JP7124352B2 - vehicle power controller - Google Patents

Description

The present invention relates to a power control device provided in a vehicle capable of automatically stopping and restarting the engine.

Conventionally, for the purpose of improving fuel consumption performance, etc., in a vehicle, a generator is driven by the engine during deceleration to generate electricity, and the so-called idling stop that automatically stops the engine during idling of the engine is implemented and the accelerator pedal is pressed. The engine is restarted in response to depression or the like.

For example, Patent Document 1 discloses a vehicle that includes a motor-generator that is connected to an engine and functions as an electric motor and a generator, and a capacitor that supplies power to the motor-generator and stores the power generated by the motor-generator. It is In this vehicle, during deceleration, the engine drives the motor generator to generate power, and the generated power is stored in the capacitor. Then, when the engine is restarted after the idle stop, the electric power of the capacitor drives the motor generator to forcibly rotate the engine.

In the vehicle of Patent Document 1, a lead-acid battery is provided in addition to the capacitor. A part of the electric power stored in the capacitor or generated by the motor generator is stepped down by the DC-DC converter and applied to the lead-acid battery and various electrical loads.

JP 2016-118126 A

In the configuration of Patent Document 1, the converter interposed between the capacitor and the electric load is configured to have only the function of stepping down the voltage without the function of stepping up the voltage. Therefore, costs can be kept low. However, in this configuration, there is a risk that an electrical load powered by a capacitor via a DC-DC converter will not operate properly.

Specifically, when the voltage of the capacitor drops significantly as the motor generator is driven when the engine is restarted, the input voltage of the converter may drop below the output voltage of the converter. When the input voltage of the converter falls below the output voltage of the converter in this way, the converter cannot step down the input voltage, and power supply from the capacitor to various electric loads via the converter stops. As a result, the power source for these electrical loads is switched to a lead-acid battery with a voltage lower than that of the capacitor, causing a sudden drop in the voltage applied to the electrical loads and possibly causing the electrical loads to not operate properly.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power control apparatus capable of appropriately restarting an engine and appropriately supplying power to an electrical load.

In order to solve the above-mentioned problems, the present invention provides a power control device provided in a vehicle capable of automatically stopping and restarting the engine, comprising: a power generation device driven by the engine to generate power; A storage battery capable of storing electric power generated by the power generation device, a driving force imparting device capable of applying driving force to an engine using the electric power of the storage battery, and an electric load provided on the vehicle and interposed between the storage battery. and a step-down device electrically connected to the electric load to supply electric power to the electric load by stepping down the voltage of the storage battery, and the step-down device electrically connected to the electric load so as to store the power output from the step-down device. A secondary storage battery having a maximum output voltage lower than that of the storage battery, and a step-down device capable of controlling the step-down device so that the output voltage of the step-down device is changed, and a request to restart the engine a control device for controlling the driving force applying device so that the driving force for restarting the engine is applied from the driving force applying device to the engine when there is an automatic When the engine is stopped, the output voltage drop control is performed to gradually decrease the output voltage of the step-down device toward an adjusted voltage that is lower than the voltage before the automatic stop of the engine and higher than the maximum output voltage of the secondary storage battery , Provided is a power control device for a vehicle, wherein the driving force applying device restarts the engine in a state where the output voltage of the step-down device is lowered below the voltage before the engine is automatically stopped (Claim 1).

According to this configuration, energy efficiency can be increased by storing energy in the storage battery as electric power during deceleration of the vehicle. Further, when the engine is restarted, the electric power stored in the storage battery is used to drive the driving force applying device to apply the driving force to the engine, so that the engine can be properly restarted. In addition, it is possible to supply electric power to the electric load by the secondary storage battery, to maintain the operation of the electric load, and to store in the secondary storage battery the electric power generated by the generator that cannot be stored in the storage battery. energy efficiency.

Moreover, in this configuration, when the engine is automatically stopped, the output voltage of the step-down device interposed between the electrical load provided in the vehicle and the storage battery is gradually reduced toward the adjusted voltage lower than the voltage before the engine was automatically stopped. Implement output voltage drop control. Therefore, the output voltage of the step-down device can be kept low when the engine is restarted after the engine is automatically stopped. Therefore, even if a large amount of electric power is supplied from the storage battery to the driving force applying device when the engine is restarted and the voltage of the storage battery drops, power supply from the storage battery to the electric load via the step-down device can be maintained. It is possible to prevent sudden changes in the voltage applied to the electrical load. In particular, in this configuration, since the output voltage of the step-down device is gradually decreased toward the regulated voltage, the output voltage of the step-down device is reduced to the regulated voltage while the output voltage of the step-down device, and thus the voltage applied to the electrical load, changes suddenly. can also be prevented. Therefore, the electric load can be operated stably and appropriately.

In the above configuration, the control device performs the output voltage reduction control when the internal resistance of the storage battery is equal to or greater than a predetermined determination resistance value, and the output voltage when the internal resistance of the storage battery is less than the determination resistance value. It is preferable to prohibit the decrease control (claim 2).

When the internal resistance of the storage battery is high, the voltage drop in the storage battery when the driving force applying device is driven using the power of the storage battery is greater than when the internal resistance of the storage battery is low, and the voltage of the storage battery tends to fall below the output voltage of the step-down device. . On the other hand, according to this configuration, even when the voltage drop of the storage battery when the engine is restarted is large due to the high internal resistance of the storage battery, power is supplied from the storage battery to the electric load via the step-down device. can be maintained, and a sudden drop in the voltage applied to the electrical load can be reliably prevented. In addition, by prohibiting output voltage drop control when the internal resistance of the storage battery is low and the voltage of the storage battery is unlikely to fall below the output voltage of the step-down device, there are many opportunities to stably supply a high voltage to the electrical load. can do.

In the above configuration, it is preferable that the control device estimates the internal resistance of the storage battery based on the deterioration state of the storage battery and the temperature of the storage battery.

By doing so, the internal resistance of the storage battery can be estimated more accurately.

In the above configuration, it is preferable that the control device sets the adjustment voltage to be lower when the internal resistance of the storage battery is high than when the internal resistance is low (claim 4).

As described above, when the internal resistance of the storage battery is high, the voltage drop of the storage battery when a device such as a driving force applying device is driven is greater than when the internal resistance is low. In contrast, in this configuration, the adjustment voltage is set to be lower when the internal resistance of the storage battery is high than when it is low. Therefore, when the engine is restarted, the output voltage of the step-down device is prevented from becoming higher than the voltage of the storage battery, and the output voltage of the step-down device is prevented from becoming excessively low. You can secure many opportunities to be supplied.

