JP2018172098A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device capable of appropriately stopping a motor driven to start an engine. SOLUTION: When a predetermined time has elapsed from the start of ISG for starting the engine (T2), the ISG torque is reduced. At this time, if the engine has already exploded completely, the engine speed does not decrease, or even if it decreases, the amount of decrease is small. On the other hand, when the engine is not completely detonated, the engine speed decreases significantly when the ISG torque is reduced. Therefore, it is determined whether or not the engine is completely detonated based on the change in the engine speed after the ISG torque is reduced (T3), and the ISG stop is determined based on the determination result. [Selection diagram] Figure 2

Description

  The present invention relates to a vehicle control device.

  Conventionally, a hybrid system using an engine as a main drive source and using an ISG (integrated starter generator) for driving assistance is known.

  The ISG has both a motor function that generates power by supplying power and a generator function that regenerates power to power. The ISG is capable of assisting driving with a motor function, and can be used as an engine starter with a motor function. The ISG can increase the engine speed to near or higher than the idle speed, and can maintain the engine speed at the speed after the increase.

Japanese Patent Laid-Open No. 2015-203350

  When the engine is started by the ISG, the ISG increases the engine speed to a speed near or higher than the idle speed. Therefore, the threshold value (complete explosion determination rotational speed) used for determining whether or not the engine has completely exploded is set to a higher rotational speed than in the case of engine start by the starter. Therefore, even if the engine is completely detonated, if the combustion state at the start is poor, the engine speed does not exceed the complete explosion determination speed and the ISG is not turned off. And there is concern about the deterioration of feeling.

  The objective of this invention is providing the control apparatus for vehicles which can stop the motor driven for engine starting appropriately.

  In order to achieve the above object, a vehicle control apparatus according to the present invention is a control apparatus used in a vehicle equipped with an engine and a motor for starting the engine, and drives the motor to reduce the engine speed. Starting means for increasing, and a stop determining means for reducing the torque of the motor after a predetermined time has elapsed from the start of driving of the motor by the starting means, and determining stop of the motor from a change in the engine speed after the reduction. including.

  According to this configuration, when a predetermined time has elapsed from the start of driving of the motor for starting the engine, the torque of the motor is reduced. At this time, if the engine has already completely exploded, the engine speed does not decrease, or even if it decreases, the amount of decrease is small. On the other hand, when the engine is not completely exploded, when the motor torque is reduced, the engine speed is greatly reduced. Therefore, it is possible to determine whether or not the engine has completely exploded from the change in the engine speed after the motor torque is reduced, and it is possible to determine the stop of the motor from the result of the determination. As a result, the motor can be appropriately stopped when the engine is completely exploded.

  ADVANTAGE OF THE INVENTION According to this invention, the motor driven for engine starting can be stopped appropriately. Therefore, it is possible to suppress the power consumption due to the motor being kept on, and to improve the feeling when starting the engine.

It is a figure which shows the structure of the principal part of the vehicle 1 by which the control apparatus which concerns on one Embodiment of this invention is mounted. It is a figure which shows the time change of the ISG torque at the time of engine starting, and engine speed NE (complete explosion, incomplete explosion). It is a flowchart which shows the other determination methods of the complete explosion at the time of engine starting, and an incomplete explosion.

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

<Vehicle configuration>
FIG. 1 is a diagram illustrating a configuration of a main part of a vehicle 1 on which a control device according to an embodiment of the present invention is mounted.

  The vehicle 1 is equipped with a hybrid system that uses an engine 11 as a main drive source and an ISG (integrated starter generator) 12 for driving assistance.

  The engine 11 is, for example, a gasoline engine. The engine 11 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 11, an injector (fuel injection device) that injects fuel into the intake air, and an ignition plug that generates electric discharge in the combustion chamber. It has been.

  The ISG 12 has both a motor function that generates power by supplying power and a generator function that regenerates power to power. The ISG 12 is capable of driving assistance with a motor function, and is provided so that it can be used as a starter for the engine 11 with a motor function. When the ISG 12 functions as a motor, power is supplied to the ISG 12 via an inverter from an assist sub-battery 13 provided separately from a main battery (not shown) made of a 12V (volt) lead battery. When the ISG 12 functions as a generator, the power generated by the ISG 12 is supplied from the ISG 12 to the assisting sub-battery 13 via the inverter.

  The vehicle 1 includes an ECU (Electronic Control Unit) having a configuration including a microcomputer (microcontroller unit). The microcomputer includes, for example, a CPU, ROM and RAM, data flash (flash memory), and the like. Although only one ECU 21 for controlling the engine 11 and the ISG 12 is shown in FIG. 1, a plurality of ECUs having the same configuration as the ECU 21 are mounted on the vehicle 1 in order to control each part. Yes. The plurality of ECUs including the ECU 21 are connected so as to be capable of bidirectional communication using a CAN (Controller Area Network) communication protocol.

  Various sensors necessary for control are connected to the ECU 21. As an example, the ECU 21 is connected to an engine rotation sensor 22 that outputs a pulse signal synchronized with the rotation of the engine 11 (rotation of the crankshaft) as a detection signal.

