JP7064393B2 - Control device - Google Patents

Description

The present invention relates to a control device applied to an in-vehicle power supply system having a storage battery.

In a vehicle equipped with an engine as an internal combustion engine, there is a vehicle that warms up when the engine is cold-driven (for example, Patent Document 1). In the vehicle of Patent Document 1, power generation by an alternator and power generation by a rotary electric machine are both performed during cold driving. As a result, the engine load due to power generation can be increased and warm-up can be performed promptly.

Japanese Unexamined Patent Publication No. 2017-217930

In the above vehicle, it is desired to increase the engine load during warm-up to complete warm-up at an early stage.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device capable of promptly completing warm-up.

In order to solve the above problems, an internal combustion engine, a generator that generates electricity by using the output torque of the internal combustion engine, a first storage battery, a second storage battery having a higher internal resistance than the first storage battery, and the power generation. The internal combustion engine is being driven in a control device applied to an in-vehicle power supply system including a switch provided in an electric path in which the first storage battery and the second storage battery are connected in parallel to the machine. During cold driving in which the temperature of the internal combustion engine is equal to or lower than a predetermined temperature, a generator control unit that controls the generator so as to use the output torque of the internal combustion engine to generate electricity, and cooling of the internal combustion engine. It is provided with a power supply control unit that controls the switch so as to energize at least between the generator and the first storage battery during the inter-drive.

When the first storage battery is charged by energizing the battery with the first storage battery having a low internal resistance, the generated current from the generator is larger than that when only the second storage battery having a high internal resistance is charged. As a result, the power generation torque (load due to power generation) increases. Therefore, when the temperature of the internal combustion engine is equal to or lower than a predetermined temperature, the load on the internal combustion engine can be increased and the warm-up can be completed quickly.

Further, since the first storage battery has higher energy efficiency than the second storage battery, waste can be reduced and fuel efficiency can be improved even if the power generation torque is increased.

An electric circuit diagram showing an in-vehicle power supply system. A circuit diagram showing a switch connection state and a current flow. A flowchart showing a warm-up control process. A time chart showing changes in engine temperature. The flowchart which shows the warm-up control process of 2nd Embodiment. The circuit diagram which shows the connection state of a switch and the flow of a current in 2nd Embodiment. The time chart which shows the change of the engine temperature of 2nd Embodiment. The electric circuit diagram which shows the in-vehicle power supply system in another example.

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the present embodiment, in a vehicle traveling with an engine 200 as an internal combustion engine as a drive source, a control device applied to an in-vehicle power supply system 100 that supplies electric power to various devices of the vehicle is embodied. In each of the following embodiments, the parts that are the same or equal to each other are designated by the same reference numerals in the drawings.

(First Embodiment)
As shown in FIG. 1, the in-vehicle power supply system 100 is a dual power supply system having a lithium ion storage battery 11 as a first storage battery and a lead storage battery 12 as a second storage battery, and various storage batteries 11 and 12 are used. It is possible to supply power to the electric load.

The lead storage battery 12 is a well-known general-purpose storage battery. On the other hand, the lithium ion storage battery 11 is a high-density storage battery having a smaller power loss in charging / discharging, a higher output density, and a higher energy density than the lead storage battery 12. The lithium ion storage battery 11 is preferably a storage battery having higher energy efficiency during charging / discharging than the lead storage battery 12. Further, the lead storage battery 12 is a storage battery having a larger storage capacity than the lithium ion storage battery 11. Further, the lithium ion storage battery 11 is a storage battery having a smaller internal resistance than the lead storage battery 12. When the energy efficiency is high, the internal resistance generally tends to be small. Further, the lithium ion storage battery 11 is configured as an assembled battery each having a plurality of cell cells. The rated voltage of each of these storage batteries 11 and 12 is the same, for example, 12V.

Although a specific description by illustration is omitted, the lithium ion storage battery 11 is housed in a storage case and is configured as a battery unit U integrated with a substrate. In FIG. 1, the battery unit U is shown surrounded by a broken line. The battery unit U has external terminals P1 and P2, of which a lead storage battery 12, a second electric load 14, and an alternator 20 are connected to the external terminal P1, and a first electric load 13 is connected to the external terminal P2. It is connected.

The first electric load 13 includes a constant voltage load in which the voltage of the supplied power is required to be constant or fluctuate within a predetermined range. A constant voltage load can also be called a protected load. Specific examples of the constant voltage load include various ECUs such as navigation devices, audio devices, meter devices, and engine ECUs. In this case, by suppressing the voltage fluctuation of the supplied power, unnecessary resets and the like are suppressed in each of the above-mentioned devices, and stable operation can be realized. The first electric load 13 may include a traveling system actuator such as an electric steering device or a brake device. The first electric load 13 may include a general electric load other than the constant voltage load. Further, the voltage supplied to the first electric load 13 is not more than the rated voltage of each of the storage batteries 11 and 12.

On the other hand, the second electric load 14 includes a general electric load. For example, a starter, a seat heater, a defogger, a heater for a defroster of a rear window, and the like can be mentioned. Further, the second electric load 14 may have a required voltage different depending on the driving state, such as a lighting device such as a headlight or a blower motor used for blowing air.

For example, in a blower motor, the rotation speed depends on the voltage applied to the blower motor, and the rotation speed fluctuates depending on the applied voltage. As the rotation speed of the blower motor decreases, the air volume also decreases accordingly. Similarly, lighting devices such as headlights may become unstable due to the applied voltage. Therefore, the lighting device, the blower motor, and the like correspond to an electric load that needs to be applied with a predetermined required voltage. The voltage required to properly operate these electrical loads depends on the drive state. That is, in the blower motor, it depends on whether it is turned on or off, the air volume, and the like. In the lighting device, it depends on whether it is turned on or off, the brightness (brightness), and the like.