In the above configuration, the control device sets the regulated voltage to be lower when the engine is automatically stopped while the vehicle is not stopped than when the engine is automatically stopped while the vehicle is stopped. (Claim 5).

When the engine is automatically stopped while the vehicle is not stopped, the engine may be restarted while the vehicle is not stopped. When the engine is restarted in such a state that the vehicle is not stopped, the engine must be increased to a high rotational speed corresponding to the vehicle speed when the engine is restarted, and the engine is automatically stopped when the vehicle is stopped. The driving force of the driving force applying device must be increased more than ever. Therefore, in this case, the voltage drop of the storage battery increases when the engine is restarted.

In contrast, in this configuration, the adjustment voltage is lower when the engine is automatically stopped while the vehicle is not stopped than when the engine is automatically stopped while the vehicle is stopped. Therefore, even when the engine is restarted while the vehicle is not stopped, it is possible to reliably prevent the voltage of the storage battery from becoming lower than the output voltage of the step-down device when the engine is restarted. It is possible to prevent the output voltage of the step-down device from becoming excessively low when the engine is restarted, thereby securing many opportunities for stably supplying a high voltage from the storage battery to the electric load via the step-down device.

In this configuration, the vehicle includes a pair of side sills extending in the longitudinal direction of the vehicle along both sides of the compartment in the vehicle width direction, and a floor tunnel provided below the floor surface of the compartment and extending in the longitudinal direction of the vehicle. The storage battery includes a plurality of batteries arranged in a line, and the batteries are aligned in the longitudinal direction of the vehicle below the floor surface of the passenger compartment and between the floor tunnel and one of the side sills. It is preferable that they are arranged (Claim 6).

In this way, the space between the floor tunnel and the side sill can be used to mount a relatively large storage battery including a plurality of batteries on the vehicle. However, when a plurality of batteries are arranged in a row as described above, that is, when a plurality of batteries are arranged in series, the internal resistance of the storage battery increases, and the driving force applying device is disabled when the engine is restarted. The voltage drop of the storage battery during driving tends to increase. In contrast, in the present invention, as described above, even if the voltage of the storage battery drops when the engine is restarted, the output voltage of the step-down device can be maintained at a voltage lower than the voltage of the storage battery. Therefore, while laying out the storage battery as described above, the electric load can be stably operated in an appropriate state.

In the above configuration, it is preferable that, at least when the engine is restarted, the driving force imparting device is driven only by electric power of the storage battery or the secondary storage battery (claim 8).

In this way, it is possible to suppress the deterioration of the secondary storage battery by suppressing the power consumption opportunity of the secondary storage battery.

As described above, according to the power control device of the present invention, it is possible to achieve both appropriate restarting of the engine and appropriate power supply to the electric load.

1 is a diagram schematically showing the configuration of a vehicle equipped with a power control device according to an embodiment of the invention; FIG. 1 is a plan view schematically showing part of a vehicle; FIG. 1 is a schematic diagram for explaining the configuration of a DC-DC converter; FIG. 3 is a block diagram showing a control system of the engine; FIG. FIG. 10 is a diagram showing temporal changes of each parameter during vehicle travel according to a comparative example; 4 is a flowchart showing the contents of automatic engine stop control; FIG. 4 is a diagram showing the relationship between the temperature, internal resistance, and progress of deterioration of a Li battery; FIG. 4 is a diagram showing the relationship between the internal resistance of a Li battery and the target output voltage; FIG. 4 is a diagram showing a relationship between a target voltage drop and a voltage drop rate; FIG. 4 is a diagram showing temporal changes in parameters during vehicle travel;

Embodiments of the present disclosure will be described below with reference to the drawings. In addition, in each figure, the same code|symbol is attached|subjected to the same element and description is abbreviate|omitted suitably.

(1) Overall Configuration of Vehicle FIG. 1 is a diagram schematically showing the configuration of a vehicle equipped with an engine stop control device.

Vehicle 1 is, for example, a four-wheel vehicle. The engine 2 is provided in an engine room of the vehicle 1 . The driving force of the engine 2 is transmitted from the crankshaft 2a to the wheels 1a via a transmission, a final reduction gear, a drive shaft and the like, thereby causing the vehicle 1 to run.

As shown in FIG. 1, the vehicle 1 includes an engine 2 as a driving source of the vehicle, a starter 3, a motor generator 4, a Li battery (lithium battery) 9, a DC-DC converter 10, a lead battery 12, and various electric power sources. equipment is installed. The motor generator 4 is a so-called ISG (Integrated Starter-Generator) having a function as a motor and a function as a generator, as will be described later, and is hereinafter referred to as ISG4.

The Li battery 9 corresponds to the "storage battery" in the claims, the lead battery 12 corresponds to the "secondary storage battery" in the claims, and the DC-DC converter 10 corresponds to the "step-down device" in the claims. Also, the ISG 4 corresponds to a "power generation device" and a "driving force application device" in the claims. That is, in this embodiment, the power generation device and the driving force applying device are integrated into one device.

In the example of FIG. 1, the engine 2 is an in-line four-cylinder engine with four cylinders 2c arranged in a row. In this embodiment, the engine 2 is an engine driven by fuel containing gasoline. The engine 2 includes an injector 30 (see FIG. 4) that injects fuel into each cylinder 2c, and a spark plug 31 (see FIG. 4) that ignites the air-fuel mixture in each cylinder 2c. I have. One injector 30 and one spark plug 31 are provided for each cylinder 2c.

(high voltage circuit)
The Li battery 9 is electrically connected to the ISG 4, the seat heater 5 and the PTC heater 6 via a high voltage line L1, which constitute a high voltage circuit 14.

The ISG4 is a device that can operate as a generator and a motor. The ISG 4 is connected to the crankshaft 2a of the engine 2 via a belt 4a.

When operating as a generator, the ISG 4 generates power by rotating a rotor that rotates in conjunction with the crankshaft 2a of the engine 2 in a magnetic field. The ISG 4 can adjust the generated voltage within a range up to several tens of volts depending on the increase or decrease in the supply current to the field coil that generates the magnetic field. The ISG 4 incorporates a rectifier (not shown) that converts the generated AC power into DC power. The power generated by the ISG 4 is converted to direct current by this rectifier, then output to the high voltage line L1 and stored in the Li battery 9 via the high voltage line L1.

In this embodiment, the ISG 4 is controlled to operate as a generator during vehicle deceleration, converting the rotational energy of the engine 2 into electricity. That is, in this embodiment, the ISG 4 is configured to perform so-called deceleration regenerative power generation.

