JP6682383B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device.

  2. Description of the Related Art In recent vehicles such as automobiles, technologies such as charge control (charge / discharge control) that improve fuel efficiency by actively using electric power stored in a battery are widely used.

  In charge control, for example, when the SOC (State Of Charge), which is the ratio of the remaining charge amount to the charge capacity (full charge amount) of the battery, is within a certain charge control range, power generation by the alternator other than during deceleration of the vehicle is performed. Is stopped and electric power is supplied from the battery to an electric load such as a headlight. As a result, the load on the engine can be reduced and fuel consumption can be improved.

  The battery deteriorates as the battery power is used. When control for greatly reducing the terminal voltage (battery voltage) of the battery is performed in a deteriorated state of the battery, for example, charging control or IDS control (idling stop control) is executed, the deterioration of the battery further progresses and the battery The life is shortened. Therefore, when the battery deterioration is determined and the battery is deteriorated, execution of charging control, IDS control, and the like is prohibited.

  In the conventional deterioration determination, the battery voltage (starting voltage) V1 at the start of the starter and the battery voltage (cranking voltage) V2 at the time of cranking are acquired, and the starting voltage V1 is a predetermined start determination threshold value (for example, 6V). When it is below or when the cranking voltage V2 is below a predetermined cranking determination threshold value (for example, 8V), it is determined that the battery is deteriorated.

JP, 2011-130620, A

  However, in the conventional deterioration determination method, the deterioration of the battery progresses too much when the starting voltage V1 becomes equal to or lower than the starting judgment threshold value or the cranking voltage V2 becomes equal to or lower than the cranking judgment threshold value. Moreover, there are cases where recovery is impossible due to activation of the battery. If the start determination threshold value and the cranking determination threshold value are increased, it is possible to determine the deterioration of the battery at an early stage, but the opportunity to execute the charging control, the IDS control, etc. is deprived, and the fuel efficiency of the vehicle is deteriorated.

  An object of the present invention is to provide a vehicle control device that can extend the life of a battery while ensuring the opportunity of executing charging control, IDS control, and the like.

  In order to achieve the above-mentioned object, a vehicle control device according to the present invention includes an engine, a starter for cranking the engine, a generator that generates power by rotation of the engine, and a battery that is charged by power generated by the generator. A control device used in an installed vehicle, wherein a voltage acquisition unit that acquires a minimum value of the terminal voltage of the battery and a minimum value of the terminal voltage acquired by the voltage acquisition unit are in a predetermined period after the starter is started. Determination means for determining whether or not it is less than or equal to 1 determination threshold and whether or not the minimum value of the terminal voltage is less than or equal to a second determination threshold smaller than the first determination threshold; and a result of determination by the determination means. If the minimum value of the terminal voltage is less than or equal to the first determination threshold value and greater than the second determination threshold value, the execution of control that causes the deterioration of the battery is limited, and If the minimum value of equal to or less than the second determination threshold value, and a control limiting means to enhance the restriction of the execution of the control.

  According to this configuration, the minimum value of the terminal voltage (battery voltage) of the battery is acquired during the predetermined period after the starter is started. Then, it is determined whether the minimum value of the battery voltage is equal to or less than the first determination threshold value or the second determination threshold value that is smaller than the first determination threshold value.

  When the minimum value of the battery voltage is less than or equal to the first determination threshold value and greater than the second determination threshold value, execution of the control that causes the deterioration of the battery is limited. When the minimum value of the battery voltage is less than or equal to the second determination threshold value, the execution of the control that causes the deterioration of the battery to proceed is further strongly restricted. As a result, it is possible to gradually limit the execution of the control that causes the deterioration of the battery, and thus it is possible to extend the life of the battery while securing an opportunity to execute the control.

  The predetermined period in which the minimum value of the battery voltage is acquired may be a single period or multiple periods. For example, the minimum value of the battery voltage is acquired during both the period from the start of the starter until the first time elapses and the period after the end of the period from the start of the starter until the second time elapses. May be done.