The alternator 20 as a generator is mechanically connected to the engine output shaft of the engine 200. The alternator 20 has a power generation function of generating power (fuel power generation) by driving energy of the engine output shaft. Further, the alternator 20 is configured to be able to execute power generation (regenerative power generation) by the rotational energy of the axle (kinetic energy of the vehicle). That is, the alternator 20 is configured to be able to execute power generation (regenerative power generation) using the braking torque of the vehicle. As the generator, a rotary electric machine may be used instead of the alternator 20. As the rotary electric machine, for example, a generator with a motor function having a three-phase AC motor or an inverter as a power conversion device, specifically, an ISG (Integrated Starter Generator) integrated with mechanical and electrical power may be adopted.

Next, the battery unit U will be described. The battery unit U is provided with an electric path L1 connecting the external terminals P1 and P2 and an electric path L2 connecting the connection point N1 on the electric path L1 and the lithium ion storage battery 11 as an electric path in the unit. .. Of these, the electric path L1 is provided with a switch SW2 as a second switch, and the electric path L2 is provided with a switch SW1 as a first switch.

As shown in FIG. 1, in the vehicle-mounted power supply system 100, the lithium ion storage battery 11, the lead storage battery 12, the first electric load 13, and the second electric load 14 are connected in parallel to the alternator 20. .. Further, in the electric path L3, switches SW1 and SW2 are provided on the side of the lithium ion storage battery 11 with respect to the connection point N2 as the first connection point to which the alternator 20 is connected. The electric path L3 is an electric path in which a lithium ion storage battery 11, a lead storage battery 12, a first electric load 13, and a second electric load 14 are connected in parallel.

Further, the alternator 20 is configured so that the lead storage battery 12 can be always energized, and the energization between the alternator 20 and the lead storage battery 12 is not cut off. That is, no switch is provided between the alternator 20 and the lead storage battery 12. Similarly, the alternator 20 is configured to be able to always energize the second electric load 14, and the energization between the alternator 20 and the second electric load 14 is not cut off.

On the other hand, a switch SW2 is provided between the alternator 20 and the first electric load 13. The switch SW2 is located between the connection point N2 of the alternator 20 and the connection point N3 (external terminal P2) as the second connection point with the first electric load 13 in the electric path L3, and is a lithium ion storage battery. It is provided on the side of the alternator 20 with respect to the connection point N1 of 11. That is, the first electric load 13 and the alternator 20 are connected in parallel to the lithium ion storage battery 11, and the switch SW2 is provided on the alternator 20 side of the connection point N1 of the lithium ion storage battery 11. The switch SW1 is provided on the side of the lithium ion storage battery 11 with respect to the connection point N1.

Further, the in-vehicle power supply system 100 includes an ECU 50 as a control device. The ECU 50 is an electronic control device including a well-known microcomputer including a CPU, ROM, RAM, flash memory, and the like. The ECU 50 is configured to be able to acquire various information. For example, the ECU 50 acquires (inputs) driver operation information from various sensors such as an accelerator sensor that detects an accelerator operation amount and a brake sensor that detects a brake operation amount of a brake pedal. Further, the ECU 50 acquires information (vehicle speed, etc.) about the vehicle from various sensors such as a vehicle speed sensor. Further, the ECU 50 acquires the engine water temperature from the water temperature sensor that detects the temperature of the engine cooling water. Further, the ECU 50 acquires an SOC (State Of Charge) indicating the amount of electricity stored in each of the storage batteries 11 and 12.

Further, the ECU 50 acquires the generated voltage detected from the voltage detection circuit 21a that detects the generated voltage of the alternator 20. In the present embodiment, one end of the voltage detection circuit 21a is connected between the lead storage battery 12 and the alternator 20, and the other end is grounded. That is, it can be said that the voltage detection circuit 21a detects the voltage on the electric path L3 and also detects the terminal voltage of the lead storage battery 12. If the generated voltage of the alternator 20 can be detected, the voltage detection circuit 21a may be connected anywhere. For example, it may be connected to any of the electric paths L3.

Further, the ECU 50 acquires the generated current detected from the current detection circuit 21b that detects the generated current of the alternator 20. The current detection circuit 21b is connected so as to be in parallel with the switch SW2, and the current passing through the switch SW2, that is, the current flowing through the electric path L1 is detected. If the generated current of the alternator 20 can be detected, the current detection circuit 21b may be connected anywhere. For example, if it is detected only when the switch SW2 is in the ON state, it may be connected to the switch SW1 in parallel.

Then, the ECU 50 executes various controls based on the acquired various information. For example, the ECU 50 controls the states (on, off) of the switches SW1 to SW2 based on the SOCs of the storage batteries 11 and 12. Further, for example, the ECU 50 controls the alternator 20 based on the acquired power generation voltage, power generation current, and the like. Further, the ECU 50 controls the engine 200 based on the vehicle speed, driver operation information, and the like.

By the way, it is necessary to promptly complete the warm-up during the cold drive of the engine 200. In order to complete the warm-up promptly, the engine load may be increased to increase the output torque of the engine 200. When increasing the output torque, the surplus output torque (output torque that is not used for vehicle running or the like) may be used for power generation of the alternator 20. That is, by controlling the alternator 20, the load by the alternator 20 may be increased to increase the generated current.

Since this generated power is charged to the storage batteries 11 and 12 or supplied to the electric loads 13, 14 and the like, the surplus output torque is not wasted. In the following, among the output torques of the engine 200, the output torque used for power generation of the alternator 20 is referred to as a power generation torque, and other output torques, for example, the torque required to appropriately drive the vehicle. Etc. are collectively referred to as drive torque. The drive torque includes not only the torque used for traveling (that is, transmitted to the axle) but also the torque used for the compressor and the like.

