JP2019056311A - Engine stop control device and stop control method - Google Patents

Abstract

To avoid idling stop in a state where a battery is disconnected. An engine stop control device includes an in-vehicle battery, an alternator that is connected to the in-vehicle battery and generates power as the engine operates, and a starter that starts the engine using electric power supplied from the in-vehicle battery. In a vehicle driven by an engine, when the vehicle speed of the vehicle is lower than a predetermined value, a stop control unit that stops the engine when receiving stop permission information, a current flowing through the in-vehicle battery, and an in-vehicle battery Based on the detection unit that detects the voltage, and the current detection value and the voltage detection value detected by the detection unit, the presence or absence of disconnection in the in-vehicle battery is determined. And a stop permission / rejection determination unit for transmitting to the unit. [Selection] Figure 3

Description

  The present invention relates to a technique for controlling automatic stop of an engine.

  2. Description of the Related Art Generally, a vehicle is known that is equipped with an alternator that generates electric power as the engine is operated, a starter that starts the engine, and an in-vehicle battery that is connected to the alternator and the starter. An idling stop that automatically stops the engine is also known.

  In Patent Document 1, in such a vehicle, the state of charge of the in-vehicle battery (state of charge is abbreviated as SOC) is estimated, and whether or not the remaining capacity of the in-vehicle battery remains sufficiently based on the estimation result. A technique for judging and allowing idling stop if it remains is disclosed. Non-Patent Document 1 discloses the relationship between the SOC and the battery open circuit voltage (also referred to as battery open circuit voltage (abbreviated as open circuit voltage or OCV)).

Japanese Patent No. 5335594

Noriyoshi Iwane, “Lead battery state detection sensor-Prediction of battery open circuit voltage by fifth exponential function-”, Furukawa Electric Time Report No. 120, [online], September 2007, Furukawa Electric Co., Ltd. [Heisei Search on August 17, 2017], Internet (URL: https://www.furukawa.co.jp/jiho/fj120/fj120_12.pdf)

  However, even when there is sufficient remaining capacity of the in-vehicle battery, the in-vehicle battery is disconnected (for example, the electrode plate in the in-vehicle battery is damaged or the electrode plate and the terminal are disconnected). If idling stop is permitted in the state where the vehicle is running, etc., power cannot be supplied from the vehicle battery or the alternator to the starter, and the engine cannot be restarted and the vehicle cannot be restarted.

  This causes the vehicle to become stuck and eventually leads to traffic jams and traffic accidents, so there is room for improvement in terms of technology that allows idling stop.

  Therefore, an object of the present invention is to provide an engine stop control device and a stop control method for avoiding a failure of engine restart after idling stop.

  In order to solve the above problems, an onboard battery, an alternator that is connected to the onboard battery and generates power as the engine operates, and a starter that starts the engine using electric power supplied from the onboard battery are mounted. In a vehicle driven by the engine, a stop control device that controls the automatic stop of the engine stops the engine when stop permission information is received when the vehicle speed of the vehicle is lower than a predetermined value. A stop control unit; a detection unit that detects a current flowing through the in-vehicle battery and a voltage applied to the in-vehicle battery; and a presence or absence of disconnection in the in-vehicle battery based on a current detection value and a voltage detection value detected by the detection unit And determining whether or not to stop transmitting the stop permission information to the stop control unit when it is determined that there is no disconnection. Provided with a door.

  In the present invention, since idling stop is prevented in a state where the in-vehicle battery is disconnected, failure of engine start after idling stop is avoided.

It is a figure which shows the whole structure of the vehicle to which the stop control apparatus was applied. It is a flowchart at the time of performing an automatic stop process after an engine starting process. It is a flowchart at the time of judging the presence or absence of the disconnection in a vehicle-mounted battery.

{Embodiment}
FIG. 1 is a diagram illustrating a configuration of the stop control device 1. The stop control device 1 is mounted on a vehicle (not shown) together with the engine 10.

