark current discharge and self-discharge until time t3. It is gradually decreasing from P2. Further, when the temperature of the second battery 11 is the third predetermined temperature H3, the SOC of the second battery 11 is lowered by dark current discharge and self-discharge after time t3.

The characteristic line L8 shown by the alternate long and short dash line in FIG. 3 is the SOC of the second battery 11 when the temperature of the second battery 11 is lower than the third predetermined temperature H3 and the fourth predetermined temperature H4 (for example, about −10 ° C.). Shows the transition of. When the temperature of the second battery 11 is the fourth predetermined temperature H4, the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed every predetermined time (for example, every 24 hours) until the time t4, which is later than the time t3. ) For a predetermined time (for example, 1 minute).

When the temperature of the second battery 11 is the fourth predetermined temperature H4, the SOC of the second battery 11 is the second SOC target value due to power transmission (Extra Feeding) from the first battery 6 and dark current discharge and self-discharge until time t4. It is gradually decreasing from P2. Further, when the temperature of the second battery 11 is the fourth predetermined temperature H4, the SOC of the second battery 11 is lowered by dark current discharge and self-discharge after the time t4.

By performing power transmission (Extra Feeding) from the first battery 6 after the ignition is turned off, the second battery 11 has a second SOC lower limit even if a preset predetermined time T elapses after the ignition is turned off. The capacity is not less than the value B. Further, when the second battery 11 does not perform power transmission (Extra Feeding) from the first battery 6 after the ignition is turned off, the SOC becomes the second SOC lower limit value when a preset predetermined time T elapses after the ignition of the hybrid vehicle 1 is turned off. The capacity is less than B.

FIG. 4 is a flowchart showing a control flow in a state where the hybrid vehicle 1 of the above-described embodiment is ignition off.

In step S1, it is determined whether or not a predetermined time has elapsed since the ignition was turned off. More specifically, in step S1, every time a predetermined time (for example, 24 hours) elapses after the ignition is turned off, it is determined that the predetermined time has elapsed. If it is determined that a predetermined time has elapsed since the ignition was turned off in step S1, the process proceeds to step S2. If it is determined that the predetermined time has not elapsed since the ignition was turned off in step S1, the current routine is terminated.

In step S2, the system is automatically started and communication via the CAN communication line described above is restarted (CAN Wake UP command). That is, the hybrid vehicle 1 automatically starts a part of the system (CAN Wake UP command) at each timing when a predetermined time (for example, 24 hours) has elapsed since the ignition was turned off (step S1 and step S2).

In step S3, the automatic charging execution request signal (Extra Feeding execution request signal) is output from the electrical component controller 22.

In step S4, it is determined whether or not the bonnet (or Hood) of the hybrid vehicle is closed. If it is determined in step S4 that the bonnet is closed, the process proceeds to step S5. If it is determined in step S4 that the bonnet is not closed, the process proceeds to step S9.

In step S5, it is determined whether or not the SOC of the first battery 6 is equal to or higher than the SOC threshold value S. If it is determined in step S5 that the SOC of the first battery 6 is equal to or higher than the SOC threshold value S, the process proceeds to step S6. If it is determined in step S5 that the SOC of the first battery 6 is less than the SOC threshold value S, the process proceeds to step S9.

In step S6, the above-mentioned high-power relay-on command is output from the hybrid controller 21.

In step S7, the DC / DC converter start command, which is a start request (Extra Feeding DCDC start request) of the DC / DC converter 10 for carrying out power transmission (Extra Feeding) from the first battery 6 to the second battery 11, is hybridized. Output from the controller 21.

In step S8, power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is performed for a predetermined time (for example, 1 minute). When the power transmission (Extra Feeding) from the first battery 6 to the second battery 11 in step S8 is completed, the system is automatically put into hibernation state and the communication by the CAN communication line described above is terminated.

In step S9, power transmission (Extra Feeding) from the first battery 6 to the second battery 11 is prohibited, and the current routine is terminated.

The above-described embodiment relates to a charge control method for the hybrid vehicle 1 and a charge control device for the hybrid vehicle 1.