  Charge control (charging / discharging control) that suppresses power generation by a generator to improve fuel consumption, and IDS control that suppresses engine idling to improve fuel consumption are controls that cause deterioration of the battery to progress. (Idling stop control), push charging in which the battery is further charged after charging the battery without excess or deficiency. The control limited by the control limiting means may be one of these controls or a plurality of them.

  According to the present invention, it is possible to stepwise limit the execution of control that causes the deterioration of the battery, such as charging control and IDS control, so that the life of the battery is ensured while ensuring the opportunity to execute the control. Can be extended.

FIG. 3 is a block diagram showing an electrical configuration of a main part of a vehicle equipped with an ECU according to an embodiment of the present invention. It is a figure which shows the time change of the battery voltage at the time of engine start. It is a flow chart which shows a flow of voltage acquisition processing. It is a flow chart which shows a flow of the 1st deterioration judging processing. It is a flow chart which shows a flow of the 2nd deterioration judging processing. 9 is a table showing a correspondence relationship between a battery deterioration state and permission / prohibition of various controls.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Electrical configuration>
FIG. 1 is a block diagram showing an electrical configuration of a main part of a vehicle 1 equipped with an ECU 11 according to an embodiment of the present invention.

  The vehicle 1 is an automobile driven by the engine 2. Along with the engine 2, a starter 3 for cranking the engine 2 and an alternator 4 for generating power by the rotation of the engine 2 are provided. A battery 5 is mounted on the vehicle 1. The battery 5 is, for example, a lead battery having a nominal voltage of 12V.

  A voltage is applied to the starter 3 from the battery 5 via the power supply line 6 when the engine 2 is started. A flywheel is held on the crankshaft of the engine 2, and when a voltage is applied to the starter 3, the plunger of the starter 3 moves and the starter gear of the starter 3 meshes with the flywheel of the engine 2. Further, the relay built in the starter 3 is turned on, the current supplied from the battery 5 to the starter 3 is increased, a large torque is input from the starter 3 to the engine 2, and the engine 2 is cranked by the torque. It The engine 2 is started by sparking the spark plug of the engine 2 while the engine 2 is cranked.

  Further, the voltage of the battery 5 is applied to an electric load 7 such as a wiper motor, a headlight, an air conditioner and an audio device mounted on the vehicle 1.

  The alternator 4 includes a rotor, a stator and an IC regulator. The rotor rotates as the crankshaft of the engine 2 rotates. The rotor is provided with a field coil (rotor coil). By supplying a field current (excitation current) from the IC regulator to the field coil of the rotating rotor, a three-phase alternating current due to electromagnetic induction flows through the stator coil provided in the stator. The three-phase alternating current is rectified by a rectifier into a direct voltage. The alternator 4 outputs DC electric power as generated electric power, and the generated electric power is supplied to the battery 5 via the power supply line 6, whereby the battery 5 is charged.

  Further, the vehicle 1 is provided with, for example, a plurality of ECUs (Electronic Control Units). The ECU 11 described below is included in the plurality of ECUs. Each ECU has the same hardware configuration, and is connected so as to be capable of bidirectional communication according to a CAN (Controller Area Network) communication protocol.

  The ECU 11 includes a CPU 12 and a memory 13 (ROM, RAM, etc.). A current sensor 14 provided in association with the negative terminal of the battery 5 is connected to the ECU 11. The current sensor 14 employs a sensor that can detect a charge current flowing through the negative terminal of the battery 5 and a discharge current flowing through the negative terminal of the battery 5 separately. Further, the terminal voltage (battery voltage) of the battery 5 is input to the ECU 11. Further, although not shown, the ECU 11 outputs an accelerator sensor, which outputs a detection signal corresponding to an operation amount of an accelerator pedal, and an engine speed sensor which outputs a pulse signal synchronized with the rotation of the crankshaft of the engine 2 as a detection signal. Various sensors such as a throttle opening sensor that outputs a detection signal corresponding to the opening of the electronic throttle valve of the engine 2 (throttle opening) are connected.