When operating as an electric motor, the ISG 4 is driven by power supply from the Li battery 9, transmits driving force to the crankshaft 2a of the engine 2 via the belt 4a, and imparts driving force to the engine 2. .

Thus, in this embodiment, the ISG 4 functions as a power generation device that is driven by the engine 2 to generate power, and as a driving force applying device that can apply driving force to the engine 2 using the electric power of the Li battery. Also, the Li battery functions as a storage battery capable of storing electric power generated by the ISG 4 during deceleration of the vehicle.

The ISG 4 operates as an electric motor to start the engine 2 (forcibly rotates the engine 2) when the engine is started except when cold starting. In this embodiment, the vehicle 1 is configured so that the engine 2 can be automatically stopped, and the engine 2 is restarted by the ISG 4 even when the engine 2 is restarted after the engine 2 is automatically stopped. Specifically, the engine 2 is started/stopped by an occupant's operation of an ignition switch provided in the vehicle 1 . When the vehicle speed is below a predetermined value and the engine is in an idling state, the engine 2 is automatically stopped, and when the accelerator pedal is depressed, the engine 2 is automatically restarted. be done.

Also, the ISG 4 is controlled to operate as an electric motor when the engine load is low or the like, and applies driving force to the engine 2 . That is, in this embodiment, the ISG 4 is also configured to perform so-called torque assist.

The Li battery 9 is a battery that contains lithium in its positive electrode and is charged and discharged by movement of lithium ions between the positive electrode and the negative electrode. The Li battery 9 can be charged and discharged at a faster rate than the lead battery 12 and is more resistant to deterioration due to charging and discharging than the lead battery 12 . In this embodiment, the power generated by the ISG 4 is stored in the Li battery 9, so that the deceleration energy of the engine 2 can be efficiently stored in the vehicle 1 as power. And the nominal voltage of the Li battery 9 is made higher than the negotiated voltage of the lead battery 12 so that more power generated by the ISG 4 can be stored. In this embodiment, the nominal voltage of the Li battery 9 is DC24V. Here, there is a capacitor as a device that has a high charge/discharge rate and can store a large amount of power, and the Li battery 9 can have a larger capacity than a capacitor of the same size. Therefore, in this embodiment, the miniaturization of the device for storing electric power is also realized.

FIG. 2 is a diagram for explaining the arrangement of the Li battery 9 and is a plan view schematically showing a part of the vehicle 1. As shown in FIG. In the example of FIG. 2, the engine room 1 is formed in the front part of the vehicle 1, and the passenger compartment 80 is formed behind it.

The vehicle 1 includes a panel 81 that is provided above a floor panel and constitutes the floor surface of the vehicle compartment, and a vehicle compartment that is provided below openings (door portions) formed on both sides in the vehicle width direction of the vehicle. A pair of side sills 82 extending in the vehicle front-rear direction are provided along both side portions of 80 in the vehicle width direction. The vehicle 1 also includes a floor tunnel 83 provided below the panel 81 so as to communicate with the engine room 1 and through which a duct for discharging exhaust gas from the engine 2 to the outside of the vehicle 1 passes. The floor tunnel 83 is formed by expanding the center portion of the floor panel 81 in the vehicle width direction upward. The Li battery 9 is arranged below the panel 81 and between the floor tunnel 83 and one side sill 82 (the right side sill 82 in the example of FIG. 2). In the example of FIG. 2, the Li battery 9 is arranged below the front part of the panel 81 and below the driver's seat or passenger's seat.

By arranging in this way, in this embodiment, the distance between the ISG 4 and the Li battery 9 as well as the electric wire connecting them is kept short.

Here, the distance between the floor tunnel 83 and the side sill 82 in the vehicle width direction is short. On the other hand, in the present embodiment, a plurality of Li storage battery cells (batteries) 9a constituting the Li battery 9 are arranged in a row and connected in series so that the Li battery 9 is a predetermined It has a shape that extends long in the direction of . The Li battery 9 is arranged such that its longitudinal direction, that is, the arrangement direction of the cells 9a, is along the vehicle front-rear direction. As a result, the Li battery 9 can be arranged at a position where the distance to the ISG 4 can be kept short as described above.

A seat heater 5 (an example of a high-voltage electric device, an example of a vehicle interior heater) is a heater for heating the seat of the vehicle 1 . A PTC heater 6 (an example of a high-voltage electric device, an example of a vehicle interior heater) is a heater for heating the interior of the vehicle 1 . The catalyst heater 7 is a heater for heating a catalyst that purifies exhaust gas. The seat heater 5, the PTC heater 6, and the catalyst heater 7 are arranged on the side of the high voltage line L1 because they operate stably even at several tens of VDC.

(low voltage circuit)
The lead battery 12 is electrically connected to the starter 3 and the low voltage electrical equipment 13 via the low voltage line L2, which form a low voltage circuit 15. This low-voltage electrical device 13 corresponds to the "electrical load" in the claims.

The lead-acid battery 12 includes a series-connected 6-cell lead-acid battery in this embodiment. With this configuration, the nominal voltage of the lead battery 12 is DC12V.

Starter 3 is a device for starting engine 2 . The starter 3 is a gear-driven device and has a pinion gear 3a connected to the ring gear 2b of the engine 2. As shown in FIG. The driving force of the starter 3 is transmitted to the crankshaft 2a of the engine 2 via the pinion gear 3a and the ring gear 2b. The starter 3 is driven to start the engine 2 only during a cold start (when the engine 2 is started in response to an ignition switch being operated by an occupant in a cold state).

The low-voltage electrical equipment 13 is an electrical equipment that operates at a voltage equal to or lower than the nominal voltage of the lead battery 12 (DC 12 V in this embodiment). The low-voltage electrical equipment 13 includes, for example, an electric power steering mechanism (EAPS), an air conditioner, audio equipment, and various lighting devices.

(DC-DC converter)
A DC-DC converter 10 is provided between a high voltage circuit 14 and a low voltage circuit 15 and connects these circuits 14 and 15 together.

The DC-DC converter 10 is a device for stepping down the voltage of power supplied from the high voltage line L1 to the low voltage line L2 (that is, from left to right in FIG. 1). The power output from the Li battery 9 and the power generated by the ISG 4 are stepped down in voltage by the DC-DC converter 10 and supplied to the low-voltage electrical equipment 13 . Moreover, the surplus part of the electric power generated by ISG4 is supplied to the lead battery 12, and the lead battery 12 is charged.

