JPH08266097A - Alternator control method - Google Patents

Abstract

(57) [Abstract] [Purpose] The amount of power generated by the alternator is controlled at least according to the state of the electrical load. The amount of power generated by an alternator, which has an IC regulator that adjusts the amount of electricity supplied to a rotor coil according to a change in voltage of a driving power source that is mechanically driven by an engine and is selectively connected to an electric load, In the control method of the alternator, the control means detects the input of the electric load from the duration of the charging request signal output from the IC regulator based on the voltage of the driving power source, Before the electric load is turned on, the power generation prohibition signal output from the control means to the IC regulator is invalidated to control the amount of power generation according to the charge request signal, and after the electric load is turned on, the prohibited state is gradually changed. While shortening the power generation prohibition signal, the power generation amount is gradually increased while the power generation prohibition signal is enabled and the charge request signal is being output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an alternator used in an engine of an automobile or the like.

[0002]

2. Description of the Related Art Many of the alternators widely used in recent automobiles have an IC regulator inside a casing. The IC regulator adjusts the output current of the alternator by adjusting the current flowing through the rotor coil. It is common to do so. The IC regulator has its power input terminal connected to a driving power source (battery) via a key switch (ignition switch), and once the key switch is turned on, constant driving power is supplied to the IC regulator. It has become so. Therefore, the power generation function of the alternator is suspended only when the voltage of the charging terminal of the alternator, in other words, the voltage of the battery connected to the charging terminal exceeds the preset adjustment voltage. .

By the way, since the alternator is driven by utilizing a part of the power of the engine, the alternator operates in the engine while it is generating power and when it is not generating power. The load will be different. Therefore, if only the above control is performed, the load of the alternator may adversely affect the drivability and the like. For example, when an electric load is applied (ON) by a headlight or various electric fans (ON), the battery voltage is temporarily reduced, and the output current of the alternator is increased (the load of the alternator is increased). Fall into. Therefore, when the engine speed is as low as possible, such as during idling, engine stall may occur and idle vibration may increase.

In order to solve such a problem, as a prior art of the present invention, for example, Japanese Patent Laid-Open No. 61-17184.
As disclosed in Japanese Patent No. 0, the power supply input terminal of an IC regulator is connected to a driving power supply through a switching means provided separately from a key switch, and the switching means is appropriately opened / closed in accordance with an operating state. There is one in which an electric load applied to an engine is removed by an alternator by controlling the electric load.

[0005]

However, in such a structure, the function of the alternator itself is completely stopped at the moment when the switching means is opened. Therefore, the alternator is finely divided according to the load on the engine. It is not possible to control the alternator, and there is a risk of causing a control delay when returning.

If the alternator is provided with a control means for controlling the power generation operation in response to the load change of the engine, it becomes necessary to change the internal circuit and structure, which causes a problem. The present invention aims to solve such a problem.

[0007]

The present application takes the following means in order to achieve such an object. That is, the alternator control method of the invention according to claim 1 of the present application changes the energization amount of the rotor coil according to the voltage change of the driving power source that is mechanically driven by the engine and that is electrically connected to the electric load. A method of controlling an alternator for controlling an amount of power generation of an alternator having an IC regulator to be adjusted by an external control means, wherein the charging request signal is output from the IC regulator based on a voltage of the driving power supply. The turning on of the electric load is detected by the control means, and before the turning on of the electric load, the power generation prohibition signal output from the control means to the IC regulator is invalidated, and the power generation amount is changed according to the charge request signal. After the electric load is turned on, the prohibition state is gradually shortened and the power generation prohibition signal is enabled to output the charging request signal. Characterized by increasing the power generation amount in the period being.

The alternator control method of the invention according to claim 2 of the present application is such that the rotor coil of the rotor coil is mechanically driven by the engine and the electric load is selectively connected to the rotor coil according to the voltage change of the driving power source. A control method for an alternator, which controls an amount of power generation of an alternator having an IC regulator for adjusting an energization amount by an external control means, which has a first voltage value and a second voltage value lower than the first voltage value. An adjustment voltage switching signal is supplied to the IC regulator, the control means detects the application of the electric load based on the duration of the generated voltage of the alternator, and the voltage of the driving power supply is adjusted before the application of the electric load. The alternator is controlled so that power is generated when the voltage is below the first voltage value of the voltage switching signal, and the adjusted voltage switching signal is generated after the electric load is turned on. The characterized by increasing progressively the power generation amount by shortening the duration of the first voltage value and the second voltage value by switching alternately the second voltage value.