  The ECU 11 uses an electronic throttle valve of the engine 2 for starting, stopping, and adjusting the output of the engine 2 based on information acquired from detection signals of various sensors and / or various information input from other ECUs. It controls the injector and the spark plug, the starter 3 and the like. Further, the ECU 11 calculates a battery remaining amount, which is a remaining charge amount of the battery 5, and controls power generation by the alternator 4 based on the battery remaining amount. Further, when the battery remaining amount is calculated by the ECU 11, the calculated battery remaining amount is updated and stored in the memory 13.

<Change in battery voltage>
FIG. 2 is a diagram showing a time change of the battery voltage at the time of starting the engine 2.

  When the engine 2 is started, a starter signal for turning on a starter relay provided on the power feeding path of the starter 3 is output (from OFF to ON) from the ECU 11, and a voltage is applied from the battery 5 to the starter 3. When the plunger of the starter 3 moves and the relay built in the starter 3 is turned on, the current supplied from the battery 5 to the starter 3 increases and the battery voltage drops sharply. After that, the battery voltage starts to rise and repeatedly fluctuates up and down while the engine 2 is cranked by the torque from the starter 3.

  Therefore, the minimum value of the battery voltage VB in the first time T1-T2 from the output of the starter signal occurs due to the start of the starter 3. Further, the minimum value of the battery voltage VB in the period T2-T3 after the elapse of the first time T1-T2 and before the elapse of the second time T1-T3 from the output of the starter signal is determined by the cranking of the engine 2. Caused by.

<Voltage acquisition process>
FIG. 3 is a flowchart showing the flow of the voltage acquisition process.

  When the engine 2 is started, the ECU 11 executes the voltage acquisition process at a constant cycle (for example, 1 msec).

  In the voltage acquisition process, when the starter signal is switched from off to on (YES in step S1), it is determined whether or not the elapsed time from the switch from off to on is within the first time T1-T2 ( Step S2).

  When it is within the first time T1-T2 (YES in step S2), the battery voltage VB is acquired. Then, the obtained battery voltage VB is compared with the starting voltage VBSTA stored in the memory 13, and if the battery voltage VB is smaller than the starting voltage VBSTA, the starting voltage VBSTA is rewritten with the battery voltage VB (step S3). The initial value of the starting voltage VBSTA is 12V, for example.

  The voltage acquisition process is repeatedly executed until the first time T1-T2 elapses, thereby obtaining the minimum value of the battery voltage VB at the first time T1-T2, and the minimum value is stored in the memory 13 as the starting voltage VBSTA. Finally remembered.

  When the elapsed time from the switching of the starter signal from OFF to ON exceeds the first time T1-T2 (NO in step S2), whether or not the elapsed time from the switching is within the second time T1-T3. It is determined (step S4).

  When it is within the second time T1-T3 (YES in step S4), the battery voltage VB is acquired. Then, the obtained battery voltage VB and the cranking voltage VBCRK stored in the memory 13 are compared, and when the battery voltage VB is smaller than the cranking voltage VBCRK, the cranking voltage VBCRK is rewritten with the battery voltage VB. (Step S3). The initial value of the cranking voltage VBCRK is, for example, 12V.

  The voltage acquisition process is repeatedly executed until the second time T1 to T3 elapses, so that after the first time T1 to T2 elapses and until the second time T1 to T3 elapses after the starter signal is switched. The minimum value of the battery voltage VB in the period T2-T3 is obtained, and the minimum value is finally stored in the memory 13 as the cranking voltage VBCRK.

<First deterioration determination process>
FIG. 4 is a flowchart showing the flow of the first deterioration determination process.

  After obtaining the starting voltage VBSTA, the ECU 11 executes the first deterioration determination process.