The DC-DC converter 10 does not have other functions, such as the function of allowing power supply in the opposite direction (that is, from the right side to the left side in FIG. 1) or boosting the voltage. Instead, it only steps down the voltage. With such a configuration, in the present embodiment, while connecting the high voltage line L1 and the low voltage line L2, the structure of the converter for connecting them can be simplified, and the cost can be reduced remarkably.

FIG. 3 is a schematic diagram for explaining the configuration of the DC-DC converter 10. As shown in FIG. The DC-DC converter 10 incorporates switching elements 10a and 10b (Hi-FET 10a and Low-FET 10b) made up of FETs, and changes and outputs an input voltage by on/off switching of these switching elements 10a and 10b. In this DC-DC converter 10, the output voltage can be changed by changing the ON/OFF times of the switching elements 10a and 10b. The on/off times of the switching elements 10a and 10b are changed by an ECU 100, which will be described later. The ECU 100 sets a target value of the output voltage, as will be described later. The on/off times of 10a and 10b are calculated, and a command signal is output to the DC-DC converter 10 so as to realize the on/off times.

Here, the output voltage of the DC-DC converter 10 is basically , a basic output voltage well above the nominal voltage of the lead-acid battery 12 and the operating voltage of the low-voltage electrical appliance 13 . That is, the target output voltage, which is the target value of the output voltage of the DC-DC converter 10, is set as the basic output voltage. , 10b) are controlled. In this embodiment, the nominal voltage of the lead battery 12 is 12V, while the basic output voltage is set to 14.4V. Note that this basic output voltage may be changed according to the liquid temperature of the Li battery 9 or the like.

(2) Control System FIG. 3 is a block diagram schematically showing the electrical configuration of the control system of vehicle 1 shown in FIG. The ECU 100 shown in FIG. 3 is a microprocessor for overall control of the engine, and is composed of a well-known CPU, ROM, RAM, and the like.

Information detected by various sensors and operation signals of various switches are input to the ECU 100 .

Specifically, the vehicle 1 includes a crank angle sensor SN20, a water temperature sensor SN21, an outside air temperature sensor SN22, an accelerator sensor SN23, a brake sensor SN24, a vehicle speed sensor SN25, a Li battery voltage sensor SN26, a Li battery current sensor SN27, and an ignition switch SW28. , a PTC heater switch SW29, a seat heater switch SW30, and the like are provided.

The crank angle sensor SN20 detects the rotation speed of the crankshaft 2a and the engine speed. A water temperature sensor SN21 detects the temperature of engine cooling water for cooling the engine 2 . The outside air temperature sensor SN22 detects the outside air temperature, that is, the air temperature around the vehicle 1 . The accelerator sensor SN23 detects the amount of depression of an accelerator pedal provided in the vehicle 1 . A brake sensor SN24 detects the amount of depression of the foot brake pedal. A vehicle speed sensor SN25 detects the vehicle speed. Li battery voltage sensor SN26 and Li battery current sensor SN27 detect input/output voltage and input/output current of Li battery 9, respectively. The ignition SW (ignition switch) 20 is a switch for the passenger to start/stop the engine 2 as described above. The PTC heater SW28 is a switch for driving/stopping the PTC heater 6 by the passenger. The seat heater SW29 is a switch for driving/stopping the seat heater 5 by the passenger.

The ECU 100 controls each device provided in the vehicle 1 while executing various determinations and calculations based on input information from each sensor and each switch. The ECU 100 is electrically connected to the injector 30, the spark plug 31, the starter 3, the ISG 4, the seat heater 5, the PTC heater 6, the DC-DC converter 10, the low voltage electrical equipment 13, etc. Based on this, control signals are output to each of these devices. The ECU 100 corresponds to a "control device" in the claims.

For example, if the ignition switch 20 is operated when the temperature of the engine cooling water detected by the water temperature sensor SN21 is lower than a predetermined temperature, the ECU 100 determines that the cold start is being performed and drives the starter 3 . The ECU 100 drives the seat heater 5, the PTC heater 6, the low-voltage electric device 13, etc. according to the operation of the switches such as the PTC heater SW28, the seat heater SW29, and the like.

Further, the ECU 100 drives the ISG 4 as a generator when the vehicle speed detected by the vehicle speed sensor SN25 is decreasing, and causes the ISG 4 to perform deceleration regenerative power generation as described above. The ECU 100 calculates the engine load based on the amount of depression of the accelerator pedal and the engine speed detected by the crank angle sensor SN20. 2 is torqued.

Further, the ECU 100 automatically stops the engine 2 when a predetermined condition is satisfied. Further, after that, when the conditions such as the brake pedal not being depressed and the accelerator pedal being depressed are met, the ISG 4 is driven as an electric motor to restart the engine 2 .

Here, if the DC-DC converter 10 having a step-down function is used as the converter that connects the high voltage circuit 14 and the low voltage circuit 15 as described above, the cost can be kept extremely low. However, with this configuration, the voltage applied to the low-voltage electrical device 13 connected to the low-voltage circuit 15 may drop suddenly when the engine 2 is restarted.

A specific description will be given with reference to FIG. FIG. 5 is a diagram schematically showing temporal changes in each parameter of the vehicle when the output voltage drop control described later is not performed. FIG. 5 shows vehicle speed, engine speed, voltage of the Li battery 9, output voltage of the DC-DC converter 10, and voltage input to the low voltage electric device 13 in order from the top.

When the vehicle starts decelerating at time t11, the ISG 4 is driven as a generator to generate power, and the voltage of the Li battery 9 rises. However, when the engine 2 is automatically stopped at time t12 as the engine speed drops to the idling speed, the voltage of the Li battery 9 gradually drops. After that, at time t13, when there is a request to restart the engine, the ISG 4 is driven as an electric motor and the engine 2 is forcibly rotated. At this time, a very large amount of electric power is discharged from the Li battery 9 toward the ISG 4, and the voltage of the Li battery 9 rapidly drops. If this voltage drop amount is large, the voltage of the Li battery 9 will drop below the output voltage of the DC-DC converter 10 indicated by the broken line. Then, when the voltage of the Li battery 9 drops below the output voltage of the DC-DC converter 10, power is supplied from the Li battery 9 to the low voltage circuit 15 side because the DC-DC converter 10 only has a step-down function. and the voltage input to the low voltage electrical load 13 drops sharply.

