JP7227718B2 - vehicle power supply - Google Patents

Description

The present invention relates to a vehicle power supply device mounted on a vehicle.

A vehicle power supply device mounted on a vehicle is provided with a storage body such as a lead battery or a lithium ion battery, and is provided with an electric motor such as a motor generator or an ISG (Integrated Starter Generator) (see Patent Document 1). .

JP 2014-36557 A

By the way, in a vehicle having an idling stop function, when a starting condition is satisfied and the engine is restarted, an electric motor such as an ISG is often driven to start and rotate the engine. Thus, in order to properly start the engine using the electric motor, it is necessary to start and rotate the engine with sufficient motor torque. The loss of torque made it difficult to start the engine well.

Therefore, when the temperature of the electric motor rises excessively, it is difficult to restart the engine by the electric motor, so it is considered to prohibit the idling stop control. However, prohibiting idling stop control based only on the temperature of the electric motor is a factor that excessively restricts idling stop control, so it is required to appropriately execute idling stop control.

An object of the present invention is to appropriately perform idling stop control.

A vehicle power supply device according to one embodiment of the present invention is a vehicle power supply device that is mounted on a vehicle, and includes a first power storage unit and an electric load connected to the first power storage unit. a second power supply system including a system, an electric motor coupled to an engine, and a second power storage unit connected to the electric motor; An energization path that connects the first power storage body and the second power storage body in parallel; and idling stop control that stops the engine when a stop condition is satisfied and starts the engine using the electric motor when a start condition is satisfied. and an idling control unit and a prohibition determination unit that prohibits execution of the idling stop control when the temperature of the electric motor exceeds a threshold value, and the prohibition determination unit is controlled as the temperature of the second power storage body decreases. Lower the threshold.
A vehicle power supply device according to one embodiment of the present invention is a vehicle power supply device that is mounted on a vehicle, and includes a first power storage unit and an electric load connected to the first power storage unit. a second power supply system including a system, an electric motor coupled to an engine, and a second power storage unit connected to the electric motor; An energization path that connects the first power storage body and the second power storage body in parallel; and idling stop control that stops the engine when a stop condition is satisfied and starts the engine using the electric motor when a start condition is satisfied. an idling control unit, and a prohibition determination unit that prohibits execution of the idling stop control when the temperature of the electric motor exceeds a threshold, wherein the prohibition determination unit determines that deterioration of the second power storage unit progresses. The threshold is lowered as the
A vehicle power supply device according to one embodiment of the present invention is a vehicle power supply device that is mounted on a vehicle, and includes a first power storage unit and an electric load connected to the first power storage unit. a second power supply system including a system, an electric motor coupled to an engine, and a second power storage unit connected to the electric motor; An energization path that connects the first power storage body and the second power storage body in parallel; and idling stop control that stops the engine when a stop condition is satisfied and starts the engine using the electric motor when a start condition is satisfied. an idling control unit, and a prohibition determination unit that prohibits execution of the idling stop control when the temperature of the electric motor exceeds a threshold, wherein the prohibition determination unit causes the internal resistance of the second power storage unit to increase. The threshold is lowered as the

According to the present invention, there is provided a prohibition determination section that prohibits execution of the idling stop control when the temperature of the electric motor exceeds the threshold. The prohibition determination unit changes the threshold based on at least one of the temperature of the second power storage unit, the degree of deterioration of the second power storage unit, and the internal resistance of the second power storage unit. As a result, idling stop control can be appropriately executed over a wide area.

1 is a schematic diagram showing a configuration example of a vehicle equipped with a vehicle power supply device according to an embodiment of the present invention; FIG. 1 is a circuit diagram simply showing an example of a power supply circuit; FIG. FIG. 4 is a diagram showing an example of a current supply state when the starter generator is controlled to a combustion power generation state; FIG. 4 is a diagram showing an example of a current supply state when the starter generator is controlled to a power generation halt state; FIG. 4 is a diagram showing an example of a current supply state when the starter generator is controlled to a regenerative power generation state; FIG. 4 is a diagram showing an example of a current supply state when the starter generator is controlled to a power running state; FIG. 4 is a diagram showing an example of a current supply state when the starter generator is controlled to a power running state; FIG. 4 is a diagram showing an example of a current supply situation in engine initial start control; FIG. 4 is a diagram showing an example of a current supply situation in lead battery supplementary charging control; 4 is a flow chart showing an example of an execution procedure of ISS determination control 1; 4 is a diagram showing an example of thresholds set in ISS determination control 1; FIG. FIG. 3 is a diagram showing an example of permitted areas and prohibited areas for idling stop control set by ISS determination control 1; 10 is a flowchart showing an example of an execution procedure of ISS determination control 2; FIG. 5 is a diagram showing an example of thresholds set in ISS determination control 2; FIG. 10 is a diagram showing an example of permitted areas and prohibited areas for idling stop control set by ISS determination control 2; 3 is a flowchart showing an example of an execution procedure of ISS determination control 3; FIG. 11 is a diagram showing an example of thresholds set in ISS determination control 3; 3 is a diagram showing an example of permitted areas and prohibited areas for idling stop control set by ISS determination control 3. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Vehicle configuration]
FIG. 1 is a schematic diagram showing a configuration example of a vehicle 11 equipped with a vehicle power supply device 10 according to an embodiment of the present invention. As shown in FIG. 1, a vehicle 11 is equipped with a power unit 13 using an engine 12 as a power source. A starter generator (electric motor) 16 is connected to a crankshaft 14 of the engine 12 via a belt mechanism 15 . A transmission mechanism 18 is connected to the engine 12 via a torque converter 17, and wheels 20 are connected to the transmission mechanism 18 via a differential mechanism 19 and the like.

A starter generator 16 connected to the engine 12 is a so-called ISG (Integrated Starter Generator) that functions as a generator and an electric motor. The starter generator 16 functions not only as a generator driven by the crankshaft 14 but also as an electric motor that drives the crankshaft 14 . For example, when restarting the engine 12 in idling stop control, or when assisting the engine 12 during starting or accelerating, the starter generator 16 is controlled to a power running state and the starter generator 16 functions as an electric motor.