  In the first deterioration determination process, first, it is determined whether or not the starting voltage VBSTA is equal to or lower than a predetermined first determination threshold V11 (step S11).

  If the starting voltage VBSTA is equal to or lower than the first determination threshold V11 (YES in step S11), then it is determined whether the starting voltage VBSTA is equal to or lower than the second determination threshold V12 which is lower than the first determination threshold V11. (Step S12).

  When the starting voltage VBSTA is less than or equal to the first determination threshold V11 and greater than the second determination threshold V12 (NO in step S12), 1 is set in the first intermediate deterioration determination flag provided in the memory 13 (step S13). ), The first deterioration determination process ends.

  When the starting voltage VBSTA is equal to or lower than the second determination threshold V12 (YES in step S12), the second intermediate deterioration determination flag provided in the memory is set to 1 (step S14), and the first deterioration determination process is ended. It

  The first intermediate deterioration determination flag and the second intermediate deterioration determination flag are reset to 0 when the engine 2 is stopped. When the starting voltage VBSTA is larger than the first determination threshold value V11 (NO in step S11), the first deterioration determination process ends with the first intermediate deterioration determination flag and the second intermediate deterioration determination flag remaining at 0.

<Second deterioration determination process>
FIG. 5 is a flowchart showing the flow of the second deterioration determination process.

  After obtaining the cranking voltage VBCRK, the ECU 11 executes the second deterioration determination process.

  In the second deterioration determination process, first, it is determined whether or not the cranking voltage VBCRK is equal to or lower than a predetermined first determination threshold V21 (step S21).

  When the cranking voltage VBCRK is equal to or lower than the first determination threshold V21 (YES in step S21), it is then determined whether the cranking voltage VBCRK is equal to or lower than the second determination threshold V22 which is lower than the first determination threshold V21. (Step S22).

  When the cranking voltage VBCRK is equal to or lower than the first determination threshold V21 and larger than the second determination threshold V22 (NO in step S22), 1 is set to the first intermediate deterioration determination flag provided in the memory 13 (step S22). S23), the second deterioration determination process is ended.

  When the cranking voltage VBCRK is equal to or lower than the second determination threshold V22 (YES in step S22), 1 is set to the second intermediate deterioration determination flag provided in the memory (step S24), and the second deterioration determination process ends. To be done.

  When the cranking voltage VBCRK is higher than the first determination threshold value V21 (NO in step S21), the second degradation determination process ends with the first intermediate degradation determination flag and the second intermediate degradation determination flag remaining at 0.

<Control according to battery deterioration state>
FIG. 6 is a table showing a correspondence relationship between the deterioration state of the battery 5 and permission / prohibition of various controls.

  In the vehicle 1, the ECU 11 can execute IDS control (idling stop control), charge control (charge / discharge control), and push-in charging.

  The IDS control is a technique for improving fuel efficiency by suppressing idling of the engine 2. In the IDS control, when the brake pedal is operated (stepped on) while the vehicle 1 is traveling, it is determined whether or not a predetermined IDS start condition is satisfied. The IDS start condition is, for example, a condition that the vehicle speed is equal to or lower than a predetermined idling stop execution vehicle speed (for example, 10 km / h), and that the brake pedal is operated for a certain time or longer. While the brake pedal is being operated, whether or not the IDS start condition is satisfied is determined in a constant cycle. Then, when the IDS start condition is satisfied, the engine 2 is stopped (idling stop). After the start of idling stop, it is determined in a constant cycle whether or not a predetermined IDS return condition is satisfied. The IDS return condition is, for example, a condition in which the operation of the brake pedal is released (the driver's foot is released from the brake pedal) during idling stop. When the IDS return condition is satisfied, the starter 3 is activated and the engine 2 is restarted.

