JP2012002068A - Method of controlling generator of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the torque fluctuation of an internal combustion engine by making it possible to increase the load to the internal combustion engine of an generator.SOLUTION: In the method of controlling the generator of the internal combustion engine in which the internal combustion engine has the generator, the generator supplies the power to the secondary battery mounted on an automobile, and the generator generates power at the timing of absorbing the fluctuation of an output torque of the engine while the internal combustion engine is operated at an engine rotational speed not more than a predetermined rotational speed, charging is stopped at the time point when the charging capacity of the battery exceeds a predetermined value when the engine rotational speed is detected and in the case it is determined that the detected engine rotational speed exceeds the predetermined rotational speed.

Description

  The present invention relates to a method for controlling a generator attached to an internal combustion engine mounted on a vehicle such as an automobile.

  Conventionally, this type of internal combustion engine includes a generator (hereinafter referred to as an alternator) that charges a battery mounted on a vehicle and functions as a power source for electrical components. The alternator generates electric power when the rotational force of the crankshaft is transmitted by the belt.

  By the way, in the internal combustion engine, during low-speed operation such as idle operation, the torque on the crankshaft varies depending on the moving direction of the piston, that is, each stroke. An attempt to smooth the rotation of the internal combustion engine by controlling the power generation of the alternator in accordance with such torque fluctuation is known (for example, Patent Document 1). Specifically, the alternator is operated in the section including the expansion stroke to generate power, and when the torque increases, the reverse torque generated by the alternator, that is, the torque that acts to cancel the torque of the internal combustion engine, It is intended to balance the torque with other than the expansion stroke.

  In such alternator power generation control, the alternator is operated in accordance with the expansion stroke, but when the vehicle is running and the battery is fully charged, the power generation amount of the alternator is reduced accordingly. . In this way, when the amount of power generated by the alternator is reduced, the alternator does not become a load on the internal combustion engine, in other words, the reverse torque generated by the alternator suppresses higher torque than the other strokes in the expansion stroke of the internal combustion engine. Can not do. Therefore, it becomes difficult to suppress the rotational fluctuation of the internal combustion engine.

2009-89466

  Accordingly, the present invention focuses on the above points and aims to suppress the torque fluctuation of the internal combustion engine by increasing the load on the internal combustion engine of the generator.

  That is, according to the method for controlling a generator of an internal combustion engine of the present invention, the internal combustion engine includes a generator, the generator supplies electric power to a storage battery mounted on the vehicle, and the internal combustion engine rotates at an engine speed equal to or less than a predetermined rotational speed. A generator control method for an internal combustion engine that causes a generator to generate power at a timing of absorbing fluctuations in engine output torque when the engine is operated at a number, wherein the engine speed is detected, and the detected engine speed is When it is determined that the rotation speed exceeds a predetermined number of revolutions, charging is stopped when the charge capacity of the storage battery exceeds a predetermined value.

  According to such a configuration, when the internal combustion engine is operated at an engine speed exceeding a predetermined speed, charging is performed only until the charging capacity of the storage battery exceeds a predetermined value. For this reason, uncharged capacity is ensured in the storage battery. When the internal combustion engine is operated at a rotational speed equal to or lower than a predetermined rotational speed, since the uncharged capacity is secured, the load on the generator can be increased. Moreover, since the battery is not charged until it is fully charged when operating at a predetermined speed or higher, it is possible to reduce fuel consumption required for charging.

  The present invention is configured as described above, and when the internal combustion engine is operated at a rotational speed equal to or lower than a predetermined rotational speed, the load on the generator can be increased and torque fluctuations of the internal combustion engine can be absorbed. In addition, it is possible to reduce the fuel consumption required for charging when operating at a predetermined rotational speed or higher.

The block diagram which shows the whole structure of embodiment of this invention. The flowchart which shows the control procedure of the embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The engine 1 of this embodiment is, for example, a two-cylinder spark ignition type mounted on a vehicle, and is an equidistant explosion type in which the strokes of the first cylinder and the second cylinder are separated by 360 °. The engine 1 includes an alternator 2 with an IC regulator that is a three-phase AC generator. The engine itself is not limited to a two-cylinder engine, and various engines widely known in this field can be applied.