The starter generator 16 has a stator 30 with stator coils and a rotor 31 with field coils. The starter generator 16 is also provided with an ISG controller 32 comprising an inverter, a regulator, a microcomputer, various sensors, etc., in order to control the energization of the stator coil and field coils. By controlling the energized states of the field coils and stator coils with the ISG controller 32, the power generation voltage, power generation torque, power running torque, etc. of the starter generator 16 can be controlled. Further, the starter generator 16 is provided with a temperature sensor 33 for detecting temperature.

The power unit 13 is also provided with a starter motor 40 for starting and rotating the engine 12 . The pinion 41 of the starter motor 40 is movable between a projecting position where it meshes with the ring gear 42 of the torque converter 17 and a retracted position where it disengages from the ring gear 42 . As will be described later, when the passenger presses the starter button 43, the starter relay 44 that controls the energization of the starter motor 40 is switched to the ON state. As a result, the starter motor 40 is energized via the starter relay 44, and the pinion 41 of the starter motor 40 moves to the projecting position and rotates. In order to control the starter motor 40 via the starter relay 44, the vehicle 11 is provided with an engine controller 45 comprising a microcomputer or the like. The engine controller 45 not only controls the starter relay 44, but also controls engine accessories 46 such as a throttle valve, an injector and an ignition device.

As described above, the illustrated vehicle 11 is provided with the starter generator 16 and the starter motor 40 . When the engine 12 is restarted with the idling stop control, that is, when the engine 12 is stopped when the stop condition is satisfied while the engine is running, and when the start condition is satisfied while the engine is stopped and the engine 12 is restarted. , the engine 12 is started and rotated using the starter generator 16 . On the other hand, when the control system of the vehicle 11 is started and the engine 12 is started first, that is, when the engine 12 is started by the driver's operation of the starter button, the starter motor 40 is used to start the engine 12. .

[Power supply circuit]
The power supply circuit 50 included in the vehicle power supply device 10 will be described. FIG. 2 is a circuit diagram simply showing an example of the power supply circuit 50. As shown in FIG. As shown in FIG. 2, the power supply circuit 50 includes a lead battery (first power storage unit) 51 electrically connected to the starter generator 16 and a lithium ion battery electrically connected to the starter generator 16 in parallel. (second power storage body) 52; In order to discharge the lithium ion battery 52 positively, the terminal voltage of the lithium ion battery 52 is designed to be higher than the terminal voltage of the lead battery 51 . Moreover, the internal resistance of the lithium ion battery 52 is designed to be smaller than the internal resistance of the lead battery 51 in order to actively charge and discharge the lithium ion battery 52 .

A positive line 53 is connected to the positive terminal 16a of the starter generator 16, a positive line 54 is connected to the positive terminal 52a of the lithium ion battery 52, and a positive line 55 is connected to the positive terminal 51a of the lead battery 51. 56 are connected. These positive lines 53 , 54 , 56 are connected to each other via a connection point 57 . A negative line 58 is connected to the negative terminal 16b of the starter generator 16, a negative line 59 is connected to the negative terminal 52b of the lithium ion battery 52, and a negative line 60 is connected to the negative terminal 51b of the lead battery 51. be. These negative lines 58 , 59 , 60 are connected to each other via a reference potential point 61 .

As shown in FIG. 1 , a positive electrode line 62 is connected to the positive electrode line 55 of the lead battery 51 . An electric device group 64 including electric devices (electric loads) 63 such as various actuators and various controllers is connected to the positive electrode line 62 . A battery sensor 65 is provided on the negative electrode line 60 of the lead battery 51 . The battery sensor 65 has a function of detecting the charge/discharge status of the lead battery 51 . The charging/discharging status of the lead battery 51 includes, for example, the charging/discharging current of the lead battery 51, the terminal voltage, the state of charge SOC, and the like.

The power supply circuit 50 is also provided with a first power supply system 71 comprising a lead battery 51 and an electrical device 63 , and a second power supply system 72 comprising a lithium ion battery 52 and a starter generator 16 . The lead battery 51 and the lithium ion battery 52 are connected in parallel with each other via a positive electrode line (energization path) 56 provided between the first power supply system 71 and the second power supply system 72 . The positive electrode line 56 is provided with a power fuse 73 that is blown by an excessive current, and a first switch SW1 that is controlled to be turned on and off. A positive electrode line 54 of the lithium ion battery 52 is provided with a second switch SW2 that is controlled to be turned on and off.

By controlling the switch SW1 to the ON state, the first power system 71 and the second power system 72 can be connected to each other. The two power supply systems 72 can be separated from each other. By controlling the switch SW2 to the ON state, the starter generator 16 and the lithium ion battery 52 can be connected to each other. can be separated from each other.

These switches SW1 and SW2 may be switches composed of semiconductor elements such as MOSFETs, or may be switches that mechanically open and close contacts using electromagnetic force or the like. The ON state of the switches SW1 and SW2 means a energized state or conductive state in which they are electrically connected. means state. The switches SW1 and SW2 are also called relays or contactors.

As shown in FIG. 1, the power supply circuit 50 is provided with a battery module 74 . This battery module 74 has a lithium ion battery 52 and switches SW1 and SW2. Also, the battery module 74 has a battery controller 75 comprising a microcomputer, various sensors, and the like. Further, the battery module 74 includes a temperature sensor 76 that detects the temperature of the lithium ion battery 52, a current sensor 77 that detects the charge/discharge current of the lithium ion battery 52, and a voltage sensor 78 that detects the terminal voltage of the lithium ion battery 52. is provided. The battery controller 75 has a function of calculating the state of charge SOC, the state of deterioration SOH, the internal resistance Rlib, and the like of the lithium ion battery 52 based on information transmitted from various sensors. The battery controller 75 also has a function of controlling the switches SW1 and SW2 based on the state of charge SOC of the lithium ion battery 52 and the like. The state of charge SOC (State Of Charge) is the ratio of the amount of charge to the design capacity of the battery. In other words, the state of charge SOC is the ratio of the amount of electricity remaining to the fully charged capacity of the battery.