In this embodiment, since the lead battery 12 is provided in the low voltage circuit 15, even if the power is not output from the DC-DC converter 10, each low voltage provided in the low voltage circuit 15 by the lead battery 12 Power supply to the electrical equipment 13 can be maintained. However, as described above, the output voltage of the DC-DC converter 10 is basically set to a value sufficiently higher than the nominal voltage of the lead battery 12 . Therefore, when power is no longer output from the DC-DC converter 10 and the power supply source for each low-voltage electrical device 13 is switched to the lead battery 12, the voltage supplied to these low-voltage electrical devices 13 drops sharply. The operating state of the low-voltage electrical equipment 13 changes. For example, when the light is operating as a low voltage electrical appliance 13, the light may flicker. Also, when the audio is operating as the low-voltage electrical device 13, the volume of the audio may change. These make the passenger feel uncomfortable.

Therefore, in the present embodiment, output voltage drop control is performed to prevent the voltage supplied to the low-voltage electrical device 13 from suddenly dropping when the engine is automatically stopped.

(automatic stop control)
The control when the engine 2 is automatically stopped, including the output voltage drop control, will be described with reference to the flowchart of FIG. 6 and the like. In the following description and FIG. 6, automatic stop of the engine is referred to as idle stop.

In step S1, the ECU 100 reads various types of vehicle information including detection values of the sensors. After step S1, the process proceeds to step S2.

In step S2, the ECU 100 determines whether or not an idle stop permission condition, which is a condition indicating that the vehicle 1 is ready to perform an idle stop, is satisfied. In this embodiment, the temperature of the engine cooling water is equal to or higher than a predetermined temperature, the engine speed is equal to or lower than a predetermined speed, the accelerator pedal is in an off state (accelerator opening is zero), and the foot brake pedal is depressed. When the amount is greater than 0 (the foot brake pedal is depressed), it is determined that the idling stop permission condition is satisfied.

When the determination in step S2 is NO and the idling stop permission condition is not satisfied, the ECU 100 directly ends the process (returns to step S1).

On the other hand, when the determination in step S2 is YES and the idle stop permission condition is satisfied, the process proceeds to step S3. In step S3, the ECU 100 determines that the vehicle speed is equal to or lower than a preset first determination vehicle speed and greater than a preset second determination vehicle speed, and furthermore, the SOC (State Of Charge) of the Li battery 9 is preset. It is determined whether or not a specific condition of being equal to or higher than the determined SOC is established. The first determination vehicle speed is a value greater than 0 km/h, and is set to approximately 16 km/h, for example. The second determination vehicle speed is a value smaller than the first determination vehicle speed and is set to 0 km/h. The determination SOC is set to a value greater than 0 and less than 100%.

When the determination in step S3 is YES and the specific condition is satisfied, that is, the vehicle speed is higher than the second determination vehicle speed and the vehicle is not completely stopped, but the vehicle speed is lower than the first determination vehicle speed. And when the SOC of the Li battery 9 is equal to or higher than the judgment SOC and relatively large amount is ensured, the process proceeds to step S4. In step S4, the ECU 100 sets the vehicle speed flag to 1. This vehicle speed flag is set to 1 when the determination in step S3 is YES, and set to 0 otherwise. Although not shown, the vehicle speed flag is reset to 0 when the determination in step S2 is NO. After step S4, the process proceeds to step S7.

On the other hand, when the determination in step S3 is NO and the specific condition is not established, the process proceeds to step S5. In step S5, the ECU 100 determines whether the vehicle speed is equal to or lower than the second determination vehicle speed and the vehicle is stopped.

If the determination in step S5 is YES and the vehicle speed is equal to or lower than the second determination vehicle speed (when the vehicle is stopped), the process proceeds to step S6. In step S6, the ECU 100 sets the vehicle speed flag to 0. After step S6, the process proceeds to step S7.

In step S7, the ECU 100 determines whether or not the internal resistance of the Li battery 9 is equal to or greater than a preset determination resistance value.

The internal resistance of the Li battery 9 is estimated from the temperature of the Li battery 9 and the progress of deterioration of the Li battery 9 .

Specifically, the ECU 100 determines the amount of heat generated by the charging and discharging of the Li battery 9 based on the input/output voltage and input/output current of the Li battery 9 detected by the Li battery voltage sensor SN26 and the Li battery current sensor SN27. The temperature is estimated as needed, and the amount of temperature rise of the Li battery 9 due to this heat generation is estimated as needed based on the estimated amount of heat generation. Furthermore, the ECU 100 estimates the temperature of the Li battery 9 at any time based on this amount of temperature rise and the outside air temperature.

In addition, the ECU 100 detects the current and voltage (the current and voltage detected by the Li battery voltage sensor SN26 and the Li battery current sensor SN27) released from the Li battery 9 when the ISG 4 is driven along with the engine restart. , the progress of deterioration of the Li battery 9 is estimated. Specifically, the ECU 100 estimates that the Li battery 9 is more deteriorated as the current discharged from the Li battery 9 decreases and as the voltage discharged from the Li battery 9 decreases. In the present embodiment, a parameter that has a larger value as the current is lower and the voltage is lower, and is a parameter that quantifies the progress of deterioration of the Li battery 9 (hereinafter referred to as a deterioration parameter as appropriate) is set. , the ECU 100 calculates the value of the deterioration parameter based on the current and voltage. The ECU 100 calculates, updates, and stores the value of the deterioration parameter each time the ISG 4 is driven as the engine is restarted.

In this embodiment, the ECU 100 stores a map shown in FIG. In this map, the temperature of the Li battery 9 is plotted on the horizontal axis, and the internal resistance of the Li battery 9 is plotted on the vertical axis. Also, the plurality of lines shown in this map are lines having different values of deterioration parameters (progress of deterioration of the Li battery 9). From this map, the ECU 100 determines the temperature of the Li battery 9 corresponding to the estimated value of the temperature of the Li battery 9 at the present time (when step S7 is performed) and the deterioration parameter value stored at the present time (when step S7 is performed). The internal resistance is extracted and estimated as the internal resistance of the Li battery 9 at the present time (when step S7 is performed). As shown in FIG. 7, the lower the temperature of the Li battery 9, the higher the value of the deterioration parameter, and the greater the degree of deterioration of the Li battery 9, the higher the internal resistance of the Li battery 9 is estimated.

Returning to FIG. 6, when the determination in step S7 is NO and the internal resistance of the Li battery 9 is less than the determination resistance value, the ECU 100 proceeds to step S8. In step S8, the ECU 100 maintains the target output voltage, which is the target value of the output voltage of the DC-DC converter 10, at the basic output voltage, and proceeds to step S13. Hereinafter, the target output voltage, which is the target value of the output voltage of the DC-DC converter 10, will simply be referred to as the target output voltage.