  The alternator 2 obtains driving force from the engine 1 through the pulley 3 and the belt 4 to generate electric power. The alternator 2 rectifies the generated three-phase alternating current into direct current by an IC regulator (not shown) integrally attached thereto, and a charger and electronic control of a storage battery (hereinafter referred to as a battery) 5 mounted on the vehicle. It functions as a power source for the device 6 and the electrical component 7. The alternator 4 having such a configuration may be one that is widely known in this field.

  Specifically, the alternator 4 includes a rotor coil (field coil) and a stator coil, and controls the current supplied to the rotor coil by an IC regulator to control the amount of AC power generated in the stator coil. is there. The IC regulator is controlled by an electronic control unit 6 that controls the operating state of the engine 1. The alternator 4 can generate electricity at three kinds of voltages: a high voltage, a low voltage lower than the high voltage and substantially equal to the battery terminal voltage at full charge, and 0 volt by controlling energization to the rotor coil. it can.

  The electronic control unit 6 is mainly composed of a computer system including a central processing unit, a storage device, an input interface, and an output interface. From the various sensors, the electronic control unit 6 is used to grasp the operating state of the engine 1. Based on the output signal sent, the operating state of the engine 1 is controlled. Specifically, these sensors include a rotational speed sensor for detecting the rotational speed of the crankshaft and hence the rotational speed of the engine 1, an intake pressure sensor for detecting the intake pipe pressure, a crank angle signal attached to the camshaft, and a cylinder. Examples include a crank sensor that outputs a discrimination signal. Further, in order to detect the state of charge of the battery 5, voltage detection means (voltmeter) for detecting the voltage between the terminals of the battery 5 and current detection means (ammeter) for detecting the discharge current of the battery 5 Is connected to the electronic control unit 6. The electronic control unit 6 integrates the charge / discharge amount of the battery 5 based on the output signals from the voltage detection unit and the current detection unit.

  The electronic control unit 6 controls the alternator 2 so that the alternator 2 generates power at a timing of absorbing fluctuations in engine output torque when the engine 1 is operated at an engine speed equal to or lower than a predetermined speed. Thus, when it is determined that the detected engine speed exceeds a predetermined engine speed, a control program for the alternator 2 that stops charging when the charge capacity of the battery 5 exceeds a predetermined value is incorporated. The control procedure of the alternator 2 will be described with reference to FIG. The control program for the alternator 2 is repeatedly executed at predetermined intervals while the engine 1 is operating.

  First, in step S1, the engine speed is detected based on an output signal output from the speed sensor.

  In step S2, it is determined whether or not the detected engine speed is equal to or higher than a predetermined speed. The predetermined rotational speed is set to a value that causes fluctuations in the engine rotational speed when the engine 1 is operating. In the engine 1 of this embodiment, the predetermined rotational speed is set to a low rotational speed that is higher than the idling rotational speed when there is no load. If it is determined in step S2 that the engine speed is equal to or higher than the predetermined speed, the process proceeds to step S3.

  In step S3, it is determined whether or not the charge capacity of the battery 5 is greater than or equal to a predetermined amount. For example, the charge capacity is measured by integrating the charge / discharge amount of the battery 5. For example, the predetermined amount is set to about 70% of the full charge amount so that the electric power generated by the alternator 2 can be charged in accordance with the torque fluctuation when the engine speed is less than the predetermined speed. Set. If it is determined in step S3 that the charge capacity is equal to or greater than the predetermined value, the process proceeds to step S4.

  In step S4, the charging of the battery 5 is stopped. On the other hand, if it is determined in step S2 that the engine speed is less than the predetermined speed, and if it is determined in step S3 that the charging capacity is less than the predetermined amount, the battery 5 is removed in step S5. Charge.

  In such a configuration, when the engine 1 is started, the battery 5 is charged by executing Steps S1, S2 and S5 in a state where the engine speed does not reach the predetermined speed. In this case, the electronic control unit 6 outputs a power generation instruction to the alternator 2 regardless of the state of charge of the battery 5. In this case, the alternator 2 continues to generate power at the high voltage and is supplied to the battery 5 and the electrical component 7.