[Control system]
As shown in FIG. 1, the vehicle power supply device 10 has a main controller 80 such as a microcomputer for controlling the power unit 13, the power supply circuit 50, and the like in cooperation with each other. The main controller 80 has an engine control section 81 that controls the engine 12, an ISG control section 82 that controls the starter generator 16, and a switch control section 83 that controls the switches SW1 and SW2. The main controller 80 also has an idling control section 84 that executes idling stop control, which will be described later, and an assist control section 85 that executes motor assist control, which will be described later. Furthermore, the main controller 80 has a prohibition determination unit 86 and the like that execute idling stop determination control, which will be described later.

The main controller 80 and the controllers 32, 45, and 75 described above are connected to each other so as to be communicable with each other via an in-vehicle network 87 such as CAN or LIN. The main controller 80 controls the power unit 13, power supply circuit 50, etc. based on information from various controllers and various sensors. The main controller 80 controls the starter generator 16 via the ISG controller 32 and controls the switches SW1 and SW2 via the battery controller 75 . The main controller 80 also controls the engine 12 and the starter motor 40 via the engine controller 45 .

[Starter generator power generation control]
Next, power generation control of the starter generator 16 by the main controller 80 will be described. The ISG control unit 82 of the main controller 80 outputs a control signal to the ISG controller 32 to control the starter generator 16 to the power generation state or the power running state. For example, when the state of charge SOC of the lithium ion battery 52 decreases, the ISG control unit 82 increases the power generation voltage of the starter generator 16 and controls the combustion power generation state. The power generation voltage of the generator 16 is lowered to control the power generation halt state. In addition, in each drawing after FIG. 3 which will be described later, “ISG” means the starter generator 16 .

FIG. 3 is a diagram showing an example of the current supply state when the starter generator 16 is controlled to the combustion power generation state. The combustion power generation state of the starter generator 16 is a state in which the starter generator 16 generates power with engine power, that is, a state in which the starter generator 16 generates power by burning fuel in the engine. For example, when the state of charge SOC of the lithium ion battery 52 is below a predetermined lower limit, the starter generator 16 is caused to generate power by the engine power in order to charge the lithium ion battery 52 and increase the state of charge SOC. Thus, when the starter generator 16 is controlled to the combustion power generation state, the generated voltage of the starter generator 16 is raised above the terminal voltages of the lead battery 51 and the lithium ion battery 52 . As a result, as indicated by black arrows in FIG. is slowly charged.

FIG. 4 is a diagram showing an example of the current supply state when the starter generator 16 is controlled to the power generation suspension state. For example, when the state of charge SOC of the lithium ion battery 52 exceeds a predetermined upper limit value, the power generation of the starter generator 16 using engine power is suspended in order to actively discharge the lithium ion battery 52 . In this way, when the starter generator 16 is controlled to the power generation suspended state, the generated voltage of the starter generator 16 is lowered below the terminal voltages of the lead battery 51 and the lithium ion battery 52 . As a result, current is supplied from the lithium-ion battery 52 to the electrical equipment group 64, as indicated by the black arrow in FIG. can be done. It should be noted that the voltage generated by the starter generator 16 in the power generation suspension state may be any voltage that discharges the lithium ion battery 52 . For example, the generated voltage of the starter generator 16 may be controlled to 0V, or the generated voltage of the starter generator 16 may be controlled to be higher than 0V.

As described above, the ISG control unit 82 of the main controller 80 controls the starter generator 16 to the combustion power generation state or the power generation suspension state based on the state of charge SOC. It is required to improve the performance. Therefore, when the vehicle decelerates, the power generation voltage of the starter generator 16 is raised, and the starter generator 16 is controlled to the regenerative power generation state. As a result, since the power generated by the starter generator 16 can be increased, the kinetic energy can be positively converted into electrical energy and recovered, and the energy efficiency of the vehicle 11 can be enhanced to improve fuel efficiency. can. Whether or not to execute such regenerative power generation is determined based on the operating conditions of the accelerator pedal and the brake pedal. That is, the starter generator 16 is controlled to the regenerative power generation state during deceleration when the accelerator pedal is released or when the brake pedal is depressed.

Here, FIG. 5 is a diagram showing an example of the current supply state when the starter generator 16 is controlled to the regenerative power generation state. When the starter generator 16 is controlled to the regenerative power generation state, the power generation voltage of the starter generator 16 is raised above that in the combustion power generation state described above. As a result, a large current is supplied from the starter generator 16 to the lithium ion battery 52 and the lead battery 51, as indicated by black arrows in FIG. charged. Moreover, since the internal resistance of the lithium ion battery 52 is smaller than the internal resistance of the lead battery 51 , most of the generated current is supplied to the lithium ion battery 52 .

As shown in FIGS. 3 to 5, the switches SW1 and SW2 are kept on when the starter generator 16 is controlled in the combustion power generation state, the regenerative power generation state, and the power generation suspension state. In other words, in the vehicle power supply device 10, charging and discharging of the lithium ion battery 52 can be controlled only by controlling the voltage generated by the starter generator 16 without performing switching control of the switches SW1 and SW2. As a result, not only can the charging and discharging of the lithium ion battery 52 be easily controlled, but also the durability of the switches SW1 and SW2 can be improved.

[Engine restart under idling stop control]
An idling control unit 84 of the main controller 80 executes idling stop control to automatically stop and restart the engine 12 . The idling control unit 84 stops the engine 12 by cutting fuel or the like when a predetermined stop condition is satisfied while the engine is running. 16 to restart the engine 12. The conditions for stopping the engine 12 include, for example, that the vehicle speed is below a predetermined value and that the brake pedal is depressed. Further, the conditions for starting the engine 12 include, for example, that the brake pedal is released and that the accelerator pedal is started to be depressed. Note that the idling control unit 84 outputs control signals to the engine control unit 81 and the ISG control unit 82 to control the engine 12 and the starter generator 16 when executing the idling stop control.

Further, the idling control unit 84 controls the starter generator 16 to the power running state to start and rotate the engine 12 when the starting condition is satisfied while the engine is stopped by the idling stop control. Here, FIG. 6 is a diagram showing an example of the current supply state when the starter generator 16 is controlled to the power running state. As shown in FIG. 6, when the starter generator 16 is controlled to be in the power running state when the engine is restarted under the idling stop control, the switch SW1 is turned off and the switch SW2 is turned on. That is, when the engine 12 is started and rotated by the starter generator 16, the switch SW1 is switched to the OFF state, and the first power supply system 71 and the second power supply system 72 are disconnected from each other. As a result, even when a large current is supplied from the lithium-ion battery 52 to the starter generator 16, it is possible to prevent a momentary voltage drop in the electrical equipment group 64 of the first power supply system 71. 64 etc. can function normally.