  An output shaft (crankshaft) 12 of the engine 10 is mechanically connected to drive wheels (not shown) to drive the vehicle. The alternator 22 is a generator that generates power as the engine 10 is operated, and is mounted on a vehicle. Specifically, the rotor of the alternator 22 is mechanically connected to the crankshaft 12 of the engine 10, and the alternator 22 generates electricity when the rotor is rotated by the rotational force of the crankshaft 12. Therefore, the alternator 22 may generate power by coasting the vehicle in addition to the operation of the engine 10. In FIG. 1, these mechanical connections are schematically represented by a one-dot chain line.

  The regulator 24 is a control circuit that controls the output of the alternator 22 and functions as a voltage adjustment unit that adjusts the output voltage of the alternator 22. Here, the alternator 22 and the regulator 24 are described as separate configurations, but a regulator capable of adjusting the output voltage may be provided inside the alternator 22 and the regulator 24 may be omitted.

  A vehicle-mounted battery 30 is connected to the battery terminal TB of the regulator 24. For example, a lead storage battery is used for the in-vehicle battery 30. Each of the plurality of electric loads 44 is connected to the in-vehicle battery 30 in parallel with each other via each of the plurality of switches 42. The plurality of electric loads 44 include a speedometer that measures the vehicle speed of the traveling vehicle.

  Furthermore, a starter 40 is connected to the in-vehicle battery 30 as an electric load. The starter 40 is mechanically connected to the crankshaft 12 and applies an initial rotation to the engine 10 to start the engine 10. This mechanical connection is also schematically represented by a chain line in FIG.

  The power supply line J1 between the battery terminal TB and the in-vehicle battery 30 and the ignition terminal TIG of the regulator 24 are connected via an ignition switch 46.

  An ECU (Electronic Control Unit) 50 as one of the electric loads of the in-vehicle battery 30 includes a storage device and is configured mainly with a microcomputer. This storage device always holds the memory regardless of the state of the main power supply of the ECU 50 (here, the ignition switch 46). Specifically, the storage device is a backup RAM in which a power supply state is always maintained, a non-volatile memory such as an EEPROM that always stores data regardless of whether power is supplied, or the like.

  The current sensor 52 is provided on the power supply line J1, detects a current discharged from the in-vehicle battery 30 and a current charged into the in-vehicle battery 30, and outputs a current detection value to the ECU 50. The voltage sensor 56 detects a voltage applied to the in-vehicle battery 30 and outputs a voltage detection value to the ECU 50. Thus, the current sensor 52 and the voltage sensor 56 function as the detection unit 5 that detects the current flowing through the in-vehicle battery 30 and the voltage applied to the in-vehicle battery 30.

  The ECU 50 controls the engine 10, the alternator 22, and the regulator 24 with respect to the components shown in FIG. 1. In particular, the ECU 50 controls the output voltage of the alternator 22 based on the current detection value output from the current sensor 52 and the voltage detection value output from the voltage sensor 56. More specifically, the ECU 50 outputs a command value (command voltage) of the output voltage to the command terminal TR of the regulator 24. As a result, the regulator 24 adjusts the output voltage of the alternator 22 to the command voltage.

  Further, the ECU 50 takes in a power generation state signal indicating the power generation capability of the alternator 22 and the regulator 24 via the monitor terminal TF of the regulator 24. Here, the power generation capacity is a value quantified by the ON / OFF time ratio of the switching element in the regulator 24 (specifically, the ratio of the ON time to the ON / OFF cycle: Duty).

  The control of the output voltage is performed so as to reduce as much as possible the increase in fuel consumption of the engine 10 due to the power generation of the alternator 22 while keeping the charge state of the in-vehicle battery 30 within an allowable range. Here, the state of charge of the in-vehicle battery 30 is a physical quantity obtained by quantifying the discharge capacity of the in-vehicle battery 30 (more specifically, the ratio of the current charge amount to the full charge of the in-vehicle battery 30). As shown in Non-Patent Document 1, it is known that the battery open voltage, which is the voltage when the terminal of the in-vehicle battery 30 is open, depends on the state of charge of the in-vehicle battery 30. Further, the relationship between the battery open voltage and the state of charge of the in-vehicle battery 30 is stored in the storage device of the ECU 50.