In order to complete warm-up quickly, it is desirable to increase the engine load as much as possible. Therefore, as shown in FIG. 1, the ECU 50 is provided with functions as a generator control unit 51, a power supply control unit 52, and a load control unit 53. Various functions are realized by the CPU executing a program stored in various memories or the like. It should be noted that these functions may be realized by an electronic circuit which is hardware, or at least a part thereof may be realized by software, that is, a process executed on a computer. Hereinafter, these functions will be described in detail.

The ECU 50 as the generator control unit 51 uses the alternator 20 to generate electricity by using the output torque of the engine 200 when the engine 200 is being driven and the temperature of the engine 200 is equal to or lower than a predetermined temperature. Control. That is, the ECU 50 controls the alternator 20 so that power generation is performed by utilizing the output torque of the engine 200 during the cold drive of the engine 200. Whether or not the temperature of the engine 200 is equal to or lower than the predetermined temperature is determined by the ECU 50 based on the engine cooling water temperature acquired from the water temperature sensor.

By the way, in order to increase the power generation torque, it is necessary to increase the power generation current of the alternator 20. Then, when the lithium ion storage battery 11 is energized to the alternator 20 in the electric circuit of the vehicle-mounted power supply system 100 as in the present embodiment, the energization between the alternator 20 and the lithium ion storage battery 11 is cut off. Moreover, the combined resistance in the electric circuit is lower than that in the case where only the alternator 20 and the lead storage battery 12 are energized. That is, when the lithium ion storage battery 11 having an internal resistance lower than that of the lead storage battery 12 and the lead storage battery 12 are electrically connected in parallel to the alternator 20, only the lead storage battery 12 is connected to the alternator 20. On the other hand, the combined resistance is lower than when it is connected.

Then, by lowering the combined resistance of the electric circuit of the vehicle-mounted power supply system 100, the generated current can easily flow from the alternator 20. That is, the ECU 50 can increase the power generation current to increase the power generation torque. The combined resistance in the electric circuit of the in-vehicle power supply system 100 is determined by the internal resistance of the storage batteries 11 and 12 and the resistance in each of the electric loads 13 and 14.

Therefore, the ECU 50 as the power supply control unit 52 controls the switches SW1 and SW2 so as to energize at least between the alternator 20 and the lithium ion storage battery 11 during the cold drive of the engine 200. That is, during the cold drive of the engine 200, as shown in FIG. 2A, the switches SW1 and SW2 are both turned on, and the alternator 20 and the lithium ion storage battery 11 are energized. As a result, the generated current of the alternator 20 is supplied to the lithium ion storage battery 11. In this state, the power generation current can be increased as compared with the case where the power generation current is supplied only to the lead storage battery 12 having a higher internal resistance than the lithium ion storage battery 11. In FIG. 2, the current flow is shown by a alternate long and short dash line.

Then, the ECU 50 as the generator control unit 51 controls the alternator 20 so as to increase the power generation torque used by the alternator 20 according to the generated current. Further, the ECU 50 controls the engine 200 so that the output torque increases in response to the increase in the power generation torque (the increase in the engine load).

By the way, when the SOC of the lithium ion storage battery 11 becomes larger than the predetermined SOC, charging becomes unnecessary. For example, when the SOC is close to full charge, charging is unnecessary. Further, in order to utilize the electric power generated by the regenerative power generation without waste, it is desirable to leave a capacity for charging the amount of the regenerative power generation generated by the regenerative power generation.

Therefore, the ECU 50 as the generator control unit 51 controls the alternator 20 so as to stop the power generation when the SOC of the lithium ion storage battery 11 becomes larger (larger) than the predetermined SOC during cold driving. .. The predetermined SOC may be determined based on, for example, the SOC indicating a full charge. Further, for example, the ECU 50 may predict the regenerative power generation amount, and the ECU 50 may determine a predetermined SOC based on the SOC indicating full charge and the predicted regenerative power generation amount. In the present embodiment, the ECU 50 determines the SOC calculated by subtracting the SOC for the predicted regenerative power generation amount from the SOC indicating full charge as a predetermined SOC.

As a method for predicting the amount of regenerative power generation, for example, the ECU 50 may store the SOC history of the lithium ion storage battery 11 in a storage device such as a RAM, and the ECU 50 may predict the SOC based on the SOC history. Specifically, the periodicity may be specified from the history of SOC in the lithium ion storage battery 11, and the regenerative power generation amount may be predicted based on the periodicity. Further, for example, the ECU 50 may acquire the vehicle speed as the vehicle state, predict the deceleration period in which the regenerative power generation is performed based on the vehicle speed, and predict the regenerative power generation amount based on the deceleration period. Further, the deceleration period in which the regenerative power generation is performed may be predicted based on the traveling history, and the regenerative power generation amount may be predicted based on the deceleration period. In addition, the navigation device acquires peripheral traffic information such as travel routes, traffic congestion information, signal information, and peripheral vehicle information (inter-vehicle distance, etc.), and predicts and predicts future driving patterns based on these peripheral traffic information. The amount of regenerative power generation may be predicted based on the driving pattern. The method for predicting the amount of regenerative power generation is not limited to these methods, and any method may be adopted. Further, the predetermined SOC is hereinafter referred to as a first threshold value. As described above, the ECU 50 of the present embodiment has a function as a prediction unit for predicting the amount of regenerative power generation. Further, the ECU 50 has a function as a determination unit for determining a predetermined storage amount according to the regenerative power generation amount.