[Motor assist control]
The assist control unit 85 of the main controller 80 controls the starter generator 16 to the power running state at the time of start or acceleration, and executes motor assist control for assisting the engine 12 with the starter generator 16 . Note that the assist control unit 85 outputs a control signal to the ISG control unit 82 to control the starter generator 16 when executing the motor assist control.

Here, FIG. 7 is a diagram showing an example of the current supply state when the starter generator 16 is controlled to the power running state. As shown in FIG. 7, when the starter generator 16 is controlled to the power running state in accordance with the motor assist control, both the switches SW1 and SW2 are controlled to be on. In this way, when the engine 12 is assisted by the starter generator 16, both the lead battery 51 and the lithium ion battery 52 are connected to the electric device group 64 by turning on the switches SW1 and SW2. there is As a result, the power supply voltage of the electric device group 64 can be stabilized, and the reliability of the vehicle power supply device 10 can be improved.

As described above, when the engine is restarted by the starter generator 16, the switch SW1 is switched off, while when the starter generator 16 assists the motor, the switch SW1 is kept on. In other words, engine restart is a situation in which the stopped engine 12 is started to rotate by the starter generator 16, and the power consumption of the starter generator 16 is likely to increase. On the other hand, the motor-assisted state is a state in which the rotating engine 12 is auxiliary driven by the starter generator 16, and a state in which the power consumption of the starter generator 16 is suppressed. As described above, in the motor assist control, since the power consumption of the starter generator 16 is suppressed, even if the switch SW1 is kept on, a large current does not flow from the lead battery 51 to the starter generator 16. The power supply voltage of the electrical equipment group 64 can be stabilized.

[Engine initial start control, lead battery supplementary charge control]
Subsequently, the engine initial start control for starting the engine 12 using the starter motor 40 will be described, and then the lead battery supplementary charge control by the starter generator 16 after the engine initial start will be described. Here, FIG. 8 is a diagram showing an example of the current supply state in the engine initial start control. Also, FIG. 9 is a diagram showing an example of a current supply state in the lead battery auxiliary charging control.

When the control system of the vehicle 11 is started and the engine 12 is started first, that is, when the engine 12 is started by operating the starter button, the starter motor 40 performs starting rotation of the engine 12 . In this engine initial start control, as shown in FIG. 8, the switch SW1 is controlled to be off, the switch SW2 is controlled to be off, and the starter relay 44 is controlled to be on. As a result, current is supplied from the lead battery 51 to the starter motor 40, and the engine 12 is started by rotating the starter motor 40. FIG.

When the engine 12 is started by the starter motor 40 in this manner, the starter relay 44 is switched to the OFF state, the switch SW1 is switched to the ON state, and the starter generator 16 is switched to the combustion power generation state, as shown in FIG. controlled. That is, when the engine 12 is started, the switch SW1 is switched to the ON state while the switch SW2 is kept OFF, and the starter generator 16 is controlled to the combustion power generation state. As a result, the lead battery 51 can be positively charged by the starter generator 16, and the state of charge SOC of the lead battery 51, which decreases when the vehicle is stopped or when the engine is first started, can be restored.

That is, dark current flows from the lead battery 51 to the electric device group 64 while the vehicle is stopped, and a large current flows from the lead battery 51 to the starter motor 40 when the engine is first started. The state of charge SOC gradually decreases. For this reason, the reduced state of charge SOC of the lead battery 51 is restored by executing the lead battery auxiliary charging control after the engine is first started. The lead battery supplementary charge control may be continued for a predetermined period of time, or may be continued until the state of charge SOC of the lead battery 51 recovers to a predetermined value.

[Idling stop determination control 1]
Next, idling stop determination control 1 (hereinafter referred to as ISS determination control 1) executed by the prohibition determination unit 86 of the main controller 80 will be described. The ISS determination control 1 is control for determining whether or not to prohibit the above-described idling stop control.

As described above, when the engine is restarted due to the idling stop control, the switch SW1 is controlled to be OFF, the switch SW2 is controlled to be ON, and the starter generator 16 is controlled to be power running. Electric power is thereby supplied from the lithium ion battery 52 to the starter generator 16 , and the engine 12 is cranked by the starter generator 16 .

At this time, if the temperature of the starter-generator 16 is excessively high, the motor torque tends to decrease due to an increase in coil resistance, etc., so restarting the engine by the starter-generator 16 may become difficult. Therefore, the main controller 80 determines whether or not to prohibit the execution of the idling stop control by executing the ISS judgment control 1 at predetermined intervals in order to avoid a situation in which restarting of the engine becomes difficult.

FIG. 10 is a flow chart showing an example of the execution procedure of the ISS determination control 1. FIG. FIG. 11 is a diagram showing an example of the threshold value Xa set in ISS determination control 1. In FIG. “ISG temperature” shown in FIG. 10 is the temperature Tisg of the starter generator 16 . Also, “LiB temperature” shown in FIGS. 10 and 11 is the temperature Tlib of the lithium ion battery 52 . A temperature Tisg of the starter generator 16 (hereinafter referred to as starter temperature Tisg) is detected by a temperature sensor 33 provided in the starter generator 16 . Temperature Tlib of lithium ion battery 52 (hereinafter referred to as battery temperature Tlib) is detected by temperature sensor 76 provided in battery module 74 .

As shown in FIG. 10, in step S10, the battery temperature Tlib is read, and in subsequent step S11, the threshold value Xa is set based on the battery temperature Tlib. Here, as shown in FIG. 11, the threshold value Xa set in step S11 is increased as the battery temperature Tlib increases. That is, the threshold value Xa set in step S11 is decreased as the battery temperature Tlib decreases. When the threshold value Xa is set based on the battery temperature Tlib in this manner, the process proceeds to step S12, and the starter temperature Tisg is read.