Further, in order to prevent the engine rotation from dropping during idle operation, the engine is equipped with an ISC actuator for controlling the intake air amount during idle operation, and the ISC actuator is opened when an electric load is detected. It is preferable that the control means gradually increases the degree of power generation, and the opening degree of the ISC actuator starts to be gradually increased, and the power generation amount is gradually increased with a delay.

[0010]

With the configuration of the invention according to claim 1 of the present application, the alternator is controlled according to the charge request signal because the power generation prohibition signal is disabled before the electric load is turned on. Generate electricity. On the other hand, when the electric load is turned on, the power generation prohibition signal output by the control means is validated, and the state of prohibiting power generation is gradually shortened to generate power during the period when the charge request signal is valid to reduce the amount of power generation. Gradually increase. Therefore, the alternator does not generate the maximum power at the same time when the electric load is applied, and the load on the engine does not suddenly increase. As a result, the engine speed will decrease and driveability will deteriorate,
Alternatively, problems such as unstable engine rotation during idling can be prevented.

With the configuration of the invention according to claim 2 of the present application, the control means outputs the adjustment voltage switching signal of the first voltage value to the IC regulator before the electric load is turned on. When the voltage of the driving power supply falls below the first voltage value of the adjustment voltage switching signal, the alternator is in a state in which it can generate power. On the other hand, when the electric load is turned on, the adjustment voltage switching signal is switched between the first voltage value and the second voltage value so that the power generation is not continuously performed, and the second voltage that prohibits the power generation. By gradually shortening the duration of the value, the power generation amount is controlled to gradually increase. Therefore, the alternator does not generate the maximum power at the same time when the electric load is applied, and the load on the engine does not suddenly increase. As a result, it is possible to prevent such problems that the engine speed is lowered and the drivability is deteriorated, or that the engine speed becomes unstable at the time of idling.

Moreover, in the engine equipped with the ISC actuator, the IS is detected when the electric load is detected.
The opening of the C actuator is gradually increased by the control means,
If the amount of power generation is gradually increased with a delay after the opening of the ISC actuator is gradually increased, it is possible to delay the increase in torque from the time when the electric load is turned on. As a result, it is possible to effectively suppress a rapid increase in the rotation of the engine.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention according to claim 1 of the present application will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an alternator, which is mechanically connected to an engine 2 so that a rotor (not shown) around which a rotor coil 1a is wound is rotationally driven according to the rotation of the engine 2. Has become. The alternator 1 includes a stator coil (not shown), an IC regulator 3, and a rotor inside a casing.
The stator coil is composed of three AC windings in a three-phase star connection, each phase of each AC winding is provided with a diode bridge of a three-phase full-wave rectifier, and each AC winding is The induced voltage induced in the full-wave is rectified and output. The positive output of the diode bridge is
It is connected to the positive terminal of the battery 4 which is the driving power source,
The negative output is grounded. The engine 2 of this embodiment is of a fuel injection type which is widely known in this field, and the operating state is controlled by calculating a fuel injection amount by an electronic control unit 5 described later. In controlling the engine 2, at least an intake system has a pressure sensor for detecting a negative pressure of an intake pipe, a cylinder head has a cam position sensor for detecting a rotational speed, and an exhaust system has an oxygen concentration of exhaust gas. An O ₂ sensor or the like is provided, and the operating state of the engine 2 is sequentially input to the electronic control unit 5 by an electric signal.

An ISC actuator 6 for adjusting the throttle opening during idle operation by a signal from the electronic control unit 5 is attached to the throttle valve of the intake system. The ISC actuator 6 is preferably a large capacity VSV provided in, for example, a bypass passage bypassing the throttle valve. If the ISC actuator 6 is configured to control the opening by changing the duty ratio (opening duty ratio) of the energization time. Good. The opening duty ratio is calculated by the electronic control unit 5 when the engine 2 is in an idle operation, depending on the engine speed, intake pressure, and the presence or absence of an electric load at that time.