  The charge control is a technique for improving fuel efficiency by suppressing power generation by the alternator 4. In the charge control, SOC (State Of Charge), which is the ratio of the battery remaining amount stored in the memory 13 to the charge capacity (full charge amount) of the battery 5, is calculated. Then, when the SOC is equal to or higher than the upper limit value of the charge control range, the power generation by the alternator 4 is stopped. If the SOC is greater than or equal to the lower limit value and less than the upper limit value of the charge control range, it is determined whether the vehicle 1 is decelerating, and the power generation of the alternator 4 is controlled according to the determination result. That is, when the vehicle 1 is not decelerating, power generation by the alternator 4 is stopped, and when the vehicle 1 is decelerating, power generation by the alternator 4 is performed.

  Push-in charging is a technique for extending the life of the battery 5. Push-in charging is executed after the battery 5 is charged to a fully charged state. In order to determine whether or not the battery 5 has been charged to the fully charged state, the current value of the charging current of the battery 5 is acquired based on the detection signal of the current sensor 14 during power generation by the alternator 4. Then, when the current value of the charging current drops to a predetermined full charge determination threshold value, it is determined that the battery 5 is in a fully charged state. Then, when the battery 5 is charged to the fully charged state, the push-in charging is executed, and the charge of the battery 5 with a constant charge current is continued until a predetermined push-in time elapses.

  State in which the battery 5 is not deteriorated (no deterioration), that is, a state in which both the first intermediate deterioration determination flag and the second intermediate deterioration determination flag are reset to 0, IDS control, charge control, and forced charging are all performed. Is allowed. The full charge determination threshold value used to determine the full charge state is set to, for example, 5A.

  When the first intermediate deterioration determination flag is set to 1 (deterioration 1), IDS control and push-in charging are permitted. The charge control is prohibited from being executed until the fully charged state of the battery 5 is determined, and is allowed to be executed after the fully charged state is determined. The full charge determination threshold value used to determine the full charge state is set to, for example, 5A.

  In the state where the second intermediate deterioration determination flag is set to 1 (deterioration 2), execution of IDS control is permitted, but execution of charge control and forced charging is prohibited.

  In addition, since the battery 5 has deteriorated and the battery voltage has dropped, for example, sufficient operating power cannot be supplied from the battery 5 to the starter 3 when the engine 2 is started, so that the engine 2 is stable and prompt. If it is in a state where the engine cannot be started (failure to start), execution of all of the IDS control, the charging control and the push charging is prohibited.

<Effect>
As described above, the starting voltage VBSTA, which is the minimum value of the battery voltage VB in the period T1-T2, during the period T1-T2 from the switching of the starter signal from ON to ON until the first time T1-T2 elapses. To be acquired. Then, it is respectively determined whether or not the starting voltage VBSTA is equal to or lower than the first determination threshold value V11 or the second determination threshold value V12 smaller than the first determination threshold value V11.

  When the starting voltage VBSTA is equal to or lower than the first determination threshold value V11 and is higher than the second determination threshold value V12 (deterioration 1), execution of charging control, which is one of the controls that cause the deterioration of the battery 5 to proceed, is executed. Limited. When the starting voltage VBSTA is equal to or lower than the second determination threshold V12 (deterioration 2), execution of charge control and forced charging is prohibited.

  Further, after the first time T1-T2 has elapsed, during the period T2-T3 from the switching of the starter signal from OFF to ON until the second time T1-T3 elapses, the battery voltage in the period T2-T3. The cranking voltage VBCRK, which is the minimum value of VB, is acquired. Then, it is determined whether or not the cranking voltage VBCRK is equal to or lower than the first determination threshold V21, or whether or not the cranking voltage VBCRK is a second determination threshold V22 smaller than the first determination threshold V21.

  If the cranking voltage VBCRK is equal to or lower than the first determination threshold V21 and is higher than the second determination threshold V22 (deterioration 1), execution of the charging control is limited. When the cranking voltage VBCRK is equal to or lower than the second determination threshold value V22 (deterioration 2), execution of charge control and forced charge is prohibited. As a result, the execution of the charge control can be restricted stepwise, so that the life of the battery 5 can be extended while ensuring the opportunity of executing the charge control.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be implemented in other forms.