  In this way, in the operating state of the engine 1 where the engine speed is less than the predetermined speed, the battery 5 is charged. In this embodiment, the power generation amount of the alternator 2 is controlled according to the charged state of the battery 5 is doing. Specifically, when the charge amount of the battery 5 is equal to or less than the set lower limit charge amount (approximately the remaining charge amount that can be used as the power source of the electrical component 7), the alternator 2 is always caused to generate power and the battery 5 is Charge. Thereafter, the charge amount has changed to a state where the charge amount exceeds the lower limit charge amount and is equal to or less than the set upper limit charge amount (almost full charge amount), that is, when the battery 5 is charged exceeding the lower limit charge amount, The amount of charge is controlled by intermittently generating power at a high voltage, in other words, intermittently generating power at a high voltage. When the charge amount is equal to or greater than the upper limit charge amount, power generation is stopped and power supply to the electrical component 7 is performed only from the battery 5. In this way, by changing the power generation control of the alternator 2 depending on the state of charge of the battery 5, the manner in which the load is applied to the engine 1 is controlled to suppress rotational fluctuations.

  Next, when the engine speed becomes equal to or higher than the predetermined speed due to acceleration or the like, the charge state of the battery 5 is determined in step S3. Run to charge the battery 5 to a predetermined amount. On the other hand, if it is determined in step S3 that the charging capacity is equal to or greater than the predetermined amount, step S4 is executed to stop charging the battery 5. In this case, power generation of the alternator 2 is stopped completely, or the alternator 2 is generated at a low voltage to suppress the discharge of the battery 5 so that the charge amount of the battery 5 does not fall below a predetermined amount. Control power generation voltage and continue power generation. That is, stopping the charging of the battery 5 does not stop the power generation of the alternator 2.

  In this case, the generated power is consumed in the electronic control device 6 and the electrical component 7, but is insufficient if the generated power is less than the power consumption of the electronic control device 6 and the electrical component 7. Minutes are supplied from the battery 5. Therefore, when the battery 5 is discharged, the power generation of the alternator 2 is controlled as described above according to the operating state of the engine 1 and the charged state of the battery 5.

  In this way, when the engine speed increases to a predetermined speed or more and the charging capacity of the battery 5 reaches a predetermined amount, the charging of the battery is stopped, so the uncharged capacity from the predetermined amount to the full charge amount Can be secured. As a result, when the engine 1 is operated at a speed lower than the predetermined rotational speed, the load of the alternator 2 on the engine 1 increases. That is, the reverse torque generated by the alternator 2 for the engine 1 can be increased.

  By controlling the alternator 2 in this way, the reverse torque generated by the alternator 2 acts as a brake on the engine 1 when the rotational speed of the engine 1 rotating at a low rotational speed increases. As a result, The torque fluctuation of the engine 1 is absorbed by the reverse torque canceling out the torque at the time of the torque fluctuation of the engine 1. Therefore, rotational fluctuation of the engine 1 can be suppressed, and drivability can be improved.

  Further, when the engine 1 is operated at a predetermined speed or higher, the alternator 2 is not operated until the battery 5 is fully charged, so that the output of the engine 1 required for charging becomes unnecessary, thereby reducing fuel consumption. can do.

  Note that the alternator 2 may be controlled in accordance with the torque that varies in accordance with the expansion stroke of each cylinder. In this case, the angular velocity is calculated based on the crank angle signal output from the crank sensor, the torque variation is detected based on the obtained angular velocity, and the alternator 2 generates power at the timing when the torque variation increases. In addition, the alternator 2 is controlled so as to stop the power generation of the alternator 2 in accordance with the timing when the fluctuation of the torque decreases. Thus, by controlling the power generation state of the alternator 2 in accordance with torque fluctuations such as the expansion stroke of each cylinder, fluctuations in the rotation of the engine 1 can be suppressed more smoothly.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  Examples of utilization of the present invention include those for a two-cylinder gasoline engine and a small displacement internal combustion engine in which torque fluctuations in the low-speed operation region are likely to become obvious.

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Alternator 5 ... Battery 6 ... Electronic control unit 7 ... Electrical component

Claims (1)

The internal combustion engine includes a generator, and the generator supplies electric power to a storage battery mounted on the vehicle. When the internal combustion engine is operated at an engine speed equal to or lower than a predetermined speed, fluctuations in engine output torque are generated. A method for controlling a generator of an internal combustion engine that causes a generator to generate power at a timing of absorption,
Detects the engine speed,
A control method for a generator of an internal combustion engine, which stops charging when a charging capacity of a storage battery exceeds a predetermined value when it is determined that the detected engine speed exceeds a predetermined speed.

Images