  The ECU 50 also includes a start control unit 57, a stop control unit 58, and a stop permission / inhibition determination unit 59.

  The start control unit 57 is a functional unit that controls the start process of the engine 10 and supplies the starter 40 with electric power from the in-vehicle battery 30 to start the engine 10. Here, the start process is a process in which the start control unit 57 functions to start the engine 10 when the driver of the vehicle turns on the ignition switch 46.

  The stop control unit 58 and the stop permission / rejection determination unit 59 are functional units that perform automatic stop processing of the engine 10. Here, the automatic stop process is a process of automatically stopping the engine 10 when the vehicle speed of the traveling vehicle decreases, and indicates an idling stop.

  The stop control unit 58 stops the engine 10 when the vehicle speed of the vehicle is lower than a predetermined value and when all stop permission information described later is received.

  When the stop permission / inhibition determination unit 59 determines the presence or absence of disconnection in the in-vehicle battery 30 based on the current detection value detected by the current sensor 52 and the voltage detection value detected by the voltage sensor 56, and determines that there is no disconnection The stop permission information 60 is transmitted to the stop control unit 58.

  Usually, during idling stop, since the electric power to the various electric loads 44 must be supplied from the in-vehicle battery 30, the SOC of the in-vehicle battery 30 decreases. In the next start-up process, power must be supplied from the in-vehicle battery 30 to the starter 40. Therefore, it is necessary to permit the automatic stop process in a state where the in-vehicle battery 30 is charged with the amount of SOC reduction during idling and the amount of power supplied to the starter 40 at the next start.

  Therefore, as information adopted as a basis for permitting the automatic stop process, in addition to the stop permission information 60 (information transmitted when there is no disconnection in the in-vehicle battery 30), other stop permission information (for example, , Information transmitted when the SOC is sufficiently secured). Whether or not the SOC is sufficiently secured is determined, for example, as shown in Patent Document 1, whether the current detection value is smaller than the reference value or whether the voltage detection value is larger than the reference value. based on.

  The stop control device 1 is configured to include a start control unit 57, a stop control unit 58, a stop permission / rejection determination unit 59, and a detection unit 5, and controls the start and stop of the engine 10. Details of the start process and the automatic stop process performed by the stop control device 1 will be described later with reference to FIGS.

  FIG. 2 is a flowchart when an automatic stop process is performed after the start process of the engine 10. Hereinafter, the flow of processing when performing automatic stop processing after the start processing of the engine 10 will be described with reference to FIG.

  First, as shown in step ST <b> 1 of FIG. 2, when the driver of the vehicle turns on the ignition switch 46, the start control unit 57 starts the engine 10. Thereafter, the stop control device 1 determines whether or not the vehicle speed has decreased below a predetermined value in step ST2. The vehicle speed information is obtained from the above-mentioned vehicle speed meter. Immediately after the vehicle starts to travel, the speed increases without decreasing. Therefore, even if the vehicle speed is lower than the predetermined value, the determination result is No, and the determination in step ST2 is continued. Similarly, even when the vehicle speed is equal to or higher than the predetermined value, the determination result in step ST2 is No, and the traveling state is maintained.

  When the vehicle speed falls below the predetermined value, the determination result in step ST2 is Yes, and the process proceeds to step ST3. In step ST3, the stop control device 1 determines whether all stop permission information necessary for permitting the automatic stop process has been prepared. All stop permission information in the stop control unit 58 (for example, two pieces of stop permission information: information transmitted when there is no disconnection in the in-vehicle battery 30 and information transmitted when the SOC is sufficiently secured) 2 is Yes, the determination result in Step ST3 in FIG. 2 is Yes, and the process proceeds to Step ST4. In Step ST4, an automatic stop process is performed by the stop control unit 58 (stop process). On the other hand, if at least one piece of stop permission information is missing, the process proceeds to No in step ST3 of FIG. 2 and the automatic stop process is not performed.