In step S13, the ECU 100 performs idle stop. Specifically, the ECU 100 stops fuel injection by the injector 30 and stops ignition by the spark plug 31 . As described above, when the internal resistance of the Li battery 9 is less than the determination resistance value, the idle stop is performed without performing the output voltage drop control described later.

On the other hand, when the determination in step S7 is YES and the internal resistance of the Li battery 9 is equal to or greater than the determination resistance value, the ECU 100 proceeds to step S8.

In step S8, the ECU 100 determines the target output voltage based on the estimated internal resistance of the Li battery 9 and the vehicle speed flag.

FIG. 8 is a graph showing the relationship between the internal resistance of the Li battery 9 and the target output voltage. In FIG. 8, the solid line is the line when the vehicle speed flag is 0, and the dashed line is the line when the vehicle speed flag is 1. As described above, when the determination in step S7 is NO and the internal resistance of the Li battery 9 is less than the determination resistance value, the output voltage of the DC-DC converter 10 is maintained at the basic output voltage. On the other hand, when the internal resistance of the Li battery 9 is equal to or higher than the determination resistance value, the target output voltage is lower than the basic output voltage regardless of whether the vehicle speed flag is 1 or 0. Further, when the internal resistance of the Li battery 9 is equal to or higher than the determination resistance value, the target output voltage is set to a smaller value when the internal resistance of the Li battery 9 is large than when it is small. In the example of FIG. 8, the target output voltage is reduced in proportion to the internal resistance of the Li battery 9 as the internal resistance increases. As shown in FIG. 8, the target output voltage is smaller when the vehicle speed flag is 1 than when the vehicle speed flag is 0 even if the internal resistance of the Li battery 9 is the same. The voltage which is the target output voltage set in step S9 and which is lower than the basic output voltage is the "adjustment voltage" referred to in the claims.

For example, in the example of FIG. 8, the determination resistance value is 13 mΩ. Also, the basic output voltage is set to 14.4V. When the vehicle speed flag is 1, the target output voltage is about 13.8 V when the Li battery internal resistance increases to 13.5 mΩ. On the other hand, when the vehicle speed flag is 0, the target output voltage is about 14.2 V when the Li battery internal resistance increases to 13.5 mΩ.

After step S9, the process proceeds to step S10. In step S10, the ECU 100 controls the DC-DC converter 10 based on the difference between the current output voltage (current output voltage) of the DC- DC converter 10 (when step S10 is executed) and the target output voltage determined in step S9. determines the voltage drop rate, which is the rate of drop of the output voltage of the In the present embodiment, a command value for the output voltage set by the ECU 100 is used as the current output voltage.

FIG. 9 is a diagram showing the relationship between the target value of the amount of decrease in the output voltage (hereinafter referred to as target voltage drop), which is a value obtained by subtracting the target output voltage from the actual output voltage, and the voltage drop rate. As shown in FIG. 9, in this embodiment, when the target voltage drop is large, the voltage drop rate is set higher than when the target voltage drop is small. In the example of FIG. 9, when the target voltage drop is equal to or higher than the predetermined value dV0, the voltage drop speed is kept constant, and when the target voltage drop is less than the predetermined value dV0, the voltage drop speed increases in proportion to the target voltage drop as the target voltage drop increases. made smaller. For example, the target voltage drop is set to approximately 0.5 V/sec to 2 V/ses.

After step S10, the process proceeds to step S11. In step S11, the ECU 100 reduces the output voltage of the DC-DC converter 10. FIG. Specifically, the ECU 100 changes the ON/OFF times of the switching elements 10a and 10b built in the DC-DC converter 10, as described above. At this time, the ECU 100 adjusts the ON/OFF times of the switching elements 10a and 10b so that the output voltage of the DC-DC converter 10 decreases at the voltage decrease rate set in step S10. As a result, the output voltage of the DC-DC converter 10 is gradually decreased toward the target output voltage.

After step S11, the process proceeds to step S12. In step S12, it is determined whether or not the current output voltage of the DC-DC converter 10 has become equal to or less than the target output voltage. If the determination is NO and the current output voltage of the DC-DC converter 10 has not yet decreased to the target output voltage, the process returns to step S11. On the other hand, when the determination is YES and the current output voltage of the DC-DC converter 10 drops to the target output voltage, the process proceeds to step S13 and an idle stop is performed.

As described above, in the present embodiment, when the internal resistance of the Li battery 9 is less than the determination resistance value, the ECU 100 does not immediately perform the idle stop even if the idle stop permission condition is satisfied, and the DC-DC Output voltage reduction control is performed to reduce the output voltage of converter 10 from the basic target voltage toward a voltage lower than the basic target voltage and to gradually reduce the output voltage. Also, at this time, the idle stop is performed only after the output voltage of the DC-DC converter 10 has decreased to the target output voltage.

In this embodiment, when the idle stop is performed after the output voltage has decreased to the target output voltage, the output voltage of the DC-DC converter 10 is reduced at least until the engine is restarted. Maintain target output voltage.

(3) Effects, etc. FIG. 10 is a diagram schematically showing changes over time in each parameter when automatic engine stop control including the output voltage reduction control is performed while the vehicle is running. FIG. 10 shows, from top to bottom, vehicle speed, idle stop permission flag, engine speed, temperature of Li battery 9, internal resistance of Li battery 9, voltage of Li battery 9, output voltage of DC-DC converter 10, low voltage. The voltage input to the electrical equipment 13 is shown. The idle stop permission flag becomes 1 when the idle stop permission condition is satisfied, and becomes 0 otherwise.

As shown in FIG. 10, the temperature of the Li battery 9 gradually increases as the vehicle travels, and accordingly the internal resistance of the Li battery 9 gradually decreases.

When the vehicle starts decelerating at time t1, the ISG 4 starts generating power. Accordingly, the voltage of Li battery 9 gradually increases after time t1.

At time t2, the idle stop permission condition is met (the idle stop permission flag changes from 0 to 1). However, the internal resistance of the Li battery 9 at time t2 is greater than or equal to the determination resistance value. Therefore, at time t2, the idle stop is not performed and the output voltage drop control is started. As described above, in this embodiment, the target output voltage decreases at a predetermined rate of decrease, and the output voltage of the DC-DC converter 10 gradually decreases after time t2. Along with this, the input voltage of the low-voltage electric load 13 also gradually decreases after time t2. At time t3, when the output voltage of DC-DC converter 10 drops to voltage V1, which is lower than basic output voltage V0, which is target output voltage V1, engine 2 is stopped by idling stop. After time t3, the output voltage of the DC-DC converter 10 is maintained at the target output voltage V1.