The IC regulator 3 is, as shown in FIG. 1, a comparator 3 connected to the positive terminal of a battery 4.
1 and an AND circuit 32 that calculates the logical product of the charge request signal C1 output from the comparator 31 and the power generation prohibition signal C2 output from the electronic control unit 5 that is an external control means,
A switching transistor 33 connected to the AND circuit 32 to control the current flowing through the rotor coil 1a and a diode 34 for absorbing the surge voltage of the rotor coil 1a are provided. The comparator 31 has a reference voltage set such that when the terminal voltage of the battery 4 drops to, for example, 14.0 V or less, the output voltage switches to a high level and the charge request signal C1 is output. That is, the charge request signal C1 is output when the terminal voltage of the battery 4 becomes equal to or lower than the reference voltage, and substantially detects a change in the terminal voltage of the battery 4. In FIG. 1, 7
Is an ignition key, and 8 is an electric load such as an air conditioner or a headlight. When these electric loads are used, the switch 9 is closed. In addition, concrete IC
The circuit configuration of the regulator 3 is, as shown in FIG. 2, one monolithic IC 3a and three resistors 3b, 3
c, 3d and 6 transistors 3e, 3f, 3g, 3
The one formed by h, 3j, 3k, the capacitor 3m, and the diode 3n can be cited. Monolithic IC3a
May have a circuit configuration known in the art, and turns on the transistors 3e and 3f to turn on the charge lamp connected to the L terminal 3p, and turns on the transistors 3h and 3j to turn on the F terminal. It has a function of energizing the rotor coil 1a connected to 3q. The inverted generation request signal C2 is applied to the base of the transistor 3j via the resistor 3b, and the inverted charging request signal C1 is output to the electronic control unit 5 via the resistor 3c. . The IG terminal 3r is connected to the ignition key 7, the B terminal 3s is connected to the positive terminal of the battery 4, and the P terminal 3t is connected to one end of the field coil. The E terminal 3u is a ground terminal.

The electronic control unit 5 controls the operation of the engine 2 and is provided with a central processing unit, a storage unit, an input interface and an output interface and responds to changes in the engine speed, intake pressure and electric load. Then, the fuel injection amount is calculated to control the operation in a state substantially equal to the stoichiometric air-fuel ratio. Further, in order to control the charging of the battery 4, the charging request signal C1 is input to the input interface.
Each time the charge request signal C1 is input, its duration is measured and stored in the storage device. Then, when the electric load 8 is turned on, the electronic control unit 5 gradually decreases the power generation prohibited state, in other words, gradually increases the power generation permitted state (gradual excitation control).
Is programmed to the control of the alternator 1 so as to change the ON (power generation permission) / OFF (power generation prohibition) ratio (duty ratio) of the power generation prohibition signal C2 and output it to the AND circuit 32. There is. An outline of the control program of the alternator 1 is shown in the flow chart of FIG.

Next, the operation of the present invention will be described with reference to FIG.

First, when the ignition key 7 is closed, the terminal voltage of the battery 4 is applied to the comparator 31 of the IC regulator 3. As shown in FIG. 4, the comparator 31 does not output the charging request signal C1 while the input terminal voltage exceeds the reference voltage. When the charge request signal C1 is not output, the switching transistor 33 does not turn on because the logical product cannot be obtained even if the power generation inhibition signal C2 input to the AND circuit 32 is turned on, and therefore the rotor coil 1a does not turn on. No current flows and the alternator 1 does not charge the battery 4. Generally, in a state where a large electric load 8 such as an air conditioner or a headlight is not applied, the terminal voltage of the battery 4 may drop below the reference voltage for a short period of time substantially. The signal C1 is output (the period until the electric load is applied in FIG. 4), and the switching transistor 33
Is turned on and the rotor coil 1a is energized. As a result, the alternator 1 generates power and the battery 4 is charged.

Next, for example, when the air conditioner is operated,
The switch 9 is closed, and the electric load 8 is electrically connected to the battery 4. When the electric load 8 is turned on, the terminal voltage of the battery 4 becomes lower than the reference voltage.
Therefore, the comparator 3a outputs the charge request signal C1, and the electronic control unit 5 determines that the electric load is applied when the charge request signal C1 lasts longer than the previously input charge request signal C1. Yes (Step S
(YES judgment in 1). Then, after determining the electric load, it is determined whether or not the idle operation is being performed (step S2),
When not in the idle operation, the electronic control unit 5 controls the duty ratio of the power generation prohibition signal C2 so that the ON ratio gradually increases after a predetermined time delay and outputs the power generation prohibition signal C2 to the AND circuit 32 ( Step S5). As a result, AND is performed only while the power generation prohibition signal C2 is on.
The circuit 32 outputs a high level voltage and turns on the switching transistor 33. Therefore, a current for power generation intermittently flows in the rotor coil 1a in accordance with the duty ratio, power generation and non-power generation are repeated, and the output current of the alternator 1 gradually increases to slow down the engine rotation. Charge without charging. Then, the power generation prohibition signal C2 in which charging is performed by the gradual excitation control in this manner
When the charge request signal C1 is turned off when the power is turned on, it is determined that the charging is no longer necessary and the gradual excitation control is stopped (YES determination in step S6).