  Thus, by using the stop permission information 60, it is possible to prevent idling from being stopped in a state where the in-vehicle battery is disconnected, and to avoid failure of engine restart after idling is stopped. Further, by using the stop permission information that the SOC is sufficiently secured, it is possible to prevent idling stop in a state where the SOC is insufficient, and to avoid failure of engine restart after idling stop.

  FIG. 3 is a flowchart for determining whether or not the in-vehicle battery 30 is disconnected. Each step shown in FIG. 3 is executed, for example, at a timing when the determination result in step ST2 shown in FIG. 2 shifts from No to Yes. Below, the flow of processing when determining the presence or absence of disconnection in the in-vehicle battery 30 will be described with reference to FIG.

  In the present specification, the disconnection in the in-vehicle battery 30 refers to the disconnection occurring on the in-vehicle battery 30 side when viewed from two connection points of the electric wire extending from the in-vehicle battery 30 and the electric wire extending from the voltage sensor 56. Point to. Specifically, when there is a disconnection in the in-vehicle battery 30, for example, when the electrode plate in the in-vehicle battery is damaged, when the electrode plate in the in-vehicle battery and the terminal are disconnected, the in-vehicle battery 30. And the case where a connection failure between the external electric wire and the electric wire extending from the in-vehicle battery 30 is cut off in the section between the two connection points.

  When the determination result of step ST2 of FIG. 2 shifts from No to Yes, step ST10 of FIG. 3 is executed. In step ST10, the current sensor 52 detects a current flowing through the in-vehicle battery 30 (denoted as “battery current” in FIG. 3), and gives the detected first current detection value to the stop permission / inhibition determination unit 59 (detection step).

  Thereafter, the process proceeds to step ST11, and the stop permission / rejection determination unit 59 refers to the first current detection value, and determines the magnitude relationship between the absolute value of the first current detection value and the first non-negative predetermined value. In comparison, it is determined whether or not the first current detection value can be regarded as 0 A (ampere, the same applies hereinafter). To do. The predetermined value is set to a value that is sufficiently smaller than the current that normally flows through the in-vehicle battery 30, such as 0.1 mA (milliampere; the same applies hereinafter).

  As a result of the comparison, when the absolute value of the first current detection value exceeds the first non-negative predetermined value, the determination result in step ST11 of FIG. 3 is No, and the process proceeds to step ST19. In step ST19, as shown in FIG. 3, the stop permission / rejection determination unit 59 determines that there is no disconnection in the in-vehicle battery 30. At this time, the stop permission / inhibition determination unit 59 gives the stop permission information 60 to the stop control unit 58 (stop permission / inhibition determination step).

  On the other hand, if the absolute value of the first current detection value is equal to or smaller than the predetermined value as a result of the comparison, the determination result in step ST11 of FIG. 3 is Yes, and the process proceeds to step ST12. As described above, whether or not the first current detection value can be regarded as 0 A is determined by comparing the magnitude relationship between the absolute value of the first current detection value and the first non-negative predetermined value. When the first current detection value can be regarded as 0 A, the in-vehicle battery 30 is disconnected, and the in-vehicle battery 30 is not disconnected and the electric power output from the alternator 22 is supplied to each electric load 44. It is assumed that the vehicle-mounted battery 30 is not charged or discharged. While the automatic stop process cannot be permitted in the former case, the automatic stop process can be permitted in the latter case. Therefore, the cases of these two cases are divided in steps ST12 to ST16 described later.

