JP6667960B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a control device used for a vehicle such as an automobile.

  2. Description of the Related Art In recent years, so-called IDS control (idling stop control) has been widely adopted for vehicles driven by an engine for the purpose of improving fuel efficiency. In the IDS control, for example, when the brake pedal is depressed with the driver's foot to operate the brake and the vehicle speed falls below a predetermined idling stop execution vehicle speed, the engine is automatically stopped (idling stop). After the automatic stop of the engine, for example, when the foot is released from the brake pedal and the brake is released, the engine is automatically restarted (IDS return).

  When the engine is restarted, a voltage is applied from a battery to a starter attached to the engine, and the power of the starter is transmitted to a flywheel of the engine via a starter gear, whereby the engine is cranked. Then, the engine is restarted by sparking the spark plug of the engine while the engine is cranked.

JP-A-9-107640

  Since the operating power of the starter is large, the terminal voltage of the battery (battery voltage) is greatly reduced when the engine is restarted. The battery is charged by the power generated by the alternator. If the terminal voltage of the battery rises slowly due to this charge, and if the stop and restart of the engine by the IDS control are repeated in a short period of time, the amount of discharge from the battery becomes larger than the amount of charge to the battery (the balance of the amount of electricity). Is minus), and the terminal voltage of the battery is greatly reduced.

  In order to accelerate the rise of the terminal voltage of the battery, the field current supplied to the field coil of the alternator may be increased to increase the power generation of the alternator. However, when the field current suddenly increases, the rotational resistance of the crankshaft of the engine rapidly increases, and the rotational stability of the engine is impaired.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device for a vehicle, which can accelerate the rise of a terminal voltage of a battery at the time of restarting an engine by IDS control, while ensuring rotation stability (stall resistance) of the engine. It is.

  In order to achieve the above object, a control device for a vehicle 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 a mounted vehicle, wherein the engine is stopped in response to a predetermined IDS start condition being satisfied, and a starter is switched from a battery in response to a predetermined IDS return condition being satisfied during the stop. Control means for performing IDS control for restarting the engine by operating the starter by supplying power to the power supply, and power generation control means for controlling power generation of the generator so that the terminal voltage of the battery matches the target voltage. The power generation control means increases the target voltage from an initial value larger than a normal value to a final value when the engine is restarted by the IDS control. In is gradually changing to gradually increase the terminal voltage of the battery is performed gradually gradual excitation control for increasing the power generation current of the generator until it matches the target voltage.

  According to this configuration, in the IDS control, when a predetermined IDS start condition is satisfied, the engine is stopped (idling stop). Then, when a predetermined IDS return condition is satisfied while the engine is stopped, the starter is operated, and the engine is cranked by the power of the starter. Then, the engine is restarted by sparking the spark plug of the engine while the engine is cranked.

  Power generation by the generator is controlled so that the terminal voltage of the battery matches the target voltage which is the target value. When the engine is restarted, the initial value of the target voltage is set to a value larger than the normal value. Thus, power generation by the generator is started with good responsiveness to a decrease in the terminal voltage of the battery accompanying the start of the starter. As a result, the rise of the terminal voltage of the battery can be hastened.

  When the engine is restarted, gradual excitation control is performed to gradually increase the current generated by the generator until the terminal voltage of the battery matches the target voltage. By the gradual excitation control, it is possible to suppress a sudden increase in the rotational resistance of the engine due to a sudden increase in the generated current of the generator.

  Then, in addition to the gradual excitation control, the target voltage is gradually changed so as to gradually increase from the initial value to the final value. Thus, after the gradual excitation control is performed until the terminal voltage of the battery matches the target voltage, the terminal voltage of the battery can be further increased with the gradual change of the target voltage. Therefore, it is possible to prevent the amount of discharge from the battery from being larger than the amount of charge to the battery (the balance of the amount of electricity becomes negative).