On the other hand, when the electric load 8 is turned on during the idle operation, the control is executed as follows. That is, since it is determined that the electric load 8 has been turned on along with the control of charging, the electronic control unit 5 increases the intake air amount to increase the idle speed during the idle operation. Control to raise. That is, when the electric load 8 is turned on, the alternator 1 starts power generation, and the engine 2 is loaded. For this reason, assuming that the intake air amount is the same as before, the idle speed will decrease (shown by the one-dot chain line in FIG. 4), and an air amount sufficient to compensate for the decrease is assumed. The ISC actuator 6 is controlled so as to inhale, and the engine speed is controlled so as not to fall below a predetermined idle speed. In this case, it is determined whether the electric load 8 is turned on (step S1)
After that, it is determined that the idle operation is in progress (step S
(YES determination in 2). After that, the opening of the ISC actuator 6, specifically, the opening duty ratio is changed and gradually increased (step S3). This gradual increase of the opening duty ratio is executed from the time when the electric load 8 is detected before the power generation inhibition signal C2 is changed. Then, it is determined that the predetermined time has elapsed (YE in step S4
(Determination of S), and then step S5 and step S6 are executed. As described above, in the control of the ISC actuator 6, the correction corresponding to the electric load 8 is performed by changing the opening duty ratio which is the opening signal of the ISC actuator 6 prior to the change of the duty ratio of the power generation inhibition signal C2. It is possible to effectively compensate for the delay of the air and delay the rise of the torque to effectively prevent a rapid rise and fall of the engine rotation.

In this way, the charging of the battery 4 is controlled, and the intake air amount during idle operation is adjusted to control the idle speed. Further, when the electric load 8 applied to the engine 2 in the idling state overlaps, the load applied to the engine 2 by the alternator 1 is gradually increased. In other words, if the power generation amount of the alternator 1 is gradually increased, the engine rotation will drop. Can be effectively suppressed. As a result, it is possible to reduce fluctuations in the idle speed. Further, even if the power generation prohibition signal C2 is output even when the charging request signal C1 is output, it is possible to prevent overcharge during downhill (power generation prohibition signal off) by turning on / off according to the operating state of the engine 2. , It is possible to ensure smooth acceleration by prohibiting charging during acceleration.

Next, an embodiment of the invention according to claim 2 of the present application will be described with reference to FIGS. Note that the configuration of the engine 2 including the ISC actuator 2 is the same as that of the above-mentioned embodiment, and therefore its explanation is omitted. In this embodiment, as shown in FIG. 5, the electronic control unit 105 is connected to the comparator 131 of the IC regulator 103.
The power generation state of the alternator 101 is determined by the power generation signal GS, and the adjusted voltage switching signal CS having the first voltage value V1 and the second voltage value V2 lower than the first voltage value V1 is output based on the power generation signal GS. Therefore, the comparator 131 is configured to output the power generation request signal DS requesting power generation to the switching transistor 133 when the terminal voltage of the battery 4 lower than the first voltage value V1 is input.

More specifically, the IC regulator 103 is
A comparator 131 having a − terminal connected to the positive terminal of the battery 4 and a + terminal connected to the electronic control unit 105.
And a switching transistor 133 that turns on and off according to the power generation request signal DS output from the comparator 131 to control the current flowing through the rotor coil 101a, and a diode 134 that absorbs the surge voltage of the rotor coil 101a.
And a resistor 135 for detecting the power generation state from the energized state of the rotor coil 101a. Comparator 13
The adjustment voltage switching signal CS is applied to the + terminal of No. 1, and in this embodiment, the first voltage value V1 is, for example, 1
4.0V is set as the second voltage value V2, for example, 12.5V. One end of the resistor 135 is connected to the electronic control unit 105, and the power generation signal GS is input to the electronic control unit 105. It should be noted that as a specific circuit configuration of the IC regulator 103, as shown in FIG.
Resistors 103x, 103y and four transistors 10
3e, 103f, 103g, 103h and capacitor 10
The one formed of 3 m and the diode 103 n may be mentioned. The monolithic IC 103a may have a circuit configuration known in the art, and the adjustment voltage switching signal CS input via the resistor 103x and the IG terminal 10 may be used.
While comparing the terminal voltage of the battery 4 input via 3r, the transistors 103e and 103f are turned on to turn on the charge lamp connected to the L terminal 103p, and the transistors 103g and 103h are turned on to turn on the F
It has a function of energizing the rotor coil 1a connected to the terminal 103q. The power generation signal GS is output to the electronic control unit 105 via the resistor 103y. IG terminal 10
3r is connected to the ignition key 9 and the B terminal 103
s is directly connected to the positive terminal of the battery 4, and the P terminal 10
3t is connected to one end of the field coil. The E terminal 103u is a ground terminal.