  As shown in step ST12 of FIG. 3, the stop permission / rejection determination unit 59 controls the regulator 24 to decrease the output voltage of the alternator 22 (voltage adjustment step). In addition, as shown in step ST13 of FIG. 3, the voltage sensor 56 detects the voltage applied to the in-vehicle battery 30, and provides the detected voltage detection value to the stop permission / rejection determination unit 59. Then, as shown in step ST14 of FIG. 3, the stop permission / rejection determination unit 59 refers to the voltage detection value and compares the magnitude relationship between the voltage detection value and the battery open voltage. The battery open voltage is, for example, 12.8 V (volt, the same applies hereinafter), and is specified based on information stored in the storage device of the ECU 50 (for example, the relationship between the battery open voltage and the charge state of the in-vehicle battery 30). The If the detected voltage value is equal to or higher than the battery open voltage, the determination result in step ST14 is No, the process proceeds to step ST12, and steps ST12 to ST14 are repeated.

  As a result, the output voltage of the alternator 22 is lowered until the voltage detection value becomes smaller than the battery open voltage, the determination result in Step ST14 is Yes, and the process proceeds to Step ST15. Thus, in the latter case (that is, when the electric power output from the alternator 22 is supplied to each electric load 44 and neither the vehicle battery 30 is charged nor discharged), the vehicle battery 30 is discharged. Directional current is expected to flow. On the other hand, in the former case (when disconnection occurs in the in-vehicle battery 30), no current flows through the in-vehicle battery 30. Therefore, by detecting again the current flowing through the in-vehicle battery 30, it can be determined that there is no disconnection if the current in the discharge direction flows through the in-vehicle battery 30, and that there is disconnection when no current flows through the in-vehicle battery 30.

  As shown in step ST15 of FIG. 3, the current sensor 52 detects the current flowing through the in-vehicle battery 30 in a state where the output voltage of the alternator 22 is lowered, and the detected second current detection value is determined as a stop permission / inhibition determination unit. 59 (detection step). The stop permission / rejection determination unit 59 refers to the second current detection value, compares the magnitude relationship between the absolute value of the second current detection value and the second non-negative predetermined value, and determines that the second current detection value is It is determined whether or not it can be regarded as 0A. The second non-negative predetermined value is set to a value sufficiently smaller than the current normally flowing through the in-vehicle battery 30, such as 0.1 mA, for example, as in step ST11 of FIG.

  As a result of the comparison, when the absolute value of the second current detection value exceeds the second non-negative predetermined value, the determination result of step ST16 in FIG. 3 is No, and the process proceeds to step ST20. In step ST20, as shown in FIG. 3, the stop permission / inhibition determination unit 59 determines that there is no disconnection in the in-vehicle battery 30. At this time, the stop permission / inhibition determination unit 59 gives the stop permission information 60 to the stop control unit 58 (stop permission / inhibition determination step). Further, after determining whether or not there is a disconnection, as shown in step ST21 of FIG. 3, the stop permission / inhibition determination unit 59 controls the regulator 24 to restore the output voltage of the alternator 22 to the value before the decrease (voltage adjustment step).

  On the other hand, when the absolute value of the second current detection value is equal to or smaller than the predetermined value as a result of the comparison, the determination result in step ST16 in FIG. 3 is Yes, and the process proceeds to step ST17. In this way, the determination as to whether or not the second current detection value can be regarded as 0 A is made by comparing the magnitude relationship between the absolute value of the second current detection value and the second non-negative predetermined value. When the second current detection value can also be regarded as 0A, since the discharge from the in-vehicle battery 30 does not occur even after the output voltage of the alternator 22 is lowered, there is a high possibility that the in-vehicle battery 30 is disconnected. Therefore, in step ST <b> 17, as shown in FIG. 3, the stop permission / inhibition determination unit 59 determines that there is a disconnection in the in-vehicle battery 30. At this time, the stop permission / rejection determination unit 59 does not give the stop permission information 60 to the stop control unit 58 (stop permission / rejection determination step). Further, after determining whether or not there is a disconnection, as shown in step ST18 of FIG. 3, the stop permission / inhibition determination unit 59 controls the regulator 24 to restore the output voltage of the alternator 22 to the value before the decrease (voltage adjustment step).