Then, when the SOC of the lithium ion storage battery 11 exceeds the first threshold value and the power generation is stopped, the ECU 50 as the power supply control unit 52 energizes the lithium ion storage battery 11 and the first electric load 13. The switches SW1 and SW2 are controlled so as to energize between the second electric load 14 and the lithium ion storage battery 11. That is, as shown in FIG. 2B, both the switches SW1 and SW2 are in the ON state. As a result, after the power generation is stopped, power is supplied from the lithium ion storage battery 11 to the first electric load 13 and the second electric load 14. Although the lead-acid battery 12 is also energized with respect to the first electric load 13 and the second electric load 14, electric power is mainly output from the lithium ion storage battery 11 having a lower internal resistance than the lead-acid battery 12.

Then, the ECU 50 as the generator control unit 51 controls the alternator 20 so as to restart the power generation when the SOC of the lithium ion storage battery 11 becomes equal to or less than the second threshold value after the power generation is stopped during the cold drive. The second threshold value is set to a value smaller than the first threshold value based on the first threshold value. For example, a value several percent (eg, 10 percent) lower than the first threshold is set as the second threshold. As a result, charging of the lithium ion storage battery 11 is restarted, and the power generation torque increases. That is, the engine load will increase.

Further, the ECU 50 as the power supply control unit 52 controls the switch SW2 based on the drive state of the second electric load 14 and the state of the lithium ion storage battery 11 when the power generation is stopped during the warm-up. That is, when the SOC of the lithium ion storage battery 11 becomes larger than the first threshold value, the ECU 50 determines the second electric load 14 and the lithium ion storage battery 11 based on the driving state of the second electric load 14 and the state of the lithium ion storage battery 11. The switch SW2 is controlled so as to switch between energization and energization cutoff.

More specifically, the second electric load 14 includes a blower motor having a required voltage different depending on its driving state, such as the blower motor described above. On the other hand, the lithium ion storage battery 11 has a different discharge voltage (terminal voltage) depending on its state. For example, in the low temperature state, the discharge voltage of the lithium ion storage battery 11 is lower than in the high temperature state. Further, when the SOC is low, the discharge voltage is lower than when the SOC is high. Then, the required voltage of the second electric load 14 may increase the discharge voltage of the lithium ion storage battery 11, and in this case, the operation of the second electric load 14 may become unstable.

Therefore, the ECU 50 specifies the required voltage based on the driving state of the second electric load 14, and also specifies the discharge voltage based on the state of the lithium ion storage battery 11. Then, when the required voltage is higher than the discharge voltage, the ECU 50 turns off the switch SW2. That is, as shown in FIG. 2C, the energization between the second electric load 14 and the lithium ion storage battery 11 is cut off. On the other hand, when the required voltage is equal to or lower than the discharge voltage, the switch SW2 is turned on as shown in FIG. 2 (b). That is, the second electric load 14 and the lithium ion storage battery 11 are energized.

Further, when the SOC of the lithium ion storage battery 11 is larger than the first threshold value during cold driving of the engine 200, the ECU 50 as the load control unit 53 has a specific electric load determined in advance among the electric loads 13 and 14. The drive states of the electric loads 13 and 14 are controlled so as to increase the load in. The specific electric load that can change the drive state is predetermined, and the change in the applied voltage does not cause discomfort to the driver even if the operation is changed (it is difficult for the driver to notice). Specifically, the temperature is changed by a defogger, a seat heater, or the like. The electric load that causes discomfort to the driver due to the change in the applied voltage is, for example, a blower motor or a lamp.

Here, the warm-up control process executed by the ECU 50 will be described in more detail with reference to the flowchart shown in FIG. The warm-up control process is executed at predetermined intervals after the engine 200 is started.

The ECU 50 determines whether or not it is necessary to limit the power generation torque so as to be within a predetermined range (step S101). Specifically, the ECU 50 determines whether or not the drive torque is larger than the predetermined torque, and if the determination result is affirmative, the determination result in step S101 is affirmative. That is, when the drive torque is large and there is little room for power generation torque, the determination result in step S101 is affirmed. Further, when the output torque of the ECU 50 is limited, for example, when the catalyst warm-up is being executed and the output torque of the engine 200 is limited (when the output torque cannot be increased), step S101 is performed. Make the judgment result affirmative. Further, when a predetermined traveling mode is set so that the driving torque can be increased immediately (that is, so as to leave a surplus force), the determination result in step S101 is affirmed.

If the determination result in step S101 is affirmative, the ECU 50 limits the power generation torque to be within a predetermined range (step S102). If the determination result in step S101 is negative, or after the processing in step S102, the ECU 50 determines the first threshold value and the second threshold value (step S103). In step S103, as described above, the ECU 50 predicts the regenerative power generation amount, determines the first threshold value based on the SOC indicating that the battery is fully charged, and the predicted regenerative power generation amount, and sets the first threshold value according to the first threshold value. 2 Determine the threshold. By this step S103, the ECU 50 is provided with functions as a prediction unit and a determination unit.

Next, the ECU 50 determines whether or not the temperature of the engine 200 is equal to or lower than a predetermined temperature (step S104). That is, it is determined whether or not the engine 200 is being cold driven. If this determination result is negative, the warm-up control process is terminated.

On the other hand, if the determination result in step S104 is affirmative, the ECU 50 determines whether or not the SOC of the lithium ion storage battery 11 is equal to or less than the first threshold value (step S105). If this determination result is affirmative, the ECU 50 energizes the alternator 20 and the lithium ion storage battery 11 (step S106). That is, as shown in FIG. 2A, both the switches SW1 and SW2 are turned on.

Then, the ECU 50 causes the alternator 20 to generate power (step S107). In step S107, the ECU 50 determines the power generation torque based on the power generation voltage and the power generation current, and controls the alternator 20 so as to be the power generation torque. At that time, the ECU 50 controls the engine 200 so that the output torque corresponds to the power generation torque and the drive torque. Then, after the lapse of a predetermined time, the process of step S104 is executed again.