1 ... Hybrid vehicle 2 ... Drive wheel 3 ... Drive motor 4 ... Terminal 5 ... 1st inverter 6 ... 1st battery 7 ... 2nd inverter 8 ... Power generation motor 9 ... Internal engine 10 ... DC / DC converter 11 ... 2nd Battery 12 ... 1st deceleration mechanism 13 ... Differential gear 14 ... 2nd deceleration mechanism 15 ... Crank shaft 21 ... Hybrid controller 22 ... Electrical component controller 23 ... 1st battery controller 24 ... Engine controller

Claims (10)

A drive motor that drives the drive wheels of a hybrid vehicle,
The first battery that supplies power to the drive motor and
The electric motor for power generation that charges the first battery and
An internal combustion engine that drives the above-mentioned electric motor to generate electricity,
It has a second battery that supplies electric power to the accessories of the hybrid vehicle.
The electric motor for power generation can start the internal combustion engine by the electric power from the first battery.
In the ignition off state of the hybrid vehicle, power transmission from the first battery to the second battery is permitted within the range where the electric power required for starting the internal combustion engine can be left in the first battery, and the second battery is allowed. A charging control method for a hybrid vehicle, characterized in that the battery is charged. In the ignition off state of the hybrid vehicle, the first SOC lower limit value, which is the lower limit value of the SOC range in which the SOC of the first battery when starting the internal combustion engine can supply the electric power required to start the internal combustion engine. The charging control method for a hybrid vehicle according to claim 1, wherein power transmission from the first battery to the second battery is permitted to charge the second battery within the above range. The charge control method for a hybrid vehicle according to claim 2, wherein the first SOC lower limit value is corrected according to the temperature of the first battery. The method for controlling charging of a hybrid vehicle according to claim 2 or 3, wherein the first SOC lower limit value is corrected according to the outside air temperature. The method for controlling charging of a hybrid vehicle according to any one of claims 2 to 4, wherein the first SOC lower limit value is corrected according to the temperature of the lubricating oil of the internal combustion engine. The method for controlling charging of a hybrid vehicle according to any one of claims 2 to 5, wherein the first SOC lower limit value is corrected according to the temperature of the cooling water of the internal combustion engine. The charging control method for a hybrid vehicle according to any one of claims 2 to 6, wherein the first SOC lower limit value is corrected according to the degree of deterioration of the second battery. The SOC of the first battery is set to the first SOC after the ignition is turned off so that the SOC of the first battery does not fall below the lower limit of the first SOC even after a predetermined time T set in advance has elapsed after the ignition of the hybrid vehicle is turned off. The charging control method for a hybrid vehicle according to any one of claims 2 to 7, wherein power transmission to the second battery is repeatedly permitted until a predetermined SOC threshold value S obtained by adding a predetermined margin to the lower limit value is reached. .. In the second battery, if there is no power transmission from the first battery after the ignition of the hybrid vehicle is turned off, the SOC sets a predetermined lower limit value of the second SOC when a preset predetermined time T elapses after the ignition of the hybrid vehicle is turned off. If the value is lower than that of the hybrid vehicle and there is power transmission from the first battery after the ignition of the hybrid vehicle is turned off, the SOC is set to be equal to or higher than the second SOC lower limit value even if a preset predetermined time T has elapsed after the ignition of the hybrid vehicle is turned off. The method for controlling charging of a hybrid vehicle according to any one of claims 1 to 8, wherein the hybrid vehicle has a large capacity. A drive motor that drives the drive wheels of a hybrid vehicle,
The first battery that supplies power to the drive motor and
An electric motor for power generation, which can start the internal combustion engine by the electric power from the first battery and can be driven by the internal combustion engine to charge the first battery.
A second battery that supplies power to the accessories of the hybrid vehicle,
In the ignition off state of the hybrid vehicle, power transmission from the first battery to the second battery is permitted within the range where the electric power required for starting the internal combustion engine can be left in the first battery, and the second battery is allowed. A charge control device for a hybrid vehicle, which comprises a control unit for charging a battery.

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