  If it is determined that there is a disconnection, the determination result in step ST3 in FIG. 2 is No, and the process proceeds to step ST2, and the automatic stop process is not executed. In this case, a mode in which the vehicle driver is notified of the situation and measures, such as displaying that the in-vehicle battery 30 is disconnected on an in-vehicle monitor (not shown) can be employed.

  As described above, in the technology according to the present embodiment, the idling stop is prevented in a state where the in-vehicle battery is disconnected, so that the engine restart failure after the idling stop can be avoided.

  In the technique of the present embodiment, even if the first current detection value can be regarded as 0 A, the second current in a state where the output voltage of the alternator 22 is lowered without immediately determining that there is a disconnection. The presence or absence of disconnection is determined based on the detected value. Therefore, when the electric power output from the alternator 22 is supplied to each electric load 44 and the vehicle-mounted battery 30 is not charged or discharged, the possibility of erroneously determining that the vehicle-mounted battery 30 is disconnected is reduced. be able to.

  In the technique of the present embodiment, when the regulator 24 decreases the output voltage of the alternator 22, the output voltage is made smaller than the battery open voltage. In general, when the in-vehicle battery 30 is fully charged or when the SOC of the in-vehicle battery 30 is so large that it is close to full charge, it is difficult for the current in the charging direction to flow through the in-vehicle battery 30. In the present embodiment, the output voltage of the alternator 22 is reduced to encourage a current in the discharge direction to flow through the in-vehicle battery 30. Therefore, it is determined whether or not there is a disconnection without being affected by the current hardly flowing in the charge direction. be able to.

  Further, in the technique of the present embodiment, when the output voltage of the alternator 22 is reduced, the regulator 24 sets the output voltage of the alternator 22 to a value before the reduction after the determination of the presence or absence of disconnection by the stop permission / rejection determination unit 59. Restore it. Therefore, it is possible to prevent an adverse effect caused by a decrease in the output voltage of the alternator 22 during the traveling of the vehicle after determining whether or not there is a disconnection.

{Modification}
In the above embodiment, the stop permission information 60 transmitted when there is no disconnection in the in-vehicle battery 30 and the stop permission information transmitted when the SOC is sufficiently secured have been described. Stop permission information may be used.

  Moreover, although the said embodiment reduced the output voltage of the alternator 22 when a 1st electric current detection value is considered to be 0 A, the aspect which detects a 2nd electric current detection value was demonstrated, for example, a 1st electric current When the detected value is regarded as 0A, it may be immediately determined that there is a disconnection.

  Moreover, although the said embodiment demonstrated the aspect which detects a 2nd electric current detection value in the state which lowered | hung the voltage detection value from the battery open voltage in step ST12-ST15, a voltage detection value is made more than a battery open voltage. An aspect in which the second current detection value is detected in a state of being lowered by a predetermined value or more (for example, 0.5 V or more) may be used. In this case, when the output voltage of the alternator 22 is sufficiently reduced, a current in the discharging direction easily flows through the in-vehicle battery 30, and it is easy to determine the presence or absence of disconnection in the subsequent step ST16.

  As described above, the engine stop control device and the stop control method have been described in detail. However, the above description is illustrative in all aspects, and the engine stop control device and the stop control method are limited thereto. It is not a thing. It is understood that countless modifications that are not illustrated can be assumed without departing from the scope of the engine stop control device and the stop control method.

DESCRIPTION OF SYMBOLS 1 Stop control apparatus 5 Detection part 10 Engine 22 Alternator 24 Voltage adjustment part (regulator)
30 onboard battery 40 starter 50 ECU
58 stop control unit 59 stop permission / inhibition judgment unit ST1 to ST4, ST10 to ST21 step

Claims (10)