If the power generation torque is limited within a predetermined range in step S101, the ECU 50 determines the power generation torque within a predetermined range in step S107. When the power generation torque is determined within the predetermined range and the power generation voltage is less than the required voltage of the second electric load 14, the switch SW2 is turned off. As a result, the power generation current to the lithium ion storage battery 11 having a low internal resistance is cut off, so that the power generation voltage can be increased. Incidentally, even when the switch SW2 is turned off, if the generated voltage is less than the required voltage of the second electric load 14, the generated torque is increased beyond a predetermined range.

On the other hand, if the determination result in step S105 is affirmative, the ECU 50 controls the alternator 20 so as to stop the power generation (step S108). Then, the ECU 50 specifies the required voltage based on the drive state of the second electric load 14, and also specifies the discharge voltage based on the state of the lithium ion storage battery 11 (step S109).

Then, the ECU 50 determines whether or not the required voltage is higher than the discharge voltage (step S110). If this determination result is affirmative, the ECU 50 controls the switches SW1 and SW2 so as to cut off the energization between the second electric load 14 and the lithium ion storage battery 11 (step S111). That is, as shown in FIG. 2C, the switch SW1 is turned on and the switch SW2 is turned off.

On the other hand, if the determination result in step S110 is negative, the ECU 50 controls the switches SW1 and SW2 so as to energize between the second electric load 14 and the lithium ion storage battery 11 (step S112). That is, as shown in FIG. 2B, the switch SW1 is turned on and the switch SW2 is turned on.

Further, the ECU 50 controls the drive state of the electric loads 13 and 14 so as to increase the resistance (load) in the specific electric load determined in advance among the electric loads 13 and 14 (step S113). When executing step S113, the ECU 50 determines the electric load 13 so that the required voltage of the predetermined specific electric load among the electric loads 13 and 14 does not become higher than the discharge voltage of the lithium ion storage battery 11. , 14 controls the drive state. Specifically, the drive state of a specific electric load is controlled so that the required voltage is lower than the discharge voltage by a predetermined value.

After a predetermined time has elapsed from the execution of the process of step S111 or step S113, the ECU 50 determines whether or not the SOC of the lithium ion storage battery 11 is equal to or less than the second threshold value (step S114). If this determination result is affirmative, the process proceeds to step S104. On the other hand, if the determination result in step S114 is negative, the ECU 50 determines whether or not the engine 200 is being cold driven (step S115). If this determination result is negative, the ECU 50 ends the warm-up control process. On the other hand, if the determination result in step S115 is affirmative, the ECU 50 executes the process of step S114 again after the lapse of a predetermined time.

The operation when the warm-up control process is executed will be described with reference to FIG. In FIG. 4, the time point T0 will be described on the premise that the storage batteries 11 and 12 are being charged during the cold drive of the engine 200. Further, in FIG. 4, it is assumed that the required voltage of the electric loads 13 and 14 is always equal to or less than the discharge voltage of the lithium ion storage battery 11. Further, at the time point T0, as shown in FIG. 2A, it is premised that the switches SW1 and SW2 are in the ON state, and the storage batteries 11 and 12 are energized with respect to the alternator 20. explain.

At the time point T0, since both the storage batteries 11 and 12 are in a charged state, the power generation current of the alternator 20 increases and the power generation torque increases as compared with the case where only the lead storage battery 12 is charged. Therefore, the engine load can be increased and the output torque of the engine 200 can be increased. That is, the rate of increase in the temperature of the engine 200 (that is, the temperature of the engine cooling water) can be increased.

Then, at the time point T1, the SOC of the lithium ion storage battery 11 reaches the first threshold value, so that the power generation is stopped. Therefore, the engine load becomes small, and the output torque of the engine 200 cannot be increased. That is, the rate of increase in the temperature of the engine 200 becomes low.

At time points T1 to T2, the switches SW1 and SW2 are both turned on, and the lithium ion storage battery 11 supplies electric power to the first electric load 13 and the second electric load 14. Therefore, the SOC of the lithium ion storage battery 11 is lowered.

At the time point T2, when the SOC of the lithium ion storage battery 11 drops to a level equal to or lower than the second threshold value, power generation is restarted and both the storage batteries 11 and 12 are in a charged state. As a result, the power generation current of the alternator 20 increases and the power generation torque increases as compared with the case where only the lead storage battery 12 is charged. Therefore, the engine load can be increased to increase the output torque of the engine 200. That is, the rate of increase in the temperature of the engine 200 (that is, the temperature of the engine cooling water) can be increased. Then, at time point T3, the temperature of the engine 200 reaches a predetermined temperature.

When the lithium ion storage battery 11 is charged and discharged, power loss occurs. Therefore, the engine load is larger when the lithium ion storage battery 11 is charged and discharged than when the lithium ion storage battery 11 is not charged or discharged after the SOC of the lithium ion storage battery 11 reaches the first threshold value. be able to. That is, it is possible to complete the warm-up at an early stage. In FIG. 3, changes in the SOC, power generation torque, and temperature of the engine 200 when the lithium ion storage battery 11 is not charged or discharged after the SOC of the lithium ion storage battery 11 reaches the first threshold value are shown by a single point chain line.

According to the present embodiment described in detail above, the following excellent effects can be obtained.