  Therefore, the rising of the terminal voltage of the battery at the time of restarting the engine by the IDS control can be hastened while ensuring the rotation stability of the engine. Furthermore, in addition to the rapid rise of the terminal voltage, the amount of discharge from the battery is suppressed from being larger than the amount of charge to the battery. Therefore, even if the engine is stopped and restarted by the IDS control repeatedly. In addition, it is possible to suppress a large decrease in the terminal voltage of the battery. As a result, early deterioration of the battery can be suppressed.

  Further, in a configuration in which the initial value of the target voltage is set to the same value as the final value and the target voltage is not gradually changed, the terminal voltage of the battery may rise rapidly, and a problem such as flickering of the headlight may occur. In the configuration in which the target voltage is gradually changed, it is possible to suppress a sudden increase in the terminal voltage of the battery, and to suppress the occurrence of a problem such as flickering of the headlight.

  The generator may be an alternator. In this case, in the gradual excitation control, the power generation current of the generator is gradually increased by gradually increasing the duty ratio of the current supplied to the field coil (rotor coil) of the alternator.

  The normal value of the target voltage is almost the same value as the nominal voltage of the battery, the initial value larger than the normal value is a value obtained by multiplying the nominal voltage of the battery by a first coefficient larger than 1, and the final value is the battery value. May be multiplied by a second coefficient larger than the first coefficient.

  ADVANTAGE OF THE INVENTION According to this invention, the rising of the terminal voltage of a battery at the time of restart of an engine by IDS control can be accelerated, ensuring rotation stability of an engine.

1 is a block diagram illustrating 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 flowchart which shows the flow of IDS control. 5 is a timing chart for describing power generation control executed at the time of IDS return.

  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 on which an ECU 11 according to one embodiment of the present invention is mounted.

  The vehicle 1 is an automobile driven by the engine 2. A starter 3 for cranking the engine 2 and an alternator 4 for generating electric power by rotation of the engine 2 are provided along with the engine 2. The vehicle 1 has a battery 5 mounted thereon. 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. The 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. Also, the relay provided on the starter 3 is turned on, the current supplied from the battery 5 to the starter 3 increases, and a large torque is input from the starter 3 to the engine 2, and the engine 2 is cranked by the torque. You. While the engine 2 is being cranked, the spark plug of the engine 2 is sparked, so that the engine 2 starts.

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

  The IC regulator controls the duty ratio FDUTY of the field current supplied to the field coil. The power generation amount of the alternator 4 increases as the duty ratio FDUTY of the field current increases, and the power generation amount of the alternator 4 decreases as the duty ratio FDUTY decreases.

  The vehicle 1 is provided with an ECU (Electronic Control Unit) including a CPU, a memory, and the like. Each ECU is connected to be capable of bidirectional communication by a CAN (Controller Area Network) communication protocol.

  The plurality of ECUs include the ECU 11. The ECU 11 includes an accelerator sensor that outputs a detection signal corresponding to the operation amount of the accelerator pedal, an engine speed sensor that outputs a pulse signal synchronized with the rotation of the crankshaft of the engine 2 as a detection signal, and an electronic throttle valve of the engine 2. Various sensors such as a throttle opening sensor that outputs a detection signal corresponding to the opening (throttle opening) are connected. Further, a terminal voltage (battery voltage) of the battery 5 is input to the ECU 11.

  The ECU 11 starts and stops the engine 2 based on information obtained from detection signals of various sensors and / or various information input from other ECUs, and controls the electronic throttle valve of the engine 2. Controls injectors and spark plugs. Further, the ECU 11 sets a target voltage which is a target value of the battery voltage, generates a voltage adjustment signal based on a difference between the target voltage and the battery voltage, and outputs the voltage adjustment signal to the IC regulator of the alternator 4. When the voltage adjustment signal is received by the IC regulator, the IC regulator controls the duty ratio FDUTY of the field current of the alternator 4 based on the voltage adjustment signal.

<IDS control>
FIG. 2 is a flowchart showing the flow of the IDS control.

  The vehicle 1 employs IDS control (idling stop control).