  For example, although the full charge determination threshold value used to determine the full charge state is set to 5A, the full charge determination threshold value may be variably set according to the battery liquid temperature (temperature of the battery 5). That is, since the performance of the battery 5 increases as the battery fluid temperature increases, the full charge determination threshold may be set to a large value. The full charge determination threshold may be variably set according to the deterioration state of the battery. For example, when the battery 5 is not deteriorated, the full charge determination threshold is set to a relatively large value, and when the first intermediate deterioration determination flag is set to 1 (deterioration 1), the full charge determination threshold is set. May be set to a relatively small value.

  The pushing time may be constant, or may be variably set according to the battery fluid temperature. That is, as the battery liquid temperature is higher, the performance of the battery 5 is higher, and thus the pushing time may be set to a longer time. Further, the pushing time may be variably set according to the deterioration state of the battery. For example, when the battery 5 is not deteriorated, the pushing time is set to a relatively long time, and when the first intermediate deterioration determination flag is set to 1 (deterioration 1), the pushing time is relatively set. It may be set to a short time.

  Further, in the above-described embodiment, the configuration in which the execution of the charging control and the push-in charging is limited according to the state of deterioration of the battery 5 has been taken up. However, the control whose execution is limited according to the state of deterioration of the battery 5 is not limited to the charge control and the push charge, and may be either one of them or the IDS control. For example, in a state where the first intermediate deterioration determination flag is set to 1 (deterioration 1), execution of IDS control is permitted, and in a state where the second intermediate deterioration determination flag is set to 1 (deterioration 2), Execution of IDS control may be prohibited. Further, in a state where the first intermediate deterioration determination flag is set to 1 (deterioration 1), execution of IDS control is permitted, and in a state where the second intermediate deterioration determination flag is set to 1 (deterioration 2), The IDS start condition in the IDS control may be made stricter than in the state where the first intermediate deterioration determination flag is set to 1 (deterioration 1).

  In the IDS control, an ECU other than the ECU 11, for example, an IDSECU for the IDS control may determine whether the IDS start condition is satisfied. In this case, an engine stop request is transmitted from the IDSECU to the ECU 11 in response to the satisfaction of the IDS start condition, and the ECU 11 stops the engine 2 in response to the engine stop request. Further, the IDSECU determines whether or not the IDS restoration condition is satisfied. When the IDS return condition is satisfied, the IDSECU sends an engine restart request to the ECU 11, and the ECU 11 restarts the engine 2 in response to the engine restart request.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

1 vehicle 2 engine 3 starter 4 alternator (generator)
5 Battery 11 ECU (vehicle control device, voltage acquisition means, determination means, control restriction means)

Claims (1)

A control device used in a vehicle equipped with an engine, a starter for cranking the engine, a generator that generates power by rotation of the engine, and a battery that is charged with power generated by the generator,
In a predetermined period after starting the starter, voltage acquisition means for acquiring a minimum value of the terminal voltage of the battery,
Whether the minimum value of the terminal voltage acquired by the voltage acquisition unit is less than or equal to a first determination threshold value and whether the minimum value of the terminal voltage is less than or equal to a second determination threshold value smaller than the first determination threshold value Determination means for determining whether or not,
As a result of the judgment by the judgment means, when the minimum value of the terminal voltage is equal to or lower than the first judgment threshold value and larger than the second judgment threshold value, the execution of the control that causes the deterioration of the battery is restricted, and the terminal voltage is reduced. If the minimum value of equal to or less than the second determination threshold value, look including a control limiting means to enhance the restriction of the execution of the control,
The control that causes the deterioration of the battery to proceed includes push charging in which the battery is continuously charged until a predetermined push time elapses after the battery is charged to a fully charged state,
The control device for a vehicle , wherein the pushing time is variably set according to a deterioration state of the battery .

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