When the lithium ion storage battery 11 having a low internal resistance is charged, the combined resistance in the electric circuit is low and the generated current from the alternator 20 is large as compared with the case where only the lead storage battery 12 having a high internal resistance is charged. Therefore, the ECU 50 controls the alternator 20 so that power generation is performed by using the output torque of the engine 200 during the cold drive of the engine 200, and energizes between the alternator 20 and the lithium ion storage battery 11. In addition, it was decided to control the switches SW1 and SW2. As a result, the power generation torque (load due to power generation) can be increased. Therefore, when the temperature of the engine 200 is equal to or lower than the predetermined temperature, the load of the engine 200 can be increased to increase the output torque, and the warm-up can be completed quickly. Further, since the lithium ion storage battery 11 has better energy efficiency than the lead storage battery 12, waste can be reduced and fuel efficiency can be improved even if the power generation torque is increased.

When the SOC of the lithium ion storage battery 11 is greater than the first threshold value, the ECU 50 controls the alternator 20 so as to stop the power generation, and stops charging the lithium ion storage battery 11. At that time, the ECU 50 controls the switches SW1 and SW2 so as to energize between the lithium ion storage battery 11 and the first electric load 13 and to energize between the lithium ion storage battery 11 and the second electric load 14. It is supposed to be.

That is, the switches SW1 and SW2 are both turned on, and power is supplied from the lithium ion storage battery 11 not only to the first electric load 13 but also to the second electric load 14.

As a result, when charging is stopped (that is, when power generation is stopped), the lithium ion storage battery 11 is discharged to the second electric load 14 and the first electric load 13, so that the first electric load 13 is discharged. The SOC of the lithium ion storage battery 11 can be reduced at an early stage as compared with the case where the lithium ion storage battery 11 is discharged only. Therefore, charging of the lithium ion storage battery 11 can be resumed at an early stage during warm-up. As a result, even if the power generation torque is once set to zero, warm-up can be completed at an early stage. Further, since the lithium ion storage battery 11 having a low internal resistance is mainly charged and discharged, the energy efficiency is improved and the fuel efficiency can be improved as compared with the case where the lead storage battery 12 is charged and discharged.

When the SOC of the lithium ion storage battery 11 is larger than the first threshold value, the ECU 50 determines between the second electric load 14 and the lithium ion storage battery 11 based on the driving state of the second electric load 14 and the state of the lithium ion storage battery 11. It was decided to control the switch SW2 so as to switch between energization and energization cutoff. Specifically, when the discharge voltage becomes lower than the required voltage due to the driving state of the second electric load 14 and the state of the lithium ion storage battery 11, the operation of the second electric load 14 becomes unstable, so that the switch. It was decided to turn off SW2 and stop the power supply to the second electric load 14. As a result, electric power is supplied from the lead storage battery 12 to the second electric load 14, so that the second electric load 14 can be stably operated.

When the power generation is stopped during warm-up and the lithium ion storage battery 11 is discharged, the ECU 50 controls the drive state of a specific electric load so as to increase the load in the specific electric load among the second electric loads 14. do. As a result, the amount of discharge of the lithium ion storage battery 11 can be increased, charging can be restarted at an early stage, and warm-up can be completed at an early stage. Since the specific electric load is a device that adjusts the temperature and humidity of the air, it is less noticeable to the driver than when the drive state of a lighting device, audio output device, ventilation device, etc. is changed. Does not cause discomfort.

If the regenerated electric power cannot be charged into the highly efficient lithium ion storage battery 11, the electric power may be wasted or the efficiency may be deteriorated. Therefore, the ECU 50 includes a prediction unit for predicting the regenerative power generation amount and a determination unit for determining the first threshold value according to the predicted regenerative power generation amount. As a result, the SOC can be adjusted so that the lithium ion storage battery 11 can be charged with the predicted regenerative power generation amount when the warm-up is completed. Therefore, fuel efficiency can be improved.

The ECU 50 predicts the amount of regenerative power generation based on the history of SOC and the like. As a result, the amount of regenerative power generation can be appropriately predicted, and the lithium ion storage battery 11 can be charged without excess or deficiency.

When the drive torque is larger than the predetermined torque or the output torque is limited, the ECU 50 limits the power generation torque to be within the predetermined range (steps S101 and S102). As a result, when warming up, it is possible to prevent the power generation torque from becoming large and the drive torque from becoming small, and to drive the vehicle appropriately.

(Second Embodiment)
Next, the control device of the second embodiment will be described. In the second embodiment, a part of the functions of the ECU 50 and the warm-up control process in the first embodiment are changed. For example, in the second embodiment, the ECU 50 does not stop the power generation and turns off the switch SW2 when the SOC of the lithium ion storage battery 11 exceeds the first threshold value during the cold drive of the engine 200. Further, when the SOC of the lithium ion storage battery 11 becomes larger than the first threshold value during the cold driving of the engine 200, the driving state thereof is not changed so as to increase the required voltage in a specific electric load. In the following, the parts that are the same or equal to each other in each embodiment are designated by the same reference numerals, and the description thereof will be referred to for the portions having the same reference numerals.

The warm-up control process in the second embodiment will be described with reference to FIG. The warm-up control process is executed at predetermined intervals after the engine 200 is started. Since the processes of steps S101 to S107 in the warm-up control process of the second embodiment are the same as those of the first embodiment, the description thereof will be omitted.

If the determination result in step S105 is affirmative, the ECU 50 controls the switches SW1 and SW2 so as to cut off the energization between the second electric load 14 and the lithium ion storage battery 11 (step S208). That is, as shown in FIG. 6, the switch SW1 is turned on and the switch SW2 is turned off. As a result, the generated current of the alternator 20 is supplied to the lead storage battery 12 and the second electric load 14. On the other hand, electric power is supplied from the lithium ion storage battery 11 to the first electric load 13.