The electronic control unit 105 controls the operation of the engine 2 similarly to the above-mentioned embodiment, and is provided with a central processing unit, a storage unit, an input interface and an output interface, and the engine 2 rotational speed, intake pressure and It is programmed to calculate the fuel injection amount and control the operation in a state substantially equal to the stoichiometric air-fuel ratio according to the change of the electric load. In addition, in order to control the charging of the battery 4,
The power generation signal GS is input to the input interface, and when the electric load 8 is applied, the electronic control unit 105 outputs the adjustment voltage switching signal CS to the first voltage value V1 and the second voltage value. While switching to V2 alternately, the second
It is programmed to gradually reduce the duration of the voltage value V2 and control the switching transistor 133 so that the amount of power generation gradually increases. That is, the adjustment voltage switching signal C
S switches between the first voltage value V1 and the second voltage value V2 and outputs it to the switching transistor 133, but the duration of the first voltage value V1 is gradually changed to a long time (gradual excitation control), resulting in power generation. The quantity is programmed to increase corresponding to the duration of the first voltage value V1. An outline of the control program of the alternator 1 is shown in a flowchart in FIG.

Next, the operation of the present invention will be described with reference to FIG.

As shown in FIG. 8, the adjustment voltage switching signal CS
Is maintained at the first voltage value V1 until it is detected that the electric load 8 is turned on. Therefore, every time the terminal voltage of the battery 4 falls below the first voltage value V1, the comparator 131
Represents the power generation request signal DS to the switching transistor 133
Output to. The switching transistor 133 is turned on each time the power generation request signal DS is applied, and the rotor coil 10
A current flows through 1a, and the alternator 101 generates power. Here, the electronic control unit 105 detects the duration of the power generation request signal DS, that is, the power generation request time, from the duration of the power generation signal GS, and stores the value. This power generation required time is used to determine whether or not the electric load 8 has been turned on.

On the other hand, when the electric load 8 is turned on, the terminal voltage of the battery 4 decreases for a longer period of time than when the electric load 8 is not applied. As a result, the current power generation request time becomes longer than the stored previous power generation request time, and the electronic control unit 105 determines that the electric load 8 has been turned on (YES determination in step S11). That is,
The power generation signal GS (the inverted waveform thereof is shown in FIG. 8) input to the electronic control unit 105 is provided unless the adjustment voltage switching signal CS is switched to the second voltage value V2 by the electric load 8 being turned on. While the electric load 8 is turned on, it is at a low level (logically true), and lasts longer than before the electric load 8 is turned on. If you decide to apply an electrical load,
It is determined whether or not the idle operation is being performed (step S12). If the idle operation is not being performed, the electronic control unit 105
The adjustment voltage switching signal CS is output to the C regulator 103 for a duration of the first voltage value V1 longer than that of the second voltage value V2. The ratio of the durations of the first voltage value V1 and the second voltage value V2 is such that the duration of the second voltage value V2 gradually increases and the duration of the first voltage value V1 decreases correspondingly. Is changed with the progress of (step S1
5). As a result, immediately after the electric load 8 is turned on, the power generation request signal DS is output from the comparator 131 to the switching transistor 133 only for a short time, and the amount of power generation of the alternator 101 is small because the energization of the rotor coil 101a is short. After that, since the ratio of the respective voltage values of the adjustment voltage switching signal CS changes, the rotor coil 10
The energization time of 1a gradually increases, and the power generation amount of the alternator 101 increases. Then, when the output current of the alternator 101 reaches a predetermined value (YES determination in step S16), the ratio of the durations of the first voltage value V1 and the second voltage value V2 is fixed to a steady state.