  In the IDS control, when the brake pedal is operated (depressed) while the vehicle 1 is running, the ECU 11 determines whether a predetermined IDS start condition is satisfied (step S1). 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 predetermined time or more. While the brake pedal is operated, it is determined at regular intervals whether or not the IDS start condition is satisfied.

  When the IDS start condition is satisfied (YES in step S1), the engine 11 is stopped (idling stop) by the ECU 11 (step S2).

  After the start of the idling stop, the ECU 11 determines whether a predetermined IDS return condition is satisfied (step S3). The IDS return condition is, for example, a condition that the operation of the brake pedal is released during idling stop (the driver's foot is released from the brake pedal). During idling stop, it is determined at regular intervals whether or not the IDS start condition is satisfied.

  When the IDS return condition is satisfied (YES in step S3), the starter 3 is operated by the ECU 11. By the operation of the starter 3, the engine 2 is cranked. When the spark plug of the engine 2 is sparked during the cranking of the engine 2, the engine 2 is restarted (step S4), and the IDS control is terminated.

  It should be noted that an ECU other than the ECU 11, for example, an IDSECU for 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 establishment of the IDS start condition, and the engine 11 is stopped by the ECU 11 in response to the engine stop request. The IDSECU determines whether the IDS return condition is satisfied. Then, when the IDS return condition is satisfied, an engine restart request is transmitted from the IDSECU to the ECU 11, and the engine 2 is restarted by the ECU 11 in response to the engine restart request.

<Power generation control>
FIG. 3 is a timing chart for explaining the power generation control executed when the engine 2 is restarted (when the IDS returns) by the IDS control.

  When the IDS return condition is satisfied, the target value of the battery voltage is increased from the normal value to the initial value larger than the normal value by the ECU 11 (time T1).

  When a voltage is applied to the starter 3 to restart the engine 2 and a relay incorporated in the starter 3 is turned on, the current supplied from the battery 5 to the starter 3 increases, and the engine 2 , A large torque is input, and the engine 2 is cranked by the torque. As the current supplied to the starter 3 increases, the battery voltage drops sharply.

  Due to the sudden drop of the battery voltage, the difference between the battery voltage and the target voltage increases. Therefore, when the ECU 11 generates the voltage adjustment signal such that the duty ratio FDUTY of the field current supplied to the field coil of the alternator 4 has a duty ratio corresponding to the difference between the battery voltage and the target voltage, the field current is reduced. As a result, the rotational resistance of the crankshaft of the engine 2 rapidly increases, and the rotational stability of the engine 2 is impaired.

  Therefore, the gradual excitation control is performed until the battery voltage matches the target voltage. In the gradual excitation control, the ECU 11 generates a voltage adjustment signal based on the difference between the battery voltage and the target voltage so that the duty ratio FDUTY of the field current increases at a predetermined rate of change. Thereby, the generated current of the alternator 4 gradually increases.

  On the other hand, the target voltage is gradually changed from the initial value to the final value larger than the initial value so as to gradually increase over time T1-T2. Thus, after the gradual excitation control is performed until the battery voltage matches the target voltage, the battery voltage further increases as the target voltage gradually changes.

  The target voltage is reduced from the final value to a normal value when a condition for permitting execution of the IDS control (IDS permission condition) is satisfied. An example of the IDS permission condition is a condition that the vehicle speed of the vehicle 1 has increased to a predetermined speed or more.

  The normal value of the target voltage is substantially the same as the nominal voltage of the battery 5 (for example, 12 V). For example, the initial value is set to a value obtained by multiplying the nominal voltage of the battery 5 by a first coefficient larger than 1. Then, the final value may be set to a value obtained by multiplying the nominal voltage of the battery 5 by a second coefficient larger than the first coefficient.

  Further, the concept of the coincidence between the battery voltage and the target voltage includes that the battery voltage is within a predetermined range including the target voltage. That is, when the difference between the battery voltage and the target voltage is equal to or smaller than a certain value, it may be determined that the battery voltage matches the target voltage.