Subsequently, in step S13, it is determined whether or not the starter temperature Tisg exceeds the threshold value Xa set based on the battery temperature Tlib. If it is determined in step S13 that the starter temperature Tisg exceeds the threshold value Xa, there is a possibility that the motor torque will be insufficient when the engine is restarted. On the other hand, in step S13, when it is determined that the starter temperature Tisg is equal to or lower than the threshold value Xa, since sufficient motor torque is ensured when the engine is restarted, the process proceeds to step S15 to execute the idling stop control. is allowed.

Here, FIG. 12 is a diagram showing an example of permitted regions and prohibited regions of idling stop control set by ISS determination control 1. In FIG. As described above, in the ISS determination control 1, the threshold Xa for comparison with the starter temperature Tisg is set to decrease as the battery temperature Tlib decreases. As a result, the threshold Xa is set low when the battery temperature Tlib is low, as indicated by symbol y1 in FIG. 12, while the threshold Xa is set high when the battery temperature Tlib is high, as indicated by symbol y2. be done. That is, when the battery temperature Tlib is "tb1", "Xa1" is set as the threshold value Xa. Further, when the battery temperature Tlib is "tb2" higher than "tb1", "Xa2" higher than "Xa1" is set as the threshold value Xa.

When the battery temperature Tlib is "tb1", if the starter temperature Tisg exceeds the threshold "Xa1", the motor torque may be insufficient, so the idling stop control is prohibited. On the other hand, when the starter temperature Tisg falls below the threshold value "Xa1", the idling stop control is permitted because the motor torque is sufficiently secured. Further, when the battery temperature Tlib is "tb2", if the starter temperature Tisg exceeds the threshold "Xa2", the motor torque may be insufficient, so the idling stop control is prohibited. On the other hand, when the starter temperature Tisg falls below the threshold "Xa2", the idling stop control is permitted because the motor torque is sufficiently secured. Thus, by increasing or decreasing the threshold value Xa based on the battery temperature Tlib, it is possible to avoid a situation in which restarting of the engine becomes difficult, and to expand the allowable range of the idling stop control.

Here, when the battery temperature Tlib is "tb1" and the starter temperature Tisg is "ta1" as indicated by symbol z1 in FIG. 12, the starter temperature Tisg exceeds the threshold "Xa1" and the engine is Idling stop control is prohibited because there is a risk that the motor torque will be insufficient at the time of starting. However, as indicated by symbol z2, when the battery temperature Tlib has increased to "tb2", even if the starter temperature Tisg is "ta1", the starter temperature Tisg is lower than the threshold "Xa2". , idling stop control is permitted. Furthermore, as indicated by symbol z3, when the starter temperature Tisg has decreased to "ta2", even if the battery temperature Tlib is "tb1", the starter temperature Tisg is lower than the threshold "Xa1". , idling stop control is permitted.

That is, as indicated by symbol z2 in FIG. 12, in a high region where the starter temperature Tisg exceeds the predetermined temperature TA, coil resistance increases, demagnetization of the permanent magnet, and the like are likely to occur, so the motor torque of the starter generator 16 decreases. There is a possibility that it will decrease, and restarting the engine by the starter generator 16 may become difficult. However, as indicated by symbol z2, in the region where the battery temperature Tlib is high, the internal resistance of the lithium ion battery 52 decreases and the discharge current increases. Is possible. Thus, as indicated by symbol z2, even in a region where the starter temperature Tisg is high, when the battery temperature Tlib is in a region where the motor torque is high when the engine is restarted, the motor torque can be secured. Execution of stop control is permitted. That is, in a situation where the motor torque is likely to decrease due to an increase in coil resistance or the like, that is, in a situation where the starter temperature Tisg exceeds the predetermined temperature TA, instead of uniformly prohibiting the execution of the idling stop control, the threshold value according to the battery temperature Tlib Since Xa is changed, idling stop control can be appropriately executed in a wide range.

12, when the battery temperature Tlib is lower than the predetermined temperature TB, the internal resistance of the lithium ion battery 52 increases and the discharge current decreases, so the motor torque of the starter generator 16 may decrease, and restarting the engine by the starter generator 16 may become difficult. However, as indicated by symbol z3, in a region where the starter temperature Tisg is low, an increase in coil resistance or the like is less likely to occur and the motor torque is likely to increase. is possible. In this way, as indicated by symbol z3, even when the battery temperature Tlib is in the low range, when the starter temperature Tisg is in the low range, the motor torque can be ensured when the engine is restarted. Execution of stop control is permitted. That is, in a situation where the motor torque tends to decrease due to a decrease in the supply current from the lithium-ion battery 52, that is, in a situation where the battery temperature Tlib is lower than the predetermined temperature TB, the execution of the idling stop control is not uniformly prohibited, and the battery temperature Tlib Since the threshold value Xa is changed based on the above, the idling stop control can be appropriately executed in a wide range.

[Idling stop determination control 2]
In the ISS determination control 1 described above, the threshold value Xa is changed based on the battery temperature Tlib, but it is not limited to this. Next, idling stop determination control 2 (hereinafter referred to as ISS determination control 2) executed by prohibition determination section 86 of main controller 80 will be described. Note that the ISS determination control 2 is, like the ISS determination control 1 described above, a control for determining whether or not to prohibit the idling stop control. The main controller 80 determines whether or not to prohibit the execution of the idling stop control by executing the ISS determination control 2 at predetermined intervals in order to avoid a situation in which it becomes difficult to restart the engine.

FIG. 13 is a flow chart showing an example of the execution procedure of the ISS determination control 2. FIG. FIG. 14 is a diagram showing an example of threshold value Xb set in ISS determination control 2. In FIG. The "ISG temperature" shown in FIG. 13 is the temperature Tisg of the starter generator 16 (hereinafter referred to as starter temperature Tisg). "LiB-SOH" shown in FIGS. 13 and 14 is SOH (State of Health), which is an indicator of the state of deterioration of the lithium ion battery 52, that is, the state of health. degree). This index SOH is indicated as the current capacity retention rate and voltage retention rate for the initial state of the lithium-ion battery 52 and is periodically calculated by the battery controller 75 . When calculating the index SOH, for example, the following formulas (1) and (2) can be used.
SOH [%]=current storage capacity/initial storage capacity×100 (1)
SOH [%]=current full charge voltage/initial full charge voltage×100 (2)

Since the storage capacity (capacity) decreases as the deterioration of the lithium ion battery 52 progresses, when the index SOH is calculated using equation (1), the index SOH is calculated to be low. Further, as the deterioration of the lithium-ion battery 52 progresses, the full charge voltage, that is, the terminal voltage at full charge, decreases. The index SOH is calculated lower as the deterioration progresses. In other words, when formulas (1) and (2) are used, it means that the deterioration of the lithium ion battery 52 progresses as the index SOH decreases.