As described above, also in this embodiment, since the energization time to the rotor coil 101a is gradually lengthened,
The power generation amount of the alternator 101 will gradually increase. Therefore, for the engine 2, the alternator 101 is shifted from the light load state to the full load state, so that the influence on the engine rotation can be reduced, and as a result, the drop of the engine rotation can be effectively prevented. . Also,
If the ISC actuator 6 is controlled when the electric load 8 is turned on prior to the control of the power generation amount as described above, a drop in the idling speed during idling (as indicated by the dotted line in FIG. 8), as in the above embodiment. Can be controlled accurately. That is, in step S11, the introduction of the electric load 8 is detected, and it is determined whether or not the idle operation is being performed (step S12). If the idle operation is being performed, the opening degree of the ISC actuator 6 is gradually increased in step S13. The control of the ISC actuator 6 is performed from the time when it is determined that the electric load 8 is applied. Then, after a predetermined time has elapsed (YES determination in step S14), steps S15 and S16 are executed.
The respective inventions according to claim 1 and claim 2 of the present application are not limited to the respective embodiments described above.

Besides, the configuration of each part is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0031]

According to the inventions of claims 1 and 2 of the present application,
As detailed above, when an electrical load is applied,
Since the amount of power generated by the alternator is gradually increased based on the signal output from the external control means, it is possible to prevent the alternator from maximally generating power at the same time when the electric load is turned on so that the engine load is momentarily increased. Therefore, it is possible to prevent the engine speed from decreasing and the drivability from deteriorating. Moreover, since the IC regulator is controlled by the external control means,
It is not necessary to change the electric circuit and structure inside the alternator, and it is possible to prevent the alternator from being complicated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electric circuit configuration of an embodiment of the invention according to claim 1 of the present application.

FIG. 2 is an electric circuit diagram of a specific example of the IC regulator of the embodiment.

FIG. 3 is a flowchart schematically showing a control procedure of the embodiment.

FIG. 4 is a waveform diagram illustrating the operation of the same embodiment.

FIG. 5 is a block diagram showing an electric circuit configuration of an embodiment of the invention according to claim 2 of the present application.

FIG. 6 is an electric circuit diagram of a specific example of the IC regulator of the embodiment.

FIG. 7 is a flowchart schematically showing the control procedure of the embodiment.

FIG. 8 is a waveform diagram illustrating the operation of the same embodiment.

[Explanation of symbols]

 1, 101 ... Alternator 2 ... Engine 3, 103 ... IC regulator 4 ... Battery 5, 105 ... Electronic control device 6 ... ISC regulator 8 ... Electric load

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Mizuno 1-1, Showa-cho, Kariya city, Aichi Prefecture

Claims (3)

[Claims] 1. An electric power generation amount of an alternator having a built-in IC regulator for adjusting the amount of electric power supplied to a rotor coil according to a voltage change of a driving power source mechanically driven by an engine and selectively connected to an electric load. A control method of an alternator controlled by an external control means, wherein the control means detects the turning-on of the electric load based on a duration of a charge request signal output from the IC regulator based on the voltage of the driving power supply. Before the electric load is turned on, the electric power generation prohibition signal output from the control means to the IC regulator is invalidated to control the amount of electric power generation according to the charge request signal, and after the electric load is turned on, a prohibited state is set. The power generation amount is gradually increased during the period in which the charge request signal is output by enabling the power generation prohibition signal while gradually shortening Control method of the alternator to be. 2. The amount of power generated by an alternator having an IC regulator for adjusting the amount of electricity supplied to a rotor coil in accordance with a change in voltage of a driving power source that is mechanically driven by an engine and is selectively connected to an electric load. A method for controlling an alternator controlled by external control means, comprising supplying an adjustment voltage switching signal having a first voltage value and a second voltage value lower than the first voltage value to the IC regulator, The control means detects that the electric load is turned on from the duration of the generated voltage, and power is generated when the voltage of the driving power supply is lower than the first voltage value of the adjustment voltage switching signal before the electric load is turned on. As described above, the alternator is controlled so that after the electric load is turned on, the second voltage is switched while the adjustment voltage switching signal is alternately switched between the first voltage value and the second voltage value. A control method for an alternator, characterized in that the duration of a pressure value is gradually shortened and the amount of power generation is gradually increased. 3. An engine is provided with an ISC actuator for controlling an intake air amount during idle operation, and the opening of the ISC actuator is gradually increased by the control means when the input of an electric load is detected, and the opening of the ISC actuator is increased. The method of controlling an alternator according to claim 1 or 2, wherein the power generation amount is gradually increased with a delay after the first increase is started.