<Effects>
As described above, in the IDS control, when a predetermined IDS start condition is satisfied, the engine 2 is stopped (idling stop). When a predetermined IDS return condition is satisfied while the engine 2 is stopped, the starter 3 is operated, and the engine 2 is cranked by the power of the starter 3. Then, the engine 2 is restarted by sparking the spark plug of the engine 2 while the engine 2 is cranked.

  The power generation by the alternator 4 is controlled so that the battery voltage matches the target voltage which is the target value. When the engine 2 is restarted, the initial value of the target voltage is set to a value larger than the normal value. As a result, power generation by the alternator 4 is started with good responsiveness to a decrease in battery voltage due to the start of the starter 3. As a result, the rise of the battery voltage can be hastened.

  When the engine 2 is restarted, gradual excitation control is performed to gradually increase the current generated by the alternator 4 until the battery voltage matches the target voltage. By the gradual excitation control, it is possible to suppress a sudden increase in the rotational resistance of the engine 2 due to a sudden increase in the generated current of the alternator 4.

  Then, in addition to the gradual excitation control, the target voltage is gradually changed so as to gradually increase from the initial value to the final value. Thus, after the gradual excitation control is performed until the battery voltage matches the target voltage, the battery voltage can be further increased with the gradual change of the target voltage. Therefore, it is possible to prevent the amount of discharge from the battery 5 from being larger than the amount of charge to the battery 5 (the balance of the amount of electricity becomes negative).

  Therefore, the rising of the battery voltage at the time of restarting the engine 2 by the IDS control can be hastened while securing the rotational stability of the engine 2. Further, in addition to the rapid rise of the battery voltage, the amount of discharge from the battery 5 is suppressed from being larger than the amount of charge to the battery 5, so that the stop and restart of the engine 2 by the IDS control are repeated. Even so, it is possible to suppress a large decrease in the battery voltage. As a result, early deterioration of the battery 5 can be suppressed.

  Further, in a configuration in which the initial value of the target voltage is set to the same value as the final value and the target voltage is not gradually changed, the terminal voltage of the battery 5 may rise sharply and a problem such as flickering of the headlight may occur. In the configuration in which the target voltage is gradually changed, it is possible to suppress a sudden increase in the terminal voltage of the battery 5 and to suppress occurrence of a problem such as flickering of the headlight.

<Modification>
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented in another form.

  In the above-described embodiment, the gradual change of the target voltage is started at the same time when the target value of the battery voltage is increased from the normal value to the initial value. However, the gradual change of the target voltage is started at a later timing. May be done.

  For example, the gradual change of the target voltage may be started at the timing when the engine 2 first explodes. In this case, the gradual change of the target voltage can be started almost simultaneously with the start of power generation by the alternator 4.

  Further, the gradual change of the target voltage may be started at a timing when the engine 2 completely explodes. In this case, the target voltage can be gradually changed after the rotation state of the engine 2 and the power generation state by the alternator 4 are stabilized, so that the rotation stability of the engine 2 can be further suppressed from being impaired.

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

Reference Signs List 1 vehicle 2 engine 3 starter 4 alternator (generator)
5 Battery 11 ECU (control device, IDS control means, power generation control means)

Claims (1)

An engine, a starter for cranking the engine, a generator that generates electric power by rotation of the engine, and a control device used for a vehicle equipped with a battery that is charged with electric power generated by the generator,
The engine is stopped in response to a predetermined IDS start condition being satisfied, and the starter is supplied by supplying power from the battery to the starter in response to a predetermined IDS return condition being satisfied while the engine is stopped. IDS control means for operating and performing IDS control for restarting the engine;
Power generation control means for controlling the power generation of the generator so that the terminal voltage of the battery matches the target voltage,
The power generation control means gradually changes the target voltage from an initial value larger than a normal value to a final value when the engine is restarted by the IDS control, so that the terminal voltage of the battery becomes equal to the target voltage. A control device for a vehicle, which executes a gradual excitation control for gradually increasing a generated current of the generator until the power generation current matches.

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