As shown in FIG. 13, in step S20, the index SOH is read, and in subsequent step S21, the threshold value Xb is set based on the index SOH. Here, as shown in FIG. 14, the threshold Xb set in step S21 is increased as the index SOH is higher. That is, the threshold Xb set in step S21 is lowered as the index SOH decreases, that is, as the deterioration of the lithium ion battery 52 progresses. When the threshold value Xb is set based on the index SOH in this way, the process proceeds to step S22, and the starter temperature Tisg is read.

Subsequently, in step S23, it is determined whether or not the starter temperature Tisg exceeds the threshold value Xb set based on the index SOH. If it is determined in step S23 that the starter temperature Tisg exceeds the threshold value Xb, there is a possibility that the motor torque will be insufficient when the engine is restarted. On the other hand, when it is determined in step S23 that the starter temperature Tisg is equal to or lower than the threshold value Xb, since sufficient motor torque is ensured when the engine is restarted, the process proceeds to step S25 to execute the idling stop control. is allowed.

Here, FIG. 15 is a diagram showing an example of permitted regions and prohibited regions of idling stop control set by ISS determination control 2. In FIG. As described above, in the ISS determination control 2, the threshold Xb for comparison with the starter temperature Tisg is set to be lowered as the deterioration of the lithium ion battery 52 progresses. As a result, as indicated by symbol y1 in FIG. 15, the threshold Xb is set low when the index SOH is low, while the threshold Xb is set high when the index SOH is high, as indicated by symbol y2. . That is, when the index SOH is "s1", "Xb1" is set as the threshold value Xb. Further, when the index SOH is "s2" which is higher than "s1", "Xb2" which is on the higher temperature side than "Xb1" is set as the threshold value Xb.

When the index SOH is "s1", if the starter temperature Tisg exceeds the threshold "Xb1", the motor torque may be insufficient, so the idling stop control is prohibited. On the other hand, when the starter temperature Tisg falls below the threshold value "Xb1", the idling stop control is permitted because a sufficient motor torque is ensured. Further, when the index SOH is "s2", if the starter temperature Tisg exceeds the threshold "Xb2", the motor torque may be insufficient, so the idling stop control is prohibited. On the other hand, when the starter temperature Tisg falls below the threshold value "Xb2", the idling stop control is permitted because the motor torque is sufficiently secured. Thus, by increasing or decreasing the threshold value Xb based on the index SOH, it is possible to avoid a situation in which restarting of the engine becomes difficult, and to expand the allowable range of the idling stop control.

Here, when the index SOH is "s1" and the starter temperature Tisg is "ta1" as indicated by symbol z1 in FIG. 15, the starter temperature Tisg exceeds the threshold "Xb1" and the engine is restarted. Since there is a possibility that the motor torque may be insufficient at times, the idling stop control is prohibited. However, as indicated by symbol z2, when the index SOH is good "s2", even if the starter temperature Tisg is "ta1", the starter temperature Tisg is below the threshold "Xb2". Idling stop control is permitted. Furthermore, as indicated by symbol z3, when the starter temperature Tisg has decreased to "ta2", the starter temperature Tisg falls below the threshold "Xb1" even if the index SOH is "s1" on the deterioration side. Therefore, idling stop control is permitted.

That is, as indicated by symbol z2 in FIG. 15, in a region where the starter temperature Tisg is higher than the predetermined temperature TA, coil resistance increases, demagnetization of the permanent magnets, and the like are likely to occur. There is a possibility that it will decrease, and restarting the engine by the starter generator 16 may become difficult. However, as indicated by symbol z2, in the region where the index SOH is high, a large amount of discharge current can be extracted from the good lithium-ion battery 52, so that the reduction in motor torque due to the increase in the starter temperature Tisg can be eliminated. is possible. Thus, as indicated by symbol z2, even in a region where the starter temperature Tisg is high, when the index SOH is in a region where the index SOH is high, it is possible to ensure the motor torque when restarting the engine. Allows control execution. That is, in a situation in which the motor torque tends to decrease due to an increase in coil resistance or the like, that is, in a situation in which the starter temperature Tisg exceeds the predetermined temperature TA, the execution of the idling stop control is not uniformly prohibited. is changed, idling stop control can be appropriately executed in a wide area.

15, in a region in which the index SOH is lower than the predetermined value SA, the lithium ion battery 52 deteriorates and the discharge current decreases, so there is a possibility that the motor torque of the starter generator 16 decreases. There is a possibility that restarting the engine by the starter generator 16 may become difficult. However, as indicated by symbol z3, in a region where the starter temperature Tisg is low, it is difficult to increase the coil resistance and the like, and the motor torque tends to increase. It is possible. In this way, as indicated by symbol z3, even when the index SOH is in a low range, when the starter temperature Tisg is in a low range, the motor torque can be ensured when the engine is restarted, so that the idling stop operation can be performed. Allows control execution. That is, in a situation in which the motor torque tends to decrease due to a decrease in the current supplied from the lithium ion battery 52, that is, in a situation in which the index SOH is below the predetermined value SA, the execution of the idling stop control is not uniformly prohibited, but based on the index SOH. Since the threshold value Xb is varied, the idling stop control can be appropriately executed over a wide range.