  The ECU 21 acquires (detects) the rotational speed (engine rotational speed) of the engine 11 from the detection signal of the engine rotational sensor 22. The ECU 21 is configured to start, stop and adjust the output of the engine 11 based on information acquired from detection signals of various sensors and / or various information input from other ECUs. The injector and spark plug, and the ISG 12 are controlled. Further, the ECU 21 calculates the remaining battery level that is the remaining charge amount of the assisting sub-battery 13, and SOC (State Of Charge) that is the ratio of the remaining battery level to the charging capacity (full charge amount) of the assisting sub-battery 13. Based on the above, the power generation by the ISG 12 and the travel assist by the ISG 12 are controlled.

<Engine start control>
FIG. 2 is a diagram showing temporal changes in the output torque of the ISG 12 and the engine speed NE (complete explosion, incomplete explosion) when the engine 11 is started.

  When starting the engine 11, the ISG 12 is used as a starter. When the supply of power to the ISG 12 is started (time T1) and the torque of the ISG 12 (ISG torque) is input to the crankshaft of the engine 11, the engine 11 is cranked by the torque. Then, the spark plug is sparked while the engine 11 is cranked.

  Due to the cranking, the engine speed of the engine 11 rises to the vicinity of the rotational speed (complete explosion determination rotational speed) that is a criterion for the complete explosion of the engine 11. When the engine 11 starts normally, the spark plug is sparked while the engine 11 is cranked, so that the engine 11 is completely detonated, and the engine speed is completed as shown by a two-dot chain line in FIG. It rises above the explosion judgment speed. However, when the combustion state at the start of the engine 11 is poor, even if the engine 11 completes an explosion, as shown by the solid line in FIG. is there.

  When a predetermined time has elapsed from the start (start) of driving of the ISG 12, the ISG torque is reduced (time T2). At this time, the engine speed necessary for starting the engine 11 is ensured. When the engine 11 is completely exploded, even if the combustion state of the engine 11 is bad, the engine speed does not decrease greatly. On the other hand, when the engine 11 is not completely detonated, the engine speed greatly decreases as the ISG torque decreases.

  When the engine speed decreases by a predetermined number or more according to the decrease in the ISG torque, the ECU 21 determines that the engine 11 has not completely exploded. Then, the ISG torque is increased again (time T3), and the cranking of the engine 11 is continued.

  If the engine speed does not decrease even if the ISG torque is reduced, or if the reduction range is less than the predetermined speed even if the ISG torque is reduced, the ECU 21 determines that the engine 11 has completely exploded, and the ISG 12 is stopped ( Time T3).

<Effect>
As described above, when a predetermined time has elapsed from the start of driving of the ISG 12 for starting the engine 11, the torque of the ISG 12 is reduced. At this time, if the engine 11 has already completed an explosion, the engine speed does not decrease, or even if it decreases, the amount of decrease is small. On the other hand, when the engine 11 has not completely exploded, when the torque of the ISG 12 is reduced, the engine speed is greatly reduced. Therefore, it is possible to determine whether or not the engine 11 has completely exploded from the change in the engine speed after the torque of the ISG 12 is reduced, and it is possible to determine the stop of the ISG 12 from the result of the determination. As a result, the ISG 12 can be appropriately stopped when the engine 11 is completely exploded, and power consumption due to the ISG 12 being kept on can be suppressed. Moreover, the feeling at the time of engine 11 starting can be improved.

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

  For example, if the ISG torque is reduced when the engine 11 is in an incomplete explosion, the engine speed is greatly reduced. Even if the ISG torque is reduced while the engine 11 is in a complete explosion, the engine speed is not greatly reduced. Thus, the complete explosion and incomplete explosion (stop of ISG 12 and continued driving) of engine 11 may be determined from the change in rotational acceleration of engine 11 after the ISG torque is reduced.

  Specifically, as shown in FIG. 8, the ISG 12 is started as a starter (step S1), and when a predetermined time has elapsed from the start (YES in step S2), the ISG torque is reduced (step S3). If the change in the rotational acceleration of the engine 11 in response to the decrease in the ISG torque is less than the threshold value (YES in step S4), it is determined that the engine 11 has completely exploded (step S5). If the change in rotational acceleration is equal to or greater than the threshold value (NO in step S4), it may be determined that the engine 11 has not yet completed explosion (step S6).

  When the engine 11 is incomplete explosion, the change in rotational acceleration appears earlier than the change in rotational speed. Therefore, in the method for determining whether the engine 11 has completed explosion or incomplete explosion from the change in rotational acceleration, the time required for the determination is reduced. Can be achieved.

  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 11: Engine 12: ISG (motor)
21: ECU (control device)

Claims (1)

A control device used in a vehicle equipped with an engine and a motor for starting the engine,
Starting means for driving the motor to increase the rotational speed of the engine;
Stop determining means for reducing the torque of the motor after a predetermined time has elapsed from the start of driving of the motor by the starting means and determining stop of the motor from a change in the engine speed after the reduction; A vehicle control device.

Images