A vehicle driven by the engine equipped with an in-vehicle battery, an alternator connected to the in-vehicle battery and generating electric power as the engine operates, and a starter that starts the engine using electric power supplied from the in-vehicle battery In the apparatus for controlling the automatic stop of the engine,
A stop control unit that stops the engine when receiving stop permission information when the vehicle speed of the vehicle is lower than a predetermined value;
A detection unit for detecting a current flowing through the in-vehicle battery and a voltage applied to the in-vehicle battery;
Based on the current detection value and the voltage detection value detected by the detection unit, the presence or absence of disconnection in the in-vehicle battery is determined, and when it is determined that there is no disconnection, the stop permission information is transmitted to the stop control unit. An engine stop control device comprising a stop permission / rejection determination unit. The engine stop control device according to claim 1,
The stop permission / rejection determination unit refers to the first current detection value detected by the detection unit, and when the absolute value of the first current detection value exceeds a first non-negative predetermined value, the disconnection is detected. An engine stop control device that determines that there is no. An engine stop control device according to claim 2,
A voltage adjusting unit that adjusts an output voltage of the alternator;
When the absolute value of the first current detection value is less than or equal to the first non-negative predetermined value, the voltage adjustment unit decreases the output voltage, and the stop permission determination unit outputs the output by the voltage adjustment unit. Refer to the second current detection value detected by the detection unit in a state where the voltage is reduced,
The stop permission / rejection determination unit determines that there is a disconnection in the in-vehicle battery when the absolute value of the second current detection value is equal to or less than a second non-negative predetermined value, and determines the second current detection value An engine stop control device that determines that there is no disconnection in the in-vehicle battery when the absolute value exceeds the second non-negative predetermined value. An engine stop control device according to claim 3,
The engine stop control device, wherein when the output voltage is lowered, the voltage adjusting unit lowers the output voltage until it becomes smaller than an open-circuit voltage of the in-vehicle battery. An engine stop control device according to claim 3 or claim 4,
When the output voltage is reduced, the voltage adjustment unit restores the output voltage to a value before the decrease after the determination of the presence or absence of the disconnection by the stop permission determination unit. A vehicle driven by the engine equipped with an in-vehicle battery, an alternator connected to the in-vehicle battery and generating electric power as the engine operates, and a starter that starts the engine using electric power supplied from the in-vehicle battery In the method for controlling the automatic stop of the engine,
A stop step of stopping the engine when receiving the stop permission information when the vehicle speed of the vehicle is lower than a predetermined value;
A detection step of detecting a current flowing through the in-vehicle battery and a voltage applied to the in-vehicle battery;
Based on the detected current value and the detected voltage value detected in the detection step, the presence / absence of disconnection in the in-vehicle battery is determined, and when it is determined that there is no disconnection, the stop permission determination step of outputting the stop permission information; An engine stop control method comprising: The engine stop control method according to claim 6,
In the stop permission / rejection determination step, the first current detection value detected in the detection step is referred to, and when the absolute value of the first current detection value exceeds a first non-negative predetermined value, the disconnection is detected. An engine stop control method that determines that there is no. An engine stop control method according to claim 7,
A voltage adjusting step for adjusting the output voltage of the alternator;
Further comprising
When the absolute value of the first current detection value is less than or equal to the first non-negative predetermined value, the output voltage is reduced in the voltage adjustment step, and the output is performed by the voltage adjustment step in the stop permission determination step. With reference to the second current detection value detected by the detection step in a state where the voltage is reduced,
In the stop permission / rejection determination step, when the absolute value of the second current detection value is equal to or less than a second non-negative predetermined value, it is determined that the disconnection occurs in the in-vehicle battery, and the second current detection value An engine stop control method for determining that there is no disconnection in the in-vehicle battery when an absolute value exceeds the second non-negative predetermined value. An engine stop control method according to claim 8,
An engine stop control method in which, when the voltage adjustment step decreases the output voltage, the output voltage is decreased until it becomes smaller than the open-circuit voltage of the in-vehicle battery. An engine stop control method according to claim 8 or 9, wherein
An engine stop control method in which, when the output voltage is decreased, the voltage adjustment step restores the output voltage to a value before the decrease after the determination of the presence or absence of the disconnection in the stop permission determination step.

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