After time t2, the power supply from the ISG 4 to the Li battery 9 stops as the engine 2 is idled and stopped. Therefore, after time t2, the voltage of Li battery 9 gradually decreases.

At time t4, when the condition for permitting idle stop is not satisfied and the condition for restarting the engine is satisfied, the ISG 4 is driven as an electric motor. As a result, the voltage of the Li battery 9 drops sharply. However, at this time, the output voltage of the DC-DC converter 10 is the low voltage V1. Therefore, the voltage of Li battery 9 is maintained at a value higher than the output voltage of DC-DC converter 10 . Therefore, at time t4, the input voltage of the low - voltage electric load 13 does not suddenly drop, and the low-voltage electric load 13 is stably supplied with the required voltage.

As the engine is restarted at time t4, the output voltage of the DC - DC converter 10 is returned to the basic output voltage V0. In the example of FIG. 9, the output voltage of the DC-DC converter 10 is then gradually increased toward the basic output voltage V0.

Thereafter, after the vehicle has been accelerated and has been running steadily, at time t5, when the vehicle starts decelerating again, the voltage of Li battery 9 increases in the same manner as described above. At time t6, the idle stop permission condition is established. At this time as well, the internal resistance of the Li battery 9 is still equal to or higher than the determination resistance value, so the output voltage of the DC-DC converter 10 is the basic output voltage V0. is gradually decreased to a voltage V2 that is lower than the voltage V2, and then an idle stop is performed at time t7.

Here, at time t6, the vehicle speed is greater than 0, that is, the vehicle speed flag is 1, and the condition for permitting idle stop is satisfied. On the other hand, at time t2, the vehicle speed is 0 and the vehicle speed flag is 0, and the idle stop permission condition is satisfied. Therefore, the target output voltage V2 of DC-DC converter 10 set at time t6 (the output voltage realized at time t7) is the target output voltage V2 of DC-DC converter 10 set at time t2 (time t3 is lower than V1.

Also, in the same manner as described above, the voltage of the Li battery 9 gradually drops after time t6, and drops sharply when the engine is restarted at time t8. However, even at this time, the voltage of the Li battery 9 is maintained higher than the output voltage V2 of the DC-DC converter 10, and a sudden change in the input voltage of the low voltage electric load 13 is prevented.

On the other hand, when the idle stop permission flag becomes 1 at time t10 after the internal resistance of the Li battery 9 has fallen below the judgment resistance value at time t9, the internal resistance of the Li battery 9 is less than the judgment resistance value. , the output voltage reduction control is not performed, and the engine 2 is stopped immediately at time t10 by performing an idle stop.

As described above, according to the device according to the present embodiment, the energy efficiency of the vehicle as a whole can be increased by storing energy in the Li battery 9 as electric power when the vehicle decelerates. Further, when the engine 2 is restarted, the electric power stored in the Li battery 9 can be used to drive the ISG 4 to apply driving force to the engine 2, and the engine 2 can be appropriately restarted.

Moreover, when the engine is automatically stopped, the output voltage drop control is performed to gradually decrease the output voltage of the DC-DC converter 10 toward a voltage lower than the voltage before the automatic stop of the engine 2, and the output of the DC-DC converter 10 The engine is restarted while the voltage is maintained at the low voltage. Therefore, during the period from the automatic stop of the engine to the restart of the engine, the output voltage of the DC-DC converter 10 can be maintained at a voltage lower than the voltage of the Li battery 9, and from the Li battery 9 to the DC-DC converter 10 can continue to power the low voltage electrical load 13 via the . Therefore, when the engine is restarted, it is possible to prevent the ISG 4 from being driven as an electric motor and the power supply being stopped and the operating state of the low-voltage electric load 13 suddenly changing. Particularly, in this embodiment, the output voltage of the DC-DC converter 10 is gradually decreased when the engine is automatically stopped. Therefore, it is possible to reduce the output voltage of the DC-DC converter 10 to obtain the above effect, and to prevent the voltage applied to the low-voltage electric load 13 from suddenly changing due to the reduction in the output voltage. 13 can be stably and appropriately operated.

Further, in the present embodiment, the output voltage drop control is performed only when the internal resistance of the Li battery 9 is equal to or higher than the determination resistance value, and the output voltage drop control is performed when the internal resistance of the Li battery 9 is less than the determination resistance value. Do not implement (prohibit). Therefore, when the voltage drop of the Li battery 9 is large due to the high internal resistance of the Li battery 9 and the input voltage of the low voltage electric load 13 tends to drop suddenly, the sudden drop of the input voltage of the low voltage electric load 13 is ensured. can be prevented. Further, it is possible to prevent the output voltage of the DC-DC converter 10 from being lowered excessively when the input voltage of the low-voltage electric load 13, which is relatively pulled by the internal resistance of the Li battery 9, is unlikely to suddenly drop. Therefore, it is possible to secure many opportunities for stably supplying a high voltage from the Li battery 9 to the low voltage electric load 13 via the DC-DC converter 10 .

Further, in the present embodiment, as described with reference to FIG. 7, when the output voltage drop control is performed, the engine is automatically stopped when the vehicle speed flag is 1 and the vehicle is not stopped. In this case, the output voltage of the DC-DC converter 10 is made lower than when the engine is automatically stopped while the vehicle speed flag is 0 and the vehicle is stopped.

Therefore, when the engine is restarted, the voltage of the Li battery 9 is prevented from becoming lower than the output voltage of the DC-DC converter, and the output voltage of the DC-DC converter 10 is prevented from being excessively lowered. A large number of opportunities for stably supplying a high voltage to the electric load 13 can be ensured.

Specifically, when the engine is automatically stopped while the vehicle is not stopped, the engine may be restarted while the vehicle is not stopped. When the engine is restarted in such a state that the vehicle is not stopped, the engine must be increased to a high rotational speed corresponding to the vehicle speed when the engine is restarted, and the engine is automatically stopped while the vehicle is stopped. The driving force of ISG4 must be made higher than the time. In addition, the driving force of the ISG 4 must be increased because electric power must be supplied to the braking device. Therefore, when the engine is restarted while the vehicle is not stopped, the amount of voltage drop in the Li battery 9 increases when the engine is restarted.