In the above description, the current capacity retention rate and voltage retention rate with respect to the initial state of the lithium ion battery 52 are used as the index SOH, but the present invention is not limited to this. For example, as the index SOH, the current rate of increase in resistance of the lithium ion battery 52 with respect to the initial state may be used. In this way, when calculating the index SOH using the rate of increase in resistance, it is possible to use, for example, the following equation (3). Since the internal resistance increases as the deterioration of the lithium-ion battery 52 progresses, the index SOH increases as the deterioration of the lithium-ion battery 52 progresses when the index SOH is calculated using equation (3). will be calculated. The method of calculating the index SOH is not limited to the various methods described above, and may be calculated by integrating the charge/discharge current of the lithium ion battery 52, or by integrating the temperature of the lithium ion battery 52. can be calculated by
SOH [%]=current internal resistance/initial internal resistance×100 (3)

[Idling stop determination control 3]
In the above-described ISS determination control 1, the threshold Xa is changed based on the battery temperature Tlib, and in the ISS determination control 2, the threshold Xb is changed based on the index SOH, but the present invention is not limited to this. Next, idling stop determination control 3 (hereinafter referred to as ISS determination control 3) executed by prohibition determination section 86 of main controller 80 will be described. Note that the ISS determination control 3 is, like the ISS determination controls 1 and 2 described above, a control for determining whether or not to prohibit the idling stop control. The main controller 80 determines whether or not to prohibit the execution of the idling stop control by executing the ISS determination control 3 at predetermined intervals in order to avoid a situation where restarting the engine becomes difficult.

FIG. 16 is a flow chart showing an example of the execution procedure of the ISS determination control 3. FIG. FIG. 17 is a diagram showing an example of threshold value Xc set in ISS determination control 3. In FIG. The "ISG temperature" shown in FIG. 16 is the temperature Tisg of the starter generator 16 (hereinafter referred to as starter temperature Tisg). Also, the “LiB internal resistance” shown in FIGS. 16 and 17 is the internal resistance Rlib of the lithium ion battery 52 . Note that the internal resistance Rlib of the lithium ion battery 52 is periodically calculated by the battery controller 75 . This internal resistance Rlib can be calculated using, for example, the terminal voltage and charging/discharging current of the lithium ion battery 52 .

As shown in FIG. 16, in step S30, the internal resistance Rlib is read, and in subsequent step S31, the threshold value Xc is set based on the internal resistance Rlib. Here, as shown in FIG. 17, the threshold Xc set in step S31 is increased as the internal resistance Rlib decreases. That is, the threshold Xc set in step S31 is lowered as the internal resistance Rlib increases. After the threshold value Xc is set based on the internal resistance Rlib in this manner, the process proceeds to step S32, and the starter temperature Tisg is read.

Subsequently, in step S33, it is determined whether or not the starter temperature Tisg exceeds the threshold value Xc set based on the internal resistance Rlib. If it is determined in step S33 that the starter temperature Tisg exceeds the threshold value Xc, there is a possibility that the motor torque will be insufficient when the engine is restarted. On the other hand, when it is determined in step S33 that the starter temperature Tisg is equal to or lower than the threshold value Xc, since sufficient motor torque is ensured when the engine is restarted, the process proceeds to step S35 to execute the idling stop control. is allowed.

Here, FIG. 18 is a diagram showing an example of permitted regions and prohibited regions of idling stop control set by ISS determination control 3. In FIG. As described above, in the ISS determination control 3, the threshold Xc for comparison with the starter temperature Tisg is set to decrease as the internal resistance Rlib increases. As a result, the threshold Xc is set low when the internal resistance Rlib is high, as indicated by symbol y1 in FIG. 18, while the threshold Xc is set high when the internal resistance Rlib is low, as indicated by symbol y2. be done. That is, when the internal resistance Rlib is "r1", "Xc1" is set as the threshold value Xc. Further, when the internal resistance Rlib is "r2" lower than "r1", "Xc2", which is higher than "Xc1", is set as the threshold value Xc.

When the internal resistance Rlib is "r1", if the starter temperature Tisg exceeds the threshold "Xc1", the motor torque may be insufficient, so the idling stop control is prohibited. On the other hand, when the starter temperature Tisg falls below the threshold value "Xc1", the idling stop control is permitted because the motor torque is sufficiently secured. Further, when the internal resistance Rlib is "r2", if the starter temperature Tisg exceeds the threshold "Xc2", the motor torque may be insufficient, so the idling stop control is prohibited. On the other hand, when the starter temperature Tisg falls below the threshold "Xc2", the idling stop control is permitted because the motor torque is sufficiently secured. Thus, by increasing or decreasing the threshold value Xc based on the internal resistance Rlib, it is possible to avoid a situation in which restarting of the engine becomes difficult, and to expand the allowable range of the idling stop control.

Here, as indicated by symbol z1 in FIG. 18, when the internal resistance Rlib is "r1" and the starter temperature Tisg is "ta1", the starter temperature Tisg exceeds the threshold "Xc1" and the engine restarts. Idling stop control is prohibited because there is a risk that the motor torque will be insufficient at the time of starting. However, as indicated by symbol z2, when the internal resistance Rlib has decreased to "r2", even if the starter temperature Tisg is "ta1", the starter temperature Tisg is lower than the threshold "Xc2". , idling stop control is permitted. Furthermore, as indicated by symbol z3, when the starter temperature Tisg has decreased to "ta2", even if the internal resistance Rlib is "r1", the starter temperature Tisg is lower than the threshold "Xc1". , idling stop control is permitted.

That is, as indicated by symbol z2 in FIG. 18, in a region where the starter temperature Tisg is higher than the predetermined temperature TA, coil resistance increases, demagnetization of the permanent magnet, and the like are likely to occur. There is a possibility that it will decrease, and restarting the engine by the starter generator 16 may become difficult. However, as indicated by symbol z2, in the region where the internal resistance Rlib is low, the discharge current of the lithium ion battery 52 increases, so it is possible to eliminate the decrease in motor torque that accompanies the increase in starter temperature Tisg. Thus, as indicated by symbol z2, even in a region where the starter temperature Tisg is high, when the internal resistance Rlib is in a region where the internal resistance Rlib is low, it is possible to ensure the motor torque at the time of restarting the engine. Execution of stop control is permitted. That is, in a situation where the motor torque tends to decrease due to an increase in coil resistance, that is, in a situation where the starter temperature Tisg exceeds the predetermined temperature TA, the execution of the idling stop control is not uniformly prohibited, but the threshold value is determined according to the internal resistance Rlib. Since Xc is varied, idling stop control can be appropriately executed in a wide range.