After a predetermined time has elapsed from the execution of the process of step S208, the ECU 50 determines whether or not the SOC of the lithium ion storage battery 11 is equal to or less than the second threshold value (step S209). If this determination result is affirmative, the process proceeds to step S104. On the other hand, if the determination result in step S209 is negative, the ECU 50 determines whether or not the engine 200 is being cold driven (step S210). If this determination result is negative, the ECU 50 ends the warm-up control process. On the other hand, if the determination result in step S210 is affirmative, the ECU 50 executes the process of step S209 again after the lapse of a predetermined time.

The operation when the warm-up control process is executed will be described with reference to FIG. 7. In FIG. 7, the time point T10 will be described on the premise that the storage batteries 11 and 12 are being charged during the cold drive of the engine 200. Further, at the time point T10, as shown in FIG. 2A, it is premised that the switches SW1 and SW2 are in the ON state, and the storage batteries 11 and 12 are energized with respect to the alternator 20. explain.

At the time point T10, since both the storage batteries 11 and 12 are in a charged state, the power generation current of the alternator 20 increases and the power generation torque increases as compared with the case where only the lead storage battery 12 is charged. Therefore, the engine load can be increased and the output torque of the engine 200 can be increased. That is, the rate of increase in the temperature of the engine 200 (that is, the temperature of the engine cooling water) can be increased.

Then, at the time point T11, when the SOC of the lithium ion storage battery 11 reaches the first threshold value, the switch SW1 is turned on and the switch SW2 is turned off. As a result, as shown in FIG. 6, the generated current of the alternator 20 is supplied to the lead storage battery 12 and the second electric load 14. On the other hand, power is supplied from the lithium ion storage battery 11 to the first electric load 13. Therefore, the engine load becomes small, and the output torque of the engine 200 cannot be increased. That is, the rate of increase in the temperature of the engine 200 becomes low.

At the time points T11 to T12, the switch SW1 is turned on and the switch SW2 is turned off, so that the lithium ion storage battery 11 supplies electric power to the first electric load 13. Therefore, the SOC of the lithium ion storage battery 11 is lowered. The lead storage battery 12 is continuously charged.

When the SOC of the lithium ion storage battery 11 drops to the second threshold value or less at the time point T12, power generation is restarted and both the storage batteries 11 and 12 are in a charged state. As a result, the power generation current of the alternator 20 increases and the power generation torque increases as compared with the case where only the lead storage battery 12 is charged. Therefore, the engine load can be increased to increase the output torque of the engine 200. That is, the rate of increase in the temperature of the engine 200 (that is, the temperature of the engine cooling water) can be increased. Then, at the time point T13, the temperature of the engine 200 reaches a predetermined temperature.

According to the second embodiment described in detail above, the following excellent effects can be obtained.

When the SOC of the lithium ion storage battery 11 is more than the first threshold value, charging becomes unnecessary and charging is stopped. Then, when the switch SW2 is turned off and charging is stopped, the first electric load 13 and the lithium ion storage battery 11 are energized (that is, the switch SW1 is turned on) to the first electric load 13. I am trying to discharge. As a result, in order to reduce the SOC of the lithium ion storage battery 11, the lithium ion storage battery 11 can be recharged during warm-up. Therefore, warm-up can be completed at an early stage.

Further, even when the switch SW2 is turned off and the charging of the lithium ion storage battery 11 is stopped, the alternator 20 generates electric power for charging the lead storage battery 12. Therefore, the power generation torque can be generated to increase the engine load, and the warm-up can be completed at an early stage.

(Other embodiments)
The embodiment is not limited to the above embodiment, and may be carried out as follows, for example. In the following, the parts that are the same or equal to each other in each embodiment are designated by the same reference numerals, and the description thereof will be referred to for the portions having the same reference numerals.

-In the first embodiment, when the SOC of the lithium ion storage battery 11 becomes larger than the first threshold value during the cold drive of the engine 200 and the power generation is stopped, the required voltage of a specific electric load is increased. , It is not necessary to change the driving state. That is, the process of step S113 may be omitted.

-In the first embodiment, the driving state may be changed so as to increase the required voltage of a specific electric load during power generation. Thereby, the power generation torque and the output torque can be further increased.

In the above embodiment, when the SOC of the lithium ion storage battery 11 becomes equal to or less than the second threshold value after discharging, the process is again shifted to the process of step S104 and charging is restarted, but after a predetermined time has elapsed, the lithium ion storage battery Charging to 11 may be resumed.

-In the above embodiment, the method of determining the second threshold value may be arbitrarily changed. For example, the ECU 50 may determine the second threshold value based on the first threshold value and the temperature of the engine 200. More specifically, when the difference between the temperature until the warm-up is completed and the temperature of the engine 200 at the present time is small, a large value may be determined as the second threshold value as compared with the case where the difference is large. .. That is, the difference between the first threshold value and the second threshold value may be reduced, and a value close to the first threshold value may be determined as the second threshold value. In this case, it is desirable to redetermine the second threshold value every predetermined time. As a result, when the warm-up is completed, the SOC of the lithium ion storage battery 11 can be brought close to the first threshold value. Therefore, the warm-up can be accelerated and the electric power obtained by the regenerative power generation can be charged to the lithium ion storage battery 11 without excess or deficiency.

-In the first embodiment, when the power generation is stopped, the switch SW1 may be always turned on and the switch SW2 may be turned off. As a result, electric power is supplied from the lead storage battery 12 to the second electric load 14.

-In the above embodiment, it is not necessary to limit the power generation torque. That is, steps S101 and S102 may be omitted.

-In the above embodiment, the SOC indicating full charge may be set as the first threshold value.

-In the above embodiment, a device other than the blower motor may be adopted as the electric load for which a predetermined required voltage needs to be applied. For example, it may be a lighting device such as a headlight whose brightness changes depending on a voltage. For example, it may be an air conditioner.