On the other hand, with the configuration as described above, according to the present embodiment, even when the engine is automatically stopped while the vehicle is not stopped and the engine is restarted while the vehicle is not stopped. , the voltage of the Li battery can be reliably prevented from becoming lower than the output voltage of the DC-DC converter. The output voltage of the DC-DC converter 10 is excessively lowered when the engine is automatically stopped while the vehicle is stopped and the amount of voltage drop in the Li battery 9 is suppressed when the engine is restarted. can be prevented.

Further, according to the present embodiment, the Li battery 9 in which a plurality of Li storage battery cells are arranged in a row is used, and this is placed below the floor panel 81 and between the floor tunnel 83 and the side sill 82. are placed in the space of Therefore, by utilizing this space, the Li battery 9 can be appropriately arranged at a position closer to the ISG 4 . It is possible to shorten the distance between the ISG 4 and the Li battery 9, as well as the electric wire connecting them.

However, when a plurality of batteries are arranged in a row and connected in series in this manner, the internal resistance of the Li battery 9 tends to increase. If the internal resistance of the Li battery 9 is large, the voltage of the Li battery 9 tends to drop significantly when the engine is restarted. In contrast, in the present embodiment, as described above, even if the voltage of the Li battery 9 drops when the engine is restarted, the output voltage of the DC-DC converter 10 is maintained at a voltage lower than the voltage of the Li battery 9. be done. Therefore, while realizing the layout described above, the power supply from the Li battery 9 to the low-voltage electric device 13 can be maintained and the operation thereof can be stabilized.

(4) Modification In the above-described embodiment, when the engine 2 is automatically stopped, the output voltage drop control is performed when the internal resistance of the Li battery 9 is equal to or higher than the determination resistance value, and the internal resistance of the Li battery 9 is the determination resistance value. Although the case where the output voltage drop control is not performed when the value is less than the above, the output voltage drop control may be always performed regardless of the internal resistance of the Li battery 9 .

Further, a parameter other than the internal resistance of the Li battery 9 may be used to determine whether the output voltage reduction control is to be executed or prohibited. For example, when the deterioration of the Li battery 9 has progressed beyond a predetermined state, the output voltage drop control is performed, and when the deterioration of the Li battery 9 has not progressed to the predetermined state, the output voltage drop control is prohibited. may Alternatively, the output voltage reduction control may be performed when the temperature of the Li battery 9 is less than a predetermined temperature, and may be prohibited when the temperature of the Li battery 9 is equal to or higher than the predetermined temperature.

Further, the determination of whether to perform or prohibit the output voltage drop control may be made based on the SOC of the Li battery 9 . For example, the output voltage drop control may be performed when the SOC of the Li battery 9 is less than a predetermined value, and the output voltage drop control may be prohibited when the SOC of the Li battery 9 is greater than or equal to the predetermined value. Furthermore, by combining the SOC of the Li battery 9 and the internal resistance of the Li battery 9, when the SOC of the Li battery 9 is less than a predetermined value and the internal resistance of the Li battery 9 is greater than or equal to a predetermined value, output voltage drop control is performed. , when the SOC of the Li battery 9 is equal to or higher than a predetermined value, or when the internal resistance of the Li battery 9 is less than a predetermined value, the output voltage reduction control may be prohibited.

Moreover, although the said embodiment demonstrated the case where the Li battery 9 was used as a storage battery which stores the electric power generated by ISG4, this storage battery is not restricted to the Li battery 9. FIG.

2 engine 4 ISG (power generator, driving force applying device)
9 Li battery (storage battery)
10 DC-DC converter (step-down device)
12 lead battery (secondary storage battery)
13 Low-voltage electrical equipment (electrical load)
14 high voltage circuit 15 low voltage circuit 100 ECU (control device)

Claims (7)

A power control device provided in a vehicle capable of automatically stopping and restarting the engine,
a power generating device driven by an engine to generate power;
a storage battery capable of storing electric power generated by the power generation device when the vehicle decelerates;
a driving force imparting device capable of imparting a driving force to an engine using electric power of the storage battery;
a voltage step-down device interposed between an electric load provided in a vehicle and the storage battery for stepping down the voltage of the storage battery and supplying electric power to the electric load;
a secondary storage battery electrically connected to the electric load and electrically connected to the step-down device so as to store power output from the step-down device, and having a maximum output voltage lower than that of the storage battery;
The step-down device can be controlled so that the output voltage of the step-down device is changed, and when there is a request to restart the engine, the driving force for restarting the engine is supplied from the driving force applying device to the engine. A control device that controls the driving force applying device so that the driving force applying device is applied to
When the engine is automatically stopped, the control device reduces the output voltage of the step-down device to a level lower than the voltage before the engine was automatically stopped.and higher than the maximum output voltage of the secondary storage batteryIn a state in which the output voltage drop control is performed to gradually decrease the output voltage to the lower adjustment voltage, and the output voltage of the step-down device is decreased below the voltage before the engine automatically stopped.By the driving force applying deviceAn electric power control device for a vehicle, characterized by restarting an engine. In the vehicle power control device according to claim 1,
The control device performs the output voltage drop control when the internal resistance of the storage battery is equal to or greater than a predetermined determination resistance value, and prohibits the output voltage drop control when the internal resistance of the storage battery is less than the determination resistance value. A power control device for a vehicle, characterized by: In the vehicle power control device according to claim 2,
A power control device for a vehicle, wherein the control device estimates an internal resistance of the storage battery based on a deterioration state of the storage battery and a temperature of the storage battery. In the vehicle power control device according to any one of claims 1 to 3,
A power control device for a vehicle, wherein the control device sets the regulated voltage to be lower when the internal resistance of the storage battery is high than when the internal resistance is low. In the vehicle power control device according to any one of claims 1 to 4,
The control device sets the regulated voltage to be a lower voltage when the engine is automatically stopped while the vehicle is not stopped than when the engine is automatically stopped while the vehicle is stopped. A power control device for a vehicle characterized by: In the vehicle power control device according to any one of claims 1 to 5,
The vehicle includes a pair of side sills extending in the vehicle front-rear direction along both sides of the vehicle interior in the vehicle width direction, and a floor tunnel provided below the floor surface of the vehicle interior and extending in the vehicle front-rear direction,
The storage battery includes a plurality of batteries arranged in a line, and the batteries are arranged below the floor surface of the passenger compartment and between the floor tunnel and one of the side sills in the longitudinal direction of the vehicle. A power control device for a vehicle, characterized in that: In the vehicle power control device according to claim 6 ,
An electric power control apparatus for a vehicle, wherein the driving force imparting device is driven by only the electric power of the storage battery or the secondary storage battery at least when the engine is restarted.

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