Further, as indicated by symbol z3 in FIG. 18, in a high region where the internal resistance Rlib exceeds the predetermined value RA, the discharge current of the lithium ion battery 52 decreases, so there is a possibility that the motor torque of the starter generator 16 decreases. , the restart of the engine by the starter generator 16 may become difficult. However, as indicated by symbol z3, in a region where the starter temperature Tisg is low, an increase in coil resistance or the like is less likely to occur and the motor torque is likely to increase. is possible. Thus, as indicated by symbol z3, even if the internal resistance Rlib is in a high region, when the starter temperature Tisg is in a low region, it is possible to secure the motor torque at the time of restarting the engine. Execution of stop control is permitted. That is, in a situation where the motor torque tends to decrease due to a decrease in the supply current from the lithium ion battery 52, that is, in a situation where the internal resistance Rlib exceeds the predetermined value RA, instead of uniformly prohibiting the execution of the idling stop control, the internal resistance Rlib Since the threshold value Xc is changed based on the above, the idling stop control can be appropriately executed in a wide range.

It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. In the above description, the starter generator 16 that functions as both an electric motor and a generator is used as the electric motor connected to the engine 12. However, the present invention is not limited to this, and a motor that functions only as an electric motor may be used. Also, in the above description, the ISS determination controls 1 to 3 are executed separately, but the present invention is not limited to this, and the ISS determination controls 1 to 3 may be executed in combination with each other. For example, the threshold for comparison with the starter temperature Tisg may be changed based on the battery temperature Tlib and the indicator SOH, or may be changed based on the battery temperature Tlib and the internal resistance Rlib. Also, the threshold for comparison with the starter temperature Tisg may be changed based on the indicator SOH and the internal resistance Rlib, or may be changed based on the battery temperature Tlib, the indicator SOH and the internal resistance Rlib. That is, the threshold may be changed based on at least one of battery temperature Tlib, index SOH, and internal resistance Rlib.

In the above description, the switch SW1 is controlled to be in the off state when the engine 12 is restarted with the idling stop control, but it is not limited to this. If the capacity of the lead battery 51 or the lithium ion battery 52 is large and the voltage does not drop significantly when the engine is restarted, both the switches SW1 and SW2 may be controlled to the ON state. Also, in the above description, the lead battery 51 is used as the first power storage body, but the present invention is not limited to this, and other types of batteries and capacitors may be used as the first power storage body. Moreover, although the lithium ion battery 52 is used as the second power storage body, the present invention is not limited to this, and other types of batteries and capacitors may be used as the second power storage body. Also, in the example shown in FIGS. 1 and 2, the switch SW2 is provided in the positive electrode line 54 of the lithium ion battery 52, but it is not limited to this. For example, a switch SW2 may be provided in the negative electrode line 59 of the lithium ion battery 52, as indicated by the dashed line in FIG. Further, in the above description, the main controller 80 is provided with the various control units 81 to 85 and the determination unit 86, but the present invention is not limited to this. Some or all of the various control units 81 to 85 and the determination unit 86 may be provided in another controller.

10 vehicle power supply device 11 vehicle 12 engine 16 starter generator (electric motor)
51 lead battery (first power storage body)
52 Lithium ion battery 56 Positive electrode line (energization path)
63 Electrical Equipment (Electrical Load)
71 First power supply system 72 Second power supply system 84 Idling control unit 86 Prohibition determination unit SW1 First switch SW2 Second switch Tisg Starter temperature (motor temperature)
Tlib Battery temperature (temperature of the second power storage unit)
Rlib internal resistance SOH index (degree of deterioration)
Xa, Xa1, Xa2 Thresholds Xb, Xb1, Xb2 Thresholds Xc, Xc1, Xc2 Thresholds

Claims (4)

A vehicle power supply device mounted on a vehicle,
a first power supply system including a first power storage body and an electric load connected to the first power storage body;
a second power supply system including an electric motor coupled to an engine and a second power storage unit connected to the electric motor;
an energization path provided between the first power supply system and the second power supply system and connecting the first power storage body and the second power storage body in parallel;
an idling control unit that stops the engine when a stop condition is satisfied as idling stop control and starts the engine using the electric motor when a start condition is satisfied;
a prohibition determination unit that prohibits execution of the idling stop control when the temperature of the electric motor exceeds a threshold;
has
the prohibition determination unit lowers the threshold as the temperature of the second power storage body decreases;
Vehicle power supply. A vehicle power supply device mounted on a vehicle,
a first power supply system including a first power storage body and an electric load connected to the first power storage body;
a second power supply system including an electric motor coupled to an engine and a second power storage unit connected to the electric motor;
an energization path provided between the first power supply system and the second power supply system and connecting the first power storage body and the second power storage body in parallel;
an idling control unit that stops the engine when a stop condition is satisfied as idling stop control and starts the engine using the electric motor when a start condition is satisfied;
a prohibition determination unit that prohibits execution of the idling stop control when the temperature of the electric motor exceeds a threshold;
has
The prohibition determination unit lowers the threshold value as the deterioration of the second power storage unit progresses.
Vehicle power supply. A vehicle power supply device mounted on a vehicle,
a first power supply system including a first power storage body and an electric load connected to the first power storage body;
a second power supply system including an electric motor coupled to an engine and a second power storage unit connected to the electric motor;
an energization path provided between the first power supply system and the second power supply system and connecting the first power storage body and the second power storage body in parallel;
an idling control unit that stops the engine when a stop condition is satisfied as idling stop control and starts the engine using the electric motor when a start condition is satisfied;
a prohibition determination unit that prohibits execution of the idling stop control when the temperature of the electric motor exceeds a threshold;
has
the prohibition determination unit lowers the threshold as the internal resistance of the second power storage unit increases;
Vehicle power supply. In the vehicle power supply device according to any one of claims 1 to 3 ,
A first power supply system provided in the conducting path and controlled to be in an ON state for connecting the first power supply system and the second power supply system and an OFF state for separating the first power supply system from the second power supply system. a switch;
a second switch provided in the second power supply system and controlled to be in an ON state for connecting the electric motor and the second power storage unit and an OFF state for disconnecting the electric motor from the second power storage unit;
has
The idling control unit controls the first switch to be off and the second switch to be on when the engine is started using the electric motor.
Vehicle power supply.

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