-In the above embodiment, the function of the ECU 50 may be provided separately in a plurality of ECUs. For example, the generator control unit 51, the power supply control unit 52, and the load control unit 53 may be provided in different ECUs. In this case, each ECU needs to communicate with each other to exchange information.

-In the above embodiment, the configuration of the battery unit U may be changed. For example, as shown in FIG. 8, an electric path L4 in parallel with the electric paths L1 and L2 may be provided, and switches SW3 and SW4 may be provided in the electric path L4. Then, the first electric load 13 is connected to the external terminal P3 connected between the switch SW3 and the switch SW4, the second electric load 14 and the lead storage battery 12 are connected to the external terminal P1, and the alternator 20 is connected to the external terminal P2. And other generators may be connected. As a result, the storage batteries 11 and 12 can be selectively charged and discharged.

11 ... Lithium ion storage battery, 12 ... Lead storage battery, 20 ... Alternator, 50 ... ECU, 51 ... Generator control unit, 52 ... Power supply control unit, 100 ... In-vehicle power supply system, 200 ... Engine, SW1 to SW4 ... Switch.

Claims (8)

An internal combustion engine (200), a generator (20) that generates electricity using the output torque of the internal combustion engine, a first storage battery (11), and a second storage battery (12) having a higher internal resistance than the first storage battery. ), And a switch (SW2) provided in an electric path in which the first storage battery and the second storage battery are connected in parallel to the generator, and a control applied to an in-vehicle power supply system (100). In the device (50)
Power generation that controls the generator so that power generation is performed by using the output torque of the internal combustion engine during cold driving in which the temperature of the internal combustion engine is equal to or lower than a predetermined temperature while the internal combustion engine is being driven. Machine control unit (51) and
A power supply control unit (52) that controls the switch so as to energize at least between the generator and the first storage battery during the cold drive of the internal combustion engine is provided .
The in-vehicle power supply system is provided with a first electric load (13) in which the first storage battery and the second storage battery are connected in parallel in the electric path.
The switch is provided between the first connection point with the generator and the second connection point with the first electric load, and is provided on the side of the generator with respect to the first storage battery.
The power supply control unit energizes the generator and the first storage battery when the storage amount of the first storage battery is equal to or less than the predetermined storage amount during the cold drive of the internal combustion engine. When the storage amount of the first storage battery is larger than the predetermined storage amount, the energization between the generator and the first storage battery is cut off, and the first electric load and the first storage battery are combined. A control device that controls the switch so as to energize the space . When the stored amount of the first storage battery is larger than the predetermined stored amount during the cold drive of the internal combustion engine, the drive state of the first electric load is controlled so as to increase the load in the first electric load. The control device according to claim 1, further comprising a load control unit (53). An internal combustion engine (200), a generator (20) that generates electricity using the output torque of the internal combustion engine, a first storage battery (11), and a second storage battery (12) having a higher internal resistance than the first storage battery. ), And a switch (SW2) provided in an electric path in which the first storage battery and the second storage battery are connected in parallel to the generator, and a control applied to an in-vehicle power supply system (100). In the device (50)
Power generation that controls the generator so that power generation is performed by using the output torque of the internal combustion engine during cold driving in which the temperature of the internal combustion engine is equal to or lower than a predetermined temperature while the internal combustion engine is being driven. Machine control unit (51) and
A power supply control unit (52) that controls the switch so as to energize at least between the generator and the first storage battery during the cold drive of the internal combustion engine is provided .
The in-vehicle power supply system is provided with a first electric load (13) and a second electric load (14) in which the first storage battery and the second storage battery are connected in parallel in the electric path. ,
The switch is between the first connection point (N2) with the generator and the second connection point (N3) with the first electric load, and is closer to the generator than the first storage battery. Provided in
The second electric load is connected to the first storage battery via the switch.
During the cold drive of the internal combustion engine, the generator control unit generates power when the storage amount of the first storage battery is equal to or less than a predetermined storage amount, and generates power when the storage amount is larger than the predetermined storage amount. Control the generator to stop
The power supply control unit energizes the generator and the first storage battery when the storage amount of the first storage battery is equal to or less than the predetermined storage amount during the cold drive of the internal combustion engine. When the amount of electricity stored exceeds the predetermined amount, the switch is energized between the first electric load and the first storage battery, and is energized between the second electric load and the first storage battery. A control device that controls. The second electric load has a required voltage different depending on its driving state, while the first storage battery has a different discharge voltage depending on its driving state.
When the stored amount of the first storage battery is larger than the predetermined stored amount during the cold drive of the internal combustion engine, the power supply control unit is based on the driving state of the second electric load and the state of the first storage battery. The control device according to claim 3, wherein the switch is controlled so as to switch the energization and the energization cutoff between the second electric load and the first storage battery. When the stored amount of the first storage battery is larger than the predetermined stored amount during the cold drive of the internal combustion engine, the load in the first electric load , the second electric load, or both of them is increased. The control device according to claim 3 or 4, wherein the load control unit (53) for controlling the drive state of the first electric load, the second electric load, or both of them is provided. The generator is configured to be capable of regenerative power generation using the braking torque of the vehicle.
The prediction unit (50) that predicts the amount of regenerative power generation,
The control device according to any one of claims 1 to 5, further comprising a determination unit (50) for determining the predetermined storage amount according to the regenerative power generation amount. The control device according to claim 6, wherein the prediction unit predicts the amount of regenerative power generation based on the history of the stored amount of electricity stored in the first storage battery, the running history, the vehicle state, or the predicted running pattern. The generator control unit is used for the generator when the drive torque used to drive the vehicle in the output torque of the internal combustion engine is larger than a predetermined torque or when the output torque is limited. The control device according to any one of claims 1 to 7, which limits the generated torque so as to be within a predetermined range.

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